JP2014018878A - Robot system, and robot control device and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a robot system and a robot control device, which enable calibration to be performed simply and accurately.SOLUTION: A robot control part of the robot system: causes a robot to perform a touch sensing operation for causing a fingertip tool to contact with a target point set on a workpiece surface along a touch sensing locus generated on the same virtual space as a working locus; calculates a correction amount of a reference coordinate system on the basis of a first position and posture data respectively representing the position and posture of a tool center point of the fingertip tool at a contact point at which the fingertip tool contacts with the workpiece at the target point, the position and posture being detected at the touch sensing operation, and on the basis of a second position and posture respectively representing the position and posture of the tool center point at each target point assumed when moving the fingertip tool along the touch sensing locus; corrects the reference coordinate system on the basis of the calculated correction amount; and, when the workpiece is worked, controls the robot so as to move the fingertip tool along the working locus with the corrected reference coordinate system as reference.

Description

  The present invention relates to a robot system, a robot control apparatus, and a method, and is suitably applied to a robot system that processes a workpiece (processing object) by a robot having an articulated robot arm, for example.

  In this type of robot system, when a trajectory (hereinafter referred to as a processing trajectory) of the hand tool attached to the tip of the robot arm at the time of the above processing is generated off-line from a CAD (Computer Aided Design) model, the CAD model It is necessary to calibrate the machining trajectory created in space according to the actual position and posture of the workpiece.

  Conventionally, such calibration is performed by causing a robot to measure a table coordinate system fixed on an actual table by a teaching operation using a shape feature such as a corner of a table holding a workpiece. It has been broken.

  According to such a conventional calibration method, the relative position between the reference coordinate system on the CAD model and the work is based on the table coordinate system fixed on the real table and the relative position of the real work. Can be combined. That is, by generating a machining trajectory in the CAD model space on the basis of the table coordinate system and teaching the table coordinate system in the real space, the relative positions of the machining trajectory and the actual workpiece can be matched.

  However, there is also a problem that it is difficult to perform highly accurate alignment by the teaching operation as described above. Therefore, in recent years, the present patent applicant has measured the position of the work of the hand tool by touch sensing on a work having three orthogonal planes, and corrects the relative position between the hand tool and the jig based on the measurement result. Has been proposed (Patent Document 1). Here, touch sensing refers to a technique for measuring the position of a workpiece by pressing a hand tool attached to the tip of the robot arm of the robot against the surface of the workpiece.

JP 2011-152599 A

  By the way, in this patent document 1, when the workpiece does not have three planes orthogonal to each other, three planes orthogonal to a jig such as a table for fixing the workpiece are provided, and the data obtained by the touch sensing operation with respect to the three planes is provided. Calibrating based on this is disclosed.

  However, according to the calibration method disclosed in Patent Document 1, if the workpiece does not have three orthogonal planes, calibration is performed using measurement data at a location away from the workpiece. The robot with low positioning accuracy has a problem that the accuracy of calibration is low.

  The present invention has been made in consideration of the above points, and an object of the present invention is to propose a robot system, a robot control apparatus, and a method that can perform calibration easily and accurately.

  In order to solve such a problem, in the present invention, in a robot system, a robot in which a first hand tool for processing or a second hand tool for measurement is attached to a tip portion of a robot arm, and during processing of a workpiece, A robot controller for controlling the position and orientation of the robot so as to move the tool center point of the first hand tool along a machining trajectory created with reference to a reference coordinate in a virtual space; The control unit performs a touch sensing operation of bringing the second hand tool into contact with a target point set on the surface of the workpiece along a touch sensing trajectory created on the same virtual space as the machining trajectory. The second hand tool touches the workpiece at the target point detected by the robot and detected during the touch sensing operation. This is assumed when the first position and orientation data representing the position and orientation of the tool center point of the second hand tool at the contact point and the second hand tool are moved along the touch sensing trajectory. Based on the second position and posture data representing the position and posture of the tool center point when the second hand tool touches the workpiece at the target point, the workpiece and the reality in the virtual space A correction amount of the reference coordinate system for matching the workpiece is calculated, the reference coordinate system is corrected based on the calculated correction amount, and the corrected reference coordinate system is calculated during the processing of the workpiece. The robot is controlled so as to move the tool center point of the first hand tool along the reference processing trajectory.

  In the present invention, the reference coordinates in the virtual space are processed at the time of workpiece processing with a robot to which the first hand tool for machining or the second hand tool for measurement is attached at the tip of the robot arm being controlled. In the robot control apparatus for controlling the position and posture of the robot so as to move the tool center point of the first hand tool along the machining trajectory created with reference to Causing the robot to perform a touch sensing operation for bringing the second hand tool into contact with a target point set on the surface of the workpiece along the created touch sensing trajectory, and detecting the touch sensing operation, The tool center position of the second hand tool at the contact point where the second hand tool contacts the workpiece at the target point. First position and posture data representing the position and posture of the robot, and the second hand tool at the target point assumed when the second hand tool is moved along the touch sensing trajectory. The reference coordinates for matching the workpiece in the virtual space with the actual workpiece based on the second position and posture data representing the position and posture of the tool center point when contacting the workpiece A correction amount of the system is calculated, the reference coordinate system is corrected based on the calculated correction amount, and when the workpiece is processed, the first movement is performed along the processing trajectory with the corrected reference coordinate system as a reference. The robot is controlled to move the tool center point of the hand tool.

  Furthermore, in the present invention, a robot in which the first hand tool for processing or the second hand tool for measurement is attached to the tip of the robot arm, and the reference coordinates in the virtual space are used as a reference when processing the workpiece. In the robot control method in a robot system having a robot control unit for controlling the position and posture of the robot so as to move the tool center point of the first hand tool along the created machining trajectory, the robot control unit The robot performs a touch sensing operation for bringing the second hand tool into contact with a target point set on the surface of the workpiece along a touch sensing trajectory created in the same virtual space as the machining trajectory. A first step to be executed; and the target point detected by the robot control unit during the touch sensing operation. In the above, the first position and orientation data representing the position and orientation of the tool center point of the second hand tool at the contact point where the second hand tool has contacted the workpiece, and the second hand tool are Second position and posture data representing the position and posture of the tool center point when the second hand tool comes into contact with the workpiece at the target point, assumed when moved along a touch sensing trajectory And a second step of calculating a correction amount of the reference coordinate system for matching the work in the virtual space with the actual work, and the robot control unit calculates the correction amount. And a third step of correcting the reference coordinate system based on the above, and before the robot control unit uses the corrected reference coordinate system as a reference when processing the workpiece. It was provided and a fourth step of controlling the robot to move the tool center point of the first hand tool along the machining trajectory.

  Therefore, according to the robot system and the robot control apparatus and method of the present invention, it is possible to calibrate the machining trajectory without using a dedicated jig for a workpiece to be processed in any shape. In addition, since calibration is performed based on the position and orientation of the tool center point when the hand tool actually contacts the workpiece during the touch sensing operation, calibration with high accuracy can be performed.

  According to the present invention, it is possible to realize a robot system, a robot control apparatus, and a method that can perform calibration easily and accurately.

It is a basic diagram which shows schematic structure of the robot system by this Embodiment. It is a conceptual diagram with which it uses for description of the calibration function by this Embodiment. It is a conceptual diagram with which it uses for description of a tool center point. It is a conceptual diagram with which it uses for description of the calibration function by this Embodiment. It is a conceptual diagram with which it uses for description of the calibration function by this Embodiment. It is a flowchart which shows the process sequence of a calibration process.

  Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

(1) Configuration of Robot System According to this Embodiment In FIG. 1, reference numeral 1 denotes a robot system according to this embodiment as a whole. The robot system 1 includes a robot 4 that performs a predetermined processing such as deburring on a workpiece 3 fixed to a table 2, and a robot control unit 5 that controls the operation of the robot 4.

  The robot 4 includes an articulated robot arm 11 installed on a base 10, and a force sensor 13 is fixed to the tip of the robot arm 11 via a flange portion 12. Further, a hand tool 15 is attached to the force sensor 13 through a spindle motor 14 so that the hand tool 15 can be exchanged. The force sensor 13 can be detected. When the force sensor 13 detects such a load, the force sensor 13 outputs a sensor signal having a voltage level corresponding to the magnitude of the load.

  The robot control unit 5 includes a control device 6 and a controller 7. The control device 6 is a computer device that includes information processing resources such as a CPU (Central Processing Unit) 20 and a memory 21, and is composed of, for example, a personal computer. The control device 6 uses the tool center point (TCP: Tool Center Point) machining trajectory data of the hand tool created offline using a three-dimensional CAD device (not shown) and the sensor signal output from the force sensor 13. Then, the motion trajectory of the robot 4 is calculated based on the position and orientation data representing the position and orientation of the robot 4 sequentially given from the controller 7, and the trajectory data of the motion trajectory of the robot 4 obtained by such calculation is used as the controller 7. To send.

  The controller 7 is a computer device that includes information processing resources such as the CPU 22 and the memory 23, similarly to the control device 6, and is composed of, for example, a personal computer. The controller 7 controls the position and posture of the robot 4 based on the trajectory data of the motion trajectory of the robot 4 given from the control device 6 so that the robot 4 operates on the motion trajectory according to the trajectory data.

(2) Calibration Function According to this Embodiment Next, the calibration function installed in the robot system 1 will be described. The robot system 1 is equipped with a calibration function for calibrating the trajectory (processing trajectory) of the tool center point of the hand tool at the time of processing the workpiece 3 created in advance by an operator. This calibration function detects a deviation amount between the workpiece 3 on the CAD model space (virtual space) in which the machining trajectory is created and the actual workpiece 3 by a touch sensing operation, and the machining trajectory is based on the detection result. It is a function to correct.

In practice, in the robot system 1, when the operator creates a machining trajectory in the CAD model space offline using a three-dimensional CAD device, the hand tool 15 (hereinafter referred to as a measurement pin) used during the touch sensing operation described above is used. A trajectory for the tool center point to move (hereinafter referred to as a touch sensing trajectory) is generated in the same CAD model space. That is, as shown in FIG. 2 describes a touch sensing trajectory OR ₁ and machining trajectory OR _2, a relative position from the same frame of reference sigma _CAD set on CAD model space. Reference coordinate system Σ _CAD at this time, it may be anywhere. The reference coordinate system of the touch sensing trajectory OR ₁ may be provisionally determined based on the layout design data.

Before the workpiece 3 is processed, the target pins P _{1 to} P ₄ set on the surface of the workpiece 3 are moved by moving the measurement pin along the touch sensing trajectory OR ₁ created as described above. A touch sensing operation for contacting the measurement pin is executed, and the position and orientation of the tool center point of the measurement pin at the time when the measurement pin actually contacts the surface of the workpiece 3 are measured. As shown in FIGS. 1 and 3, the position and orientation of the tool center point means a coordinate system (hereinafter referred to as a robot coordinate system) Σ _R (fixed on the base 10 of the robot 4). A coordinate system Σ _CAD is set on the space (as a reference), and the coordinate system (tool center point coordinate system) Σ _TCP with the tool center point TCP as the origin relative to this coordinate system Σ _CAD is the position and orientation of the _TCP .

At this time, as shown in FIG. 4, when the position and orientation of the workpiece 3 ′ in the CAD model space and the actual position and orientation of the workpiece 3 are misaligned (do not match), the measurement pin is actually the workpiece 3 position and attitude of the tool center point of the measuring pin when in contact with the surface is offset from the position and orientation of the tool center point that has been assumed in the touch sensing trajectory oR ₁ on the CAD model space.

Therefore, as shown in FIG. 5, the position and orientation of the tool center point of the measurement pin when the measurement pin actually contacts the workpiece 3 at one or a plurality of target points P _{1 to} P ₄ during the touch sensing operation, by correcting the reference coordinate system sigma _CAD based on the shift amount of the position and orientation of the measurement pin when the envisaged when moving the measuring pin along the touch sensing track oR _1, CAD model space The correction reference coordinate system _{ΣCAD ′ in} which the workpiece 3 ′ and the actual workpiece 3 are matched is calculated. When the workpiece 3 is processed, the robot 4 is controlled so as to move the hand tool 15 along the processing path OR ₂ with the correction reference coordinate system _{ΣCAD ′} obtained in this way as a reference.

  Hereinafter, such a calibration function will be described more specifically.

  First, the operator performs touch sensing including the position and orientation of the tool center point of the measurement pin when the measurement pin contacts the surface of the workpiece 3 at each target point, and the normal direction vector of the surface at that point. The trajectory is generated on the same CAD model space as the machining trajectory. The touch sensing trajectory is created so that the measurement pin approaches the target point on the surface of the work 3 from a point away from the work 3 by a certain distance. At this time, position and orientation data representing the position and orientation of the tool center point of the measurement pin when the measurement pin contacts the workpiece 3 at each target point in an ideal state with no workpiece error is calculated.

  During the touch sensing operation, the force sensor 13 detects a reaction force that the measurement pin receives from the work 3 when the measurement pin comes into contact with one target point on the surface of the work 3, and the force sensor 13 detects the reaction force. The position and orientation data representing the position and orientation of the tool center point of the measuring pin at the time of detecting is acquired. Such a position and posture of the tool center point can be calculated based on the position and posture of the robot 4 acquired from the robot 4 by the controller 7.

  Measurement of the position and orientation of the tool center point of the measuring pin by touch sensing as described above is executed at each target point set on the surface of the workpiece 3, and the tool center point of the measuring pin at each individual target point is executed. The position and orientation data representing the position and orientation are stored.

Then, the calculated position and orientation data, based on the position and orientation data obtained by the touch sensing operation as described above, calculates the correction amount of the reference coordinate system sigma _CAD (translation amount and rotation amount). As such a correction amount, when the target point is less than three points, only the translation amount is calculated, and when the target point is three points or more (more precisely, three or more points that are not aligned in a straight line are included). Calculates the amount of translation and the amount of rotation.

Here, of the correction amount of the reference coordinate system Σ _CAD , the translation amount is the point at which the measurement pin actually contacts the surface of the workpiece 3 with respect to each target point (hereinafter referred to as a measurement point). It can be calculated as the translation amount of the center of gravity of the tool center point of the measurement pin. For example, assuming that there are N (N> 1) target points, the positions of tool center points of measurement pins at these target points (hereinafter referred to as target point TCP positions) ^CAD p _TCPk
Where k = 1 to N
_Then , the center of gravity ^CAD p _G of the aggregate of the target point TCP position ^CAD p _TCPk is
Is calculated by

In the equations (1) and (2), the upper left subscript represents the reference coordinate system. Therefore, ^CAD p _{TCPk in} equation (1) represents the position of the tool center point of the measurement pin at the target point p _TCPk with reference to the reference coordinate system in the CAD model space, and ^CAD p _G in equation (2) It represents the position of the center of gravity position p _G collection of target point TCP position ^CAD p _TCPk relative to the reference coordinate system. The same applies to the following.

Also, the position of the tool center point of the measurement pin at the actual measurement point for each target point TCP position ^CAD p _TCPk (hereinafter referred to as the measurement point TCP position) ^CAD p _{TCPk ′}
Where k = 1 to N
Then, the center of gravity ^CAD p _G ′ of the assembly of the measurement point TCP position ^CAD p _TCPk ′ is
Is calculated by

Therefore, the translation component ^CAD p _{p → p ′ in} the correction amount of the reference coordinate system Σ _CAD described above is the centroid position ^CAD p _G expressed by the expression (2) and the centroid position expressed by the expression (4). ^As the difference from ^CAD p _G ′,
Can be calculated.

On the other hand, each target point TCP position ^CAD p _TCPk
Where k = 1 to N
And each measurement point TCP position ^CAD p _TCPk '
Where k = 1 to N
_Then , the relationship between these target point TCP position ^CAD p _TCPk and the measurement point TCP position ^CAD p _TCPk ′ is as follows:
It can be expressed as. In this equation (8), ^CAD' R _CAD is a rotation matrix representing the rotation component of the correction amount of the reference coordinate system sigma _CAD described above.

In this case, solution satisfying the number of target points is sufficiently large to equation (8) is normally not present, the rotation component of the correction amount of the reference coordinate system sigma _CAD can calculate a least squares approximate solution by the following equation .

However, the least square approximation solution calculated by the equation (9) is not necessarily a rotation matrix. For example, there is a possibility of including enlargement or reduction in the axial direction, and the matrix becomes a 3 × 3 matrix that minimizes the square error between X and Y. Therefore, the singular value decomposition is
And In equation (10), S represents a matrix in which eigenvalues are arranged diagonally, and U represents a left singular matrix. Therefore, the rotation matrix of the least square approximation solution is
Can be calculated.

Following equation homogeneous transformation matrix ^CAD' T _CAD for correcting from the above, the reference coordinate system sigma _CAD to correct the reference coordinate system sigma _CAD'
Then, the reference coordinate system Σ _CAD based on the robot coordinate system Σ _R (FIG. 3) is a corrected reference coordinate system based on the robot coordinate system Σ _R based on the _homogeneous transformation matrix ^R T _{CAD ′} given by the following equation. It is corrected to _ΣCAD´ .

(3) Calibration Processing Here, the calibration processing as described above is performed by the control of the CPU 20 of the control device 6 according to the processing procedure shown in FIG. 6 based on a control program (not shown) stored in the memory 21 of the control device 6. To be done.

  Prior to this, the operator creates a CAD model of the work 3 in the CAD model space using a three-dimensional CAD device. The operator then takes the CAD model of the workpiece 3 created as described above into a general CAM (Computer Aided Manufacturing) or a robot CAM, and uses this CAM to process the workpiece 3 during processing. The tool center point trajectory (machining trajectory) of the hand tool 15 and the tool center point trajectory (touch sensing trajectory) of the measurement pin during the touch sensing operation are created in the same CAD model space. Next, the operator fixes the work 3 on the table 2 in a predetermined state, and then operates the control device 6 so as to start the calibration process of FIG.

  When such operation is performed, the CPU 20 of the control device 6 starts the calibration process shown in FIG. 6. First, based on the trajectory data of the touching sensing trajectory created using the CAM as described above, the measurement pin is set. The robot 4 is controlled to move to a position before the first target point set on the surface of the workpiece 3 (SP1).

  Subsequently, the CPU 20 causes the robot 4 to start the operation of pressing the measurement pin against the target point (SP2), and thereafter, based on the sensor signal given from the force sensor 13, the measurement pin of the robot 4 is the workpiece 3 Wait for contact with the surface (SP3: NO).

  When the CPU 20 eventually detects that the measurement pin of the robot 4 has come into contact with the surface of the workpiece 3 based on the sensor signal output from the force sensor 13 (SP3: YES), then the CPU 20 gives the current time given from the controller 7 Based on the position and orientation data representing the position and orientation of the robot 4, position and orientation data representing the position and orientation of the tool center point of the measurement pin are calculated and stored (SP4).

  Next, the CPU 20 determines, based on the trajectory data of the touching sensing trajectory, whether or not the processing of step SP1 to step SP4 has been completed for all target points set on the surface of the workpiece 3 (SP5). .

  If the CPU 20 obtains a negative result in this determination, it returns to step SP1 (SP5: NO), and then repeats the processing of step SP1 to step SP5 while sequentially switching the target point to another target point.

And CPU20 will complete | finish the process of step SP1-step SP5 about all the target points set on the surface of the workpiece | work 3 before long (SP5: YES), By (5) Formula and (11) mentioned above, correction amount of the reference coordinate system sigma _CAD (the translation amount and rotation amount) is calculated (SP6).

Further CPU20 utilizes the correction amount calculated in step SP6 (13) corrects the reference coordinate system sigma _CAD by formula (SP7), and thereafter ends this calibration process.

Incidentally, CPU 20 is in the processing to be executed after this, the machining orbit relative to the corrected reference coordinate system sigma _CAD' obtained by correcting the reference coordinate system sigma _CAD in step SP7 of the end tool 15 Tool The operation of the robot 4 is controlled via the controller 7 so that the center point moves.

(4) Effects of this Embodiment According to the robot system 1 having the above-described configuration, since three planes orthogonal to the calibration process are not required, a dedicated jig can be used for a workpiece to be processed in any shape. The machining trajectory can be calibrated without using.

Further, in the robot system 1, since calibration is performed using measurement data (position and orientation data representing the position and orientation of the measurement pin) acquired in the vicinity of the processing location, calibration with high accuracy can be performed. That is, the calibration technique used conventionally, a reference coordinate system sigma _CAD in CAD model space, but is intended to match the reference coordinate system of the real space, the calibration technique of the present embodiment CAD model work 3'of space (Figure 3), to match the workpiece 3 in the real space as corrected reference coordinate system sigma _CAD in the CAD model space, it is to calibrate the machining trajectory as a result. Therefore, as a result the coordinate system of the reference coordinate system sigma _CAD and the real space of the CAD model space sometimes will deviate rather but create machining trajectory in real space relative to the workpiece 3 'on the CAD model space It is possible to approach the machined track with extremely high accuracy.

  Therefore, according to the robot system 1, calibration can be performed easily and accurately.

  Incidentally, in this robot system 1, the measurement pin used at the time of the touch sensing operation has the same shape as the hand tool 15 used at the time of the processing of the workpiece 3, and the posture of the measurement pin at the time of the touch sensing operation is changed to the hand tool 15 at the time of the processing. By adopting the same posture as this, it is possible to obtain an effect that the creation of the touch sensing trajectory can be facilitated. In this way, when the robot system 1 is designed in this way, the robot 4 is only selected and arranged so that the robot 4 can move the tool center point of the hand tool 15 along the machining path. This is because it is guaranteed that the touch sensing operation can be performed.

(5) Other Embodiments In the above-described embodiment, the case where the present invention is applied to the robot system 1 configured as shown in FIG. 1 has been described. However, the present invention is not limited to this. Further, the present invention can be widely applied to robot systems having various configurations other than generating the processing trajectory of the hand tool 15 at the time of workpiece processing offline using a three-dimensional CAD device.

  In the above-described embodiment, the case where the force sensor 13 is applied as a sensor for detecting that the hand tool 15 is in contact with the workpiece 3 during the touch sensing operation has been described. In addition to the force sensor, a contact sensor or a non-contact sensor may be used. For example, a non-contact distance sensor or a power switch may be used.

  Furthermore, in the above-described embodiment, the case where the robot control unit 5 that controls the operation of the robot 4 is configured by the control device 6 and the controller 7 has been described. However, the present invention is not limited to this, and these control devices 6 and the controller 7 may be integrated.

Further, in the above-described embodiment, the reference coordinate system Σ in the CAD model space using the least square method based on the position and orientation data representing the position and orientation of the tool center point of the measurement pin acquired by the touch sensing operation. _{Although the case where the CAD} correction amount is obtained has been described, the present invention is not limited to this. For example, the correction amount may be obtained sequentially by the least square method.

Further, in the aforementioned embodiment, it has dealt with the case where to obtain the correct reference frame sigma _CAD' obtained by correcting the reference coordinate system sigma _CAD in CAD model space only once, the present invention is not limited thereto , to perform repeated a plurality of times for example may be corrected correction reference coordinate system sigma _CAD' as in the reference coordinate system sigma _CAD, against further similar corrected correction reference coordinate system sigma _CAD' May be. By doing so, calibration can be performed with higher accuracy.

  The present invention can be widely applied to a robot system that processes a workpiece by a robot having, for example, a multi-joint robot arm and generates a processing trajectory of a hand tool offline during the workpiece processing.

  DESCRIPTION OF SYMBOLS 1 ... Robot system, 3 ... Work, 4 ... Robot, 5 ... Robot control part, 6 ... Control apparatus, 7 ... Controller, 13 ... Force sensor, 15 ... Hand tool, 20 ... CPU, 21 ... Memory.

Claims (7)

A robot in which a first hand tool for processing or a second hand tool for measurement is attached to the tip of the robot arm;
A robot control unit that controls the position and orientation of the robot so as to move the tool center point of the first hand tool along a machining trajectory created with reference to a reference coordinate in a virtual space during machining of the workpiece And
The robot controller is
Causing the robot to perform a touch sensing operation of bringing the second hand tool into contact with a target point set on the surface of the workpiece along a touch sensing trajectory created in the same virtual space as the machining trajectory ,
First position and orientation data representing the position and orientation of the tool center point of the second hand tool at the contact point at which the second hand tool touches the workpiece at the target point detected during the touch sensing operation. And the position of the tool center point when the second hand tool contacts the workpiece at the target point, which is assumed when the second hand tool is moved along the touch sensing path, and Based on the second position and posture data representing the posture, a correction amount of the reference coordinate system for matching the workpiece in the virtual space with the actual workpiece is calculated,
Correcting the reference coordinate system based on the calculated correction amount;
Wherein the robot is controlled so as to move a tool center point of the first hand tool along the machining trajectory with the corrected reference coordinate system as a reference at the time of machining the workpiece. . A plurality of the target points are set on the surface of the workpiece,
The robot controller is
2. The robot system according to claim 1, wherein the correction amount of the reference coordinate system is calculated by a least square method based on the first and second position and orientation data for each target point. The first and second hand tools are formed in the same shape,
The robot controller is
The robot is controlled such that the posture of the second hand tool during the touch sensing operation is the same as the posture of the first hand tool during the machining process. Item 3. The robot system according to Item 2. Created with reference to the reference coordinates in the virtual space at the time of workpiece processing, with a robot to which the first hand tool for processing or the second hand tool for measurement is attached at the tip of the robot arm as a control target In a robot control apparatus for controlling the position and posture of the robot so as to move a tool center point of the first hand tool along a processing path,
Causing the robot to perform a touch sensing operation of bringing the second hand tool into contact with a target point set on the surface of the workpiece along a touch sensing trajectory created in the same virtual space as the machining trajectory ,
First position and orientation data representing the position and orientation of the tool center point of the second hand tool at the contact point at which the second hand tool touches the workpiece at the target point detected during the touch sensing operation. And the position of the tool center point when the second hand tool contacts the workpiece at the target point, which is assumed when the second hand tool is moved along the touch sensing path, and Based on the second position and posture data representing the posture, a correction amount of the reference coordinate system for matching the workpiece in the virtual space with the actual workpiece is calculated,
Correcting the reference coordinate system based on the calculated correction amount;
In the processing of the workpiece, the robot is controlled to move a tool center point of the first hand tool along the processing trajectory with the corrected reference coordinate system as a reference. apparatus. A robot in which a first hand tool for machining or a second hand tool for measurement is attached to the tip of the robot arm, and a machining trajectory created with reference to the reference coordinates in the virtual space during workpiece machining A robot control method in a robot system having a robot controller that controls a position and a posture of the robot so as to move a tool center point of the first hand tool along
Touch sensing operation in which the robot control unit makes the second hand tool contact a target point set on the surface of the workpiece along a touch sensing trajectory created in the same virtual space as the machining trajectory A first step of causing the robot to execute:
The robot control unit detects the position and orientation of the tool center point of the second hand tool at the contact point where the second hand tool contacts the workpiece at the target point, which is detected during the touch sensing operation. 1 position and orientation data, and when the second hand tool contacts the workpiece at the target point, which is assumed when the second hand tool is moved along the touch sensing path. Based on the second position and orientation data representing the position and orientation of the tool center point, a correction amount of the reference coordinate system for matching the workpiece in the virtual space with the actual workpiece is calculated. Two steps,
A third step in which the robot controller corrects the reference coordinate system based on the calculated correction amount;
The robot control unit controls the robot to move the tool center point of the first hand tool along the machining trajectory with the corrected reference coordinate system as a reference when machining the workpiece. A robot control method comprising: 4 steps. A plurality of the target points are set on the surface of the workpiece,
In the second step, the robot control unit
The robot control method according to claim 5, wherein the correction amount of the reference coordinate system is calculated by a least square method based on the first and second position and orientation data for each target point. The first and second hand tools are formed in the same shape,
In the first step, the robot control unit
The robot is controlled such that the posture of the second hand tool during the touch sensing operation is the same as the posture of the first hand tool during the processing. Item 7. The robot control method according to Item 6.