JP6462986B2 - Robot control method, article manufacturing method, and control apparatus - Google Patents

Description

The present invention is a robot control method to calibrate the point of interest coordinates system to the point of interest that is set based on the tip coordinate system origin is set to the end of the robot arm as the origin for controlling the robot arm, the production of goods article The present invention relates to a method and a control device .

  In recent years, a robot apparatus has been developed that uses a robot to perform assembling imitating human movement. This type of robot is configured by attaching a tool such as a robot hand to the tip of an articulated robot arm. In addition, a control device is connected to the robot, and an input device that operates the robot and sets teaching points in the control device is connected to the control device.

  As a method for designating the robot operation, there are a method for moving between teaching points indicating a designated position and posture, and a method for performing a shift operation for moving the tip of the robot with a designated movement amount in a designated direction from the teaching point. is there. For example, when inserting a part gripped by a robot hand into an annular part, specify the teaching point at the hole entrance of the annular part, specify the direction and distance from the hole entrance to the back of the hole, and specify from the teaching point A shift operation that moves the tip of the robot by the amount of movement is used.

  The teaching point is represented by a parameter having six pieces of information, that is, three pieces of distance information representing the position from the origin of the reference coordinate system and three pieces of angle information representing the posture. In the operation of setting the teaching point in the control device (teaching operation), the robot is operated by an input device such as a teaching pendant, and parameters are acquired at a target position and posture.

The robot tip shift operation is performed on the basis of a point-of-interest coordinate system whose origin is a point of interest that can be arbitrarily set by the user. In general, a tool center point (Tool Center Point: TCP) set in the tool or in the vicinity of the tool is used as the attention point, and a coordinate system having TCP as the origin is generally called a tool coordinate system Σ _tcp . The TCP is a parameter having six pieces of information, that is, three distance information representing a position represented by a tip coordinate system (so-called flange coordinate system) Σ _ef with the tip of the robot arm as an origin, and three angle information representing the posture. is there.

  At this time, if there is no inclination between the robot arm and the tool, the shift operation direction moves straight from the teaching point to the final arrival position, so that the insertion operation is performed. However, the tool may be inclined with respect to the robot arm due to the weight of the tool, the weight of the part gripped by the tool, the mounting error between the robot arm and the tool, or the like.

  If the tool is tilted with respect to the robot arm, when the robot arm is moved to the work start position and posture, the TCP is displaced from the teaching point in the real space. If the robot arm is moved in the shift operation direction in this state, the TCP may reach a position shifted from the target final arrival position, and the insertion operation may not be achieved.

Therefore, conventionally, the tool coordinate system Σ _tcp has been calibrated using the following technique. In Patent Document 1, a sensor for detecting contact and a jig having a known shape are used, and the sensor is brought into contact with three surfaces of the positioned jig to measure the shape and posture of the jig. those by calculating the difference of performing the calibration of the tool coordinate system sigma _tcp has been proposed. Patent Document 2 uses a sensor for measuring distance / displacement and a jig having a known shape, measures the distance / displacement to the known jig, and calculates the difference from the ideal state. A method for calibrating the tool coordinate system _Σtcp has been proposed. As described above, conventionally, various types of sensors are used, the calibration value is obtained by measuring the calibration jig, and the tool coordinate system _Σtcp is calibrated.

JP 2011-152599 A JP 2011-148045 A

  However, in the conventional calibration method of the tool coordinate system using the sensor, it is necessary to change the robot arm to a plurality of positions and postures in order to measure the periphery of the jig with the sensor. Therefore, a wide space in which the robot arm can take various positions and postures around the measurement place is required.

  However, in a robot apparatus in which a plurality of parts are assembled by a single robot, for example, a plurality of jigs and tools are often densely packed around the place to be measured. Therefore, in the conventional method, the jigs arranged around the robot arm become an obstacle to the robot arm that is operated when measuring, and a large space cannot be secured, and the calibration of the tool coordinate system is difficult.

  Accordingly, an object of the present invention is to calibrate a point-of-interest coordinate system without interfering with obstacles around the robot arm.

The present invention includes a reference coordinate system, a tip coordinate system with its origin at the end of the robot arm, the point of interest coordinates system to the tip coordinate system origin point of interest that is set based on, is defined, pre Symbol A design teaching point acquisition step for acquiring a design teaching point including distance information and angle information set based on the design data of the robot arm based on a reference coordinate system, and the position of the robot arm based on the design teaching point and attitude by adjusting the referenced to the reference coordinate system, the distance information and adjust the teaching point acquisition step of obtaining the adjustment taught point includes an angle information, based on the relative position of the adjusting teaching points with respect to the design taught point, preparative a predetermined direction relative to the said point of interest coordinates system after adjusting the position and orientation of the robot arm, to match the previous adjusted viewed in the reference coordinate system, calibrating the adjustment teaching point A calibration step of calibrating the point of interest coordinates system, the point of interest, after said robot arm is operated to move the adjustment teaching point after calibrating with the calibration step, it was calibrated with the calibration step And a step of controlling the operation of the robot arm so as to shift and move from the adjustment teaching point after being calibrated in the calibration step in the predetermined direction based on the subsequent point-of-interest coordinate system. It is characterized by.

  According to the present invention, the attention point coordinate system can be calibrated without the robot arm interfering with surrounding obstacles.

It is explanatory drawing which shows schematic structure of the robot apparatus which concerns on 1st Embodiment. It is a block diagram which shows the structure of the control apparatus of the robot apparatus which concerns on 1st Embodiment. It is a flowchart which shows the robot calibration method which concerns on 1st Embodiment. It is a side view which shows the state of the robot in each process of the robot calibration method which concerns on 1st Embodiment. It is a side view which shows the state of the robot in each process of the robot calibration method which concerns on 2nd Embodiment. It is a flowchart which shows the robot calibration method which concerns on 2nd Embodiment. It is a side view which shows the state of the robot in each process of the robot calibration method which concerns on 2nd Embodiment. It is a perspective view which shows the adjustment jig used for the robot calibration method using the robot apparatus which concerns on 3rd Embodiment.

  Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is an explanatory diagram showing a schematic configuration of the robot apparatus according to the first embodiment of the present invention. FIG. 1 (a) shows a robot apparatus for performing an insertion operation in which a workpiece is inserted into a workpiece insertion hole by a shift operation. The position and posture of a teaching point before workpiece insertion designated by a robot design value are shown. The state where the robot has moved is shown. FIG. 1B shows the position and posture of the robot adjusted by fine adjustment work.

  The robot apparatus 100 includes a robot 200 and a control apparatus 300 that is connected to the robot 200 and that controls the operation of the robot 200. The robot apparatus 100 includes an input device 400 that is connected to the control device 300 and functions as a teaching unit that teaches the operation of the robot 200 by a user operation.

  The robot 200 includes a multi-axis (for example, six axes) vertical articulated robot arm 201 and a robot hand 202 as a tool. The robot arm 201 is configured by connecting six links so as to be rotatable or pivotable at joints.

  The base end of the robot arm 201 is fixed to the upper surface (fixed surface) 101 </ b> A of the gantry 101. A robot hand 202 is attached to the flange surface 210 at the tip of the robot arm 201. The robot hand 202 has a plurality of (for example, three) fingers having joints, and grips or releases the workpiece 104 as an insert.

  The input device 400 is configured to be operable by the user, and edits or newly creates a parameter set in the control device 300 and outputs an operation command corresponding to the user's operation to the control device 300. The input device 400 is, for example, a teaching pendant or a handy terminal.

  The control device 300 controls the operation of the robot arm 201 and the robot hand 202 based on an operation command input from the input device 400 or a preset teaching point parameter. That is, the control device 300 stores parameters for operating the robot arm 201 and the robot hand 202, and the robot arm 201 and the robot hand 202 are controlled using these parameters.

  On the upper surface 101A of the gantry 101, a work fixing base 107, a work placing base 108, a parts supply base 109, and the like, which are objects to be inserted, are disposed. The work fixing base 107 is fixed to the upper surface 101 </ b> A of the base 101. A workpiece insertion hole 111 for inserting the workpiece 104 is formed in the workpiece fixing base 107. Around the work fixing base 107, work placing bases 108 and parts supply bases 109 are densely arranged locally, and the position and posture where the robot 200 can operate are limited.

  There are mainly three types of coordinate systems used to control the robot arm 201, and each plays a different role.

The first is a base coordinate system Σ ₀ whose origin is a point where the surface where the base end of the robot arm 201 is installed on the gantry 101 and the center of one axis of the robot arm 201 are orthogonal to each other. This base coordinate system Σ ₀ is used as a reference coordinate system of the robot arm 201 and cannot be edited by the user.

The second is a flange coordinate system Σ _ef as a tip coordinate system with the center of the flange surface 210 that is the tip of the robot arm 201 as the origin. This flange coordinate system Σ _ef is a coordinate system that always exists on the flange surface 210 regardless of the position and orientation of the robot arm 201, and is mainly used in the operation of the tip of the robot 200 for teaching work, and is edited by the user. Can not do.

The third is a tool coordinate system Σ _tcp as a point of interest coordinate system with a tool center point (TCP) as a point of interest that can be arbitrarily set by the user as an origin.

TCP is 6 of three distance information [X _tcp , Y _tcp , Z _tcp ] representing the position with respect to the origin of the flange coordinate system Σ _ef and three angle information [α _tcp , β _tcp , γ _tcp ] representing the posture. It is a parameter with one piece of information.

The tool coordinate system Σ _tcp is a coordinate system that exists in a place that always maintains a certain position and orientation from the flange surface 210 regardless of the position and orientation of the robot arm 201. The tool coordinate system Σ _tcp is mainly used for the operation of the tip of the robot 200 for teaching work and the designation of the shift operation direction. However, unlike the flange coordinate system Σ _ef , the coordinate system is based on TCP, which can be arbitrarily edited and newly added by the user using the input device 400, and is a coordinate system that can be edited depending on the application. The tool coordinate system _Σtcp is preferably set to the position and posture of the tip of the robot hand 202 as a tool and the tip of the workpiece 104 held by the robot hand 202.

In the first embodiment, the tool coordinate system _Σtcp is set at the tip of the workpiece 104. In other words, TCP is a parameter in which a design value of the distance from the flange surface 210 to the tip of the workpiece 104 gripped by the robot hand 202 is input.

Parameters indicating the target position and orientation of the TCP are stored in the control device 300 as teaching points W. The teaching point W refers to the position and orientation of the TCP, three distance information [X, Y, Z] representing the position relative to the origin of the base coordinate system Σ ₀ and three angle information [α, β, γ representing the orientation. ] Is a parameter calculated as

  The teaching point W in the first embodiment is a position and posture where TCP is made coincident with the design data of the position and posture before inserting the workpiece 104 as input parameters.

  That is, the teaching point W is a design teaching point obtained based on the design data of the robot arm 201 by a computer (not shown), for example, and is set to be a work start point (work start position and work start posture). ing.

The teaching point W is set with reference to a base coordinate system Σ ₀ that is a reference coordinate system. Hereinafter, a case where the control device 300 operates the robot arm 201 according to the teaching point W and then operates the robot arm 201 so that the TCP moves from the teaching point W in a predetermined direction based on the tool coordinate system _Σtcp. explain.

When TCP is the position and orientation of the teaching point W, which is the work start point, a final arrival position E that is an insertion target exists in the back of the workpiece insertion hole 111 on the straight line in the Z-axis direction of the tool coordinate system _Σtcp. doing. When the TCP is shifted by a predetermined movement distance from the teaching point W to the final arrival position E in the Z-axis shift operation direction 112, which is a predetermined direction with respect to the tool coordinate system _Σtcp , a straight line in the shift operation direction 112 is obtained. The tip of the robot 200 moves on the top.

  If there is no inclination A due to an assembly error or the like between the robot hand 202 and the flange surface 210, the center axis of the workpiece 104 and the center axis of the workpiece insertion hole 111 are coincident and moved in the shift operation direction 112. Since it moves to the final arrival position E, insertion becomes possible.

  However, for example, when there is an assembly error between the robot hand 202 and the flange surface 210, as shown in FIG. 1 (a), between the perpendicular direction to the flange surface 210 and the center line direction of the robot hand 202, Inclination A may occur. Note that the inclination A of the robot hand 202 with respect to the flange surface 210 may occur due to, for example, the weight of the robot hand 202 or the weight of the workpiece 104 gripped by the robot hand 202 in addition to the assembly error. In particular, when the occurrence of the inclination A is caused by the workpiece 104, the amount of inclination changes depending on the type (weight) of the workpiece 104 held by the robot hand 202.

  Therefore, in the first embodiment, as shown in FIG. 1B, a fine adjustment operation for matching the final arrival position E in the back of the workpiece insertion hole 111 on the straight line in the insertion direction 113 of the workpiece 104 is performed by the robot. This is performed by the user with the hand 202 holding the workpiece 104. This fine adjustment work is performed by the user operating the input device 400 to operate the robot arm 201.

This fine adjustment operation may be performed by adjusting the joint value of each axis of the robot arm 201, selecting the coordinate system, the position direction [X, Y, Z] of the selected coordinate system, and the rotation direction [R. Adjustment for moving the TCP may be performed by specifying the displacement amount of _{x 1} , R _y , R _z ].

A teaching point (adjustment teaching point) adjusted by fine adjustment work is used as a teaching point W ′, and the user operates the input device 400 and stores it in the control device 300. The teaching point W ′ is set with reference to a base coordinate system Σ ₀ that is a reference coordinate system.

By this fine adjustment operation, the position and posture of the robot arm 201 can be adjusted so that the final arrival position E coincides with the straight line in the insertion direction 113 of the workpiece 104. However, even if the shift operation in the direction of the Z axis of the tool coordinate system sigma _tcp in this position and orientation, since thereby move the shift operation direction 112 inclined slope A partial, in contact with the edge of the workpiece insertion hole 111 May not be inserted.

Therefore, in the first embodiment, in order to insert the workpiece 104 by the shift operation, the inclination A, that is, the tool coordinate system Σ _tcp is calibrated, and the tool coordinate system Σ _tcp is shifted with the insertion direction 113 of the workpiece 104. A coordinate system in which the directions 112 coincide is assumed.

Hereinafter, a case where the control device 300 calibrates the tool coordinate system Σ _tcp used for performing the shift operation will be described.

  FIG. 2 is a block diagram showing the configuration of the control device 300 of the robot device 100 according to the first embodiment of the present invention. The control device 300 includes an external input / output unit 301, a parameter storage unit 302, a trajectory calculation unit 303, a control command unit 304, and a calibration calculation unit 305.

  The external input / output unit 301 receives input of operation commands from the input device 400 and information such as parameter editing / new creation. The parameter storage unit 302 is a storage device, and information input from the external input / output unit 301 is stored in the parameter storage unit 302.

  Also, the external input / output unit 301 reads out the parameters stored in the parameter storage unit 302 and outputs them to the input device 400. The input device 400 displays the parameters input from the external input / output unit 301 on the screen.

  The trajectory calculation unit 303 reads parameters stored in the parameter storage unit 302, calculates a TCP trajectory based on the read parameters, and outputs displacement information of each axis of the robot arm 201 to the control command unit 304. . The control command unit 304 controls the position and orientation of the robot arm 201 based on the displacement information of each axis input from the trajectory calculation unit 303 and the current value information fed back from the robot arm 201. When calibration is necessary, the trajectory calculation unit 303 requests the calibration calculation unit 305 to perform calibration calculation.

  The calibration calculation unit 305 performs calibration based on the parameters stored in the parameter storage unit 302, stores the calibration result in the parameter storage unit 302, and reports the completion of calibration to the trajectory calculation unit 303. When the calibration is completed, the trajectory calculation unit 303 performs recalculation based on the calibration result stored in the parameter storage unit 302 and reflects it in the control of the robot arm 201.

Trajectory calculation unit 303 and the calibration calculating unit 305, for example, a computing device such as a CPU (arithmetic unit), by the CPU reads and executes the program from the storage device, the robot calibration method for calibrating the tool coordinate system sigma _tcp Each process of this is performed.

Next, a method for calibrating the tool coordinate system _Σtcp will be described. FIG. 3 is a flowchart showing the robot calibration method according to the first embodiment of the present invention. FIG. 4 is a side view showing the state of the robot in each step of the robot calibration method according to the first embodiment of the present invention.

In the first embodiment, it will be described in detail procedure for calibration of the tool coordinate system sigma _tcp using design taught point set by the value W, and the fine adjustment of the taught point W'Been.

First, the input device 400 outputs a TCP design value designated by a user operation to the external input / output unit 301. The external input / output unit 301 of the control device 300 inputs (acquires) a TCP design value from the input device 400 as a parameter setting operation necessary for controlling the robot arm 201. The TCP parameters input by the external input / output unit 301 are stored in the parameter storage unit 302. The calibration calculation unit 305 reads out and inputs (acquires) the TCP parameters stored in the parameter storage unit 302 from the parameter storage unit 302 (S1: attention point setting step). As described above, TCP is represented by parameters of position and orientation information [X _tcp , Y _tcp , Z _tcp , α _tcp , β _tcp , γ _tcp ] with respect to the origin of the flange coordinate system Σ _ef .

More specifically, in step S1, TCP is stored in the parameter storage unit 302 as a parameter P _tcp . The coordinate expression in the first embodiment will be described as Euler angle ZYX.

  [X, Y, Z] is position information and represents coordinates in each vector direction. [[Alpha], [beta], [gamma]] is posture information and represents a rotation angle in Euler angles.

The calibration calculation unit 305 calculates the position and orientation of the robot arm 201 by using the parameter P _tcp and substituting the parameter value into the 4 × 4 homogeneous transformation matrix T.

  Equations 2 to 4 below show formulas for calculating the homogeneous transformation matrix T. Note that n represents a parent-child relationship. For example, in the case of TCP, n is a symbol ef representing the parent flange surface 210, and n + 1 is a tcp representing a child TCP. This expresses the position and orientation.

  R shown in Equation 2 is a rotation matrix of 3 rows and 3 columns representing the posture, and is a simplified display of the matrix shown in Equation 3.

  Further, q shown in Equation 2 is a 3 × 1 position matrix representing the position, and is a simplified representation of the matrix shown in Equation 4.

Also, 0 shown in Equation 2 is a simplified display of a 0 matrix of 1 row and 3 columns. The calibration calculation unit 305 substitutes Equation 1 into Equations 2, 3, and 4 to calculate a TCP homogeneous transformation matrix _tcp ^ef T.

  Next, the input device 400 outputs the parameter of the teaching point W that is the position and posture before insertion designated by the user's operation (TCP is the work start point). The teaching point W is a design teaching point set based on design data such as the link length of the robot arm 201 so as to be a work start point. For example, the teaching point is obtained by offline teaching using a simulator such as a computer. Is a point. The external input / output unit 301 of the control device 300 inputs (acquires) the parameter of the teaching point W from the input device 400. The parameter of the teaching point W input by the external input / output unit 301 is stored in the parameter storage unit 302. The calibration calculation unit 305 reads and acquires the parameter of the teaching point W stored in the parameter storage unit 302 from the parameter storage unit 302 (S2: design teaching point acquisition step).

Teaching point W is a parameter P _w representing the position and orientation of the target TCP relative to the origin of the base coordinate system sigma _0, is stored in the parameter storage unit 302. Since the teaching point W is a design value, the teaching point W is a parameter that does not take into account the inclination A caused by an assembly error or the like.

The calibration calculation unit 305 substitutes Equation 6 into Equations 2, 3, and 4 to calculate the homogeneous transformation matrix _w ⁰ T of the teaching point W (the parent Σ ₀ is expressed as 0).

By using the TCP set in steps S1 and S2 and the teaching point W, the joint values [θ ^w ₁ , θ ^w ₂ , θ ^w ₃ , θ ^{w of the} axes of the robot arm 201 whose TCP matches the teaching point W are used. ₄ , θ ^w ₅ , θ ^w ₆ ] can be calculated by inverse kinematics calculation to determine the posture.

If TCP coincides with the teaching point W, the following homogeneous transformation matrix is obtained from the product of the homogeneous transformation matrix _{n + 1} ⁿ T of each axis of the robot 200 (1 to 6 axes are expressed as n = 1 to 6). A relationship is established.

  It is assumed that parameters such as link length and offset angle necessary for the homogeneous transformation matrix of each axis are stored in advance in the parameter storage unit 302.

In a robot having no assembly error in the ideal state, as shown in FIG. 4A, the shift operation direction 112 that moves in the Z direction of the tool coordinate system _Σtcp and the insertion direction 113 of the workpiece 104 coincide. Therefore, in the ideal state, when moving in the shift operation direction 112, it is possible to move straight to the final arrival position E, so there is no need to calibrate the tool coordinate system _Σtcp .

  However, in actuality, as shown in FIG. 4B, even if the robot arm 201 is operated based on the parameter of the teaching point W, the TCP is in real space due to the inclination A of the robot hand 202 due to an assembly error or the like. Move to a position and posture deviated from the upper work start point. In the state shown in FIG. 4B, the shift operation direction 112 is directed toward the final arrival position E. However, since the insertion direction 113 of the workpiece 104 is directed in a direction inclined by the inclination A, it is inserted. I can't. Therefore, in order to insert the workpiece 104 into the workpiece insertion hole 111, an operation for finely adjusting the inclination A is required.

  Therefore, first, the user operates the input device 400 to send a command to the control device 300 to operate the robot arm 201 based on the teaching point W. Thereby, the control command unit 304 of the control device 300 operates the robot arm 201 based on the parameter of the teaching point W as shown in FIG. Next, the user operates the input device 400 to send an operation command (an angle command for each joint or a command for the position and orientation of TCP) to the control device 300. The control command unit 304 of the control device 300 that has received the operation command operates the robot arm 201 in accordance with the operation command.

  That is, online teaching is performed in which the robot arm 201 is operated by the user operating the input device 400, and the position and posture of the TCP in the real space are finely adjusted by the user's visual observation. Prior to the adjustment, the position and posture of the robot arm 201 may be adjusted while directly observing by the user without performing an operation based on the teaching point W on the robot arm 201.

  In this way, by performing online teaching for adjusting the position and orientation of the robot arm 201 based on the teaching point W, the trajectory calculation unit 303 determines the teaching point (adjusted teaching point) from the adjusted position and orientation of the robot arm 201. W ′ is created (S3: adjustment teaching point acquisition step).

  In this step S3, the work 104 is grasped by the robot hand 202 as a grasping jig, and the position and posture of the work 104 grasped by the robot hand 202 are determined with respect to the work insertion hole 111 of the work fixing base 107. A point W ′ is obtained. In addition, although the gripping jig is the actual workpiece 104 to be assembled in the workpiece insertion hole 111, the gripping jig may be a standard device having the same shape as the workpiece 104 or a shape that can be regarded as the workpiece 104.

  That is, the user operates the robot arm 201 with the input device 400, and the control device 300 finely adjusts the position and posture of the robot arm 201 to the work start point before inserting the workpiece, and finely adjusts by the save command acquired from the input device 400. The subsequent teaching point W ′ is created.

  Specifically, the external input / output unit 301 outputs a storage command input from the input device 400 to the trajectory calculation unit 303, and the trajectory calculation unit 303 teaches the parameters of the current position and orientation that received the storage command. The parameter is stored in the parameter storage unit 302 as a point W ′.

  By this step S3, fine adjustment work is performed by the input device 400 so that the final arrival position E exists on the straight line in the insertion direction 113 of the workpiece 104.

  Hereinafter, this fine adjustment operation will be described in detail. In the fine adjustment operation of the first embodiment, first, the robot arm 201 is operated by the input device 400 to align the entrance side surface of the workpiece insertion hole 111 with the tip surface of the workpiece 104. For this surface alignment, the user inserts a thickness gauge as an adjustment jig between the entrance side surface of the workpiece insertion hole 111 and the tip surface of the workpiece 104 to adjust the inclination.

  Next, after adjusting the inclination, the center positions of the workpiece insertion hole 111 and the workpiece 104 are aligned. For this center alignment, a thickness gauge is applied to the side surface of the workpiece 104, the thickness gauge is inserted into the workpiece insertion hole 111, and the thickness is adjusted to a position where the thickness gauge can be inserted on all side surfaces.

  As described above, in step S3, the position and orientation of the workpiece 104 with respect to the workpiece insertion hole 111 of the workpiece fixing base 107 are determined using a thickness gauge as an adjustment jig.

  Since the fine adjustment work in this operation can be performed in a narrower range than the posture in the measurement using the conventional sensor and jig, it can be performed even if there are obstacles around.

  FIG. 4C shows a state after fine adjustment by the input device 400 so that the posture of the robot 200 is finely adjusted so that the final arrival position E exists on the straight line in the insertion direction 113 of the workpiece 104. Yes.

The teaching point W ′ indicating the position and orientation after fine adjustment is stored in the parameter storage unit 302 as the parameter P _{w ′} .

The matrix of parameter _{P w 'of} the teaching point W', joint value of each axis of the robot arm ^{_{201 [θ w'1, θ w'}} 2, θ w'3, θ w'4, θ w'5, θ w ^' ₆ ] and forward kinematics calculation using TCP, and the following relational expression holds.

  However, in this state, as shown in FIG. 4C, the final arrival position E does not exist on the straight line in the shift operation direction 112, and when the shift operation is performed, the workpiece 104 moves to the final arrival position E ′. Cannot be inserted into the workpiece insertion hole 111.

Therefore, the calibration calculating portion 305 of the control unit 300, using the teaching point W and teaching point W', performs calibration of the tool coordinate system Σ _tcp (S4, S5: Calibration step).

  Hereinafter, this calibration process will be described. First, the calibration calculation unit 305 performs TCP calibration using the teaching point W acquired in step S2 and the teaching point W ′ acquired in step S3 (S4: attention point calibration step), and creates a new TCP ′. To do.

  This step S4 will be described in detail. First, the calibration calculation unit 305 calculates a slope A caused by an assembly error using the teaching point W and the teaching point W ′.

Slope A (relative orientation of the teaching point W'for teaching point W) is represented by the rotation matrix R _A having 11.

Then, the calibration calculating unit 305 uses the rotation matrix _{R A} rotation matrix _{R W'and} number 11 number 10, and determines a rotation matrix _{R W_adj} excluding slope A from the teaching point W'.

The calibration calculation unit 305 obtains a _homogeneous transformation matrix _{w_adj} ⁰ T that represents the attitude of the teaching point W _adj reflecting the calibration value from the rotation matrix R _{w_adj of Expression} 12 and the position matrix q _{w ′ of Expression} 10.

Next, the calibration calculation unit 305 calculates the Euler angles [α _{w_adj} , β _{w_adj} , γ _{w_adj} ] from _{Equation 13} , _obtains the parameter P _{w_adj} of the teaching point W _adj , and stores it in the parameter storage unit 302.

That is, the calibration calculation unit 305 obtains the teaching point W _adj by calibrating the teaching point W ′ based on the relative posture (rotation matrix R _A ) of the teaching point W ′ with respect to the teaching point W. _{Xw_adj} , _{Yw_adj} , and _{Zw_adj} are _{XW ′} , _{YW ′} , and _{ZW ′} .

Then, the calibration calculating unit 305 is currently joint value of each axis of the robot arm 201 that has a position and orientation of the teaching point ^{_{W adj [θ w'1, θ}} w'2, θ w'3, θ w ^_'4, θ _w'5, determine the theta ^w' _6]. The calibration calculation unit 305 calculates the position and orientation of the origin of the flange coordinate system Σ _ef based on the base coordinate system Σ ₀ based on the calculation result. That is, the calibration calculation unit 305 calculates the position and orientation of the flange surface 210 with reference to the base coordinate system Σ ₀ by forward kinematics, and calculates the homogeneous transformation matrix _ef ⁰ T.

Next, the calibration calculation unit 305 calculates a homogeneous transformation matrix _{tcp ′} ^ef T in order to calculate a new TCP ′ using Equations 13 and 15.

The calibration calculation unit 305 calculates the position [X _{tcp ′} , Y _{tcp ′} , Z _{tcp ′} ] and Euler angles [α _{tcp ′} , β _{tcp ′} , γ _{tcp ′} ] from _{Equation 16} , and sets the parameter P of the new TCP ′. _The parameter storage unit 302 stores _{tcp ′} .

Thus, a new TCP ′ is created. That is, the calibration calculation unit 305, based on the position and orientation of the teaching point W _adj relative to the base coordinate system sigma _0, and the position and orientation of the origin of the flange coordinate system sigma _ef relative to the base coordinate system sigma ₀ Then, a calibrated TCP ′ is obtained with reference to the flange coordinate system Σ _ef .

Next, the trajectory calculation unit 303 defines a new tool coordinate system Σ _tcp ′ with the calibrated TCP ′ as the origin (S5).

FIG. 4D shows a state after the new teaching point W _adj and the new TCP ′ are created by the calibration operation, and step S5 will be described with reference to FIG. 4D.

In step S5, a new tool coordinate system Σ _tcp ′ with the new TCP ′ as the origin is defined. The vector direction of the tool coordinate system Σ _tcp ′ can be expressed by R _{w_adj} of the _homogeneous transformation matrix _{w_adj} ^ef T of _Expression 16 with respect to the base coordinate system Σ ₀ . The Z direction of the tool coordinate system Σ _tcp ′ is parallel to the insertion direction 113 of the workpiece 104 and can be inserted by performing a shift operation. When creating a shift motion trajectory in the Z direction of the tool coordinate system Σ _tcp ′, the position of the final arrival position E ″ is calculated when an arbitrary shift motion amount is given. In this case, when the distance from the teaching point W _adj to the final arrival position E'' is L, the teaching point after the shift operation, the following parameters P _e moved position and orientation from the teaching point W _adj.

Therefore, the teaching point W _e ″ at the target final arrival position E ″ is calculated by the following _homogeneous transformation matrix _{e ″} ⁰ T.

Since the teaching points W _adj and the teaching point W _e ″ are obtained from the equations 13 and 19, the operation can be designated by “Point to Point”. The trajectory calculation unit 303 calculates a trajectory for moving the tip (TCP) of the robot 200 along a straight line.

  Finally, the control command unit 304 controls the operation of the robot arm 201 based on the calculated trajectory, whereby the TCP moves linearly and the workpiece 104 can be inserted into the workpiece insertion hole 111.

By performing the shift operation using the defined tool coordinate system Σ _tcp ′ through the above steps, it is possible to linearly move from the position and orientation of the teaching point _Wadj to the final arrival position E.

  As described above, according to the first embodiment, the tool coordinate system can be calibrated without the robot arm interfering with surrounding obstacles even when the position and posture where the robot 200 can operate are limited.

  Further, since no sensor is required for calibration of the tool coordinate system, the cost can be reduced, and since measurement by the sensor is not required, the start-up time (teaching time) can be shortened.

[Second Embodiment]
Next, a robot calibration method for calibrating a tool coordinate system using the robot apparatus according to the second embodiment of the present invention will be described. FIG. 5 is a side view showing the state of the robot in each step of the robot calibration method according to the second embodiment of the present invention. FIG. 6 is a flowchart showing a robot calibration method according to the second embodiment of the present invention. FIG. 7 is a side view showing the state of the robot in each step of the robot calibration method according to the second embodiment of the present invention. The configuration of the robot apparatus according to the second embodiment is the same as that of the robot apparatus according to the first embodiment.

  In the second embodiment, the assembly error factor affecting the calibration is different from that in the first embodiment. That is, in the second embodiment, in addition to the inclination A generated in the robot hand 202 with respect to the flange surface 210 described in the first embodiment, an assembly error generated between the upper surface 101A of the gantry 101 and the work fixing base 107. There is a slope B due to. That is, in order to insert the workpiece 104 into the workpiece insertion hole 111, it is necessary to perform a shift operation of moving the workpiece 104 in a direction inclined by the inclination B with respect to the gantry 101.

  Also in the second embodiment, a case will be described in which an insertion operation of inserting the workpiece 104 gripped by the robot hand 202 into the workpiece insertion hole 111 of the workpiece fixing base 107 is described. Then, after the control device 300 (see FIGS. 1 and 2) moves the TCP to the teaching point where the insertion work starts, the robot arm 201 is operated so that the TCP shifts from the teaching point in the shift operation direction 112. The case where it is made to explain is demonstrated.

  FIG. 5A shows the position and posture of the robot arm 201 when the robot arm 201 is operated based on the teaching point W. FIG. FIG. 5B shows the position and posture of the robot arm 201 when the robot arm 201 is operated based on the adjusted teaching point W ′.

  In the second embodiment, steps S21, S22, and S23 shown in FIG. 6 are the same as steps S1, S2, and S3 shown in FIG. 3 described in the first embodiment, respectively.

  That is, in step S <b> 21, the calibration calculation unit 305 of the control device 300 inputs (acquires) a TCP design value from the parameter storage unit 302.

In step S22, the calibration calculating portion 305 of the controller 300, inputs a designed set teaching point based on the data (design taught point) W of the robot arm 201 relative to the base coordinate system sigma ₀ from the parameter storage unit 302 ( Acquisition) (design teaching point acquisition step). When the robot arm 201 is operated based on the teaching point W, the position and posture shown in FIG.

In step S <b> 23, the user operates the input device 400 to adjust the position and posture of the robot arm 201 based on the teaching point W, and the position and posture of the workpiece 104 held by the robot hand 202 with respect to the workpiece insertion hole 111. Decide. The trajectory calculation unit 303 of the control device 300 obtains a teaching point (adjustment teaching point) W ′ based on the base coordinate system Σ ₀ at this time (adjustment teaching point acquisition step). When the robot arm 201 is operated based on the teaching point W ′, the position and posture shown in FIG. The parameter of the teaching point W ′ is stored in the parameter storage unit 302 of the control device 300.

Here, the inclination generated between the insertion direction 113 of the workpiece 104 and the tool coordinate system Σ _tcp with the TCP as the origin in the position and posture of the robot arm 201 serving as the teaching point W ′ is synthesized by the inclination A and the inclination B. It becomes a slope.

  Therefore, since it is necessary to perform calibration calculation in consideration of the inclination A and the inclination B, the following steps are executed.

The input device 400 outputs a parameter of a teaching point (reference teaching point) N designated by a user operation. The teaching point (reference teaching point) N is such that the workpiece 104 held by the robot hand 202 with respect to the base coordinate system Σ ₀ contacts the upper surface (fixed surface) 101A of the gantry 101 as a reference surface. The teaching points are set based on the design data. More specifically, the teaching point N is a teaching point at a position and posture where the tip surface of the work 104 comes into surface contact with the upper surface 101A of the gantry 101. Note that the teaching point N is on a straight line between the contact surfaces of the robot arm 201 and the gantry 101.

  The teaching point N is a teaching point obtained by offline teaching using a simulator such as a computer. The external input / output unit 301 of the control device 300 inputs (acquires) the parameter of the teaching point N from the input device 400. The parameter of the teaching point N input by the external input / output unit 301 is stored in the parameter storage unit 302. The calibration calculation unit 305 reads out and inputs (acquires) the parameter of the teaching point N stored in the parameter storage unit 302 from the parameter storage unit 302 (S24: reference teaching point acquisition step).

Teaching point N is set by the parameter P _N representing the position and orientation as the reference base coordinate system sigma _0.

Using the TCP set in step S21 and the teaching point N set in step S24, the joint values [θ ⁿ ₁ , θ ⁿ ₂ , θ ⁿ ₃ , θ of the axes of the robot arm 201 whose TCP matches the teaching point N ⁿ ₄ , θ ⁿ ₅ , θ ⁿ ₆ ] are calculated by inverse kinematics. Thereby, the posture can be determined.

At this time, since the teaching point N and TCP coincide with each other, the following is obtained from the product of the homogeneous transformation matrix _{n + 1} ⁿ T of each axis of the robot 200 (1 axis to 6 axes are expressed as n = 1 to 6). The relationship of homogeneous transformation matrix holds.

  FIG. 7A shows the position and posture of the robot arm 201 at the teaching point N in an ideal state with no assembly error. Since the teaching point N is a design value, it is a target position and posture of the tip (TCP) of the robot 200 that does not consider the inclination A caused by an assembly error or the like. Therefore, in practice, in order to bring the tip surface of the workpiece 104 into parallel contact with the upper surface 101A of the gantry 101, it is necessary to finely adjust the inclination A caused by an assembly error or the like.

  In the second embodiment, first, the user operates the input device 400 to send a command to the control device 300 to operate the robot arm 201 based on the teaching point N. Thereby, the control command unit 304 of the control device 300 operates the robot arm 201 based on the parameter of the teaching point N. Next, the user operates the input device 400 to send an operation command (an angle command for each joint or a command for the position and orientation of TCP) to the control device 300. The control command unit 304 of the control device 300 that has received the operation command operates the robot arm 201 in accordance with the operation command.

  That is, online teaching is performed in which the robot arm 201 is operated by the user operating the input device 400, and the position and posture of the TCP in the real space are finely adjusted by the user's visual observation. Prior to the adjustment, the position and posture of the robot arm 201 may be adjusted while directly observing by the user without performing an operation based on the teaching point N on the robot arm 201.

  As described above, by performing online teaching for adjusting the position and orientation of the robot arm 201 based on the teaching point N, the trajectory calculation unit 303 determines the teaching point (adjustment reference teaching point) N from the adjusted position and orientation of the robot arm 201. 'Is created (S25: adjustment reference teaching point acquisition step).

  In this step S25, as shown in FIG. 7B, the robot arm 201 is positioned and positioned so that the tip surface of the workpiece 104 held by the robot hand 202 is in contact with the upper surface 101A of the gantry 101. Find the point N ′. That is, the user operates the robot arm 201 with the input device 400, and the control device 300 finely adjusts the position and orientation of the robot arm 201 to create a finely adjusted teaching point N ′.

  Specifically, the external input / output unit 301 outputs a storage command input from the input device 400 to the trajectory calculation unit 303, and the trajectory calculation unit 303 teaches the parameters of the current position and orientation that received the storage command. The parameter is stored in the parameter storage unit 302 as a point N ′.

Teaching point referenced to the base coordinate system sigma ₀ N'is represented by parameters P _N'indicating the position and orientation.

  In the adjustment operation in step S25, the inclination between the upper surface 101A of the gantry 101 and the front end surface of the workpiece 104 is adjusted using a thickness gauge as an adjustment jig, similarly to the adjustment operation of the teaching point W ′.

The matrix of teaching points ^N ′ includes joint values [θ ^{n ′} ₁ , θ ^{n ′} ₂ , θ ^{n ′} ₃ , θ ^{n ′} ₄ , θ ^{n ′} ₅ , θ ^{n ′} ₆ ] of each axis of the robot arm 201 and TCP. Can be calculated by forward kinematics calculation, and the following relational expression holds.

The above operation is performed only once when the robot arm 201 to which the robot hand 202 is assembled is placed on the gantry 101, and can be used to calibrate all tool coordinate systems Σ _tcp in a posture that requires a shift operation. .

Then, the calibration calculating portion 305 of the controller 300, step S23, S24, S25 teaching point created in W', the teaching point N, with the teaching point N', performs calibration of the tool coordinate system sigma _tcp (S26 , S27: Calibration step).

  Hereinafter, this calibration process will be described. First, the calibration calculation unit 305 performs TCP calibration using the teaching point W ′, the teaching point N, and the teaching point N ′ (S26: attention point calibration step), and creates a new TCP ′.

The step S26 will be described in detail. First, the calibration calculation unit 305 calculates the inclination A generated by the assembly error on the robot 200 side using the teaching point N and the teaching point N ′. To calculate the inclination A, calculates the difference between the teaching points N and teaching point N', the following homogeneous transformation matrix _N'N ^T.

The inclination A (relative attitude of the teaching point N ′ with respect to the teaching point N) is represented by a rotation matrix _RA of Expression 24.

Next, the calibration calculation unit 305 uses the rotation matrix R _{W ′ of Equation} 10 obtained in Step S23 and the rotation matrix R _A of _Equation 24 to obtain a rotation matrix R _{w_adj} obtained by removing the inclination A from the teaching point W ′. Ask.

The calibration calculation unit 305 obtains a _homogeneous transformation matrix _{w_adj} ⁰ T that represents the attitude of the teaching point W _adj reflecting the calibration value from the rotation matrix R _{w_adj of Expression} 25 and the position matrix q _{w ′ of Expression} 10.

The calibration calculation unit 305 calculates Euler angles [α _{w_adj} , β _{w_adj} , γ _{w_adj} ] from _{Equation 26} , _obtains the parameter P _{w_adj} of the teaching point W _adj , and stores it in the parameter storage unit 302.

That is, the calibration calculation unit 305 obtains the teaching point W _adj by calibrating the teaching point W ′ based on the relative posture (rotation matrix R _A ) of the teaching point N ′ with respect to the teaching point N. _{Xw_adj} , _{Yw_adj} , and _{Zw_adj} are _{XW ′} , _{YW ′} , and _{ZW ′} .

Then, the calibration calculating unit 305 is currently joint value of each axis of the robot arm 201 that has a position and orientation of the teaching point ^{_{W adj [θ w'1, θ}} w'2, θ w'3, θ w ^_'4, θ _w'5, determine the theta ^w' _6]. The calibration calculation unit 305 calculates the position and orientation of the origin of the flange coordinate system Σ _ef based on the base coordinate system Σ ₀ based on the calculation result. That is, the calibration calculation unit 305 calculates the position and orientation of the flange surface 210 with reference to the base coordinate system Σ ₀ by forward kinematics, and calculates the homogeneous transformation matrix _ef ⁰ T.

Next, the calibration calculation unit 305 calculates a homogeneous transformation matrix _{tcp ′} ^ef T from _Equations 26 and 28 in order to calculate a new TCP ′ based on the flange surface 210 in the current posture.

The calibration calculation unit 305 calculates the position [X _{tcp ′} , Y _{tcp ′} , Z _{tcp ′} ] and Euler angles [α _{tcp ′} , β _{tcp ′} , γ _{tcp ′} ] from _{Equation 29} , and sets the parameter P of the new TCP ′. _{tcp ′} is stored in the parameter storage unit 302.

  As described above, the TCP is calibrated to create a new TCP ′.

That is, the calibration calculation unit 305, based on the position and orientation of the teaching point W _adj relative to the base coordinate system sigma _0, and the position and orientation of the origin of the flange coordinate system sigma _ef relative to the base coordinate system sigma ₀ Then, a calibrated TCP ′ is obtained with reference to the flange coordinate system Σ _ef .

Next, the trajectory calculation unit 303 defines a new tool coordinate system Σ _tcp ′ with the calibrated TCP ′ as the origin (S27). This step S27 is the same as step S5 of the first embodiment.

_'By defining a new tool coordinate system sigma _tcp' new tool coordinate system sigma _tcp can perform shift operation by.

As described above, according to the second embodiment, the robot arm 201 does not interfere with surrounding obstacles even when there is an inclination B due to an assembly error occurring between the gantry 101 and the workpiece fixing base 107. The tool coordinate system Σ _tcp can be calibrated.

  In the second embodiment, the teaching point N is on a straight line between the robot arm 201 and the grounding surface of the gantry 101, but is not limited thereto. That is, the reference surface is the upper surface 101A of the gantry 101, but is not limited thereto. For example, any location where the position and orientation are guaranteed from the reference origin of the robot arm 201 is acceptable.

[Third Embodiment]
Next, a robot calibration method for calibrating a tool coordinate system using the robot apparatus according to the third embodiment of the present invention will be described. FIG. 8 is a perspective view showing an adjustment jig used in the robot calibration method using the robot apparatus according to the third embodiment of the present invention.

  In the first and second embodiments, the case where the thickness gauge is used as the adjustment jig has been described. However, in the third embodiment, the alignment jig 122 and the insertion jig 123 shown in FIG. The case where the adjustment jig 120 made of is used will be described.

  The gripping jig 121 is a cylindrical member, and has the same shape as the workpiece 104 or a shape that can be regarded as the workpiece 104. Note that the gripping jig 121 may be the actual workpiece 104 (see FIG. 1 or the like) inserted into the workpiece insertion hole 111.

  The gripping jig 121 and the insertion jig 123 are jigs having the same outer diameter, and the axis alignment jig 122 is an inner diameter hole having a certain error from the outer diameters of the gripping jig 121 and the insertion jig 123. A ring-shaped jig with The insertion jig 123 is inserted into the workpiece insertion hole 111, and the axis alignment jig 122 is fitted into the insertion jig 123. Thereby, the adjustment jig 120 is mounted in the workpiece insertion hole 111. When the center axis of the holding jig 121 is displaced or inclined with respect to the adjustment jig 120, the axis alignment jig 122 cannot move between the holding jig 121 and the insertion jig 123. ing.

  In steps S3 and S23, the teaching point W is finely adjusted by operating the input device 400 using these jigs 121, 122, and 123.

  In this fine adjustment operation, first, the robot hand 202 grips the grip jig 121. Next, an insertion jig 123 that has the same shape as the workpiece insertion hole 111 and can be positioned is inserted into the workpiece insertion hole 111. At this time, the axis alignment jig 122 is fitted into the insertion jig 123.

  Next, the robot arm 201 is operated by the operation of the input device 400, and the tip surface 121A of the gripping jig 121 is brought into surface contact with the surface 123A that is the first contact surface of the insertion jig 123. By this operation, the inclination between the robot arm 201 and the workpiece insertion hole 111 is adjusted.

  Next, the robot arm 201 is moved in the direction along the mated surfaces 121A and 123A so that the axis alignment jig 122 can slide to the gripping jig 121 side, and the axis alignment is adjusted. By adjusting the axis aligning jig 122 to the gripping jig 121 side, the outer peripheral surface 121B of the gripping jig 121 comes into surface contact with the inner peripheral surface 122A that is the second contact surface of the axis aligning jig 122. The work is complete. That is, the position where the axis alignment jig 122 smoothly moves to the insertion jig 123 is the position and posture where the inclination and the central axis coincide.

  In this way, the adjustment jig 120 is used to bring the front end surface 121A of the gripping jig 121 into surface contact with the surface 123A of the insertion jig 123, and the outer peripheral surface 121B of the gripping jig 121 is brought into contact with the axis alignment jig 122. Are brought into surface contact with the inner peripheral surface 122A. Thereby, the inclination of the holding jig 121 is adjusted by the insertion jig 123, and the central axis of the holding jig 121 is adjusted by the axis alignment jig 122. Therefore, the position and orientation of the gripping jig 121 with respect to the workpiece insertion hole 111 are determined with high accuracy.

  Note that the axis alignment jig 122 may be fitted first to the gripping jig 121 side instead of the insertion jig 123 side. Then, after aligning the surface 123A of the insertion jig 123 with the tip surface 121A of the gripping jig 121, the central axis is adjusted, and the place where the axis alignment jig 122 moves smoothly to the insertion jig 123 side is determined. The position and posture where the inclination and the central axis coincide with each other may be used.

  Using the fine adjustment method as described above, it is possible to create a teaching point with higher accuracy than the thickness gauge by creating the teaching point W ′ after fine adjustment of the position and orientation where the inclination and the central axis match. it can.

  The present invention is not limited to the embodiment described above, and many modifications are possible within the technical idea of the present invention.

  In the first to third embodiments, the case where the robot hand 202 has three fingers having joints has been described. However, the number is not limited to three, and it is only necessary to have two or more fingers. The robot hand 202 may be configured to be able to grip the workpiece, and is not limited to the finger, and may have a gripping claw for fixing the workpiece with a latch or the like.

  Moreover, although the 1st-3rd embodiment demonstrated the case where the input device 400 was a handy terminal or a teaching pendant, it is not limited to this. It suffices if parameters can be edited and newly created. For example, a computer may be connected to the control device 300, and the robot 200 may be operated and parameters may be edited or newly created using simulator software or teaching software in the computer. In addition, parameters may be edited or newly created by directly inputting a text file created by a computer to the control device 300.

DESCRIPTION OF SYMBOLS 100 ... Robot apparatus, 104 ... Work, 107 ... Work fixing base, 111 ... Work insertion hole, 200 ... Robot, 201 ... Robot arm, 202 ... Robot hand (tool), 210 ... Flange surface (tip of robot arm), 300 ... Control device 303 ... Trajectory calculation unit, 305 ... Calibration calculation unit, Σ ₀ ... Base coordinate system (reference coordinate system), Σ _ef ... Flange coordinate system (tip coordinate system), Σ _tcp ... Tool coordinate system (attention point coordinates) system)

Claims (10)

A reference coordinate system, a tip coordinate system with the tip of the robot arm as the origin, and a point of interest coordinate system with the point of interest set based on the tip coordinate system as the origin are defined,
A design teaching point acquisition step for acquiring a design teaching point including distance information and angle information set based on the design data of the robot arm with reference to the reference coordinate system;
An adjustment teaching point acquisition step of adjusting the position and orientation of the robot arm based on the design teaching point to obtain an adjustment teaching point including distance information and angle information based on the reference coordinate system;
Based on the relative orientation of the adjustment teaching point with respect to the design teaching point, a predetermined direction based on the target point coordinate system after adjusting the position and orientation of the robot arm is the same as before the adjustment in the reference coordinate system. A calibration step of calibrating the adjustment teaching points and calibrating the point-of-interest coordinate system to match,
After the robot arm is operated so that the attention point moves to the adjustment teaching point after being calibrated in the calibration step, the predetermined point based on the attention point coordinate system after being calibrated in the calibration step And a step of controlling an operation of the robot arm so as to shift in a direction from the adjustment teaching point after being calibrated in the calibration step. A robot hand is attached to the tip of the robot arm,
The predetermined direction is a direction in which the point of interest is linearly moved when a workpiece gripped by the robot hand is inserted into a workpiece insertion hole,
In the adjustment teaching point acquisition step, the adjustment teaching point is obtained by causing the robot hand to grip a gripping jig and determining the position and orientation of the gripping jig with respect to the workpiece insertion hole. The robot control method according to claim 1. The robot control method according to claim 2 , wherein in the adjustment teaching point acquisition step, the position and orientation of the gripping jig with respect to the workpiece insertion hole are determined using an adjustment jig.   The robot control method according to claim 3, wherein the adjustment jig is a thickness gauge.   The adjustment jig has a first contact surface that contacts the front end surface of the gripping jig and a second contact surface that contacts the outer peripheral surface of the gripping jig, and is attached to the workpiece insertion hole. The robot control method according to claim 3, wherein the robot control method is configured as follows.   The robot control method according to claim 2, wherein the gripping jig is a workpiece inserted into the workpiece insertion hole.   The robot control method according to claim 1, wherein the design teaching point is obtained by a simulator.   A method for manufacturing an article, comprising assembling the article by controlling the operation of the robot arm by the robot control method according to claim 1. A reference coordinate system, a tip coordinate system with the tip of the robot arm as the origin, and a point of interest coordinate system with the point of interest set based on the tip coordinate system as the origin are defined,
Design teaching point acquisition means for acquiring a design teaching point including distance information and angle information set based on the design data of the robot arm based on the reference coordinate system;
Adjustment teaching point acquisition means for adjusting the position and orientation of the robot arm based on the design teaching point to obtain an adjustment teaching point including distance information and angle information based on the reference coordinate system;
Based on the relative orientation of the adjustment teaching point with respect to the design teaching point, a predetermined direction based on the target point coordinate system after adjusting the position and orientation of the robot arm is the same as before the adjustment in the reference coordinate system. Calibration means for calibrating the adjustment teaching point and calibrating the point-of-interest coordinate system so as to match,
After the robot arm is operated so that the attention point moves to the adjustment teaching point after being calibrated by the calibration means, the predetermined point with reference to the attention point coordinate system after being calibrated by the calibration means And a controller for controlling the operation of the robot arm so as to shift in a direction from the adjustment teaching point after being calibrated by the calibration means. A robot hand is attached to the tip of the robot arm,
The predetermined direction is a direction in which the point of interest is linearly moved when a workpiece gripped by the robot hand is inserted into a workpiece insertion hole,
The adjustment teaching point acquisition means obtains the adjustment teaching point by causing the robot hand to grip a gripping jig and determining the position and posture of the gripping jig with respect to the workpiece insertion hole. The control device according to claim 9.

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