JP2017030059A - Robot control device, robot and robot system - Google Patents

Abstract

Provided is a technique capable of controlling a manipulator based on a force acting on an appropriate position. A robot control apparatus according to the present invention is a robot control apparatus that controls a robot including a manipulator, a drive unit that drives the manipulator, and a force detector, and the drive unit according to a control parameter. A drive control unit that performs force control for controlling the control parameter, a reception unit that receives input of the control parameter, and an output waveform of the force detector that is obtained according to driving of the drive unit by the control parameter, and the control parameter And a display unit for displaying at the same time. [Selection] Figure 7

Description

  The present invention relates to a robot control device, a robot, and a robot system.

  A robot control device that controls a robot by adding a force detected by a force sensor attached to a wrist of the robot to a target force is known (see Patent Document 1).

US Pat. No. 7,340,323

However, although the force sensor of Patent Document 1 can detect the force acting on the wrist of the robot, there is a problem that the force acting on the target work on which the robot actually performs the work such as fitting cannot be detected. there were. For example, when the force acting on the wrist of the robot is smaller than the force acting on the workpiece, if the robot is controlled based on the force acting on the wrist of the robot, an excessive force acts on the workpiece. There was a problem of damaging the workpiece. The force acting on the wrist and workpiece of the robot can be optimized by adjusting control parameters in force control. However, there is a problem that it is difficult to predict what force will be applied if the control parameter is changed, and the control parameter for force control cannot be easily set.
The present invention has been created to solve the above-described problem, and an object of the present invention is to provide a technique capable of easily setting control parameters for force control.

  A robot control apparatus for achieving the above object is a robot control apparatus that controls a robot including a manipulator, a drive unit that drives the manipulator, and a force detector, and controls the drive unit according to control parameters. A drive control unit that performs force control, a reception unit that receives an input of a control parameter, a display unit that displays an output waveform of a force detector obtained according to driving of the drive unit by the control parameter simultaneously with the control parameter, and .

  In the above configuration, since the output waveform of the force detector obtained according to the drive of the drive unit by the control parameter and the control parameter are displayed at the same time, the control parameter can be easily set to obtain a desired output waveform. .

  Note that the function of each means described in the claims is realized by hardware resources whose function is specified by the configuration itself, hardware resources whose function is specified by a program, or a combination thereof. The functions of these means are not limited to those realized by hardware resources that are physically independent of each other.

It is a schematic diagram of a robot system. It is a block diagram of a robot system. It is a perspective view of an arm. It is a perspective view of an end effector. It is a perspective view of an end effector. It is a flowchart of a teaching process. It is a figure which shows GUI. It is a figure which shows GUI.

Hereinafter, embodiments of the present invention will be described in the following order with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the corresponding component in each figure, and the overlapping description is abbreviate | omitted.
(1) Robot system configuration:
(1-1) Robot and control terminal:
(1-2) Teaching terminal:
(2) Other embodiments:

(1) Robot system configuration:
As shown in FIG. 1, the robot system as the first embodiment of the present invention includes a robot 1, an end effector 2, a control terminal 3 (controller), and a teaching terminal 4 (teaching pendant). . The control terminal 3 and the teaching terminal 4 constitute a robot control device of the present invention. Each of the control terminal 3 and the teaching terminal 4 may be a dedicated computer or a general-purpose computer in which a program for the robot 1 is installed. Furthermore, the control terminal 3 and the teaching terminal 4 may not be separate computers but may be a single computer.

(1-1) Robot and control terminal:
The robot 1 is a single arm robot including one manipulator M, and the manipulator M includes an arm A and an end effector 2. The arm A includes six joints J1 to J6. Six arm members A1 to A6 are connected by joints J1 to J6. Joints J2, J3, and J5 are bending joints, and joints J1, J4, and J6 are torsional joints. The force sensor FS and the end effector 2 are attached to the most distal arm member A6 of the arm A through the joint J6. The end effector 2 grips the workpiece W with a gripper. A predetermined position of the end effector 2 is represented as TCP (Tool Center Point). The position of the TCP is a reference for the position of the end effector 2. The force sensor FS is a 6-axis force detector.

  A coordinate system that defines the space in which the robot 1 is installed is referred to as a robot coordinate system. In the present embodiment, the robot coordinate system is a three-dimensional orthogonal coordinate system defined by an X axis and a Y axis that are orthogonal to each other on a horizontal plane, and a Z axis that has a vertically upward direction as a positive direction. A rotation angle around the X axis is represented by RX, a rotation angle around the Y axis is represented by RY, and a rotation angle around the Z axis is represented by RZ. An arbitrary position in the three-dimensional space can be expressed by a position in the X, Y, and Z directions, and an arbitrary posture (rotation direction) in the three-dimensional space can be expressed by a rotation angle in the RX, RY, and RZ directions. Hereinafter, unless otherwise indicated, when it is expressed as a position, it can also mean a posture. Unless otherwise indicated, when expressed as force, it can also mean torque acting in the RX, RY, and RZ directions. The controller 3 controls the position of the TCP in the robot coordinate system by driving the arm A.

  FIG. 2 is a block diagram of the robot system. A control program for controlling the robot 1 is installed in the control device 3. The control device 3 includes a computer including a processor, RAM, and ROM. When the computer executes a control program recorded on a recording medium such as a ROM, the control device 3 includes a drive control unit 31 and a force conversion unit 32 as functional configurations. The drive control unit 31 and the force conversion unit 32 have a functional configuration realized by cooperation of hardware resources and software resources of the control device 3. Note that the drive control unit 31 and the force conversion unit 32 are not necessarily realized by software resources, and may be realized by an ASIC (Application Specific Integrated Circuit).

  The drive control unit 31 performs position control and force control of the manipulator M. Specifically, the drive control unit 31 controls the position of the arm A so that the TCP position approaches the target position. The drive control unit 31 controls the force of the arm A so that the acting force acting on the CCP (Compliance Center Point) approaches the target force.

  FIG. 3 is a perspective view of the manipulator M, and FIG. 4 is a perspective view of the end effector 2. The CCP is a position that can be arbitrarily set on a grasped object such as the end effector 2 or the workpiece W. The CCP is preferably provided at a position where the CCP is to come into contact with another object among the positions on the end effector 2 and the workpiece W. The CCP shown in FIG. 4 is set at a position that first contacts the member to be fitted in the workpiece W that is a fitting member. When the end effector 2 or the workpiece W makes point contact with another object, the position of the contact point may be set to CCP. When the end effector 2 or the workpiece W is in line contact with another object, the position on the contact line (for example, the position of the middle point) may be set to CCP. When the end effector 2 or the workpiece W is in surface contact with another object, the position on the contact surface (for example, the position of the center of gravity) may be set to CCP.

  For example, when the gripping object is gripped by the gripper of the end effector 2, the CCP may be set at a position on the gripper that contacts the gripping object. Further, when the tip tool included in the end effector 2 processes the workpiece, the CCP may be set at a position on the tip tool that contacts the workpiece. For example, when a workpiece is processed by a gripping object gripped by the end effector 2 or a gripping object is assembled to an assembly target, the position on the gripping target that contacts the processing target or the assembly target CCP may be set in The target force is a force to be applied to the CCP and is a force arbitrarily set in the robot coordinate system.

In the description of the drive control unit 31, the letter S represents any one of the axis directions (X, Y, Z, RX, RY, RZ) that define the robot coordinate system. For example, in the case of S = X, X-direction component of the position specified in the robot coordinate system is denoted as S _t = X _t, X-direction component of the desired force is denoted as f _St = f _Xt. S represents the position in the S direction (rotation angle).

The robot 1 includes motors M1 to M6 as drive units and encoders E1 to E6 in addition to the configuration illustrated in FIG. The motor M1-M6 and encoders E1 to E6, and provided corresponding to each of the joints J1 to J6, encoders E1 to E6 detects the drive position D _a of the motor M1-M6. Controlling the arm A means controlling the motors M1 to M6 as drive units. The drive control unit 31 can communicate with the robot 1. Drive control unit 31 stores the rotation angle of each joint J1~J6 derived from the drive position D _a of the motor M1-M6, the conversion relation U for converting the position of the TCP in the robot coordinate system to each other . The conversion relationship U is a function obtained based on forward kinematics and inverse kinematics, and may include, for example, a simultaneous conversion matrix. Drive control unit 31, the conversion relation U, from the driving position D _a motor M1~M6 can derive the position of the TCP, it is also possible to derive the drive position D _a motor M1~M6 from the position of the TCP reversed.

The force conversion unit 32 converts the detection force f ₀ into an acting force that is a force acting on the CCP arbitrarily set on the manipulator M or on the grasped object gripped by the manipulator M. As shown in FIG. 4, the force sensor FS is a force F _FSO (F _FSOα , F _FSOβ , F _FSOγ ) which is a force in three α, β and γ axial directions orthogonal to each other in an FSO (Force Sensor Origin). _Then , the detection force f ₀ composed of the torques M _FSO (M _FSOα , M _FSOβ , M _FSOγ ) around the three detection axes is detected. The FSO exists on the central axis of the cylindrical force sensor FS. The detection force f ₀ means an actual force acting on the FSO. The coordinate system and sensor coordinate system are described with the FSO as the origin and the detection axes (α, β, γ axes) as the coordinate axes. Further, a coordinate system having TCP as the origin and an axis in the same direction as the detection axis as a coordinate axis is referred to as a tool coordinate system. The direction of the coordinate axis of the sensor coordinate system may be different from the direction of the detection axis, but is assumed to be the same for simplicity of explanation.

Power converter 32, based on the driving position D _a motor M1~M6 and conversion relation U, to derive the direction of the coordinate axes of the sensor coordinate system in the robot coordinate system (= the direction of the coordinate axes of the tool coordinate system). As a result, it is possible to grasp the direction in which the detection force f ₀ detected by the force sensor FS is directed in the robot coordinate system. When the direction of the coordinate axis of the sensor coordinate system is different from the direction of the coordinate axis of the tool coordinate system, the force conversion unit 32 derives the direction of the coordinate axis of the sensor coordinate system by rotationally converting the direction of the coordinate axis of the tool coordinate system. do it.

The force conversion unit 32 _derives the force F _CCP (F _CCPα , F _CCPβ , F _CCPγ ) acting on the CCP based on the force F _FSO (F _FSOα , F _FSOβ , F _FSOγ ) acting on the _FSO . In the present embodiment, the force sensor FS, the end effector 2 and the workpiece W are assumed to be an integral rigid body. Therefore, the force conversion unit 32 derives the force F _FSO in the _FSO as it is as the force F _CCP in the CCP. The force F _FSO (F _FSOα , F _FSOβ , F _FSOγ ) acting on the FSO and the force F _CCP (F _CCPα , F _CCPβ , F _CCPγ ) acting on the _CCP are not necessarily the same. For example, when the direction of the axis of the sensor coordinate system that defines the force F _FSO acting on the FSO is different from the direction of the axis of the coordinate system that defines the force F _CCP acting on the CCP, the force conversion unit 32 The force F _CCP acting on the CCP may be derived by rotationally converting the force F _FSO acting on the CCP. For example, when the end effector 2 is tilted with respect to the force sensor FS, the direction of the axis of the sensor coordinate system that defines the force F _FSO acting on the _FSO and the force F _CCP acting on the _CCP The direction of the axes of the coordinate system that defines can be different.

The force converter 32 is based on the force F _FSO (F _FSOα , F _FSOβ , F _FSOγ ) acting on the _FSO and the torque M _FSO ( _MFSOα , M _FSOβ , M _FSOγ ), and the torque M _FSO (M _CCPα , M _CCPβ , M _CCPγ ) are derived. FIG. 5 is a perspective view showing how torque M _CCP (M _CCPα , M _CCPβ , M _CCPγ ) acting on _CCP is derived. The CCP coordinates (α _CCP , β _CCP , γ _CCP ) in the sensor coordinate system are known and recorded on the recording medium. As shown in FIG. 5, a vector extending from FSO to CCP is expressed as a vector P _CCP (α _CCP , β _CCP , γ _CCP ). The force converter 32 derives the torque M _CCP acting on the CCP by the following equation (1).
As shown in the above equation (1), the torque M _CCP acting on the _CCP is derived by subtracting the outer product of the vector P _CCP and the force _FFSO acting on the _FSO from the torque MFSO acting on the _FSO. The

Cross product of the force F _FSO acting on vector P _CCP and the FSO, the magnitude of the vector P _CCP (Distance from FSO to CCP), are those obtained by multiplying the force F _FSO acting on FSO, acting FSO The force F _FSO means the torque generated in the FSO. By the above calculation, the force conversion unit 32 can _derive the acting force f _S (F _CCPα , F _CCPβ , F _CCPγ , M _CCPα , M _CCPβ , M _CCPγ ) acting on the CCP. Further, the force conversion unit 32 derives the acting force f _S in the robot coordinate system by rotationally transforming the acting force f _S based on the directions of the α, β, and γ axes in the robot coordinate system.

Further, the force conversion unit 32 performs gravity compensation for the acting force f _S. Gravity compensation is to remove the gravity component from the acting force f _S. The acting force f _S subjected to gravity compensation can be regarded as a force other than gravity acting on the CCP. The gravity component of the acting force f _S acting on the CCP is investigated in advance for each TCP (CCP) posture, and the drive control unit 31 subtracts the gravity component corresponding to the TCP posture from the acting force f _S. Gravity compensation is realized. Note that gravity compensation does not necessarily have to be performed, and may be omitted depending on the content of the work.

The drive control unit 31 specifies the force-derived correction amount ΔS by substituting the target force f _St and the acting force f _S into the equation of motion for impedance control. Equation (2) is an equation of motion for impedance control.
The left side of the equation (2) is a first term obtained by multiplying the second-order differential value of the TCP position S by the virtual inertia coefficient m, a second term obtained by multiplying the differential value of the TCP position S by the virtual viscosity coefficient d, And a third term obtained by multiplying the position S of the TCP by the virtual elastic coefficient k. The right side of the equation (2) is constituted by a force deviation Δf _S (t) obtained by subtracting the actual acting force f _S from the target force f _St. The differentiation in the equation (2) means differentiation with time. In the step of the robot 1 performs, to sometimes fixed value as the target force f _St is set, there is a case where the value derived by a function that depends on time as the target force f _St is set.

The impedance control is control for realizing a virtual mechanical impedance by the motors M1 to M6. The virtual inertia coefficient m means the mass that the TCP virtually has, the virtual viscosity coefficient d means the viscous resistance that the TCP virtually receives, and the virtual elastic coefficient k is the spring constant of the elastic force that the TCP virtually receives. means. Each coefficient m, d, k may be set to a different value for each direction, or may be set to a common value regardless of the direction. The force-derived correction amount ΔS means the size of the position S where the TCP should move in order to eliminate the force deviation Δf _S (t) from the target force f _St when the TCP receives mechanical impedance. To do. Drive control unit 31, the target position S _t, by adding a force from the correction amount [Delta] S, identifies the correction target position in consideration of the impedance control (S _t + ΔS).

Then, based on the conversion relationship U, the drive control unit 31 sets the corrected target position (S _t + ΔS) in the direction of each axis that defines the robot coordinate system as the target drive position that is the target drive position of each motor M1 to M6. into a position D _t. Then, the drive control unit 31, by the target drive position D _t subtracting the actual drive position D _a of the motor M1-M6, calculates the driving position deviation _{D e (= D t -D a} ). Drive control unit 31, a value obtained by multiplying the position control gain K _p to the driving position deviation D _e, the driving speed deviation which is a difference between the driving speed is the time differential value of the actual drive position D _a, the speed control gain The control amount D _c is specified by adding the value multiplied by K _v . Note that the position control gain K _p and the speed control gain K _v may include not only a proportional component but also a control gain related to a differential component and an integral component. The control amount D _c is specified for each of the motors M1 to M6. With the configuration described above, the drive control unit 31 may control the arm A on the basis of the target position S _t and the target force f _St.

(1-2) Teaching terminal:
The teaching terminal 4, teaching program for teaching a target position S _t and the target force f _St to the control terminal 3 is installed. The teaching terminal 4 includes a processor, a RAM, and a ROM, and these hardware resources cooperate with the control program. Thereby, as shown in FIG. 2, the teaching terminal 4 as a setting part will be provided with the 1st display part 41, the 2nd display part 42, and the reception part 43 as a function structure. Although not shown, the teaching terminal 4 includes an input device (such as a mouse, a keyboard, and a touch panel) that receives instructions from the user, and a display device (display) that outputs various types of information to the user. Hereinafter, details of processing performed by the first display unit 41, the second display unit 42, and the reception unit 43 will be described with reference to flowcharts. The 1st display part 41 and the 2nd display part 42 comprise the display part of this invention.

FIG. 6 is a flowchart of the teaching process. Incidentally, the teaching process of Fig. 6 is a process for teaching the coefficient of impedance control with target forces f _St, and the process for teaching the target position S _t are separately performed. Target position S _t can be taught by a known teaching techniques, for example to the user a target position S _t by moving manually the arm A may be taught, specify the coordinates in the robot coordinate system at the teaching terminal 4 target position S _t may be taught by.

First, the receiving unit 43 moves the arm A to the operation start position (step S100). That is, the reception unit 43 causes the control terminal 3 to execute control of the arm A so that TCP is the operation start position. The operation start position is a TCP position immediately before the arm A is controlled so that the target force f _St acts on the CCP. For example, the position immediately before pressing the workpiece W held by the end effector 2 against another object, the position immediately before processing another object by the end effector 2 holding the processing tool, or the like. However, in the teaching process of FIG. 6, it is only necessary to set the target force f _St and the impedance control coefficient, and the operation start position necessarily controls the arm A so that the acting force f _S acts on the CCP in actual work. It may not be the position immediately before. Next, the reception unit 43 displays a GUI (graphical user interface) (step S110). The GUI is a setting screen of the present invention.

  FIG. 7 is a diagram showing a GUI. As shown in FIG. 7, the GUI includes input windows N1 to N3, a slider bar H, display windows Q1 and Q2, graphs G1 and G2, and buttons B1 and B2. The accepting unit 43 accepts an operation performed on the GUI by the input device.

When the GUI is displayed, the receiving unit 43 receives the direction of the force (the direction of the target force f _St ) and the magnitude of the force (the magnitude of the target force f _St ) (Step S120). In the GUI, an input window N1 for receiving the direction of force and an input window N2 for receiving the magnitude of force are provided. The receiving unit 43 receives an input in the direction of any axis that defines the robot coordinate system in the input window N1. Moreover, the reception part 43 receives the input of arbitrary numerical values in the input window N2.

  Next, the reception unit 43 receives a virtual elastic coefficient k (step S130). In the GUI, an input window N3 for receiving a virtual elastic coefficient k as the first set value is provided. The accepting unit 43 accepts input of an arbitrary numerical value in the input window N3. When the user wants to make the workpiece W or the end effector 2 softly contact other objects, the virtual elastic coefficient k may be set to a small value. On the other hand, when the user wants to make the workpiece W or the end effector 2 come into hard contact with another object, the virtual elastic coefficient k may be set to a large value.

When the virtual elastic coefficient k is received, the second display unit 42 displays the memory waveform V corresponding to the virtual elastic coefficient k on the graph G2 (step S140). The horizontal axis of the graph G2 indicates time, and the vertical axis of the graph G2 indicates the acting force f _S. The memory waveform V is a time response waveform of the acting force f _S and is stored in advance in the storage medium of the teaching terminal 4 for each virtual elastic coefficient k. The stored waveform V is a waveform that converges to a force having a magnitude received by the input window N. The memory waveform V is a time response waveform of the acting force f _S acting on the CCP when the arm A is controlled so that the force of the magnitude received in the input window N2 acts on the CCP under general conditions. is there. When the virtual elastic modulus k is different, the shape (inclination) of the memory waveform V is greatly different. Therefore, the memory waveform V is stored for each virtual elastic coefficient k.

  The stored waveform V may be a waveform that is a guideline for the user. For example, the waveform V may be a waveform recommended by the manufacturer of the robot 1 or a waveform that has been successfully used by the robot 1 in the past. Also good. Further, the memory waveform V may be prepared for each work content such as a fitting work and a polishing work, or the mechanical characteristics (elastic coefficient, hardness, etc.) of the work W, and the work W and the end effector 2 are in contact with each other. It may be prepared for each mechanical property of the object.

  Next, the reception unit 43 receives the virtual viscosity coefficient d and the virtual inertia coefficient m in accordance with the operation of the slider H1 on the slider bar H (step S150). In the GUI of FIG. 7, as a configuration for receiving the virtual inertia coefficient m and the virtual viscosity coefficient d, a slider bar H and a slider H1 that can slide on the slider bar H are provided. The accepting unit 43 accepts an operation of sliding the slider H1 on the slider bar H. Note that the slider bar H indicates that as the slider H1 moves to the right, the stability is set to be more important, and as the slider H1 moves to the left, the response is set to be more important.

  And the reception part 43 acquires the slide position of the slider H1 on the slider bar H, and receives the virtual inertia coefficient m and the virtual viscosity coefficient d corresponding to the said slide position. Specifically, the reception unit 43 sets the virtual inertia coefficient m as the second set value so that the ratio between the virtual inertia coefficient m and the virtual viscosity coefficient d is constant (for example, m: d = 1: 1000). The setting of the virtual viscosity coefficient d is accepted. In addition, the reception unit 43 displays the virtual inertia coefficient m and the virtual viscosity coefficient d corresponding to the slide position of the slider H1 on the display windows Q1 and Q2.

Note that the virtual inertia coefficient m and the virtual viscosity coefficient d increase as the slider H1 is moved to the right in the slider bar H of FIG. When the virtual inertia coefficient m and the virtual viscosity coefficient d are increased, the position of the TCP is difficult to move, so that the acting force f _S acting on the CCP is easily stabilized. When the virtual inertia coefficient m and the virtual viscosity coefficient d are reduced, the position of the TCP is easily moved, so that the responsiveness of the acting force f _S acting on the CCP is improved. The slider H1 corresponds to a single operation unit that can accept the setting of the virtual inertia coefficient m and the virtual viscosity coefficient d.

Next, the reception unit 43 controls the arm A with the current set value in accordance with the operation of the operation button B1 (step S160). That is, the accepting unit 43 outputs the target force f _St set by the GUI and the control parameters m, d, and k for impedance control to the control terminal 3 and moves the arm A based on these set values. Command to control. In the case of the GUI of FIG. 7, the workpiece W moves in the −Z direction, and the workpiece W comes into contact with another object in the −Z direction so that the acting force f _S having the magnitude set by the GUI acts on the CCP. Then, arm A is controlled.

Next, the second display unit 42 displays the action waveform L is a waveform of the action force f _S in the graph G1 (step S170). The action waveform L as the output waveform is a time response waveform of the action force f _S acting on the CCP shown in FIGS. 3 to 5, and may be a time response waveform of the force F _CCP acting on the CCP, It may be a time response waveform of the acting torque M _CCP . The second display unit 42 acquires the applied force f _S after gravity compensation from the control terminal 3 for each predetermined sampling period and stores it in the storage medium of the teaching terminal 4 during the period in which the arm A is controlled in step S160. Keep it. When step S160 ends, the acting force f _S for each sampling period is acquired from the storage medium, and the action waveform L, which is a time-series waveform of the acting force f _S , is displayed on the graph G1. The vertical axis and horizontal axis of the graph G1 are the same scale as the vertical axis and horizontal axis of the graph G2. Of course, the action waveform L is also a waveform that converges to a force of a magnitude received by the input window N.

  Next, the reception unit 43 determines whether or not the determination button B2 has been operated (Step S180). That is, the reception unit 43 determines whether an operation for deterministically setting each setting value set in the GUI has been received.

  If it is not determined that the enter button B2 has been operated (step S180: N), the accepting unit 43 accepts a change in the setting value through the GUI (step S190), and returns to step S160. That is, assuming that the user is not satisfied with the action waveform L, an operation for setting the control parameters m, d, and k for impedance control is subsequently accepted through the GUI. If the determination button B2 is operated after accepting the change of the set value, the arm A is controlled by the changed set value, and the action waveform L is updated and displayed on the graph G1. If the virtual elastic coefficient k is changed in step S190, the stored waveform V may be updated and displayed on the graph G2.

On the other hand, when it is determined that the determination button B2 has been operated (step S180: Y), the receiving unit 43 outputs the set value to the control terminal 3 (step S200), and ends the teaching process. Thereby, the control parameters m, d, and k for impedance control can be taught to the control terminal 3 together with the target force f _St set by the GUI.

  In the above configuration, the first display unit 41 and the second display unit 42 have an action waveform L as an output waveform of the force sensor FS obtained according to driving of the driving unit by the control parameters m, d, and k, The control parameters m, d, and k are displayed at the same time. Thereby, the control parameters m, d, and k can be easily set so as to obtain a desired action waveform L. Displaying the control parameters m, d, and k may be to display numerical values, to display the slider H1 whose position changes according to the numerical values, or to display a graph or the like. It may be. Displaying at the same time is not limited to displaying on a single screen, as long as it is displayed in a comparable manner. Further, the user can determine whether or not the actual action waveform L obtained by converting the detection force detected by the force sensor FS has a desired shape as compared with the storage waveform V stored in the storage medium in advance. The virtual inertia coefficient m and the virtual viscosity coefficient d can be set so that the action waveform L has a desired shape. Since the virtual inertia coefficient m and the virtual viscosity coefficient d can be set so that the action waveform L has a desired shape, it is possible to set the control with a high degree of freedom while considering the time response waveform. It is not always necessary for the user to set the virtual inertia coefficient m and the virtual viscosity coefficient d for obtaining the action waveform L having a shape similar to the memory waveform V. For example, the user converges faster or slower than the memory waveform V. It is possible to intentionally set the virtual inertia coefficient m and the virtual viscosity coefficient d from which an action waveform L that is obtained can be obtained. In addition, the user can intentionally set the virtual inertia coefficient m and the virtual viscosity coefficient d from which an action waveform L having an amplitude larger or smaller than the stored waveform V can be obtained.

  Further, since the memory waveform V corresponding to the virtual elastic coefficient k having a large influence on the time response waveform is displayed, the memory waveform V that is a reference in comparison with the action waveform L can be displayed. Further, since the virtual inertia coefficient m and the virtual viscosity coefficient d can be set by operating a single slider H1, the virtual inertia coefficient m and the virtual viscosity coefficient d can be easily set. Since the slider bar H indicates a direction in which stability is important and a direction in which responsiveness is important, the user can intuitively set the virtual inertia coefficient m and the virtual viscosity coefficient d. In particular, since the virtual inertia coefficient m and the virtual viscosity coefficient d maintain a constant ratio, settings that place importance on stability and settings that place importance on responsiveness can be easily realized.

In addition, the force conversion unit 32 converts the detection force detected by the force sensor FS into an action force f _S that is a force acting on the CCP. Therefore, the force conversion unit 32 applies not the detection force itself detected by the force sensor FS but the CCP. Force control can be performed so that the applied force f _{S, which} is the applied force, approaches the target force f _St. Therefore, by setting the CCP to an appropriate position, the manipulator M can be controlled based on the force acting on the appropriate position.

(2) Other Embodiments The robot 1 does not necessarily have to be a six-axis single-arm robot, and may be any robot that applies a force to any location as the robot is driven. For example, the robot 1 may be a double-arm robot or a scalar robot.

  Moreover, the control terminal 3 should just perform control based on the detection value of a force detector, a 1st setting value, and a 2nd setting value, and may perform force control other than impedance control. Moreover, the control terminal 3 does not necessarily need to perform impedance control considering all three parameters m, d, and k, and may perform impedance control considering one or two of them.

  The receiving unit 43 does not necessarily receive the setting of the virtual inertia coefficient m and the virtual viscosity coefficient d so that the ratio between the virtual inertia coefficient m and the virtual viscosity coefficient d is constant, and the position of the slider H1 The ratio between the virtual inertia coefficient m and the virtual viscosity coefficient d may be changed according to the operation status of other operation units. Furthermore, the reception unit 43 does not necessarily have to receive the virtual inertia coefficient m and the virtual viscosity coefficient d with a single operation unit (slider H1). A GUI that can be directly input to the coefficient d may be provided.

  In the configuration in which the stored waveform V corresponding to the first set value is displayed, the first set value is not necessarily the virtual elastic coefficient k, and is at least one of the virtual inertia coefficient m and the virtual viscosity coefficient d. Also good. Furthermore, the receiving unit 43 does not necessarily receive both the first set value and the second set value, and may receive at least the second set value. For example, the receiving unit 43 may display the stored waveform V corresponding to the predetermined virtual elastic coefficient k without receiving the virtual elastic coefficient k as the first set value.

As shown in FIG. 8, the GUI may be configured to represent the time response waveform Q of the detection force together with the time response waveform L of the acting force f _S. That is, the teaching terminal 4 not only displays the time response waveform L of the acting force f _S after the force conversion unit 32 converts, but also the time response waveform Q of the detection force before the force conversion unit 32 converts. A GUI that also includes a graph G3 for displaying may be displayed. Thereby, it can be easily determined whether or not an excessive force is applied to the force sensor FS, and the time response waveform L of the acting force f _S and the time response waveform Q of the detecting force can be compared. .

  Furthermore, in the embodiment, TCP and CCP are set at different positions, but TCP and CCP may be at the same position. That is, the position serving as a reference for position control and the position serving as a reference for force control may be the same position. Accordingly, the force acting on the TCP can be controlled while strictly controlling the position of the TCP (= CCP). For example, by setting TCP and CCP at the tip position of the tip tool, the tip position and force of the tip tool (driver, bit, etc.) can be controlled with high accuracy.

1 ... robot, 2 ... end effector, 3 ... control unit, 31 ... drive control unit, 32 ... force converter unit, A ... arm, A1 to A6 ... arm member, d ... virtual viscosity coefficient, D _a ... driving position, D _c ... control amount, D _e ... drive position deviation, D _t ... target drive position, E1 to E6 ... encoder, f _S ... acting force, f _S ... target force, FS ... force sensor, f _St ... target force, J1 ～J6 ... joint, K ... recess, k ... virtual modulus, K _p ... position control gain, K _v ... speed control gain, m ... virtual inertia coefficient, M1-M6 ... motor, W ... workpiece, Delta] f _S ... force error , ΔS: Force-derived correction amount

Claims (6)

A robot control device that controls a robot comprising a manipulator, a drive unit that drives the manipulator, and a force detector,
A drive control unit that performs force control for controlling the drive unit according to a control parameter;
A receiving unit that receives input of the control parameter;
A display unit for displaying an output waveform of the force detector obtained according to driving of the driving unit by the control parameter simultaneously with the control parameter;
A robot control device comprising: A force conversion unit that converts the detection force detected by the force detector into an acting force that is a force acting on a compliance center point that is arbitrarily set on the manipulator or on a grasped object grasped by the manipulator;
The display unit displays the waveform of the acting force as the output waveform;
The robot control apparatus according to claim 1. The drive control unit performs position control for controlling the drive unit so that the position of the tool center point set on the manipulator or on the gripping object gripped by the manipulator approaches a preset target position,
The compliance center point and the tool center point are at the same position.
The robot control apparatus according to claim 2. The display unit represents a time response waveform of a force stored in a storage medium in advance and a time response waveform of the acting force in a comparable manner.
The robot control apparatus according to any one of claims 1 to 3. The drive unit is controlled by the robot control device according to any one of claims 1 to 4.
robot. The robot control device according to any one of claims 1 to 4,
A robot whose drive unit is controlled by the robot control device;
A robot system comprising: