JP2011104740A - Force control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a force control device that prevents an excess force from exerting at the time of occurrence of a positional shift by changing force limit value and a compliance control parameter during operation while achieving high speed for the operation. <P>SOLUTION: Based on a command indicating parameter conditions including at least one of the force limit value of force exerting to a tip of a robot according to a work operation performed by the robot from a changing point designation means 5 and a force control parameter of the compliance control, and the changing point for changing into the parameter conditions, the force control device inputs a stop command outputting a position command to decelerate and stop the robot by a command generation means 1 that outputs the position command showing a target position of the robot according to the work operation performed by the robot when the parameter changing means 6 changes at least one of the force limit value and the force control parameter, and a determination means 4 for an excess force limit value determines that force exceeding the force limit value is exerted. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a force control device applied to a robot that performs assembly, deburring, polishing, substrate mounting, inspection, and the like, an automatic assembly apparatus, a mounting machine, a processing machine, and an inspection apparatus.

  For example, in this type of apparatus described in Patent Document 1 below, a force sensor is provided at the tip of a robot that takes out a part from a magazine storing the part, moves it to a predetermined position, and performs a part assembling operation. The robot controller performs compliance control by feedback of the force detected by the force sensor, compares the detected force with a preset force threshold, determines the next robot operation, and determines the success or failure of the work based on the comparison result. Is going. For example, when holding a round bar-shaped part with a hand and lowering it to insert it, if the force detected during insertion (descent) exceeds the threshold, the lowering operation is stopped because the insertion operation has failed. , Prevent the generation of excessive force. After stopping the hand, work again or generate an alarm.

Japanese Patent Laid-Open No. 7-24665

  There are many operations where the reaction force is small at the start of the operation, but the reaction force is large at the end of the operation, such as insertion of a connector or rubber hose. When such work is performed with one operation, in the conventional apparatus, it is necessary to set the compliance control parameter and the force threshold to values suitable for a large reaction force acting at the end of the work. For this reason, even if there is a misalignment at the start of work, it is necessary to set a threshold of force greater than necessary, so it is necessary to reduce the work speed to reduce the force generated at the time of misalignment, and the operation time There was a problem of becoming longer.

  Also, although it is determined whether the detected force exceeds a preset threshold, force information in a direction that does not exceed the threshold is not utilized, so it is not possible to stop due to a work error at the time of displacement However, no consideration was given to the subsequent recovery operation.

  The present invention has been made to solve the above-described problems, and by switching between a force threshold value (force limit value) and a compliance control parameter during operation, an excessive force is generated at the time of occurrence of misalignment while speeding up the work. It is an object of the present invention to provide a force control device that prevents the action of.

  The present invention provides a command for instructing a switching point for switching a parameter including at least one of a force limit value of a force acting on a robot tip and a force control parameter for compliance control according to a work operation to be performed by the robot from a switching point designating unit. Based on the above, when the parameter switching means switches at least one of the force limit value and the force control parameter, and the force limit excess determining means determines that a force exceeding the force limit value is acting, the work operation to be performed by the robot The force control device is characterized in that a stop command for outputting a position command for decelerating and stopping the robot is input to command generating means for outputting a position command indicating the target position of the robot.

  In the present invention, by switching the force threshold value (force limit value) and the compliance control parameter during the operation, it is possible to prevent an excessive force from acting when a positional deviation occurs while speeding up the operation.

It is a block diagram which shows the structure of the force control apparatus in Embodiment 1, 2 of this invention. It is a figure which shows an example of an internal structure of the robot control means of FIG. It is a figure which shows an example of the internal structure of each axis | shaft position control means of FIG. It is a figure which shows an example of the internal structure of the force sense consideration correction | amendment means of FIG. It is a figure which shows another example of the internal structure of the force sense consideration correction | amendment means of FIG. It is a figure which shows another example of the internal structure of the force sense consideration correction | amendment means of FIG. It is a figure which shows another example of the internal structure of the force sense consideration correction | amendment means of FIG. It is a block diagram which shows the structure of the force control apparatus in Embodiment 3 of this invention. It is a figure which shows an example of an internal structure of the force sense consideration correction | amendment means of FIG. It is a block diagram which shows the structure of the force control apparatus in Embodiment 4 of this invention. It is a block diagram which shows the structure of the force control apparatus in Embodiment 5-9 of this invention. It is a block diagram which shows the structure of the force control apparatus in Embodiment 10 of this invention. It is a block diagram which shows the structure of the force control apparatus in Embodiment 11 of this invention.

  Hereinafter, a force control device according to the present invention will be described with reference to the drawings according to each embodiment. In each embodiment, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
1 is a block diagram showing a configuration of a force control apparatus according to Embodiment 1 of the present invention. The command generation means 1 inputs, for example, a position command indicating the target position of the robot 3 every moment to the robot control means 2 based on a work operation program for work to be performed by the robot 3 stored in advance in the storage means M. The robot control means 2 performs follow-up control of the robot 3 in accordance with a given position command, a force control parameter for compliance control described later, and a feedback signal from the robot 3, for example.

  The robot 3 controlled by the robot control means 2 includes a single-axis or multi-axis motor (not shown). As an example, a 6-axis vertical articulated robot called an industrial robot and a 4-axis horizontal articulated robot. Etc. A force sensor for measuring the acting force and moment is attached to the vicinity of the tip of the robot 3 or the object on which the robot works (both are not shown), and the force and moment measured by the force sensor are the force. The detected value is input to the robot control means 2 and the force limit excess determination means 4.

  The force detection value is a force in three axes and a moment around each axis when a six-axis force sensor is used, and a force in three axes when a force sensor of five or less axes is used. Of the moments around each axis, these are measurable moments, and each force sensor transmits these data to the robot control means 2 and the force limit excess determination means 4. Further, a sensor for measuring the motor position of each axis such as an encoder or resolver is attached to the motor of each axis for driving the robot 3 (not shown), and the motor position of each axis measured by such a sensor is the robot control means. 2 is transmitted.

  The force limit excess determining means 4 compares the force threshold value (force limit value) input from the parameter switching means 6 with the force detection value transmitted from the force sensor of the robot 3, and at least one axial force or moment. When the force exceeds the force threshold value, a stop command is input to the command generating means 1. In this embodiment, the determination of exceeding the force limit is performed for each component of the detected force and moment, but may be performed for the combined force and moment. When the command generation means 1 receives a stop command from the force limit excess determination means 4, it generates a command to decelerate and stop from the current position / speed and inputs it to the robot control means 2.

  The switching point designating unit 5 sequentially designates the point where the parameter switching unit 6 switches the parameter and the parameter after switching in accordance with the operation of the work operation program. When there are two types of parameters to be switched by the parameter switching means 6, a force threshold and a force control parameter, for example, the following command is executed and specified in a robot program describing the operation of the robot 3.

  FCNT 30, 2

  Here, “FCNT” is a robot language (command) for designating a switching point, “30” designates starting parameter switching at a point 30% from the start of operation, and “2” after switching. Parameter condition number. For each condition number, a combination of a force threshold value and a force control parameter is recorded in the storage means M, for example, and the parameter switching means 6 is designated when the position command reaches the point set by the switching point designation means 5. The force threshold value and force control parameter corresponding to the condition number are read out.

  In FIG. 1, the command generation means 1 excluding the robot 3, the robot control means 2, the force limit excess determination means 4, the switching point designation means 5, and the parameter switching means 6 are configured by, for example, one computer (robot controller) and stored. A means M indicates a memory (including ROM, RAM, etc.) in the computer shared by each means.

  The parameter switching means 6 switches the force threshold immediately after passing the designated switching point. With respect to the force control parameter, switching is performed from the force control parameter before switching to the force control parameter after switching, for example, by output through a two-stage moving average filter. The switching point designated to start switching is set as the passage time. The force control parameter may be switched using a moving average filter of one stage or three or more stages, for example, a primary delay filter other than the moving average may be used. Further, a function for switching from the force control parameter before switching to the force control parameter after switching may be provided inside, and the switching may be performed gradually using the provided function. In this embodiment, the switching start point is specified by the ratio of the movement distance from the operation start point. However, the ratio of the movement distance to the operation end point, the movement distance from the operation start point, and the movement distance to the operation end point. Alternatively, it may be specified by an elapsed time from the start of the operation.

  An example of the internal configuration of the robot control means 2 is shown in FIG. The position command generated by the command generating unit 1 is corrected by adding the output of the force sense consideration correcting unit 7 by the adding unit K1. The inverse conversion means 8 performs an inverse conversion calculation for calculating the motor position of each axis that realizes the hand position / posture, and adds a position command corrected by adding the output of the force sense correction means 7 to the position of each axis of the robot. It is converted into a joint position command which is a command. The converted joint position command is input to each axis position control means 9. Each axis position control means 9 performs control so that the motor position of each axis follows the input joint position command.

  An example of the internal configuration of each axis position control means 9 is shown in FIG. In each axis position control unit 9n provided for each motor of each axis position control means 9 in FIG. 3, the subtractor G1 obtains the difference between the (joint) position command of each axis and the motor position of the axis, and the proportional unit 21 To enter. Then, the difference between the motor speed calculated by the subtraction unit G2 is obtained from the output of the proportional unit 21 and the differential value of the motor position obtained by the differentiation unit 23, and the obtained difference is input to the proportional integration unit 22. The control system has a configuration in which a speed proportional integration control system is provided in the position proportional control system, and is often used as a motor position control system.

  In this embodiment, the configuration of each axis position control unit 9n is a feedback control system that performs motor position control and speed control for each axis. However, the control system includes an observer for each axis. Alternatively, a control system including feedforward may be used. Moreover, it is not a configuration that is independent for each axis, but may be a configuration in which interference torque between the axes is corrected by feedforward or feedback.

  Next, an example of the internal configuration of the force sense consideration correction means 7 is shown in FIG. In the haptic consideration correction means 7, first, the forward conversion unit 18 performs forward conversion for calculating the hand position / posture from each motor position, calculates the hand position / posture, and the position command generated by the command generation means 1. A difference between the hand position / posture command and the hand position / posture calculated by the forward conversion unit 18 is calculated by the subtraction unit G3, and the calculated difference is converted into the tool coordinate system by the tool system coordinate conversion unit 10. The tool coordinate system is a coordinate system fixed to a tool or hand attached to the tip of the robot.

  The output of the tool system coordinate conversion unit 10 is input to the stiffness matrix unit 11, the product of the stiffness matrix and the vector that is the output of the tool system coordinate conversion unit 10 is obtained, and the product is used as the output of the stiffness matrix unit 11. Further, the differential value of each element of the output of the tool system coordinate conversion unit 10 is calculated by the differential unit 15, and the product of the vector composed of the calculated differential value and the damping matrix is output from the damping matrix unit 16, and the stiffness matrix unit 11 The outputs of the damping matrix unit 16 are added by the adding unit K2.

  Next, the force detection value detected by the force sensor of the robot 3 is converted into the tool coordinate system by the tool system coordinate conversion unit 17, and the converted force detection value is subtracted by the subtraction unit G4 from the output result of the addition unit K2. To do. Each element obtained as a result of the subtraction is multiplied by a variable proportional gain value switched by the parameter switching means 6 by the variable gain unit 12, and then the coordinate conversion to the orthogonal coordinate system is performed by the orthogonal system coordinate conversion unit 13. After the integration, the position command correction amount (position command correction amount) is input to the adding unit K1 of the robot control means 2. The variable gain unit 12 uses a force control parameter that is switched by the parameter switching means 6.

  In FIG. 4, the case where only the proportional gain with respect to the difference from the force detection value is changed as a parameter of the force control system has been described as an example. However, as shown in FIG. 11 and the damping matrix unit 16 may be given respective matrix element values using force control parameters switched by the parameter switching means 6, and each element of the stiffness matrix and damping matrix may be switched from the designated switching point.

  Further, as shown in FIG. 6, each matrix element value is given to the stiffness matrix unit 11 and the damping matrix unit 16 using the force control parameter switched by the parameter switching unit 6, and each element of the stiffness matrix and the damping matrix is designated. It is also possible to use a configuration in which a proportional integration unit 19 is provided instead of the variable gain unit 12 and the integration unit 14 and the gain multiplied by the difference from the force detection value is not switched.

  Further, instead of calculating the position command correction amount (position command correction amount) once converted into the tool coordinate system, as shown in FIG. 7, a tool system coordinate conversion unit 10 and an orthogonal system coordinate conversion unit 13 are provided. Instead, by providing the orthogonal system coordinate conversion unit 20 instead of the tool system coordinate conversion unit 17, the position command correction amount (position command correction amount) may be calculated and corrected in the orthogonal coordinate system.

  In this embodiment, the case where the force threshold value and the force control parameter are switched at one place during operation has been described as an example.

  FCNT 30, 2, 50, 3

And switching to condition number 2 at a point exceeding 30% of the moving distance and switching to condition number 3 at a point exceeding 50% of the moving distance may be used. . Further, instead of the parameter number, the value of the parameter to be switched may be directly described.

According to the first embodiment, the force threshold value and the force control parameter can be switched at the point designated by the command in the robot program for operating the robot at the switching point during operation. The force threshold value and the force control parameter can be switched, and both a safe stop at the time of misalignment and a high-speed insertion operation can be realized.
In addition, since the force control system parameters are changed during the operation, it is possible to operate the robot softly immediately after contact, and to operate the robot firmly at the final stage of pushing or insertion. While restraining, it becomes possible to perform an operation requiring a pushing force against the reaction force at a high speed.
Further, since the switching point can be designated immediately before the operation by a command of the program, it can be set finely for each operation.

Embodiment 2. FIG.
A force control apparatus according to Embodiment 2 of the present invention will be described below. The configuration of the apparatus is basically the same as that shown in FIG. 1, but the operation of the switching point designation means 5 is different. For example, the above-mentioned command parameters (switching point and condition number) sent from the switching point designating unit 5 to the parameter switching unit 6 are input from the input unit I indicated by a broken line in FIG. Specify to rewrite the value.

  For example, if the FCNT parameter (factor) value is set to FCNT (30, 1, 2), the parameter switching means 6 is set with condition number 1 from the start of the operation until it exceeds 30% of the movement amount of the operation. The force threshold value and the force control parameter that have been set are input to the force limit excess determining means 4 and the robot control means 2, and after exceeding 30% of the movement amount of the operation from the start of the operation, the force threshold value is set with condition number 2 And the force control parameter value input to the robot control means 2 is gradually switched to the value of condition number 2.

  According to the second embodiment, in addition to the above, the parameter of the command can be designated immediately before the operation by the input from the input means I, so that it can be set finely for each operation.

Embodiment 3 FIG.
FIG. 8 is a block diagram showing the configuration of the force control apparatus according to Embodiment 3 of the present invention. Unlike the first embodiment, the parameter switching means 6 switches only the force threshold value. Accordingly, the inside of the haptic consideration correction means 7 of the robot control means 2 shown in FIG. 2 of the first embodiment is also the proportional gain section 12a instead of the variable gain section 12 in the third embodiment as shown in FIG. Is a fixed parameter control system.

  According to the third embodiment, the force threshold value can be switched at the point designated by the command of the command robot program for operating the robot at the switching point during operation. Therefore, the force threshold value can be switched at the point designated during operation. Therefore, it is possible to achieve both a safe stop at the time of misalignment and a high-speed insertion operation.

Embodiment 4 FIG.
FIG. 10 is a block diagram showing the configuration of the force control device according to Embodiment 4 of the present invention. Unlike the first embodiment, the parameter switching means 6 switches only the force control parameter.

  According to the fourth embodiment, since the parameters of the force control system are changed in the middle of the operation, it is possible to operate the robot softly immediately after contact, and to operate the robot firmly at the final stage of pushing or insertion, and start of contact Immediately after that, it is possible to soften and suppress damage while performing work requiring a pushing force against the reaction force at high speed.

Embodiment 5 FIG.
FIG. 11 is a block diagram showing a configuration of a force control apparatus according to Embodiment 5 of the present invention. In the first embodiment, after the force limit value (force threshold value) is exceeded, the stop command is input to the command generating unit 1. However, in the fifth embodiment, the recovery operation determining unit 24 is provided in addition to the command generating unit 1. A stop command is also input to the operation determining means 24. In this embodiment, in FIG. 11, the force detection value of the robot 3 and the data of the motor position of each axis are not sent to the restoration operation determining means 24.

  When the stop command is input, the recovery operation determination unit 24 inputs a command generation command for performing a retreat operation to the operation start point of the work operation currently being performed to the command generation unit 1. When receiving the command generation command, the command generation unit 1 obtains the operation start point of the operation from the work operation program, and inputs the position command for the retreat operation to the robot control unit 2.

  According to the fifth embodiment, when the force limit value (force threshold value) is exceeded, the state of the robot is automatically returned to the previous operation start point, so that the state exceeding the force limit value continues. There is an effect that can be prevented.

Embodiment 6 FIG.
The configuration of the force control apparatus according to Embodiment 6 of the present invention is basically the same as that shown in FIG. The restoration operation determining means 24 inputs the motor position and force detection value of each axis from moment to moment from the robot 3, and stores the point at which the force detection value finally fell below a predetermined specified value during operation as the motor position of each axis. (For example, stored in the storage means M). When a stop command is input from the force limit excess determining means 4, each axis motor at a point below the specified value for performing a retreat operation to return to the last stored point below the specified value. A command generation instruction including a position is input to the command generation means 1. Upon receiving the command generation command, the command generation unit 1 inputs a position command for the retraction operation to the robot control unit 2 in accordance with the position of each axis motor at a point that is equal to or less than the received specified value.

  The prescribed value may be set in advance (for example, stored in the storage means M), or a ratio with the force threshold (for example, 0.8 times) may be set to always use the force limit excess determining means 4 A value obtained by multiplying a ratio (for example, stored in the storage means M or entered as a calculation formula in a program) set to a threshold value (force limit value) may be used as the specified value. In that case, the parameter switching means 6 always inputs the force threshold value to the restoration operation determining means 24 as indicated by a broken line in FIG. In this embodiment, the retraction operation is performed based on the motor position of each axis stored in the recovery operation determination unit 24 with the force threshold value. However, the motor detection value is not stored during the operation, but the motor position is stored. The position command output by the command generation means 1 when the value finally falls below the specified value may be stored, and an operation of returning to the stored position command point may be performed. In that case, the command generation means 1 always inputs the position command to the recovery operation determination means 24 as indicated by a broken line in FIG. The recovery operation determination unit 24 inputs a command generation command including a position command of a point that is equal to or less than the specified value to the command generation unit 1.

  According to the sixth embodiment, when the force limit value (force threshold) is exceeded, the state of the robot exceeds the force limit by automatically returning to a point where the force becomes equal to or less than the specified value. There is an effect that can be prevented from continuing. In addition, since the amount of movement when returning can be reduced compared to the retreat operation to the operation start point, there are effects of shortening the retreat operation time and preventing unexpected collisions.

Embodiment 7 FIG.
The configuration of the force control device according to Embodiment 7 of the present invention is basically the same as that shown in FIG. In the seventh embodiment, the recovery operation determination unit 24 selects the subsequent operation based on the force detection value when the stop command is input. When all the force detection values other than the pushing direction are equal to or less than the specified value, a command generation command for performing a retreat operation to return to the point where the force detection value in the pushing direction is finally equal to or less than the specified value is performed as in the sixth embodiment. Input to the command generation means 1.

  When at least one of the forces other than the pushing direction is equal to or greater than a specified value, a command generation command for performing a search operation at the stop point is input to the command generation unit 1 and the search operation is performed in a direction to return the operation of the robot 3 Let the action take place. If the force in the push-in direction falls below the specified value during the search operation, the command is stopped at that point, and then a command generation command (operation restart command) for generating a position command for restarting the original operation is input to the command generation means 1 To do.

  According to the seventh embodiment, when the force limit value (force threshold value) is exceeded, there is an effect that the operation can be automatically recovered by performing the search operation.

Embodiment 8 FIG.
The configuration of the force control apparatus according to Embodiment 8 of the present invention is basically the same as that shown in FIG. In the eighth embodiment, when the stop command is input from the force limit excess determination unit 4, the recovery operation determination unit 24 performs a search operation from the stop point when at least one of the forces other than the pushing direction is equal to or greater than a specified value. Rather than performing a point, a point corresponding to a predesignated ratio from the stop point to the point where the force in the push-in direction is the specified value or less at the end (if 0.5 is specified, for example) The command generation means 1 includes a command generation command including return point information for generating a position command for returning to the last point that is stored as a stop point and the force at which the force in the push-in direction is the specified value or less) To enter. When the robot 3 returns to the point, a command generation command for generating a position command for performing a search operation is transmitted to the command generation unit 1, and if the force in the pushing direction becomes a specified value or less in the search operation, the search is performed at that point. A command generation command (operation restart command) for generating a position command for stopping the operation and then restarting the original operation is input to the command generation means 1.

  According to the eighth embodiment, when the force limit value (force threshold value) is exceeded, a ratio specified in advance from the stop point to the point where the force in the pushing direction has finally become equal to or less than the specified value is satisfied. By returning to the point and performing a search operation from there, there is an effect that the operation can be recovered automatically and efficiently.

Embodiment 9 FIG.
The configuration of the force control apparatus according to Embodiment 9 of the present invention is basically the same as that shown in FIG. In Embodiment 9, when the stop command is input from the force limit excess determining unit 4 when the recovery operation determining unit 24 receives a stop command, the search operation is performed at the stop point when at least one of the forces other than the pushing direction is equal to or greater than a specified value. Rather than doing, remember the point where the force other than the pushing direction last became less than the specified value, and from the stop point to the last point where the force other than the pushing direction was less than the prescribed value Up to a point according to the ratio specified in advance (for example, if 0.5 is specified, the stop point is the last point stored and the middle point where the force other than the pushing direction is below the specified value) A command generation command including return point information for generating a position command for performing a return operation is input to the command generation means 1.

  When the robot 3 returns to the point, a command generation command for generating a position command for performing a search operation is transmitted to the command generation unit 1, and if the force in the pushing direction becomes a specified value or less in the search operation, the search is performed at that point. A command generation command (operation restart command) for generating a position command for stopping the operation and then restarting the original operation is input to the command generation means 1.

  According to the ninth embodiment, when a force limit value (force threshold value) is exceeded, according to a predesignated ratio from the stop point to the point where the force in the direction other than the push-in direction last falls below the specified value. By returning to the spot and performing the search operation from there, there is an effect that the operation can be recovered automatically and efficiently.

Embodiment 10 FIG.
FIG. 12 is a block diagram showing the configuration of the force control apparatus according to Embodiment 10 of the present invention. The operation in the parameter switching means 6a is different from that in the first embodiment. The parameter switching means 6a receives the motor position and force detection value of each axis from the robot 3, and sets a point where the force detection value in at least one direction exceeds a specified value (for example, stored in the storage means M) as a contact point. The force threshold is switched at the point where the amount of movement reaches the amount of movement designated by the switching point designation means 5, and switching of the force control parameter is started.

  According to the tenth embodiment, a point where a force detection value in at least one direction exceeds a specified value is defined as a contact point, and a movement amount from the contact point reaches a movement amount designated by the switching point designation unit. More accurate force control can be performed by switching the force threshold and starting the force control parameter switching.

Embodiment 11 FIG.
13 is a block diagram showing a configuration of a force control apparatus according to Embodiment 11 of the present invention. In the first embodiment, the force and moment are not detected by the force sensor, but the force and moment acting on the robot tip are estimated using the force estimation observer unit 25, and the estimated force estimated value is used. Different.

  Inside the force estimation observer unit 25, the motor position of each axis and the current of the motor that drives each axis are input. The motor speed and motor acceleration are calculated from the motor position of each axis, the drive torque required for the operation is calculated from the calculated motor position, speed and acceleration, and the difference from the drive torque calculated from the motor current is calculated for each axis. It is calculated as the disturbance torque. Further, using the Jacobian matrix calculated based on the motor position of each axis, the disturbance torque is converted into a force and a moment acting on the robot tip, and the converted force and the moment are used as a force estimation value to determine whether the force limit is exceeded. Input to the robot control means 2. The force limit excess determining means 4 and the robot control means 2 use the estimated force value instead of the detected force value.

  According to the eleventh embodiment, the force threshold value and the force control parameter can be switched at a point designated during operation without using a force sensor, and both a safe stop at the time of misalignment and a high-speed insertion operation can be achieved. Can be realized.

  As described above, according to the present invention, the force threshold value (force limit value) and the compliance control parameter can be switched during operation. In the section near the end of insertion where it is necessary to generate a pressing force against the reaction force, the parameter can be set to increase the force threshold and the compliance control can be set to make the operation harder. There is an effect that the operation can be speeded up while preventing an excessive force from being applied at the time of occurrence. Further, there is an effect that erroneous detection of an error can be prevented while preventing an excessive force from acting when a work error occurs.

  The present invention is not limited to the above-described embodiments, and it goes without saying that all possible combinations thereof are included.

  1 command generation means, 2 robot control means, 3 robot, 4 force limit excess discrimination means, 5 switching point designation means, 6, 6a parameter switching means, 7 force sense consideration correction means, 8 reverse conversion means, 9 axis position control Means, 9n Each axis position control unit, 10 Tool system coordinate conversion unit, 11 Stiffness matrix unit, 12 Variable gain unit, 12a Proportional gain unit, 13 Orthogonal system coordinate conversion unit, 14 Integration unit, 15 Differentiation unit, 16 Damping matrix unit , 17 Tool system coordinate conversion unit, 18 Forward conversion unit, 19 Proportional integration unit, 20 Orthogonal system coordinate conversion unit, 21 Proportional unit, 22 Proportional integration unit, 23 Differentiation unit, 24 Restoration operation determination means, 25 Force estimation observer unit, G1 to G4 subtraction unit, I input means, K1 to K2 addition unit, M storage means.

Claims (14)

  Based on a command for instructing a switching point for switching a parameter including at least one of a force limit value of a force acting on the robot tip according to a work operation to be performed by the robot from the switching point designating means and a force control parameter for compliance control, If the parameter switching means switches at least one of the force limit value and the force control parameter, and the force limit excess determining means determines that a force exceeding the force limit value is applied, the robot target is set according to the work action to be performed by the robot. A force control device, wherein a stop command for outputting a position command for decelerating and stopping the robot is input to a command generating means for outputting a position command indicating a position. The command generating means for outputting a position command indicating a target position of the robot every moment according to a work operation to be performed by a robot provided with a motor;
Generates a parameter condition including at least one of a force limit value of a force acting on the robot tip and a force control parameter for compliance control according to a work operation to be performed by the robot during the operation, and a command for instructing a switching point to be switched to the parameter condition. The switching point designating means;
The parameter switching means for starting switching of at least one of the force limit value and the force control parameter at a switching point designated based on a command from the switching point designation means;
Robot control means for controlling the robot in accordance with a position command from the command generation means, a force control parameter from the parameter switching means, a force detection value from the robot, and a signal indicating the motor position;
The force limit excess determining means for outputting a stop command when the force detection value from the robot exceeds the force limit value from the parameter switching means;
With
When the command generating means receives a stop command from the force limit excess determining means, it outputs a position command to decelerate and stop the robot.
The force control apparatus according to claim 1.   The force control apparatus according to claim 1 or 2, further comprising an input unit for rewriting at least one of the parameter condition and the switching point in the switching point designating unit.   When the stop command is received from the force limit excess determining means, a recovery operation for inputting to the command generating means a command generation command for outputting a position command for performing a retreat operation to the operation start point of the operation currently being executed. The force control apparatus according to claim 2, further comprising a determination unit.   The force detection value and the motor position from the robot are input, and the motor position when the force detection value finally falls below the specified value is stored, and stored when a stop command is received from the force limit excess determining means. And a recovery operation determining means for inputting a command generation command for outputting a position command for performing a retraction operation to return to a point where the force detection value finally becomes equal to or less than a specified value. The force control device according to claim 2 or 3. When the robot performs a push operation, and the robot has multiple motors and inputs multiple force detection values and motor positions from the robot, and at least the force detection value in the push direction finally falls below the specified value. Memorize the motor position of
When the force detection value in the push-in direction exceeds the force limit value and a stop command is received from the force limit excess determining means, from the respective points determined according to the relationship with the specified value of the force detection value in the direction other than the push-in direction The force control apparatus according to claim 2 or 3, further comprising a recovery operation determination unit that inputs a command generation command for outputting a position command for performing the search operation to the command generation unit. The recovery operation determining means is
When receiving a stop command from the force limit excess determining means,
If all the force detection values in directions other than the push-in direction are less than or equal to the specified value, a position command for performing a retreat operation to return to the point where the force-detected value in the push-in direction that was memorized is less than or equal to the specified value. Is input to the command generation means,
When at least one force detection value in a direction other than the pushing direction is equal to or greater than a specified value, a command generation command for outputting a position command for performing a search operation from the stop point is input to the command generation means. The force control device according to claim 6. The recovery operation determining means is
When receiving a stop command from the force limit excess determining means,
When at least one force detection value in a direction other than the pushing direction is greater than or equal to the specified value, up to a point of a predetermined ratio from the stop point to the point where the force detection value stored in the pushing direction is the specified value or less last 7. The force control device according to claim 6, wherein a command generation command for returning and then outputting a position command for performing a search operation is input to the command generation means. The recovery operation determining means is
Also stores the motor position when the force detection value in the direction other than the push-in direction finally falls below the specified value, and when a stop command is received from the force limit excess determining means,
When at least one force detection value in a direction other than the pushing direction is equal to or greater than a specified value, a predetermined ratio from the stop point to the last point where the force detection value in the direction other than the pushing direction is less than the specified value is stored. The force control device according to claim 6, wherein a command generation command for returning a position command for returning to the point and then outputting a position command for performing a search operation is input to the command generation means.   In the search operation, the recovery operation determination unit inputs a command generation command for outputting a position command for resuming the original operation at a point where the force detection value in the pushing direction is equal to or less than a specified value to the command generation unit. The force control device according to any one of claims 7 to 9, wherein   The restoration operation determining means inputs a position command from the command generating means, stores a position command when the force detection value finally becomes a specified value or less, and uses it instead of the motor position. The force control device according to any one of claims 5 to 10.   The force control device according to any one of claims 5 to 11, wherein the recovery operation determining means sets a prescribed value of the force detection value according to a force limit value of the parameter switching means.   The parameter switching means inputs a motor position and a force detection value from the robot, and a point where the force detection value in at least one direction exceeds a specified value is set as a contact point, and a movement amount from the contact point is determined by the switching point designation unit. The force control device according to claim 2, wherein the force limit value is switched at a point where the designated switching point is reached, and switching of the force control parameter is started.   The robot is equipped with a force estimation observer that inputs the motor position and motor current of the robot motor, estimates the force and moment acting on the robot tip, and obtains it as a force estimation value, and uses the estimated force estimation value instead of the force detection value The force control device according to claim 2, wherein:

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