JP2018149660A - robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for efficiently moving an object by suppressing slippage of a driving wheel when moving an object with an arm. SOLUTION: A robot 3 that horizontally pushes and moves a drawer 2 (movable object) supported so as to be horizontally movable and vertically immovable is a trolley 6 having a drive wheel 4 and a trolley 6. It is provided with an arm 7 supported by the arm 7, a hand 8 supported by the arm 7 and capable of gripping the drawer 2, and a control unit 9 for driving and controlling the drive wheel 4, the arm 7, and the hand 8. The control unit 9 causes the hand 8 to grip the drawer 2, and one or both of the force and the torque of the drawer 2 in a direction different from the movable direction of the drawer 2 and in the immovable direction of the drawer 2. Is driven and controlled so that the drawer 2 is moved horizontally while operating the above. [Selection diagram] Fig. 6

Description

  The present invention relates to a robot.

  Patent Document 1 discloses torque control of a robot that includes a carriage and an arm and carries an object with the arm.

JP 2010-188471 A

  However, in the configuration of Patent Document 1, depending on the arrangement of the driving wheels, when the object is moved by the arm, the vertical force of the driving wheel of the carriage is lowered by the reaction force that the arm receives from the object, and the object is efficiently moved. There was a case that could not be done.

  An object of the present invention is to provide a technique for efficiently moving an object by suppressing slippage of a drive wheel when the object is moved by an arm.

  According to an embodiment of the present invention, a robot that moves horizontally by pushing a moving object that is supported so as to be horizontally movable but not vertically movable, and has at least one drive wheel. And an arm supported by the carriage, a hand supported by the arm and capable of gripping the moving object, and a control unit that drives and controls the drive wheel, the arm, and the hand. The unit causes the hand to grip the moving object and applies force and torque to the moving object in a direction different from a direction in which the moving object can move and in a direction in which the moving object cannot move. A robot is provided that controls the drive so that the moving object moves horizontally while acting either one or both of them.

  ADVANTAGE OF THE INVENTION According to this invention, when moving an object with an arm, the slip of a drive wheel can be suppressed and an object can be moved efficiently.

It is a figure which shows the robot in execution of the task which pushes drawer | drawer out into the bag. It is a figure which is performing the task which pushes drawer | drawing-out into a cage | basket, Comprising: The robot which is pushing in drawer | drawer, pushing up drawer | drawer. It is a figure which is performing the task which pushes drawer | drawing-out into a cage | basket, Comprising: The robot which is pushing in drawer | drawer, pushing down drawer | drawer. It is a functional block diagram of a robot. It is a calculation flow of an operation plan. It is a figure for demonstrating the force which acts on a robot. It is a figure which shows the output torque of each motor.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a robot 3 that is executing a task of pushing in (pushing and moving) a drawer 2 (moving object) of the basket 1. The drawer 2 is supported by the eaves 1 so that it can move in the horizontal direction but cannot move in the vertical direction. Further, when the drawer 2 is pushed into the basket 1, friction is generated between the drawer 2 and the basket 1.

  As shown in FIG. 1, the robot 3 includes a cart 6 having a drive wheel 4 and a passive wheel 5, an arm 7 that can be tilted supported by the cart 6, and a hand that can grip the drawer 2 supported by the arm 7. 8, a drive wheel 4, an arm 7, and a control unit 9 that drives and controls the hand 8.

  As shown in FIG. 1, when the robot 3 moves toward the heel 1 while the hand 8 grips the drawer 2 pulled out from the heel 1, the drawer 2 is pushed into the heel 1 and accommodated in the heel 1. . At this time, the robot 3 applies a pushing force 11 necessary for pushing the drawer 2 to the drawer 2. And the robot 3 will receive the reaction force 12 of the said pushing force 11 in the hand 8, and the normal force of the wheel of the direction close | similar to the heel 1 will fall. Here, the hatched arrow is a force acting on the drawer 2, and the white arrow is a force acting on the robot 3.

(For front wheel drive)
If the driving wheel 4 is closer to the drawer 2 than the passive wheel 5 as shown in FIG. 1, the vertical drag of the driving wheel 4 is reduced and the road surface 10 becomes slippery and the above task may not be executed. .

  On the other hand, in this embodiment, as shown in FIG. 2, when the robot 3 moves toward the basket 1 with the hand 8 gripping the drawer 2 pulled out from the basket 1, the robot 3 A vertically upward push-up force 13 is applied to the drawer 2 via the hand 8 holding 2. As a result, the robot 3 receives the reaction force 14 of the push-up force 13 on the hand 8, and the vertical drag of the drive wheel 4 increases, so that it becomes difficult to slip on the road surface 10, and the above task is executed without any problem. become able to.

  Instead of the push-up force 13, the robot 3 may apply a push-down torque 15 that pushes down the tip 2 a to the drawer 2 via the hand 8 that holds the drawer 2. As a result, the robot 3 receives the reaction torque 16 of the push-down torque 15 on the hand 8, and the vertical drag of the drive wheels 4 increases.

(For rear wheel drive)
When the drive wheel 4 is farther from the drawer 2 than the passive wheel 5 as shown in FIG. 3, the robot 3 moves toward the cage 1 with the hand 8 gripping the drawer 2 drawn from the cage 1. At this time, the robot 3 applies a vertically downward pressing force 17 to the drawer 2 via the hand 8 holding the drawer 2. As a result, the robot 3 receives the reaction force 18 of the push-down force 17 on the hand 8, and the vertical drag of the drive wheels 4 increases, making it difficult for the robot 3 to slide with respect to the road surface 10. become able to.

  Instead of the push-down force 17, the robot 3 may apply a push-up torque 19 that pushes the tip 2 a to the drawer 2 via the hand 8 that holds the drawer 2. As a result, the robot 3 receives the reaction torque 20 of the push-up torque 19 on the hand 8, and the vertical drag of the drive wheels 4 increases.

  Next, the configuration of the robot 3 will be described in more detail.

  As shown in FIG. 4, the control unit 9 includes a CPU 30 (Central Processing Unit) as a central processing unit, a read / write free RAM 31 (Random Access Memory), and a read-only ROM 32 (Read Only Memory). Yes. Then, the CPU 30 reads and executes the control program stored in the ROM 32, so that the control program causes hardware such as the CPU 30 to function as the operation plan calculation unit 33 and the operation control unit 34.

  The operation plan calculation unit 33 determines the torques of a plurality of motors when the drawer 2 is moved by pushing the drawer 2. The operation control unit 34 controls each motor based on the torques of the plurality of motors determined by the operation plan calculation unit 33. The plurality of motors are a drive wheel motor 35 for driving the drive wheels 4, a first arm drive motor 36 for driving the cart side joint of the arm 7, and a second arm for driving the joint of the arm 7 on the hand 8 side. A driving motor 37 and a grip driving motor 38 for driving the gripping operation of the hand 8. Hereinafter, the operation of the operation plan calculation unit 33 will be described in detail.

  FIG. 5 is a flowchart regarding the operation of the operation plan calculation unit 33. FIG. 6 shows the force received by the robot 3 when executing the task of pushing the drawer 2 into the basket 1 with white arrows. Specifically, in FIG. 6, the horizontal reaction force that the hand 8 receives from the drawer 2 is indicated by Fx (the direction away from the drawer 2 is positive), and the vertical reaction force that the hand 8 receives from the drawer 2. Is indicated by Fy (vertical upward is positive), and reaction torque received by the hand 8 from the drawer 2 is indicated by T (counterclockwise is positive). Further, it is assumed that the robot 3 employs rear wheel drive in which the drive wheel 4 is farther from the drawer 2 than the passive wheel 5. The weight of the robot 3 is denoted by Mg, the vertical drag of the drive wheel 4 is denoted by N1, the vertical drag of the passive wheel 5 is denoted by N2, the frictional force that the drive wheel 4 receives from the road surface is denoted by f1, and the passive wheel 5 The frictional force received from the road surface is indicated by f2. Further, the distance between the lines of action between the vertical drag N1 and the self-weight Mg is indicated by L1, the distance between the lines of action between the self-weight Mg and the vertical drag N2 is indicated by L2, and the distance between the lines of action between the vertical drag N2 and the reaction force Fy is indicated. The height of the line of action of the reaction force Fx is indicated by H1. FIG. 7 illustrates the output torque of each motor. Specifically, in FIG. 7, the output torque of the drive wheel motor 35 is indicated by τ1, the output torque of the first arm drive motor 36 is indicated by τ2, and the output torque of the second arm drive motor 37 is indicated by τ3. .

  As illustrated in FIG. 5, the motion plan calculation unit 33 first determines an operation force necessary to execute a task (S100). Specifically, the motion plan calculation unit 33 determines the operating force required to push the drawer 2 into the heel 1. The reaction force Fx in FIG. 6 corresponds to the required reaction force reaction force.

  Next, as illustrated in FIG. 5, the motion plan calculation unit 33 determines an allowable maximum value of the hand force (S110). Specifically, the motion plan calculation unit 33 determines the direction in which the hand is constrained and the maximum value of the force that can be output in the direction based on the operation target and the posture of the robot 3. Note that the acting force and torque to be applied to the operation target are limited to the direction in which the hand is restrained. Here, when the operation target is the drawer 2, not only the direction in which the drawer 2 is pushed or pulled, but a vertical acting force may be applied to the drawer 2, and any torque is applied to the drawer 2. May be allowed to act. However, when the drawer 2 is pulled out largely from the heel 1, since the support of the drawer 2 by the heel 1 becomes incomplete, it is preferable to set the allowable maximum value of the hand force low. When the operation target is a door and the task of opening the door is executed, a hand force cannot be applied in the direction in which the door knob rotates. The following equation (1) indicates the allowable maximum value and the allowable minimum value of the hand force.

  Next, as shown in FIG. 5, the motion plan calculation unit 33 calculates the hand force and each motor torque (S120). Specifically, the motion plan calculation unit 33 includes (a) a balance conditional expression represented by the following expressions (2) and (3), and (b) each drive wheel 4 and each passive wheel 5 represented by the following expression (4). (C) Conditional expression in which each drive wheel 4 and each passive wheel 5 shown in the following expression (5) do not slip, (d) Conditional expression of hand force shown in the above expression (1) (a )-(D), the hand force (= Fy, T) and the output torque of each motor are calculated.

  As a method for obtaining the output torque of each motor, if it is not necessary to optimize, a hand force satisfying the above (a) to (d) may be obtained heuristically and then obtained by Jacobian or the like. Alternatively, in addition to the above (a)-(d), the relationship between the hand force expressed by the following formula (6) and the output torque of each motor, and the output torque of each motor is maximum as shown by the following formula (7). Considering the conditional expression that is less than or equal to the output torque, the output torque of each motor is calculated by nonlinear programming or the like so that the square sum of the output torque of each motor is minimized as shown in the following expression (8). Also good.

In the above equation (2), since f1 and f2 are forces on the same line of action, they are collectively expressed as f (= f1, f2).
In the above equation (5), μ is a coefficient of static friction between each wheel and the road surface.
The above equation (6) is a conditional equation established by excluding the torque for the own weight compensation. Further, the above formula (6) is based on the relational expression F = Jτ using Jacobian J, which is established between the hand force (F = (Fx, Fy, T)) and the output torque τ of each motor. Is. Jx, Jy, and Jθ are Jacobian components in the respective directions.

(Operation example 1)
Hereinafter, calculation example 1 of calculation in which specific numerical values are applied to the calculation executed by the operation plan calculation unit 33 will be introduced. In this embodiment, the task of pushing the drawer 2 into the rod 1 is executed, and the robot 3 employs rear wheel drive. That is, in FIG. 6, the drive wheel 4 is farther from the drawer 2 than the passive wheel 5. Further, it is assumed that the hand 3 (reaction force Fy, reaction torque T) is zero and the robot 3 performs only the operation of pushing the drawer 2.

  In FIG. 6, L1 = 0.15 [m], L2 = 0.15 [m], L3 = 0.50 [m], H1 = 0.30 [m], Mg = 100 [N], μ = 0 .3, since the front wheel is the passive wheel 5, f2 = 0, and the required operating force (= reaction force Fx) is 25 [N]. In this case, N1 = 75 [N], N2 = 75 [N], and f1 = 25 [N], which does not satisfy the following formula (9) which is the first formula of the above formula (5), and at the time of task execution, It is considered that the drive wheel 4 slips on the road surface.

(Calculation example 2)
In the above calculation example 1, the hand 3 (reaction force Fy, reaction torque T) is set to zero, and the robot 3 performs only the operation of pushing the drawer 2. However, instead of this, in the calculation example 2, while the reaction torque T of the hand force is zero, the drawer 2 is pushed down vertically when the task is executed. In this case, for example, when the reaction force Fy = 5 [N], N1 = 83.34 [N], N2 = 11.67 [N], and f1 = 25 [N], which satisfies the above formula (9). Thus, the task can be executed without the drive wheel 4 slipping on the road surface.

  As described above, even when the driving wheel 4 slips only by its own weight, when the external force is operated, the arm 7 generates a force or torque other than the operation direction, thereby causing the robot 3 itself to move vertically downward due to the reaction. Therefore, the friction force of the drive wheel 4 can be secured, so that a large external force can be generated without the drive wheel 4 slipping.

  Finally, in order to optimize the output torque of each motor at the time of executing the task, the above expression (1) is used with the above expression (8) as an objective function so that the square sum of the output torque of each motor is minimized. (3) (4) (5) (7) (8) may be solved by nonlinear programming.

  As mentioned above, although embodiment of this invention was described, the said embodiment has the following characteristics.

  A robot 3 that moves the drawer 2 (movable object) supported so as to be horizontally movable but not vertically movable by horizontally pushing the drawer 2 (the moving object) includes a carriage 6 having driving wheels 4 and passive wheels 5, and a carriage 6 The arm 7 is supported by the arm 7 and can be tilted, the hand 8 is supported by the arm 7 and can grip the drawer 2, and the drive wheel 4, the arm 7, and the control unit 9 that drives and controls the hand 8. The control unit 9 causes the hand 8 to grip the drawer 2 and, when the driving wheel 4 is closer to the drawer 2 than the passive wheel 5, pushes the drawer 2 horizontally while applying a vertically upward force to the drawer 2. The drive is controlled so as to move. When the driving wheel 4 is farther from the drawer 2 than the passive wheel 5, the control unit 9 controls the driving so that the drawer 2 is pushed and moved horizontally while applying a vertically downward force to the drawer 2. According to the above configuration, when the driving wheel 4 is closer to the drawer 2 than the passive wheel 5, the vertical drag force against the road surface 10 of the driving wheel 4 is increased by applying a vertically upward force to the drawer 2. When the drawer 2 is pushed horizontally, the driving wheel 4 can be prevented from slipping. Similarly, when the driving wheel 4 is farther from the drawer 2 than the passive wheel 5, the vertical drag force on the road surface 10 of the driving wheel 4 is increased by applying a vertically downward force to the drawer 2, so that the drawer 2 is placed horizontally. It is possible to prevent the drive wheel 4 from slipping when being pushed to the right. Therefore, the drawer 2 can be moved efficiently.

  Further, the robot 3 for moving the drawer 2 (movable object) supported so as to be horizontally movable but not vertically movable by horizontally pushing it includes a carriage 6 having at least one drive wheel 4 and a carriage. 6, an arm 7 supported by 6, a hand 8 supported by the arm 7 and capable of gripping the drawer 2, and a control unit 9 that drives and controls the drive wheel 4, the arm 7, and the hand 8. The control unit 9 causes the hand 8 to grip the drawer 2 and applies either or both of force and torque to the drawer 2 in a direction different from the direction in which the drawer 2 can move and in the direction in which the drawer 2 cannot move. The drive control is performed so that the drawer 2 is moved horizontally while acting. That is, by controlling the drive so that the drawer 2 is pushed and moved horizontally while applying a vertically upward force to the drawer 2, the cart 6 can be pressed vertically downward, and the vertical applied to each drive wheel 4. The sum of drag can be increased. In this case, the vertical drag of some of the drive wheels 4 may be reduced, but as a result, the force for pushing the drawer 2 horizontally can be increased. This can be mentioned even when all the wheels are drive wheels 4.

  In the above-described embodiment, the arm 7 is supported by the carriage 6 so as to be tiltable. Instead, the arm 7 has a posture in which the longitudinal direction is substantially horizontal, such as a forklift. It may be configured to move up and down in the vertical direction while maintaining the above.

(Appendix)
A robot that moves horizontally by pushing a moving object supported so as to be horizontally movable but not vertically movable;
A carriage having a drive wheel and a passive wheel;
An arm supported by the carriage and tiltable;
A hand supported by the arm and capable of gripping the moving object;
A control unit that controls driving of the driving wheel, the arm, and the hand;
With
The controller is
While causing the hand to grip the moving object,
When the driving wheel is closer to the moving object than the passive wheel, the driving wheel is controlled to move by moving the moving object horizontally while applying a vertically upward force to the moving object.
When the driving wheel is farther from the moving object than the passive wheel, driving control is performed such that the moving object is pushed and moved horizontally while applying a vertically downward force to the moving object.
robot.

(Appendix)
A robot that moves horizontally by pushing a moving object supported so as to be horizontally movable but not vertically movable;
A carriage having a drive wheel and a passive wheel;
An arm supported by the carriage;
A hand supported by the arm and capable of gripping the moving object;
A control unit that controls driving of the driving wheel, the arm, and the hand;
With
The controller is
While causing the hand to grip the moving object,
When the driving wheel is closer to the moving object than the passive wheel, the driving wheel is controlled to move by moving the moving object horizontally while applying a vertically upward force to the moving object.
When the driving wheel is farther from the moving object than the passive wheel, driving control is performed such that the moving object is pushed and moved horizontally while applying a vertically downward force to the moving object.
robot.

DESCRIPTION OF SYMBOLS 1 2 Pullout 2a Tip 3 Robot 4 Drive wheel 5 Passive wheel 6 Carriage 7 Arm 8 Hand 9 Control part 10 Road surface 11 Pushing force 12 Reaction force 13 Push-up force 14 Reaction force 15 Push-down torque 16 Reaction torque 17 Push-down force 18 Reaction force 19 Push-up torque 20 Reaction torque 33 Operation plan calculation unit 34 Operation control unit 35 Drive wheel motor 36 First arm drive motor 37 Second arm drive motor 38 Gripping drive motor

Claims (1)

A robot that moves horizontally by pushing a moving object supported so as to be horizontally movable but not vertically movable;
A carriage having at least one drive wheel;
An arm supported by the carriage;
A hand supported by the arm and capable of gripping the moving object;
A control unit that controls driving of the driving wheel, the arm, and the hand;
With
The controller is
While causing the hand to grip the moving object,
While moving one or both of force and torque on the moving object in a direction different from the direction in which the moving object can move and in a direction in which the moving object cannot move, the moving object Drive control to move horizontally,
robot.

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