JPS59107882A - Controller for robot - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a robot control device FC, and more particularly to a robot control device that positions the robot at a commanded position accurately and reproducibly.

FIG. 1 shows a block diagram of a conventional robot arm control device. In FIG. 1, a command circuit 10 for controlling the robot arm is connected to a memory circuit 12 for storing control commands and data, and the output side of the command circuit has a drive for transmitting control commands to the drive unit of the robot arm. an amplifier 14, a motor 1 that moves the robot arm according to the command;
6 are connected in sequence. The drive amplifier 14 includes a position control circuit 18, a speed control circuit 20. Each of these circuits has comparators 24 to 2 on the input side.
It has 8. The comparator 24 compares the detection signal from the position detector 30 and the control command from the command circuit 10. Comparator 26 compares the detection signal from speed detector 32 and the output signal from position control circuit 18 . The comparator 28 compares the detection signal from the current detector 34 and the output signal from the speed control circuit 20.

Conventional robot control devices have the above configuration, and when processing or moving a workpiece placed on a work table using the mouth pot arm, the control device operates as follows. Become. Command circuit 10F to move the robot arm
i. Read data and control commands from the storage circuit 12 and transmit them to the drive amplifier 14. As described above, this drive amplifier 14 is composed of a position control circuit 18, a speed control circuit 20, and a current/current control circuit 22, so that the rotation amount, speed, etc. of the motor are driven based on the output of each of these circuits. Conditions are controlled.

The robot arm handles the weight of the workpiece when it is handled.
Since deflection occurs due to the weight of the robot %i, it is necessary to correct the values of the machining amount and movement amount input to the command circuit 10 using the program in the memory circuit 12 according to the amount of deflection. This correction was very difficult because it changed depending on the posture of the robot arm (it had the disadvantage that correcting it was troublesome and took a lot of time. It also had the disadvantage that position repeatability could not be obtained accurately depending on the feed rate, etc.) .

The present invention was developed in view of the above-mentioned conventional problems, and its purpose is to calculate the amount of deflection generated in the robot arm from the weight of the workpiece and the posture of the robot arm, and to calculate the amount of deflection generated in the robot arm based on the calculation result. The object of the present invention is to provide a robot control device that accurately corrects the machining amount and movement amount input in a program.

To achieve the above object, the present invention provides a command circuit that outputs a control command for controlling a robot arm, and a motor that drives the robot arm according to the control command. a detector, and a weight conversion circuit that converts the total weight of the hand and workpiece attached to the arm of the robot based on the detection signal from the current detector;
A deflection amount calculation circuit that calculates the amount of arm deflection based on the total weight applied to the arm of the robot given in advance, and movement commanded by the command circuit based on output signals from the weight conversion circuit and the deflection amount calculation circuit. The present invention is characterized by comprising a position correction circuit that calculates the amount of correction and supplies the calculated amount to the motor as a control command.

Hereinafter, preferred embodiments of the present invention will be described based on the drawings. FIG. 2 is a block diagram showing an embodiment of the present invention, and the same parts as in FIG. In FIG. 2, a position correction circuit 36 is provided between the command circuit 10 and the drive amplifier 14, and a deflection amount calculation circuit 38 that calculates the amount of deflection when the conditions for moving the robot arm are input, and a motor drive current. A weight correction circuit 40 which inputs the detection signal of the detector 34 and calculates a correction amount from the weight of the workpiece is connected to the position correction circuit 36''.

The embodiment of the present invention has the above configuration, and its operation will be explained below. The command circuit 1o reads data and control commands from the memory circuit 12 to move the robot arm, and transmits them to the position correction circuit 36.

At this time, the position correction circuit 36 is based on input signals from the deflection calculation circuit 38, which calculates the positional deviation resulting from the position and posture of the robot arm, and the weight correction circuit 4o, which calculates the weight of the workpiece from the motor drive current in the drive amplifier. The command data supplied from the command circuit 1o is corrected. This correction data is supplied to the drive amplifier 14J, which includes a position control circuit 18, a speed control circuit 20. Current control circuit 2
2 to the motor 16. Then, check whether the motor 16 is moving at the speed and position specified by the command value.
The rotation amount, speed, etc. of the motor 16 are controlled by detecting it with a speed detector 32 and a position detector 3o.

In the above embodiment, a case has been described in which the total weight can be corrected, but the present invention can also be applied to correction of expansion and contraction due to temperature changes in the robot's arm.

As described above, according to the present invention, the amount of deflection of the robot arm caused by the weight of the robot arm and the weight of the workpiece is automatically corrected. There is no need for troublesome correction processing, preparation time before work is greatly shortened, and accurate position reproducibility can be obtained without being affected by feed speed.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional robot arm control device, and FIG. 2 is a block diagram showing a mouth pot arm control device according to an embodiment of the present invention. Identical members in each figure are given the same reference numerals, and lO is a command circuit;
12 is a memory circuit, 14 is a drive amplifier, 16 is a motor, 1
8 is a position control circuit, 20 is a speed control circuit, 22 is a current control circuit, 30 is a position detector, 32 is a speed detector, 36 is a position correction circuit, 38 is a deflection amount calculation circuit, and 4'O weight correction circuit. It is. Agent Patent attorney Shin Kuzuno - (#1 or 1 person)

Claims (1)

[Claims] (1) A command circuit that outputs a control command to control the robot arm, and a motor that drives the robot arm according to the previous He control command.'M5 current detection that outputs four motor drive currents. A weight conversion circuit converts the total weight of the hand and workpiece attached to the robot's arm based on the detection signal from the current detector, and a weight conversion circuit that converts the total weight of the hand and workpiece attached to the robot's arm, and the total weight applied to the robot's arm given in advance. Output signals #' from the deflection calculation circuit that calculates the amount of arm deflection, the weight conversion circuit, and the deflection calculation circuit described above. F#: a position correction circuit that calculates a correction for the movement amount commanded from the command circuit and supplies it to the motor as a control command;
A robot control device comprising: