JPS631688A - Robot controller - 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 relates to a so-called tracking robot in which a robot manipulator itself tracks a moving work object and performs a given work.

[Conventional technology]

FIG. 3 is a block diagram of a conventional tracking robot control device. In the figure, (1) shows the entire robot control device, and (2) shows the servo motors that drive each joint (3) of the robot manipulator. (4) also shows a position detector, (5) shows a conveyor on which workpieces are placed and transported, (6) shows a conveyor speed detector, and (7) shows a conveyor speed detector.
) means that the reference position (hereinafter referred to as the base) of the workpiece (hereinafter referred to as the work) on the conveyor is at a specific position on the conveyor (hereinafter referred to as the base).
This is a synchronizing signal generator that generates a signal of 1 when passing through a conveyor pace (hereinafter referred to as a conveyor pace). From (8), αQ is provided inside the robot control device (1), and (
8) is a program storage unit that stores a series of robot operations, (9) is a program execution unit that executes the program stored in (8), and (IQ is a unit that detects the ever-changing conveyor speed. , a conveyor transfer distance accumulator that accumulates the velocity (1) calculates the conveyor transfer distance (5) from the conveyor transfer distance accumulated in αq and the position data taught in advance.
), a workpiece position calculation section that calculates the position of the workpiece on
■Detects the ever-changing conveyor speed, predicts the conveyor speed in the near future from the past and current values of this speed, and calculates the predicted travel distance that the conveyor will move in a minute time from the present.Conveyor speed The prediction unit, υ, adds the predicted conveyor movement amount calculated by the conveyor speed prediction unit (a) to the workpiece position on the conveyor calculated by the workpiece position calculation unit (1), and corrects the workpiece position. Conveyor speed compensation unit, α→ is a manipulator coordinate conversion unit that calculates the movement amount of each robot manipulator so that the robot manipulator moves to the target position calculated by the conveyor speed compensation unit (to), α→ is manipulator coordinate conversion unit The movement amount of each robot manipulator calculated by section α→ and the position detector (
0Q is a positioning feedback control unit that outputs an error voltage for manipulator movement based on the position information input from 4), and 0Q converts the error voltage output from the positioning feedback control unit (G) into a servo motor drive M, current. This is the power amplification part that increases the power.

Next, the operation will be explained. Figure 4 shows the conveyor (5)
This diagram illustrates the positional relationship between the workpiece and the workpiece.

In Fig. 4, (5) is a conveyor on which a workpiece is placed and conveyed, (7) is a synchronization signal generator that generates signal 1 when a workpiece passes the conveyor base, and (a) to (a).
indicates the workpiece on the conveyor (5), and the workpiece is moved from the position (1) by the conveyor (5)? ■, It is transported to the fourth position. (A) to (4) are the work target positions on the workpiece, and these are the same point on the workpiece. Workpiece (1) indicates when the workpiece is on the conveyor base, Workpiece 2°C indicates the current position of the workpiece, and Workpiece (A) is the predicted position of the workpiece a minute time after the current position. Arrow (7) represents the amount of movement of the conveyor between (7) and ■. Represents the predicted amount of conveyor movement between Ya and (2).

The robot sequentially reads and executes commands stored in advance in the program storage unit (8), and consider a case where one of the commands executes a command to move to a target position on the workpiece. The workpiece at this time is being transported by a conveyor, and the robot must move to the target position Ng3 on the workpiece while following the movement of the conveyor.

First, when the workpiece is conveyed by the conveyor, the moment the workpiece passes the conveyor position (conveyor base),
A signal of 1 is generated from the synchronization signal generator (7), and this signal is input to the conveyor transfer distance accumulator αq. When this signal is input, the cumulative value of the conveyor transfer distance accumulator α0 is reset to zero. The conveyor transfer distance accumulator (IQ) after this reset is the conveyor speed detector (6
), the cumulative value of the conveyor transfer distance accumulator α1 is the conveyor movement 1 after the workpiece on the conveyor passes the conveyor pace, and this movement amount is indicated by the arrow in Fig. 4. Corresponds to Ya. The speed from the conveyor speed detector (6) is also input to the conveyor speed prediction unit (6), which predicts the conveyor measurement in the near future from the past and present speeds, and the conveyor moves from the present to a minute time. Calculate the predicted amount of movement that will occur.

This predicted movement amount corresponds to the arrow (b) in FIG.

Next, the program execution unit (
9), a command to move to the target position (goods) on the workpiece is read out, and the workpiece position calculation unit (11) adds the conveyor movement amount to the target position - within the workpiece on the conveyor base. The target position (c) on the current workpiece is calculated. Furthermore, the predicted movement amount (
(b) is added, the target position (1) after a minute time is calculated, and the robot moves toward the target position (1) until it reaches the target position. The tracking operation progresses as the amounts are calculated and added.

[Problem that the invention seeks to solve]

Since the control lid of a conventional tracking robot is configured as described above, tracking operations can be performed during automatic operation in which a program is decoded and executed, but tracking operations cannot be performed during so-called jog operation when the robot is operated manually. I couldn't do it. Therefore, if a problem occurs during automatic operation and you manually operate the robot and evacuate the robot to the outside of the conveyor, the conveyor may not be able to be stopped, or even if it is stopped, the conveyor will have inertia and will not stop immediately. At the time, there were problems such as interference between the workpiece on the conveyor and the robot, creating a dangerous situation.

The invention (') was made in order to solve the problems mentioned in 2. It is a control device for a robot that follows the movement of a conveyor not only during automatic operation but also during jog operation. The purpose is to obtain.

[Means for Solving Problem r]] The robot control device according to the invention 4' uses input from a workpiece position calculation section and a teaching box (equipped with a switch for manually operating the robot). The position calculation section is changed over by a switch, and speed compensation is always performed based on the speed of the conveyor f.

[For ear]

In the tracking operation according to the present invention, even when manual operation is performed using the teaching box, the pit always moves in synchronization with the conveyor by the speed compensator of the conveyor.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings. 1st
In the figure, (1) to αQ are exactly the same as those in the conventional example. ■ is a teaching box equipped with a switch for manual operation (hereinafter referred to as jog operation) of the robot, (9) is a switch for jog operation, and (b) is a teaching box that receives input signals from the teaching box. The signal input section, the supplementary one is a jog movement amount calculating section that determines the amount of movement of the robot based on the teaching signal, and the symbol (2) is a mode switching section that switches between automatic operation and jog operation.

Next, the operation of this invention will be explained. FIG. 2 illustrates the positional relationship between the conveyor and the workpieces. Second
In the figure, (5), (7), (a) to gradient, and @ are exactly the same as the same symbols in FIG. 4, which describes the operation of the conventional example. First of all, the work is 0! Assume that automatic operation is switched to jog operation when the vehicle is in position (3). The position of the workpiece after a minute time Δ from the workpiece position 01) is indicated by (a), and the position of the workpiece after a time of Δ is roughly indicated by a phrase. (6υ is the position of the robot when the workpiece is at position 02, and (support) is the position of the robot after Δ.Q is the conveyor prediction calculated when the workpiece is at position 4. The amount of movement, - is the amount of movement of the robot commanded by the teaching box (10) when the workpiece is at the position of (goods), the amount of movement that is the combination of the amount of movement l and -, ... is the amount of movement of the robot by the amount of movement -. Indicates the position of the robot when it moves.

The tracking operation when the workpiece is transported from position 4 to position (c) is exactly the same as in the conventional example, so below we will explain how to switch from automatic operation to jog operation when the workpiece is at position (b). I will explain what happens after the replacement.

Switching from automatic operation to jog operation is performed by an input signal from, for example, a switch external to the control device (not shown). When this signal is input, the flow of data in the mode switching section changes to work. The position calculation unit (11) switches to the jog movement amount calculation unit. The positions of the workpiece and the robot at this time are (C) and G]), respectively, in FIG.

If the time period Δ has elapsed without an input signal from the teaching box α0, the amount of movement calculated by the jog movement amount calculation section is O. The speed detected by the conveyor speed detector (6) is input to the conveyor speed prediction unit (6), and the predicted conveyor movement amount is calculated and the conveyor speed compensation unit (to)
The predicted conveyor movement distance (b) is calculated based on the current position of the robot.
is added, the robot's position after a time of Δ is determined to be the iron, and the robot moves to the iron position. If there is no input signal from the teaching box), the above operation is simply repeated.

When the robot moves to the point of the ring, the switch envelope ◇ attached to the teaching box (G) is pressed and the signal is input to the teaching signal input section (6). The amount of movement of the robot is calculated by a jog movement amount calculating section (6). The arrow - in FIG. 2 corresponds to this. Arrow Q
is the predicted movement amount calculated in the same manner as the conveyor predicted movement t@, and these two movement amounts are combined in the conveyor speed compensator (g), and the robot position after time Δ is (
b) is determined and the robot moves to the position shown in the figure.

The robot moves according to instructions from the teaching box (11) - Even if the robot moves in the same direction as the direction of injury, when the robot moves according to instructions from the teaching box, the robot moves by following the conveyor. Therefore, the command value from the teaching box (40) is the amount of movement relative to the workpiece. Therefore, when instructing the robot to move from the teaching box does not deviate from the work.

In the above embodiment, a teaching box (6) is provided to perform the jog operation, but a sensor or other external device may be used instead of the teaching box (6).

〔Effect of the invention〕

As described above, according to the present invention, a mode switching section for switching between automatic operation and jog operation is provided, and conveyor speed compensation is always performed, so that when switching from automatic operation to jog operation, However, since the robot moves by following the conveyor, it does not interfere with the workpiece during jog operation, and the robot can be moved safely.

[Brief Description of the Drawings] Fig. 1 is a configuration diagram of a robot control device according to an embodiment of the present invention, Fig. 2 is a diagram showing the positional relationship between a conveyor and a workpiece for explaining the present invention, and Fig. 6 is a conventional FIG. 4 is a diagram showing the positional relationship between a conveyor and a workpiece to explain a conventional example. In the figure, (5) is the conveyor, (6) is the conveyor speed detector, (7) is the synchronization signal generator, αq is the conveyor transfer distance accumulation unit, (6) is the conveyor speed prediction unit, and (to) is the conveyor speed. Compensation section, (6) is teaching box, ■ is mode switching section. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] In a tracking robot that performs work by following a moving workpiece, a speed detector detects the conveyance speed of the workpiece conveyance device, a synchronization signal generator detects when the workpiece passes a specific position on the conveyance device, means for detecting and storing the amount of movement of the conveyance device; means for predicting the conveyance speed in the near future from the conveyance speed of the conveyance device; means for switching between automatic operation and manual operation; and the conveyance speed predicted by the conveyance speed prediction means. 1. A robot control device comprising: means for correcting position data.