JPS6324402A - Locus control device for robot - Google Patents

Abstract

PURPOSE:To increase a locus accuracy while a robot is operated at a high speed by counting the rotating position of respective axes of motors with the first arithmetic processor, counting the position of a present arm tip and inputting the data of the position of an arm tip to add the correction to a target value toward the first arithmetic processor. CONSTITUTION:The first arithmetic processor 3 converts the data of the position of an arm tip inputted from a main processor 1 to the data of the rotating position of respective axes of the joints of a robot. The data of the rotating position of respective axes counted by the first arithmetic processor 3 are sent to a servo processor 6 as the command data of the rotating position. The servo processor 6 compares with the data of the rotating position detected by an encoder 10 based upon the command data of the rotating position of respective axes, the arithmetic processing is executed so as to follow the command data and the arithmetic result is sent to a servo amplifier 7 as the speed command signal. The servo amplifier 7 compares with the speed signal detected by a tachogenerator 9 based upon the speed command signal and drives a motor 8 so as to follow the speed command signal.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF THE INVENTION The present invention relates to a robot trajectory control device for controlling the trajectory of a robot at high speed and with high precision.

BACKGROUND OF THE INVENTION In recent years, robot control devices have been required to operate the robot at high speed and with high precision. Trajectory control for general industrial robots involves a microcomputer analyzing and processing pre-stored motion programs.
The servo system is configured to calculate the interpolated position by interpolating the position data of the arm tip, convert it to the rotational position data of the motor of each axis of the robot's joints, and follow the rotational position data. It drives the motor.

An example of the above-mentioned robot trajectory control device will be described below with reference to the drawings.

FIG. 3 shows a configuration diagram of a conventional robot trajectory control device. In FIG. is a servo amplifier, 8 is a motor, 9ij is a tachometer generator, and 10 is a d encoder. Servo amplifier 7I motor 8I tachometer generator 9. It is assumed that there are a plurality of encoders 1o depending on the number of axes of the robot.

The operation of the robot trajectory control device configured as described above will be described below. 31, the memory 2 stores a robot operation program taught in advance. When operating the robot as taught, the main processor 1 reads the operating program, performs υ analysis processing, and performs interpolation calculations. The interpolated position data is sent to the processor at regular intervals.

The arithmetic processor 5 converts the interpolated position data into rotational positions t'7:)j-y of the respective axes of the joints of the robot. Calculated by the calculation process 5. The rotational position data of the first draw is passed to the servo processor 6 as rotational position jQ command data. The servo processor 6 outputs the encoder 10 based on the rotational position of each axis and the commands C and τ.
The data on the rotational position detected by h and the calculation result are sent to the servo amplifier 7 as a speed command signal. Based on the speed signal detected by the tacho generator 9, the motor 8 is driven to follow the speed command signal.The servo processor 6 performs arithmetic processing on a plurality of 4111 and sends speed command signals to multiple servo amplifiers.

Problems to be Solved by the Invention However, in the above configuration, the burden of checking whether the motor 8 is moving according to the command value is transferred from the calculation processor 6 to the servo processor 6, which has the largest amount of calculations. Since the time interval between commands for the rotational position to be given becomes long, the tip position of the robot's arm is not fed back during operation, and the followability is determined by the servo processor 6, servo amplifier 7I motor 8I tachometer generator 9. It depends on the servo system composed of the encoder 10. Therefore, if the gain of the servo system is low or if it is greatly affected by gravity, the accuracy of the trajectory may not be maintained. In particular, robot servo systems have problems with vibration, so the gain cannot be set very high. Additionally, there were times when it was not possible to make instantaneous decisions, such as when the vehicle hit an obstacle.

Means to solve the problem In order to solve the above problem, the trajectory of the robot of this research f
The li control device calculates the rotational position of the motor of each axis from the data of the position of the tip of the robot's arm. a second calculation processor that calculates the position of the tip of the robot's arm from the rotational position of the motor of each axis; , calculate the difference between the data of the actual position of the tip of the robot's arm calculated by the second calculation processor and calculate the difference between the data and the actual position of the tip of the robot's arm calculated by the second calculation processor. The robot arm is added to the position and inputted to the first aI calculation processor as data on the position of the tip of the robot arm to be moved.

According to the above-described configuration, the present invention calculates the rotational position of each axis of the motor with the first processor (while calculating the entire current position of the arm tip with the second processor, and calculates the rotational position of each axis of the motor with the second processor) Since the corrected arm tip position (i) data is input to the first calculation process 2, it is possible to increase the accuracy of the trajectory while operating the l'l bond at high speed. 7. Embodiment 7 A robot trajectory control device according to an embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration diagram of a robot trajectory control device according to an embodiment of the present invention. In FIG. 1, 1 is a main processor, 2 is a memory, 3 is a first arithmetic processor, 4 is a second arithmetic processor, 6 is a servo processor, 7 is a servo amplifier, 8 is a motor, 9 is a tacho generator, 10 is an encoder. Servo amplifier 7, motor 8° tacho generator 9. It is assumed that there are a plurality of encoders 10 depending on the number of axes of the robot.

The operation of the robot trajectory control device configured as described above will be described below with reference to FIG. 1. First, a robot operation program taught in advance is stored in the memory 2. When operating the robot as taught, the main processor 1 reads the operating program, analyzes it, and performs interpolation calculations. The second arithmetic processor 4 receives from the servo processor 8 the data of the rotational position of the motor 8 inputted by the servo processor 6 to the encoder 10, calculates the current position of the arm tip, and sends it to the main processor 1. The main processor 1 calculates the current arm tip position data by proportionally calculating the arm tip position data that was previously interpolated and the current arm tip position data that is also output from the second calculation processor 4. and the value is added to the first arithmetic processor 3.
send to If the difference between the arm tip position data and the current arm tip position data output from the second arithmetic processor 4 is larger than a predetermined value, it is determined that there is an abnormality and the operation is stopped. The first arithmetic processor 3 converts data on the position of the tip of the arm inputted from the main processor 1 into data on the rotational position of each axis of the joints of the robot. The rotational position data of each axis calculated by the first arithmetic processor 3 is sent to the servo processor 6 as rotational position command data. The servo processor 6 detects the rotational position of each axis using the encoder 10 based on the command data of the rotational position of each axis.
,, it is compared with the rotational position data, and arithmetic processing is performed so as to follow the command data, and the result of the calculation is sent to the servo amplifier 7 as a speed command signal. The servo amplifier 7 compares the speed command signal with the speed signal detected by the tacho generator 9 based on the speed command signal, and drives the motor 8 so as to follow the speed command signal. The servo processor 6 performs arithmetic processing on multiple axes and sends speed command signals to multiple servo amplifiers.

FIG. 2 shows an operation flowchart of the robot trajectory control device having the configuration shown in FIG.

As described above, according to this embodiment, the first arithmetic processor calculates the rotational position of the motor of each axis from the data of the position of the tip of the robot's arm, and while the first arithmetic processor is performing the calculation, It is equipped with a second calculation processor that calculates the position of the tip of the robot arm from the rotational position of the motor of each axis at any given time, and the first calculation processor calculates the position of the tip of the robot arm using interpolated data. In order to follow the position data, the second calculation Bromo calculates the proportional value of the difference between the previously calculated position of the robot arm tip and the interpolated data of the robot arm tip position. By adding the data to the position of the tip of the robot's arm calculated by the second processor and inputting the data to the first processor as the position data of the tip of the robot's arm, the accuracy of the trajectory can be increased while operating the robot at high speed. It is also possible to instantly determine abnormalities such as when the vehicle hits an obstacle.

Effects of the Invention As described above, the present invention particularly provides a first arithmetic processor that calculates the rotational position to which the motor of each axis should be moved from data on the position of the tip of the robot's arm. a second arithmetic processor that calculates the actual position of the tip of the robot arm from the rotational position of the motor of each axis while performing calculations or at any time; A value obtained by proportionally calculating the difference between the position data of the tip of the robot's arm and the data of the actual position of the tip of the robot's arm calculated by the second calculation processor is calculated by the second calculation processor. By adding the data to the actual position of the tip of the arm and inputting it to the first processor as data on the position to which the tip of the robot's arm should move, it is possible to operate the robot at high speed while improving trajectory accuracy. It is possible to instantly determine abnormalities such as when the vehicle hits an obstacle.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a robot trajectory control device according to an embodiment of the present invention, FIG. 2 is a flowchart of the operation of the robot trajectory control device configured as shown in FIG. 1, and FIG. 3 is a diagram of a conventional robot trajectory control device. FIG. 2 is a configuration diagram of a trajectory control device. 3...First arithmetic processor, 4...Second arithmetic processor.

Claims (1)

[Claims] a robot having N degrees of freedom; a motor for driving each axis of the robot; a position detection means for detecting the rotational position of the motor; a speed detection means for detecting the speed of the motor; In a robot trajectory control device comprising a robot control section which inputs the output of a speed detection means and controls and drives the motor, the movement of the motor of each axis is determined from the input data of the position of the tip of the arm of the robot. A first arithmetic processor that calculates an exponent rotational position, a second arithmetic processor that calculates the position of the tip of the arm of the robot from the actual rotational position of the motor of each axis, and an arithmetic processor that calculates the position of the tip of the robot arm based on the actual rotational position of the motor of each axis; proportionally calculating the difference between data on the position of the tip of the robot's arm calculated by the second calculation processor and data on the actual position of the tip of the robot's arm calculated by the second arithmetic processor;
This value is added to the data of the actual position of the tip of the robot's arm calculated by the second arithmetic processor and sent to the first arithmetic processor as data of the position to which the tip of the robot's arm should move. 1. A robot trajectory control device, comprising: a processor for inputting data.