JPH06161538A - Direct teaching method for robot - Google Patents

Abstract

PURPOSE:To exactly and conveniently position a terminal effector to be the tool of a robot. CONSTITUTION:A robot is provided with a function discriminating the geometrical shapes such as the points, lines, surfaces, etc., of the shape of a working object 5, measuring the position coordinates of the feature points, measuring the relative positioning relation between a terminal effector 3 and the working object 5 and moving the terminal effector 3 so that this relative positioning relation may satisfy a prescribed condition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for directly teaching a robot.

[0002]

2. Description of the Related Art In the work using a robot, it is necessary to accurately provide the robot with position information necessary for the work. Since a robot usually has high positioning repeatability,
A direct teaching method is often used in which the hand effector of the robot is directly positioned on an object and the working position is stored. In such a method, it is necessary to accurately and simply position the hand effector (tool) of the robot at the work position of the work target. Therefore, conventionally, the X, Y, and Z of the hand effector are used for this positioning. A method of performing translation in the axial direction and rotational movement around each axis by operating a teaching box is mainly used.

FIG. 3 is a block diagram of a device to which a conventional robot direct teaching method is applied. 1 is a robot arm, 2 is a controller for controlling the operation of the robot arm 1,
3 is a hand effector such as a tool for performing work, 4 is a hand effector 3
Is a teaching box that sends a command to move the robot arm 1 in the X, Y, and Z axis directions and to change the posture around each axis. Further, 41 to 46 are switches in the teaching box 4, which are X,
Commands for translational movements in the Y and Z axis directions and rotational movements about the respective axes are assigned. Further, 5 is a work object, and 6 is one of the ridgelines of the work object 5, and required work is performed on the work object 5 while moving the tip of the hand effector 3 on this ridgeline. It is a thing. Also, 10
Numerals to 15 are points on the ridgeline 6 of the work target, and the robot can perform the position of these points and the posture of the hand effector at each point while moving the hand effector 3 along the ridgeline 6. .

In such a direct teaching method, when the hand effector 3 is positioned at a point 10 for teaching the ridge line 6, for example, the axial switches of the switches 41 to 43 are individually operated to accurately operate the hand effector 3. Further, the robot is taught by operating the axial switches 44 to 46 so that the robot is positioned at the point 10 and has an appropriate posture for work, and repeating the switch operation for these positions and postures. In this case, all the axial switches are operated so that the position and posture of the hand effector 3 become appropriate for the work.

[0005]

However, when the hand effector is positioned at the target position of the work object in an appropriate posture, the axis to be operated in order to move the hand effector by the proper amount in the work position direction. It is necessary to appropriately select the switch, and since this operation is complicated and trial and error are repeated until the final target position is reached, there is a drawback that work efficiency is poor when teaching the robot.

In order to improve the operability, a force sensor is attached to the hand effector of the robot, a force applied to the hand effector is detected, and the control function is to move or change the posture of the robot in the direction of the force. It is proposed to have. That is, in this case, the teacher grasps the hand effector with his / her hand, and applies force so that the hand effector takes a position and posture suitable for the work, and moves the hand effector to the work position accurately and easily.

However, in the case of such a method, it is necessary to move the robot in a sufficiently fast and stable manner in response to the force applied to the hand effector, but since the force is manually applied to the hand effector, it is sufficient. There was a problem that it was difficult to secure high responsiveness and stability. Further, since it is necessary to position the hand effector so as to satisfy all the conditions necessary for the work with respect to all the X-axis, Y-axis, and Z-axis positions and the rotation angles around the respective axes, the teacher's hand-effector should be positioned. Although the operational burden is somewhat reduced, it is still large.

Therefore, an object of the present invention is to provide an accurate and simple positioning method for a hand effector.

[0009]

In order to solve such a problem, the present invention measures the shape of a work object and uses the measured shape data of the work object to calculate points, lines and surfaces of work positions. While extracting any geometrical feature, the relative position of the work position on the work object with respect to the hand effector is measured using the geometric feature of the work position, and the distance and angle in the relative positional relationship are measured. In this method, either one of the position and the posture or both the position and the posture of the hand effector is moved so as to satisfy a predetermined condition. Also,
An automatic control operation that always satisfies a predetermined condition regarding the positional relationship between the work position and the hand effector, and an operation that moves both the position and the attitude of the hand effector or one of the position and the attitude by an external input. This is a method that is executed at the same time.

[0010]

The relative position of the work position on the work object with respect to the hand effector is measured by using the geometrical characteristics of the work position, and the distance and angle in the relative position relation satisfy predetermined conditions. The hand effector is moved to. Further, the automatic control operation for the positional relationship between the work position and the end effector and the operation for moving the end effector by an external input are simultaneously performed.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of an apparatus to which a direct teaching method for a robot according to the present invention is applied. In the figure, the same parts as those of the conventional device are designated by the same reference numerals and the description thereof is omitted.

In FIG. 1, 30 is a shape measuring device for measuring the shape of the work target 5, 31 is a geometric feature of the work position extracted from the shape data of the work target acquired by the shape measuring device 30. A position calculation device that measures the position coordinates of the work position from the characteristic points and calculates the relative position with respect to the hand effector 3. This position calculation device 31 has two
An algorithm for detecting the ridge line 6 formed by the intersection of two planes as a shape feature and a calculation formula for calculating the position of the ridge line are incorporated in advance, and two planes of the upper bottom surface of the work target 5 and one side surface are included. It is possible to detect the ridge line 6 formed by the intersection of the above and calculate the relative position between each point 10 to 15 on the ridge line 6 and the hand effector 3.

Reference numeral 32 is an output from the teaching box 4 and the position calculating device 31, and the hand effector is used so that the distance and angle in the relative positional relationship between the work position and the hand effector 3 satisfy predetermined conditions. 3 is a control information calculation device for calculating control information for moving the position and / or orientation of No. 3, or both, and the calculation result is sent to the control device 2. In the example of FIG. 1, as the condition that the positional relationship between the work position and the hand effector 3 should be satisfied, for example, a condition for matching the position of the hand effector 3 with the work position is given. Further, all of 33 to 35 are buttons which are attached to the teaching box 4 and operated by the teacher. Among them, the button 33 drives the above-mentioned devices 30 to 32 to detect the work position and move the position of the hand effector 3. Is to instruct the start of. Further, the button 34 is used for detecting the work position and the hand effector 3.
The button 35 instructs the controller 2 to store the position / orientation of the hand effector 3 at that time, as well as instructing to stop the movement.

Next, the operation of the apparatus configured as described above will be described. When teaching the work positions of points 10 to 15 to the robot, first, the button 33 is pressed to instruct the detection of the work position based on the geometrical feature of the ridge and the start of the operation of matching the hand effector 3 with the work position. . Then, the hand effector 3 is positioned near the point 10 using the teaching box 4. Then, the shape measuring device 30 first operates to measure the shape of the work target object, and then the position calculating device 31 extracts the ridge line portion as the geometrical feature of the shape of the ridge line 6 from the shape information, and calculates the work position. And the relative positional relationship between the hand effector 3 will be clarified.

Then, the control information calculation device 32 uses the output of the position calculation device 31 to calculate the control information of the robot operation for matching the tip position of the hand effector 3 with the working position, and the result is calculated by the control device 2. Send to. As a result, the tip of the hand effector 3 automatically coincides with the ridge line 6. However, the posture of the hand effector 3 is not controlled and is given by the operation of the teaching box 4 by the teacher. The position of the hand effector 3 is controlled by controlling the posture of the hand effector 3 by operating the teaching box 4 by the teacher.
When it is confirmed that the posture is appropriate for the work, the button 35 is pressed and the position / posture information of the hand effector 3 is stored in the control device 2.

In this way, since the hand effector 3 is automatically positioned at the position of the point 10, the instructor operates to align the ridge line 6 in the ridge direction and optimize the posture of the hand effector 3 at each position. It is sufficient that the tip end of the hand effector 3 is aligned with the ridge line 6 and is released. Then, such an operation is continued while moving the hand effector 3 along the ridge line 6, teaches the position / orientation of the points 11 to 15, and when the teaching is completed, the button 34 is automatically positioned when the button 34 is pressed. Cancel the operation.

In these operations, as the relative positional relationship between the work position and the hand effector 3, the position of the hand effector 3 does not coincide with the work position, but the posture of the hand effector 3 is relative to the work site. If the position calculation device 31 is provided with an algorithm that provides a certain direction, the posture control of the hand effector 3 can be automatically performed in the same manner. In this case, if a plurality of conditions are set as the relative positional relationship between the work position and the hand effector 3, and a plurality of buttons 33 are installed according to the number of conditions, each of the conditions can be appropriately selected during teaching. Can be used.

FIG. 2 is a block diagram showing another embodiment of the present invention, in which the position of the hand effector 3 coincides with the work position and the posture of the hand effector 3 faces a certain direction with respect to the work site. An example of a case where such conditions are given and both the position and the posture of the hand effector 3 are automatically controlled is shown. 7 here
Indicates the direction of the ridge line 6, and 8 indicates the plane including the tip of the hand effector 3 and perpendicular to the direction 7. The plane 8 is generated as a normal vector of the surface from the position calculation device 31 by giving the position calculation device 31 two points on the ridge line 6. In addition, 9 has shown the central axis of the hand effector 3.

In the example of FIG. 2, the condition of the position of the hand effector 3 coincides with the working position and the condition that the central axis 9 of the hand effector 3 is held in the plane 8 is given. A program for realizing the movement operation of the robot satisfying this condition is given to the position calculation device 31 in advance. In this case, the central axis 9 of the hand effector 3
Are always included in the surface 8, but the degree of freedom remains in the direction within the surface 8, and the direction can be changed by operating the teaching box 4 separately. Further, since the tip of the hand effector 3 is controlled so as to be always positioned on the ridge line 6, its direction is changed while the central axis 9 thereof is kept in the plane 8, or the parallel movement of the surface 8 causes the movement thereof. The tip can be moved along the ridge line 6.

Therefore, when the robot is manually operated by the teacher using the teaching box 4, the central axis 9 of the hand effector 3 is always held in the plane 8 and the tip thereof is always aligned with the ridge line 6. Therefore, it is sufficient for the instructor to perform the alignment of the hand effector 3 in the direction 7 of the ridge line 6 and the proper orientation of the hand effector 3 in the plane 8, and the operation load for determining the position and orientation is required. Significantly reduced.

That is, by simultaneously executing the automatic positioning function of the robot and the manual operation of the teacher, the teacher does not accurately position the hand effector 3 on the ridge line 6,
Even when the finger effector 3 is moved along the ridge line 6, the hand effector 3 accurately moves in the plane 8 perpendicular to the ridge line 6 and the tip of the hand effector 3 is always positioned on the ridge line 6 by the function of the present invention. Therefore, the route of the ridge line 6 is taught to the robot accurately and at high speed. As described above, by using the apparatus of the present embodiment, a part of the position and orientation control of the robot in teaching is automated, and the automatic control and the position and orientation determination by manual operation are combined to reduce the work load on the teacher. In addition, accurate positioning can be achieved.

[0022]

As described above, according to the present invention,
The relative position of the work position on the work object with respect to the hand effector is measured by using the geometric feature of the work position, and the hand effector is moved so that the relative positional relationship satisfies a predetermined condition. As a result, the work can be taught to the robot easily and accurately, and the burden on the teacher can be reduced. Further, since the automatic control operation for the positional relationship between the work position and the hand effector and the operation for moving the hand effector by external input are simultaneously executed, the robot can be taught the movement path accurately and at high speed.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of an apparatus to which a robot direct teaching method according to the present invention is applied.

FIG. 2 is a block diagram showing another embodiment of the present invention.

FIG. 3 is a block diagram of a conventional robot device.

[Explanation of symbols]

 1 Robot Arm 2 Control Device 3 Hand Effector 4 Teaching Box 5 Work Object 6 Ridge Line 8 Surface 10-15 Point on Ridge Line 30 Shape Measuring Device 31 Position Calculation Device 32 Control Information Calculation Device 33-35, 41-46 Button

Claims (2)

[Claims] 1. A teaching device of a robot, wherein a hand effector of a robot is directly positioned on a work object to store the work position in the robot, the shape of the work object is measured, and the measured work object is measured. The geometrical feature of the point, line or surface of the work position is extracted from the shape data, and the relative position of the work position on the work object to the hand effector is measured using the geometric feature of the work position. In addition, the robot is characterized in that either one of the position and the posture of the hand effector or both the position and the posture are moved so that the distance and the angle in the relative positional relationship satisfy a predetermined condition. Direct teaching method. 2. The direct teaching method for a robot according to claim 1, wherein an automatic control operation that always satisfies the predetermined condition regarding the positional relationship between the work position and the hand effector, and the position of the hand effector by external input. A direct teaching method for a robot, characterized in that both of the posture and the posture or the movement of moving either the position or the posture are executed at the same time.