JP2007168602A - Two-wheel traveling carriage - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To ride over an obstacle in a stable posture by posture control in a two-wheel traveling carriage. <P>SOLUTION: In an operation to run over a step, the two-wheel traveling carriage moves a plummet member 20 to the direction of a driving wheel 2a for example, and makes the driving wheel 2b run over the step 100 in advance. After the driving wheel 2b runs over the step 100, the two-wheel traveling carriage moves the plummet member 20 in the direction of the driving wheel 2b, and makes the driving wheel 2b run over the step 100. Since the carriage makes the driving wheels run over the step one by one, torque is applied to each driving wheel 2a, 2b one by one. When one side driving wheel runs over the step, the center of gravity of the vehicle body is moved to the direction of the other driving wheel. Therefore, the driving wheel to run over the obstacle can run over the obstacle with smaller torque. Accordingly, the influence of the reaction caused by the torque applied to the driving wheel becomes small, and the posture of the vehicle body can be avoided from being largely disturbed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a two-wheeled moving carriage overcoming an obstacle in a state in which the vehicle body is posture controlled.

  In some two-wheeled moving carts, the posture is controlled by rotating drive wheels arranged on the left and right sides on the same axis orthogonal to the traveling direction.

  When such a two-wheeled moving vehicle finds an obstacle such as a step in front of it and gets over the obstacle, torque is applied to both wheels so that both wheels get over the obstacle almost simultaneously with the body controlled. Was controlled.

  There is known a moving cart that can stably climb over a high step in a moving cart having a plurality of wheels, although it is not a two-wheel vehicle (see, for example, Patent Document 1). The moving carriage includes a center of gravity moving means for moving the center of gravity of the base on a carriage base having a plurality of wheels. Moreover, the said mobile trolley has a pair of wheel support part arrange | positioned so that rocking | fluctuation is possible on the right and left of a base, and a pair of wheel is arrange | positioned before and behind each wheel support part. When going over the step, the center of gravity of the carriage is moved backward by the center of gravity moving means. In addition, the wheel support portion that supports the front wheel that hits the step is swung by the swing driving means, and the front wheel is lifted upward. Thereafter, when the other front wheel hits a step as the carriage advances, the other front wheel is lifted. After both wheels are lifted, the carriage further advances, both rear wheels ride on the steps, and the carriage gets over the steps.

In addition, an automatic guided vehicle that can easily pass through a stepped portion is known (see, for example, Patent Document 2). The control device for the automatic guided vehicle detects a mark plate provided in the step area by a sensor, and detects entry into the step area by the detection. In such a case, the control unit of the control device cuts the steering wheel slightly via the steering motor, and fixes it in this state and enters the stepped portion, so that the unmanned conveyance is performed obliquely with respect to the stepped portion. Control the car to enter.
JP 2003-285743 A Japanese Utility Model Publication No. 6-30807

  However, in the prior art, torque is applied to both wheels and the obstacles are overcome at the same time. Therefore, a large force is applied to the vehicle body due to the reaction of the torque applied to both wheels. This force could greatly disturb the posture of the vehicle body. For this reason, posture control when overcoming a step is difficult.

  Moreover, in the technique described in Patent Document 1, in a moving carriage that is moved by a plurality of driving wheels arranged at the front and back, a step can be stably overcome, but two drives arranged on the left and right on the same axis. In a two-wheeled carriage that is moved by a wheel, there is a case where the step cannot be overcome with a stable posture while performing posture control.

  Further, in the technique described in Patent Document 2, the edge of the stepped portion and the wheel of the automatic guided vehicle are in point contact, and the stepped portion can be easily passed. When getting over, there was a risk of posture falling and falling.

  The present invention has been made to solve the above-described problems of the conventional example, and an object of the present invention is to provide a two-wheel moving carriage capable of getting over obstacles in a stable posture under posture control.

  In order to achieve the above object, the invention of claim 1 is directed to drive wheels arranged on the left and right on the same axis, control means for driving and controlling the drive wheels, and detection for detecting an obstacle ahead of the drive wheels. Means for measuring the height of the obstacle detected by the detection means, and the height of the obstacle measured by the measurement means is within a range that can be overcome. Determination means for determining whether or not there is an obstacle, and when the determination means determines that the height of the obstacle is within a range that can be overcome by the determination means, the obstacle is applied to the drive wheel. The drive wheel is driven and controlled so as to get over the object one wheel at a time.

  According to a second aspect of the present invention, there is provided a two-wheel vehicle comprising: drive wheels arranged on the left and right on the same axis; control means for driving and controlling the drive wheels; and detection means for detecting an obstacle ahead of the drive wheels. In the mobile carriage, the measuring means for measuring the height of the obstacle detected by the detecting means, and determining whether or not the height of the obstacle measured by the measuring means is within a range that can be overcome. A determining means; and a gravity center moving means for moving the center of gravity of the carriage in the coaxial direction. The control means is determined by the determining means to be within a range in which the height of the obstacle can be overcome. When the driving wheel is controlled to drive the obstacle over the driving wheel one by one, the center-of-gravity movement means is driven by one driving wheel over the obstacle based on a signal from the control means. When the other It is intended to move the center of gravity in the direction of the driving wheels.

  According to the first aspect of the present invention, since the drive wheels are controlled so that the obstacles get over the obstacles one by one, the posture of the vehicle body is hardly disturbed by the reaction of the torque applied to the drive wheels. For this reason, it is possible to get over obstacles in a stable posture.

  According to the second aspect of the present invention, since the driving wheel is controlled so that the obstacle gets over the obstacle one by one, the posture of the vehicle body is hardly disturbed by the reaction of the torque applied to the driving wheel. For this reason, it is possible to get over obstacles in a stable posture.

  Also, when one drive wheel gets over an obstacle, the center of gravity of the vehicle body moves in the direction of the other drive wheel, so the drive wheel over the obstacle is driven with a smaller torque, and the obstacle is placed on the drive wheel. Can be overcome. Since the driving wheel is driven with a smaller torque, the disturbance of the posture due to the reaction of the torque can be reduced, and the obstacle can be overcome with a stable posture.

  A two-wheeled carriage according to a first embodiment of the present invention will be described with reference to FIGS. 1 (a), (b), (c), and (d) show the configuration of a two-wheeled moving carriage (hereinafter referred to as a moving carriage). The movable carriage 1 includes drive wheels 2a and 2b arranged on the left and right on the same axis, motors 3a and 3b for driving the drive wheels 2a and 2b, and drive forces of the motors 3a and 3b, respectively. Rotating shafts 4a and 4b transmitted to 2b. The motors 3 a and 3 b are arranged in the housing 5. The drive wheels 2a and 2b are respectively attached to different rotating shafts 4a and 4b arranged on the same axis.

  The movable carriage 1 also includes ultrasonic sensors 6a and 6b (detection means and measurement means) that detect obstacles ahead of the drive wheels 2a and 2b and measure the height of the detected obstacles. The ultrasonic sensors 6a and 6b are held by holding members 7a and 7b, respectively.

  FIG. 2 shows an electrical configuration of the mobile carriage 1. The mobile carriage 1 includes a gyro sensor 10 and an acceleration sensor 11 that detect the posture of the vehicle body, a speed sensor 12 that measures the vehicle speed, an operation unit 15 that is used by the user to operate the mobile carriage 1, and the presence of obstacles. Ultrasonic sensors 6a and 6b that detect and measure the height of the obstacle are provided. Moreover, the movable carriage 1 has motors 3a and 3b that rotate the drive wheels 2a and 2b, and a motor drive unit 14 that controls driving of the motors 3a and 3b, and further includes a control unit 13 that controls the sensors and the units. Prepare.

  The ultrasonic sensors 6a and 6b are circuits for detecting the presence of an obstacle such as a step in front of the drive wheels 2a and 2b and measuring the height of the detected obstacle. When detecting the presence of an obstacle, the ultrasonic sensors 6 a and 6 b output a signal based on the detection to the control unit 13 in order to stop the moving carriage 1. The ultrasonic sensors 6 a and 6 b measure the height of the obstacle and output a signal based on the measurement result to the control unit 13.

  The gyro sensor 10 is a sensor for sequentially measuring the speed at which the housing 5 (vehicle body) tilts, that is, the angular speed at which the vehicle body rotates about the rotation shafts 4a and 4b. The gyro sensor 10 sequentially outputs a signal based on the measurement result to the control unit 13. The gyro sensor 10 can respond to a quick movement of the vehicle body.

  When measuring the tilt angle of the vehicle body, it is possible to calculate the tilt angle using only the gyro sensor 10. The gyro sensor 10 sequentially measures the changing angular velocity, and the inclination angle is obtained by integrating the angular velocity obtained by the measurement. If this inclination angle is added, the final inclination angle can be calculated. The inclination angle thus obtained includes an integration error.

  The acceleration sensor 11 is a sensor for accurately obtaining the tilt angle. For example, when the acceleration sensor 11 is a piezoelectric acceleration sensor, the acceleration sensor 11 includes a piezoelectric element. When the acceleration sensor 11 is tilted from a horizontal state, the piezoelectric element is deformed by gravity. The tilt angle is measured based on this deformation. A signal based on the tilt angle is output from the acceleration sensor 11 to the control unit 13. When the acceleration sensor 11 is moved quickly, it cannot distinguish whether the output is a signal due to inertia or a signal due to gravity. For this reason, when the vehicle body moves quickly, the acceleration sensor 11 cannot obtain an accurate inclination angle.

  Two gyro sensors 10 are arranged to measure the inclination angle (roll) of the vehicle body in the left-right direction and the inclination angle (pitch) in the front-rear direction. In order to correct the output of the gyro sensor 10 that measures the tilt angle in the front-rear direction and the left-right direction, two acceleration sensors 11 are arranged in combination with the gyro sensor 10. In this way, when the vehicle body moves quickly, the control unit 13 can determine the inclination angle of the vehicle body by correcting the output of the acceleration sensor 11 using the output of the gyro sensor 10. Further, when the vehicle body moves slowly, the control unit 13 can obtain the accurate angular velocity of the vehicle body by correcting the output of the gyro sensor 10 using the output from the acceleration sensor 11.

  The speed sensor 12 sequentially measures the rotational speed of the drive wheels 2a and 2b rotated by the motors 3a and 3b. Based on the measurement, the angular speed and the vehicle speed of the drive wheels 2a and 2b are calculated. The speed sensor 12 sequentially outputs a signal based on the measurement result to the control unit 13.

  The motor drive unit 14 includes a motor drive circuit. The motor drive unit 14 drives the motors 3a and 3b based on a signal from the control unit 13. By this driving, the motors 3a and 3b are rotated at the rotation speed instructed from the control unit 13.

  The operation unit 15 is a circuit for outputting signals instructing various operations of the mobile carriage 1 to the control unit 13 based on user operations. For example, when the mobile carriage 1 is for carrying goods, the operation unit 15 includes various keys for the user to instruct various operations, and a remote controller that emits an infrared signal based on the operation of the various keys, and the remote controller. It is composed of an infrared light receiving circuit that receives the infrared signal. The operation of the movable carriage 1 instructed by the operation unit 15 to the control unit 13 includes forward, reverse, left turn, right turn, acceleration, deceleration, and stop.

  The control unit 13 includes a control circuit including a CPU. The control unit 13 (control unit) outputs a signal for controlling the rotation speed of the motors 3a and 3b to the motor drive unit 14. The drive wheels 2a and 2b are driven and controlled by controlling the rotation speeds of the motors 3a and 3b. In this way, the control unit 13 controls the drive wheels 2a and 2b.

  Further, when an obstacle is detected, the control unit 13 (determination means) determines whether or not the height of the obstacle measured by the ultrasonic sensors 6a and 6b is within a range that can be overcome. When the control unit 13 determines that the height of the obstacle is within a range in which the obstacle can be overcome, the controller 13 controls the driving wheels 2a and 2b so that the obstacles are passed over the driving wheels 2a and 2b one by one. The control unit 13 further includes a storage device such as a ROM (Read Only Memory). The storage device stores a criterion for determining whether or not an obstacle can be overcome.

  Next, a method of driving control of the driving wheels 2a and 2b by the control unit 13 will be described. The drive control is performed by controlling the drive torque that drives the drive wheels 2a and 2b. The controller 13 obtains the vehicle body inclination angle obtained from the output of each sensor, the angular velocity of the inclination angle, the angular velocity of the driving wheel 2a, the angular velocity of the driving wheel 2b, the current vehicle speed of the movable carriage 1, the target vehicle speed, the current vehicle body current. Based on the turning angle with respect to the traveling direction, the target turning angle, and the like, the driving torque is calculated by calculation. In this calculation, in order to perform posture control, the driving torque is obtained based on the inclination angle of the vehicle body and the angular velocity of the inclination angle. In addition, in order to perform attitude control and vehicle speed control, the drive torque is calculated based on the angular speed of the drive wheels 2a, the angular speed of the drive wheels 2b, the current vehicle speed, and the target vehicle speed. The target vehicle speed is set by the control unit 13 based on a signal output from the operation unit 15 by a user operation or a signal from the ultrasonic sensors 6a and 6b.

  After the calculation, the control unit 13 outputs a control signal based on the calculation result to the motor driving unit 14. The motor drive unit 14 rotates the motors 3a and 3b at a rotation speed that generates drive torque obtained by calculation based on the control signal. The drive wheels 2a and 2b are driven according to the rotational speed of the motors 3a and 3b. As described above, the control unit 13 performs drive torque control of the motors 3a and 3b and performs drive control of the drive wheels 2a and 2b by calculation based on variables necessary for posture control and vehicle speed control. As a result, posture control for maintaining the balance of the vehicle body in the front-rear direction and vehicle speed control for setting the vehicle speed to the target vehicle speed are performed simultaneously.

  With reference to FIG. 3, the attitude | position change of the mobile trolley 1 when attitude | position control is made by the control part 13 is demonstrated. The posture control of the vehicle body is performed based on signals from the gyro sensor 10, the acceleration sensor 11, and the speed sensor 12.

  When the moving carriage 1 is accelerated or moves at a constant speed, the moving carriage 1 receives a force for raising the vehicle body. Therefore, in order to prevent the vehicle body from falling in the direction opposite to the traveling direction (backward direction), the posture control is performed by the control unit 13 in order to tilt the vehicle body forward. Specifically, in accordance with the current vehicle speed measured by the speed sensor 12, the rotational speed of the drive wheels 2a and 2b is temporarily reduced to generate a force that tilts the vehicle body forward. After the vehicle body leans forward, the vehicle speed is accelerated. In this way, posture control is performed. The angle at which the vehicle body tilts forward is increased as the vehicle speed increases. The control unit 13 grasps the inclination angle of the vehicle body based on signals sequentially output from the gyro sensor 10 and the acceleration sensor 11 and controls increase / decrease of the inclination angle.

  When the movable carriage 1 is decelerated by braking, the vehicle body receives a force in the traveling direction (forward) by the inertial force. The braking is performed based on a stop instruction signal output from the operation unit 15 or the ultrasonic sensors 6a and 6b. In order to avoid falling due to inertial force, the posture of the vehicle body is controlled by the control unit 13 so as to tilt backward. Specifically, a force that tilts the vehicle body backward is generated by temporarily increasing the rotational speed of the drive wheels 2a and 2b in accordance with the current vehicle speed. After the vehicle body is tilted rearward, the vehicle speed is decelerated and posture control is performed so as not to cause the vehicle body to overturn. The control unit 13 grasps the inclination angle of the vehicle body based on signals sequentially output from the gyro sensor 10 and the acceleration sensor 11 and controls increase / decrease of the inclination angle. When the vehicle body stops, the posture of the vehicle body becomes an upright state by the posture control. While the vehicle is stopped, posture control is always performed in order to maintain a balance in the longitudinal direction of the vehicle body.

  Thus, in the mobile trolley 1, the posture of the vehicle body is always controlled regardless of whether it is moving or stopped. For example, even when the moving carriage 1 finds an obstacle such as a step and gets over the obstacle, the posture is always controlled.

  Next, with reference to FIG. 4 to FIG. 7, a method will be described in which the movable carriage 1 gets over the step (obstacle) under the above attitude control.

  4 (a), 4 (b), and 4 (c) show a preparatory operation performed before the movable carriage 1 gets over the step. For example, the case where the ultrasonic sensor 6b held by the holding member 7b detects the step 100 when the movable carriage 1 is moving (see FIG. 5A) will be described below.

  When one of the ultrasonic sensors 6a and 6b, for example, the ultrasonic sensor 6b detects the presence of the step 100, there is a preparatory operation in the mobile carriage 1 over the step 100. In the preparation operation, the drive wheels 2a and 2b are driven so that both wheels come into contact with the step 100 (see FIGS. 4B and 4C). Note that the controller 13 determines whether or not the drive wheels 2a and 2b are in contact with each other based on the motor currents of the motors 3a and 3b.

  FIG. 5 shows the procedure of the preparation operation of the mobile carriage 1. When the ultrasonic sensor 6a and / or 6b detects the step 100 (Yes in S101), the ultrasonic sensor that detects the step 100 measures the height of the step 100 (S102). When the ultrasonic sensors 6a and 6b do not detect the presence of a step (No in S101), the movable carriage 1 enters a standby state.

  First, the case where the ultrasonic sensor that detects the step 100 is only one of the ultrasonic sensors 6a and 6b (ultrasonic sensor 6a or 6b) (Yes in S103) will be described. In such a case, the control unit 13 determines whether or not the height of the step 100 is 10% or less of the radius of the drive wheels 2a and 2b. As a result of the determination, if the height of the step 100 is 10% or less of the drive wheel radius (Yes in S104), the vehicle 100 gets over the step 100 in the same direction without changing the direction of the vehicle body (S105).

  When the height of the step 100 is higher than 10% of the driving wheel radius (No in S104), the control unit 13 further determines whether or not the height of the step 100 is equal to or less than a criterion. The determination criterion is determined based on the maximum height of an obstacle that the mobile carriage 1 can get over and is stored in a storage device included in the control unit 13. Here, when the criterion is, for example, 40% of the driving wheel radius and the height of the step 100 is equal to or less than that (Yes in S106), the movable carriage 1 moves to a position where both wheels are in contact with the step 100 (S107). ). Thereafter, the step over step is started (S108). With the start of the step overstep operation, the preparatory operation ends.

  When the height of the step 100 is higher than 40% of the driving wheel radius (No in S106), the moving carriage 1 cannot get over the step 100, so the step over operation is stopped (S109). Thereafter, the preparatory operation before the step-over operation is completed.

  When both the ultrasonic sensors 6a and 6b detect the step 100 (No in S103), the control unit 13 determines whether the height of the step 100 is 10% or less of the radius of the drive wheels 2a and 2b. As a result of the determination, if the height of the step 100 is 10% or less of the driving wheel radius (Yes in S110), the vehicle goes over the step 100 in the same direction without changing the direction of the vehicle body (S105).

  When the height of the step 100 is higher than 10% of the driving wheel radius (No in S110), and the control unit 13 determines that the height of the step 100 is 40% or less of the driving wheel radius (S111). Yes), stepping over the step is started (S108). With the start of the step-over operation, the preparation operation ends.

  When the height of the step 100 is higher than 40% of the driving wheel radius (No in S111), the moving carriage 1 cannot get over the step 100, so the step over operation is stopped (S109). Thereafter, the preparatory operation before the step-over operation is completed.

  FIGS. 6A, 6B, and 6C show the step-over operation of the mobile carriage 1 that is performed after the preparation operation. In the step overstep operation, first, the control unit 13 determines whether or not the height of the step 100 is within a range where the step 100 can be overcome based on signals from the ultrasonic sensors 6a and 6b. When the control unit 13 determines that the height of the step 100 is within a range that can be overcome, torque is applied to one of the drive wheels 2a and 2b, for example, the drive wheel 2b, so as to get over the step 100 (see FIG. (See (a)). Of course, the driving wheel 2a may be moved over the step 100 first.

  After the drive wheel 2b gets over the step 100 first, the control unit 13 applies torque to the other drive wheel 2b to get over the step 100 (see FIGS. 5B and 5C). In this way, when the height of the step 100 is within a range where the step 100 can be overcome, the control unit 13 controls the drive wheels 2a and 2b so that the drive wheels 2a and 2b get over the step 100 one by one.

  By such an operation, torque is applied to each of the driving wheels 2a and 2b in order to overcome the step. For this reason, the influence of the reaction due to the torque applied to the drive wheels is reduced, and the posture of the vehicle body is less disturbed. The reason will be described. When climbing over a step, a larger torque is required than when traveling on a flat road surface at the same speed. When driving wheels are stepped over at the same time, force is applied to the vehicle body due to the reaction of this torque applied to both wheels of the driving wheels. As a result, the posture of the vehicle body may be greatly disturbed by the reaction of this torque. On the other hand, in the mobile trolley 1 of this embodiment, drive control is performed so that the drive wheels 2a and 2b get over the steps one by one. For this reason, the reaction of torque that causes the posture to be disturbed is only from one wheel. That is, the posture of the vehicle body is less disturbed by the reaction of the torque applied to the drive wheels, compared to when both wheels get over the step almost simultaneously. In this way, it is possible to overcome the step with a stable posture.

  FIG. 7 shows the procedure of the step over the step of the mobile carriage 1 that is started in S108 of FIG. In this operation, the movable carriage 1 gets over the step 100 one wheel at a time. Even during step-over operation, the vehicle body posture is always controlled.

  Of the driving wheels 2a and 2b, for example, when the driving wheel 2b first climbs over the step 100 (Yes in S201), the control unit 13 drives the motor 3b to apply torque to the driving wheel 2b, and the step 100 is stepped first. Get over (S202). The controller 13 determines whether or not the drive wheel 2b has overcome the step 100 based on the output from the acceleration sensor 11 that measures the roll. When the drive wheel 2b gets over the step 100, the movable carriage 1 stops temporarily. At this time, the drive wheel 2 a is in contact with the step 100.

  After the driving wheel 2b gets over the step 100, the control unit 13 drives the motor 3a to apply torque to the driving wheel 2a to get over the step 100 (S203). The control unit 13 determines whether or not the driving wheel 2a has overcome the step 100 based on the output from the acceleration sensor 11 that measures the roll. When the control unit 13 determines that both wheels have climbed over the step 100, the step climbing operation ends.

  When the driving wheel 2b does not go over the step 100 first, that is, when the driving wheel 2a goes over the step 100 first (No in S201), the control unit 13 drives the motor 3a to apply torque to the driving wheel 2a, First, the step 100 is overcome (S204). The control unit 13 determines whether or not the driving wheel 2a has overcome the step 100 based on the output from the acceleration sensor 11 that measures the roll. When the drive wheel 2a gets over the step 100, the movable carriage 1 stops temporarily. At this time, the drive wheel 2 b is in contact with the step 100.

  After the driving wheel 2a gets over the step 100, the control unit 13 drives the motor 3b to apply torque to the driving wheel 2b to get over the step 100 (S205). The controller 13 determines whether or not the drive wheel 2b has overcome the step 100 based on the output from the acceleration sensor 11 that measures the roll. When the control unit 13 determines that both wheels have climbed over the step 100, the step climbing operation ends.

  According to such an operation procedure, the drive wheels 2a and 2b are driven and controlled so as to get over the steps such as the steps one by one, so that the vehicle body is not greatly disturbed by the reaction of the torque applied to the drive wheels. For this reason, it is possible to get over obstacles in a stable posture.

  Next, a two-wheeled carriage according to a second embodiment of the present invention will be described with reference to FIGS. This embodiment is different from the first embodiment in that the movable carriage 1 further includes a center of gravity moving unit that moves the center of gravity of the carriage.

  FIGS. 8A, 8 </ b> B, 8 </ b> C, and 8 </ b> D show the configuration of the mobile carriage 1. The moving carriage 1 of this embodiment is different from the moving carriage 1 of the first embodiment (see FIG. 1) in that it further includes a center of gravity moving part (center of gravity moving means). The center-of-gravity moving unit includes a weight member 20, a pedestal 21 on which the weight member 20 is placed, a drive wheel 22 for movably providing the pedestal 21, and a rail 23 for moving the pedestal 21 in the coaxial direction. The center-of-gravity moving unit further includes an axle 24 for rotating the drive wheel 22 and a motor unit 25 for rotating the axle 24.

  The weight member 20 is a member for moving the center of gravity of the movable carriage 1, and is composed of, for example, a battery that is a power source of the movable carriage 1. The pedestal 21 is a plate-like member for mounting and fixing the weight member 20 on the upper surface. The pedestal 21 is movably provided and moves along the rail 23 by the rotation of the drive wheel 22. The rail 23 is disposed in parallel to the coaxial direction (hereinafter abbreviated as the coaxial direction) of the drive wheels 2a and 2b. The drive wheels 22 are composed of, for example, four wheels, and are fixed two by two by two axles 24. The two motor units 25 support the two axles 24 in a rotatable manner. Further, the axles 24 are respectively rotated by a motor (not shown) included in the motor unit 25. Only one of the two motor units 25 may have a motor for rotating the axle 24 or both may have a motor.

  Since it is configured as described above, when the motor of the motor unit 25 rotates the axle 24, the drive wheels 22 rotate. When the drive wheel 22 rotates, the pedestal 21 moves along the rail 23. As the pedestal 21 moves, the weight member 20 moves in the coaxial direction of the drive wheels 2a, 2b. As the weight member 20 moves in the coaxial direction, the center of gravity of the movable carriage 1 moves in the coaxial direction.

  The moving range of the weight member 20 is a vehicle width including the widths of the drive wheels 2a and 2b, for example. In order to ensure this vehicle width, the housing 5 has an opening 10 on the side surface. The weight member 20 is taken in and out from the opening 10 by a motor.

  FIG. 9 shows an electrical configuration of the mobile carriage 1. Compared with the electrical configuration of the mobile carriage 1 of the first embodiment (see FIG. 2), the electrical configuration of the mobile carriage 1 of this embodiment includes a center of gravity moving unit 26 for moving the center of gravity of the mobile carriage 1. Furthermore, it differs in having it.

  The center-of-gravity moving unit 26 operates based on a signal from the control unit 13. When the control unit 13 instructs the center-of-gravity movement unit 26 to move the center of gravity, the motor of the motor unit 25 rotates the drive wheels 22 based on the instruction. As the drive wheel 22 rotates, the weight member 20 moves in the coaxial direction. With such a configuration, the center of gravity of the movable carriage 1 is moved in the coaxial direction.

  Next, with reference to FIG. 10 to FIG. 12, a method for the moving carriage 1 to get over the step and a method for moving the center of gravity when stepping over the step will be described under posture control.

  FIGS. 10A, 10B, and 10C show a preparatory operation performed before the movable carriage 1 gets over the step. For example, the case where the ultrasonic sensor 6b held by the holding member 7b detects the step 100 when the movable carriage 1 is moving (see FIG. 5A) will be described below.

  When one of the ultrasonic sensors 6a and 6b, for example, the ultrasonic sensor 6b detects the presence of the step 100, there is a preparatory operation in the mobile carriage 1 over the step 100. In the preparation operation, the drive wheels 2a and 2b are driven so that both wheels come into contact with the step 100 (see FIGS. 10B and 10C). Note that the controller 13 determines whether or not the drive wheels 2a and 2b are in contact with each other based on the motor currents of the motors 3a and 3b.

  FIGS. 11A, 11B, and 11C show the step-over operation of the mobile carriage 1 that is performed after the preparation operation. In the step overstep operation, first, the control unit 13 determines whether or not the height of the step 100 is within a range where the step 100 can be overcome based on signals from the ultrasonic sensors 6a and 6b. When the control unit 13 determines that the height of the step 100 is within a range that can be overcome, the control unit 13 causes one of the drive wheels 2a and 2b to get over the step 100, for example, the drive wheel 2b (see FIG. 5A). ). Of course, the driving wheel 2a may be moved over the step 100 first.

  When the drive wheel 2b gets over the step 100, the motor of the motor unit 25 is driven based on an instruction from the control unit 13, and the weight member 20 is moved in the direction of the drive wheel 2a. The weight member 20 advances to the outside from the opening 10 on the side surface of the housing 5. In this way, the center of gravity of the movable carriage 1 is moved in the direction of the drive wheel 2a. After the movement of the center of gravity, the driving wheel 2b is driven by the motor 3b and gets over the step 100. A stopper may be provided in the housing 5 in order to prevent the weight member 20 from sliding out of the housing 5.

  After the drive wheel 2b gets over the step 100 first, the control unit 13 makes the other drive wheel 2a get over the step 100 (see FIG. 11B). When the drive wheel 2a gets over the step 100, the motor of the motor unit 25 is driven based on an instruction from the control unit 13, and the weight member 20 is moved in the direction of the drive wheel 2b. The weight member 20 advances to the outside from the opening 10 on the side surface of the housing 5. In this way, the center of gravity of the movable carriage 1 is moved in the direction of the drive wheel 2b. After the movement of the center of gravity, the drive wheel 2a is driven by the motor 3a and gets over the step 100. After overcoming the step, the weight member 20 is moved to the original position (see FIG. 11C).

  As described above, when the height of the step is within a range where the step can be overcome, the control unit 13 drives and controls the drive wheels 2a and 2b so that the drive wheels 2a and 2b get over the step one by one. Torque is applied to each of the driving wheels 2a and 2b in order to overcome the step by such a step-over method. For this reason, the influence of the reaction due to the torque applied to the drive wheels is small, and the posture of the vehicle body can be avoided from being greatly disturbed.

  Further, based on an instruction from the control unit 13, the center-of-gravity moving unit 26 moves the center of gravity of the vehicle body in the direction of the other driving wheel when one driving wheel gets over the step. For this reason, the center of gravity moves in the direction of the drive wheel that remains in place. Therefore, the drive wheel that gets over the obstacle can get over the obstacle with a smaller torque. Since the driving wheel is driven with a smaller torque, the disturbance of the posture due to the reaction of the torque can be reduced, and the obstacle can be overcome with a stable posture.

  FIG. 12 shows a procedure for moving over the steps of the moving carriage 1 and a procedure for moving the center of gravity. This figure shows the procedure of the step overstep operation started in S108 of FIG. In this operation, the movable carriage 1 gets over the step 100 one wheel at a time. Even during step-over operation, the vehicle body posture is always controlled.

  Of the driving wheels 2a and 2b, when the driving wheel 2b first gets over the step 100 (Yes in S301), the gravity center moving unit 26 moves the weight member 20 based on a signal from the control unit 13 instructing movement of the center of gravity. It is moved in the direction of the drive wheel 2a (S302). Thereafter, the control unit 13 drives the motor 3b to apply torque to the drive wheel 2b, and first gets over the step 100 (S303). The controller 13 determines whether or not the drive wheel 2b has overcome the step 100 based on the output from the acceleration sensor 11 that measures the roll. When the drive wheel 2b gets over the step 100, the movable carriage 1 stops temporarily. At this time, the drive wheel 2 a is in contact with the step 100.

  After the drive wheel 2b gets over the step 100, the gravity center moving unit 26 moves the weight member 20 in the direction of the drive wheel 2b based on the signal from the control unit 13 instructing the movement of the center of gravity (S304). Thereafter, the control unit 13 drives the motor 3a to apply torque to the driving wheel 2a to get over the step 100 (S305). The control unit 13 determines whether or not the driving wheel 2a has overcome the step 100 based on the output from the acceleration sensor 11 that measures the roll. When the control unit 13 determines that both wheels have climbed over the step 100, the step climbing operation ends.

  When the driving wheel 2b does not go over the step 100 first, that is, when the driving wheel 2a goes over the step 100 first (No in S301), the gravity center moving unit 26 receives a signal from the control unit 13 instructing movement of the center of gravity. Based on this, the weight member 20 is moved in the direction of the drive wheel 2b (S306). Thereafter, the control unit 13 drives the motor 3a to apply torque to the drive wheels 2a, and first gets over the step 100 (S307). The control unit 13 determines whether or not the driving wheel 2a has overcome the step 100 based on the output from the acceleration sensor 11 that measures the roll. When the drive wheel 2a gets over the step 100, the movable carriage 1 stops temporarily. At this time, the drive wheel 2 b is in contact with the step 100.

  After the driving wheel 2a gets over the step 100, the center-of-gravity moving unit 26 moves the weight member 20 in the direction of the driving wheel 2a based on the signal from the control unit 13 instructing the movement of the center of gravity (S308). Thereafter, the control unit 13 drives the motor 3b to apply torque to the drive wheel 2b to get over the step 100 (S309). The controller 13 determines whether or not the drive wheel 2b has overcome the step 100 based on the output from the acceleration sensor 11 that measures the roll. When the control unit 13 determines that both wheels have climbed over the step 100, the step climbing operation ends.

  According to such an operation procedure, the drive wheels 2a and 2b are driven and controlled so as to get over the steps such as the steps one by one, so that the vehicle body is not greatly disturbed by the reaction of the torque applied to the drive wheels. For this reason, it is possible to get over obstacles in a stable posture.

  Further, based on an instruction from the control unit 13, the center-of-gravity moving unit 26 moves the center of gravity of the vehicle body in the direction of the other driving wheel when one driving wheel gets over the step. For this reason, the center of gravity moves in the direction of the drive wheel that remains in place. Therefore, the drive wheel that gets over the obstacle can get over the obstacle with a smaller torque. Since the driving wheel is driven with a smaller torque, the disturbance of the posture due to the reaction of the torque can be reduced, and the obstacle can be overcome with a stable posture.

  As mentioned above, although embodiment which applied this invention was described, this invention is not limited to such embodiment, Various deformation | transformation is possible according to a use purpose. For example, the criterion for determining whether or not the step 13 can get over the step is not limited to 40% of the radius of the driving wheel, and can be changed within a range that the moving carriage 1 can get over. Further, in the center of gravity moving unit 26, what is fixed to the axle 24 may be a gear instead of the drive wheel 22.

(A) is a front view which shows the structure of the two-wheeled moving trolley | bogie which concerns on 1st embodiment of this invention, (b) is the left view of (a), (c) is the right view of (a), (d ) Is a plan view of (a). The block diagram which shows the electrical constitution of the said two-wheeled moving trolley | bogie. The figure which shows the attitude | position change at the time of the movement of the said two-wheeled moving trolley | bogie. (A) is a plan view showing a state where one of the two ultrasonic sensors of the two-wheel mobile carriage has detected a step, and (b) is a state where the two-wheel mobile carriage has moved to a position where both wheels are in contact with the step. (C) is a left side view of the same figure (b). The flowchart which shows the procedure of the preparation operation | movement before level | step difference operation | movement of the said two-wheeled moving trolley | bogie. (A) is a plan view showing a state when one driving wheel of the two-wheeled moving carriage gets over the step, and (b) is a plan view showing a state when the other driving wheel of the two-wheeled moving carriage gets over the step. (C) is a top view which shows a mode that both wheels of the said two-wheeled moving trolley got over the level | step difference. The flowchart which shows the procedure of level | step difference operation | movement of the said two-wheeled moving trolley | bogie. (A) is a front view which shows the structure of the two-wheeled moving trolley | bogie which concerns on 2nd embodiment of this invention, (b) is the left view of (a), (c) is the right view of (a), (d ) Is a plan view of (a). The block diagram which shows the electrical constitution of the said two-wheeled moving trolley | bogie. (A) is a plan view showing a state where one of the two ultrasonic sensors of the two-wheel mobile carriage has detected a step, and (b) is a state where the two-wheel mobile carriage has moved to a position where both wheels are in contact with the step. (C) is a left side view of the same figure (b). (A) is a plan view showing a state when one driving wheel of the two-wheeled moving carriage gets over the step, and (b) is a plan view showing a state when the other driving wheel of the two-wheeled moving carriage gets over the step. (C) is a top view which shows a mode that both wheels of the said two-wheeled moving trolley got over the level | step difference. The flowchart which shows the procedure of level | step difference operation | movement of the said two-wheeled moving trolley | bogie.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile trolley 2a, 2b Drive wheel 3a, 3b Motor 6a, 6b Ultrasonic sensor 10 Gyro sensor 11 Acceleration sensor 12 Speed sensor 13 Control part 14 Motor drive part 20 Weight member 21 Base 22 Drive wheel 23 Rail 24 Axle 25 Motor part 26 Center of gravity movement

Claims (2)

Driving wheels arranged on the left and right on the same axis;
Control means for driving and controlling the drive wheels;
In the two-wheeled mobile carriage provided with detection means for detecting an obstacle in front of the drive wheel,
Measuring means for measuring the height of the obstacle detected by the detecting means;
Determination means for determining whether or not the height of the obstacle measured by the measurement means is within a range that can be overcome, and
The control means controls driving of the driving wheel so that the obstacle gets over the driving wheel one wheel at a time when the judging means determines that the height of the obstacle is within a range that can be overcome. A two-wheeled moving cart characterized by that. Driving wheels arranged on the left and right on the same axis;
Control means for driving and controlling the drive wheels;
In the two-wheeled mobile carriage provided with detection means for detecting an obstacle in front of the drive wheel,
Measuring means for measuring the height of the obstacle detected by the detecting means;
Determining means for determining whether or not the height of the obstacle measured by the measuring means is within a range that can be overcome;
A center of gravity moving means for moving the center of gravity of the carriage in the coaxial direction; and
The control means controls driving of the driving wheel so that the obstacle gets over the driving wheel one wheel at a time when the judging means determines that the height of the obstacle is within a range that can be overcome. And
The center-of-gravity moving means moves the center of gravity in the direction of the other drive wheel when one drive wheel gets over the obstacle based on a signal from the control means.

Images