JP2009202761A - Mobile robot and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a movable robot capable of safely and promptly executing with simple operation a grounding control of wheels situated at both ends of a turning leg part arranged at the tip of a multi-joint leg wheel, and its control method. <P>SOLUTION: A movable robot is equipped with a turning leg part 11 supported on a vehicle body 2 so as to be turnable around a horizontal shaft and fixable, a multi-joint leg wheel 10 which keeps at both ends the drive wheels 13 fixably rotating in a regular and reverse directions and which includes a turning leg part 20 keeping the center part supported so as to be fixable and turnable around the horizontal shaft with respect to the tip of the turning leg part 11, and a ground detection sensor 15 for determining a ground state of the drive wheels 13. The ground detection sensor 15 controls a grounded wheel 13 as a control object when determining that only one drive wheel 13 is grounded, controls to maintain the grounded state of the drive wheels 13 when determining that both drive wheels 13 are grounded, and automatically selects the drive wheel 13 taken as a control object when determining that no drive wheel 13 is grounded. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is suitable for use in transportation work, towing work, rescue activities, monitoring activities, and information gathering activities in areas where there are many elements that hinder driving such as rough terrain and disaster sites. The present invention relates to a mobile robot and its control method.

  Conventionally, as the above-described mobile robots, there are, for example, a vehicle body and a robot equipped with a plurality of articulated leg wheels having a base end rotatably supported by the vehicle body and wheels at the distal end. There are mobile robots having a configuration in which a pivot leg is rotatably supported at the tip of a joint leg wheel, and wheels are arranged at both ends of the pivot leg. In either case, the vehicle moves at high speed using the wheels, while on the rough terrain, it makes use of each articulated leg wheel to walk, for example, to overcome a high level difference (see, for example, Patent Document 1). .

In such a mobile robot that attempts to achieve both running and obstacle traversal, a moving robot equipped with a multi-joint leg wheel having a wheel at the tip is set in advance with a trajectory of the wheel and passes through the trajectory. In such a way, the trajectory for moving the wheel is automatically generated by a method for controlling the position and a grounding sensor or a distance meter disposed at the tip of the articulated leg wheel, and the position is controlled so as to pass through the obtained trajectory. The method is adopted.
JP 4-101791 A

  However, in the above-described conventional mobile robot, in the case of a mobile robot in which wheels are arranged at both ends of the swivel leg portion at the tip of the articulated leg wheel, one of the two wheels or both of the wheels are arranged. Since there is a case where the wheels are in contact with the ground, it is not possible to specify one wheel for position control. At this time, even if it is possible to specify one wheel for position control, for example, a mobile robot If the pilot of the user operates a wheel other than the specific wheel as a control target, the mobile robot may perform a leg motion different from the intention of the pilot.

  Therefore, in order to cope with this, a method for allowing the operator to select a wheel specified for position control as a wheel to be controlled, or a wheel at a low position based on position coordinates of the articulated leg wheel is specified for position control. However, in the former case, it takes time to select the wheel, and in addition, the wheel to be controlled must be selected every time the operator performs the leg operation. On the other hand, in the latter case, for example, if a wheel at a high position is in contact with a step or the like, the wheel at this high position must be controlled. However, there is a problem that there is a possibility of erroneous movement, and solving these problems has been a conventional problem.

  The present invention has been made paying attention to the above-described conventional problems, and performs grounding control of the wheels located at both ends of the swivel leg portions arranged at the tips of the articulated leg wheels by a simple operation safely and quickly. In addition, it is possible to automatically select a wheel to be grounded, and to provide a mobile robot that can realize automation of control of articulated leg wheels and a control method thereof .

  The invention according to claim 1 of the present invention includes a vehicle body, a rotating leg portion whose base end portion can be rotated about a horizontal axis and can be fixed at an appropriate position with respect to the vehicle body, and an appropriate position. Drive wheels that rotate forward and backward in a fixed manner are disposed at both ends, and a central portion is supported so as to be rotatable about a horizontal axis with respect to the distal end portion of the rotating leg and fixed at an appropriate position. An articulated leg wheel having a swivel leg that swivels about a horizontal axis with respect to the vehicle body by rotation of the swivel leg, and drive wheels located at both ends of the swivel leg of the articulated leg wheel A driving wheel grounding state detection unit that determines whether or not the vehicle is grounded, wherein the driving wheel grounding state detection unit determines that only one of the driving wheels of the articulated leg wheel is grounded. Then, this grounded drive wheel is controlled and the one-wheel grounding mode is controlled. In addition, when it is determined that both driving wheels are grounded, control is performed in the two-wheel grounding mode in order to maintain the grounding state of these driving wheels, and both driving wheels are grounded. It is characterized by having a configuration in which a control unit that automatically selects a drive wheel to be controlled by control in the no-ground mode is provided at the stage where it is determined that the mobile robot has this configuration. It is a means to solve the problem.

  In the mobile robot according to claim 2 of the present invention, in the no-ground mode, the control unit moves the driving leg of the articulated leg wheel and sets the swing leg to the tip of the rotating leg. When a rotation direction command is given, a drive wheel that moves in the direction of the movement command is determined by the rotation of the swivel leg according to the command, and the drive wheel is set as a drive wheel to be controlled. It is configured.

Furthermore, in the case of the mobile robot according to claim 3 of the present invention, in the no-ground mode, the control unit is based on the positional relationship between the two driving wheels in the articulated leg wheel and the center of gravity of the vehicle body or the ground. The driving wheel whose posture is stable is set as the driving wheel to be controlled.
On the other hand, the invention according to claim 4 of the present invention is provided with a vehicle body, and a rotating leg supported with respect to the vehicle body so that a base end portion can rotate about a horizontal axis and can be fixed at an appropriate position. And a driving wheel that rotates forward and backward so as to be fixed at an appropriate position is disposed at both end portions, and a central portion is rotatable about a horizontal axis with respect to a distal end portion of the rotating leg portion and at an appropriate position. A control method for a mobile robot including articulated leg wheels that are supported so as to be fixed and that have turning legs that turn around a horizontal axis with respect to the vehicle body by turning the turning legs. When it is recognized that only one of the articulated leg wheels is in contact with the ground, the grounded driving wheel is controlled as a control object and the one-wheel contact mode is controlled. At the stage of recognizing that they are touching the ground, In order to maintain the ground condition, control is performed in the two-wheel contact mode, and when it is recognized that neither drive wheel is grounded, the drive wheel to be controlled is automatically selected by the control in the no-ground mode. It is configured to do.

  In the mobile robot control method according to claim 5 of the present invention, in the no-ground mode, the drive wheel movement command in the articulated leg wheel and the rotation direction of the swivel leg with respect to the tip of the rotating leg In response to this command, the swivel leg is rotated in accordance with the command, the driving wheel moving in the direction of the movement command is determined by the rotation of the swivel leg, and the driving wheel is controlled. It is set as a drive wheel.

Furthermore, the mobile robot control method according to claim 6 of the present invention measures the positional relationship between the two drive wheels in the articulated leg wheel and the center of gravity of the vehicle body or the ground in the no-grounding mode. The driving wheel whose posture is stabilized is determined from the measurement result, and the driving wheel is set as the driving wheel to be controlled.
In the mobile robot and its control method according to the present invention, at the stage where it is recognized that both of the two driving wheels in the articulated leg wheels are in contact with the ground, the two-wheel grounding mode is used to maintain the grounding state of these driving wheels. However, as a method of maintaining the grounding state of the two drive wheels, in the leg drive source (joint of the swivel leg) located at the connecting portion between the swivel leg and the swivel leg. A method of driving the swing leg so that the same drive current and load are applied to the drive wheels located at both ends of the current value, load, or both ends of the swing leg, or two drive wheels and the ground using a laser distance measuring device To calculate the position where both wheels touch the ground, or to turn off the leg drive source of the swivel leg or release the clutch mechanism attached to the leg drive source to make it free , Passively move the swivel leg It can be employed to method.

  In addition, as described above, when attempting control in the two-wheel contact mode, the result of calculating the operation command (position, speed, torque command) to the leg drive source of the swivel leg and the drive wheel is as follows. If it is determined that the wheel cannot be grounded, measure the distance between the two drive wheels and the center of gravity of the vehicle body, and use the wheel with the longer distance from the center of gravity where the posture is stable as the wheel to be controlled. Shifts to control of 1-wheel contact mode.

Since the mobile robot according to claim 1 and the mobile robot control method according to claim 4 of the present invention have the above-described configuration, the positions of the wheels positioned at both ends of the swivel leg portion disposed at the tip of the articulated leg wheel. A very excellent effect is obtained that the control can be performed safely and quickly with a simple operation.
In addition, since the mobile robot according to claims 2 and 3 of the present invention and the mobile robot control method according to claims 5 and 6 are configured as described above, the wheel to be grounded is automatically selected in the wheel position control. As a result, it is possible to achieve an excellent effect that it is possible to realize automation of the control of the articulated leg wheels.

Hereinafter, a mobile robot according to the present invention will be described with reference to the drawings.
1 to 5 show an embodiment of a mobile robot according to the present invention.
As shown in FIG. 1, the mobile robot 1 includes a vehicle body 2 and articulated leg wheels 10 disposed at a total of four locations, front, rear, left, and right of the vehicle body 2.
The articulated leg wheels 10 arranged at a total of four positions in the front, rear, left and right of the vehicle body 2 are pivotable legs whose base end portions 11a are supported so as to be rotatable about the horizontal axis with respect to the vehicle body 2 and fixed at appropriate positions. A drive wheel 13 integrally having a portion 11, a wheel body 13 a and a drive motor 13 b for rotating the wheel body 13 a forward and backward is disposed at both end portions 20 a and 20 a, and a central portion 20 b is the tip of the rotating leg portion 11. A swiveling leg portion 20 that is turnable about a horizontal axis with respect to the portion 11b and is supported so as to be fixed at an appropriate position and that turns around the horizontal axis with respect to the vehicle body 2 by turning of the turning leg portion 11 is provided. is doing.

  The rotating leg portion 11 of the articulated leg wheel 10 is rotated by the output from the motor 12 disposed in the vehicle body 2, while the swiveling leg portion 20 of the articulated leg wheel 10 is The two drive wheels 13 supported by the swing leg 20 are rotated by the output from the motor 14 disposed in the center 20b. The grounding state of the two drive wheels 13 is connected to the center 20b of the swing leg 20. The ground contact detection sensor (driving wheel ground contact state detection means) 15 is used for determination.

  At this time, the grounding detection sensor 15 is a sensor of a type that recognizes the grounding state by measuring the load torque from the current values of the motors 12 and 14 generated when the driving wheel 13 or the turning leg 20 is operated, A sensor for measuring the load applied to the driving wheel 13 or the turning leg 20 can be used, and as will be described later, it is used for measuring the outside world installed on the upper part of the vehicle body 2 (or on the rotating leg 11). The ground range may be recognized by measuring the distance between the ground and the drive wheel 13 by the laser range finder 8.

In addition, the mobile robot 1 is configured such that the turning leg 11, the turning leg 20, and the driving wheel 13 are in accordance with a movement command for the driving wheel 13 and a command for the rotation direction of the turning leg 20 with respect to the tip of the turning leg 11. A motor control unit (control unit) 4 that calculates and transmits command values (position command value, speed command value, torque command value) to each of the motors 12, 13b, 14 that drive the vehicle is mounted on the vehicle body 2.
A control device 3 that creates and transmits an operation command to the mobile robot 1, a communication unit 5 that receives a command from the control device 3 and transmits the command to the motor control unit 4, and a laser for measuring the outside world A configuration including a range finder 8 may be used, and the control device 3 that transmits a command to the mobile robot 1 uses the one shown in FIG. 2A as an example, or FIG. 2B as another example. Can be used.

  In the control device 3A shown in FIG. 2A, a command value for moving the tip of the articulated leg wheel 10 is input by moving a joystick 32 installed in the control device main body 31 up, down, left and right. The rotation direction of the swivel leg 20 is input by moving the rocker switch 33 installed on the joystick 32 in either direction, while the portable control device 3B shown in FIG. 2 (b). Then, a command value for moving the tip of the articulated leg wheel 10 is input by moving the control device 3B itself up, down, left and right, and back and forth, and by tilting the control device 3B itself in a specific direction, The direction of rotation is entered.

At this time, the operation command for the mobile robot 1 can be generated by the motor control unit 4 itself judging from the surrounding situation instead of the control device 3.
Next, a procedure for controlling the position of the drive wheel 13 of the mobile robot 1 having such a configuration will be described.
First, the operator operates the control device 3 or the motor control unit 4 itself determines from the surrounding situation, and selects the articulated leg wheel 10 of the mobile robot 1 or a specific articulated leg wheel 10. And a control command for moving the drive wheel 13 to be controlled. This control command is composed of a position command value, a speed command value, a torque command value, a rotation direction command value of the swivel leg portion 20 and the like of the driving wheel 13 in the articulated leg wheel 10, and these command values are abstracted. It may be a simplified command.

On the vehicle body 2 side of the mobile robot 1, the motor control unit 4 detects the grounding of the drive wheels 13 of the articulated leg wheels 10 to which the motor control unit 4 is currently grounded in step S1, as shown in the flowchart of FIG. The determination is made by the sensor 15.
In step S2, if the motor control unit 4 determines that only one of the drive wheels 13 is grounded, the operation mode is set to the one-wheel grounding mode in step S3. If it is determined that the driving wheel 13 is grounded, the operation mode is set to the two-wheel grounding mode in step S4, and further, in step S2, the two driving wheels 13 of the articulated leg wheel 10 are both grounded. If it is determined that the mode is not switched, it is checked in step S5 whether or not the mode can be switched. If the switching is possible, the operation mode is set to the no-ground mode in step S6.

At this time, factors for determining whether or not the operation mode can be switched include that the control command from the operator is input for a certain period of time (0), and that the grounding state is not established for a certain period of time. it can.
In steps S3, S4, and S6, after setting the mode, as shown below, the motors 12, 13b that drive the turning leg 11, the turning leg 20, and the driving wheels 13 for each operation mode, The command value for 14 is calculated.

  That is, in the one-wheel contact mode, after calculating the position coordinate of the drive wheel 13 that is in contact with the ground at this point in step S7, the drive wheel 13 whose position coordinate is calculated in step S9 after step S8 is controlled. In step S10, the motor control unit 4 determines the operation command values (position command values, speed commands) to the motors 12, 13b, 14 based on the position coordinates of the drive wheels 13 to be controlled and the control commands. Value, torque command value) is calculated and transmitted to the motors 12, 13b, 14 in step S11.

  In the two-wheel contact mode, after calculating the position coordinates of the drive wheel 13 that is in contact with the ground at this point in step S7, the motor control unit 4 determines that the articulated leg wheel 10 is in step S12 after step S8. Based on the position coordinates of the joint of the swivel leg 20 and the control command, the operation command values to the motors 12, 13b, 14 are held so that the two drive wheels 13 are both grounded. (Position command value, speed command value, torque command value) are calculated and transmitted to the motors 12, 13b, 14 in step S11.

  During this time, as a result of the calculation of the operation command values (position command value, speed command value, torque command value) to the motors 12, 13b, 14 in step S12, in step S13, both the two drive wheels 13 are not grounded. When it is determined that it is possible, for example, the distance between the two driving wheels 13 and the center of gravity of the vehicle body 2 is measured, and the driving wheel 13 having the longer distance from the center of gravity is set as the wheel to be controlled. As a driving wheel 13 to be controlled, the driving wheel 13 that is stable is shifted to the one-wheel ground contact mode.

On the other hand, in the no-ground mode, the motor control unit 4 calculates and transmits a command value for each of the motors 12, 13b, 14 according to the movement command in step S14.
At this time, in the motor control unit 4, a control command from the operator (position command value, speed command value, torque command value, rotation direction command value of the turning leg 20, etc. in the articulated leg wheel 10). Thus, the drive wheel 13 to be controlled is selected, and the command value to each of the motors 12, 13b, 14 corresponding to this is calculated and transmitted.

Here, FIG. 4 shows an example of the operator's operation under this situation.
As shown in FIG. 4, when a command for moving the drive wheel 13 in the vertical direction (straight arrow) and a command for the rotation direction of the swivel leg 20 (curved arrow) are given by the driver, the motor control unit 4 A drive wheel 13 that moves up and down in the command direction as the swivel leg 20 rotates in the direction of rotation according to a given command (the drive wheel 13 with hatching) is determined, and the drive wheel 13 is controlled. Set as a wheel.

At this time, when the command from the operator is abstracted and the rotation direction of the swivel leg 20 is unknown, or when the control command is created by the motor control unit 4, the motor control unit 4 The distance between the two driving wheels 13 and the center of gravity of the vehicle body 2 is measured, and the driving wheel 13 having the longer distance from the center of gravity where the posture is stable is set as the wheel to be controlled.
Next, the operation of the mobile robot 1 will be described.

  FIG. 5A shows an operation when the turning leg 20 is moved downward with respect to the vehicle body 2 from the state where the two drive wheels 13 are in contact with the ground. Since the grounding detection sensor 15 recognizes the grounding of the two drive wheels 13, it moves in the two-wheeled grounding mode, but it is determined that the joint position of the swivel leg 20 cannot be extended any more in the two-wheeled grounding state. This is an example of switching to the one-wheel contact mode.

FIG. 5B shows an operation when the swing leg 20 is moved upward with respect to the vehicle body 2 from a state where one drive wheel 13 is grounded. At first, since the ground detection sensor 15 recognizes the grounding of one drive wheel 13, it moves in the one-wheel grounding mode. However, it is determined that the two driving wheels 13 are grounded and switches to the two-wheel grounding mode. This is an example.
FIG. 5C is an example in which the driving wheel 13 to be grounded is replaced with another driving wheel 13 when the swing leg 20 is moved upward with respect to the vehicle body 2.

Thus, in the mobile robot 1 according to this embodiment, the position control of the drive wheel 13 in the articulated leg wheel 10 can be performed smoothly in any situation.
In the mobile robot 1 according to the above-described embodiment, the articulated leg wheels 10 are arranged at all four positions on the front and rear, left and right of the vehicle body 2, but the present invention is not limited to this, and as shown in FIG. The articulated leg wheels 10 are arranged at two positions on the left and right of the front part (or rear part) of the vehicle body 2, and around the horizontal axis with respect to the vehicle body 2 at two right and left parts of the rear part (or front part) of the vehicle body 2. A rotating leg 41 supported so as to be able to rotate and to be fixed at an appropriate position, and a driving wheel 13 that is disposed at the tip of the rotating leg 41 and rotates in the forward and reverse directions are provided. A single joint leg wheel 40 may be arranged, or the leg wheel 40 may be arranged at one central portion of the rear part (or front part) of the vehicle body 2.

In the mobile robot 1 according to the above-described embodiment, the driving wheel 13 integrally includes the wheel main body 13a and the driving mechanism 13b that rotates the wheel main body 13a in the forward and reverse directions. However, the present invention is not limited thereto. Instead, the wheel main body 13a and the drive mechanism 13b may be separate.
Furthermore, in the mobile robot 1 according to the above-described embodiment, the case where the drive wheels 13 and 13 disposed at both end portions 20a and 20a of the swivel leg portion 20 of the articulated leg wheel 10 are the same size is shown. However, the present invention is not limited to this, and the diameters of the drive wheels 13 and 13 of the turning leg 20 may be different from each other.

It is side explanatory drawing of the driving | running | working state which shows simply one Embodiment of the mobile robot which concerns on this invention. FIG. 2 is an explanatory perspective view (a) showing one configuration example of the control device of the mobile robot in FIG. 1 and an explanatory perspective view (b) showing another configuration example of the control device. It is a flowchart explaining the control method of the mobile robot shown in FIG. FIG. 3 is a behavior explanatory diagram of driving wheels by an operation of a driver in a no-grounding mode of the mobile robot shown in FIG. 1. It is operation | movement explanatory drawing (a)-(c) of the mobile robot shown in FIG. It is side explanatory drawing of the driving | running | working state which shows other embodiment of the mobile robot which concerns on this invention simply.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mobile robot 2 Car body 4 Motor control part (control part)
DESCRIPTION OF SYMBOLS 10 Articulated leg wheel 11 Turning leg part 13 Drive wheel 15 Grounding detection sensor (Drive wheel grounding state detection means)
20 slewing leg 20a both ends of slewing leg 20b central part of slewing leg

Claims (6)

The car body,
Rotating legs that are supported so that the base end can rotate about the horizontal axis and can be fixed at an appropriate position with respect to the vehicle body, and driving wheels that rotate forward and backward to be fixed at an appropriate position are arranged at both ends. And a central portion is supported so as to be rotatable about a horizontal axis with respect to a tip portion of the rotating leg portion and fixed at an appropriate position. An articulated leg wheel having a swivel leg that swivels around a horizontal axis;
Drive wheel grounding state detection means for determining whether or not the drive wheels located at both ends of the swivel leg of the articulated leg wheel are grounded,
When the driving wheel grounding state detecting means determines that only one of the articulated leg wheels is grounded, the grounding driving wheel is controlled as a control object in the one-wheel grounding mode. In addition, when it is determined that both driving wheels are grounded, control is performed in the two-wheel grounding mode in order to maintain the grounding state of these driving wheels, and both driving wheels are grounded. A mobile robot comprising a control unit that automatically selects a drive wheel to be controlled by control in a no-ground mode when it is determined that the vehicle is not in contact.   In the no-grounding mode, the control unit complies with this command when a command for moving the driving wheel in the articulated leg wheel and a command for the direction of rotation of the swivel leg with respect to the tip of the rotating leg are given. The mobile robot according to claim 1, wherein a drive wheel that moves in the direction of the movement command is determined by a rotation operation of the turning leg portion, and the drive wheel is set as a drive wheel to be controlled.   In the no-grounding mode, the control unit determines the driving wheel whose posture is stabilized based on the positional relationship between the two driving wheels in the articulated leg wheel and the center of gravity of the vehicle body or the ground as the driving wheel to be controlled. The mobile robot according to claim 1, set as: A vehicle body is provided, and a base end portion is rotatable about a horizontal axis with respect to the vehicle body and is supported so as to be fixed at an appropriate position. Drive wheels are arranged at both end portions, and a central portion is supported so as to be rotatable about a horizontal axis with respect to a tip portion of the rotating leg portion and fixed at an appropriate position. A method for controlling a mobile robot provided with articulated leg wheels provided with turning legs that turn around a horizontal axis with respect to the vehicle body by turning,
When it is recognized that only one of the articulated leg wheels is grounded, the grounded driving wheel is controlled as a control object in the one-wheel grounding mode, and both of the driving wheels are In order to maintain the grounding state of these driving wheels, control is performed in the two-wheel grounding mode, and no grounding occurs when both driving wheels are recognized as not grounding. A method for controlling a mobile robot, wherein a driving wheel to be controlled is automatically selected by mode control.   In the no-ground mode, when a command for moving the driving wheel in the articulated leg wheel and a command for the direction of rotation of the swivel leg with respect to the tip of the swivel leg are given, the swivel leg is moved according to this command. The mobile robot control method according to claim 4, wherein a drive wheel that is rotated and moves in the direction of the movement command by the rotation operation of the swivel leg is determined, and the drive wheel is set as a drive wheel to be controlled.   In the no-ground mode, the positional relationship between the two driving wheels in the articulated leg wheel and the center of gravity or the ground of the vehicle body is measured, and the driving wheel whose posture is stable is determined from this measurement result, The method for controlling a mobile robot according to claim 4, wherein the driving wheel is set as a driving wheel to be controlled.

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