JPS6214209A - industrial 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 Field of Industrial Application The present invention particularly relates to an industrial robot such as a vertical articulated link type robot in which a prime mover and an arm are directly connected.

BACKGROUND OF THE INVENTION In recent years, in the field of controlling industrial robots, high-speed positioning and high-speed work tact are required, and various high-speed positioning methods are being put into practical use.

An example of a conventional one-type deviation counter will be described below with reference to the drawings.

4 and 6 are block diagrams and speed command curves of a conventional one-type deviation counter.

In FIG. 4, 51 is an arithmetic unit that issues a position command.

62 is an up/down counter that counts the amount of deviation between the position command pulse and the feedback pulse. 53 is a digital/analog converter that converts the deviation amount into a motor command voltage. 54 is a servo motor drive circuit.

66 is a servo motor. 56 is a load.

57 is a pulse generator for position detection.

The operation of the servo control circuit configured as described above will be explained below.

F/V where command pulses are input from the calculation unit to the two-way circuit
The converter converts it into an analog voltage and activates a pulse in the deviation counter.

This pool of pulses is converted into an analog voltage by a digital-to-analog converter, which then becomes a speed command and the motor starts rotating.

At the same time, an optical position detection pulse generator 1 attached to the opposite side pressure of the motor generates a pulse proportional to the N rotation angle and subtracts the accumulation on the deviation counter.

FIG. 6 shows a diagrammatic representation of the relationship between the motor speed and the command pulse.

The conventional example is described in [Sensor Technology, J April 1983 issue (V
O1!3 Melon 4) Shown on pages 39 to 42.

Problems to be Solved by the Invention However, with the above configuration, there is no circuit or sensor that can detect the load weight relative to the motor load, so there is a problem that optimal high-speed positioning cannot be performed when the load weight changes. Ta.

In view of the above problems, the present invention detects the load weight and realizes optimal high-speed work. .

Means for Solving the Problems In order to solve the above problems, the present invention uses a moving coil type motor that drives a robot arm, and a current system that generates position coordinates by counting the output from a sensor directly connected to the motor. The robot arm is equipped with an arithmetic circuit that determines the load weight attached to the robot arm from the position detection N path and the speed arithmetic circuit.

Function: With the above-described configuration, the present invention can automatically change the acceleration and deceleration curves by changing the load weight attached to the tip of the robot sotoam, and is particularly useful for increasing the work tact and movement speed of direct drive type robots. Embodiment Hereinafter, an optimal control system according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a mechanism for performing optimal control in a first embodiment of the present invention.

6... In Fig. 1, 1 is a two-axis linear motor, 2 is a Z-axis linear sensor, and 3 is an X-axis linear motor, and each axis uses a moving coil type motor. 4 is an X-axis near sensor, 6 is a Y-axis near motor, and 6 is a Y-axis near seven sensor, which detects the position of the movable part of the moving coil type motor provided on each axis. 7 is a robot arm, and 8 is a knot τ. FIG. 2 is a block diagram of a control device that controls the mechanism section.

9 is an arithmetic unit that performs optimal control of the robot arm; 10 is an up/down counter that counts the amount of deviation between the position command pulse and the feedback pulse; 11 is an F/V converter for feed forward; and 12 is a converter that converts the deviation amount into a motor command voltage. 13 is a servo motor drive lrl path, 14 is a servo motor, 15 is a load, 16 is a pulse generator for canning, 17 is a Schmitt circuit, 18 is an F/V converter for speed feedback, 19 is the current position counter.

The operation of the robot arm and control circuit constructed as described above will be explained below with reference to FIG.

Figure 3 shows a chart from step 70 until the optimum movement speed of the robot arm is determined.

First, when a drive start input signal is input to the calculation section 9 by a drive start input means (not shown), the microcontroller of the calculation section calculates the current position counter 19, position command pulse amount, and servo rigidity as follows. Calculate the load weight using the formula shown.

y=(ba-a)・K,C y: Load weight (K2) a: Current position data b: Position command data: Servo rigidity system C: Load weight system After that, the calculated load weight and arm position of the load This is the value that determines the optimal slow amp curve, slow down curve, and maximum speed depending on the direction of movement.

As for K, which determines the maximum speed of the slow-up curve and slow-down curve, the gain of the proportional term of the motor's servo rigidity has an optimal value for the load inertia and the motor constant, and is stored in the calculation section. You can select from multiple values.

This is for the purpose of accelerating in a short time and improving f1 takt.

Next, a circuit for automatically adjusting the load weight by the robot arm and the control device and the optimum servo stiffness stored in the calculation section are inputted to the calculation section as external variable inputs.

Depending on the input data, a slow-up value is selected, a high speed is selected, a slow-down is selected, and the value is output from the calculation unit as a position command pulse.

Additionally, multiple values of servo stiffness, slow-up, and maximum speed. Instead of the storage section inside the slowdown various value V support calculation section, a dedicated storage device may be attached externally.

By combining the above devices, the robot and robot control device of the present invention can perform vibration-free positioning operations at high speed without being affected by changes in load weight at any time.

Effects of the Invention As described above, the present invention provides a current position detection system that generates position coordinates by counting the output from a robot arm, a moving coil type motor that drives it, and a position detection scale that detects the position of the movable part of the motor. By providing a circuit and an arithmetic circuit that determines the load weight attached to the robot arm based on the current position and servo rigidity, the robot arm's movement speed, slow-up, and slow-down curve can be varied according to changes in the amount of load. It is possible to improve work tact and complete positioning without vibration of the robot arm.

[Brief explanation of drawings]

FIG. 1 is a robot mechanism diagram for realizing optimal control in a first embodiment of the present invention, and FIG. 2 is a block diagram of a robot control device of the same embodiment. Figure 3 is a flowchart diagram for realizing optimal control.
Figure 4 is a block diagram of a conventional robot control device; Figure 6 is a block diagram of a conventional robot control device;
The figure shows the deviation of command pulses. 9
......Arithmetic circuit, 19...Current position detection circuit, 1o...Speed calculation circuit, 13...
・Drive amplifier circuit. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
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Claims (1)

[Claims] A robot arm, a moving coil type motor installed on a shaft that supports the load weight attached to the tip of the robot arm, a position detection sensor that detects the position of the movable part of the moving coil type motor, and driving the moving coil type motor. A driving amplifier, a speed calculation circuit that issues a speed command to the driving amplifier, a current position detection circuit, a speed calculation circuit, and a current position detection circuit that count the output from the position detection sensor and generate position coordinates. An industrial robot equipped with a positioning calculation circuit that detects a load weight attached to an arm and changes an acceleration curve and a deceleration curve for positioning control of the robot arm.