JPH05111886A - Indication of calibration point of robot manipulator and calibration work - Google Patents

Abstract

PURPOSE:To reduce calibration work by installing a rod which can be inserted into a circular hole of a jig as a tool into a wrist axis of a robot manipulator, by inserting the rod into the hole to carry out fixed-point observation with the front end of the tool as a control point of the manipulator, and by utilizing the position of the control point and position information. CONSTITUTION:A six-axis power sensor is provided on a wrist axis of a robot manipulator, and by using a system for carrying out impedance control by a controller, a jig 2 having a circular hole 2a is prepared at a fixed point, and a rod 3 that can be fitted into the hole 2a as a tool of a robot 1 is installed in the wrist axis of the manipulator. After the rod 3 is inserted into the hole 2a, fixed-point observation is carried out, while indication of calibration point and calibration work can be carried out. Information on the location and the position is accurately obtained by inserting the rod only once. Teaching work for calibration is thus halved, and the insertion of the rod can be performed unmanned by an impedance control mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a calibration point teaching method and a calibration work method for a robot manipulator when an automatic production line using a robot or a robot is required to perform an operation by offline teaching.

[0002]

2. Description of the Related Art A robot manipulator calibration operation, that is, a control point of a robot is moved to a fixed point prepared for calibration, the theoretical angle of each axis of the robot at the fixed point, and the measured actual In the work of adjusting the displacement between the angles of the axes of the robot, the method of teaching the robot is generally used to move the control point of the robot manipulator to a fixed point (Japanese Patent Laid-Open No. 62-156701). See the bulletin).
Usually, the information obtained by this method is position information, and posture information is not used. On the other hand, JP-A-63-2
Japanese Patent No. 51810 discloses a block attached to the Z-axis at the tip of a horizontal joint robot, a pin that is freely supported only in the up-down direction of the block, and a measuring unit that measures the relative distance between the robot tip and the pin. , Including an elastic body that produces a reaction force in relation to the relative distance between the robot tip and the pin, and a hole in which the robot is mounted and into which the pin is inserted, including a plurality of openings having different heights A calibration device for a horizontal articulated robot is described, which includes a certain measurement table and an analysis device that reads information such as the current posture of the robot, reads the value of the measurement means, and performs arithmetic processing. Further, in Japanese Unexamined Patent Publication No. 2-160492, an arm portion that is driven to an arbitrary position, a finger portion that is connected to the tip of the arm portion and that holds a workpiece, and the arm portion and the finger portion are described. A force sensor that is interposed between the force sensor and the force sensor that detects the force acting on the finger portion, and a determination unit that determines the mounting state of the work and the shift state of the teaching point of the mounting operation based on the detection output from the force sensor. An industrial robot with and is described.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention JP-A-62-15
In the normal calibration work as described in Japanese Patent No. 6701, since the posture is not managed, only position information can be obtained from the position teaching. The problem is that you can get two data in one operation and use only one. Further, the above-mentioned Japanese Patent Laid-Open No. 63-251810
The device described in the publication does not have a force sensor, and therefore cannot be deployed in multiple joints. The above-mentioned Japanese Patent Laid-Open No. 2
In the industrial robot described in Japanese Patent Laid-Open No. 160492, a method is shown in which the teaching data is finely corrected when the assembly work is performed by the force sensor. However, this force sensor merely serves as an auxiliary means of a tool having the sensor. It is only used, and it is not intended to calibrate the robot or record fine correction data and positively use it to correct the robot. Therefore, the problem to be solved by the present invention is to reduce the teaching work for calibration of the robot by taking in the position information and the posture information by one-time teaching to the robot.

[0004]

In order to solve this problem, the calibration point teaching method according to the present invention provides a robot manipulator with a 6-axis force sensor on the wrist axis, and a robot controller controls the impedance of the robot manipulator. When teaching calibration points using the robot system, prepare a jig with a circular hole at a fixed point, and use a rod that can be inserted into the circular hole of the jig as a tool on the wrist axis of the robot manipulator. Mounted, the tip of this tool is used as the control point of the robot manipulator, and a rod that is the tool of the robot is inserted into the circular hole of the jig for fixed point observation, and the position information and attitude of the control point of the robot Use the information as calibration information. Further, the calibration work method according to the present invention is such that a 6-axis force sensor is provided on the wrist axis of the robot manipulator, and when the calibration work is performed by using the robot system in which the robot controller performs impedance control of the robot manipulator, Prepare a jig with holes at fixed points,
A rod that can be just inserted into the circular hole of the jig is attached to the wrist shaft of the robot manipulator as a tool, and the tip of this tool is used as the control point of the robot manipulator.
A rod, which is a tool of the robot, is inserted into the circular hole of the jig to perform fixed point observation, and calibration work is performed.

[0005]

In the present invention, a jig 2 having a circular hole 2a is provided by using a robot system in which a 6-axis force sensor is provided on the wrist axis of a robot manipulator and the robot controller controls the impedance of the robot manipulator.
(Fig. 3) is prepared as a fixed point, and a rod 3 (Fig. 4) that can be just inserted into the circular hole of this jig is prepared as a robot tool, and this tool 3 is attached to the wrist shaft of the robot manipulator (Fig. 1) In the system in which the tip of the tool 3 is the control point of the robot manipulator, the jig 2
By inserting the rod 3 which is a tool of the robot into the circular hole 2a of FIG. 2 (FIG. 2), fixed point observation is performed, and calibration point teaching and calibration work are performed. By this method, it is possible to accurately obtain position information and posture information. According to this calibration point teaching method, the position information and the posture information can be obtained by inserting the rod once, and the teaching work for the calibration of the robot can be halved. In addition, the impedance control mechanism allows the rod insertion work to be unmanned and has an automatic calibration data collection function.

[0006]

EXAMPLES The present invention will be specifically described below with reference to examples. FIG. 1 is an explanatory view showing a state in which a calibration work according to the present invention is being performed, where 1 is a robot, 2 is a jig, and 3 is a tool. In the present invention, a jig 2 in which a circular hole 2a is processed is prepared as shown in FIG. 3, and a rod 3 which can be just inserted into the circular hole 2a of the jig 2 is prepared as shown in FIG. To do. Then, using the impedance control of the robot system, the robot is made to perform the insertion work based on the teaching data previously taught. Robot 1 by impedance control
Even if the positioning accuracy of the is slightly incorrect, the insertion work can be performed smoothly and completely. The robot 1 is also programmed to continue this insertion operation until it hits the bottom of the hole 2a by impedance control.
When it hits the bottom of a, it stops moving (see Fig. 2). Then, the angle of each axis at this time is measured, and the parameters that affect the accuracy of the robot are adjusted based on the position information and the posture information. Since the calibration of the robot is taught by teaching a plurality of points and statistically processed, the present invention can halve only 12 points, which has been conventionally required to teach 24 points. Specifically, by teaching,
P (x, y, z) as position coordinates and θ as attitude data
Data of (α, β, γ) can be obtained. In the case of a 6-axis robot, each axis has four error factors, and the robot calibration is to obtain four unknowns of each axis.
It is necessary to find the solution of simultaneous equations with 6 axes x 4 and a total of 24 variables. To find a solution of 24 variables, at least 24
It is necessary to formulate individual equations. One position data or one attitude data is required to set up one equation. Originally, robot calibration cannot be performed unless 24 points of teaching data are created, but since the posture is fixed by the hole inserting work in the present invention, the same effect can be obtained from 12 points of teaching. Obtainable.

[0007]

As described above, according to the robot calibration point teaching method of the present invention, since the position information and the posture information can be obtained by inserting the rod once, the calibration work can be halved. In addition, the impedance control mechanism allows unmanned rod insertion work, that is, it has an automatic calibration data collection function.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a state in which a calibration work according to the present invention is being performed.

FIG. 2 is a sectional view showing a state in which a rod is inserted into a hole of a jig.

FIG. 3 is a perspective view showing an example of a jig.

FIG. 4 is a perspective view showing a bar paired with a jig.

[Explanation of symbols]

 1 robot, 2 jig, 2a hole, 3 bar (tool)

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location G05B 19/42 R 9064-3H

Claims (2)

[Claims] 1. When performing calibration point teaching using a robot system in which a 6-axis force sensor is provided on a wrist axis of a robot manipulator and a robot controller controls impedance of the robot manipulator,
Prepare a jig with a circular hole at a fixed point, attach a rod that can be just inserted into the circular hole of the jig as a tool to the wrist axis of the robot manipulator, and use the tip of this tool as the control point of the robot manipulator. A robot characterized by performing fixed point observation by inserting a rod, which is a tool of the robot, into a circular hole of the jig, and using position information and posture information of the control point of the robot as calibration information. Manipulator calibration point teaching method. 2. A jig having a circular hole is used when performing calibration work using a robot system in which a robot manipulator has a 6-axis force sensor on a wrist shaft and a robot controller controls impedance of the robot manipulator. Prepare a fixed point, attach a rod that can be inserted into the circular hole of the jig as a tool to the wrist shaft of the robot manipulator, and use the tip of this tool as the control point of the robot manipulator to make the circular hole of the jig. A calibration work method for a robot manipulator, which comprises performing a calibration work by observing a fixed point by inserting a rod, which is a tool of the robot, into the.