Robot teaching device

Abstract

To provide a robot teaching device having an end effector operated by a teaching person intuitively, which can accurately measure interaction force between the end effector and a work object.SOLUTION: In a robot teaching device 5 equipped with a first end effector 1 gripped and operated by a teaching person, the first end effector 1 includes a first claw part 10 capable of switching its state between a state in which it can be opened and closed, and a state in which its opening or closing is fixed, a handle 12, and a first force sensor 11 for measuring force / torque between the first claw part 10 and the handle 12. Teaching data is generated on the basis of the output of the first force sensor 11 when the first claw part 10 is in the state in which the opening or closing is fixed and when the handle 12 is in the state in which it is gripped by the teaching person.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a robot teaching device for teaching a robot a predetermined task. [Background technology]

[0002] As a robot teaching system that teaches a robot a specific task, a system that allows a robot to reproduce a task demonstrated by a teacher using a teaching device is known. These systems acquire position and orientation information, as well as force and torque information, from the teaching device using sensors and use this information to calculate operation commands for the robot.

[0003] Patent Document 1 discloses a hand mechanism that can be held by an instructor and that can open and close multiple fingers to grasp an object to be manipulated. This hand mechanism has a tactile sensor and can measure the gripping force of the object to be manipulated.

[0004] In Patent Document 2, a robot is controlled using data obtained when a worker performs a predetermined task using a teaching device equipped with a force sensor. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2022-66085 [Patent Document 2] Japanese Patent Application Publication No. 9-47989 Summary of the Invention [Problem to be solved by the invention]

[0006] However, with the technology disclosed in Patent Document 1, although the instructor can teach the robot through intuitive operations, there is a problem in that it is not possible to teach tasks that require adjustment of the force between the robot and the work object, such as deburring, because the technology does not have a sensor for measuring the interaction force with the work object.

[0007] Furthermore, although the technology disclosed in Patent Document 2 can measure the interaction force with the work object, it has the problem of increasing engineering costs because it is necessary to develop a teaching device that simulates the work tools handled by the robot depending on the work content.

[0008] Although it is possible to configure a teaching device such as that disclosed in Patent Document 1 to be equipped with a force sensor that measures the interaction force with the work object, there is a problem in that the interaction force with the work object cannot be measured correctly depending on the point where the teacher holds the teaching device and the installation position of the force sensor.

[0009] In view of the above-mentioned problems, the present invention aims to provide a robot teaching device that has an operating device that can be intuitively operated by a teacher and that can accurately measure the interactive force between the operating device and a work object. [Means for solving the problem]

[0010] In order to solve the above problems, the robot teaching device of the present invention is a robot teaching device including a first end effector that is held and operated by a teacher, a second end effector that is connected to a robot, and a teaching data generation unit that generates teaching data for teaching the movement of the second end effector of the robot based on the operation of the first end effector, wherein the first end effector includes a first claw that can be switched between an open / close state where it can be opened and closed by operation of the teacher, and an open / closed fixed state where it cannot be opened or closed, a handle that can be held by the teacher, and a first force sensor that is installed between the first claw and the handle and can measure the force and torque acting between the first claw and the handle, and the teaching data generation unit generates the teaching data based on the output of the first force sensor when the first claw is in the open / closed fixed state and the handle is held by the teacher. [Effects of the Invention]

[0011] According to the present invention, the configuration of the first claw portion and handle in an openable / closable state makes it possible to realize a first end effector that can be intuitively operated by the instructor, and by using the output of the first force sensor when the first claw portion is in a fixed open / closed state and the instructor is holding only the handle, it is possible to provide a robot teaching device that can accurately measure the interaction force between the first end effector and the work object.

[0012] Problems, configurations, and effects other than those described above will become apparent from the following description of the embodiments. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 2 is a diagram showing a detailed configuration of a first end effector in the first embodiment. [Figure 2A] 10 is a diagram showing an image of an instructor operating a first end effector in which a first claw portion is in an openable / closable state in the first embodiment. FIG. [Figure 2B] FIG. 10 is a diagram showing an image of an instructor operating the first end effector in which the first claw portion is fixed in an open / closed state in the first embodiment. [Figure 3] 4A to 4C are diagrams illustrating the control of a robot equipped with a second end effector in the first embodiment. [Figure 4] 3A to 3C are diagrams illustrating coordinate system calibration using a calibration jig in the first embodiment and robot control using a transformation matrix obtained by the calibration. [Figure 5A] FIG. 3 is a diagram illustrating details of a first coordinate system calibration unit in the first embodiment. [Figure 5B] FIG. 3 is a diagram illustrating details of a second coordinate system calibration unit in the first embodiment. [Figure 6] FIG. 3 is a diagram showing a coordinate system related to the calculation of a force transformation matrix in the first embodiment. [Figure 7A] FIG. 2 is a diagram showing an image of a reference coordinate system in the first embodiment. [Figure 7B] FIG. 3 is a diagram illustrating a reference coordinate system setting unit in the first embodiment. [Figure 8]FIG. 2 is a diagram illustrating details of a robot control unit in the first embodiment. [Figure 9] FIG. 10 is a diagram showing a coordinate system related to the calculation of a force transformation matrix in the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, the present embodiment will be described with reference to the drawings. Note that the drawings show embodiments and implementation examples according to the principles of the present disclosure, but these are for understanding the present disclosure and are not to be used to interpret the present disclosure in a limiting manner. The descriptions in this specification are merely typical examples and are not intended to limit the scope or application of the present disclosure in any way.

[0015] Furthermore, although the following description is provided in sufficient detail to enable one skilled in the art to implement the present disclosure, other implementations and forms are possible, and changes to the configuration and structure and substitutions of various elements are possible without departing from the scope of the technical ideas of the present disclosure.

[0016] In the following description, when there are multiple identical or corresponding components, an alphabet may be added to the end of the reference numeral (number), but the alphabet may be omitted to refer to the multiple components collectively. For example, when there are two first claws 10a and 10b or two second claws 20a and 20b, these may be collectively referred to as the first claw 10 and the second claw 20.

[0017] [First Example] The configuration of a robot teaching device 5 according to a first embodiment of the present invention will be described. The robot teaching device 5 in this embodiment is mainly composed of a first end effector 1 that is held and operated by an instructor, a second end effector 2 that is connected to a robot 22, a teaching data generation unit 25 that generates teaching data 24 for controlling the robot 22, and a robot control unit 23 that controls the robot 22 using the teaching data 24.

[0018] 1 is a diagram showing the detailed configuration of a first end effector in Example 1. This first end effector 1 is composed of a pair of first claws 10a and 10b, a handle 12 that can be held by an instructor, and a first force sensor 11 that is installed between the first claws 10 and the handle 12 and can measure force / torque information (information on at least one of force and torque: the same applies hereinafter) acting between the first claws 10 and the handle 12.

[0019] In this embodiment, the first claw portions 10a and 10b move parallel to the first claw portion opening / closing direction 101 by a guide such as the opening / closing mechanism 13, and the first claw portions 10a and 10b move (open and close) symmetrically by a parallel mechanism not shown.

[0020] The first claws 10a and 10b are connected to the opening / closing mechanism 13 via opening / closing operation units 14a and 14b, and an instructor can manually open or close the first claws 10 by pressing the opening / closing operation unit 14 to open or close the opening / closing mechanism 13. In addition, the first claws 10a and 10b each have a first claw gripping structure 100 (hereinafter, sometimes simply referred to as the gripping structure 100).

[0021] The opening / closing operation unit 14 may be mounted on the handle 12. For example, the opening / closing operation unit 14 may be in the shape of a lever, and the opening / closing operation unit 14 and the first claw unit 10 may be connected by a wire (not shown), so that when the opening / closing operation unit 14 is operated, the power thereof opens or closes the first claw unit 10 via the wire.

[0022] In addition, the first end effector 1 may have a built-in electric actuator (not shown), the electric actuator is connected to the first claw portion 10, and when the opening / closing operation portion 14 is operated, the electric actuator is driven to open and close the first claw portion 10.

[0023] When the opening / closing fixing mechanism 15 is operated, the open / close state of the opening / closing mechanism 13 is fixed, and the first claw portion 10 is fixed in that position. Therefore, even when the opening / closing operation unit 14 is operated, the first claw portion 10 does not move (does not open or close). In the example of FIG. 1 , the opening / closing fixing mechanism 15 is screw-shaped and is connected to the opening / closing operation units 14a and 14b by links (not shown). When the screw is tightened, the first claw portion 10 is placed in a fixed open / close state that prevents it from being opened or closed. When the screw is loosened, the opening / closing fixing mechanism 15 becomes slidable in a direction perpendicular to the first claw opening / closing direction 101, and the first claw portion 10 is placed in an openable state that allows it to be opened or closed by the instructor's operation. In this way, in this embodiment, by operating the opening / closing fixing mechanism 15, the first claw portion 10 can be switched between an openable state that allows it to be opened or closed by the instructor's operation and an openable state that prevents it from being opened or closed.

[0024] The position and orientation (at least one of position and orientation: the same applies hereinafter) of the first measured unit 16 is measured by a position and orientation measurement unit 31, which will be described later. The position and orientation measurement unit 31 is, for example, an infrared camera, and recognizes a plurality of optical markers 160 provided on the first measured unit 16, and recognizes the target object based on the arrangement pattern of the plurality of optical markers 160.

[0025] The information processing unit 17 manages output information from the sensors mounted on the first end effector 1 and transmits the information to an external processing device (external device). In the example of FIG. 1, the information processing unit 17 receives force / torque information output from the first force sensor 11 and transmits the information to the external processing device using a wireless communication system. By using a wireless communication system, the signal wiring connected to the first end effector 1 can be reduced, and it is expected that the robot teaching device will be easy for the instructor to use.

[0026] The battery 19 is built into, for example, the handle 12 or the information processing unit 17, and supplies power to the first force sensor 11 and the information processing unit 17. By incorporating the battery 19, it is possible to reduce the amount of power wiring connected to the first end effector 1, and it is expected that the robot teaching device will be easy for the instructor to use.

[0027] 2A is a diagram showing an image of an instructor 32 operating the first end effector 1 in which the first claw portion 10 in the first embodiment is in an openable / closable state. In the example shown in FIG. 2A, the instructor 32 opens and closes the first claw portion 10 by operating the opening / closing operation portion 14b with his thumb and the opening / closing operation portion 14a with his index finger.

[0028] 2B is a diagram showing an image of an instructor 32 operating the first end effector 1 in which the first jaw 10 is in an open / closed fixed state in the first embodiment. In the example shown in FIG. 2B, the position of the first jaw 10 is fixed by tightening the open / close fixing mechanism 15 with a screw. The instructor 32 holds only the handle 12 and performs a desired task.

[0029] 2A, when the instructor 32 performs a desired task while touching the opening / closing operation unit 14, for example, the interaction force with the external environment acting on the first claw 10 is partially supported by the hand of the instructor 32, making it difficult to accurately measure the interaction force with the first force sensor 11. For this reason, it is desirable to obtain the output (measured values ​​of force and torque) of the first force sensor 11 with the first claw 10 fixed in the opening / closing state and the instructor 32 holding only the handle 12, as shown in FIG.

[0030] 3 is a diagram illustrating the control of the robot 22 equipped with the second end effector 2 in the first embodiment. The robot 22 is equipped with a plurality of actuators (not shown), and by controlling the positions or forces of these actuators, it is possible to control the position or force of the second end effector 2 equipped at the tip of the robot 22.

[0031] The second end effector 2 is connected to the robot 22 via a second force sensor 21, and the second force sensor 21 is installed between the second end effector 2 and the robot 22 and is capable of measuring the force and torque between the second end effector 2 and the robot 22. A pair of second claws 20a and 20b are connected to the tip of the second end effector 2, and the second claws 20a and 20b can be opened and closed in a second claw opening / closing direction 201 by power from the robot 22. The second claws 20a and 20b each include a second claw gripping structure 200 (hereinafter, may be simply referred to as gripping structure 200) that has at least a partial structure identical to the gripping structure 100 of the first claw 10.

[0032] The flow of control of the robot 22 will be described. First, teaching data 24 is generated based on the position and orientation information of the first end effector 1 from the position and orientation measurement unit 31 and the force and torque information from the first force sensor 11, which are obtained when a desired task is performed using the first end effector 1. The teaching data 24 is data for controlling the robot 22. In this embodiment, the teaching data 24 is data for teaching the movement of the second end effector 2 of the robot 22. This teaching data 24 is input to the robot control unit 23, and based on the information included in the teaching data 24, a robot control command 230 is sent from the robot control unit 23 to the robot 22 to drive the robot 22. The robot control command 230 is, for example, the hand position and hand velocity of the robot 22, the joint positions, joint velocities, and joint torques of the robot 22, etc.

[0033] A specific flow from teaching to operation by the robot 22 will be described.

[0034] As an example, consider the task of removing burrs from a machined part. First, in the teaching procedure, the instructor holds the first end effector 1 as shown in FIG. 2A and opens and closes the first jaw 10. The instructor then grips a tool for deburring using the first jaw gripping structure 100 and fixes the position of the first jaw 10 using the opening / closing fixing mechanism 15 to fix the gripping state of the tool. At this time, it is desirable to constrain the position and posture relationship between the first end effector 1 and the tool. The instructor then holds the handle 12 and brings the tool fixed to the first end effector 1 into contact with the machined part to perform the deburring task. Here, because the instructor holds only the handle 12, the first force sensor 11 can accurately measure the reaction force the tool receives from the machined part, i.e., the force information required to perform the deburring task. The instructor acquires the position and orientation information of the first end effector 1 from the position and orientation measurement unit 31 and the force and torque information of the first force sensor 11 at regular time intervals (for example, once every 0.1 seconds) while the deburring operation is being performed, and arranges them in chronological order to create teaching data 24. If the robot 22 is controlled using this teaching data 24 so that the positions and orientations of the first end effector 1 and the second end effector 2 and the forces and torques of the first force sensor 11 and the second force sensor 21 match, respectively, the robot 22 will be able to perform the desired deburring operation.

[0035] In the above example, if the configurations of the first end effector 1 and the second end effector 2 (e.g., dimensions, positioning of force sensors, etc.) are completely identical, the teaching data 24 can be used for robot control without any particular modification. However, if there is a machine difference between the first end effector 1 and the second end effector 2 (e.g., assembly accuracy, component processing accuracy, etc.), the data as is may not be able to reproduce the desired deburring operation. For this reason, in order to compensate for the machine difference between the first end effector 1 and the second end effector 2, it is necessary to calibrate each measurement coordinate system.

[0036] FIG. 4 is a diagram illustrating coordinate system calibration using the calibration jig 30 in the first embodiment, and control of the robot 22 using the transformation matrices 180 and 280 obtained by the calibration.

[0037] The first end effector 1 and the second end effector 2 are designed to be easy for the instructor 32 to grasp, and therefore the configurations of the measurement reference positions of each end effector, the attachment positions of the force sensors, etc. may differ. For this reason, if the respective coordinate systems are not calibrated correctly, correct control will not be possible.

[0038] In view of the above problem, in this embodiment, a calibration jig 30 is used to calibrate each coordinate system.

[0039] The calibration jig 30 has a graspable structure 36 that, when grasped by the grasping structures 100 and 200 of the first and second claw portions of the first and second end effectors, uniquely determines the position and orientation of the calibration jig 30 relative to each end effector.

[0040] For example, the gripping structure 36 has a concave shape that fits precisely into the convex shape of the gripping structures 100 and 200, and the position and orientation of the calibration jig 30 with respect to each end effector are uniquely determined by this fit and gripping force.

[0041] The position and orientation of the third measured portion 37 is measured by a position and orientation measurement unit 31, which will be described later. The position and orientation measurement unit 31 (for example, an infrared camera) recognizes a plurality of optical markers 370 provided on the third measured portion 37, and recognizes the object based on the arrangement pattern of the plurality of optical markers 370.

[0042] First, the calibration of the first end effector 1 will be described.

[0043] The first end effector 1, with the calibration jig 30 gripped by the first claw 10, is measured using a position and orientation measurement unit 31 (e.g., an infrared camera), and position and orientation information 310 (hereinafter, the position and orientation measurement data 310 indicates data output from the position and orientation measurement unit 31 and does not necessarily include information on the first end effector 1 and the calibration jig 30) measured by the position and orientation measurement unit 31, and force and torque information 110 (hereinafter, first force sensor data 110) output from the first force sensor 11 (as a result of simultaneous measurement) are input to the first coordinate system calibration unit 18.

[0044] The position and orientation information of the first end effector 1 measured by the position and orientation measurement unit 31 is the position and orientation of the first end effector coordinate system ΣE1 defined based on the first measured part 16. Furthermore, the position and orientation information of the calibration jig 30 held (fixed) by the first jaw 10 measured by the position and orientation measurement unit 31 is the position and orientation of the calibration jig coordinate system ΣC defined based on the third measured part 37.

[0045] The first coordinate system calibration unit 18 calculates a first transformation matrix 180 for converting the position and orientation of the first end effector coordinate system ΣE1 and the force and torque information based on the measurement origin of the first force sensor 11 into position and orientation and force and torque information based on an arbitrary coordinate system defined in association with the calibration jig coordinate system ΣC. In other words, the first coordinate system calibration unit 18 calculates the first transformation matrix 180 for converting the position and orientation of the first end effector coordinate system ΣE1 (the position and orientation information of the first end effector 1) and the force and torque information based on the measurement origin of the first force sensor 11 into data expressed in a reference coordinate system defined in association with the first claw gripping structure 100.

[0046] Next, the calibration of the second end effector 2 will be described.

[0047] The second end effector 2, with the calibration jig 30 gripped by the second claw 20, is measured using a position and orientation measurement unit 31 (e.g., an infrared camera), and the robot state quantity 220 obtained from the robot 22 (hereinafter, robot position and orientation measurement data 220), the position and orientation information of the calibration jig 30 gripped (fixed) by the second claw 20 measured by the position and orientation measurement unit 31, and force and torque information 210 output from the second force sensor 21 (hereinafter, second force sensor data 210) (as simultaneous measurement results) are input to a second coordinate system calibration unit 28.

[0048] The robot position and orientation measurement data 220 is, for example, the joint angles of the robot 22, and the hand position of the robot 22, that is, the reference position and orientation of the second end effector 2, can be calculated by solving a forward kinematics calculation.

[0049] The second coordinate system calibration unit 28 calculates a second transformation matrix 280 for converting the reference position and orientation of the second end effector 2 and the force and torque information based on the measurement origin of the second force sensor 21 into position and orientation and force and torque information based on an arbitrary coordinate system defined in association with the calibration jig coordinate system ΣC. That is, the second coordinate system calibration unit 28 calculates the second transformation matrix 280 for converting the reference position and orientation of the second end effector 2 (the position and orientation information of the second end effector 2) and the force and torque information based on the measurement origin of the second force sensor 21 into data expressed in a reference coordinate system defined in association with the second claw gripping structure 200.

[0050] Here, the first transformation matrix 180 and the second transformation matrix 280 are calculated based on a common coordinate system defined in relation to the calibration jig coordinate system ΣC.

[0051] Next, a procedure for creating the teaching data 24 using the first end effector 1 will be described.

[0052] The state in which an instructor 32 grasps the first end effector 1 and performs a desired task is measured by the position and orientation measurement unit 31. Position and orientation measurement data 310 and first force sensor data 110 are acquired at a fixed sampling period and input to the teaching data generation unit 25 as time-series data.

[0053] Based on the first transformation matrix 180, the teaching data generation unit 25 transforms the position and orientation measurement data 310 and the first force sensor data 110 into position, orientation, and force, and torque information based on an arbitrary coordinate system defined in association with the calibration jig coordinate system ΣC, and stores them as teaching data 24. That is, the teaching data generation unit 25 uses the first transformation matrix 180 to transform the position and orientation measurement data 310 (position and orientation information of the first end effector 1) and the first force sensor data 110 (force and torque information of the first force sensor 11) into teaching data 24 of position, orientation, and force, and torque expressed in a reference coordinate system defined in association with the gripping structures 100 and 200.

[0054] Finally, we will explain the control procedure for the robot 22 based on the teaching data 24. The robot 22 is controlled so as to reproduce the position, posture, and force, torque information stored in the teaching data 24.

[0055] The robot control unit 23 calculates and transmits to the robot 22 a robot control command 230 so as to match the position / posture and force / torque information stored in the teaching data 24 with data obtained by converting feedback data 26 based on robot position / posture measurement data 220 obtainable from the robot 22 and second force sensor data 210 that is the output of the second force sensor 21, using a second transformation matrix 280, into position / posture and force / torque information based on an arbitrary coordinate system defined in association with the calibration jig coordinate system ΣC. That is, the robot control unit 23 converts the robot position and orientation measurement data 220 (position and orientation information of the second end effector 2) and the second force sensor data 210 (force and torque information of the second force sensor 21) into position, orientation, and force and torque data expressed in a reference coordinate system defined in association with the gripping structures 100 and 200 using the second transformation matrix 280, and calculates and transmits to the robot 22 a robot control command 230 so as to make these data follow the position, orientation, and force and torque information stored in the teaching data 24. By controlling the robot 22 in accordance with the time series shown in the teaching data 24, the robot 22 behaves so as to reproduce the positions and forces of the work performed by the instructor 32.

[0056] Since the first transformation matrix 180 and the second transformation matrix 280 are values ​​based on a common coordinate system defined in association with the calibration jig coordinate system ΣC, by applying the transformation matrices to the teaching data 24 and feedback data 26 that have different reference coordinate systems, it becomes possible to control them based on a common coordinate system, and as a result, the desired work position and force can be accurately reproduced.

[0057] FIG. 5A is a diagram illustrating details of the first coordinate system calibration unit 18 in the first embodiment.

[0058] The first coordinate system calibration unit 18 calculates a first transformation matrix 180 based on the first force sensor data 110, the position and orientation measurement data 310, and the calibration jig force-torque data 300 obtained by measuring or calculating the force and torque applied to the calibration jig 30.

[0059] Furthermore, first transformation matrix 180 includes a first position transformation matrix 1801 for transforming position / posture information, and a first force transformation matrix 1802 for transforming force / torque information.

[0060] FIG. 5B is a diagram illustrating details of the second coordinate system calibration unit in the first embodiment.

[0061] The second coordinate system calibration unit 28 calculates a second transformation matrix 280 based on the second force sensor data 210, the position and orientation measurement data 310, the robot position and orientation measurement data 220, and the calibration jig force and torque data 300 obtained by measuring or calculating the forces and torques applied to the calibration jig 30.

[0062] Furthermore, second transformation matrix 280 includes second position transformation matrix 2801 for transforming position / posture information, and second force transformation matrix 2802 for transforming force / torque information.

[0063] FIG. 6 is a diagram showing a coordinate system related to the calculation of the first transformation matrix 180 in the first end effector 1 in the first embodiment.

[0064] In this embodiment, it is assumed that the position and orientation of the calibration jig center of gravity 33 as viewed from the calibration jig coordinate system ΣC of the calibration jig 30 and the calibration jig gravity 34 based on the weight data of the calibration jig 30 are known, and the calibration jig force torque data 300 uses this calibration jig gravity 34.

[0065] The position and orientation measurement unit 31 measures the first end effector 1 in a state where the calibration jig 30 is gripped by the first jaw 10. The position and orientation measurement data 310 measured by the position and orientation measurement unit 31 acquires the position and orientation information of each measured part with the world coordinate system ΣW as the reference. In the example of Fig. 6, the position and orientation of the calibration jig coordinate system ΣC and the first end effector coordinate system ΣE1 can be acquired, but the first force sensor coordinate system ΣF1, which is the measurement origin of the first force sensor 11, cannot be measured.

[0066] The first position transformation matrix 1801 can be directly obtained by calculating the relative positional relationship between the calibration jig coordinate system ΣC and the first end effector coordinate system ΣE1.

[0067] On the other hand, the first force transformation matrix 1802 cannot be directly acquired because the first force sensor coordinate system ΣF1 cannot be measured. Therefore, the first force transformation matrix 1802 is acquired by calculating the relative positional relationship between the calibration jig coordinate system ΣC and the first force sensor coordinate system ΣF1 using the calibration jig force torque data 300.

[0068] When the direction of gravitational acceleration with respect to the world coordinate system ΣW is known (for example, the -Z-axis direction of the world coordinate system ΣW), force and torque information of the calibration jig gravity 34 seen from the calibration jig coordinate system ΣC can be calculated from the position and orientation of the calibration jig coordinate system ΣC measured by the position and orientation measurement unit 31 and the known position and orientation of the calibration jig center of gravity 33. Furthermore, force and torque information of the calibration jig gravity 34 seen from the first force sensor coordinate system ΣF1 can be acquired from the output of the first force sensor 11. From the above two pieces of force and torque information, the relative positional relationship between the calibration jig coordinate system ΣC and the first force sensor coordinate system ΣF1 can be calculated.

[0069] To improve the accuracy of the calculation, various information in multiple directions other than that of the first end effector 1 shown in Fig. 6 may be used to calculate the relative positional relationship. In this case, it is desirable to have a stand (not shown) that can fix the handle 12 to the ground at any position.

[0070] The second position transformation matrix 2801 and the second force transformation matrix 2802 are also calculated using the above procedure for the second end effector 2. The reference position and orientation of the second end effector 2 may be calculated by solving a forward kinematic calculation using the joint angles of the robot 22 included in the robot position and orientation measurement data 220, or, similar to the first measured unit 16, a second measured unit (not shown) may be mounted on the second end effector 2 and values ​​of the position and orientation of the second measured unit measured by the position and orientation measurement unit 31 may be used.

[0071] FIG. 7A is a diagram showing an image of the reference coordinate system ΣT in the first embodiment.

[0072] The reference coordinate system ΣT is defined in association with the calibration jig coordinate system ΣC, and is set by the instructor 32 as a relative position and orientation seen from the calibration jig coordinate system ΣC. For example, the gripping center position of the claws, the tip position of the object to be gripped by the claws, etc. are assumed.

[0073] FIG. 7B is a diagram illustrating the reference coordinate system setting unit 40 in the first embodiment.

[0074] When the reference coordinate system ΣT is set by the instructor 32, information about the reference coordinate system ΣT is transmitted from the reference coordinate system setting unit 40 to the first and second coordinate system calibration units 18 and 28. Based on the information about the reference coordinate system ΣT set by the reference coordinate system setting unit 40, the first and second coordinate system calibration units 18 and 28 calculate first and second transformation matrices 180 and 280 that transform position / posture information and force / torque information based on the reference coordinate system ΣT.

[0075] 8 is a diagram showing details of the robot control unit 23 in the first embodiment. The robot control unit 23 in this embodiment is composed of a position coordinate conversion unit 231, a force coordinate conversion unit 232, an impedance control force calculation unit 233, and a command value calculation unit 234. The position and orientation information of the feedback data 26 is converted into the reference coordinate system ΣT by the position coordinate conversion unit 231 based on a second transformation matrix 280, and the force and torque information of the feedback data 26 is converted into the reference coordinate system ΣT by the force coordinate conversion unit 232 based on the second transformation matrix 280.

[0076] The robot control unit 23 in FIG. 8 performs impedance control such that a target impedance characteristic is set for the difference between the position and posture information of the teaching data 24 and the position and posture information of the feedback data 26 converted based on the reference coordinate system ΣT (i.e., the position and posture information of the second end effector 2 expressed in the reference coordinate system ΣT).

[0077] The instructor 32 sets the target impedance characteristics in advance using the impedance characteristics setting unit 41. The target impedance characteristics are, for example, spring characteristics, damper characteristics, and mass characteristics.

[0078] The impedance control force calculation unit 233 calculates the impedance control force / torque 2330 based on the difference between the position / posture information in the teaching data 24 and the output of the position coordinate conversion unit 231, and the target impedance characteristics set by the impedance characteristics setting unit 41.

[0079] The command value calculation unit 234 calculates a robot control command 230 based on the impedance control force / torque 2330 output from the impedance control force calculation unit 233, the force / torque information in the teaching data 24, and the output of the force coordinate conversion unit 232, and transmits the robot control command 230 to the robot 22.

[0080] The robot 22 is controlled by the robot control unit 23 described above so that the target impedance characteristic set by the instructor 32 is realized with respect to the reference coordinate system ΣT set by the instructor 32.

[0081] According to this embodiment, first, using the first end effector 1 having the openable / closable first jaw 10 as shown in FIG. 1, a desired task can be performed while imagining the operation of the second end effector 2 mounted on the robot 22, enabling intuitive robot teaching. Furthermore, by acquiring the output (measured values ​​of force and torque) of the first force sensor 11 with the first jaw 10 in the open / closed fixed state and the instructor 32 grasping only the handle 12 as shown in FIG. 2B, the interactive force acting on the first jaw 10 with the external environment can be accurately measured. Next, by using a calibration jig 30 as shown in FIG. 3, even if there is a difference in configuration between the first end effector 1 and the second end effector 2, the position and force measured by the first end effector 1 can be accurately reproduced by the robot 22 by calibrating the positional relationship between the respective coordinate systems.

[0082] [Second Example] The configuration of a robot teaching device 5 according to a second embodiment of the present invention will be described. In this embodiment, differences from the first embodiment will be mainly described, and configurations for which description is omitted are the same as those in the first embodiment.

[0083] FIG. 9 is a diagram showing a coordinate system related to the calculation of the first transformation matrix 180 in the first end effector 1 in the second embodiment.

[0084] In this embodiment, the calibration jig 30 is equipped with a third force sensor 35, and the positional relationship between the third force sensor coordinate system ΣF3, which is the measurement origin of the third force sensor 35, and the calibration jig coordinate system ΣC is known.

[0085] The position and orientation of the first end effector 1 in a state where the calibration jig 30 is gripped by the first jaw 10 is measured by the position and orientation measurement unit 31. In the example of Fig. 9, the positions and orientations of the calibration jig coordinate system ΣC and the first end effector coordinate system ΣE1 can be acquired, but the first force sensor coordinate system ΣF1 and the third force sensor coordinate system ΣF3 cannot be measured.

[0086] The first force transformation matrix 1802 cannot be directly acquired because the first force sensor coordinate system ΣF1 cannot be measured. Therefore, the first force transformation matrix 1802 is acquired by calculating the relative positional relationship between the calibration jig coordinate system ΣC and the first force sensor coordinate system ΣF1 using the output of the third force sensor 35 as the calibration jig force torque data 300.

[0087] The instructor 32 fixes the first jaw 10 of the first end effector 1 in the open / closed state, grips the handle 12, and presses the third force sensor 35 provided on the calibration jig 30 against a structure in the surrounding environment. As a result, the third force sensor 35 outputs force / torque information between the structure in the surrounding environment and the calibration jig 30 (i.e., force / torque information acting on the calibration jig 30).

[0088] Since the positional relationship of the third force sensor coordinate system ΣF3 as viewed from the calibration jig coordinate system ΣC is known, it is possible to calculate force and torque information acting on the third force sensor 35 as viewed from the calibration jig coordinate system ΣC from the output of the third force sensor 35. Furthermore, it is possible to obtain force and torque information acting on the third force sensor 35 as viewed from the first force sensor coordinate system ΣF1 from the output of the first force sensor 11. From the above two pieces of force and torque information, it is possible to calculate the relative positional relationship between the calibration jig coordinate system ΣC and the first force sensor coordinate system ΣF1.

[0089] To improve the accuracy of the calculation, various information in a plurality of directions other than that of the first end effector 1 shown in FIG. 9 may be used to calculate the relative positional relationship.

[0090] In the second end effector 2, the second force transformation matrix 2802 is also calculated using the above procedure.

[0091] According to this embodiment, it is sufficient that the third force sensor 35 is mounted with high precision in terms of its positional relationship with the calibration jig coordinate system ΣC, and since the nominal error factors with respect to the design value can be reduced compared to the first embodiment, it is expected that the second force transformation matrix 2802 can be calculated with high precision.

[0092] [summary] As described above, the robot teaching device 5 in this embodiment includes the first end effector 1 that is held and operated by a teacher, the second end effector 2 that is connected to the robot 22, and the teaching data generating unit 25 that generates teaching data 24 for controlling the robot 22 (for teaching the operation of the second end effector 2 of the robot 22 (when the robot 22 performs a predetermined task) based on the operation of the first end effector 1). In this robot teaching device 5, the first end effector 1 can be opened and closed by the operation of the teacher. The teaching data generating unit 25 generates the teaching data 24 based on the output (measured values ​​of force and torque) of the first force sensor 11 when the first claw 10 is in the open / closed fixed state and the handle 12 is held by the instructor.

[0093] Furthermore, the robot teaching device 5 in this embodiment includes: a second force sensor 21 that is installed between the robot 22 and the second end effector 2 and is capable of measuring the force and torque acting between the robot 22 and the second end effector 2; a position and orientation measurement unit 31 (e.g., an infrared camera) that measures the position and orientation of the first end effector 1; the teaching data 24 that is generated by the teaching data generation unit 25 based on the output of the position and orientation measurement unit 31 and the output of the first force sensor 11; and a robot control unit 23 that controls the robot 22 (the operation of the second end effector 2 of the robot 22) based on the position and orientation of the second end effector 2 and the output of the second force sensor 21. The second end effector 2 has a second claw 20 that is opened and closed by power from the robot 22 and has a gripping structure 200 that has at least a partial structure identical to the gripping structure 100 of the first claw 10.

[0094] The robot teaching device 5 in this embodiment is capable of measuring the position and orientation by the position and orientation measurement unit 31, and includes a calibration jig 30 that is fixed so that the position and orientation of the first claw unit 10 and the second claw unit 20 is uniquely determined with respect to the gripping structures 100 and 200; a first coordinate system calibration unit 18 that calculates a first transformation matrix 180 for converting the position and orientation of the calibration jig 30 fixed to the first claw unit 10, the position and orientation of the first end effector 1, and the force and torque output from the first force sensor 11 into data expressed in a reference coordinate system defined in association with the gripping structure 100, based on results of simultaneously measuring the position and orientation of the calibration jig 30 fixed to the second claw unit 20, the position and orientation of the second end effector 2, and the force and torque output from the second force sensor 21; and a second coordinate system calibration unit 28 that determines a second transformation matrix 280 that transforms the position and orientation of the second end effector 2 and the force and torque measurement values ​​of the second force sensor 21 into data expressed in the reference coordinate system defined in association with the grasping structure 200, based on the results of simultaneously measuring the position and orientation of the second end effector 2 and the force and torque measurement values ​​of the second force sensor 21, into teaching data 24 of the position, orientation, and force and torque expressed in the reference coordinate system, using the first transformation matrix 180, and the robot control unit 23 that transforms the position and orientation of the second end effector 2 and the force and torque measurement values ​​of the second force sensor 21 into position, orientation, and force and torque data expressed in the reference coordinate system, using the second transformation matrix 280, and causes these data to follow the position, orientation, and / or force and torque of the teaching data 24.

[0095] Furthermore, in the robot teaching device 5 in this embodiment, the first transformation matrix 180 and the second transformation matrix 280 have a position transformation matrix that transforms position and posture, and a force transformation matrix that transforms force and torque, respectively, and the first coordinate system calibration unit 18 and the second coordinate system calibration unit 28 each calculate the force transformation matrix based on data of force and torque applied to the calibration jig 30 (calibration jig force torque data 300).

[0096] Furthermore, the robot teaching device 5 in this embodiment calculates the force and torque (calibration jig force-torque data 300) acting on the calibration jig 30 based on the weight of the calibration jig 30 and the position of the center of gravity of the calibration jig 30 as viewed from the reference coordinate system (first embodiment).

[0097] Furthermore, in the robot teaching device 5 in this embodiment, the calibration jig 30 includes a third force sensor 35 that measures the force and torque (calibration jig force-torque data 300) applied to the calibration jig 30 (second embodiment).

[0098] Moreover, the robot teaching device 5 in this embodiment includes a reference coordinate system setting unit 40 that sets the reference coordinate system, and an impedance characteristic setting unit 41 that sets target impedance characteristics with respect to the difference between the position and posture of the teaching data 24 and the position and posture of the second end effector 2 expressed in the reference coordinate system.

[0099] According to this embodiment, the configuration of the first claw portion 10 and the handle 12 in an openable / closable state makes it possible to realize a first end effector 1 that can be intuitively operated by an instructor, and by using the output of the first force sensor 11 when the first claw portion 10 is in an open / closed fixed state and the instructor is holding only the handle 12, it is possible to provide a robot teaching device 5 that can accurately measure the interaction force between the first end effector 1 and the work object.

[0100] The present invention is not limited to the above-described embodiments and includes various modifications. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and the present invention is not necessarily limited to those including all of the described configurations. Furthermore, it is possible to replace part of the configuration of one embodiment with the configuration of another embodiment, or to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace part of the configuration of each embodiment with other configurations.

[0101] Furthermore, the above-described configurations, functions, processing units, processing means, etc. may be partially or entirely implemented in hardware, for example, by designing them as integrated circuits. The above-described configurations, functions, etc. may also be implemented in software, with a processor interpreting and executing a program that implements each function. Information such as the programs, tables, and files that implement each function can be stored in a memory, a storage device such as a hard disk or SSD (Solid State Drive), or a recording medium such as an IC card, SD card, or DVD.

[0102] In addition, the control lines and information lines shown are those that are considered necessary for the explanation, and do not necessarily show all the control lines and information lines in the product. In reality, it can be assumed that almost all components are interconnected. [Explanation of symbols]

[0103] 1...first end effector, 10...first claw portion, 100...first claw portion gripping structure, 101...first claw portion opening / closing direction, 11...first force sensor, 12...handle, 13...opening / closing mechanism, 14...opening / closing operation unit, 15...opening / closing fixing mechanism, 16...first measured unit, 160...optical marker, 17...information processing unit, 18...first coordinate system calibration unit, 180...first transformation matrix, 19...battery, 2...Second end effector, 20...Second claw portion, 200...Second claw portion gripping structure, 201...Second claw portion opening / closing direction, 21...Second force sensor, 22...Robot, 23...Robot control unit, 24...Teaching data, 25...Teaching data generation unit, 26...Feedback data, 28...Second coordinate system calibration unit, 280...Second transformation matrix, 30... calibration jig, 31... position and orientation measurement unit, 32... teacher, 33... calibration jig center of gravity, 34... calibration jig gravity, 35... third force sensor, 36... grasped structure, 37... third measured unit, 370... optical marker, 40...reference coordinate system setting unit, 41...impedance characteristic setting unit, 5...Robot teaching device, ΣC...calibration jig coordinate system, ΣE1...first end effector coordinate system, ΣF1...first force sensor coordinate system, ΣF3...third force sensor coordinate system, ΣT...reference coordinate system

Claims

1. A robot teaching device including a first end effector that is held and operated by a teacher, a second end effector that is connected to a robot, and a teaching data generation unit that generates teaching data for teaching the robot to operate the second end effector based on the operation of the first end effector, The first end effector a first claw portion that can be switched between an openable / closeable state where the claw can be opened and closed and a fixed open / close state where the claw cannot be opened or closed by an operation by the instructor; a handle that can be held by the instructor; a first force sensor that is installed between the first claw portion and the handle and that is capable of measuring at least one of a force or a torque acting between the first claw portion and the handle; The teaching data generation unit A robot teaching device that generates the teaching data based on the output of the first force sensor when the first claw portion is in the open / closed fixed state and the handle is gripped by the instructor.

2. The robot teaching device according to claim 1, a second force sensor that is installed between the robot and the second end effector and that is capable of measuring at least one of a force or a torque acting between the robot and the second end effector; a position and orientation measurement unit that measures at least one of the position and orientation of the first end effector; the teaching data is generated by the teaching data generation unit based on an output of the position and orientation measurement unit and an output of the first force sensor, and a robot control unit controls the robot based on at least one of the position and orientation of the second end effector and the output of the second force sensor, The second end effector A robot teaching device characterized by having a second claw portion that is opened and closed by power from the robot and has a gripping structure that is at least partially the same as the gripping structure of the first claw portion.

3. The robot teaching device according to claim 2, a calibration jig, the calibration jig being fixed so that at least one of the position and the orientation can be measured by the position and orientation measurement unit and the position and the orientation of the first claw portion and the second claw portion are uniquely determined with respect to the gripping structure; a first coordinate system calibration unit that calculates a first transformation matrix for converting at least one of the position and orientation of the first end effector and at least one of the force and torque measurement values ​​of the first force sensor into data expressed in a reference coordinate system defined in association with the gripping structure, based on results of simultaneously measuring at least one of the position and orientation of the calibration jig fixed to the first jaw portion, at least one of the position and orientation of the first end effector, and at least one of the force and torque output from the first force sensor; a second coordinate system calibration unit that calculates a second transformation matrix for transforming at least one of the position and orientation of the second end effector and at least one of the force and torque measurement values ​​of the second force sensor into data expressed in the reference coordinate system defined in association with the gripping structure, based on results of simultaneously measuring at least one of the position and orientation of the calibration jig fixed to the second jaw portion, at least one of the position and orientation of the second end effector, and at least one of the force and torque output from the second force sensor; The teaching data generation unit converting, using the first transformation matrix, at least one of the position or orientation of the first end effector and at least one of the force or torque measurement values ​​of the first force sensor into teaching data of at least one of the position or orientation and at least one of the force or torque expressed in the reference coordinate system; The robot control unit A robot teaching device characterized in that, using the second transformation matrix, at least one of the position or posture of the second end effector and at least one of the force or torque measurement values ​​of the second force sensor are converted into at least one of the position or posture and at least one of the force or torque data expressed in the reference coordinate system, and these data are made to follow at least one of the position or posture and / or at least one of the force or torque of the teaching data.

4. The robot teaching device according to claim 3, The first transformation matrix and the second transformation matrix are each a position transformation matrix for transforming at least one of the position and the orientation; a force transformation matrix that transforms at least one of force and torque; The first coordinate system calibration unit and the second coordinate system calibration unit each include: A robot teaching device characterized in that the force transformation matrix is ​​calculated based on data on at least one of the force and torque applied to the calibration jig.

5. The robot teaching device according to claim 4, A robot teaching device characterized in that at least one of a force or a torque applied to the calibration jig is calculated based on the weight of the calibration jig and the position of the center of gravity of the calibration jig as viewed from the reference coordinate system.

6. The robot teaching device according to claim 4, A robot teaching device, wherein the calibration jig is provided with a third force sensor that measures at least one of a force and a torque applied to the calibration jig.

7. The robot teaching device according to claim 3, a reference coordinate system setting unit that sets the reference coordinate system; an impedance characteristic setting unit that sets a target impedance characteristic for the difference between at least one of the position or posture of the teaching data and at least one of the position or posture of the second end effector expressed in the reference coordinate system.

8. The robot teaching device according to claim 1, The first end effector an information processing unit that acquires a measurement value of the first force sensor and transmits the measurement value to an external device by wireless communication; a battery that supplies power to the first force sensor and the information processing unit.

9. The robot teaching device according to claim 1, The first end effector an opening / closing mechanism that opens and closes the first claw portion; an opening / closing operation unit that opens and closes the opening / closing mechanism of the first claw unit; an opening / closing fixing mechanism that fixes the opening / closing mechanism of the first claw portion in an open / closed state, The robot teaching device is characterized in that the open / close locking mechanism switches between the openable / closeable state and the open / close locked state of the first claw portion.

Images