Robot system and method for controlling the robot system

Abstract

To reduce the burden on the operator when receiving reaction forces from the object. [Solution] A robot system comprising a master robot equipped with a master arm and a slave robot equipped with a slave arm, wherein in a maintenance mode in which the slave arm maintains the pressing force that is generated when the master arm is pushed, the slave arm maintains the pressing force but does not feed back the value of the reaction force from the object to the master robot. Therefore, the operator does not need to operate the master arm to maintain a force that counteracts the reaction force, and the burden on the operator when receiving a reaction force from the object can be reduced.

Description

Technical Field

[0001] The technology of the present disclosure relates to a robot system and a method for controlling the robot system.

Background Art

[0002] There is a master-slave manipulator for a method of performing work by bringing the end effector of a robot into contact with a work object by remote operation. The master-slave manipulator is composed of a master arm operated by an operator and a slave arm that moves following the master arm. As a method for controlling these, bilateral control is widely used. In bilateral control, by causing the master arm to generate the reaction force received by the slave arm from the work object, the operator can obtain an operation feeling as if the master arm is in contact with the work object, and the operability of the work by remote operation is improved.

[0003] Related technology is disclosed in Patent Document 1. Patent Document 1 discloses a contact mode that is performed when the slave arm is in contact with a work object. In this contact mode, with respect to the direction of the force, the slave arm is force-controlled with a preset force target value, and the same force as the reaction force applied to the slave arm is generated in the master arm.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the prior art, the reaction force received by the slave arm from the work object is transmitted to the master arm, and the operator needs to work so as to always maintain a force opposing this reaction force on the master arm. Therefore, the burden on the operator is large.

[0006] The technology disclosed herein aims to provide a robot system and a control method for the robot system that can reduce the burden on the operator when receiving a reaction force from an object. [Means for solving the problem]

[0007] To achieve the above objective, a first aspect of the technology of this disclosure is a robot system comprising a master robot having a master arm and a slave robot having a slave arm, wherein in a maintenance mode in which the slave arm maintains a pressing force that is generated when the master arm is pushed, the slave arm maintains the pressing force but does not feed back the value of the reaction force from the object to the master robot.

[0008] A second aspect is a control method for a robot system comprising a master robot having a master arm and a slave robot having a slave arm, wherein in a maintenance mode in which the slave arm maintains the pressing force that is generated when the master arm is pushed, the slave arm maintains the pressing force but does not feed back the value of the reaction force from the object to the master robot. [Effects of the Invention]

[0009] In the technology disclosed herein, in a maintenance mode in which the slave arm maintains the pressing force that the master arm generates when the master arm is pushed, the slave arm maintains the pressing force but does not feed back the value of the reaction force from the object to the master robot. Therefore, the operator does not need to operate the master arm to maintain a force that counteracts the reaction force, and the burden on the operator when receiving a reaction force from the object can be reduced. [Brief explanation of the drawing]

[0010] [Figure 1]Figure 1 is a block diagram of an example of a robot system 100. [Figure 2] Figure 2 shows an example of the postures of the master robot arm 10 and the slave robot arm 20 when the slave robot arm 20 is remotely controlled by an operator operating the master robot arm 10. [Figure 3] Figure 3 is a block diagram of an example of the electrical system of the slave robot 2040. [Figure 4] Figure 4 shows an example of a timing chart for the robot system 100 of this embodiment. [Figure 5] Figure 5 shows an example of how the bilateral control mode [A] and assist mode [C] of the robot system 100 of this embodiment are repeated. [Figure 6] Figure 6 shows an example of how the operator moves the master robot arm 10 in the Z direction when in assist mode [C]. [Figure 7] Figure 7 shows an example of how the operator controls the master robot arm 10 to move in the X and Y directions perpendicular to the Z direction in assist mode [C]. [Modes for carrying out the invention]

[0011] [Embodiment] Embodiments of the technology of this disclosure will be described below with reference to the drawings.

[0012] [Embodiment] (composition) The configuration of the robot system 100 of this embodiment will now be described. Figure 1 is a block diagram of an example of the robot system 100. As shown in Figure 1, the robot system 100 comprises a master robot 1030 and a slave robot 2040 whose posture changes according to a command value determined in accordance with the posture change of the master robot 1030. The master robot 1030 comprises a master robot arm 10 and a master robot controller 30. The slave robot 2040 comprises a slave robot arm 20 and a slave robot controller 40.

[0013] When remotely controlling the slave robot 2040, the operator controls the master robot arm 10, and the master robot controller 30 transmits the angle and torque information of the master robot arm 10 at that time as command values ​​to the slave robot controller 40 via wireless or wired communication. The slave robot controller 40 then controls the slave robot arm 20 so that its posture changes according to the received command values. As a result, the slave robot arm 20 acts on the target object. The robot system 100 of this embodiment may have a flat or curved surface. It is also applicable to remotely operated robots that perform tasks by following the surface of an object while applying a constant force to the object. For example, polishing or grinding robots (i.e., industrial robots) or cleaning robots for desks, etc.

[0014] In this embodiment of the robot system 100, the master robot controller 30 and the slave robot controller 40 communicate bidirectionally with each other. As a result, the slave robot controller 40 transmits information on the angle and torque of the slave robot to the master robot controller 30 via wireless or wired communication. The master robot controller 30 controls the master robot arm 10 so that its posture changes according to this information.

[0015] FIG. 2 is a diagram showing an example of the postures of the master robot arm 10 and the slave robot arm 20 when the operator remotely operates the slave robot 2040 by operating the master robot arm 10. As shown in FIG. 2, the master robot arm 10 includes arm portions 10p1 to 10p6 connected by a plurality of joints J11 to J15. The slave robot arm 20 includes arm portions 20p1 to 20p6 connected by a plurality of joints J21 to J25.

[0016] The operator grasps the arm portion 10p6 at the tip of the master robot arm 10 and applies a predetermined force to the master robot arm 10. Thereby, the command value is transmitted to the slave robot controller 40, and the slave robot controller 40 controls the posture of the slave robot arm 20. Thereby, the arm portion 20p6 at the tip of the slave robot arm 20 applies a force to the object to be contacted. When a force is applied from the arm portion 20p6 to the object, the object applies a reaction force to the arm portion 20p6.

[0017] A switch 10SW for instructing a transition to an assist mode described later is provided on the arm portion 10p5 of the master robot arm 10.

[0018] In the present embodiment, the arm portion 10p1 on the proximal end side of the master robot arm 10 is fixed to a fixing body 10K fixed to the floor. The arm portion 20p1 on the proximal end side of the slave robot arm 20 is fixed to a fixing body 20K fixed to the floor.

[0019] FIG. 3 is a block diagram of an example of the electrical system of the slave robot 2040. As shown in FIG. 3, each of the joints J21 to J25 of the slave robot arm 20 includes a motor 22, an encoder 24, and a torque sensor 26.

[0020] The slave robot controller 40 comprises a computer 50, a display device 62, and a communication device 64. The computer 50 includes a processor 52, an NVM (Non-volatile memory) 54, a RAM (Random Access Memory) 56, and an input / output (I / O) port 58. The processor 52, NVM 54, RAM 56, and input / output (I / O) port 58 are interconnected by a bus 60. The input / output (I / O) port 58 is connected to each joint J21 to J25 of the slave robot arm 20, to a motor 22, an encoder 24, and a torque sensor 26, as well as to the display device 62 and the communication device 64.

[0021] The processor 52 is a processing unit that includes a DSP (Digital Signal Processor), a CPU (Central Processing Unit), and a GPU (Graphics Processing Unit). The DSP and GPU operate under the control of the CPU and are responsible for executing the processes described later. Here, a processing unit including a DSP, CPU, and GPU is given as an example of the processor 52, but this is only an example, and the processor 32 may be one or more CPUs and DSPs with integrated GPU functionality, or one or more CPUs and DSPs without integrated GPU functionality, or it may be equipped with a TPU (Tensor Processing Unit).

[0022] NVM54 is a non-volatile memory device that stores programs and various parameters. Examples of NVM54 include flash memory (e.g., EEPROM (Electrically Erasable and Programmable Read Only Memory)). The attitude control program 54P is stored in NVM54.

[0023] RAM56 is memory that temporarily stores information and is used as work memory by the processor 52. Examples of RAM56 include DRAM (Dynamic Random Access Memory) or SRAM (Static Random Access Memory).

[0024] The electrical system of the master robot 1030 is almost identical to that of the slave robot 2040, except that switch 10SW (see Figure 2) is connected to input / output (I / O) port 58.

[0025] (action) Next, the operation of this embodiment will be explained.

[0026] Figure 4 is an example of a timing chart for the robot system 100 of this embodiment. Figure 5 is a diagram showing an example of the repetition of the bilateral control mode [A] and assist mode [C] of the robot system 100 of this embodiment. Figure 6 is a diagram showing an example of the operation in assist mode [C] where the operator moves the master robot arm 10 in the Z direction. Figure 7 is a diagram showing an example of the operation in assist mode [C] where the operator moves the master robot arm 10 in the X and Y directions perpendicular to the Z direction.

[0027] The processors 52 of the master robot controller 30 and the slave robot controller 40 each execute their respective attitude control programs 54P. This executes the control method for the robot system.

[0028] For example, as shown in Figure 5, when the arm portion 20p6 of the slave robot arm 20 is not in contact with the object 55, the robot system 100 is in normal mode, i.e., bilateral control mode [A].

[0029] [Bilateral control mode (A)] The bilateral control mode [A] is described below.

[0030] In step 51, operator 5 operates the arm portion 10p6 of the master robot arm 10 in order to remotely control the slave robot 2040.

[0031] In step 102, the master robot controller 30 detects the position and torque of the master robot arm 10 at that time, and in step 104, transmits the position and torque information as command values ​​to the slave robot controller 40 via wireless or wired communication.

[0032] In step 202, the slave robot controller 40 receives a command value, and in step 204, controls the slave robot arm 20 so that its posture changes according to the received command value.

[0033] In bilateral control mode [A], the above process is performed each time operator 5 operates the arm portion 10p6 of the master robot arm 10.

[0034] On the other hand, as a result of operator 5 operating the arm portion 10p6 of the master robot arm 10, the arm portion 20p6 of the slave robot arm 20 may come into contact with the object 55.

[0035] In this case, when a force is applied to the arm portion 20p6, the object 55 acts a reaction force on the arm portion 20p6.

[0036] In step 206, the slave robot controller 40 detects the reaction force from the value of the torque sensor 26, and in step 208, it transmits the detected reaction force value to the master robot controller 30.

[0037] In step 106, the master robot controller 30 receives the value of the reaction force, and in step 107, it changes the posture of the master robot arm 10 so that the reaction force is applied.

[0038] As a result, in step 54, operator 5 senses the reaction force and operates the master robot arm 10 to apply a force to the arm portion 10p6 that counteracts the reaction force.

[0039] However, if the operator 5 has to constantly apply a force to the arm portion 10p6 of the master robot arm 10 to counteract the above reaction force, the operator 5 will become fatigued and bear a heavy burden.

[0040] Therefore, in this embodiment, an assist mode [C] is provided to reduce the burden on the operator 5.

[0041] [Switching from bilateral control mode (A) to assist mode (C)]

[0042] In this embodiment, to switch the robot system 100 from bilateral control mode [A] to assist mode [C], the operator 5 turns on switch 10SW in step 56 ([B]).

[0043] Furthermore, the system is not limited to turning on switch 10SW, but may also be configured to automatically switch from bilateral control mode [A] to assist mode [C] when: firstly, the master robot arm 10 performs a predetermined action; secondly, a predetermined voice is emitted by the operator 5; thirdly, the operator 5 performs a predetermined gesture; or fourthly, a pressing force exceeding a predetermined value is applied.

[0044] In step 108, the master robot controller 30 detects that switch 10SW has been turned ON. This allows the master robot controller 30 to recognize that the robot system 100 has been switched from bilateral control mode [A] to assist mode [C]. Therefore, in step 110, the master robot controller 30 sends an instruction to the slave robot controller 40 to switch to assist mode [C].

[0045] The slave robot controller 40 receives the above transition instruction in step 210.

[0046] [Assist Mode (C)] Next, we will explain Assist Mode [C].

[0047] In step 112, the master robot controller 30 detects the Z-direction position Z0 of the master robot arm 10 when the switch 10SW is turned on from the value of the encoder 24, and in step 114, controls each motor 22 so that the Z-direction position of the master robot arm 10 is maintained at the detected position Z0.

[0048] In step 212, the slave robot controller 40 detects the position Z00 of the slave robot arm 20 in the Z direction when the switch 10SW is turned on, from the value of the encoder 24, and in step 214, controls each motor 22 so that the position of the slave robot arm 20 in the Z direction is maintained at the detected position Z00. As a result, when the slave robot arm 20 is switched to assist mode [C], it maintains the force instructed by the master robot 1030 (force control), does not detect the reaction force, and therefore does not feed back the value of the reaction force to the master robot controller 30. Note that "not providing feedback" can also be rephrased as prohibiting the slave from transmitting reaction force information to the master robot.

[0049] The master robot arm 10 maintains its position in the Z direction when switched to assist mode [C] (position control). Therefore, as shown in Figure 6, even if the master robot arm 10 is pushed in the +Z direction by the operator 5, the position of the master robot arm 10 in the Z direction does not change.

[0050] As described above, the master robot controller 30 does not receive a force equivalent to the reaction force received by the slave robot arm 20, so the operator does not need to constantly maintain a force to counteract the reaction force. Therefore, the burden on the operator is reduced.

[0051] In assist mode [C] of this embodiment, as shown in Figure 7, the master robot arm 10 can move freely in the X and Y directions.

[0052] When operator 5 operates the arm portion 10p6 of the master robot arm 10 in the X or Y direction in step 57, the master robot controller 30 detects the position and torque of the master robot arm 10 at that time in step 116, and transmits the position and torque information as command values ​​to the slave robot controller 40 in step 118.

[0053] In step 216, the slave robot controller 40 receives a command value, and in step 218, controls the slave robot arm 20 so that its posture changes according to the received command value.

[0054] Figure 7 shows an example in which operator 5 moves the master robot arm 10 in the +X direction, and the slave robot arm 20 moves in the +X direction to follow it.

[0055] As described above, in assist mode [C] of this embodiment, the positions of the master robot arm 10 and the slave robot arm 20 in the Z direction are maintained at the detected positions Z0 and Z00. However, the master robot arm 10 and the slave robot arm 20 can move in the X and Y directions. Therefore, the operator 5 will have the sensation that there is a virtual wall VWz in the X and Y directions at the Z direction position when the assist mode is switched on. As a result, the master robot arm 10 will have the sensation of being attracted to the surface of a virtual object that has the same shape as the object 55 that the slave robot arm 20 is in contact with.

[0056] In assist mode [C], if the position of the slave robot arm 20 in the Z direction is maintained at position Z00 and the value of the reaction force is not fed back to the master robot controller 30, the master robot arm 10 may be made movable in the +Z direction.

[0057] [Disable Assist Mode [C] [D]] Next, we will explain how to deactivate assist mode [C] [D], that is, how to switch the robot system 100 from assist mode [C] to bilateral control mode [A].

[0058] In this embodiment, to switch from assist mode [C] to bilateral control mode [A], the arm portion 10p6 of the master robot arm 10 is pulled in the -Z direction. The operator 5 can switch control modes with an intuitive operation such as peeling off the object being held in place, and can perform the work without feeling any complexity even when frequent switching is required.

[0059] Furthermore, the system is not limited to pulling the arm portion 10p6 in the -Z direction. It may also be configured to switch from assist mode [C] to bilateral control mode [A] when it detects that a predetermined voice has been emitted by the operator 5 or that the operator 5 has performed a predetermined gesture.

[0060] In step 60, operator 5 pulls the arm 10p6 in the -Z direction to switch from assist mode [C] to bilateral control mode [A]. When the arm 10p6 is pulled in the -Z direction in this way, the master robot controller 30 detects in step 120 that the arm 10p6 is being pulled in the -Z direction and in step 122 sends an instruction to the slave robot controller 40 to deactivate assist mode [C].

[0061] In step 220, the slave robot controller 40 receives an instruction to deactivate assist mode [C] and recognizes that it has been switched to bilateral control mode [A].

[0062] As a result, the robot system 100 can be switched from assist mode [C] to bilateral control mode [A].

[0063] (effect) As described above, this embodiment includes an assist mode [C]. In assist mode [C], the master robot controller 30 does not receive a force equivalent to the reaction force received by the slave robot arm 20. Therefore, the operator does not need to maintain a force to counteract the reaction force. Thus, the burden on the operator is reduced.

[0064] In this embodiment, the operator does not need to maintain a force to counteract the reaction force, so they can concentrate on controlling movement in the X and Y directions.

[0065] In conventional bilateral control, the slave arm applies force to the object in proportion to the operation of the master arm. If there is a delay in communication between the master robot and the slave robot, the slave arm will push the object some time after the operator pushes the master arm. However, in the assist mode of this embodiment, the slave arm maintains the force instructed by the master robot when the assist mode is switched on, and the master arm maintains its position in the Z direction when the assist mode is switched on. Therefore, even if a communication delay occurs, the burden on the operator remains reduced.

[0066] [Note] (Note 1) A robot system comprising a master robot equipped with a master arm and a slave robot equipped with a slave arm, In the maintenance mode, which maintains the pressing force that the slave arm exerts on the object as a result of the master arm being pushed, the slave arm maintains the pressing force but does not feed back the value of the reaction force from the object to the master robot. Robot system.

[0067] (Note 2) In the maintenance mode, if the master arm moves in a direction perpendicular to the pressing direction, the slave arm follows the movement of the master arm. The robot system described in Appendix 1.

[0068] (Note 3) When the system switches to the aforementioned maintenance mode, the position of the master arm in the direction of the push is maintained at the position where the system switched to the maintenance mode. The robot system described in Appendix 1 or Appendix 2.

[0069] (Note 4) In the maintenance mode, even if the master arm moves in the pressing direction, the slave arm maintains the pressing force. The robot system described in Appendix 1 or Appendix 2.

[0070] (Note 5) If the master arm is pulled in the opposite direction to the direction in which it was pushed while the maintenance mode is active, the maintenance mode is released. A robot system described in any one of the following appendices, 1 to 3.

[0071] (Note 6) A control method for a robot system comprising a master robot equipped with a master arm and a slave robot equipped with a slave arm, In the maintenance mode, which maintains the pressing force that the slave arm exerts on the object as a result of the master arm being pushed, the slave arm maintains the pressing force but does not feed back the value of the reaction force from the object to the master robot. A method for controlling a robotic system. [Explanation of symbols]

[0072] 5 Operator 10 Master Robot Arm 10SW Switch 20 Slave Robot Arms 30 Master Robot Controllers 32 processors 40 Slave Robot Controllers 50 Computers 52 processors 55 Object 100 Robot Systems 1030 Master Robot 2040 Slave Robot

Claims

1. A robot system comprising a master robot equipped with a master arm and a slave robot equipped with a slave arm, In the maintenance mode, which maintains the pressing force that the slave arm exerts on the object as a result of the master arm being pushed, the slave arm maintains the pressing force but does not feed back the value of the reaction force from the object to the master robot. Robot system.

2. In the maintenance mode, if the master arm moves in a direction perpendicular to the pressing direction, the slave arm follows the movement of the master arm. The robot system according to claim 1.

3. When the system switches to the aforementioned maintenance mode, the position of the master arm in the direction of the push is maintained at the position where the system switched to the maintenance mode. The robot system according to claim 1.

4. In the maintenance mode, even if the master arm moves in the pressing direction, the slave arm maintains the pressing force. The robot system according to claim 1.

5. If the master arm is pulled in the opposite direction to the direction in which it was pushed while the maintenance mode is active, the maintenance mode is released. The robot system according to claim 1.

6. A control method for a robot system comprising a master robot equipped with a master arm and a slave robot equipped with a slave arm, In the maintenance mode, which maintains the pressing force that the slave arm exerts on the object as a result of the master arm being pushed, the slave arm maintains the pressing force but does not feed back the value of the reaction force from the object to the master robot. A method for controlling a robotic system.

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