JP7604264B2 - Control device, robot and control method - Google Patents

Description

This disclosure relates to a control device and a robot.

Conventionally, there are robot arms that are mounted on a moving device. For example, Patent Document 1 discloses an industrial robot device that includes an articulated industrial robot and a moving device that moves the industrial robot. The moving device has a horizontal two-joint link mechanism made up of two links, and is fixed to an installation surface. The industrial robot is attached to the tip of the tip-side link.

Japanese Patent Application Publication No. 1-281891

In the industrial robot device of Patent Document 1, when the industrial robot operates, the center of gravity of the industrial robot fluctuates, and the moment that the industrial robot applies to the link of the moving device may fluctuate. For example, when the industrial robot grasps a workpiece, the load and moment that the industrial robot applies to the link of the moving device may fluctuate. Such fluctuations in load and moment may cause deformation such as bending in the links and joints of the moving device. The deformation of the links and joints fluctuates the position of the industrial robot, and this fluctuation in position causes the industrial robot to vibrate. This may reduce the accuracy of the work of the industrial robot.

The present disclosure aims to provide a control device and a robot that suppresses unintended fluctuations in the position of the base of a second robot arm supported by a first robot arm.

A control device according to one aspect of the present disclosure is a control device for a first robot arm having at least two links supporting a second robot arm and at least one joint connecting the at least two links to each other, comprising a first estimation unit that acquires a first operation command for causing the first robot arm to perform a first target operation, which is a target operation, and estimates the operation of the at least one joint when the first robot arm operates in accordance with the first operation command, and a second estimation unit that acquires a second operation command for causing the second robot arm to perform a second target operation, which is a target operation, and estimates the operation of the at least one joint when the second robot arm operates in accordance with the second operation command, and a connection portion between the second robot arm and the link. a second estimation unit that estimates a force that the link receives from the second robot arm; a third estimation unit that estimates a force that the link receives based on the movement of the at least one joint estimated by the first estimation unit and the force estimated by the second estimation unit; a fourth estimation unit that estimates at least one of the deformation amount of the link and the deformation amount of the at least one joint based on the force estimated by the third estimation unit; and a correction command unit that generates a correction command for the first movement command to compensate for the deformation amount so as to move the connection part according to the first target movement based on the deformation amount estimated by the fourth estimation unit, and issues the correction command to the first robot arm.

The technology disclosed herein makes it possible to suppress unintended fluctuations in the position of the base of the second robot arm supported by the first robot arm.

FIG. 1 is a side view showing an example of a configuration of a robot according to an embodiment; FIG. 1 is a side view showing a model of an example of a configuration of a robot according to an embodiment; FIG. 1 is a block diagram showing an example of a hardware configuration of a control device according to an embodiment. FIG. 1 is a block diagram showing an example of a functional configuration of a control device according to an embodiment; 1 is a flowchart showing an example of an operation of a control device according to an embodiment. FIG. 1 is a side view showing a model of a configuration of a robot according to a first modified example. FIG. 11 is a side view showing a model of a configuration of a robot according to a second modification example.

(Embodiment)
Hereinafter, the embodiments of the present disclosure will be described with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. In addition, among the components in the following embodiments, components that are not described in the independent claims showing the highest concept are described as optional components. In addition, each figure in the attached drawings is a schematic diagram and is not necessarily illustrated precisely. Furthermore, in each figure, substantially the same components are given the same reference numerals, and duplicated descriptions may be omitted or simplified. In addition, in this specification and claims, "apparatus" may mean not only one apparatus but also a system consisting of multiple apparatuses.

[Robot configuration]
The configuration of a robot 1 according to an embodiment will be described with reference to Fig. 1 and Fig. 2. Fig. 1 is a side view showing an example of the configuration of the robot 1 according to an embodiment. Fig. 2 is a side view showing a model of the example of the configuration of the robot 1 according to the embodiment.

The robot 1 according to the embodiment includes a first robot arm 100, a second robot arm 200, and a control device 300. The first robot arm 100 is fixed to a support surface S and supports the second robot arm 200. The first robot arm 100 has at least one joint and at least two links, and the second robot arm 200 has at least one joint and at least one link.

In this embodiment, the first robot arm 100 includes two joints JTA1 and JTA2, three links 101 to 103, and actuators MA1 and MA2 for the joints JTA1 and JTA2, but is not limited thereto. The second robot arm 200 includes six joints JTB1 to JTB6, seven links 201 to 207, and actuators MB1 to MB6 for the joints JTB1 to JTB6, respectively. The second robot arm 200 is a vertical multi-joint robot arm, but may be any type of robot arm. For example, the second robot arm 200 may be a horizontal multi-joint robot arm, a polar coordinate robot arm, a cylindrical coordinate robot arm, a rectangular coordinate robot arm, or any other type of robot arm. In addition, the number of links of the second robot arm 200 is not limited to seven, but may be six or less or eight or more, and the number of joints of the second robot arm 200 is not limited to six, but may be five or less or seven or more.

For the first robot arm 100, the link 103 is located at the base of the first robot arm 100 and is fixed to the support surface S. Although not limited to this, in this embodiment, the link 103 has a platform shape and functions as a base for the links 101 and 102. The link 102 is located at the tip of the first robot arm 100, and the link 101 is located between the links 102 and 103. The link 103 is an example of a base link.

Joint JTA1 is a one-degree-of-freedom rotary joint that connects one end of columnar link 101 to link 103 so that it can rotate around a first axis S1. Joint JTA2 is a one-degree-of-freedom rotary joint that connects one end of columnar link 102 to the other end of link 101 so that it can rotate around a second axis S2. A second robot arm 200 is attached to the other end of link 102. Thus, links 101 and 102 can be operated by joints JTA1 and JTA2.

In this embodiment, the first axis S1 extends in a direction along the support surface S, for example, in the horizontal direction, and the second axis S2 extends in a direction perpendicular to the support surface S, for example, in the vertical direction. The link 101 can rotate in a direction along a plane perpendicular to the support surface S, and the link 102 can rotate in a direction along the support surface S. Note that the directions of the first axis S1 and the second axis S2 may be any direction, and may be different or the same. The first axis S1 and the second axis S2 are also the joint axes of the joints JTA1 and JTA2, respectively.

The drive units MA1 and MA2 are configured to rotate and drive the joints JTA1 and JTA2, respectively. The drive units MA1 and MA2 each include an electric motor (not shown) as a drive source, and a reducer (not shown). The reducer of the drive units MA1 and MA2 each reduces the rotational speed of the rotational drive force of the respective electric motor and increases the rotational drive force to transmit it to the joints JTA1 and JTA2. In this embodiment, the electric motor is a servo motor.

In this specification and claims, "horizontal direction" and "vertical direction" respectively mean "horizontal direction" and "vertical direction" when the robot 1 is placed on a horizontal support surface S. Furthermore, "upward direction" means an upward direction perpendicular to the support surface S in a similar case, that is, a vertically upward direction, and "downward direction" means a downward direction perpendicular to the support surface S in a similar case, that is, a vertically downward direction. Furthermore, in this specification and claims, "vertical," "vertical," "horizontal," and "parallel" may each include cases where they are completely vertical, vertical, horizontal, or parallel, and cases where they can be considered to be substantially vertical, vertical, horizontal, or parallel, including close to completely vertical, vertical, horizontal, or parallel.

For the second robot arm 200, the link 207 is located at the base of the second robot arm 200 and is fixed to the upper surface of the link 102. The link 207 is located higher than the first robot arm 100. The interface 110 between the link 207 and the link 102 is an example of a connection portion of the robot arms 100 and 200. Although not limited to this, in this embodiment, the center point 110A of the interface 110 is the reference point of the robot arms 100 and 200. In the following, the "interface 110" may be expressed as the "connection portion 110", and the "center point 110A" may be expressed as the "reference point 110A".

In this embodiment, but not limited to this, link 207 has a platform shape and functions as a base for links 201 to 206. Link 206 is located at the tip of second robot arm 200, and links 201 to 205 are arranged in this order between links 206 and 207, from link 207 to link 206. An end effector E capable of acting on a work object W is attached to the tip of link 206. In this embodiment, but not limited to this, end effector E is configured to be able to grasp object W.

All of joints JTB1 to JTB6 are one-degree-of-freedom rotational joints that can rotate around one axis. Joint JTB1 rotatably connects link 201 to link 207. Joint JTB2 rotatably connects link 202 to link 201. Joint JTB3 rotatably connects link 203 to link 202. Joint JTB4 rotatably connects link 204 to link 203. Joint JTB5 rotatably connects link 205 to link 204. Joint JTB6 rotatably connects link 206 to link 205.

The driving devices MB1 to MB6 are configured to rotate and drive the joints JTB1 to JTB6, respectively. Each of the driving devices MB1 to MB6 includes an electric motor (not shown) as a driving source, and a reduction gear (not shown). In this embodiment, the electric motor is a servo motor.

In this embodiment, the control device 300 is configured to control the operation of the entire robot 1, although this is not limited thereto. The control device 300 includes an information processing device 300A and a robot controller 300B. The robot controller 300B is configured to control the operation of the robot arms 100 and 200. The information processing device 300A is configured to perform arithmetic processing related to the operation control of the robot arms 100 and 200.

The information processing device 300A and the robot controller 300B include computer devices. The configuration of the information processing device 300A is not particularly limited, but for example, the information processing device 300A may be an electronic circuit board, an electronic control unit, a microcomputer, a personal computer, a workstation, a smart device such as a smartphone or a tablet, or other electronic device. The robot controller 300B may include an electric circuit for controlling the power supplied to the robot arms 100 and 200, etc.

[Hardware configuration of the control device]
With reference to FIG. 3, the hardware configuration of the control device 300 according to the embodiment will be described. FIG. 3 is a block diagram showing an example of the hardware configuration of the control device 300 according to the embodiment. The information processing device 300A includes a processor 301A, a memory 302A, a storage 303A, and an input/output I/F (interface) 304A as components. The components of the information processing device 300A are connected to each other by a bus 310A, but may be connected by any other wired communication or wireless communication. The robot controller 300B includes a processor 301B, a memory 302B, an input/output I/F 304B, and drive I/Fs 305B and 306B as components. The robot controller 300B may include a storage. The components of the robot controller 300B are connected to each other by a bus 310B, but may be connected by any other wired communication or wireless communication. Not all of the components included in the information processing device 300A and the robot controller 300B are essential.

The pair of processor 301A and memory 302A, and the pair of processor 301B and memory 302B each constitute a computing unit. The computing unit transmits and receives commands, information, data, etc. to and from other devices. The computing unit receives inputs of signals from various devices and outputs control signals to each control target.

Memories 302A and 302B store programs executed by processors 301A and 301B, and various fixed data, etc. Memories 302A and 302B may be configured with storage devices such as semiconductor memories, including volatile and non-volatile memories. Although not limited thereto, in this embodiment, memories 302A and 302B include RAM (Random Access Memory), which is a volatile memory, and ROM (Read-Only Memory), which is a non-volatile memory.

Storage 303A stores various data. Storage 303A may be configured with a storage device such as a semiconductor memory, a hard disk drive (HDD: Hard Disk Drive), or a solid state drive (SSD: Solid State Drive).

Both processors 301A and 301B form a computer system together with RAM and ROM. The computer system of information processing device 300A may realize the functions of information processing device 300A by processor 301A using RAM as a work area to execute a program recorded in ROM. The computer system of robot controller 300B may realize the functions of robot controller 300B by processor 301B using RAM as a work area to execute a program recorded in ROM.

Some or all of the functions of the information processing device 300A and the robot controller 300B may be realized by the above-mentioned computer system, by a dedicated hardware circuit such as an electronic circuit or an integrated circuit, or by a combination of the above-mentioned computer system and hardware circuit. The information processing device 300A and the robot controller 300B may each be configured to execute each process by centralized control of a single device, or may be configured to execute each process by distributed control through the cooperation of multiple devices. The information processing device 300A and the robot controller 300B may be configured to include at least some of each other's functions, or may be integrated.

For example, but not limited to, processors 301A and 301B may include a CPU (Central Processing Unit), MPU (Micro Processing Unit), GPU (Graphics Processing Unit), microprocessor, processor core, multiprocessor, ASIC (Application-Specific Integrated Circuit), FPGA (Field Programmable Gate Array), etc., and each process may be realized by a logic circuit or a dedicated circuit formed in an IC (Integrated Circuit) chip, LSI (Large Scale Integration), etc. Multiple processes may be realized by one or multiple integrated circuits, or may be realized by a single integrated circuit.

The input/output I/F 304A of the information processing device 300A connects the information processing device 300A and the robot controller 300B, enabling input/output of information, commands, data, etc. between them. The input/output I/F 304B of the robot controller 300B connects the robot controller 300B and the input/output I/F 304A of the information processing device 300A, enabling input/output of information, commands, data, etc. between them.

The first drive I/F 305B connects the robot controller 300B and the first drive circuit 120 of the first robot arm 100, enabling transmission and reception of signals between them. The first drive circuit 120 is configured to control the power supplied to the drive devices MA1 and MA2 of the first robot arm 100 according to a command value included in a signal received from the robot controller 300B.

The second drive I/F 306B connects the robot controller 300B and the second drive circuit 220 of the second robot arm 200, enabling the transmission and reception of signals between them. The second drive circuit 220 is configured to control the power supplied to the drive units MB1 to MB6 of the second robot arm 200 according to command values contained in signals received from the robot controller 300B.

The robot controller 300B may be configured to servo-control the servo motors of the drive units MA1, MA2, and MB1 to MB6. The robot controller 300B receives the detection values of the rotation sensors equipped in each servo motor and the current command values from the drive circuits 120 and 220 to each servo motor as feedback information from the drive circuits 120 and 220. The robot controller 300B uses the feedback information to determine the drive command values for each servo motor and transmits them to the drive circuits 120 and 220.

The robot controller 300B may be configured to enable the axis controls of multiple servo motors to be coordinated with each other. The robot controller 300B may be configured to control the servo motors of the drive units MB1 to MB6 as robot axis control, which is a part of the multiple axis controls, and to control the servo motors of the drive units MA1 and MA2 as external axis control, which is a part of the multiple axis controls.

[Functional configuration of the control device]
The functional configuration of the control device 300 according to the embodiment will be described with reference to FIG. 4. FIG. 4 is a block diagram showing an example of the functional configuration of the control device 300 according to the embodiment. The information processing device 300A includes a first operation command unit 401, a second operation command unit 402, a first estimation unit 403, a second estimation unit 404, a third estimation unit 405, a fourth estimation unit 406, a first position estimation unit 407, a second position estimation unit 408, an inertial element estimation unit 409, an inertial force estimation unit 410, a correction command unit 411, and memory units 421 to 423 as functional components. The functions of the functional components other than the memory units 421 to 423 are realized by the processor 301A or the like, and the functions of the memory units 421 to 423 are realized by a storage device such as the memory 302A and/or the storage 303A. The functions of the storage units 421 to 423 may be realized by separate storage devices, or at least two of the functions of the storage units 421 to 423 may be realized by one storage device. All of the above functional components are not essential.

The robot controller 300B includes a first drive command unit 501 and a second drive command unit 502 as functional components. The functions of the drive command units 501 and 502 are realized by the processor 301B, etc. Not all of the above functional components are essential.

The storage units 421 to 423 store various information and data, and enable the stored information and data to be read. For example, the first storage unit 421 stores a control program for the robot arms 100 and 200. Although not limited to this, in this embodiment, the control device 300 is configured to cause the robot arms 100 and 200 to operate autonomously according to the control program, that is, to cause the robot arms 100 and 200 to operate automatically. The first storage unit 421 may store target operation data such as teaching data for causing the robot arms 100 and 200 to operate autonomously. Note that the control device 300 may be configured to cause the robot arms 100 and 200 to operate according to an operation command received from an operation device (not shown), that is, to cause the robot arms 100 and 200 to operate manually.

For example, the second storage unit 422 stores information about the first robot arm 100. The information about the first robot arm 100 includes information about the links 101 to 103 and the joints JTA1 and JTA2. The information about the links 101 to 103 may include information about the mass, dimensions, shape, center of gravity, moment of inertia, rigidity, and connection position with the joints of each of the links 101 to 103. The rigidity of the links may include bending rigidity and torsional rigidity of the links. The information about the joints JTA1 and JTA2 may include information about the mass, dimensions, shape, center of gravity, moment of inertia, rigidity, position and direction of the rotation axis of each of the joints JTA1 and JTA2, and connection position with the links. The rigidity of the joints may include the rigidity of the members that make up the joints, the rigidity of the rotating parts of the joints, and the rigidity of the reduction gears of the joints.

The information on links 101 to 103 may be a virtual model in which the above information on links 101 to 103 is reflected, and the information on joints JTA1 and JTA2 may be a virtual model in which the above information on joints JTA1 and JTA2 is reflected. For example, the virtual model may be a three-dimensional model such as a three-dimensional CAD (Computer-Aided Design) model.

For example, the third memory unit 423 stores information on the second robot arm 200. The information on the second robot arm 200 includes information on the links 201-207 and the joints JTB1-JTB6. Furthermore, the information on the second robot arm 200 may include information on the end effector E attached to the second robot arm 200, and information on an object W such as a workpiece held by the end effector E. The information on the links 201-207 may include information on the mass, dimensions, shape, center of gravity position, moment of inertia, and connection position with the joints of each of the links 201-207. The information on the joints JTB1-JTB6 may include information on the mass, dimensions, shape, center of gravity position, moment of inertia, position and direction of the rotation center axis of each of the joints JTB1-JTB6, and connection position with the links. The information on the end effector E may include information such as its mass, dimensions, shape, center of gravity, moment of inertia, and connection position with the link 206. The information on the object W may include information such as its mass, dimensions, shape, center of gravity, and posture when held. The information on the links 201-207, the joints JTB1-JTB6, the end effector E, and the object W may be virtual models that reflect the above information for each of them. For example, the virtual model may be a three-dimensional model such as a three-dimensional CAD model.

The first operation command unit 401 generates an operation command (hereinafter also referred to as a "first operation command") for causing the first robot arm 100 to execute a target operation according to the first target operation data, which is the target operation data of the first robot arm 100 stored in the first memory unit 421. The first target operation data is data for operating the first robot arm 100 according to a control program. For example, the first operation command unit 401 calculates a target position and a target posture of the connection part 110 for moving the connection part 110 according to the first target operation data, using information of the first robot arm 100 stored in the second memory unit 422. The target position and the target posture may be the three-dimensional position of the reference point 110A and the three-dimensional posture of the interface of the connection part 110.

Furthermore, the first operation command unit 401 calculates the target rotation direction and the target rotation amount of the joints JTA1 and JTA2 for moving the connection part 110 to the target position and the target posture, using the information of the first robot arm 100 stored in the second storage unit 422. That is, the first operation command unit 401 calculates the target rotation positions of the joints JTA1 and JTA2. The first operation command unit 401 may be configured to calculate the target rotation positions of the joints JTA1 and JTA2 using the first target operation data and the information of the first robot arm 100. The first operation command unit 401 generates a first operation command including the target rotation positions of the joints JTA1 and JTA2. In the case of manual operation, the first operation command unit 401 generates a first operation command in the same manner as described above for causing the first robot arm 100 to execute a target operation according to an operation command received from an operation device (not shown).

The second operation command unit 402 generates an operation command (hereinafter also referred to as a "second operation command") for causing the second robot arm 200 to execute a target operation according to second target operation data, which is target operation data for the second robot arm 200 stored in the first memory unit 421. The second target operation data is data for operating the second robot arm 200 according to a control program. For example, the second operation command unit 402 calculates a target position and target posture of the link 206 for moving the link 206 according to the second target operation data using information of the second robot arm 200 stored in the third memory unit 423. The target position and target posture may be a three-dimensional position and three-dimensional posture of the tip of the link 206.

Furthermore, the second operation command unit 402 calculates the target rotation direction and the target rotation amount of the joints JTB1 to JTB6 for moving the link 206 to the target position and the target posture, using the information of the second robot arm 200 stored in the third storage unit 423. That is, the second operation command unit 402 calculates the target rotation positions of the joints JTB1 to JTB6. The second operation command unit 402 may be configured to calculate the target rotation positions of the joints JTB1 to JTB6 using the second target operation data and the information of the second robot arm 200. The second operation command unit 402 generates a second operation command including the target rotation positions of the joints JTB1 to JTB6. In the case of manual operation, the second operation command unit 402 generates a second operation command in the same manner as described above for causing the second robot arm 200 to execute a target operation according to an operation command received from an operation device (not shown).

The first estimation unit 403 acquires a first motion command from the first motion command unit 401, and estimates the motions of the joints JTA1 and JTA2 when the first robot arm 100 operates according to the first motion command. For example, the first estimation unit 403 calculates estimated rotational positions, which are estimates of the rotational positions of the joints JTA1 and JTA2, as the motions of the joints JTA1 and JTA2. The estimated rotational positions of the joints JTA1 and JTA2 include estimated values of the rotation direction and rotation amount of the joints JTA1 and JTA2. The estimated rotational positions of the joints JTA1 and JTA2 correspond to the target rotational positions of the joints JTA1 and JTA2 included in the first motion command. Furthermore, the first estimation unit 403 calculates estimated rotational speeds, which are estimates of the rotational speeds of the joints JTA1 and JTA2, based on the estimated rotational positions of the joints JTA1 and JTA2.

The second estimation unit 404 obtains a second operation command from the second operation command unit 402, and estimates the force that the connection part 110 receives from the second robot arm 200 at the reference point 110A when the second robot arm 200 operates according to the second operation command. Although not limited to this, in the present embodiment, the second estimation unit 404 estimates the above force using a reference coordinate system with the reference point 110A as the origin O.

The reference coordinate system may be a coordinate system with the reference point 110A as the origin O. Although not limited thereto, in this embodiment, the reference coordinate system is defined by the X-axis and Y-axis that extend from the reference point 110A along the interface of the connection part 110 and are mutually orthogonal, and the Z-axis that extends from the reference point 110A in a direction perpendicular to the interface of the connection part 110 and is orthogonal to the X-axis and Y-axis, as shown in FIG. 2. The positive direction of the Z-axis is the direction from the link 207 toward the link 102. Alternatively, for example, the reference coordinate system may be defined by the X-axis and Y-axis that extend horizontally from the reference point 110A and are mutually orthogonal, and the Z-axis that extends vertically downward from the reference point 110A and is orthogonal to the X-axis and Y-axis. The vertical downward direction may be the direction of gravity, and the horizontal direction may be a direction perpendicular to the direction of gravity.

For example, the above force may include the load of the second robot arm 200 and a moment generated by the second robot arm 200 at the connection portion 110. For example, the second estimation unit 404 may estimate the positions and orientations of the links 201-207 and the joints JTB1-JTB6 when the second robot arm 200 operates according to the second operation command, and estimate the above force using the estimation results and information about the second robot arm 200 stored in the third memory unit 423.

The load of the second robot arm 200 may include the mass of the second robot arm 200 itself, the mass of the end effector E, and the mass of the object W held by the end effector E. The moment of the second robot arm 200 may include a moment generated at the connection portion 110 between the second robot arm 200 itself, the end effector E, and the object W. The second estimation unit 404 calculates the load and moment of the second robot arm 200 using the information of the second robot arm 200 stored in the third memory unit 423 and the target rotation positions of the joints JTB1 to JTB6 included in the second operation command. The second estimation unit 404 represents the load and moment of the second robot arm 200 using a reference coordinate system. Furthermore, the second estimation unit 404 calculates the moment of inertia of the entire second robot arm 200 based on the reference coordinate system, using the information on the second robot arm 200 stored in the third storage unit 423 and the target rotation positions of the joints JTB1 to JTB6 included in the second operation command. This moment of inertia is the moment of inertia based on the origin O of the reference coordinate system.

The third estimation unit 405 estimates the forces acting on the links 101 to 103 based on the movements of the joints JTA1 and JTA2 estimated by the first estimation unit 403 and the force acting on the connection part 110 from the second robot arm 200 estimated by the second estimation unit 404. Although not limited to this, in this embodiment, the trapezoidal link 103 is immobile with almost no deformation such as bending even when it receives a force through the link 101 and the joint JTA1, so the third estimation unit 405 estimates the forces acting on the links 101 and 102.

For example, the third estimation unit 405 estimates the force acting on the links 101 and 102 based on the inertial force acting on the links 101 and 102, which is estimated by the inertial force estimation unit 410 based on the movements of the joints JTA1 and JTA2 estimated by the first estimation unit 403, and the force acting on the connection part 110 from the second robot arm 200.

The fourth estimation unit 406 estimates at least one of the deformation amounts of the links 101 and 102 and the deformation amounts of the joints JTA1 and JTA2 based on the forces acting on the links 101 and 102 estimated by the third estimation unit 405. In this embodiment, the fourth estimation unit 406 estimates both the deformation amounts of the links 101 and 102 and the deformation amounts of the joints JTA1 and JTA2.

The first position estimation unit 407 estimates the positions and postures of the links 101 and 102 and the joints JTA1 and JTA2. The first position estimation unit 407 estimates the three-dimensional positions and three-dimensional postures of the links 101 and 102 and the joints JTA1 and JTA2 using a reference coordinate system. For example, the first position estimation unit 407 uses the estimated rotational positions of the joints JTA1 and JTA2 estimated by the first estimation unit 403 and the information of the first robot arm 100 stored in the second storage unit 422 to calculate the estimated positions and estimated postures of the links 101 and 102 and the joints JTA1 and JTA2 at the estimated rotational positions. The first position estimation unit 407 calculates the moments of inertia of the links 101 and 102 based on the estimated positions and estimated postures of the links 101 and 102 and the joints JTA1 and JTA2 based on the estimated positions and estimated postures of the links 101 and 102 and the joints JTA1 and JTA2. The moment of inertia is the moment of inertia with respect to the origin O of the reference coordinate system.

The second position estimation unit 408 estimates the position of the connection part 110. Specifically, the second position estimation unit 408 estimates the three-dimensional position of the reference point 110A of the connection part 110 and the three-dimensional orientation of the interface of the connection part 110 using a reference coordinate system. For example, the first position estimation unit 407 may calculate the estimated position and estimated orientation of the connection part 110 at the estimated rotation position using the estimated rotation positions of the joints JTA1 and JTA2 estimated by the first estimation unit 403 and the information of the first robot arm 100 stored in the second storage unit 422. The second position estimation unit 408 may calculate the estimated position and estimated orientation of the connection part 110 using the estimated positions and estimated orientations of the links 101 and 102 and the joints JTA1 and JTA2 estimated by the first position estimation unit 407. The second position estimation unit 408 may obtain the target position and target orientation of the connection part 110 corresponding to the target rotational positions of the joints JTA1 and JTA2 from the first operation command unit 401, and convert the target position and target orientation into a reference coordinate system to obtain an estimated position and estimated orientation.

The inertial element estimation unit 409 estimates the inertial characteristics of the links 101 to 103 and the inertial characteristics of the second robot arm 200. Although not limited to this, in this embodiment, since link 103 is immobile with almost no deformation such as bending even when it receives a force via link 101 and joint JTA1, the inertial element estimation unit 409 estimates the inertial characteristics of links 101 and 102. The inertial characteristics of links 101 and 102 include the inertial moment and mass of links 101 and 102 as elements. The inertial characteristics of the second robot arm 200 include the inertial moment and mass of the second robot arm 200 as elements.

The inertial force estimation unit 410 estimates the inertial forces (hereinafter also referred to as "joint-induced inertial forces") generated in the links 101 to 103 due to the movements of the joints JTA1 and JTA2, based on the movements of the joints JTA1 and JTA2 estimated by the first estimation unit 403. Although not limited to this, in this embodiment, the link 103 is immobile with almost no deformation such as bending even when it receives a force via the link 101 and the joint JTA1, so the inertial force estimation unit 410 estimates the joint-induced inertial forces generated in the links 101 and 102.

Specifically, the inertial force estimation unit 410 estimates the joint-induced inertial forces occurring in the links 101 and 102 using the inertial characteristics of the links 101 and 102, the inertial characteristics of the second robot arm 200, the accelerations of the joints JTA1 and JTA2, and the joint screws of the joints JTA1 and JTA2. The joint screws of the joints JTA1 and JTA2 are each a feature indicating the state of the joint, including an element indicating the orientation of the joint.

Based on the deformation amount of the links 101 and 102 and/or the deformation amount of the joints JTA1 and JTA2 estimated by the fourth estimation unit 406, the correction command unit 411 generates a correction command for the first operation command to compensate for the deformation amount so as to move the connection part 110 according to the first target operation. The correction command unit 411 outputs the correction command to the first robot arm 100, specifically, to the first drive command unit 501. Although not limited to this, in this embodiment, the correction command unit 411 corrects the first operation command to compensate for the deformation amount, and generates the corrected first operation command as a correction command. When the correction command unit 411 does not correct the first operation command, it outputs the uncorrected first operation command as a correction command to the first drive command unit 501. In addition, the correction command unit 411 outputs the second operation command to the second robot arm 200, specifically, to the second drive command unit 502.

The first drive command unit 501 generates a drive command for the drive devices MA1 and MA2 to drive the joints JTA1 and JTA2 to the target rotation positions of the joints JTA1 and JTA2 included in the correction command, and outputs the drive command to the drive devices MA1 and MA2. The drive command includes a command value for the current of the servo motors of the drive devices MA1 and MA2. The first drive command unit 501 generates the drive command using feedback information of the servo motors.

The second drive command unit 502 generates a drive command for driving the drive devices MB1 to MB6 to drive the joints JTB1 to JTB6 to the target rotation positions of the joints JTB1 to JTB6 included in the second operation command, and outputs the drive command to the drive devices MB1 to MB6. The drive command includes command values for the currents of the servo motors of the drive devices MB1 to MB6. The second drive command unit 502 generates the drive command using feedback information of the servo motors.

[Operation of the control device]
The operation of the control device 300 will be described with reference to Fig. 5. Fig. 5 is a flowchart showing an example of the operation of the control device 300 according to the embodiment. First, in the information processing device 300A, the first operation command unit 401 generates a first operation command for operating the first robot arm 100 in accordance with the first target operation data stored in the first storage unit 421 (step S101).

Next, the second operation command unit 402 generates a second operation command for operating the second robot arm 200 according to the second target operation data stored in the first memory unit 421 (step S102).

Next, the first estimation unit 403 estimates the movements of the joints JTA1 and JTA2 when the first robot arm 100 moves according to the first movement command (step S103). The first estimation unit 403 calculates the estimated rotational positions and estimated rotational velocities of the joints JTA1 and JTA2 as the movements to be estimated.

Next, the first position estimation unit 407 estimates the positions and orientations of the links 101 and 102 and the joints JTA1 and JTA2 when the first robot arm 100 operates according to the first operation command (step S104). For example, the first position estimation unit 407 may calculate the estimated positions and orientations of the links 101 and 102 and the joints JTA1 and JTA2 using the estimated rotational positions of the joints JTA1 and JTA2 estimated by the first estimation unit 403 and the information of the first robot arm 100 stored in the second storage unit 422.

For example, the first position estimation unit 407 calculates the estimated positions of the centers of gravity of the links 101 and 102 based on the reference coordinate system as the estimated positions of the links 101 and 102. For example, the first position estimation unit 407 calculates an estimated position vector γ _g1о of the center of gravity of the first link 101 in the reference coordinate system and an estimated position vector γ _g2о of the center of gravity of the second link 102 in the reference coordinate system. In the following, the position vector of the i-th link based on the reference point 110A, which is the origin O of the reference coordinate system, is represented as "γ _gio ". The link number "i" increases from the base end to the tip end of the first robot arm 100. Note that the first position estimation unit 407 may be configured to calculate the estimated positions of other reference points set on the links 101 and 102 based on the reference coordinate system.

For example, the first position estimation unit 407 calculates the estimated positions of the centers of gravity of the joints JTA1 and JTA2 and the estimated orientations of the reference axes as the estimated positions and orientations of the joints JTA1 and JTA2 with reference to the reference coordinate system. For example, the first position estimation unit 407 calculates an estimated position vector γ _1о of the center of gravity of the first joint JTA1 in the reference coordinate system and an estimated position vector γ _2о of the center of gravity of the second joint JTA2 in the reference coordinate system. In the following, the position vector of the j-th joint with reference to the origin O of the reference coordinate system is represented as "γ _jо ". The joint number "j" increases from the base end to the tip end of the first robot arm 100. Note that the first position estimation unit 407 may be configured to calculate the estimated positions of other reference points set in the joints JTA1 and JTA2 with reference to the reference coordinate system.

For example, the first position estimation unit 407 calculates an estimated direction vector d _1o of the first joint JTA1 in the reference coordinate system and an estimated direction vector d _2o of the second joint JTA2 in the reference coordinate system as estimated attitudes of the reference axes of the joints JTA1 and JTA2. Hereinafter, the direction vector of the jth joint based on the origin O of the reference coordinate system is represented as "d _jo ". The direction vector d _jo is a vector indicating the direction of the reference axis of the movement of the jth joint. For example, when the jth joint is a rotating joint, the direction vector d _jo is a direction vector of the rotation center axis, which is the joint axis. When the jth joint is a linear joint, the direction vector d _jo is a direction vector of the linear axis, which is the joint axis.

Furthermore, the first position estimation unit 407 calculates moments of inertia l 1O and l 2O of the links 101 and 102 with respect to the origin O of the reference coordinate system, using the estimated positions of the links 101 and 102 and the estimated positions and orientations of the joints _JTA1 and _JTA2 , and information on the first robot arm 100 stored in the second storage unit 422. Hereinafter, the moment of inertia of the i-th link with respect to the origin O of the reference coordinate system is represented as "l _iO ".

Next, the second position estimation unit 408 estimates the position and orientation of the connection part 110 when the first robot arm 100 operates according to the first operation command (step S105). For example, the first position estimation unit 407 may calculate the estimated position and estimated orientation of the connection part 110 using the estimated positions and estimated orientations of the links 101 and 102 and the joints JTA1 and JTA2 estimated by the first position estimation unit 407 and information on the first robot arm 100 stored in the second memory unit 422.

The second position estimation unit 408 calculates the estimated position of the reference point 110A and the estimated posture of the interface of the connection part 110 with reference to the robot coordinate system. In other words, the second position estimation unit 408 calculates the estimated position and estimated posture of the reference coordinate system with reference to the robot coordinate system. The robot coordinate system is a coordinate system defined with reference to the robot 1. Although not limited to this, in this embodiment, as shown in FIG. 2, the origin Or of the robot coordinate system is set to the position of the link 103 on the support surface S. The Xr axis and the Yr axis extend from the origin Or along the support surface S and are orthogonal to each other. The Zr axis extends from the origin Or perpendicularly upward to the support surface S and is orthogonal to the Xr axis and the Yr axis.

Next, the second estimation unit 404 estimates the force that the connection part 110 receives from the second robot arm 200 when the second robot arm 200 operates in accordance with the second operation command (step S106). The force includes the load of the second robot arm 200 and a moment that the second robot arm 200 generates at the connection part 110. For example, the second estimation unit 404 calculates estimated positions and attitudes of the links 201-207 and the joints JTB1-JTB6 based on the reference coordinate system, based on the target rotation positions of the joints JTB1-JTB6 included in the second operation command. Furthermore, the second estimation unit 404 uses the estimated positions and orientations of the links 201-207 and the joints JTB1-JTB6, the estimated position and orientation of the connection part 110 estimated by the second position estimation unit 408, and information on the second robot arm 200 stored in the third storage unit 423 to calculate the moment that the second robot arm 200 generates at the connection part 110 and the load of the second robot arm 200, based on the reference coordinate system.

Furthermore, the second estimation unit 404 uses the estimated positions and orientations of the links 201-207 and the joints JTB1-JTB6, and information on the second robot arm 200, to calculate an estimated center of gravity position, which is the center of gravity position of the entire second robot arm 200, and an estimated moment of inertia, which is the moment of inertia of the entire second robot arm 200. At this time, the second estimation unit 404 may use, as information on the second robot arm 200, the center of gravity positions and masses of the links 201-207, the center of gravity positions and masses of the joints JTB1-JTB6, the center of gravity position and mass of the end effector E, and the center of gravity position and mass of the object W, etc.

Next, the inertial element estimation unit 409 estimates the inertial characteristics of each of the links 101 and 102 of the first robot arm 100 and the inertial characteristics of the entire second robot arm 200 (step S107). The inertial element estimation unit 409 calculates each inertial characteristic based on the reference coordinate system using the information of the first robot arm 100 stored in the second storage unit 422 and the information of the second robot arm 200 stored in the third storage unit 423.

In the following, the inertial characteristic of the i-th link is represented as "L _io ", and the inertial characteristic of the entire second robot arm 200 is represented as "L _ao ". The inertial characteristics "L _io " and "L _ao " are based on the origin O of the reference coordinate system. The inertial characteristic L _io is a 6×6 matrix representing the mass and moment of inertia of the i-th link. The inertial characteristic L _ao is a 6×6 matrix representing the mass and moment of inertia of the entire second robot arm 200. The inertial element estimation unit 409 calculates the inertial characteristics L _io and L _ao using the following equations 1 and 2, respectively. The inertial characteristics L _io and L _ao shown in equations 1 and 2 are also called inertial biners.

In formula 1, element "m _i " is the mass of the i-th link and is a scalar. Element "l _iO " is a 3 x 3 matrix representing the moment of inertia of the i-th link. Element "E" is an identity matrix. Element "γ_ぎＯ� " is the three-dimensional position vector of the center of gravity of the i-th link. [γ_ぎＯ� ×] is the cross product of the position vector γ_ぎＯ� expressed as a skew-symmetric matrix, and is also called the cross product matrix of the position vector γ_ぎＯ� .

In Equation 2, the element "m _a " is the mass of the entire second robot arm 200, and is a scalar. The element "l _aO " is a 3×3 matrix representing the moment of inertia of the entire second robot arm 200. The element "γ _gaO " is a three-dimensional position vector of the center of gravity of the entire second robot arm 200. [γ _gaO ×] is a cross product of the position vector γ _gaO expressed as a skew-symmetric matrix.

Next, the inertial force estimation unit 410 estimates the inertial forces (joint-induced inertial forces) generated in the links 101 and 102 due to the movements of the joints JTA1 and JTA2, based on the movements of the joints JTA1 and JTA2 estimated by the first estimation unit 403 (step S108). The inertial force estimation unit 410 calculates the joint-induced inertial forces generated in the links 101 and 102 using the estimated rotational positions of the joints JTA1 and JTA2 estimated by the first estimation unit 403 and the inertial characteristics estimated by the inertial element estimation unit 409.

Specifically, the inertia force estimating unit 410 calculates the joint screw of each of the joints JTA1 and JTA2. The joint screw of the j-th joint is represented as "M _j0 ". The inertia force estimating unit 410 calculates an estimated joint screw M ₁₀ of the first joint JTA1 and an estimated joint screw M ₂₀ of the second joint JTA2 based on a reference coordinate system. The joint screw M _j0 is represented by a six-dimensional vector.

In this embodiment, both of the joints JTA1 and JTA2 are rotational joints that can rotate around one rotation central axis. For example, the inertial force estimator 410 calculates an estimated joint screw M _j0 of the j-th joint as shown in the following formula 3. In formula 3, γ _j0 ×d _j0 indicates the cross product of γ _j0 and d _j0 . The element "γ _j0 " is a three-dimensional estimated position vector of the j-th joint, and the element "d _j0 " is a three-dimensional estimated direction vector of the j-th joint. The estimated direction vector d _j0 of the j-th joint indicates the direction vector of the rotation central axis, which is the joint axis of the j-th joint.

The above formula 3 shows the joint screw of the j-th joint when the j-th joint is a rotary joint, but even if the j-th joint is another type of joint, the joint screw of the j-th joint can be calculated. For example, when the j-th joint is a linear joint, the joint screw of the j-th joint can be expressed as the following formula 4. When the j-th joint is a screw joint, the joint screw of the j-th joint can be expressed as the following formula 5. In formula 4, the element "d _jо " indicates the direction vector of the axis of linear motion, which is the joint axis of the j-th joint. In formula 5, the element "d _jо " indicates the direction vector of the rotation center axis of the screw rotation, which is the joint axis of the j-th joint, and the direction vector is also the direction vector of the axis of advancement and retreat by the screw rotation. The screw joint is configured to advance and retreat the link in the direction of the rotation center axis when the link connected to the screw joint rotates around the rotation center axis. The element "h" indicates the pitch of the screw rotation, and indicates, for example, the amount of advancement and retreat of the link in the direction of the rotation center axis per rotation of one radian.

Furthermore, the inertial force estimator 410 estimates the accelerations of the joints JTA1 and JTA2. The accelerations are the accelerations generated by the joints JTA1 and JTA2 when the joints JTA1 and JTA2 move to the estimated rotation positions. For example, the inertial force estimator 410 calculates the estimated accelerations θ ₁ ^″ and θ ₂ ^″ of the joints JTA1 and JTA2, respectively, by time-differentiating the estimated rotational speeds of the joints JTA1 and JTA2, respectively, estimated by the first estimator 403.

The inertial force estimating unit 410 uses the inertial characteristics L _1o , L _{2o ,} and L _ao , the joint screws M _1o and M _2o , and the estimated accelerations θ ₁ ^″ and θ ₂ ^″ to calculate the joint-induced inertial force F _ijo applied to the i-th link by the estimated accelerations θ ₁ ^″ and θ ₂ ^″ with reference to the reference coordinate system. The joint-induced inertial force F _ijo represents the inertial force generated in the i-th link by the estimated acceleration θ _j ^″ of the j-th joint with reference to the origin O of the reference coordinate system. The joint-induced inertial force F _ijo includes three translational components and three rotational components, and is expressed as a six-dimensional vector. The inertial force estimating unit 410 calculates the joint-induced inertial forces F _11o , F _12o , F _21o , and F _22o generated in the links 101 and 102 due to the estimated accelerations θ ₁ ^″ and θ ₂ ^″ as shown in the following equations 6 to 9. The joint-induced inertial force F _ijo includes, as elements, the inertial characteristics of the link that moves as a result of the operation of the j-th joint, and the inertial characteristics of the second robot arm 200.

Next, the third estimation unit 405 estimates the force acting on the links 101 and 102 based on the joint-induced inertial force estimated by the inertial force estimation unit 410 and the force estimated by the second estimation unit 404 (step S109). The third estimation unit 405 uses the estimated inertial force F _ao of the second robot arm 200 as the force estimated by the second estimation unit 404. The estimated inertial force F _ao may be the inertial force applied by the second robot arm 200 to the origin O of the reference coordinate system, with the origin O being used as a reference. Although not limited thereto, in this embodiment, the load and moment of the second robot arm 200 estimated by the second estimation unit 404 are used as the estimated inertial force F _ao . The estimated inertial force F _ao includes three directional components of the load and three directional components of the moment, and is expressed as a six-dimensional vector.

The third estimator 405 uses the joint-induced inertial force F _ijO and the estimated inertial force F _ao to calculate an estimated inertial force F _io generated in the i-th link with reference to the origin O of the reference coordinate system as a force applied to the i-th link. The estimated inertial force F _io includes three translational components and three rotational components, and is represented by a six-dimensional vector. The third estimator 405 calculates the estimated inertial forces F _1o and F _2o generated in the links 101 and 102 as shown in the following Equations 10 and 11.

Next, the fourth estimation unit 406 estimates the deformation amounts of the links 101 and 102 and the deformation amounts of the joints JTA1 and JTA2 based on the forces acting on the links 101 and 102 estimated by the third estimation unit 405 (step S110).

The fourth estimator 406 calculates the estimated deformation amounts of the joints JTA1 and JTA2 using the stiffnesses k _g1 and k _g2 of the joints JTA1 and JTA2 and the estimated inertial forces F _1o and F _2o included in the information of the first robot arm 100 stored in the second storage unit 422. In this case, the fourth estimator 406 calculates the estimated torques τ ₁ and τ ₂ acting on the joints JTA1 and JTA2, respectively, using the estimated inertial forces F _1o and F _2o and the joint screws M _1o and M _2o , as shown in the following formulas 12 and 13. In the following, the stiffness of the j-th joint is represented as "k _gj " and the estimated torque of the j-th joint is represented as "τ _j ". The stiffness k _gj includes three translational components and three rotational components, and is represented as a six-dimensional vector. The stiffness k _gj includes the spring constant of the reducer, which is the stiffness of the reducer of the j-th joint, etc. The estimated torque τ _j is a scalar.

The operator "o" in formulas 12 and 13 indicates a distribution operation of vectors. For example, in the case where a six-dimensional vector A includes a vector _a1 including a three-dimensional translation component and a vector _a2 including a three-dimensional rotation component, and a six-dimensional vector B includes a vector _b1 including a three-dimensional translation component and a vector _b2 including a three-dimensional rotation component, the operation of vectors A and B using the operator "o" is shown as in formula 14 below.

Furthermore, the fourth estimator 406 calculates an estimated deformation amount _Δθj of the j-th joint by dividing the estimated torque _τj by the stiffness _kgj . The fourth estimator 406 calculates the estimated deformation amounts _Δθ1 and Δθ2 of the joints JTA1 and _JTA2 , respectively, as shown in the following formulas 15 and 16. The estimated deformation amount _Δθj can be a compensation amount for deformation at the j-th joint.

Furthermore, the fourth estimator 406 calculates an estimated deformation amount of the links 101 and 102 using the compliances C _I1o and C _I2o of the links 101 and 102 and the estimated inertial forces F _1o and F _2o included in the information of the first robot arm 100 stored in the second storage unit 422. Hereinafter, the compliance of the i-th link will be represented as "C _Iio ." The compliance C _Iio indicates the stiffness of the i-th link based on the origin O of the reference coordinate system, and is represented by a 6 x 6 matrix.

The fourth estimator 406 uses the estimated inertial forces F _1o and F _2o and the compliances C _I1o and C _I2o to calculate the estimated deformation amounts Δ _1o and Δ _2o of the links 101 and 102, respectively, as shown in the following equations 17 and 18. Hereinafter, the estimated deformation amount of the i-th link will be represented as "Δ _io ." The estimated deformation amount Δ _io includes three translational components and three rotational components, and is represented as a six-dimensional vector based on the reference coordinate system.

Furthermore, the fourth estimator 406 may convert the estimated deformation amount Δ _io of the i-th link into an estimated deformation amount of the j-th joint by using the estimated deformation amount Δ _io of the i-th link and the joint screw M _j of the j-th joint. A vector including a three-dimensional translational component included in the estimated deformation amount Δ _io is defined as a vector δ _tio , and a vector including a three-dimensional translational component included in the joint screw M _jo is defined as a vector υ _jo . The estimated deformation amount Δ _io of the i-th link can be converted into an estimated deformation amount ΔθL _j of the j-th joint as shown in the following formula 19. The estimated deformation amount ΔθL _j can be used as a compensation amount for the deformation of the link.

Next, the correction command unit 411 generates a correction command for the first operation command to compensate for the amount of deformation estimated by the fourth estimation unit 406 so as to move the connection part 110 according to the first target operation (step S111). The correction command unit 411 associates the correction command with the second operation command and transmits them to the robot controller 300B. The correction command unit 411 corrects the first operation command so as to bring the position and orientation of the connection part 110 to the target position and orientation by compensating for the amount of deformation, and transmits the corrected first operation command as a correction command.

For example, the correction command unit 411 may correct the first movement command by adding the estimated deformation amount Δθ _{j of the j-th joint to the target rotation position of the j-th joint included in the first movement command. The correction command unit 411 may correct the first movement command by adding the estimated deformation amount ΔθL j of} the j-th joint to the target rotation position of the j-th joint included in the first movement command. This compensates for the deformation amounts of both the link and the joint. In this embodiment, since the j-th joint is a rotation joint having one degree of freedom, the correction command unit 411 adds one of the estimated deformation amount Δθ _j and the estimated deformation amount ΔθL _j to the target rotation position of the j-th joint, but may also add both to the target rotation position of the j-th joint. When the j-th joint has two or more degrees of freedom, the correction command unit 411 may add both the estimated deformation amount Δθ _j and the estimated deformation amount ΔθL _j to the target rotation position of the j-th joint.

Next, in the robot controller 300B, the drive command units 501 and 502 generate drive commands and output them to the robot arms 100 and 200 (step S112). The first drive command unit 501 generates a drive command according to the correction command and outputs it to the drive units MA1 and MA2 of the first robot arm 100. The second drive command unit 502 generates a drive command according to the second operation command and outputs it to the drive units MB1 to MB6 of the second robot arm 200. The drive command units 501 and 502 output their respective drive commands in cooperation with each other so as to synchronize the output timing of each drive command. As a result, the robot arms 100 and 200 simultaneously execute their respective target operations, but the position and posture of the connection part 110 are prevented from fluctuating from the target position and target posture due to the operations of the two robot arms 100 and 200. Therefore, the second robot arm 200 can accurately perform the target operation on the object W to be acted upon.

(Variation 1)
This modification differs from the embodiment in that the first robot arm 100A has only one joint. Hereinafter, the modification will be described with a focus on the differences from the embodiment, and a description of the same points as the embodiment will be omitted as appropriate.

FIG. 6 is a side view of a model of the configuration of the robot 1A according to the first modification. As shown in FIG. 6, the robot 1A includes a second robot arm 200 similar to that of the embodiment, and a first robot arm 100A. The first robot arm 100A includes links 101A and 102A, and a joint JTAA1 that rotatably connects the links 101A and 102A. Although not limited thereto, the first link 101A of this modification has a configuration similar to that of the second link 102 of the embodiment, and the second link 102A of this modification has a configuration similar to that of the third link 103 of the embodiment. The first joint JTAA1 of this modification has a configuration similar to that of the second joint JTA2 of the embodiment. The robot 1A includes a control device 300 including an information processing device 300A and a robot controller 300B similar to those of the embodiment. The information processing device 300A performs the same processing as that of the embodiment, but performs calculations using a calculation formula that differs from that of the embodiment in the following respects.

The inertial force estimating unit 410 uses the following equation 20 instead of equations 6 to 9 in the embodiment to calculate the joint-derived inertial force F ₁₁₀ generated in the first link 101A due to the estimated acceleration θ ₁ ^″ of the first joint JTAA1.

The third estimator 405 uses the following equation 21 instead of equations 10 and 11 in the embodiment to calculate an estimated inertial force F ₁₀ generated in the first link 101A.

The fourth estimator 406 calculates an estimated torque _τ1 of the first joint JTAA1 using equation 12. Furthermore, the fourth estimator 406 calculates an estimated deformation amount _Δθ1 of the first joint JTAA1 using equation 15. The fourth estimator 406 calculates an estimated deformation amount Δ _1o of the first link 101A using equation 17. The fourth estimator 406 converts the estimated deformation amount Δ _1o of the first link 101A into an estimated deformation amount _ΔθL1 of the first joint JTAA1 using equation 19.

(Variation 2)
This modification differs from the embodiment in that the first robot arm 100B has three joints. Below, this modification will be described focusing on the differences from the embodiment and modification 1, and descriptions of the same points as the embodiment and modification 1 will be omitted as appropriate.

Figure 7 is a side view modeling the configuration of robot 1B according to modified example 2. As shown in Figure 7, robot 1B includes second robot arm 200 similar to that of the embodiment, and first robot arm 100B. First robot arm 100B includes links 101B, 102B, 103B, and 104B, and joints JTAB1, JTAB2, and JTAB3. Although not limited thereto, links 101B and 102B of this modified example have the same configuration as links 101 and 102 of the embodiment, respectively, and fourth link 104B of this modified example has the same configuration as third link 103 of the embodiment. Joints JTAB1 and JTAB2 of this modified example have the same configuration as joints JTA1 and JTA2 of the embodiment, respectively.

One end of the third link 103B of this modified example is connected to the second link 102B by a third joint JTAB3. The second robot arm 200 is attached to the other end of the third link 103B of this modified example, similar to the second link 102 of the embodiment. The third joint JTAB3 is rotatable around a third axis S3 extending in a direction perpendicular to the support surface S. The directions of the first axis S1, the second axis S2, and the third axis S3 may be any direction, and may be different or the same as each other. The robot 1B is equipped with a control device 300 including an information processing device 300A and a robot controller 300B, which are the same as those of the embodiment. The information processing device 300A performs the same processing as the embodiment, but performs calculations using an arithmetic expression that differs from that of the embodiment in the following respects.

The inertial element estimation unit 409 uses Equation 1 to calculate the inertial characteristics L _1o , L _2o and L _3o of the links 101B, 102B and 103B, respectively.

The inertia force estimating unit 410 uses Equation 3 to calculate the joint screws M _1o , M _2o and M _3o of the joints JTAB1, JTAB2 and JTAB3, respectively.

The inertial force estimation unit 410 uses the following equations 22 to ³⁰ instead of equations 6 to 9 in the embodiment to calculate joint-induced inertial forces F _{11o, F 12o} , F _{13o, F 21o, F 22o, F 23o, F 31o, F 32o, and F 33o generated in the links 101B, 102B, and 103B by the estimated accelerations θ 1'', θ 12' ' , and θ 3} ^' _{' of} ^the joints JTAB1, _JTAB2 , and _{JTAB3 ,} respectively. In this calculation, the inertial force estimation unit 410 uses the estimated accelerations θ ₁ ^'' , θ ₁₂ ^'' , and θ ₃ ^'' , respectively, of the joints JTAB1, JTAB2, and JTAB3, the inertial characteristics L _1o , L _2o , and L _3o , respectively, of the links 101B, 102B, and 103B, the inertial characteristic L _ao of the second robot arm 200, and the joint screws M _1o , M _2o, and M _3o , respectively, of the joints JTAB1, JTAB2, and JTAB3.

The third estimator 405 uses the following equations 31 to 33 instead of equations 10 and 11 in the embodiment to calculate estimated inertial forces F _1o , F _2o and F _3o generated in the links 101B, 102B and 103B, respectively.

The fourth estimator 406 uses the following equations 34 to 36 instead of equations 12 and 13 in the embodiment to calculate estimated torques τ ₁ , τ ₂ and τ ₃ acting on the joints JTAB1, JTAB2 and JTAB3, respectively.

The fourth estimator 406 calculates the estimated deformation amounts Δθ ₁ , Δθ ₂ and Δθ ₃ of the joints JTAB1, JTAB2 and JTAB3, respectively, by using the following equations 37 to 39 instead of equations 15 and 16 in the embodiment. In this calculation, the fourth estimator 406 uses the stiffnesses k _g1 , k _g2 and k _g3 of the joints JTAB1, JTAB2 and JTAB3, respectively.

The fourth estimator 406 calculates the estimated deformation amounts Δ _{1o , Δ 2o , and Δ 3o of the links 101B, 102B, and 103B, respectively, by using the following equations 40 to 42, instead of the equations 17 and 18 in the embodiment. In this calculation, the fourth estimator 406 uses the compliances C I1o , C I2o , and C I3o} of the links 101B, 102B, and 103B, respectively.

The fourth estimator 406 uses Equation 19 to convert the estimated deformation amounts Δ _1o , Δ _2o , and Δ _3o of the links 101B, 102B, and 103B into estimated deformation amounts ΔθL ₁ , ΔθL _{2 ,} and ΔθL ₃ of the joints JTAB1, JTAB2, and JTAB3.

Other Embodiments
Although the embodiment and the modified examples of the present disclosure have been described above, the present disclosure is not limited to the above embodiment and modified examples. In other words, various modifications and improvements are possible within the scope of the present disclosure. For example, the embodiment and modified examples to which various modifications have been applied, and forms constructed by combining components in different embodiments and modified examples are also included within the scope of the present disclosure.

For example, in the embodiments and modifications, the number of joints in the first robot arm is 1, 2, or 3, but the number of joints in the first robot arm may be 4 or more. In this case, the control device 300 can perform the same control as in the embodiments and modifications.

In addition, in the embodiment and the modified example, the degree of freedom of the joints of the first robot arm and the second robot arm is one, but this is not limited to this. Even if the degree of freedom of the joints of the first robot arm and the second robot arm is two or more, the control device 300 can perform the same control as in the embodiment and the modified example.

In addition, in the embodiment and the modified example, a case is exemplified in which the robot 1 performs the task of holding an object W, but regardless of the task that the robot 1 performs, the control device 300 can perform the same control as in the embodiment and the modified example.

Examples of each aspect of the technology of the present disclosure are given below. A control device according to one aspect of the present disclosure is a control device for a first robot arm having at least two links supporting a second robot arm and at least one joint connecting the at least two links to each other, comprising a first estimation unit that acquires a first operation command for causing the first robot arm to perform a first target operation, which is a target operation, and estimates the operation of the at least one joint when the first robot arm operates in accordance with the first operation command, and a second operation command for causing the second robot arm to perform a second target operation, which is a target operation, and estimates the operation of the at least one joint when the second robot arm operates in accordance with the second operation command, and a connection portion between the second robot arm and the link. a second estimation unit that estimates a force that the link receives from the second robot arm; a third estimation unit that estimates a force that the link receives based on the movement of the at least one joint estimated by the first estimation unit and the force estimated by the second estimation unit; a fourth estimation unit that estimates at least one of the deformation amount of the link and the deformation amount of the at least one joint based on the force estimated by the third estimation unit; and a correction command unit that generates a correction command for the first movement command to compensate for the deformation amount so as to move the connection part according to the first target movement based on the deformation amount estimated by the fourth estimation unit, and issues the correction command to the first robot arm.

According to the above aspect, the control device estimates the amount of deformation occurring in the link and/or joint of the first robot arm when the first robot arm executes the first target motion and the second robot arm executes the second target motion. The amount of deformation may cause a difference between the actual motion of the connection part according to the first motion command and the first target motion. The control device can cause the first robot arm to perform a motion that reduces the difference, that is, a motion that compensates for the amount of deformation, by issuing a correction command to the first robot arm. Thus, the control device can prevent the connection part from being unintentionally displaced from the target position and from being unintentionally oscillated due to the deformation of the link and/or the deformation of the joint. Thus, unintentional fluctuations in the position of the connection part, which is the base of the second robot arm, are suppressed.

In a control device according to one aspect of the present disclosure, the at least two links include a base end link and a first link connected to the base end link and the second robot arm, the at least one joint includes a first joint connecting the first link to the base end link, the first estimator estimates the movement of the first joint, the third estimator estimates the force acting on the first link based on the movement of the first joint estimated by the first estimator and the force estimated by the second estimator, and the fourth estimator may estimate at least one of the deformation amount of the first link and the deformation amount of the first joint based on the force acting on the first link estimated by the third estimator.

According to the above aspect, the control device can control a first robot arm having one joint and suppress unintended fluctuations in the position of the base of the second robot arm.

In a control device according to one aspect of the present disclosure, the at least two links include a base end link, a first link connected to the base end link, and a second link connected to the second robot arm, the at least one joint includes a first joint connecting the first link to the base end link and a second joint connecting the second link to the first link, the first estimator estimates the movements of the first joint and the second joint, and the third estimator estimates the movements of the first joint and the second joint based on the movements of the first joint and the second joint estimated by the first estimator and the force estimated by the second estimator. The third estimation unit estimates the force that the second link receives based on the movements of the first joint and the second joint estimated by the first estimation unit and the force estimated by the second estimation unit, the fourth estimation unit estimates at least one of the deformation amount of the first link and the deformation amount of the first joint based on the force that the first link receives estimated by the third estimation unit, and the fourth estimation unit may estimate at least one of the deformation amount of the second link and the deformation amount of the second joint based on the force that the second link receives estimated by the third estimation unit.

According to the above aspect, the control device controls a first robot arm having two joints, and can suppress unintended fluctuations in the position of the base of the second robot arm. The control device uses all of the estimated movements of the first joint and the second joint to estimate the forces acting on the first link and the second link, respectively. This improves the accuracy of estimating the forces acting on each link, thereby improving the accuracy of estimating the amount of deformation of each link and each joint.

The control device according to one aspect of the present disclosure may further include an inertial force estimation unit that estimates an inertial force generated in the link due to the movement of the at least one joint based on the movement of the at least one joint estimated by the first estimation unit, and the third estimation unit may estimate a force that the link receives based on the inertial force estimated by the inertial force estimation unit and the force estimated by the second estimation unit.

According to the above aspect, the control device estimates the inertial force of the link generated due to the movement of the joint, and estimates the force acting on the link using the estimated inertial force of the link. This improves the accuracy of estimating the force acting on the link.

The control device according to one aspect of the present disclosure further includes a first position estimation unit that estimates the position of the link, a second position estimation unit that estimates the position of the connection part, and an inertial element estimation unit that estimates the inertial characteristics of the link and the inertial characteristics of the second robot arm, the inertial characteristics of the link include the inertial moment and mass of the link as elements, the inertial characteristics of the second robot arm include the inertial moment and mass of the second robot arm as elements, the inertial force estimation unit estimates the inertial force generated in the link using the inertial characteristics of the link and the inertial characteristics of the second robot arm, the acceleration of the at least one joint, and a joint screw of the at least one joint, and the joint screw may be a feature indicating the state of the at least one joint including an element indicating the orientation of the at least one joint.

According to the above aspect, the inertial characteristics include a moment of inertia element and a mass element. The control device uses the inertial characteristics of the link and the second robot arm to estimate the inertial force generated in the link due to the movement of the joint. This improves the accuracy of estimating the inertial force.

A robot according to an embodiment of the present disclosure includes a control device according to an embodiment of the present disclosure, the first robot arm, and the second robot arm. According to the above embodiment, the same effect as the control device according to an embodiment of the present disclosure can be obtained. The robot can cause the first robot arm and the second robot arm to perform a target motion while suppressing unintended fluctuations in the position of the base of the second robot arm.

In a robot according to one aspect of the present disclosure, the control device may be configured to generate the first operation command and the second operation command and control the operation of the first robot arm and the second robot arm. According to the above aspect, the control device can function as a robot controller. In other words, the robot controller can cause the first robot arm and the second robot arm to perform a target operation while suppressing unintended fluctuations in the position of the base of the second robot arm.

In addition, all of the ordinal numbers, quantities, and other numbers used above are provided as examples to specifically explain the technology of the present disclosure, and the present disclosure is not limited to the exemplified numbers. In addition, the connection relationships between the components are provided as examples to specifically explain the technology of the present disclosure, and the connection relationships that realize the functions of the present disclosure are not limited to these.

The division of blocks in the functional block diagram is just one example, and multiple blocks may be realized as one block, one block may be divided into multiple blocks, and/or some functions may be transferred to other blocks. Furthermore, the functions of multiple blocks having similar functions may be processed in parallel or in a time-shared manner by a single piece of hardware or software.

1, 1A, 1B Robot 100, 100A, 100B First robot arm 101, 101A, 101B First link 102, 102A, 102B Second link 103 Link (base end link)
103B third link 104B fourth link (base end link)
110 Connection part (interface)
200 Second robot arm 300 Control device 300A Information processing device 300B Robot controller 403 First estimation unit 404 Second estimation unit 405 Third estimation unit 406 Fourth estimation unit 407 First position estimation unit 408 Second position estimation unit 409 Inertial element estimation unit 410 Inertial force estimation unit 411 Correction command unit JTA1, JTAA1, JTAB1 First joint JTA2, JTAB2 Second joint JTAB3 Third joint

Claims (7)

A control device for a first robot arm having at least two links supporting a second robot arm and at least one joint interconnecting the at least two links, comprising:
a first estimation unit that acquires a first movement command for causing the first robot arm to perform a first target movement that is a target movement, and estimates a movement of the at least one joint when the first robot arm moves in accordance with the first movement command;
a second estimation unit that acquires a second operation command for causing the second robot arm to perform a second target operation that is a target operation, and estimates a force that is applied from the second robot arm to a connection portion between the second robot arm and the link when the second robot arm operates in accordance with the second operation command;
an inertial force estimator that estimates an inertial force generated in the link due to movement of the at least one joint, based on the movement of the at least one joint estimated by the first estimator;
a third estimation unit that estimates a force acting on the link based on the inertial force estimated by the inertial force estimation unit and the force estimated by the second estimation unit;
a fourth estimator that estimates at least one of a deformation amount of the link and a deformation amount of the at least one joint based on the force estimated by the third estimator;
a correction command unit that generates a correction command for the first movement command to compensate for the amount of deformation so as to move the connection portion in accordance with the first target movement, based on the amount of deformation estimated by the fourth estimator, and issues the correction command to the first robot arm. the at least two links include a base end link and a first link connected to the base end link and the second robot arm;
the at least one joint includes a first joint connecting the first link to the base link;
The first estimator estimates a motion of the first joint,
the inertial force estimator estimates, based on the movement of the first joint estimated by the first estimator, a force of inertia generated in the first link due to the movement of the first joint;
the third estimation unit estimates a force acting on the first link based on the inertial force acting on the first link estimated by the inertial force estimation unit and the force estimated by the second estimation unit;
The control device according to claim 1 , wherein the fourth estimator estimates at least one of a deformation amount of the first link and a deformation amount of the first joint based on the force acting on the first link estimated by the third estimator. the at least two links include a base end link, a first link connected to the base end link, and a second link connected to the second robot arm;
the at least one joint includes a first joint connecting the first link to the base link and a second joint connecting the second link to the first link;
The first estimator estimates movements of the first joint and the second joint,
the inertial force estimator estimates, based on the movements of the first joint and the second joint estimated by the first estimator, inertial forces generated in the first link and the second link due to movements of the first joint and the second joint;
the third estimation unit estimates a force acting on the first link based on the inertial force acting on the first link estimated by the inertial force estimation unit and the force estimated by the second estimation unit;
the third estimation unit estimates a force acting on the second link based on the inertial force occurring in the second link estimated by the inertial force estimation unit and the force estimated by the second estimation unit;
the fourth estimator estimates at least one of a deformation amount of the first link and a deformation amount of the first joint based on the force acting on the first link estimated by the third estimator;
The control device according to claim 1 , wherein the fourth estimator estimates at least one of a deformation amount of the second link and a deformation amount of the second joint based on the force acting on the second link estimated by the third estimator. a first position estimation unit that estimates a position of the link;
A second position estimation unit that estimates a position of the connection portion;
an inertial element estimator that estimates an inertial characteristic of the link and an inertial characteristic of the second robot arm,
The inertial characteristics of the link include a moment of inertia and a mass of the link;
The inertial characteristics of the second robot arm include a moment of inertia and a mass of the second robot arm as elements;
the inertial force estimator estimates the inertial force generated in the link by using an inertial characteristic of the link, an inertial characteristic of the second robot arm, an acceleration of the at least one joint, and a joint screw of the at least one joint;
A control device according to any one of claims 1 to 3, wherein the joint screw is a feature indicative of a state of the at least one joint, the feature including an element indicative of an orientation of the at least one joint. A control device according to any one of claims 1 to 4 ;
The first robot arm;
The robot comprises the second robot arm. The robot of claim 5 , wherein the control device is configured to generate the first movement command and the second movement command to control the movement of the first robot arm and the second robot arm. 1. A method for controlling a first robot arm having at least two links supporting a second robot arm and at least one joint interconnecting the at least two links, comprising:
Obtaining a first motion command for causing the first robot arm to perform a first target motion that is a target motion;
Estimating an estimated joint motion, which is a motion of the at least one joint when the first robot arm moves in accordance with the first motion command;
Obtaining a second movement command for causing the second robot arm to perform a second target movement that is a target movement;
estimating an estimated connection part force, which is a force that a connection part between the second robot arm and the link receives from the second robot arm when the second robot arm operates in accordance with the second movement command;
estimating an estimated inertial force, which is an inertial force generated in the link due to the motion of the at least one joint, based on the estimated joint motion;
estimating an estimated link force, which is a force acting on the link, based on the estimated inertial force and the estimated connection portion force;
estimating an estimated deformation amount including at least one of a deformation amount of the link and a deformation amount of the at least one joint based on the estimated link force;
generating a correction command for the first motion command to compensate for the estimated deformation amount based on the estimated deformation amount so as to move the connection portion in accordance with the first target motion;
and issuing the correction command to the first robot arm.
Control methods.

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