JP5834835B2 - vehicle - Google Patents

Description

  The present invention relates to a vehicle having at least a pair of left and right wheels.

  In recent years, in view of the problem of depletion of energy resources, there has been a strong demand for fuel saving of vehicles. On the other hand, the number of vehicle owners is increasing due to the low price of vehicles, and one person tends to own one vehicle. Therefore, for example, there is a problem that energy is wasted when only one driver drives a four-seater vehicle. The most efficient way to save fuel consumption by reducing the size of the vehicle is to configure the vehicle as a one-seater tricycle or four-wheel vehicle.

  However, depending on the running state, the stability of the vehicle may decrease. Therefore, a technique for improving the stability of the vehicle during turning by tilting the vehicle body in the lateral direction has been proposed (for example, see Patent Document 1).

JP 2008-155671 A

  However, in the conventional vehicle, in order to improve the turning performance, the vehicle body can be tilted inward in the turning direction. However, the tread is affected by the centrifugal force acting outward in the turning direction. When the vehicle is narrow, when the position of the center of gravity is high, or when the steering speed is high, the stability of the vehicle is likely to decrease, and the passenger may feel uncomfortable or feel uneasy.

  The present invention solves the problems of the conventional vehicle, and the amount of change in the reduction ratio of the steering angle of the steered wheel that the steering actuator changes in response to the steering angle command input to the steering device tilts the vehicle body. By controlling so as not to exceed the limit value of the link angular acceleration of the link mechanism to be operated, the reduction ratio of the steering angle of the steered wheel with respect to the steering angle command greatly changes even when sudden deceleration is performed during turning. The stability of the vehicle body can be maintained, the turning performance can be improved, the occupant does not feel uncomfortable, the ride is comfortable, and the driving condition is stable. An object is to provide a highly safe vehicle that can be realized.

Therefore, in the vehicle of the present invention, a vehicle body including a steering unit and a main body unit that are connected to each other, a wheel that is rotatably attached to the steering unit, and a steerable steering wheel that steers the vehicle body, A non-steerable wheel that is rotatably attached to the main body, and is a steering device that inputs a steering angle command; a link mechanism that tilts the steering part or the main body in a turning direction; A tilting actuator device that operates the link mechanism, a steering actuator device that changes a steering angle of the steered wheel based on a steering angle command input from the steering device, the tilting actuator device, and the steering actuator device and a control unit for controlling a control device is changed by the reduction ratio of the steering angle of the steering wheel relative to the steering angle command changes Misao Adjust the target value of the angular, the controlling the steering actuator device as linked angular acceleration prediction value of the link mechanism does not exceed a limit value of the link angular acceleration.

  According to the configuration of the first aspect, even when sudden deceleration is performed during a turn, the reduction ratio of the steering angle of the steered wheel with respect to the steering angle command does not change greatly, and the actual steering angle Is set to an appropriate value, so that even when the tread is narrow or the center of gravity is high, the vehicle body can be tilted inward in the turning direction in a stable state and can be turned.

  According to the configurations of claims 2 and 3, since the reduction ratio of the steering angle of the steered wheel with respect to the steering angle command is set to an appropriate value, the stability of the vehicle body can be maintained and the turning performance can be improved. Can do.

  According to the configuration of claim 4, even when the vehicle speed is high, the stability of the vehicle body can be maintained, and the turning performance can be improved.

It is a right view which shows the structure of the vehicle in embodiment of this invention. It is a figure which shows the structure of the link mechanism of the vehicle in embodiment of this invention. It is a rear view which shows the structure of the vehicle in embodiment of this invention. It is a block diagram which shows the structure of the vehicle body tilt control system in embodiment of this invention. It is a block diagram of a control system in an embodiment of the present invention. It is a figure which shows the dynamic model explaining the inclination operation | movement of the vehicle body at the time of turning driving | running | working in embodiment of this invention. It is a flowchart which shows the operation | movement of the lateral acceleration calculation process in embodiment of this invention. It is a figure which shows the model explaining the vehicle body link angle | corner in embodiment of this invention. It is a flowchart which shows the operation | movement of the link angular velocity estimation process in embodiment of this invention. It is a flowchart which shows the subroutine of the differentiation process of the yaw rate in embodiment of this invention. It is a flowchart which shows the subroutine of the filter process in embodiment of this invention. It is a flowchart which shows the operation | movement of the inclination control process in embodiment of this invention. It is a flowchart which shows the operation | movement of the link motor control process in embodiment of this invention. It is a figure explaining lateral acceleration by steering in an embodiment of the invention. It is a figure which shows the relationship between the variable reduction ratio and vehicle speed in embodiment of this invention. It is a figure explaining the lateral acceleration which acts on the gravity center of the vehicle body in embodiment of this invention. It is a figure explaining the relationship between the lateral acceleration and gravity which act on the gravity center of the vehicle body in embodiment of this invention, gravity, and a link angle. It is a flowchart which shows the operation | movement of the steering control process in embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  1 is a right side view showing a configuration of a vehicle in an embodiment of the present invention, FIG. 2 is a diagram showing a configuration of a link mechanism of the vehicle in the embodiment of the present invention, and FIG. 3 is a vehicle in the embodiment of the present invention. It is a rear view which shows the structure. 3A is a diagram showing a state where the vehicle body is standing upright, and FIG. 3B is a diagram showing a state where the vehicle body is inclined.

  In the figure, reference numeral 10 denotes a vehicle according to the present embodiment, which includes a main body 20 as a vehicle body drive unit, a riding unit 11 as a steering unit on which an occupant gets on and steer, and a center in the width direction in front of the vehicle body. A wheel 12F as a steerable steering wheel which is a front wheel disposed on the left side, and a left wheel 12L and a right wheel 12R as non-steering wheels which are drive wheels disposed rearward as rear wheels and cannot be steered. And have. Furthermore, the vehicle 10 operates as a lean mechanism for leaning the vehicle body from side to side, that is, as a lean mechanism, that is, a vehicle body tilt mechanism, supporting the left and right wheels 12L and 12R, and the link mechanism 30. And a link motor 25 as a tilt actuator device. The vehicle 10 may be a three-wheeled vehicle with two front wheels on the left and right and one wheel on the rear, or may be a four-wheeled vehicle with two wheels on the left and right. As shown in the figure, a case will be described in which the front wheel is a single wheel and the rear wheel is a left and right tricycle. Further, although the steered wheel may function as a drive wheel, in the present embodiment, the description will be made assuming that the steered wheel does not function as a drive wheel.

  When turning, the angle of the left and right wheels 12L and 12R with respect to the road surface 18, that is, the camber angle is changed, and the vehicle body including the riding portion 11 and the main body portion 20 is inclined toward the turning inner wheel, thereby improving turning performance and the occupant. It is possible to ensure the comfort of the car. That is, the vehicle 10 can tilt the vehicle body in the lateral direction (left and right direction). In the example shown in FIGS. 2 and 3 (a), the left and right wheels 12L and 12R are upright with respect to the road surface 18, that is, the camber angle is 0 degree. In the example shown in FIG. 3B, the left and right wheels 12L and 12R are inclined in the right direction with respect to the road surface 18, that is, a camber angle is given.

  The link mechanism 30 includes a left vertical link unit 33L that supports a left wheel 12L and a left rotation driving device 51L including an electric motor that applies driving force to the wheel 12L, a right wheel 12R, and the wheel 12R. A right vertical link unit 33R that supports a right rotation drive device 51R composed of an electric motor or the like that applies a driving force to an upper side, and an upper horizontal link unit 31U that connects the upper ends of the left and right vertical link units 33L and 33R; The lower horizontal link unit 31D that connects the lower ends of the left and right vertical link units 33L and 33R, and the central vertical member 21 that has an upper end fixed to the main body 20 and extends vertically. The left and right vertical link units 33L and 33R and the upper and lower horizontal link units 31U and 31D are rotatably connected. Further, the upper and lower horizontal link units 31U and 31D are rotatably connected to the central vertical member 21 at the center thereof. When the left and right wheels 12L and 12R, the left and right rotational drive devices 51L and 51R, the left and right vertical link units 33L and 33R, and the upper and lower horizontal link units 31U and 31D are described in an integrated manner, The rotation drive device 51, the vertical link unit 33, and the horizontal link unit 31 will be described.

  The rotational drive device 51 as a drive motor is a so-called in-wheel motor, and a rotating shaft as a rotor is fixed to the vertical link unit 33 and a body as a stator is rotatably attached to the body. Is connected to the shaft of the wheel 12, and the wheel 12 is rotated by the rotation of the rotating shaft. The rotational drive device 51 may be a motor other than an in-wheel motor.

  The link motor 25 is a rotary electric actuator including an electric motor or the like, and includes a cylindrical body as a stator and a rotating shaft as a rotor rotatably attached to the body. The body is fixed to the main body portion 20 via the mounting flange 22, and the rotating shaft is fixed to the lateral link unit 31 </ b> U on the upper side of the link mechanism 30. The rotation axis of the link motor 25 functions as an inclination axis for inclining the main body 20 and is coaxial with the rotation axis of the connecting portion between the central vertical member 21 and the upper horizontal link unit 31U. When the link motor 25 is driven to rotate the rotation shaft with respect to the body, the upper horizontal link unit 31U rotates with respect to the main body 20 and the central vertical member 21 fixed to the main body 20, The link mechanism 30 operates, that is, bends and stretches. Thereby, the main-body part 20 can be inclined. Note that the rotation axis of the link motor 25 may be fixed to the main body 20 and the central vertical member 21, and the body may be fixed to the upper horizontal link unit 31U.

  The link motor 25 includes a link angle sensor 25 a that detects a change in the link angle of the link mechanism 30. The link angle sensor 25a is a rotation angle sensor that detects the rotation angle of the rotation shaft with respect to the body in the link motor 25, and includes, for example, a resolver, an encoder, and the like. As described above, when the link motor 25 is driven to rotate the rotation shaft with respect to the body, the upper horizontal link unit 31U rotates with respect to the main body 20 and the central vertical member 21 fixed to the main body 20. Therefore, a change in the angle of the upper horizontal link unit 31U relative to the central vertical member 21, that is, a change in the link angle can be detected by detecting the rotation angle of the rotation shaft with respect to the body.

  The link motor 25 includes a lock mechanism (not shown) that fixes the rotation shaft to the body so as not to rotate. The lock mechanism is a mechanical mechanism, and preferably does not consume electric power while the rotation shaft is fixed to the body so as not to rotate. The lock mechanism can fix the rotation shaft so as not to rotate at a predetermined angle with respect to the body.

  The riding part 11 is connected to the front end of the main body part 20 via a connecting part (not shown). The connecting part may have a function of connecting the riding part 11 and the main body part 20 so as to be relatively displaceable in a predetermined direction.

  The boarding part 11 includes a seat 11a, a footrest 11b, and a windbreak part 11c. The seat 11 a is a part for a passenger to sit while the vehicle 10 is traveling. The footrest 11b is a part for supporting the occupant's foot, and is disposed on the front side (right side in FIG. 1) and below the seat 11a.

  Further, a battery device (not shown) is disposed behind or below the riding section 11 or on the main body section 20. The battery device is an energy supply source for the rotation drive device 51 and the link motor 25. In addition, a control device, an inverter device, various sensors, and the like (not shown) are accommodated in the rear portion or the lower portion of the riding portion 11 or the main body portion 20.

  A steering device 41 is disposed in front of the seat 11a. The steering device 41 is operated by an occupant to input steering command information such as a steering direction and a steering angle. A steering bar 41a as a steering device, a meter such as a speed meter, an indicator, a switch, and an acceleration command for inputting an acceleration command. Members required for steering such as a throttle lever as an input means and a brake lever as a deceleration command input means for inputting a deceleration command are provided. The occupant operates the handle bar 41a and other members to instruct the traveling state of the vehicle 10 (for example, traveling direction, traveling speed, turning direction, turning radius, etc.). As the steering device, other devices such as a steering wheel, a jog dial, a touch panel, and a push button can be used instead of the handle bar 41a.

  The wheel 12F is connected to the riding section 11 via a front wheel fork 17 that is a part of a suspension device (suspension device). The suspension device is a device similar to a suspension device for front wheels used in, for example, general motorcycles, bicycles, and the like, and the front wheel fork 17 is, for example, a telescopic type fork with a built-in spring. Then, as in the case of a general motorcycle, bicycle, etc., the wheel 12F as the steering wheel changes the steering angle in accordance with the operation of the handlebar 41a by the occupant, thereby changing the traveling direction of the vehicle 10.

  Specifically, the handle bar 41a is connected to the upper end of a steering shaft member (not shown), and the upper end of the steering shaft member is rotatably attached to a frame member (not shown) provided in the riding section 11. The steering shaft member is attached to the frame member in an obliquely inclined state so that the upper end is located behind the lower end. Then, the rotation angle with respect to the frame member at the upper end of the steering shaft member, that is, the steering wheel angle as the steering angle command inputted by the occupant operating the steering bar 41a is detected by the steering wheel angle sensor 62 as the input steering angle detection means. Is done. The handle angle sensor 62 includes, for example, an encoder.

A steering motor 65 as a steering actuator device is disposed between the upper end and the lower end of the steering shaft member, and the steering motor 65 has a handle angle detected by the handle angle sensor 62. Based on this, the lower end of the steering shaft member is rotated. The lower end of the steering shaft member is rotatably attached to the frame member and is connected to the upper end of the front wheel fork 17. The rotation angle of the lower end of the steering shaft member relative to the frame member, that is, the steering angle output from the steering motor 65 and transmitted to the wheel 12F via the front wheel fork 17 is the steering angle as output steering angle detection means. It is detected by the sensor 63. The steering angle sensor 63 is, for example, a rotation angle sensor that detects the rotation angle of the rotation shaft with respect to the body in the steering motor 65, and includes a resolver, an encoder, and the like. The distance between the left and right wheels 12L and 12R axle is the axle and the rear wheel of the wheel 12F is a front wheel, i.e., the wheel base is L _H.

  Further, a vehicle speed sensor 54 as a vehicle speed detecting means for detecting the vehicle speed as the traveling speed of the vehicle 10 is disposed at the lower end of the front wheel fork 17 that supports the axle of the wheel 12F or the axles of the wheels 12L and 12R. The vehicle speed sensor 54 is a sensor that detects the vehicle speed based on the rotational speed of the wheels 12F, 12L, or 12R, and includes, for example, an encoder.

  In the present embodiment, the vehicle 10 has a lateral acceleration sensor 44. The lateral acceleration sensor 44 is a sensor composed of a general acceleration sensor, a gyro sensor, or the like, and detects the lateral acceleration of the vehicle 10, that is, the acceleration in the lateral direction (horizontal direction in FIG. 3) as the width direction of the vehicle body. To do.

  Since the vehicle 10 is stabilized by inclining the vehicle body toward the inside of the turn at the time of turning, the vehicle 10 is controlled so that the centrifugal force to the outside of the turn at the time of turning and the gravity are balanced by turning the vehicle body. By performing such control, for example, even if the road surface 18 is inclined in a direction perpendicular to the traveling direction (left and right direction with respect to the traveling direction), the vehicle body can always be kept horizontal. As a result, the vehicle body and the occupant are apparently always subjected to gravity downward in the vertical direction, the sense of incongruity is reduced, and the stability of the vehicle 10 is improved.

  Therefore, in the present embodiment, in order to detect the lateral acceleration of the leaning vehicle body, the lateral acceleration sensor 44 is attached to the vehicle body, and feedback control is performed so that the output of the lateral acceleration sensor 44 becomes zero. As a result, the vehicle body can be tilted to an inclination angle at which the centrifugal force acting during turning and gravity are balanced. Further, even when the road surface 18 is inclined in a direction perpendicular to the traveling direction, the vehicle body can be controlled to have an inclination angle that makes the vehicle body vertical. The lateral acceleration sensor 44 is disposed so as to be positioned at the center in the width direction of the vehicle body, that is, on the longitudinal axis of the vehicle body.

  However, if there is one lateral acceleration sensor 44, an unnecessary acceleration component may be detected. For example, while the vehicle 10 is traveling, only one of the left and right wheels 12L and 12R may fall into the depression on the road surface 18. In this case, since the vehicle body is tilted, the lateral acceleration sensor 44 is displaced in the circumferential direction and detects the acceleration in the circumferential direction. That is, an acceleration component that is not directly derived from centrifugal force or gravity, that is, an unnecessary acceleration component is detected.

  In addition, the vehicle 10 includes a portion that functions as a spring and has elasticity like the tire portions of the left and right wheels 12 </ b> L and 12 </ b> R. For this reason, the lateral acceleration sensor 44 is considered to be attached to the vehicle body through inevitable play and springs, and therefore acceleration generated by the displacement of the play and springs is also detected as an unnecessary acceleration component.

  Such an unnecessary acceleration component may deteriorate the controllability of the vehicle body tilt control system. For example, if the control gain of the vehicle body tilt control system is increased, control system vibration, divergence, and the like due to unnecessary acceleration components occur, so that it is not possible to increase the control gain even if responsiveness is to be improved. .

  Therefore, in the present embodiment, a plurality of lateral acceleration sensors 44 are provided at different heights. In the example shown in FIGS. 1 and 3, there are two lateral acceleration sensors 44, a first lateral acceleration sensor 44a and a second lateral acceleration sensor 44b, which are a first lateral acceleration sensor 44a and a second lateral acceleration sensor 44b. Are arranged at different height positions. By appropriately selecting the positions of the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b, unnecessary acceleration components can be effectively removed.

Specifically, as shown in FIG. 3 (a), the first lateral acceleration sensor 44a is in the back of the riding section 11, the distance from the road surface 18, i.e., is disposed at the position of L ₁ Height ing. The second lateral acceleration sensor 44b is the upper surface of the rear or body portion 20 of the riding portion 11, the distance from the road surface 18, i.e., is disposed at a position of L ₂ height. Note that L ₁ > L ₂ . When turning, when the vehicle is turned with the vehicle body tilted inward (right side in the drawing) as shown in FIG. 3B, the first lateral acceleration sensor 44a detects the lateral acceleration. The detection value a ₁ is output, and the second lateral acceleration sensor 44b detects the lateral acceleration and outputs the detection value a ₂ . Although the center of the tilting motion when the vehicle body tilts, that is, the roll center, is strictly located slightly below the road surface 18, it is considered that the center is substantially equal to the road surface 18 in practice.

It is desirable that both the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b are attached to a sufficiently rigid member. Further, if the difference between L ₁ and L ₂ is small, the difference between the detection values a ₁ and a ₂ is small. Therefore, it is desirable that the difference be sufficiently large, for example, 0.3 [m] or more. Furthermore, it is desirable that both the first lateral acceleration sensor 44 a and the second lateral acceleration sensor 44 b are disposed above the link mechanism 30. Further, when the vehicle body is supported by a spring such as a suspension, it is desirable that both the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b are arranged on a so-called “spring top”. Further, both the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b may be disposed between the axle of the front wheel 12F and the axles of the left and right wheels 12L and 12R as rear wheels. desirable. Furthermore, it is desirable that both the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b are disposed as close to the occupant as possible. Further, both the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b are preferably located on the central axis of the vehicle body extending in the traveling direction when viewed from above, that is, not offset with respect to the traveling direction. .

  In the present embodiment, a roll rate sensor 44c for detecting the angular velocity of the tilting motion of the vehicle body and a yaw rate sensor 44d as a yaw angular velocity detecting means for detecting the angular velocity of the turning motion of the vehicle body, that is, the yaw angular velocity of the vehicle body are arranged. It is installed. Specifically, it is desirable that both the roll rate sensor 44c and the yaw rate sensor 44d are located on the central axis of the vehicle body extending in the traveling direction when viewed from above, that is, not offset with respect to the traveling direction. It is arranged between the seat 11a and the footrest 11b.

  The roll rate sensor 44c is a general roll rate sensor, and for example, a gyro sensor is attached so as to detect a rotational angular velocity in a plane perpendicular to the road surface 18. . The yaw rate sensor 44d is a general yaw rate sensor, and for example, a gyro sensor is attached so as to detect a rotational angular velocity in a plane parallel to the road surface 18. Note that the three-dimensional gyro sensor can exhibit the functions of the roll rate sensor 44c and the yaw rate sensor 44d. That is, the roll rate sensor 44c and the yaw rate sensor 44d may be configured separately or may be configured integrally.

  The vehicle 10 in the present embodiment has a vehicle body tilt control system as a part of the control device. The vehicle body tilt control system is a kind of computer system, and includes a tilt control device, a steering control device, and a drive control device including an ECU (Electronic Control Unit) or the like. The tilt control device includes arithmetic means such as a processor, storage means such as a magnetic disk and a semiconductor memory, an input / output interface, and the like, and includes a link angle sensor 25a, a first lateral acceleration sensor 44a, a second lateral acceleration sensor 44b, a roll rate. The sensor 44c, the yaw rate sensor 44d, the vehicle speed sensor 54, and the link motor 25 are connected. Then, the tilt control device outputs a torque command value for operating the link motor 25. Further, the steering control device includes a calculation means such as a processor, a storage means such as a magnetic disk and a semiconductor memory, an input / output interface, and the like, and is connected to a handle angle sensor 62, a steering angle sensor 63, a vehicle speed sensor 54, and a steering motor 65. Has been. Further, the drive control device includes a calculation unit such as a processor, a storage unit such as a magnetic disk and a semiconductor memory, an input / output interface, and the like, and is connected to a brake sensor 58, a throttle sensor 59, and a rotary drive unit 51 described later. Yes. The steering control device outputs a control pulse for operating the steering motor 65. In addition, the tilt control device, the steering control device, and the drive control device are not necessarily configured separately, and may be configured integrally.

  The tilt control device performs feedback control and feedforward control during turning, so that the tilt angle of the vehicle body is such that the lateral acceleration value detected by the lateral acceleration sensor 44 becomes an angle that becomes zero. The motor 25 is operated. That is, the tilt angle of the vehicle body is controlled so that the centrifugal force to the outside of the turn balances with the gravity and the lateral acceleration component becomes zero. As a result, a force in a direction parallel to the longitudinal axis of the vehicle body acts on the vehicle body and the occupant on the riding section 11. Therefore, the stability of the vehicle body can be maintained and the turning performance can be improved.

  Also, when a disturbance in the tilt direction is received, a part due to the disturbance in the change in the tilt angle of the vehicle body is extracted, and for the remaining part, the tilt angle of the vehicle body is controlled in the normal mode, and the extracted part In contrast, the vehicle body tilt angle is controlled in the disturbance response mode. Therefore, the stability of the vehicle body can be maintained even when subjected to disturbance. In addition, the rider does not feel discomfort and the ride comfort is improved.

  Further, in the present embodiment, the steering angle command input by the occupant operating the handle bar 41a is reduced according to the vehicle speed and the leaning state of the vehicle body to control the steering angle of the wheel 12F. More specifically, a variable reduction ratio as a steering reduction ratio is set based on the vehicle speed and the link angle of the link mechanism 30 for tilting the vehicle body, and a steering motor as a steering actuator device is set according to the variable reduction ratio. The steering angle target value of the wheel 12F as the steering wheel 65 to be changed is reduced with respect to the steering angle sensor value as the input steering angle command.

  The variable reduction ratio is controlled according to the vehicle speed so that the link angle does not exceed a preset link angle limit value. Further, the variable reduction ratio is determined so as to increase as the vehicle speed increases.

  Further, the steering angle of the wheel 12F is controlled so that the amount of change in the variable reduction ratio does not exceed the limit value of the link angular acceleration of the link mechanism 30.

  As a result, even when sudden deceleration is performed during a turn, the change in the variable reduction ratio does not become excessively large, so that the stability of the vehicle 10 does not deteriorate.

  If the vehicle body tilt control is performed without performing such steering control, for example, if the sudden deceleration is performed during a turn, the variable reduction ratio changes greatly, and as a result, the vehicle speed is rapidly reduced. The steering angle target value of the wheel 12F is set to be unnecessarily large, and the stability of the vehicle 10 may be lowered.

  On the other hand, in the present embodiment, since the amount of change in the variable reduction ratio does not exceed the limit value of the link angular acceleration of the link mechanism 30, the steering angle of the wheel 12F is set to an appropriate value. It is set, and the vehicle body can be tilted inward in the turning direction in a stable state to perform turning.

  Next, the configuration of the vehicle body tilt control system will be described.

  FIG. 4 is a block diagram showing the configuration of the vehicle body tilt control system in the embodiment of the present invention.

  In the figure, 46 is an inclination control ECU as an inclination control device, and includes a link angle sensor 25a, a first lateral acceleration sensor 44a, a second lateral acceleration sensor 44b, a roll rate sensor 44c, a yaw rate sensor 44d, a vehicle speed sensor 54, and a link motor. 25. The tilt control ECU 46 includes a lateral acceleration calculation unit 48, a link angular velocity estimation unit 50, a disturbance calculation unit 43, a tilt control unit 47, and a link motor control unit 42.

  Reference numeral 61 denotes a steering control ECU as a steering control device, which is connected to a handle angle sensor 62, a steering angle sensor 63, a vehicle speed sensor 54, and a steering motor 65. The steering control ECU 61 includes a steering control unit 66 and a steering motor control unit 67.

  Reference numeral 55 denotes a drive control ECU as a drive control device, which is connected to a brake sensor 58, a throttle sensor 59, and a rotary drive device 51 as a drive motor. The drive control ECU 55 includes a drive control unit 56 and a drive motor control unit 57.

  Here, the lateral acceleration calculation unit 48 calculates a combined lateral acceleration based on the lateral acceleration detected by the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b. The link angular velocity estimation unit 50 calculates a link angular velocity prediction value based on the yaw rate as the yaw angular velocity detected by the yaw rate sensor 44d and the vehicle speed detected by the vehicle speed sensor 54. Further, the disturbance calculation unit 43 calculates a roll rate for the disturbance based on the roll rate as the angular velocity of the tilting motion of the vehicle body detected by the roll rate sensor 44c and the link angle detected by the link angle sensor 25a.

  The tilt controller 47 is based on the combined lateral acceleration calculated by the lateral acceleration calculator 48, the predicted link angular velocity calculated by the link angular velocity estimator 50, and the disturbance roll rate calculated by the disturbance calculator 43. Then, the speed command value as the control value is calculated and output. Further, the link motor control unit 42 outputs a torque command value as a control value for operating the link motor 25 based on the speed command value output from the inclination control unit 47.

  Further, the steering control unit 66 controls the steering wheel steering angle as a control value based on the steering wheel angle detected by the steering wheel angle sensor 62, the steering angle detected by the steering angle sensor 63, and the vehicle speed detected by the vehicle speed sensor 54. Calculates and outputs the command value. The steering motor control unit 67 is a control pulse as a control value for operating the steering motor 65 based on the steering angle detected by the steering angle sensor 63 and the steering wheel steering angle command value output by the steering control unit 66. Is output.

  Further, the drive control unit 56 controls the control value based on the deceleration command value as the brake lever operation amount detected by the brake sensor 58 and the acceleration command value as the throttle lever operation amount detected by the throttle sensor 59. The drive command value is calculated and output. The drive motor control unit 57 outputs a torque command value as a control value for operating the rotary drive device 51 based on the drive command value output by the drive control unit 56.

  Next, the operation of the vehicle 10 configured as described above will be described. First, the operation of the lateral acceleration calculation process, which is a part of the operation of the vehicle body tilt control process in turning, will be described.

  FIG. 5 is a block diagram of the control system in the embodiment of the present invention, FIG. 6 is a diagram showing a dynamic model for explaining the leaning operation of the vehicle body during turning traveling in the embodiment of the present invention, and FIG. 7 is an embodiment of the present invention. It is a flowchart which shows the operation | movement of the lateral acceleration calculation process in the form.

  In the vehicle body tilt control process according to the present embodiment, control in which tilt control by the tilt control ECU 46 and steering control by the steering control ECU 61 are combined as shown in FIG. 5 is performed. Note that the tilt control by the tilt control ECU 46 is a combination of feedback control and feedforward control.

In FIG. 5, f ₁ is a transfer function represented by Equation (6) described later, G _P , G _RP, and G _YD are control gains of the proportional control operation, LPF is a low-pass filter, and s is It is a differential element. Further, f ₂ is a link angular velocity prediction value expressed by the following formula (10), and f ₃ is a roll rate gain.

  When turning is started, the vehicle body tilt control system starts the vehicle body tilt control process. By performing posture control, the vehicle 10 turns with the link mechanism 30 in a state where the vehicle body is tilted inward (right side in the drawing) as shown in FIG. Further, during turning, a centrifugal force to the outside of the turning acts on the vehicle body, and a lateral component of gravity is generated by tilting the vehicle body to the inside of the turn. Then, the lateral acceleration calculation unit 48 executes a lateral acceleration calculation process, calculates a combined lateral acceleration a, and outputs it to the tilt control unit 47. Then, the inclination control unit 47 performs feedback control, and outputs a speed command value as a control value such that the value of the combined lateral acceleration a becomes zero. Then, the link motor control unit 42 outputs a torque command value to the link motor 25 based on the speed command value output from the inclination control unit 47.

The vehicle body tilt control process is a process that is repeatedly executed by the vehicle body tilt control system at a predetermined control cycle T _S (for example, 5 [ms]) while the vehicle 10 is turned on. This is a process for improving turning performance and ensuring passenger comfort.

  In FIG. 6, 44A is a first sensor position indicating the position where the first lateral acceleration sensor 44a is disposed on the vehicle body, and 44B is a first position indicating the position where the second lateral acceleration sensor 44b is disposed on the vehicle body. Two sensor positions.

The acceleration detected by the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b and outputting the detected value is <1> centrifugal force acting on the vehicle body when turning, and <2> tilting the vehicle body toward the inside of the turn. The lateral component of the generated gravity, <3> the first lateral acceleration sensor 44a and the like due to the inclination of the vehicle body, the backlash or the displacement of the spring, etc., when only one of the left and right wheels 12L and 12R falls into the depression of the road surface 18; The acceleration generated by the displacement of the second lateral acceleration sensor 44b in the circumferential direction, and the <4> operation of the link motor 25 or the reaction thereof causes the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b to be displaced in the circumferential direction. It is considered that there are four accelerations caused by this. Of these four acceleration, the <1> and <2>, the height of the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b, that is, independent of L ₁ and L _2. On the other hand, since <3> and <4> are accelerations generated by displacement in the circumferential direction, they are proportional to the distance from the roll center, that is, roughly proportional to L ₁ and L ₂ .

Here, the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44a and the second lateral acceleration sensor 44b detect and output the detected value. The acceleration <3> is defined as a _X1 and a _X2, and the first lateral acceleration sensor 44a and the second lateral acceleration. The acceleration of <4>, which is detected by the sensor 44b and outputs the detected value, is a _M1 and a _M2 . Further, the acceleration of <1> to the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b outputs the detected value detected by the a _T, a first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b is detected Then, the acceleration of <2> that outputs the detected value is defined as a _G. Since <1> and <2> are irrelevant to the heights of the first and second lateral acceleration sensors 44a and 44b, the detection values of the first and second lateral acceleration sensors 44a and 44b are equal. .

Then, only one of the left and right wheels 12L and 12R are inclined in the vehicle body due to the fall in a recess of a road surface 18, the angular velocity omega _R the circumferential direction of displacement by the displacement or the like of Gataya spring, the angular acceleration omega _{Let R} '. Further, the angular velocity of the circumferential displacement due to the operation of the link motor 25 or its reaction is ω _M , and the angular acceleration is ω _M ′. The angular velocity ω _M or the angular acceleration ω _M ′ can be obtained from the detection value of the link angle sensor 25a.

Then, a _X1 = L ₁ ω _R ′, a _X2 = L ₂ ω _R ′, a _M1 = L ₁ ω _M ′, a _M2 = L ₂ ω _M ′.

Further, when the detection value of the acceleration by the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b is detecting and outputting the a ₁ and a _2, a ₁ and a _2, four acceleration <1> to <4 It is represented by the following formulas (1) and (2).
_{a 1 = a T + a G} + L 1 ω R '+ L 1 ω M' ··· formula (1)
_{a 2 = a T + a G} + L 2 ω R '+ L 2 ω M' ··· formula (2)
Then, by subtracting equation (2) from equation (1), the following equation (3) can be obtained.
a ₁ −a ₂ = (L ₁ −L ₂ ) ω _R ′ + (L ₁ −L ₂ ) ω _M ′ Equation (3)
Here, the values of L ₁ and L ₂ are known because they are the heights of the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b. The value of ω _M ′ is known because it is a differential value of the angular velocity ω _M of the link motor 25. Then, on the right side of the equation (3), only the value of ω _R ′ of the first term is unknown, and all other values are known. Therefore, the value of ω _R ′ can be obtained from the detection values a ₁ and a _{2 of} the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b. That is, unnecessary acceleration components can be removed based on the detection values a ₁ and a ₂ of the first lateral acceleration sensor 44a and the second lateral acceleration sensor 44b.

When the vehicle body tilt control system starts the vehicle body tilt control process, the lateral acceleration calculation unit 48 starts the lateral acceleration calculation process, and first acquires the first lateral acceleration sensor value a ₁ (step S1) and the second lateral acceleration calculation process. An acceleration sensor value a ₂ is acquired (step S2). Then, the lateral acceleration calculation unit 48 calculates the acceleration difference Δa (step S3). The Δa is expressed by the following equation (4).
Δa = a ₁ −a ₂ Formula (4)
Then, the lateral acceleration calculation unit 48 performs ΔL call (step S4), and performs the L ₂ call (step S5). The ΔL is expressed by the following equation (5).
ΔL = L ₁ −L ₂ Formula (5)
Subsequently, the lateral acceleration calculation unit 48 calculates a combined lateral acceleration a (step S6). Incidentally, the synthetic lateral acceleration a lateral acceleration sensor 44 is a value corresponding to the lateral acceleration sensor value a when the one, first lateral acceleration sensor value a ₁ and the second lateral acceleration sensor value a ₂ Is obtained by the following equations (6) and (7).
a = a ₂ − (L ₂ / ΔL) Δa (6)
a = a ₁ − (L ₁ / ΔL) Δa (7)
Theoretically, the same value can be obtained by both equation (6) and equation (7), but since the acceleration caused by the circumferential displacement is proportional to the distance from the roll center, in practice, the roll center It is desirable to use a ₂ which is a detection value of the lateral acceleration sensor 44 closer to the second lateral acceleration sensor 44b as a reference. Therefore, in the present embodiment, the combined lateral acceleration a is calculated by Expression (6).

  Finally, the lateral acceleration calculation unit 48 sends the combined lateral acceleration a to the tilt control unit 47 (step S7), and ends the lateral acceleration calculation process.

Thus, in this embodiment, a first lateral acceleration sensor 44a and a second lateral acceleration sensor 44b is placed in different height positions, a first lateral acceleration sensor value a ₁ and the second lateral acceleration sensor A combined lateral acceleration a obtained by combining the value a ₂ is calculated, and feedback control is performed so that the value of the combined lateral acceleration a becomes zero to control the tilt angle of the vehicle body.

  As a result, unnecessary acceleration components can be removed, so that it is not affected by road surface conditions, the occurrence of vibrations and divergence of the control system can be prevented, and the control gain of the vehicle body tilt control system is increased. Control responsiveness can be improved.

  In the present embodiment, the case where there are two lateral acceleration sensors 44 has been described. However, if there are a plurality of lateral acceleration sensors 44 arranged at different heights, the number of lateral acceleration sensors 44 is three or more. There may be any number.

  Next, the operation of the link angular velocity estimation process for estimating the link angular velocity in turning travel will be described.

  FIG. 8 is a diagram showing a model for explaining the vehicle body link angle in the embodiment of the present invention, FIG. 9 is a flowchart showing the operation of link angular velocity estimation processing in the embodiment of the present invention, and FIG. 10 is an embodiment of the present invention. FIG. 11 is a flowchart showing a subroutine of the filter process in the embodiment of the present invention.

  When the link angular velocity estimation unit 50 starts the link angular velocity estimation process, the link angular velocity estimation unit 50 first acquires a yaw rate sensor value ψ that is a yaw rate value detected by the yaw rate sensor 44d (step S11), and a vehicle speed value detected by the vehicle speed sensor 54. The vehicle speed sensor value ν is obtained (step S12).

  Then, the link angular velocity estimation unit 50 performs yaw rate differentiation processing (step S13) and calculates Δψ. The Δψ is a value obtained by differentiating the yaw rate with time, and corresponds to the yaw angular acceleration.

In the yaw rate differentiation process, the link angular velocity estimation unit 50 first makes a ψ _old call (step S13-1). Note that ψ _old is the value of ψ (t) saved when the previous vehicle body tilt control process was executed. In the initial setting, ψ _old = 0.

Subsequently, the link angular velocity estimation unit 50 acquires a control cycle T _S (step S13-2).

Subsequently, the link angular velocity estimation unit 50 calculates the yaw rate differential value Δψ (step S13-3). Δψ is calculated by the following equation (8).
Δψ = (ψ (t) −ψ _old ) / T _S (8)
The link angular velocity estimation unit 50 stores ψ _old = ψ (t) (step S13-4), and ends the yaw rate differentiation process.

  Subsequently, the link angular velocity estimation unit 50 performs a filtering process on the yaw rate differential value Δψ (step S14).

In the filter processing, the link angular velocity estimation unit 50 first acquires a control cycle T _S (step S14-1).

  Subsequently, the link angular velocity estimation unit 50 acquires a cutoff frequency w (step S14-2).

Subsequently, the link angular velocity estimation unit 50 performs a Δψ _old call (step S14-3). Note that Δψ _old is a value of Δψ (t) saved when the previous vehicle body tilt control process was executed.

Subsequently, the link angular velocity estimation unit 50 calculates the filtered yaw rate differential value Δψ (t) (step S14-4). Δψ (t) is calculated by the following equation (9).
_{Δψ (t) = Δψ old /} (1 + T S w) + T S wψ / (1 + T S w) ··· (9)
The expression (9) is an expression of an IIR (Infinite Impulse Response) filter generally used as a bandpass filter, but a first-order lag low-pass filter may be simply used. As the IIR filter, for example, a Chebyshev type II filter may be used, or another filter may be used. Further, a generally used FIR (Finite Impulse Response) filter may be used. Furthermore, the cut-off frequency (−3 [dB] frequency) of the band pass filter is preferably 10 [Hz] or less, and more preferably several [Hz].

Then, the link angular velocity estimation unit 50 stores it as Δψ _old = Δψ (t) (step S14-5), and ends the filter process. That is, the value of Δψ (t) calculated at the time of execution of the current vehicle body tilt control process is stored in the storage unit as Δψ _old .

Subsequently, the link angular velocity estimation unit 50 calculates a link angular velocity prediction value f ₂ (step S15). Here, assuming that gravity is g, the link angular velocity predicted value f ₂ is calculated by the following equation (10).
f ₂ = dη / dt = Δη = (ν / g) (dψ / dt) (10)
As described above, the link angle sensor 25a detects a change in the angle of the upper horizontal link unit 31U with respect to the central vertical member 21, that is, a change in the link angle. Here, it is assumed that the link angle sensor value, that is, the link angle is η, and the inclination angle of the vehicle body at the time of turning is controlled so that the centrifugal force a ₀ as the lateral acceleration and the gravity g are balanced. If 18 is horizontal, the centrifugal force a ₀ and the gravity g are as shown in FIG. 8, and the relationship represented by the following formula (11) is present between the centrifugal force a ₀ and the gravity g. To establish.
a ₀ cos η = gsin η (11)
From the equation (11), the following equation (12) is derived.
a ₀ / g = sin η / cos η = tan η (12)
Further, the following equation (13) is derived from the equation (12).
a ₀ = g tan η (13)
On the other hand, assuming that the yaw rate sensor value, that is, the yaw rate is ψ, and the turning radius is r, the vehicle speed sensor value, that is, the vehicle speed ν and the centrifugal force a ₀ as the lateral acceleration acting on the vehicle body at the time of turning are It is represented by (14) and (15).
ν = rψ Equation (14)
a ₀ = rψ ² = νψ (15)
Then, the following equation (16) is derived from the equation (15) and the equation (13).
tan η = νψ / g (16)
Furthermore, it can be approximated as tan η≈η, and the change in the vehicle speed ν is sufficiently slow compared to the change in the link angle η, so that the vehicle speed ν can be regarded as a constant. From the above, the formula (10) can be obtained.

Subsequently, the link angular velocity estimation unit 50 calculates a link angular velocity control value a _f (step S16). The link angular velocity control value _af is calculated by the following equation (17).
a _f = Adη / dt (17)
Here, A is an arbitrary value of 0 to 1, and is a tuning constant determined according to the structure of the vehicle 10.

Finally, the link angular velocity estimation unit 50 sends the link angular velocity control value a _f to the inclination control unit 47 (step S17), and ends the link angular velocity estimation process.

  Next, the operation of the inclination control process for outputting the speed command value to the link motor control unit 42 will be described.

  FIG. 12 is a flowchart showing the operation of the tilt control process in the embodiment of the present invention.

  In the tilt control process, the tilt control unit 47 first receives the combined lateral acceleration a from the lateral acceleration calculation unit 48 (step S21).

Subsequently, the inclination control unit 47 makes an _old call (step S22). a _old is the combined lateral acceleration a stored when the vehicle body tilt control process is executed last time. In the initial setting, a _old = 0.

Subsequently, the inclination control unit 47 acquires the control cycle T _S (step S23), and calculates the differential value of a (step S24). Here, when the differential value of a is da / dt, the da / dt is calculated by the following equation (18).
da / dt = (a−a _old ) / T _S (18)
And the inclination control part 47 is preserve | saved as _aold = a (step S25). That is, the lateral acceleration sensor value a acquired at the time of execution of the current vehicle body tilt control process is stored as a _old in the storage unit.

Then, tilt control unit 47 calculates the first control value U _P (step S26). Here, if the control gain of the proportional control operation, that is, the proportional gain is _GP , the first control value _UP is calculated by the following equation (19).
U _P = G _P a ··· (19)
Then, tilt control unit 47 calculates the second control value U _D (step S27). Here, if the control gain of the differential control operation, that is, the differential time is G _D , the second control value U _D is calculated by the following equation (20).
U _D = G _D da / dt (20)
Subsequently, the inclination control unit 47 calculates a third control value U (step S28). Third control value U is the sum of the first control value U _P and the second control value U _D, is calculated by the following equation (21).
U = U _P + U _D ··· formula (21)
When the third control value U is calculated, the inclination control unit 47 receives the link angular velocity control value a _f from the link angular velocity estimation unit 50 (step S29).

Subsequently, the inclination control unit 47 calculates a fourth control value U (step S30). The fourth control value U is the sum of the third control value U and the link angular velocity control value _af, and is calculated by the following equation (22).
U = U + a _f Expression (22)
Finally, the tilt control unit 47 outputs the fourth control value U as a speed command value to the link motor control unit 42 (step S31), and ends the tilt control process.

  Next, the operation of the link motor control process for outputting a torque command value to the link motor 25 will be described.

  FIG. 13 is a flowchart showing the operation of the link motor control process in the embodiment of the present invention.

  In the link motor control process, the link motor control unit 42 first receives the fourth control value U from the inclination control unit 47 (step S41).

Subsequently, the link motor control unit 42 calculates a link motor control value as a torque command value for operating the link motor 25 (step S42). Here, when the link motor control value is U _M , the U _M is calculated by the following equation (23).
U _M = G _MP U (23)
Note that _GMP is a motor control proportional gain, and the value of _{GMP is} a value set based on experiments or the like, and is stored in the storage means in advance.

Finally, the link motor control unit 42 outputs the link motor control value _UM to the link motor 25 (step S43), and ends the link motor control process.

  Although the link motor control process has been described here as proportional control, that is, P control, it may be PID control.

  Next, the operation of the steering control process, which is a part of the vehicle body control operation in turning, will be described.

  FIG. 14 is a diagram for explaining lateral acceleration due to steering in the embodiment of the present invention, FIG. 15 is a diagram showing the relationship between the variable reduction ratio and the vehicle speed in the embodiment of the present invention, and FIG. 16 is an embodiment of the present invention. FIG. 17 is a diagram for explaining the lateral acceleration acting on the center of gravity of the vehicle body in FIG. 17, FIG. 17 is a diagram for explaining the relationship between the lateral acceleration acting on the center of gravity of the vehicle body and the gravity and the link angle in the embodiment of the present invention, and FIG. It is a flowchart which shows the operation | movement of the steering control process in embodiment of this. In FIG. 16, (a) is a top view and (b) is a right side view.

When the steering control process in the present embodiment starts the steering control process, first, the steering angle sensor value δ _st that is the value of the steering wheel angle detected by the steering wheel angle sensor 62 is acquired (step S51). The steering wheel angle is a steering angle command input by an occupant operating the steering bar 41a.

Subsequently, the steering control unit 66 performs a filter process on the steering wheel angle sensor value δ _st (step S52). The filter process is a process using a low-pass filter similar to the filter process in the link angular velocity estimation process, and an IIR filter or FIR filter generally used as a band-pass filter can be used. A simple low-pass filter of the system may be used.

  Subsequently, the steering control unit 66 acquires a vehicle speed sensor value ν that is a value of the vehicle speed detected by the vehicle speed sensor 54 (step S53).

Subsequently, the steering control unit 66 acquires the steering wheel angle limit value δ _stlim (step S54). The steering wheel angle limit value δ _stlim is the maximum steering angle command value that can be input by the occupant operating the handle bar 41a, that is, a value indicating the maximum turning angle of the handle bar 41a. Is a physical limit value set in advance based on

Subsequently, the steering control unit 66 acquires the link angle limit value η _lim (step S55). The link angle limit value η _lim is the maximum value of the link angle that can be taken by the link mechanism 30 that tilts the vehicle body, and is a physical limit value set in advance based on the structure of the link mechanism 30 or the vehicle body. The limit value is set in advance so as to correspond to the upper limit value of the tilt angle that can maintain the stability of the vehicle body even when the vehicle is tilted.

Then, the steering control unit 66 obtains the wheel base L _H (step S56).

Subsequently, the steering control unit 66 calculates a variable reduction ratio γ as a reduction ratio of the steering angle (step S57). The variable reduction ratio γ is a ratio of a steering wheel angle, that is, a steering wheel sensor value δ _st and a steering steering angle target value δ ^*. The actual steering angle of the wheel 12F as a steering wheel is determined by the occupant. Is a coefficient that is set to maintain the stability of the vehicle body during turning even when the vehicle speed is increased by reducing the steering angle as a steering angle command input by operating. In the present embodiment, the variable reduction ratio γ is calculated as follows.

As shown in FIG. 14, if the steering angle is δ and the turning radius is r, the vehicle speed ν and the centrifugal force a ₀ as the lateral acceleration acting on the vehicle body at the time of turning are expressed by the above equations (14) and (15 ).

From the formulas (14) and (15), the centrifugal force a ₀ acting on the vehicle body when turning is expressed by the following formula (24).
a ₀ = ν ² / r (24)
Further, from FIG. 14, the turning radius r is expressed by the following equation (25).
r = L _H / tan δ Formula (25)
Here, since the link angle limit value is η _lim , the maximum centrifugal force a _max that can act on the vehicle body when turning, that is, the maximum centrifugal force value a _max that the vehicle body can withstand is given by the following equation (26). expressed.
a _max = g tan η _lim = ν ² / r (26)
In addition, g is a gravitational acceleration.

From the equation (26), the following equation (27) can be obtained.
r = ν ² / (g tan η _lim ) (27)
Here, the maximum value of the steering angle calculated from the vehicle speed ν and the link angle limit value η _{lim is} assumed to be δ _max . Further, the ratio between the steering wheel angle limit value δ _stlim and the maximum steering angle value δ _max is defined as the variable reduction ratio γ by the following equation (28).
γ = δ _stlim / δ _max Formula (28)
Then, the variable reduction ratio γ is expressed by the following equation (29) from the equations (25), (27), and (28).
γ = δ _stlim / tan ⁻¹ (L _H / r)
= Δ _stlim / tan ⁻¹ (gL _H tan η _lim / ν ² ) (29)
Here, since the steering wheel angle limit value δ _stlim , the gravitational acceleration g, the wheel base L _H, and the link angle limit value η _lim are constants, the variable reduction ratio γ depends on the vehicle speed ν from the above equation (29). You can see that it changes.

FIG. 15 shows the relationship between the variable reduction ratio γ calculated based on the equation (29) and the vehicle speed ν. FIG. 15 shows the steering wheel angle limit value δ _stlim : 45 degrees, the link angle limit value η _lim : 30 degrees, the center of gravity height: 0.7 [m], and the tread (between the ground contact points of the left and right wheels 12L and 12R). Distance): a result of calculation using the vehicle 10 of 0.5 [m] as a model.

  In FIG. 15, ◆ indicates the value of the variable reduction ratio γ when the tread is not considered, and Δ indicates the value of the variable reduction ratio γ when the tread is considered. As described above, the variable speed reduction ratio γ is a coefficient for reducing the actual steering angle of the wheel 12F with respect to the steering wheel angle in order to maintain the stability of the vehicle body during turning. If the intersection of the gravitational force vector extension line and the road surface 18 is between the ground contact points of the left and right wheels 12L and 12R, the balance of the vehicle body will not be lost. As a result, the variable reduction ratio γ can be set smaller. Therefore, Δ is smaller than ◆ at the same vehicle speed. Actually, when setting the value of the variable reduction ratio γ, it is desirable to set it within the range between ◆ and Δ.

  In FIG. 15, the curve indicated by the solid line indicates the minimum turning radius corresponding to the variable reduction ratio γ when the tread is not considered, and the curve indicated by the broken line is the variable reduction ratio when the tread is considered. The minimum turning radius corresponding to γ is shown.

  When the calculation is made based on the equation (29), the value of the variable reduction ratio γ becomes negative in a range where the vehicle speed ν is low (for example, a range of about 10 km / h). Therefore, in the range where the value of the variable reduction ratio γ is negative, it is desirable to set the value of the variable reduction ratio γ to +1 as shown in FIG.

Subsequently, the steering control unit 66 calculates the steering angle target value δ ^* (step S58). The steering angle target value δ ^* is calculated by the following equation (30).
δ ^* = δ _st / γ Expression (30)
By the way, when the acceleration of the steering angle target value δ ^* increases, the angular acceleration of the vehicle body, that is, the yaw rate differential value as the turning angular acceleration also increases accordingly, but when the yaw rate differential value exceeds the limit value, the vehicle body It becomes unstable.

Therefore, in the present embodiment, the vehicle body is stabilized by adjusting the change amount of the variable reduction ratio γ so as not to exceed the limit value of the angular velocity of the link angle η. Specifically, the steering angle target value δ ^* calculated by the equation (30) is adjusted so that the link angular acceleration prediction value is not more than the limit value of the yaw rate differential value.

When the limit value of the yaw rate differential value is Δψ _Max , the limit value Δψ _Max is calculated as follows.

  As shown in FIG. 16, it is considered that the vehicle body becomes unstable when the position of the center of gravity M of the vehicle 10 is out of a predetermined controllable range, that is, a stable range, in the horizontal plane. The center of gravity M is the total center of gravity including not only the vehicle 10 but also the occupant on board and the loaded object.

  The predetermined range is a range in which an extension is defined by a line segment connecting the contact points of the wheels 12, and is a polygon formed by a line segment connecting the contact points of the wheels 12. The polygon is a quadrangle when the vehicle 10 is a four-wheel vehicle, and a triangle when the vehicle 10 is a tricycle. In the present embodiment, as shown in FIG. 16 (a), the polygon has apexes at the grounding point of the wheel 12F that is the front wheel and the grounding points of the left and right wheels 12L and 12R that are the rear wheels. An isosceles triangle K.

In FIG. 16, h is the height of the center of gravity M, that is, the distance from the road surface 18 to the center of gravity M. L is a horizontal component of the distance from the ground contact point of the wheel 12F to the center of gravity M. W is the distance between the treads, that is, the ground contact points of the wheels 12L and 12R that are the left and right rear wheels. Further, W _l is the left and right stable distance at the position of the center of gravity M, corresponds to the distance between two opposite sides of the isosceles triangle K at the position of the center of gravity M, and is represented by the following equation (31).
W _l = _l W / L _H Formula (31)
Further, since the inclination angle of the vehicle body with respect to the vertical axis at the time of turning is equal to the link angle η, the component force of the centrifugal force a ₀ acting on the center of gravity M and the component force of gravity are balanced as shown in FIG. If so, the equations (11) to (13) are established.

When subjected to the maximum centrifugal force a _max capable of acting on the vehicle body during turning, is that the axis of the vector representing the resultant force of the centrifugal force a _max and the gravity g is passed through the road surface 18, facing the isosceles triangle K Since it is considered to be on two sides, when the corresponding link angle is η _Max , the following equation (32) is established.
tan η _Max = W _l / 2h = a _max / g (32)
From the equation (32), the following equation (33) is derived.
a _max = g sin (tan ⁻¹ (W _l / 2h)) (33)
Since the centrifugal force a ₀ acting on the center of gravity M at the height h is considered to be equal to a value obtained by multiplying the turning angular acceleration Δψ by the height h, the following equation (34) is established.
a _max = Δψ _Max h Formula (34)
From the equation (34) and the equations (31) and (33), the following equation (35) is derived.
Δψ _Max = (g / h) sin (tan ⁻¹ (lW / 2hL _H )) Equation (35)
Further, the following equation (36) is derived from the equations (24) and (25).
a ₀ = (ν ² / L _H ) tan δ Formula (36)
From the equation (36) and the equation (13), the inclination angle with respect to the vertical axis of the vehicle body at the time of turning, that is, the link angle predicted value η _target as the target value of the link angle η is expressed by the following equation (37 ).
η _target = tan ⁻¹ ((ν ² / gL _H ) tan δ) Expression (37)
Therefore, the steering control unit 66 calculates the link angle predicted value η _target by the equation (37) (step S59).

Subsequently, the steering control unit 66 acquires a control cycle T _S (step S60).

  Subsequently, the steering control unit 66 acquires a link angle sensor value η that is a value of the link angle detected by the link angle sensor 25a (step S61).

Then, the steering control unit 66 differentiates the link angle prediction value eta _target, calculates the link angular velocity estimated value .DELTA..eta _target (step S62). Here, the predicted link angular velocity value Δη _target is calculated by the following equation (38).
Δη _target = (η _target −η) / T _S Equation (38)
Subsequently, the steering control unit 66 makes a η _old call (step S63). η _old is a link angle sensor value η stored when the vehicle body tilt control process is executed last time. In the initial setting, η _old = 0.

Subsequently, the steering control unit 66 calculates the link angular velocity Δη by differentiating the link angle sensor value η (step S64). Here, the link angular velocity Δη is calculated by the following equation (39).
Δη = (η−η _old ) / T _S Formula (39)
And the steering control part 66 is preserve | saved as (eta) _old = (eta) (step S65). That is, the link angle sensor value η detected during the execution of the vehicle body tilt control process this time is stored in the storage means as η _old .

Then, the steering control unit 66, by differentiating the link angular velocity estimated value .DELTA..eta _target, calculates the link angular acceleration prediction value Δ ² η _target (step S66). Here, the predicted link angular acceleration value Δ ² η _target is calculated by the following equation (40).
Δ ² η _target = (Δη _target −Δη) / T _S Formula (40)
Subsequently, the steering control unit 66 acquires a steering angle sensor value δ that is a value of the steering angle detected by the steering angle sensor 63 (step S67).

Subsequently, the steering control unit 66 makes a δ _old call (step S68). δ _old is a steering angle sensor value δ stored when the vehicle body tilt control process is executed last time. In the initial setting, δ _old = 0.

Subsequently, the steering control unit 66 differentiates the steering angle sensor value δ to calculate the steering angular velocity Δδ (step S69). Here, the steering angular velocity Δδ is calculated by the following equation (41).
Δδ = (δ−δ _old ) / T _S Formula (41)
And the steering control part 66 is preserve | saved as (delta) _old = (delta) (step S70). That is, the steering angle sensor value δ detected at the time of executing the vehicle body tilt control process is stored as δ _old in the storage unit.

Subsequently, the steering control unit 66 determines whether or not the predicted link angular acceleration value Δ ² η _target is less than the maximum turning angular acceleration value Δψ _Max (step S71). Note that the maximum value Δψ _Max of the turning angular acceleration can be said to be a value representing the limit value of the link angular acceleration Δ ² η.

If the predicted link angular acceleration value Δ ² η _target is not less than the maximum turning angular acceleration value Δψ _Max , the steering control unit 66 recalculates the steering angle target value δ ^* (step S72). In this case, the steering angle target value δ ^* is recalculated by the following equation (42).
δ ^* = δ + ΔδT _S Formula (42)
When the predicted link angular acceleration value Δ ² η _target is less than the maximum value Δψ _Max of the turning angular acceleration, the steering angle target value δ ^* is not recalculated, and is calculated by the equation (30). The steering angle target value δ ^* is used as it is.

Finally, the steering control unit 66 outputs the calculated steering angle target value δ ^* to the steering motor control unit 67 (step S73), and ends the steering control process.

Thus, in the present embodiment, control is performed so that the change amount of the variable reduction ratio does not exceed the limit value of the link angular acceleration of the link mechanism 30. That is, the steering wheel steering that the steering motor 65 as the steering actuator device changes with respect to the steering angle sensor value δ _st that is the steering angle value that is input by operating the steering bar 41a as the steering device. The reduction ratio of the target angle value δ ^* , that is, the amount of change in the variable reduction ratio γ as the steering angle reduction ratio does not exceed the limit value of the link angular acceleration.

  As a result, even when sudden deceleration is performed during a turn, the change in the variable reduction ratio γ does not become too large, so that the stability of the vehicle 10 does not deteriorate.

The variable reduction ratio γ is controlled according to the vehicle speed ν so that the link angle η does not exceed the link angle limit value η _lim . Therefore, even when the vehicle speed ν is high, the stability of the vehicle body can be maintained and the turning performance can be improved.

Further, the variable reduction ratio γ is controlled to increase as the vehicle speed ν increases. For example, as shown in FIG. 15, the value of the variable reduction ratio γ is changed according to the vehicle speed ν. Thereby, the steering angle target value δ ^* can be appropriately controlled.

  In addition, this invention is not limited to the said embodiment, It can change variously based on the meaning of this invention, and does not exclude them from the scope of the present invention.

  The present invention can be used for a vehicle having at least a pair of left and right wheels.

DESCRIPTION OF SYMBOLS 10 Vehicle 11 Boarding part 12F, 12L, 12R Wheel 20 Main-body part 25 Link motor 30 Link mechanism 41a Handlebar 65 Steering motor

Claims (4)

A vehicle body including a steering unit and a main body unit coupled to each other;
A wheel rotatably attached to the steering unit, and a steerable steering wheel for steering the vehicle body;
Non-steering wheels that are rotatably attached to the main body and are not steerable;
A steering device for inputting a steering angle command;
A link mechanism for tilting the steering part or the main body part in a turning direction;
An inclination actuator device for operating the link mechanism;
A steering actuator device for changing a steering angle of the steered wheel based on a steering angle command input from the steering device;
A control device for controlling the tilt actuator device and the steering actuator device;
The control device adjusts a target value of a steering angle that changes when a reduction ratio of a steering angle of the steered wheel with respect to the steering angle command is changed, and a predicted link angular acceleration value of the link mechanism is a limit of a link angular acceleration . A vehicle characterized by controlling the steering actuator device so as not to exceed a value.   The control device calculates a link angular velocity prediction value of the link mechanism from a link angle prediction value of the link mechanism and a current value of the link angle, and based on the link angular velocity prediction value and the current value of the link angular velocity of the link mechanism. The vehicle according to claim 1, wherein a link angular acceleration predicted value of the link mechanism is calculated, and the link angular acceleration predicted value is compared with a limit value of the link angular acceleration. When the predicted link angular acceleration is equal to or greater than the limit value of link angular acceleration, the control device multiplies the current value of the steering angle of the steered wheel by the amount of change per unit time of the steering angle by unit time. vehicle according to claim 2 for controlling the steering actuator device value a value obtained by adding, as a target value of the steering angle of the steering wheel.   The vehicle according to any one of claims 1 to 3, wherein the control device sets the reduction ratio of the steering angle so as to increase as the vehicle speed increases.

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