JPH04304987A - Robot control device - Google Patents

Abstract

PURPOSE:To smoothly move the hand effector of a robot in a desired direction by providing the robot having plural moving axes with a filter means which uses software to smooth a command of direction or speed on a generated rectangular coordinate. CONSTITUTION:An originating means 202 for the vector of each direction originate predetermined unit vectors in accordance with a control variable input by a control variable input means 201. Outputs smoothed by filter operations as to each of the X, Y, Z directions of a rectangular coordinate are originated by a filter means 203 in accordance with the vectors originated. An amount of movement generating means 204 multiplies the originated amount of each direction by a fixed amount of speed. The amounts of movement in each direction after a very short time are added together by a rectangular coordinate position command generating means 205 to generate a position command after the short time. A coordinate converting means 206 converts the position command into the rotary angle command of a robot motor and a servo rotation transfer means 207 transfers the rotary angle command to each servo circuit.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a robot control device.

0002

[Prior Art] In order to remotely control a robot on orthogonal coordinates for teaching work, etc., a command for a fixed amount of movement is generated by performing acceleration/deceleration processing every time there is an operation in the direction of movement. There was a method that worked step by step. There is also a method of generating step-like commands like the one above before the operation, storing them alternately in two FIFO memories, and controlling the robot with the sum of these commands so that the robot can operate without stopping. Ta.

Another method has been to generate an acceleration/constant speed command in that direction while there is an operation in that direction, and then generate a deceleration command to stop the robot when there is no more operation.

0004

[Problem to be Solved by the Invention] The above method of moving step by step is good for accurately moving the necessary step size, but it is difficult to move the robot's hand effector to a distant work point quickly. was annoying. In addition, the method of controlling the robot by storing step-like commands alternately in two FIFO memories and adding them together may limit the operating speed depending on the acceleration/deceleration distance and step size, or the had a problem with the robot not stopping.

[0005] While there is an operation in the direction of movement, an acceleration/constant speed command is generated in that direction, and when there is no more operation, a deceleration command is generated to stop the robot. However, when attempting to change the direction of movement, If a different direction command is generated without stopping the robot, infinite acceleration will be applied in a specific direction, which will cause vibrations that will have a negative impact on the robot.
Normally, the robot would be stopped once and then a command for another direction would be generated.

An object of the present invention is to easily move a hand effector of a robot smoothly in any direction and to change the trajectory smoothly during the movement.

[0007]

[Means for Solving the Problems] The above object is to have a filter means using software that smooths direction commands on the generated orthogonal coordinate system, and to generate motion paths when remotely controlling a robot for teaching work, etc. The means generates a direction command on an orthogonal coordinate system that causes the robot to move by a fixed amount in each direction at minute fixed intervals in response to the operation input, and the filter means smoothes this direction in each direction in space. By converting it into a direction command, multiplying it by an appropriate speed amount, generating a position command from this, converting it to the coordinate system of each joint of the robot, and controlling the robot to this generated joint position. achieved.

[0008]

[Operation] The present invention utilizes a software filter means of a robot control device, especially when remotely controlling a robot for teaching work, etc., to generate a fixed direction or speed command in the motion path generating means. be.

[0009]

[Embodiment] An embodiment of the present invention will be described below with reference to FIGS. 1, 2, and 3.

FIG. 1 shows an embodiment of a robot control device according to the present invention, which has two drive shafts for horizontal movement and one drive shaft for vertical movement at its operating tip. FIG. 2 is a block diagram of a robot and its control device. In the figure, 101 is a motor attached to the base of the robot and rotates the first arm, 102 is a motor attached to the first arm and rotationally drives the second arm, and 10
Reference numeral 3 designates a vertical drive motor that is mounted on the second arm and drives the spline shaft up and down using a ball screw. 104 is an input/output circuit of the control device; 105 is a computer that executes programs and performs various calculations; and 106 is a computer that stores the current angles of each joint, speed setting values during remote control, and variables for filter calculations. 107 is an interrupt signal generation circuit that supplies an interrupt signal to the computer 105 at regular minute intervals in order to give commands to the servo circuit at regular minute intervals;
Servo circuits 08 to 110 control each arm of the robot by always following the rotation angle command for each motor sent from 105 at regular minute intervals. 11
Reference numeral 1 denotes an operating device that has a total of six switches in each of the X, Y, and Z directions of the orthogonal coordinate system, one in the positive direction and one in the negative direction, to determine in which direction the position of the hand effector of the robot is to be moved during remote control. When the instructor remotely controls the robot using the operating device 111, the computer 1
05, and the computer 105 gives motor rotation angle commands to the servo circuits 108 to 110 at minute intervals. Servo circuits 108 to 110 always control each arm to the rotation angle of the motor given by computer 105.

FIG. 2 shows a flowchart for generating rotation angle commands for each joint according to the present invention. The flowchart in FIG. 2 shows the interrupt signal generation circuit 10 in FIG.
It is activated at regular minute intervals by the interrupt signal No. 7, and completes its processing by the next interrupt signal. In the figure, reference numeral 201 denotes an operation amount input means, which obtains the state of the switch operated by the operating device 111 through the input/output circuit 104 in FIG. 202 is a vector creation means for each direction, and assuming that two switches in the X positive direction and Y positive direction are currently pressed in the operating device 111, the magnitude is 1 and the direction is a unit vector in the X positive direction and a unit vector in the Y positive direction. A unit vector (0.7071, 0.7071, 0) is generated by adding the direction unit vector. Reference numeral 203 denotes a filter means, which receives the vector generated at 202 as input and generates a smoothed output by filter operation in each of the X, Y, and Z directions of the orthogonal coordinate system. 204
is a movement amount generating means, which multiplies the amount for each direction generated in step 203 by a constant speed amount. The operating speed of the robot is determined by the amount of speed multiplied by the speed and the small constant time interval at which the interrupt signal is received. Reference numeral 205 is an orthogonal coordinate system position command generation means after a minute time, which adds the amount of movement in each direction after a minute time generated in 204 to the current position of the hand effector of the robot on the orthogonal coordinate system. Generates a position command after a short time. 206 is a coordinate transformation means;
The position command on the orthogonal coordinate system generated in step 05 is converted into a rotation angle command for the motor attached to each joint of the robot. 207 is a servo circuit transfer means for transferring the motor rotation angle command obtained in 206 to the servo circuits 108-110.

FIG. 3 is a diagram showing the input/output relationship of the filter means 203 in FIG. 2, and shows changes in the output when a constant input is applied. The vertical axis shows the input/output values, and the horizontal axis shows the output results from the first time to the kth time. Normally, a first-order lag system simulation using software is used for the filter means, and the time constant of the first-order lag system is appropriately determined so as not to generate vibrations in the robot, and is commonly used for the filter means in each direction. Since processing is performed by software with the same time constant, there is no offset that occurs in hardware circuits, and output can be obtained in each direction in the direction desired by the operator.

In this embodiment, the shape of the switch of the operating device of FIG. 1 is not important. In this embodiment, six switches are used to specify the direction of operation, but if an operating device that can sequentially specify each direction can be created, it will be possible to remotely control the robot in the desired direction.

As described above, in the control device as shown in FIG. 1, if the filter means having the characteristics shown in FIG. 3 is used during remote operation such as teaching work, and the flowchart of FIG. It is possible to easily operate the robot's hand effector and smoothly change the trajectory even in the middle of the operation.

[0015]

[Effects of the Invention] A robot having multiple motion axes has a software filter means for smoothing the generated direction or speed command on the orthogonal coordinate system, and allows an operator to remotely control the robot for teaching work, etc. In this case, a direction or speed command on an orthogonal coordinate system that causes the robot to move in a certain direction is generated, and then converted into a smooth direction or speed command for each direction in a two- or three-dimensional space by the filter means. By controlling each movement axis of the robot with this smooth direction or speed command, it is possible to smoothly move the robot's hand effector in any direction and change the trajectory smoothly even in the middle of movement. realizable.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a robot and its control device, which is an embodiment of the robot control device according to the present invention.

FIG. 2 is a flowchart for generating rotation angle commands for each joint of the robot according to the present invention.

FIG. 3 is a diagram showing the input/output relationship of the filter means included in the present invention.

[Explanation of symbols]

101 First arm rotation drive motor 102
Second arm rotation drive motor 103 Vertical drive shaft motor 104 Input/output circuit 105 Computer 106 Memory circuit 107 Interrupt signal generation circuits 108 to 110 Servo circuit 110 Operating device 201 Operation amount input means 202 Each direction vector generation means 203
Filter means 204 Movement amount generation means 205 Cartesian coordinate system position command generation means 206
Coordinate conversion means 207 Servo circuit transfer means

Claims (1)

[Claims] 1. A robot having a plurality of motion axes, comprising software filter means for smoothing a generated direction or speed command on an orthogonal coordinate system,
When a worker remotely controls a robot for teaching work, etc.,
A direction or speed command on an orthogonal coordinate system that causes the robot to move in a certain direction is generated, and it is converted by the filter means into a smooth direction or speed command for each direction in a two- or three-dimensional space. 1. A robot control device that controls each motion axis of a robot using specific direction or speed commands.