JP5109099B2 - Personal vehicle - Google Patents

Description

  The present invention can be used in personal vehicles such as electric wheelchairs.

  An electric wheelchair will be described as an example of a typical personal vehicle. An electric wheelchair equipped with an electric unit basically follows the structure of a manual wheelchair, and the front caster drive wheel (front wheel) is small so as not to obstruct getting on and off. Therefore, the height of the step that can be traversed is low (usually about 2 to 3 cm). For example, inconvenience may occur even when traversing the low step when climbing from the roadway to the sidewalk.

For this reason, various proposals have been made so far to add the ability to overcome the steps to electric wheelchairs. The proposals can be broadly classified as follows: (1) a technique for modifying the shape of the front caster drive wheel (size, groove, etc.), and (2) a method for adding a special mechanism or actuator for lifting the vehicle body (Patent Document 1, Patent Document) 2, Patent Document 3), (3) Method of lifting the front caster drive wheel by human weight shift etc. (Patent Document 4, Patent Document 5, Patent Document 6), (4) Center of gravity position by the front and rear slide mechanism of the seat surface There is a method of lifting the front caster drive wheel by changing (Patent Document 7).
Utility model registration No. 3077814 JP 2001-212181 A Japanese Unexamined Patent Publication No. 2006-280616 Japanese Patent Laid-Open No. 2001-314450 JP 2004-202264 A Utility model registration No. 3028282 Japanese Patent Laid-Open No. 2001-37816

  According to the above-described technique, it is not always sufficient to achieve a running stability and a good traversability with respect to a step with a simple mechanism. For this reason, there is a need in the industry for a personal vehicle that has a simple mechanism that provides running stability on the road surface and good traversability against steps.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a personal vehicle having a running stability on a road surface and a good leveling performance with respect to a step with a simple mechanism.

A personal vehicle according to a first aspect of the invention (hereinafter also referred to as a vehicle) includes a vehicle body having a seating portion on which a user is seated, drive wheels attached to the vehicle body on the left and right sides thereof, and drive wheels attached to the vehicle body. A driving source for rotational driving; an operating unit for controlling driving of the driving source; a front wheel attached to the vehicle body positioned in front of the driving wheel; a rear wheel support member attached to the vehicle body; and a road surface The rear wheel is attached to the rear wheel support member in such a manner that it can be grounded, and when contacting the road surface, a rear wheel positioned on the rear side of the ground point of the driving wheel, and the rear wheel support member is operated to cause the rear wheel to move to the road surface An actuator for grounding and floating with respect to
The front wheels are provided on the left and right sides of the vehicle body, the rear wheels are singular, the first mode is a mode in which the left and right drive wheels, the left and right front wheels and the rear wheels are driven, and the left and right front wheels. A control device capable of switching between a second mode, which is a mode for driving the left and right drive wheels and the rear wheels while floating, and a travel speed detecting means for detecting a travel speed of the personal vehicle, and / or A target travel speed setting means for setting a speed target value of the travel speed in the moving direction of the personal vehicle is provided, the operation unit is switched to the second mode, and the travel speed in the forward direction is equal to or higher than the set speed. When at least one of the conditions that the speed target value in the forward direction by the operation unit is equal to or greater than a certain value is satisfied, the control device And performing control for switching from mode to the second mode.

  A personal vehicle according to a second aspect of the present invention includes a vehicle body having a seating portion on which a user is seated, drive wheels attached to the left and right sides of the vehicle body, and a drive source attached to the vehicle body for rotationally driving the drive wheels. An operation unit that controls driving of the drive source; a front wheel that is positioned in front of the drive wheel and attached to the vehicle body; a rear wheel support member that is attached to the vehicle body; A rear wheel mounted on a wheel support member and positioned on the rear side of the ground point of the drive wheel when contacting the road surface, and the rear wheel support member is operated to ground and float the rear wheel with respect to the road surface A first mode for traveling with at least the driving wheel and the front wheel, and a second traveling with the driving wheel and the rear wheel in contact with the road surface with the front wheel floating. Comprising a control device capable of switching and over de, a,
  Travel speed detecting means for detecting the travel speed of the personal vehicle and / or target travel speed setting means for setting a speed target value of the travel speed in the moving direction of the personal vehicle are provided, When at least one of the following conditions is satisfied: switching to the second mode, that the traveling speed in the forward direction is greater than or equal to the set speed, and that the speed target value in the forward direction by the operation unit is greater than or equal to a certain value. The control device performs control to switch from the first mode to the second mode.

  When the actuator operates in one direction, the rear wheel moves in a direction that increases the degree of contact of the rear wheel with the road surface. As a result, the vehicle can travel in a mode in which the vehicle travels on the drive wheels, front wheels, and rear wheels. On the other hand, when the actuator operates in the other direction, the rear wheel moves in the direction of rising from the road surface. As described above, the actuator can be switched between grounding of the rear wheel provided behind the driving wheel (increasing the degree of grounding on the road surface) and flying. If the rear wheels are in contact with the road surface, the vehicle can stably travel with the drive wheels and the rear wheels even if the front wheels are lifted off the road surface. Therefore, if the front wheels are lifted off the road surface with the drive wheels and the rear wheels in contact with the ground, the vehicle can travel in the front wheel lifting mode. In this case, since the rear wheels are in contact with the road surface in addition to the driving wheels, the posture of the vehicle body can be stably maintained.

  Further, when the vehicle gets over the step, if the rear wheel support member is operated and the rear wheel is moved in a direction in which the degree of contact of the rear wheel attached to the rear wheel support member (the degree of contact with the road surface) increases, When the driving wheel rides on the step, the assist force by the rear wheel can be exhibited. Thus, even when the level difference is high, the vehicle can easily get over the level difference.

The personal vehicle described for reference includes a vehicle body having a seating portion on which a user is seated, drive wheels attached to the vehicle body on the left and right sides, a drive source that is attached to the vehicle body and rotationally drives the drive wheels, and drive of the drive source A front wheel mounted on the vehicle body in front of the driving wheel, a rear wheel support member mounted on the vehicle body, and a rear wheel support member that can be grounded on the road surface and grounded on the road surface A rear wheel positioned behind the ground point of the drive wheel, an actuator for operating the rear wheel support member to ground and float the rear wheel with respect to the road surface, and a first traveling at least on the drive wheel and the front wheel And a control device capable of switching between a mode and a second mode of traveling while grounding the driving wheel and the rear wheel with the front wheel floating.

  When the actuator is operated in one direction by the control device, the rear wheel moves in a direction that increases the degree of contact with the road surface. As a result, the vehicle can run in a mode in which the vehicle runs on the drive wheels, front wheels, and rear wheels. On the other hand, when the actuator is operated in the other direction by the control device, the rear wheel can move in the direction of rising from the road surface. As described above, the actuator can be switched between grounding of the rear wheel provided behind the driving wheel (increasing the degree of grounding on the road surface) and flying.

  Here, if the rear wheel is in contact with the road surface in addition to the drive wheel, the vehicle can stably travel with the drive wheel and the rear wheel even if the front wheel is lifted off the road surface. Therefore, if the front wheels are lifted off the road surface with the drive wheels and the rear wheels in contact with the ground, the vehicle can travel in the front wheel lifting mode. Since the rear wheels are grounded in addition to the driving wheels, the vehicle body posture in the second mode (front wheel floating mode) can be stably maintained.

  In addition, when the vehicle gets over the step, the control device operates the rear wheel support member, and if the rear wheel is moved in the direction in which the degree of ground contact of the rear wheel attached to the rear wheel support member increases, When riding on a step, it is possible to exert the assist force by the rear wheels. Thus, even when the level difference is high, the vehicle can easily get over the level difference.

  ADVANTAGE OF THE INVENTION According to this invention, the personal vehicle provided with the running stability in a road surface with the simple mechanism and the favorable traversing property with respect to a level | step difference can be provided.

  According to the present invention, stepping over a step is easily realized by adding a rear wheel support member and an actuator for operating the rear wheel support member to a vehicle body constituting a personal vehicle represented by an electric wheelchair or the like. be able to. As described above, according to the present invention, it is possible to reduce the device added to the driving mechanism of a personal vehicle such as an electric wheelchair, and thus it is possible to suppress the conventional driving feeling from being greatly impaired.

  The personal vehicle includes a vehicle body having a seating portion on which a user is seated, drive wheels attached to the left and right sides of the vehicle body, a drive source that rotationally drives the drive wheels, an operation unit that controls drive of the drive source, and drive wheels A front wheel attached to the vehicle body in front of the rear wheel, a rear wheel support member attached to the vehicle body so that the front end of the drive wheel extends beyond the ground point, and a rear wheel support member attached to the rear wheel support member A wheel and an actuator that grounds and floats the rear wheel by moving the rear wheel support member up and down relative to the road surface are provided. The drive source is exemplified by a motor. The drive wheels are attached to the left and right sides of the vehicle body. In general, the diameter of the drive wheels is preferably larger than the diameters of the front wheels and the rear wheels, but in some cases, the front wheels and the rear wheels may have the same diameter. good. The drive source is for rotating the drive wheel, and a motor is exemplified. The operation unit is controlled by an operator (generally, a person sitting on the seating unit or a caregiver) to drive the drive source. The operation unit may be attached to the vehicle body, may be separated from the vehicle body, or may be wireless. The front wheel is located in front of the drive wheel and is attached to the vehicle body. The rear wheel support member attaches the rear wheel to the vehicle body. Examples of the rear wheel support member include a bar shape and a plate shape, but the shape is not particularly limited. The rear wheel is attached to the rear wheel support member. When the rear wheel is in contact with the road surface, the ground point of the rear wheel is located behind the ground point of the driving wheel. The actuator raises and lowers the rear wheel support member with respect to the road surface to ground and float the rear wheel, and examples thereof include a motor, a pneumatic cylinder device, a hydraulic cylinder device, and an electromagnetic device. The actuator may be a direct acting type or a rotating type.

  According to one aspect of the present invention, the front wheels are provided on the left and right sides of the vehicle body, the rear wheels are singular, and the first mode is a five-wheel mode in which the vehicle runs on the left and right drive wheels, the left and right front wheels, and the rear wheels ( The second mode (front wheel levitation mode) is a three-wheel mode in which the left and right driving wheels and the rear wheels are driven while the left and right front wheels are levitated. However, a single front wheel may be provided at the center in the vehicle width direction, and a plurality of rear wheels may be provided on both sides in the vehicle width direction.

  The first mode represented by the five-wheel mode or the like can mainly be intended for stable running, improved turning performance, stable starting on a slope, and stable running on a slope. If the driving wheels, front wheels, and rear wheels are on the left and right sides of the vehicle body, the first mode is the six-wheel mode. In short, the first mode is a mode in which the front wheels are in contact with the road surface, and there are more wheels that are in contact with the road surface than in the second mode (the front wheel floating mode in which the front wheels are floating on the road surface). The above-mentioned second mode, that is, the front wheel floating mode (for example, the three-wheel mode) is mainly used for steps that cannot be run in the first mode, stepping over grooves, reducing vibrations generated in the first mode, and reclining effect of the riding posture. It can be intended to improve comfort. The personal vehicle is preferably provided with a rear wheel state detecting means for detecting the ground contact and the rising of the rear wheel with respect to the road surface. Examples of the rear wheel state detection means include a micro switch, a limit switch, a pressure sensor, an optical sensor, and an electrostatic sensor.

It is preferable that a travel speed detection stage for detecting the travel speed of the vehicle and / or a target travel speed setting means for setting a speed target value for the travel speed in the direction of movement (including forward and reverse) of the vehicle is provided. . Examples of the traveling speed detection means include a sensor that detects rotation of the drive wheel and a sensor that detects rotation of a motor that rotates the drive wheel. The sensor is exemplified by an encoder. The target travel speed setting means is used by a user or an assistant to set a speed target value of the travel speed in the moving direction of the vehicle, and examples thereof include a joystick and a button switch. When the inclination angle degree for pitch axis of the vehicle, including the weight of the user and .theta.1, it is preferable that the sensor for detecting the inclination angle .theta.1 is provided. This sensor is exemplified by an accelerometer and a rate gyro, but is not limited thereto. In addition, it is preferable that a sensor for detecting the road surface inclination angle α is provided when the road surface inclination angle on which the vehicle travels is α. This sensor is exemplified by an accelerometer and a rate gyro, but is not limited thereto.

  According to the personal vehicle of the present invention, it is preferable that the following control mode exemplified is executed.

  * The operation part has been switched to the second mode (front wheel floating mode), the traveling speed in the forward direction is not less than the set speed, and the speed target value by the operation part in the moving direction is not less than a certain value. When at least one of the conditions is satisfied, the control device operates the rear wheel support member to relatively move the rear wheel in the direction of rising from the road surface (even when the rear wheel remains in contact with the road surface). It is preferable to perform control to switch from the first mode to the second mode (front wheel floating mode). If the traveling speed is equal to or higher than the set speed, it is easy to switch to the second mode by raising the front wheels by the driving torque.

  * When switching from the first mode to the second mode (front wheel levitation mode), the control device operates the rear wheel support member to position the rear wheel to lift from the road surface, and also controls the personal vehicle including the weight of the user. It is preferable to perform control to apply driving torque to the driving wheels such that the position of the center of gravity is located behind the ground point of the driving wheels. Accordingly, the front wheel can be lifted from the first mode and easily switched to the second mode. Since the rear wheels are in contact with the ground, excessive leaning toward the rear of the vehicle body can be suppressed.

  * When switching from the first mode to the second mode, the control device increases the total drive torque T applied to the left and right drive wheels as the pitch direction inclination angle θ1 of the center of gravity of the personal vehicle including the weight of the user increases. It is preferable to perform control. As a result, the front wheels can be moved in the direction of raising and can be easily switched from the first mode to the second mode. In this case, if the driving torque T according to the pitch direction inclination angle θ1 is continuously applied to the driving wheels, the second mode (front wheel floating mode) traveling can be maintained.

  * When switching from the first mode to the second mode, it is preferable that the control device performs control to increase the total driving torque T applied to the left and right driving wheels when the road surface inclination angle α increases. Thereby, it is possible to easily switch from the first mode to the second mode.

  * When switching from the first mode to the second mode, it is preferable that the control device performs control to increase the total driving torque T applied to the left and right driving wheels when the road surface inclination angle α increases. Thereby, it is possible to easily switch from the first mode to the second mode. In this case, traveling in the second mode (front wheel floating mode) can be maintained by applying driving torque T corresponding to the road surface inclination angle α to the driving wheels.

  * In addition, when switching from the first mode to the second mode, when the pitch direction inclination angle θ1 and / or the road surface inclination angle α of the gravity center position of the personal vehicle including the weight of the user increases, the control device It is preferable to perform control to increase the total driving torque T applied to the motor. Thereby, it is possible to easily switch from the first mode to the second mode. In this case, if the driving torque T corresponding to the pitch direction inclination angle θ1 and / or the road surface inclination angle α is applied to the driving wheels, the second mode (front wheel floating mode) traveling can be maintained.

  * When the operation unit is suddenly operated, the personal vehicle may suddenly stop or retreat suddenly. In this case, the posture of the personal vehicle may be impaired. According to a preferred embodiment in this regard, the control device includes a filter unit that cuts a high-frequency component higher than a predetermined cutoff frequency in an input signal (for example, a speed command value from the operation unit) by the operation unit. . As a result, a high frequency component (corresponding to when the operating unit is suddenly operated) higher than a predetermined cutoff frequency in the input signal (for example, a speed command value from the operating unit) by the operating unit is cut. Therefore, even if the operation unit is operated suddenly, the possibility that the personal vehicle suddenly stops or retreats is reduced or avoided. In this case, the first mode or the second mode (front wheel floating mode) may be used. The cut-off frequency may be set independently in accordance with the input signal from the operation unit at the time of forward command and the time of reverse command.

  * The cut-off frequency f is preferably determined according to the road surface inclination angle α and / or the inclination angle θ1 in the pitch direction. Here, the cut-off frequency f can be set according to the road surface inclination angle α. For example, the cut-off frequency f is preferably divided into a form in which the cut-off frequency f is increased when the road surface inclination angle α is increased and a form in which the cut-off frequency f is decreased when the road surface inclination angle α is increased. The former form is, for example, a case where excessive tilting forward is suppressed in a three-wheel state. The latter form is, for example, a case where rearward overturning is suppressed in a three-wheel state or a five-wheel state.

  * When the vehicle is traveling in the second mode (front wheel floating mode), the stability of the posture of the personal vehicle may be impaired when the rear wheel attached to the rear wheel support member floats from the road surface. According to a preferred embodiment in this regard, the control device decelerates the rotational speed of the drive wheel when the rear wheel of the rear wheel support member floats from the road surface when traveling in the second mode (front wheel floating mode). Alternatively, it is preferable to perform control to perform at least one of an operation of stopping and an operation of lowering the rear wheel support member and lowering the rear wheel toward the road surface.

  * When there is a convex step in the moving direction (forward direction) of the drive wheel, the drive wheel may not be able to get over the step. According to a preferred embodiment in this regard, the control device directs the rear wheel support member toward the road surface in a direction in which the rear wheel pushes the road surface while rotating the drive wheel when there is a convex step in the forward direction of the drive wheel. It is preferable to perform control that assists the rear wheels to overcome the step difference of the drive wheels by lowering the rear wheels. In this case, even when the level difference is high, the driving wheel can get over the level difference with the assistance of the rear wheel.

  * It is preferable that a detecting means for detecting slip of the driving wheel is provided. The detection means may be a slip sensor or may be detected by software.

  * When the front wheels travel on a convex step, slipping of the drive wheels may be detected. In this case, since the drive wheels are slipping, the personal vehicle may not be able to travel. According to a preferred embodiment in this regard, the control device operates the rear wheel support member in the direction in which the rear wheel is raised when slippage of the driving wheel is detected when the front wheel travels a convex step. As a result, it is possible to perform control for releasing the slip of the drive wheel by moving the rear wheel in the direction of separating from the road surface and improving the grounding property of the drive wheel.

  * When at least one of the following conditions is satisfied: the forward speed is equal to or higher than the set speed, and the speed target value by the forward direction operation unit is equal to or higher than a certain value, the control device supports the rear wheel. It is possible to control to switch from the first mode to the second mode (front wheel floating mode) by operating the member and moving the rear wheel in the direction of lifting from the road surface. In this case, it is preferable to apply drive torque to the drive wheels in accordance with the road surface inclination angle α and / or the inclination angle θ1 in the pitch direction.

  * When the control device detects that the driving wheel has shifted to the upper surface of the convex step, the control device causes the rear wheel to descend by operating the rear wheel support member and lowering the rear wheel. It is preferable to set the mode. Since the rear wheels are in contact with the ground as described above, the personal vehicle can stably travel on the upper surface of the step in the first mode. Note that the fact that the drive wheel has shifted to the upper surface of the step can be estimated as the vehicle body is horizontal, and therefore can be detected based on the pitch direction inclination angle θ1 of the center of gravity of the vehicle body with the user placed. is there.

  * When the control device runs on the upper surface of the step in the first mode, descends the upper surface and transitions to the road surface, if the driving wheel slips, the rear wheel is lifted by the rear wheel support member to improve the grounding property of the driving wheel. It is preferable to carry out. In this case, if the drive wheel slips, the vehicle cannot move forward with the drive wheel torque. Therefore, if the drive wheel slips, the rear wheel support member lifts (lifts) the rear wheel, so that the drive wheel can effectively contact the lower surface of the step or the road surface. it can.

  The first embodiment of the present invention will be described below.

(Embodiment 1)
The personal vehicle 1 of the present embodiment corresponds to an electric wheelchair. The front (arrow Fx direction) indicates the direction in which the face of the user who is normally seated on the vehicle 1 is facing, and indicates the direction in which the vehicle 1 travels. The rear (arrow Rx direction) indicates the direction in which the face of the user who is normally seated on the vehicle 1 is facing away, and indicates the direction in which the vehicle 1 moves backward.

  As shown in FIG. 1A, a vehicle 1 includes a vehicle body 11 having a seating portion 10 on which a user is seated, and left and right drive wheels 12 (12R, 12L) that are attached to the vehicle body 11 on the left and right. A drive wheel motor 13 (13R, 13L) as a drive source for driving the drive wheel 12 to rotate, an operation unit 14 for controlling the drive of the drive wheel motor 13 (13R, 13L), and a front of the drive wheel 12. Left and right rotatable front wheels 15 attached to the vehicle body 11, a rear wheel support bar 16 as a rear wheel support member attached to the vehicle body 11 so as to extend rearward of the drive wheels 12, and a rear wheel support bar 16 is provided with a rotatable rear wheel 17 attached to the tip of 16 and an actuator 18 for grounding and floating the rear wheel support bar 16 with respect to the road surface 90.

  The drive wheel 12 includes a right drive wheel 12R and a left drive wheel 12L. The drive wheel motor 13 includes a right drive wheel motor 13R that rotationally drives the right drive wheel 12R, and a left drive wheel motor 13L that rotationally drives the left drive wheel 12L. Here, when it is necessary to distinguish the right driving wheel 12R and the left driving wheel 12L, they are referred to as a driving wheel 12R and a driving wheel 12L. The right driving wheel 12R and the left driving wheel 12L may be collectively referred to as the driving wheel 12. The seating portion 10 includes a seat portion 10a that supports the user's waist and a backrest portion 10c that supports the user's back.

  The operation part 14 is provided in the vicinity of the seating part 10 so that a user seated on the seating part 10 can operate. The drive wheel 12 is disposed directly below or near the center of gravity position G in the front-rear direction of the vehicle 1. The front wheel 15 is a caster drive wheel having a diameter smaller than that of the drive wheel 12 and larger than that of the rear wheel 17. Although the front wheels 15 are provided on the left and right, depending on circumstances, a single wheel may be provided in the center in the vehicle width direction. The rear wheel 17 has a diameter smaller than the diameters of the drive wheel 12 and the front wheel 15 and is exemplified by a caster drive wheel or an omni wheel that can move in the left-right direction of the vehicle body 11, but is not limited thereto. In addition, although the rear wheel 17 is arrange | positioned in the center of the vehicle width direction, you may provide in the right and left of a vehicle width direction, and the number of the rear wheels 17 is not specifically limited.

  FIG. 1B shows a state in which the vehicle 1 is traveling in the five-wheel mode. FIG. 1 (d) shows a state in which the vehicle 1 is traveling in the three-wheel mode. FIG. 1 (b) → FIG. 1 (c) → FIG. 1 (d) shows a mode of switching from the five-wheel mode to the three-wheel mode. FIG. 1 (d) → FIG. 1 (c) → FIG. 1 (b) shows a mode of switching from the three-wheel mode to the five-wheel mode. The ground contact point 12 c of the drive wheel 12 indicates a portion where the drive wheel 12 is in contact with the road surface 90.

  As shown in FIG. 1B, the vehicle 1 normally travels in the five-wheel mode (also referred to as A mode), which is the first mode, to obtain traveling stability. The five-wheel mode is a mode for traveling for the purpose of bringing the driving wheel 12, the front wheel 15 and the rear wheel 17 into contact with the road surface 90. The five-wheel mode can mainly be intended for stable running, improved turning performance, stable starting on a slope, and stable running on a slope.

  As shown in FIG. 1D, the three-wheel mode (also referred to as the B mode) which is the second mode (front wheel levitation mode) is a state where the front wheel 15 is sufficiently lifted from the road surface 90 and the drive wheel 12 and the rear wheel. In this mode, the vehicle travels for the purpose of bringing 17 into contact with the road surface 90. The three-wheel mode can mainly be intended to improve riding comfort by reducing steps generated in the five-wheel mode, stepping over grooves, reducing vibrations generated in the five-wheel mode, and reclining effect of the riding posture. Further, according to the five-wheel mode, the center-of-gravity position G is located near the contact point 12c of the drive wheel 12 or ahead of the contact point 12c. According to the three-wheel mode, the center-of-gravity position G is located behind the contact point 12c of the drive wheel 12. Here, the center-of-gravity position G means the center-of-gravity position of the entire vehicle 1 (excluding the left and right drive wheels 12) including the weight of the user. In this way, two traveling modes can be realized by one vehicle 1.

  FIG. 2 shows a block diagram of the control system. As shown in FIG. 2, the control device 2 performs control to switch between the five-wheel mode and the three-wheel mode. As shown in FIG. 2, the control device 2 includes a digital IO 20, an AD converter 21 having an interface function, a counter 22, a single or plural CPUs 23, and a DA converter 24 having an interface function. The digital IO 20 and the AD converter 21 receive signals from the operation unit 14 and the sensor system. The counter 22 receives signals from the left drive wheel encoder 55L and the right drive wheel encoder 55R. The left driving wheel encoder 55L can function as an angular velocity sensor, a rotation speed sensor, and a speed sensor (traveling speed detecting means) for the vehicle 1 for the left driving wheel 12L. The right drive wheel encoder 55R can function as an angular velocity sensor, a rotation speed sensor, and a speed sensor (traveling speed detection means) for the vehicle 1 for the right drive wheel 12R.

  The drive wheel drive system includes a right drive wheel motor 13R (first drive source), a right drive wheel motor driver 131 for driving the right drive wheel motor 13R based on a command from the CPU 23, and a left drive wheel. A motor 13L (second drive source) and a left drive wheel motor driver 132 for driving the left drive wheel motor 13L based on a command from the CPU 23 are provided. The right drive wheel motor driver 131 controls the right drive wheel motor 13R and the right drive wheel 12R. The left drive wheel motor driver 132 controls the left drive wheel motor 13L, and the left drive wheel 12L.

  The operation unit 14 is preferably held near the seating unit 10 in the vehicle body 11 so that a seated person sitting on the seating unit 10 can easily operate, but may be a remote control system separated from the vehicle body 11. The operation unit 14 includes a mode switching button 141 (mode switching switch) for the user to switch between the five-wheel mode and the three-wheel mode, and a speed command operation unit 142 (for example, a joystick) for commanding the speed of the vehicle 1 by the user. , Target travel speed setting means). In addition, when the speed command operation unit 142 is tilted forward, a forward command is output, and when the speed command operation unit 142 is tilted backward, a reverse command is output, and a speed target is increased according to the tilt angle. However, it is not limited to this method.

  The sensor system includes a grounding switch 50 (rear wheel grounding and / or levitation detection means, rear wheel state detection means) for detecting that the rear wheel 17 attached to the rear wheel support bar 16 is grounded and floated on the road surface 90. ), A rate gyro 52 provided on the vehicle body 11, an accelerometer 53 provided on the vehicle body 11, and a right provided on the vehicle body 11 for detecting the rotational speed and / or rotational angle of the right drive wheel 12R. The drive wheel encoder 55R, the left drive wheel encoder 55L provided on the vehicle body 11 for detecting the rotation speed and / or rotation angle of the left drive wheel 12L, and the position and / or inclination of the rear wheel support bar 16 A position sensor 57 provided in the vehicle body 11 is provided for detecting the position of the rear wheel support bar 16 by detecting the angle. The ground switch 50 is provided on the rear wheel support bar 16 or the vehicle body 11. Signals from the sensors and the encoders are input to the control device 2 via the digital IO 20, AD converter 21, and counter 22, respectively.

  The accelerometer 53 can detect acceleration in the forward and backward direction of the vehicle body 11 of the vehicle 1. As the output value of the accelerometer 53, when the vehicle 1 is tilted in the pitch direction, the acceleration corresponding to the tilt angle θ1 in the pitch direction of the gravity center position G of the vehicle 1 can be detected due to the influence of the gravitational acceleration. Therefore, the accelerometer 53 can detect the inclination angle θ1 in the pitch direction of the gravity center position G described above. The rate gyro 52 can detect the angular velocity in the pitch direction of the gravity center position G.

  Such an accelerometer 53 and the rate gyro 52 can function as a sensor for obtaining the road surface inclination angle α with respect to the horizontal line and / or the inclination angle θ1 of the vehicle body 11 in the pitch direction. The pitch direction means an inclination angle with respect to the axial center 12e in the radial direction of the drive wheel 12 in the forward direction of the vehicle 1 (arrow Fx, Rx direction). The radial axis center 12e of the drive wheel 12 corresponds to the pitch axis that is the center of movement in the pitch direction.

  As shown in FIG. 2, the bar drive system for driving the rear wheel support bar 16 includes an actuator 18 provided in the vehicle body 11 for operating the rear wheel support bar 16 and an actuator 18 based on a command from the control device 2. And a rear wheel support bar driver 19 for driving the vehicle. A command from the control device 2 is input to the right drive wheel motor driver 131, the left drive wheel motor driver 132, and the rear wheel support bar driver 19 to control them.

  Hereinafter, each control item which the control apparatus 2 which concerns on this embodiment performs is demonstrated. * Indicates a control item to be executed.

* Control to switch from 5-wheel mode travel to 3-wheel mode travel (Control A)
In the five-wheel mode, the vehicle 1 travels with a total of five wheels including the drive wheels 12, the front wheels 15, and the rear wheels 17 being in contact with the road surface 90, and traveling stability is high. On the other hand, in the three-wheel mode, the vehicle 1 travels while the driving wheel 12 and the rear wheel 17 are in contact with the road surface 90 with the front wheel 15 floating from the road surface 90. In the three-wheel mode, since the front wheel 15 is lifted from the road surface 90, even if there is a step in front of the traveling vehicle 1, the vehicle 1 can easily get over the step.

When both of the following conditions (i) and (ii) are satisfied, the mode switch button 141 is continuously or intermittently set for a certain time by an operator (generally a seated user) or the like. When operated, the control device 2 automatically switches the mode from the five-wheel mode to the three-wheel mode. The condition that the mode switching button 141 is operated for a certain period of time is that the mode switching button 141 is erroneously pressed, the speed command operation unit 142 (for example, a joystick) is erroneously operated, etc. This is to prevent it from occurring. If the forward traveling speed of the vehicle 1 is high, the center of gravity G of the entire vehicle 1 (excluding the left and right driving wheels 12) including the weight of the user can easily move backward from the ground contact point 12c of the driving wheels 12. The front wheel 15 is likely to float from the road surface 90, and the five-wheel mode is easily changed to the three-wheel mode.
(I) The forward travel speed V is equal to or higher than the set speed. (Ii) The forward speed target value Vtarget by the speed command operation unit 142 (for example, joystick) is equal to or higher than a predetermined value. When the mode switching button 141 functioning as a mode switching switch is operated continuously or intermittently for a certain period of time, the control device 2 does not depend on the moving speed of the vehicle 1 and starts from the three-wheel mode. Immediately shift to the five-wheel mode with high running stability. In this case, it does not depend on the actual forward travel speed and the target value of the forward speed.

  By the way, when traveling in the five-wheel mode, in order to shift from the five-wheel mode to the three-wheel mode, the center of gravity G of the entire vehicle 1 (excluding the left and right drive wheels 12) including the weight of the user. It is preferable to apply a drive torque such that is located behind the ground point 12 c of the drive wheel 12. At the same time, a command to lift the rear wheel support bar 16 upward (in the direction of arrow U, the direction of rising) is output to the actuator 18 while the rear wheel 17 is grounded to the road surface 90 in order to ensure the rearward tilt of the vehicle body 12. . As a result, the entire vehicle 1 moves forward and tilts backward (generally, the rear wheel 17 is grounded to the road surface 90) and shifts to the three-wheel mode.

  Thus, when shifting from the five-wheel mode to the three-wheel mode, the drive torque T generated in the left and right drive wheels 12 is equal to or greater than the torque calculated by the following equation (1).

図３は、式（１）で用いられるパラメータを示す。図３および式（１）において、Ｇは、使用者の体重を含むビークル１（駆動輪を除く）の重心位置を示す。図３に示すように、Ｐ１は、駆動輪１２の軸中心１２ｅ（ピッチ運動の中心であるピッチ軸）を通る鉛直線を示す。θ１は、使用者の体重を含むビークル１の重心位置Ｇが駆動輪１２の軸中心１２ｅ（ピッチ軸に相当）に対してピッチ方向（前方）へ傾斜している傾斜角度（駆動輪１２の軸中心１２ｅを通る鉛直線Ｐ１に対するピッチ方向傾斜角度）を示す。

FIG. 3 shows the parameters used in equation (1). In FIG. 3 and formula (1), G indicates the position of the center of gravity of the vehicle 1 (excluding the drive wheels) including the weight of the user. As shown in FIG. 3, P <b> 1 indicates a vertical line passing through the axis center 12 e (pitch axis that is the center of pitch motion) of the drive wheel 12. θ1 is an inclination angle (an axis of the drive wheel 12) in which the gravity center position G of the vehicle 1 including the weight of the user is inclined in the pitch direction (forward) with respect to the axis center 12e of the drive wheel 12 (corresponding to the pitch axis). The pitch direction inclination angle with respect to the vertical line P1 passing through the center 12e is shown.

  In FIG. 3, P <b> 2 indicates an imaginary line that passes through the center of gravity position G of the vehicle 1 and the axial center 12 e of the drive wheel 12. M1 represents the mass of the vehicle 1 (excluding the drive wheels) including the weight of the user (human). J1 represents the moment of inertia around the gravity center position G of the vehicle 1 (excluding the drive wheels) including the weight of the user (human). M2 represents the total mass of the left and right drive wheels 12. J2 indicates the moment of inertia of the drive wheel 12 around the gravity center position G. L indicates the distance (the distance parallel to the imaginary line P2) between the center of gravity position G and the axis center 12e of the drive wheel 12. R indicates the radius of the drive wheel 12. T represents the total drive torque of the left and right drive wheels 12R, 12L. g represents gravitational acceleration. α indicates an actual road surface inclination angle with respect to the horizon. α includes the slope of the step 95 when the step 95 is traversed. When the road surface inclination angle α is a positive value, it means that the road surface 90 becomes an uphill.

  The pitch direction inclination angle θ1 is obtained from the output value of the accelerometer 53 provided in the vehicle body 11 and the output value of the rate gyro 52. Specifically, the pitch direction inclination angle θ1 is the same as θHL, and, similarly to the case of θHL, the control device 2 integrates the angular velocity θg (dot) that is the output value of the rate gyro 52 with time integration ( (Corresponding to .theta.HL obtained by the rate gyro 52) is obtained, and a value .theta.HL2 obtained by removing the low frequency noise by filtering the integrated value with a high pass filter (cutoff frequency fc) is obtained. The control device 2 adds θHL1 and θHL2 to obtain θHL (θHL = θHL1 + θHL2) = θ1.

  Here, the center-of-gravity position G of the vehicle 1 is the center of gravity of the entire vehicle 1 (excluding the left and right drive wheels 12) including the weight of the user when the user is seated on the seat 10. Say. When the user is seated on the seating portion 10, the overall center-of-gravity position G of the vehicle 1 is in the vicinity of the ground contact point 12c of the left and right drive wheels 12 in the front-rear direction. Here, θ1 and α are not large angles. Therefore, for convenience, sin θ1≈θ1 and cos (θ1 + α) ≈ (1− (θ1 + α)) ≈1 can be handled, so that linear approximation can be performed as in the following equation (2).

制御装置２が５輪モードから３輪モードへモードを移行させるにあたり、式（２）において、Ｍ１，Ｍ２，Ｒ，Ｊ１、Ｊ２、Ｌ，ｇはほぼ固定値であると推定できる。このため、式（２）によれば、ビークル１の全体の重心位置Ｇの傾斜角度θ１および路面傾斜角度αが増加するにつれて、左右の駆動輪１２に発生する駆動トルクＴを増加させる必要がある。このように駆動トルクＴを増加させれば、使用者の体重を含めたビークル１の全体（左右の駆動輪１２を除く）の重心位置Ｇが駆動輪１２の接地点１２ｃよりも前方（鉛直線Ｐ１よりも前方）から、後方（鉛直線Ｐ１よりも後方）に移動することができ、ビークル１を走行させつつ、前輪１５を路面９０から浮上させることができる。

When the control device 2 shifts the mode from the five-wheel mode to the three-wheel mode, it can be estimated that M1, M2, R, J1, J2, L, and g are substantially fixed values in the equation (2). Therefore, according to the equation (2), it is necessary to increase the drive torque T generated on the left and right drive wheels 12 as the inclination angle θ1 and the road surface inclination angle α of the center of gravity G of the entire vehicle 1 increase. . When the driving torque T is increased in this way, the center of gravity G of the entire vehicle 1 (excluding the left and right driving wheels 12) including the weight of the user is in front of the grounding point 12c of the driving wheels 12 (vertical line). The front wheel 15 can be lifted from the road surface 90 while moving the vehicle 1 from the front side to the rear side (backward from the vertical line P1).

  When the driving wheel 12, the front wheel 15 and the rear wheel 17 are in contact with the road surface 90, the road surface inclination angle α is set to an angle θHL (= θ1) described later and θ1 (when the vehicle 1 is present on the horizontal plane) Based on an angle θ1S defined by a line connecting the center of gravity position G and the axis center 12e of the drive wheel 12 and the vertical line P1), α≈θ1S−θHL is calculated. Here, the inclination angle θHL includes the output value of the rate gyro 52 attached around the pitch axis of the vehicle 1 (specifically, the shaft center 12e of the drive wheel 12) and the output value of the accelerometer 53 in the forward / backward direction. From this, it is obtained by calculation by the method shown in FIG. Accordingly, the rate gyro 52 and the accelerometer 53 are a road surface inclination angle sensor that detects the road surface inclination angle α and / or a pitch direction inclination angle that detects the pitch direction inclination angle θ1 of the center of gravity G of the vehicle 1 in the pitch direction. It can function as a detection sensor.

  Here, in consideration of the above equation (2), practically, if torque such as the following equation (3) is generated in the left and right drive wheels 12R, 12L, the five-wheel mode is switched to the three-wheel mode. A reliable mode transition can be realized. Therefore, when switching from the five-wheel mode to the three-wheel mode, the control device 2 calculates the drive torque T from calculation or a map. The driving torque T is a driving torque for switching from the five-wheel mode to the three-wheel mode. When torque equal to or greater than drive torque T is applied to drive wheels 12R and 12L, vehicle 1 is switched from the five-wheel mode to the three-wheel mode.

上記した式(３)において、Ｔｃは、摩擦等の補償トルクを示す。Ｋｐは、ピッチ方向傾斜角度θ１に関するフィードバックゲインを示す。θｔは、ビークル１の重心位置Ｇのピッチ方向の目標角度を示し、ビークル１に応じて予め設定されている固定値である。

In the above equation (3), Tc represents a compensation torque such as friction. Kp represents a feedback gain related to the pitch direction inclination angle θ1. θt indicates a target angle in the pitch direction of the gravity center position G of the vehicle 1, and is a fixed value set in advance according to the vehicle 1.

  Here, in the above equation (3), M1, M2, J1, J2, L, and R can be estimated as fixed values or almost fixed values. Therefore, according to the above equation (3), the drive torque T applied to the left and right drive wheels 12 is obtained based on the road surface inclination angle α and the pitch direction inclination angle θ1. Therefore, the driving torque T increases as the pitch direction inclination angle θ1 increases, and increases as the road surface inclination angle α increases. Therefore, when switching from the five-wheel mode to the three-wheel mode, the control device 2 obtains the pitch direction inclination angle θ1 and the road surface inclination angle α, sets the drive torque T based on the equation (3), and the control device 2 Feedback control is performed so that the drive torque applied to the drive wheels 12 becomes T. As a result, the vehicle can stably travel in the three-wheel mode.

  According to the above equations (1) to (3), as the pitch direction inclination angle θ1 increases, the road surface inclination angle α increases and the road surface 90 climbs up and the slope becomes steep. It is necessary to increase the generated driving torque T. Here, the drive torque T in the equations (1) to (3) is the sum of the left and right drive wheels 12. Therefore, when the vehicle 1 is switched from the five-wheel mode to the three-wheel mode, the drive torque of the left drive wheel 12 is T / 2 and the drive torque of the right drive wheel 12 is T / 2.

  The above-described formula (1X) corresponds to the above-described formula (1) when the road surface inclination angle α is zero. The above equation (2X) corresponds to the above equation (2) when the road surface inclination angle α is zero. When the road surface inclination angle α is 0, the above formula (3X) corresponds to the above formula (3). Thus, according to the equation (3X), when the road surface inclination angle α is 0, the control device 2 needs to increase the drive torque T generated on the left and right drive wheels 12 as the pitch direction inclination angle θ1 increases. There is. In the equation (3X), Tc represents a compensation torque such as friction as described above. Kp represents a feedback gain related to the pitch direction inclination angle θ1. θt indicates a target angle in the pitch direction of the gravity center position G of the vehicle 1, and is a fixed value set in advance according to the vehicle 1.

  * By the way, when the vehicle 1 is traveling in the five-wheel mode, an unexpected transition from the five-wheel mode to the three-wheel mode may occur. In addition, when a dangerous state occurs during the transition from the five-wheel mode to the three-wheel mode, a human intentional operation (such as a target speed command in the opposite direction) by the operation unit 14 (joystick or the like). On that occasion, the control device 2 outputs a command for stopping the driving of the left and right drive wheels 12 and outputs a command for lowering the rear wheel support bar 16 to improve the ground contact property of the rear wheel 17, thereby changing the mode. Return to 5-wheel mode. As a result, the vehicle 1 can stably return from the three-wheel mode to the five-wheel mode. Note that when switching from the five-wheel mode to the three-wheel mode, the above conditions (i) and (ii) are satisfied, but depending on the case, either one of (i) and (ii) Just as good.

* Control to switch from running in 3-wheel mode to 5-wheel mode (Control B)
When the vehicle 1 is traveling in the three-wheel mode, the rear wheel 17 may be lifted due to a movement of the center of gravity of the user sitting on the seating portion 10 or an unexpected factor. In this case, a rear wheel levitation signal is output to the control device 2 from the ground switch 50 that detects the grounding and levitation of the rear wheel 17 with respect to the road surface 90. Therefore, the control device 2 outputs a command to lower the rear wheel support bar 16 to the actuator 18. As a result, the control device 2 causes the rear wheel 17 to contact the road surface 90 and switches to the five-wheel mode where stable running can be achieved. In this case, when the mode switching button 141 of the operation unit 14 selects the three-wheel mode, the control device 2 performs control to shift to the three-wheel mode. Also in this case, in order to shift to the three-wheel mode, it is preferable to satisfy the conditions (i) and (ii) described above.

* In 3-wheel mode and the stable running torque control three-wheel mode and the fifth wheel mode for the respective 5-wheel mode to stabilize traveling vehicle 1, the driving torque of the right driving wheel 12R is maintained in T _R Thus, feedback control is performed independently on the drive wheels 12R and 12L so that the drive torque of the left drive wheel 12L is maintained at _TL . As a result, the rotational speed is controlled independently for the left and right drive wheels 12R, 12L. Here, T _R shown in Equation (4) shows the driving torque of the right driving wheel 12R for stable running. _TL shown in Equation (5) indicates the drive torque of the left drive wheel 12L for stable running.

ここで、式（４）（５）において、θRは右の駆動輪１２Ｒの回転角度を示す。θＬは左の駆動輪１２Ｌの回転角度を示す。回転角度θR，θＬの微分は角速度θ（ドット）R，θ（ドット）Ｌとなる。θ（ドット）R₋refは、右の駆動輪１２Ｒの角速度の目標値を示し、操作部１４の速度指令操作部１４２（ジョイスティック等）を介して使用者により随時変更される。また、θ（ドット）L₋refは、左の駆動輪１２Ｌの角速度の目標値を示し、操作部１４の速度指令操作部１４２（ジョイスティック等）を介して使用者により随時変更される。式（４）（５）において、θR等に付されているドットは時間による微分値を意味する。なお、θRは、右の駆動輪エンコーダ５５Ｒにより求められる。θLは、左の駆動輪エンコーダ５５Ｌにより求められる。θＲ（ドット）とθＬ（ドット）は計算機上での時間による差分により求められる。なお、θＲ（ドット）とθＬ（ドット）は、エンコーダではなくタコジェネレータ等の角速度センサにより求めても良い。

Here, in the equations (4) and (5), θR represents the rotation angle of the right drive wheel 12R. θL indicates the rotation angle of the left drive wheel 12L. The differential of the rotation angles θR and θL becomes the angular velocities θ (dots) R and θ (dots) L. θ (dot) R _- ref indicates a target value of the angular velocity of the right drive wheel 12R, and is changed as needed by the user via the speed command operation unit 142 (joystick or the like) of the operation unit 14. Θ (dot) L ₋ ref indicates a target value of the angular velocity of the left drive wheel 12L, and is changed by the user at any time via the speed command operation unit 142 (joystick or the like) of the operation unit 14. In the equations (4) and (5), the dots attached to θR and the like mean differential values with respect to time. Note that θR is obtained by the right drive wheel encoder 55R. θL is obtained by the left drive wheel encoder 55L. θR (dot) and θL (dot) can be obtained by the time difference on the computer. Note that θR (dot) and θL (dot) may be obtained by an angular velocity sensor such as a tachometer instead of an encoder.

According to equation (4) described above, the driving torque T _R of the right driving wheel 12R, for the right driving wheel 12R, the angular velocity .theta.R and (dot) the angular velocity target value .theta.R (dot) _- based on the difference between ref Alternatively, it is obtained based on the difference between the rotation angle θR and the integral value (time integral) of the angular velocity target value. Further, according to the above equation (5), the driving torque _TL of the left driving wheel 12L is the difference between the angular velocity θL (dot) and the angular velocity target value θ (dot) L ₋ ref for the left driving wheel 12. Or based on the difference between the rotation angle θL and the integrated value of the angular velocity target value (time integration). The time serving as a reference for time integration is based on a unit time arbitrarily set in advance and an operation time of the speed command operation unit 142 (joystick or the like).

In the above equations (4) and (5), the angular velocity feedback gain K _VR of the right driving wheel 12R, the angular velocity feedback gain K _VL of the left driving wheel 12L, the angular feedback gain K _PR of the right driving wheel 12R, left the angle feedback gain K _PL of the driving wheels 12L, respectively, experimentally sought appropriate, an arbitrary value. According to equation (4) (5) As described above, the driving torque T _R of the right drive wheel 12R is obtained based on the rotation angle θR of the right driving wheel 12. The drive torque _TL of the left drive wheel 12L is obtained based on the rotation angle θL of the left drive wheel 12.

  * By the way, when the vehicle 1 is traveling in the three-wheel mode, as shown in the right diagram of FIG. For this reason, when the vehicle 1 is suddenly stopped or retreated, or when the user moves the center of gravity, the vehicle body 12 tilts forward, or the rear wheel 17 attached to the rear wheel support bar 16 rises. There is a risk. Further, even when the vehicle 1 is traveling in the five-wheel mode, if the rear wheel support bar 16 is short and the vehicle starts suddenly on an inclined slope, the posture stability of the vehicle 1 is impaired, and the vehicle There is a risk that 1 will be excessively tilted backward.

  In consideration of the above circumstances, it is preferable to prevent sudden stop or reverse due to a sudden operation of the normal operation unit 14 (for example, joystick) when the vehicle 1 is traveling in the three-wheel mode. Therefore, the control device 2 applies a low-pass filter (filter unit) on the software to an input signal (speed command value) generated by operating the speed command operation unit 142 (for example, joystick) of the operation unit 14. As a result, only an input signal in a frequency range lower than the cut-off frequency f is input, and the vehicle 1 is suddenly stopped or retreated suddenly by a rapid operation of the speed command operation unit 142 of the operation unit 14. Suppresses excessive tilting of posture.

In other words, the control device 2 cuts a high-frequency component higher than the predetermined cutoff frequency f from the input signal (speed command signal) from the speed command operation unit 142 of the operation unit 14, and the speed command operation unit of the operation unit 14. A low frequency component lower than a predetermined cut-off frequency f is selected from the input signal by 142. That is, the control unit 2, the input signal (speed command signal of the speed command operating unit 142, the angular velocity target value for the right drive wheel 12R .theta.R (dot) _- ref, the angular velocity target value .theta.L (dots for the left drive wheel 12L) _- ref) is filtered by a low-pass filter. Thus speed target value of the right driving wheel 12R (the angular velocity target value .theta.R (dot) _- ref _- LP) and the left velocity target value of the driving wheels 12L (the angular velocity target value .theta.L (dot) _- ref _- LP) and the decide. Thus, the high frequency component higher than the predetermined cutoff frequency f is cut from the input signal (speed command signal) by the operation unit 14. For this reason, even when the speed command operation unit 142 of the operation unit 14 is suddenly operated, the vehicle 1 can be stably driven in, for example, the three-wheel mode.

FIG. 4 shows that the angular velocity target values of the right driving wheel 12R and the left driving wheel 12L are filtered by a low-pass filter. According to FIG. 4, the angular velocity target value .theta.R the right driving wheel 12R (dot) _- ref is filtered by the low-pass filter, the angular velocity target value .theta.R _- the LP _- ref. Further, the angular velocity target value .theta.L the left driving wheel 12L (dot) _- ref is filtered by the low-pass filter, the angular velocity target value .theta.L (dot) _- ref _- a LP.

* Adjustment control of cut-off frequency f In the above case, for the cut-off frequency f of filtering by the low-pass filter, the control device 2 obtains the road surface inclination angle α (α≈θ1S−θHL) with respect to the horizontal line, and the road surface inclination angle α ( In accordance with the magnitude of α≈θ1S−θHL), it is preferable to determine the filtering cutoff frequency f as follows. Here, when the vehicle 1 is moving forward in the three-wheel mode, if the vehicle 1 is suddenly input to increase the reverse speed by operating the speed command operation unit 142 (for example, joystick) of the operation unit 14, the vehicle 1 is The inertial force may cause excessive tilting forward, and the three-wheel mode may not be maintained (first case). Further, when the vehicle 1 is moving in three-wheel and five-wheel modes (including forward and reverse), if the operation unit 14 suddenly performs an input operation to increase the forward speed, the length of the bar 16 When the vehicle is short, the vehicle 1 may tilt excessively backward due to inertial force (second case).

  (I) In the first case, it is preferable to eliminate a rapid operation input from the speed command operation unit 142 of the operation unit 14 or the like. Therefore, the control device 2 determines the cut-off frequency f of the low-pass filter by calculation or a map based on the equation (6). Here, in Equation (6), f (= 1 / 2πT) represents the cutoff frequency of the low-pass filter with respect to the drive target value. fr indicates the reference cutoff frequency on a flat surface. kr (> 0) indicates a correction coefficient corresponding to the road surface inclination angle α. According to Equation (6), the cutoff frequency f changes according to the road surface inclination angle α. Specifically, when the road surface inclination angle α is increased and the road surface 90 is a steep uphill, the cutoff frequency f is increased as compared with the reference cutoff frequency on the flat ground. Thus, when traveling in the three-wheel mode, even when the speed command operation unit 142 of the operation unit 14 is suddenly operated, the traveling acceleration of the vehicle 1 is suppressed, and the vehicle 1 is excessively tilted forward. Can be prevented. In addition, it becomes that it becomes an uphill that road surface inclination-angle (alpha) becomes large with a positive value.

（ｉｉ）第２の場合には、式（７）に基づいて、制御装置２は演算またはマップなどによりカットオフ周波数ｆを決定する。

(Ii) In the second case, the control device 2 determines the cut-off frequency f by calculation or a map based on the equation (7).

ここで、式（７）において、ｆ(＝1／２πＴ)は、前方への駆動目標値に対するローパスフィルタのカットオフ周波数を示す。ｆｒは、平地上での上記基準カットオフ周波数を示す。ｋｆ（＞0）は、路面傾斜角度αに応じた補正係数を示す。式（７）によれば、カットオフ周波数ｆは路面傾斜角度α（≒θHL）に応じて変化する。具体的には、路面傾斜角度αが大きくなり、路面９０が勾配が大きな登り坂であれば、平地上での上記基準カットオフ周波数に比較して、カットオフ周波数ｆを低くする。これにより３輪状態および５輪状態で走行しているとき、ビークル１の走行加速度が抑制され、後方への過剰傾倒を阻止することができる。

Here, in Expression (7), f (= 1 / 2πT) represents a cutoff frequency of the low-pass filter with respect to the forward drive target value. fr indicates the reference cutoff frequency on a flat surface. kf (> 0) indicates a correction coefficient corresponding to the road surface inclination angle α. According to Equation (7), the cutoff frequency f changes according to the road surface inclination angle α (≈θHL). Specifically, when the road surface inclination angle α is increased and the road surface 90 is an uphill with a large gradient, the cutoff frequency f is set lower than the reference cutoff frequency on the flat ground. As a result, when the vehicle is traveling in the three-wheel state or the five-wheel state, the traveling acceleration of the vehicle 1 is suppressed, and excessive rearward tilting can be prevented.

* Control to shift to 5-wheel mode by lowering the rear wheel support bar 16 in 3-wheel mode driving (Control C)
Even if the vehicle 1 is controlled so as to suppress sudden stop and reverse of the vehicle 1 as described above, excessive sudden stop and reverse more than that, excessive change in the center of gravity G due to a change in human posture, etc. Unexpected circumstances may occur. In this case, it is assumed that the rear wheel 17 of the rear wheel support bar 16 floats above the road surface 90 during the three-wheel mode traveling. In this case, since the ground switch 50 (rear wheel state detection means) for detecting the grounding and / or rising of the rear wheel 17 is mounted on the rear wheel support bar 16, the road surface 90 is read by reading the signal from the ground switch 50. The floating of the rear wheel support bar 16 (the floating of the rear wheel 17 with respect to the road surface 90) is detected.

  Therefore, the control device 2 outputs a command to stop or decelerate the driving wheel 12 on the spot and outputs a command to lower the rear wheel support bar 16 to the position of the five-wheel mode. Migrate to The 5-wheel mode is excellent in running stability. For this reason, even if an excessive sudden stop or sudden reverse, an excessive change in the center of gravity G due to a change in the posture of the person, or an unexpected situation occurs, the vehicle 1 travels stably. In addition, not only the rear wheel 17 but also a sensor for detecting that the right driving wheel 12R, the left driving wheel 12L, the front wheel 15, and the rear wheel 17 are all grounded and / or floated with respect to the road surface. Can do.

(Embodiment 2)
Since the second embodiment has basically the same configuration and the same function and effect as the first embodiment, the drawings described in the first embodiment are applied mutatis mutandis. According to the present embodiment, in addition to the first embodiment, the control when the drive wheel 12 gets over the step 95 is performed. The grounding of both the drive wheel 12 and the front wheel 15 in the five-wheel mode is advantageous in running stability, but has a problem that the front wheel 15 collides with the step 95 and is difficult to get over. Increasing the diameter of the front wheel 15 makes it easier to get over the step 95, but there is a limit to increasing the diameter of the front wheel 15.

  FIGS. 5A to 5F show a sequence in which the driving wheel 12 of the vehicle 1 climbs over the step 95 and climbs by utilizing the three-wheel mode. When the vehicle 1 is traveling in the three-wheel mode, as shown in FIG. 5A, the front wheels 15 are floating from the road surface 90 although the drive wheels 12 and the rear wheels 17 are in contact with the road surface 90. . Therefore, when the vehicle 1 moves forward, the drive wheel 12 can be easily raised to the upper surface 96 of the step 95 (FIGS. 5A to 5C). Thereafter, for a step 95 that is low enough to be overcome by only the torque generated by the drive wheel 12, the drive wheel 12 is driven based on a forward command operation by the speed command operation unit 142 (for example, a joystick) of the operation unit 14. The upper surface 96 of the step 95 can be overcome only with normal generated torque.

  On the other hand, depending on the degree of the height of the upper surface 96 of the step 95 and the like, in the state shown in FIG. In this case, the driving torque of the driving wheel 12 is insufficient, and the driving wheel 12 slips. For such a step 95, the control device 2 performs the control D. That is, the control device 2 reads the speed command value of the speed command operation unit 142 of the operation unit 14 and the actual rotation speed of the drive wheels 12R and 12L. Then, based on the relationship between the excessive speed command value and the drive wheel rotational speed, that is, when the drive wheel rotational speed is slower than the excessive speed command value, it is determined that the step 95 cannot be overcome by the vehicle 1 as it is. Therefore, the control device 2 outputs a command to lower the rear wheel support bar 16 in the direction of arrow D (see FIG. 5B) to the actuator 18. Thereby, the rear wheel 17 attached to the rear wheel support bar 16 presses the road surface 90 in the direction of arrow F1 (see FIG. 5B). As a result, the reaction force causes the rear wheel 17 to generate an assist force that pushes up the vehicle 1. As a result of the assist force, the vehicle 1 can easily get over the step 95 even when the height of the upper surface 96 of the step 95 is high (see FIG. 5C).

* Slip detection of driving wheel 12 As shown in FIG. 2, the vehicle 1 includes an accelerometer 53 (detecting acceleration in the forward and backward directions of the vehicle 1) and a rate gyro 52 (angular velocity in the pitch direction of the vehicle 1). Detect) is installed. acc indicates the output value of the acceleration of the vehicle 1 obtained from the accelerometer 53. θacc is an output value of the drive wheel rotation angle sensor (that is, an output value of the rotary encoders 55 and 55L obtained by a difference with respect to time by a computer, and indicates the acceleration of the vehicle 1 in the forward and backward direction.

As shown in FIG. 6, the control device 2 considers the gravitational acceleration g based on the acceleration output acc of the vehicle 1 obtained from the accelerometer 53, and calculates a value of sin ⁻¹ (acc / g) (accelerometer (Corresponding to θHL obtained in step 53). Further, a value θHL1 from which high-frequency noise is removed is obtained by filtering the value with a low-pass filter (cut-off frequency fc). Further, the control device 2 obtains an integral value (corresponding to θHL obtained by the rate gyro 52) obtained by time-integrating the angular velocity θg (dot) that is an output value of the rate gyro 52, and obtains the integral value as a high-pass filter (cutoff frequency). According to fc), a value θHL2 from which noise in the low frequency range is removed by filtering is obtained. The control device 2 adds θHL1 and θHL2 to obtain θHL (θHL = θHL1 + θHL2).

  As described above, θHL1 based on the output value of the accelerometer 53 is filtered by a low-pass filter. On the other hand, θHL2 based on the output value of the rate gyro 52 is filtered by a high-pass filter. This is because the sensor characteristics of the accelerometer 53 whose accuracy is not sufficient in the high frequency range and the integrated value of the rate gyro 52 whose accuracy is not sufficient in the low frequency range are considered. Thereby, the detection accuracy of θHL can be increased in a low frequency range to a high frequency range. The cut-off frequency fc of the low-pass filter is the same value as the cut-off frequency of the high-pass filter.

  Here, when the driving wheel 12, the front wheel 15 and the rear wheel 17 are substantially in contact with the road surface 90, the angle θHL obtained by the accelerometer 53 and the rate gyro 52 corresponds to the actual road surface inclination angle α. (Α≈θHL). In this way, by using both of the two types of sensors, that is, the output value of the accelerometer 53 and the output value of the rate gyro 52, the actual road surface inclination angle α (α≈θHL) on which the vehicle 1 is traveling. Can be obtained as an angle θHL.

  Here, when the vehicle 1 is tilted in the pitch direction, the accelerometer 53 can detect acceleration according to the pitch direction tilt angle θ1 of the vehicle 1 due to the influence of gravitational acceleration. The accelerometer 53 determines the pitch direction inclination angle θ1 of the vehicle 1. The slip value of the drive wheel 12 is obtained based on the following formula (8).

そして、スリップ値がスリップ検知のための閾値ａｃｃ₋ｓを超えた場合には、制御装置２は、駆動輪１２がスリップしていると判定することができる。ここで、式（８）によれば、加速度計５３からの加速度出力ａｃｃ［m／sec^２］と車体ピッチ方向の重力加速度成分（gsinθHL）の和と駆動輪回転角加速度から求めた車体前後方向加速度θａｃｃとの差が大きいほど、また、θHL（つまりｓｉｎθHL）が大きいほど、スリップ値が高くなり、駆動輪１２がスリップしていると判定される。即ち、駆動輪１２のスリップの有無は、加速度計５３からの加速度出力，θHL，θａｃｃのうちの少なくとも一つの値に基づいて検知される。

When the slip value exceeds the threshold value acc _- s for slip detection, the control device 2 can determine that the drive wheel 12 is slipping. Here, according to the equation (8), the vehicle body longitudinal direction obtained from the sum of the acceleration output acc [m / sec ² ] from the accelerometer 53 and the gravitational acceleration component (gsinθHL) in the vehicle body pitch direction and the driving wheel rotation angular acceleration. It is determined that the larger the difference from the acceleration θacc and the larger θHL (that is, sin θHL), the higher the slip value and the drive wheel 12 is slipping. That is, the presence / absence of slip of the drive wheel 12 is detected based on the acceleration output from the accelerometer 53 and at least one value of θHL and θacc.

* When the drive wheel is slipping, control over the step 95 over the step 95 based on the assist force (Control E)
When slipping of the drive wheel 12 is detected based on the above-described slip determination algorithm (see equation (8)) in the state shown in FIG. The control device 2 determines that the drive torque of the drive wheels 12 is insufficient and the vehicle 1 cannot get over the step 95.

  Therefore, the control device 2 outputs a command to raise the rear wheel support bar 16 in the direction of arrow U (see FIG. 5C) 4) to the actuator 18. As a result, the left and right drive wheels 12 shown in FIG. 5B descend due to gravity and reliably contact the road surface 90, so that the slip of the drive wheels 12 is released. Thereafter, the control device 2 outputs a command to lower the rear wheel support bar 16 in the direction of arrow D to the actuator 18 again. Accordingly, the rear wheel 17 attached to the rear wheel support bar 16 presses the road surface 90 again while rotating the driving wheel 12. For this reason, based on the reaction force, an assist force (an assist force over which the drive wheel 12 gets over the step 95) by the rear wheel support bar 16 and the rear wheel 17 is generated. Since the rear wheel 17 generates the assist force while rotating the drive wheel 12 in this way, the drive wheel 12 can ride on the upper surface 96 of the step 95 (see FIG. 5D).

* Control of return of the reference position of the rear wheel support bar 16 after the climb of the step 95 (control F)
In the state shown in FIG. 5D, the driving wheel 12 has moved to the upper surface 96 of the step 95, so that the driving wheel 12 is lifted to the upper surface 96 of the step 95. In this case, based on the pitch direction inclination angle θ1 of the vehicle 1 obtained by the accelerometer 53 and the rate gyro 52, the control device 2 has completed the transition of the vehicle 1 to the upper surface 96 of the step 95 (that is, the driving wheel). 12 is present on the upper surface 96 of the step 95).

  Here, if the pitch direction inclination angle θ1 is within a predetermined angle (for example, 0 degree), the vehicle 1 can be estimated to be almost horizontal, and the control device 2 indicates that the vehicle 1 exists on the upper surface 96 of the step 95, The control device 2 can detect that the transition to 96 has been completed. Then, as shown in FIG. 5F, the control device 2 lowers the rear wheel support bar 16 in the direction of the arrow D, so that the reference position of the rear wheel support bar 16 (the rear wheel support bar 16 in the five-wheel mode). To the actuator 18, the rear wheel 17 is grounded to the upper surface 96 of the step 95. As a result, the vehicle 1 returns to the five-wheel mode and stably travels on the upper surface 96 of the step 95 in the five-wheel mode (see (f) of FIG. 5).

* Slip detection of the drive wheel 12 when descending the step 95 in the five-wheel mode traveling, and slip release control by the rear wheel support bar 16 (control G)
FIG. 7 shows a sequence in the case where the vehicle 1 travels on the upper surface 96 of the step 95 in the five-wheel mode, and further moves down to the road surface 90 after descending the upper surface 96 of the step 95. In this case, according to the state shown in FIG. 7D, since the rear wheel 17 contacts the upper surface 96 of the step 95 and the front wheel 15 contacts the road surface 90, the driving wheel 12 is connected to the road surface 90 and the upper surface of the step 95. There is a possibility that the driving wheel 12 slips and the driving force of the driving wheel 12 is not transmitted to the road surface 90. In this case, there is a risk of hindering the traveling of the vehicle 1. Therefore, the control device 2 detects the slip of the drive wheel 12 based on the slip detection algorithm (see Expression (8)) of the drive wheel 12 as described above. Then, the control device 2 outputs a command for raising the rear wheel 17 and the rear wheel support bar 16 in the arrow U direction (see FIG. 7D) to the actuator 18 until the drive wheel 12 no longer slips. Thereby, the grounding property of the drive wheel 12 is improved. If the slip of the drive wheel 12 does not occur, the vehicle 1 can move forward with the torque of the drive wheel 12. Therefore, when the control device 2 detects that the slip of the drive wheel 12 has been released, the control device 2 outputs a command for lowering the rear wheel support bar 16 in the direction of arrow D to the actuator 18, and the rear wheel 17 of the rear wheel support bar 16. Is lowered and the rear wheel 17 is returned to the reference position in the five-wheel mode. In this way, even when slipping of the drive wheels 12 occurs when the vehicle 1 descends the step 95, the drive wheels 12 of the vehicle 1 are excellent if the rear wheel support bar 16 and the rear wheels 17 are raised. The road surface 90 can be grounded from the upper surface 96 of the step 95. Note that the vehicle 1 that has descended from the upper surface 96 of the step 95 can travel on the road surface 90 in the five-wheel mode.

* Control that prevents excessive tilting of the vehicle 1 to the rear when the vehicle travels over a slope 95 or over a step 95. If the drive torque of the drive wheel 12 is too large during a slope travel or over a step 95, the vehicle 1 May tilt excessively backwards. It is preferable to address this. In this case, as described above, the road surface inclination angle α (≈θHL) is obtained by the control device 2 by combining the output value of the rate gyro 52 and the output value of the accelerometer 53. In consideration of the road surface inclination angle α (including the inclination of the step 95 when stepping over the step 95), it is preferable to prevent the vehicle 1 from falling backward when traveling on a slope or stepping over the step 95. Here, if the torque of the drive wheel 12 is too large, the vehicle 1 may be excessively tilted backward. Therefore, the control device 2 performs torque suppression control that suppresses excessive torque of the drive wheels 12 when the vehicle 1 is traveling in the five-wheel mode. In this case, the maximum torque Tlimit of the drive wheel 12 (the total torque given to the drive wheels 12R and 12L) is determined from the mechanism of the vehicle 1 based on the equation (9). When the control device 2 is traveling in the five-wheel mode, the drive torque is feedback-controlled so as not to exceed the maximum torque Tlimit when the drive torque is applied to the drive wheels 12.

ここで、図８に示すように、Ｐ３は、重心位置Ｇを通るような路面９０に対する路面垂直線を示す。Ｌｂは、路面垂直線Ｐ３と後輪１７の接地点との最短の距離を示す。Ｌａは、後輪１７の接地点と駆動輪１２の中心１２ｃとの距離を示す。Ｒは駆動輪１２の中心１２ｃからの半径を示す。上記した式（９）において、Ｒ，Ｌｂ，Ｌａ，Ｍ１，Ｊ１は固定値またはほぼ固定値とみなし得る。このため、上記した式（９）によれば、路面傾斜角度αが小さくてｃｏｓαの値（路面９０がほぼ水平のとき、ｃｏｓα≒１）が大きいと、最大トルクＴlimitは大きくなる。また、路面傾斜角度αが大きく、ｃｏｓαの値が小さくなると、最大トルクＴlimitは小さくなる。また、距離Ｌｂが増加すると、最大トルクＴlimitは大きくなる。更に距離Ｌａが増加すると、最大トルクＴlimitは小さくなる。但しＬｂが増加すると、Ｌａも増加する。上記したように駆動輪１２に与えられる駆動トルクが最大トルクＴlimitを越えないように、制御装置２はモータ１３Ｒ，１３Ｌをフィードバック制御している。このため斜面走行時、段差９５の乗り越え時などにおいても、ビークル１の姿勢が安定し、後方へ過剰に傾くことが防止される。

Here, as shown in FIG. 8, P <b> 3 indicates a road surface vertical line with respect to the road surface 90 passing through the gravity center position G. Lb indicates the shortest distance between the road surface vertical line P3 and the ground contact point of the rear wheel 17. La indicates the distance between the ground contact point of the rear wheel 17 and the center 12c of the drive wheel 12. R represents a radius from the center 12c of the drive wheel 12. In the above equation (9), R, Lb, La, M1, and J1 can be regarded as fixed values or almost fixed values. Therefore, according to the above equation (9), when the road surface inclination angle α is small and the value of cos α (cos α≈1 when the road surface 90 is substantially horizontal) is large, the maximum torque Tlimit increases. When the road surface inclination angle α is large and the value of cos α is small, the maximum torque Tlimit is small. Further, as the distance Lb increases, the maximum torque Tlimit increases. As the distance La further increases, the maximum torque Tlimit decreases. However, when Lb increases, La also increases. As described above, the control device 2 performs feedback control of the motors 13R and 13L so that the drive torque applied to the drive wheels 12 does not exceed the maximum torque Tlimit. For this reason, even when traveling on a slope or overcoming the step 95, the posture of the vehicle 1 is stabilized and it is prevented that the vehicle 1 is excessively tilted backward.

(Embodiment 3)
9 to 11 show the third embodiment. This embodiment is applied to the electric wheelchair 1B. The present embodiment has the same configuration and effect as the first embodiment. Parts common to the first embodiment are denoted by common reference numerals. As shown in FIG. 9, a wheelchair 1 </ b> B as a vehicle includes a vehicle body 11 having a seating portion 10 on which a user is seated, left and right rotatable drive wheels 12 attached to the vehicle body 11, and drive wheels 12. A driving wheel motor 13 as a driving source for rotational driving, an operation unit 14 for controlling driving of the driving wheel motor 13, and rotatable left and right front wheels 15 mounted on the vehicle body 11 in front of the driving wheel 12. A rear wheel support bar 16 as a rear wheel support member attached to the vehicle body 11, a rotatable rear wheel 17 attached to a front end portion 16e of the rear wheel support bar 16 via a holding portion 19, and a rear wheel support An actuator 18 is provided that raises and lowers the bar 16 with respect to the road surface 90 to ground and float the rear wheel 17 with respect to the road surface 90. As shown in FIG. 9, the vehicle body 11 includes a footrest 111 that supports a leg of a user seated on the seating portion 10, an armrest 112 that supports the arm of the user seated on the seating portion 10, and an assistant An operation lever 113 that is operated from the rear side of the wheelchair 1B is provided. The seating portion 10 includes a seat portion 10a that supports the user's waist and a backrest portion 10c that supports the user's back.

  As shown in FIG. 9, the front end portion 16 e of the rear wheel support bar 16 extends rearward from the ground contact point 12 c of the driving wheel 12 and is positioned rearward from the outermost peripheral surface 12 p of the driving wheel 12. Yes. A base end portion 16f of the rear wheel support bar 16 is attached to a mounting frame 11x below the seating portion 10 in the vehicle body 11 so as to be swingable in the vertical direction by a pivot portion 11k (pivot shaft). Therefore, the rear wheel support bar 16 and the rear wheel 17 can swing in the vertical direction (arrow U direction, arrow D direction) with the pivotal support portion 11k as the center of rotation. Accordingly, the assisting force by the rear wheel 17 is given around the pivot 11k.

  The base end portion 16f of the rear wheel support bar 16 is attached to the rear of the shaft center 12e of the drive wheel 12, but is not limited thereto. The drive wheel 12 includes a right drive wheel 12R and a left drive wheel 12L.

  As shown in FIG. 9, the actuator 18 includes an actuator main body 180 and a moving body 182 that is provided on the actuator main body 180 and moves the rear wheel 17 in a direction in which the rear wheel 17 is grounded with respect to the road surface 90 and a direction in which the rear wheel 17 is lifted. One end portion 180a of the actuator main body 180 is pivotally supported and attached to the attachment portion 115 of the vehicle body 11 so as to be movable up and down along a vertical direction by a pivot portion 116 (a pivot shaft). The moving body 182 protrudes from the other end portion 180c of the actuator main body 180 toward the road surface 90 so as to be extendable and contractable, and swings at a middle portion in the length direction of the rear wheel support bar 16 via a pivot portion 185 (a pivot shaft). It is pivotally supported. When the rear wheel 17 is in contact with the road surface 90, the grounding point 17 c of the rear wheel 17 is located behind the grounding point 12 c of the driving wheel 12 and is located behind the rearmost end 12 r of the driving wheel 12. .

  Although not shown, the actuator 18 is electrically driven and has a screw structure including a female screw portion and a male screw portion that is screwed into and retracted from the female screw portion. With the female screw portion and the male screw portion, the moving body 182 moves linearly forward in the direction of arrow D (the direction of contact with the road surface) relative to the actuator main body 180, or moves straight back in the direction of arrow U (the direction of rising from the road surface). You can make it.

  As shown in FIG. 10, a single rear wheel support bar 16 is provided so as to be located in the central region of the vehicle body 11 in the width direction (direction perpendicular to the forward and backward direction, direction K1). As with the rear wheel support bar 16, a single actuator 18 connected to the rear wheel support bar 16 is provided so as to be located in the central region in the width direction (K1 direction) of the vehicle body.

  As can be understood from FIG. 9, when the moving body 182 advances from the actuator main body 180 toward the road surface 90 in the direction of arrow D (the direction of contact with the road surface, downward), the front end portion 16 e of the rear wheel support bar 16 is moved to the road surface 90. The rear wheel 17 can be moved (lowered) in a direction in which the rear wheel 17 is brought into contact with the road surface 90. On the other hand, when the moving body 182 moves in the direction approaching the actuator body 180, that is, in the direction of arrow U (floating direction from the road surface, upward) and moves away from the road surface 90, the front end portion of the rear wheel support bar 16 The rear wheel 17 can be lifted (raised) from the road surface 90 by relatively lifting the 16e away from the road surface 90. However, even if the front end portion 16e of the rear wheel support bar 16 is relatively lifted in the direction away from the road surface 90, the rear wheel 17 may remain in contact with the road surface 90 when the vehicle 1 tilts backward. .

  FIGS. 11A and 11B show the vicinity of the rear wheel 17. As shown in FIGS. 11 (a) and 11 (b), the arm portion 19x of the holding portion 19 for holding the rear wheel 17 is swung up and down by the pivot shaft 19w at the front end portion 16e of the rear wheel support bar 16. It is provided to be movable. The holding portion 19 is provided to be rotatable in the left-right direction (arrow K3 direction) by a bearing 17a around an axis P5 along the vertical direction, and is provided rotatably at a lower portion of the rear wheel holder 17b and the rear wheel holder 17b. A horizontal axle 17c for the rear wheel 17 and a spring 17e for buffering an impact at the time of ground contact are provided. A contact switch 50 formed by a limit switch for detecting the grounding and / or the rising of the rear wheel 17 with respect to the road surface 90 is provided. The contact switch 50 is provided at the front end portion 16 e of the rear wheel support bar 16. When the rear wheel 17 is grounded, the arm portion 19x provided on the holding portion 19 operates the contact switch 50. However, the present invention is not limited to this, and the grounding and / or floating of the rear wheel 17 may be detected based on the inclination angle of the rear wheel support bar 16.

(Embodiment 4)
FIG. 12 shows a fourth embodiment. This embodiment is applied to an electric wheelchair 1C. The present embodiment has the same configuration and effect as the first embodiment. Parts common to the first embodiment are denoted by common reference numerals. As shown in FIG. 12, the wheelchair 1 </ b> C includes a rear wheel support bar 16 as a rear wheel support member attached to the vehicle body 11, and a rotation attached to a front end portion 16 e of the rear wheel support bar 16 via a holding portion 19. A possible rear wheel 17 and a torsion coil spring 188 as an actuator for grounding and floating the rear wheel 17 with respect to the road surface 90 by raising and lowering the rear wheel support bar 16 with respect to the road surface 90 are provided. The torsion coil spring 188 functions as a biasing member that biases the rear wheel 17 downward (arrow D direction, grounding direction) toward the road surface 90 via the base end portion 16f of the rear wheel support bar 16. The grounding property with respect to the road surface 90 of the wheel 17 is enhanced. When the front wheel 15 rises above the road surface 90 and enters the three-wheel mode, the center of gravity position G is behind the contact point 12c of the drive wheel 12, so the vehicle body 11 is tilted backward. In this case, the rear wheel support bar 16 hits the stopper portion 11 s attached to the frame 11 x of the vehicle body 11. Therefore, it is possible to suppress the rear wheel support bar 16 from rising further in the arrow U direction. Thus, the torsion coil spring 188 operates the rear wheel support bar 16 toward the road surface 90 to ground the rear wheel 17 with respect to the road surface 90, or resists the spring force of the torsion coil spring 188 in the arrow U direction (road surface). And a function of floating in a direction away from 90). The biasing member such as a coil spring, a leaf spring, or a disc spring is not limited to the torsion coil spring 188.

(flowchart)
* FIG. 13 illustrates a flowchart of the control A for switching from the five-wheel mode to the three-wheel mode when the vehicle 1 is traveling. The flowchart is an example, and the present invention is not limited to this. First, the control device 2 reads the outputs of various sensors and switches (including the mode switching button 141, the speed command operation unit 142, and the encoders 55R and 55L) (step S102). It is determined whether or not the mode switching button 141 has been switched from the five-wheel mode to the three-wheel mode (step S104). If the mode is switched to the three-wheel mode (YES in step S104), the operation time T of the mode switching button 141 is operated for a certain time Tc or more (YES in step S106), and the forward travel speed V of the vehicle 1 is set. If the condition that the speed Vc is equal to or higher than the speed Vc (YES in Step S108), and the target value Vtarget of the forward speed by the speed command operation unit 142 (for example, joystick) is equal to or higher than a certain value Vtc (YES in Step S110), The driving torque T of the driving wheel 12 is calculated and output to the motor drivers 131 and 132, and the operation of lifting the bar 16 together with the rear wheel 17 is performed (step S112). This switches to the three-wheel mode. Even if the operation time T of the mode switching button 141 is operated for a certain time Tc or longer (YES in step S106), the forward traveling speed V is not equal to or higher than the set speed Vc (NO in step S108), and a speed command operation unit If the condition that the target value Vtarget of the forward speed by 142 (for example, a joystick) is not equal to or higher than the constant value Vtc (NO in step S110) is satisfied, the mode is not switched from the five-wheel mode to the three-wheel mode.

  * FIG. 14 illustrates a flowchart of control B for switching from the three-wheel mode to the five-wheel mode. The flowchart is an example, and the present invention is not limited to this. First, the control device 2 reads the outputs of various sensors and switches (including the mode switching button 141, the ground switch 50, the encoders 55R, 55L, etc.) (step S202). It is determined whether or not the mode switching button 141 has been switched to the five-wheel mode (step S204). If the mode is switched to the five-wheel mode (YES in step S204), it is determined whether or not the rear wheel 17 is lifted from the road surface 90 (step S206). If the rear wheel 17 has been lifted from the road surface 90 (YES in step S206), the bar 16 is lowered to bring the rear wheel 17 into contact with the road surface 90 and switched to the five-wheel mode to improve running stability (step S208). .

  * FIG. 15 illustrates a flowchart of the control C. The flowchart is an example, and the present invention is not limited to this. First, the control device 2 reads the outputs of various sensors and switches (including the mode switching button 141, the ground switch 50, etc.) (step S302). It is determined whether or not the vehicle 1 is in the three-wheel mode and the rear wheel 17 is lifted from the road surface 90 (step S304). If the rear wheel 17 is lifted from the road surface 90 (YES in step S304), the stability of the posture of the vehicle 1 is impaired, so that a command to stop or decelerate the drive wheel 12 is output to the motors 13R and 13L. The bar 16 is lowered to ground the rear wheel 17 on the road surface 90 (step S306).

  * FIG. 16 shows a flowchart of the control D that is executed when overcoming the step. The flowchart is an example, and the present invention is not limited to this. First, the control device 2 reads output values of various sensors and switches (speed command value of the speed command operation unit 142, rotation speed of the driving wheels of the encoders 55R and 55L) (step S402). Then, based on the relationship between the excessive speed command value and the driving wheel rotation speed, it is determined whether or not the level difference 95 cannot be overcome (step S404). If the step 95 cannot be overridden (YES in step S404), the control device 2 generates a rear wheel assist force for lowering the rear wheel support bar 16 in order to assist overstepping (step S406).

  * FIG. 17 illustrates a flowchart of the control E executed at the time of overcoming the step. The flowchart is an example, and the present invention is not limited to this. First, the control device 2 reads the outputs of various sensors and switches (including the mode switching button 141, the ground switch 50, the rate gyro 52, and the accelerometer 53) (step S502). It is determined whether or not the vehicle 1 is traveling in the three-wheel mode and is moving over a step (step S504). If the step-over operation is in progress (YES in step S504), it is determined whether or not the drive wheel 12 has slipped (step S506). If slip of drive wheel 12 has occurred (YES in step S506), bar 16 is raised for a predetermined time to raise rear wheel 17 (step S508). Thereby, the grounding property of the drive wheel 12 is improved. Thereafter, in order to assist overcoming the step, the bar 16 is lowered to lower the rear wheel 17 to exert the rear wheel assist force (step S510).

  * FIG. 18 exemplifies a flowchart of this control F that is executed at the time of overcoming the step. The flowchart is an example, and the present invention is not limited to this. First, the control device 2 reads the outputs of various sensors and switches (including the mode switching button 141, the ground switch 50, the rate gyro 52, and the accelerometer 53) (step S602). It is determined whether or not the vehicle 1 has moved to the upper surface 96 of the step 95 (step S604). If the vehicle 1 moves to the upper surface 96 of the step 95 and is horizontal (YES in step S604), the bar 16 is lowered and returned to the reference position (step S606). This returns to the five-wheel mode. As a result, the upper surface 96 of the step 95 can be driven in the five-wheel mode. Here, the reference position of the rear wheel support bar 16 means a use position of the rear wheel support bar 16 in the five-wheel mode.

  * FIG. 19 illustrates a flowchart of the control G. The flowchart is an example, and the present invention is not limited to this. First, the control device 2 reads the outputs of various sensors and switches (including the mode switching button 141, the ground switch 50, the rate gyro 52, and the accelerometer 53) (step S702). It is determined whether or not the vehicle 1 is descending the step 95 (step S704). If the vehicle 1 is descending the step 95 (YES in step S704), the presence / absence of slip of the drive wheel 12 is detected by the above-described slip determination algorithm (step S706). If a slip of the drive wheel 12 is detected (YES in step S706), the bar 16 and the rear wheel 17 are raised for a predetermined time to lower the drive wheel 12 and improve the grounding performance of the drive wheel 12 (step S708). If slip cancellation of the drive wheel 12 is detected (YES in step S710), the bar 16 and the rear wheel 17 are lowered (step S712).

(Other)
According to the first embodiment described above, the operation unit is switched to the second mode, the traveling speed in the forward direction is not less than the set speed, and the speed target value by the operation unit in the forward direction is not less than a certain value. When the condition is satisfied, the control device performs control to switch from the first mode to the second mode. However, the control device is not limited to this, and when the operation unit is switched to the second mode, the control device May be controlled to switch from the first mode to the second mode. Personal vehicles are not limited to wheelchairs where elderly people, persons with disabilities, etc. are boarded, but simple vehicles that can carry one or more healthy persons (two persons, etc.) at venues such as expositions, stages, and amusement parks. It can also be applied to vehicles. The present invention is not limited to the above-described embodiments, and can be implemented with appropriate modifications within a range not departing from the gist.

  The following technical idea can also be grasped from the above idea.

  (Additional Item 1) A vehicle body having a seating portion on which a user is seated, drive wheels attached to the left and right sides of the vehicle body, a drive source attached to the vehicle body for rotationally driving the drive wheels, and the drive source An operation unit that controls the driving of the vehicle, a front wheel that is located in front of the drive wheel and is attached to the vehicle body, a rear wheel support member that is attached to the vehicle body, and a rear wheel support member that is attached to the road surface. A rear wheel located on the rear side of the ground point of the driving wheel when contacting the road surface, and a first mode in which the vehicle travels with at least the driving wheel and the front wheel; and the driving with the front wheel floating And a control device capable of switching between a second mode in which the vehicle travels while the wheel and the rear wheel are in contact with the road surface. In this case, the first mode traveling and the second mode traveling can be switched. An actuator that operates the rear wheel support member to ground and float the rear wheel with respect to the road surface may or may not be provided.

  (Additional Item 2) In Additional Item 1, the front wheels are provided on the left and right sides of the vehicle body, the rear wheels are singular, and the first mode includes the left and right drive wheels, the left and right front wheels, and the rear A personal vehicle characterized in that it is a five-wheel mode that travels on wheels, and the second mode is a three-wheel mode that travels on the left and right drive wheels and the rear wheels while levitating the left and right front wheels.

  (Additional Item 3) In Additional Item 1 or 2, in the first mode, the vehicle is running such that the position of the center of gravity of the vehicle including the weight of the user is located forward of the ground point of the driving wheel, When the control device switches from the first mode to the second mode (front wheel floating mode), the position of the center of gravity of the vehicle including the weight of the user is located behind the ground point of the driving wheel. A personal vehicle characterized by performing control to generate a driving torque in the driving wheel. Thereby, it is possible to switch from the first mode running (front wheel contact mode) to the second mode running (front wheel floating mode).

  (Additional Item 4) In Additional Item 3, when switching from the first mode to the second mode, the driving torque applied to the driving wheel is T, and the pitch direction of the gravity center position of the personal vehicle including the weight of the user When the inclination angle of the vehicle is θ1, the control device controls the drive torque T generated in the drive wheels based on the pitch direction inclination angle θ1 of the vehicle body. In this case, if the pitch direction inclination angle θ1 of the vehicle body is detected and a driving torque T corresponding to the pitch direction inclination angle θ1 is applied to the driving wheels, the second mode (front wheel floating mode) traveling can be maintained. Further, when the pitch direction inclination angle θ1 decreases, if the driving torque T generated on the driving wheel is decreased, the vehicle can stably travel in the second mode (front wheel floating mode). Similarly, when the pitch direction inclination angle θ1 increases, if the driving torque T generated on the driving wheel is increased, the vehicle can stably travel in the second mode (front wheel floating mode).

  (Additional Item 5) In Additional Item 3, a driving torque applied to the driving wheel when switching from the first mode to the second mode is T, a road surface inclination angle on the road surface on which the driving wheel travels is α, and When the inclination angle in the pitch direction of the gravity center position of the personal vehicle including the weight of the user is θ1, the control device drives the driving when the pitch direction inclination angle θ1 and / or the road surface inclination angle α of the vehicle body increase. A personal vehicle characterized by performing control to increase a driving torque T generated in a wheel. In this case, it is possible to switch from the first mode (front wheel contact mode) to the second mode (front wheel floating mode).

  (Additional Item 6) In one of the additional items 1 to 5, a traveling speed detection unit that detects a traveling speed of the personal vehicle and / or a speed target value of the traveling speed in the forward direction of the personal vehicle is set. Target travel speed setting means is provided, the operation unit is switched to the second mode, the forward travel speed is equal to or higher than the set speed, and the forward speed target value by the operation unit is constant. The personal vehicle is characterized in that when at least one condition of being equal to or greater than a value is satisfied, the control device performs control to switch from the first mode to the second mode. In this case, it is possible to switch from the first mode (front wheel contact mode) to the second mode (front wheel floating mode).

  (Additional Item 7) The personal vehicle according to any one of Additional Items 1 to 6, further comprising a rear wheel state detection unit configured to detect grounding and floating of the rear wheel with respect to the road surface. In this case, it is possible to detect the grounding and flying of the rear wheel. Therefore, it is possible to contribute to ensuring stable traveling in the first mode traveling, overcoming a step, and the like.

  The present invention can be used for personal vehicles represented by electric wheelchairs and the like.

(A) is a side view which shows typically the state which drive | works in 5 wheel mode, (b)-(d) is a side view which shows typically the form which switches 5 wheel mode and 3 wheel mode. . It is a figure which shows a control system typically. It is a figure which shows the parameter at the time of drive | working in 5 wheel mode. It is a figure which shows the low-pass filtering of the angular velocity target value of both wheels. It is a side view which shows a level | step difference rising sequence typically. It is a figure which shows fusion of the low-pass filtered value of the output value of an accelerometer, and the high-pass filtered value of the rate gyro integrated value. It is a side view which shows a level | step difference descending sequence typically. It is a figure which shows the parameter at the time of drive | working in 5 wheel mode. It is a side view which shows a wheelchair. It is a rear view which shows a wheelchair. (A) is a rear view showing the vicinity of the rear wheel, and (b) is a side view showing the vicinity of the rear wheel. It is a side view which shows a wheelchair. It is a flowchart which shows the control A which switches from 5 wheel mode to 3 wheel mode when the vehicle is drive | working. It is a flowchart which shows the control B which switches from 3 wheel mode to 5 wheel mode. It is a flowchart which shows the control C. It is a flowchart which shows the control D. 5 is a flowchart showing a control E. It is a flowchart which shows the control F. It is a flowchart which shows the control G.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 is a vehicle, 10 is a seating part, 11 is a vehicle body, 12 is a drive wheel, 12R is a right drive wheel, 12L is a left drive wheel, 13 is a drive wheel motor (drive source), 14 is an operation part, 15 is a front wheel , 16 is a rear wheel support bar (rear wheel support member), 17 is a rear wheel, 18 is an actuator, 2 is a control device, 23 is a CPU, 13R is a right drive wheel motor (first drive source), and 13L is a left Drive wheel motor (second drive source), 14 is an operation unit, 141 is a mode switch button 141 (mode switch), 142 is a speed command operation unit, 50 is a ground switch (rear wheel state detection means), and 52 is a rate gyro. , 53 is an accelerometer, 55R is a right driving wheel encoder (traveling speed detecting means), 55L is a left driving wheel encoder (traveling speed detecting means), 57 is a position sensor, and 142 is a speed command operation unit (target travel speed setting). hand ) Shows the.

Claims (13)

A vehicle body having a seating portion on which a user is seated;
Driving wheels attached to the left and right of the vehicle body;
A drive source attached to the vehicle body for driving the drive wheels to rotate;
An operation unit for controlling the drive of the drive source;
A front wheel attached to the vehicle body in front of the drive wheel;
A rear wheel support member attached to the vehicle body;
A rear wheel that is attached to the rear wheel support member so as to be able to be grounded on a road surface, and is located on the rear side of the ground point of the driving wheel when grounded on the road surface;
An actuator that operates the rear wheel support member to ground and float the rear wheel with respect to the road surface;
The front wheels are provided on the left and right sides of the vehicle body, and the rear wheels are single.
The first mode is a mode in which the left and right drive wheels, the left and right front wheels and the rear wheels travel, and the second mode is a mode in which the left and right front wheels float and the left and right drive wheels and the rear wheels travel. It has a control device that can switch between modes,
Travel speed detection means for detecting the travel speed of the personal vehicle and / or target travel speed setting means for setting a speed target value of the travel speed in the moving direction of the personal vehicle are provided,
At least one of the conditions that the operation unit is switched to the second mode, the traveling speed in the forward direction is not less than a set speed, and the speed target value in the forward direction by the operation unit is not less than a certain value. Is satisfied,
The personal vehicle, wherein the control device performs control to switch from the first mode to the second mode. A vehicle body having a seating portion on which a user is seated;
Driving wheels attached to the left and right of the vehicle body;
A drive source attached to the vehicle body for rotationally driving the drive wheel;
An operation unit for controlling the drive of the drive source;
A front wheel attached to the vehicle body in front of the drive wheel;
A rear wheel support member attached to the vehicle body;
A rear wheel that is attached to the rear wheel support member so as to be able to be grounded on a road surface, and is located on the rear side of the ground point of the driving wheel when grounded on the road surface;
An actuator that operates the rear wheel support member to ground and float the rear wheel with respect to the road surface;
A control device capable of switching between at least a first mode that travels with the driving wheel and the front wheel and a second mode that travels while the driving wheel and the rear wheel are in contact with the road surface with the front wheel floating; Comprising
Travel speed detection means for detecting the travel speed of the personal vehicle and / or target travel speed setting means for setting a speed target value of the travel speed in the moving direction of the personal vehicle are provided,
At least one of the conditions that the operation unit is switched to the second mode, the traveling speed in the forward direction is not less than a set speed, and the speed target value in the forward direction by the operation unit is not less than a certain value. Is satisfied,
The personal vehicle , wherein the control device performs control to switch from the first mode to the second mode . In Claim 1 or 2 , in the 1st mode, it runs so that the gravity center position of the personal vehicle including the weight of the user may be located ahead of the grounding point of the driving wheel,
When the control device switches from the first mode to the second mode, the control device applies a driving torque such that the position of the center of gravity of the personal vehicle including the weight of the user is located behind the ground point of the driving wheel. A personal vehicle characterized by performing control applied to a drive wheel. In claim 3 , when the driving torque applied to the driving wheel is T, and the inclination angle of the personal vehicle including the weight of the user with respect to the pitch axis is θ1,
It said controller, when switching from said first mode to said second mode, before the Ki傾 oblique angle θ1 increases, personal vehicles and performing control for increasing the drive torque T to be applied to the driving wheels. In claim 3 or 4 , when the road surface inclination angle on the road surface on which the driving wheel travels is α,
When switching from the first mode to the second mode, the control device performs control to increase the driving torque T applied to the driving wheels when the road surface inclination angle α increases. In one of claims 1 to 5, a personal vehicle, characterized in that it comprises a wheel state detecting means after detecting a ground and / or floating of the rear wheel against the road. In one of claims 1 to 6, wherein the control device is characterized in that it comprises a low-pass filter means for cutting a high frequency component than a predetermined cutoff frequency of the input signal by the operation unit Personal vehicle. In one of claims 1 to 6, wherein the controller, at the time when the running in the second mode, when the rear wheel of the rear wheel support member is floated from the road surface, the drive wheel A personal vehicle characterized by performing at least one of an operation of decelerating or stopping the rotation speed and an operation of operating the rear wheel support member to lower the rear wheel toward the road surface. In one of claims 1 to 6, wherein the control device, when the moving direction of the driving wheel has a convex-shaped step, while rotating the drive wheel, a direction in which the rear wheel presses the road The personal vehicle is characterized in that the rear wheel is assisted to lower the rear wheel support member toward the road surface, thereby assisting the rear wheel to get over the step. In one of the claims 1-9, the personal vehicle, wherein a detecting means for detecting a slip of said drive wheel is provided. The control device according to any one of claims 1 to 10 , wherein when the slip of the drive wheel is detected, the control device operates the rear wheel support member in a direction in which the rear wheel is raised. A personal vehicle characterized by performing control for improving the ground contact and releasing the slip of the driving wheel. In one of claims 1 to 1 1, wherein the control device, when it is detected that the driving wheel is shifted to the upper surface of the convex stepped actuates the rear wheel support member and the A personal vehicle characterized in that the vehicle is controlled to travel in the first mode by lowering the rear wheel to ground the rear wheel. 3. The control device according to claim 1 , wherein when the control device travels on the upper surface of the step in the first mode and then descends the upper surface of the step and shifts to the road surface, the driving wheel slips. Then, the personal vehicle is characterized in that the rear wheel is lifted by the rear wheel support member to perform control for improving the grounding property of the drive wheel.

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