JPH0121748Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for restarting an industrial robot, and more particularly, to an apparatus for restarting a robot that has stopped due to a power outage quickly, reliably and safely after the power is restored.

In recent years, industrial robots have been used in various manufacturing processes, such as welding robots in automobile assembly plants, which are well known and are extremely effective in tasks that involve repeated simple movements.

This type of industrial robot repeatedly performs operations according to predetermined operation steps set in advance in a robot control circuit.

Generally, industrial robots use various motors as their driving sources, and therefore have the unavoidable drawback that their functions stop in the event of a power outage. Conventionally, when such an operation is stopped due to a power outage, the robot returns to its original position when the power is restored and performs the predetermined operation steps again.

However, such a restart method requires unnecessary repetition of operations when the power is restored, so improved conventional devices memorize the operating steps at the time of the power outage (immediately before) and perform operations based on this memorized information when the power goes out again. A method is adopted in which the robot is restarted by the robot, thereby making it possible to eliminate unnecessary repetitive operations. However, with such improved conventional devices, if there is no positional shift between the time the robot stops and when the robot restarts, it can operate well, but if the robot's position shifts while the robot is stopped. If the robot is moved manually by the operator, there will be a large difference between the robot position at the time of restart and the operation steps memorized at the time of power outage. A situation has arisen in which the operation steps remaining at the time of the power outage are started, which prevents the robot from operating correctly and there is a risk that the robot will collide with surrounding equipment or workpieces.

The present invention has been devised in view of the above-mentioned conventional problems, and its purpose is to provide an improved restart device that can quickly, reliably and safely restart the system after recovery from a power outage. In order to achieve the above object, the present invention includes a current position detector that electrically detects the current position of the robot, a power outage position memory that stores the robot position at the time of a power outage, and a power outage position memory that stores the robot's position at the time of a power outage. a subtracter that subtracts the outputs from each other to find the difference between the robot's current position and the power outage position;
A comparator that compares the output of the subtracter with a predetermined set value and outputs a comparison signal to the robot control circuit; The robot continues to move from its current position to the remaining process,
The present invention is characterized in that it includes a robot control circuit that stops the robot on the spot if the difference exceeds a predetermined value.

Preferred embodiments of the present invention will be described below based on the drawings.

The figure shows an embodiment of the restart device according to the present invention, in which a robot body (not shown) is controlled by a robot control circuit 10, and desired operation steps are stored in the robot control circuit 10. Then, the robot body repeatedly continues the desired work based on this operation step.

In the present invention, the current position of the robot body, particularly its working arm, is constantly detected, and for this purpose a current position detector 12 is provided. The current position detector 12 in the embodiment is a 1 provided at the joint of the working arm.
The current position of the robot is electrically detected by the potentiometer 14, and in the embodiment, this current position signal is converted into a digital signal by an AD converter 16. After that, the data is stored in the buffer memory 18, and the contents of the buffer memory 18 are sequentially updated in accordance with the movement of the robot. Of course,
As the current position detector 12, it is also possible to provide another absolute value detection encoder instead of the potentiometer 14.

In the present invention, a power outage position memory 20 is provided separately from the current position detector 12, and the power outage position memory 20 in the embodiment is composed of a register, and the input of this register 20 has the current position detected. A current position digital signal is supplied from the AD converter 16 of the device 12, and a write stop signal is supplied to its inhibit gate. This write stop signal is supplied from the OR gate 22, and the input of the OR gate 22 is the initial processing signal 100.
and a power outage detection signal 200. Therefore, writing to the power outage position memory 20 is stopped while the initial processing of the robot is being performed and during a power outage, so that the robot position at the time of power outage is memorized and held. The current position detector 1
The output of this detector 12 is directly supplied to the robot control circuit 10 and used to carry out predetermined stored operation steps.
Both outputs are supplied to a subtracter 24, and the difference between the two is determined. During normal operation, both inputs of this subtracter 24 match, and as a result, the output of the subtracter 24 is 0, and even during a stop due to a power outage,
If the robot maintains this stop position and there is no position shift or artificial movement, there will be no difference between the two inputs and a signal of 0 will be output from the subtracter 24. If a positional shift occurs in the robot or if the robot is artificially moved while the robot is stopped, such positional shift and movement will be tracked by the current position detector 12, but the position memory at the time of power outage will 20 stores only the position at the time of power outage, a difference occurs between both inputs of the subtracter 24, and this is output as is. The output of the subtractor 24 is fed to one input of a comparator 26 and compared with a set value from a setter 28 fed to the other input, thereby determining whether the displacement or movement is due to the displacement or movement. A determination signal indicating whether the amount of deviation exceeds a predetermined set value is output from the comparator 26, and is supplied to another input of the robot control circuit 10.

Therefore, the robot control circuit 10 can perform predetermined control according to this comparison output. That is, in the present invention, the robot control circuit 10 can recover from power outage if the amount of deviation of the robot is within a predetermined value. Later, the remaining operation steps are performed from that position, and if the amount of deviation exceeds a predetermined value, the robot is stopped on the spot.

As described above, according to the present invention, when a power outage is stopped, the robot's position at the time of power outage and its current position are constantly calculated, the difference between the two is monitored, and only when this difference is within a predetermined value, the robot is Since the robot operation is controlled to advance to the remaining operation steps from the power outage, and in other cases the robot is controlled to return to the home position, if the robot has not shifted or moved during the power outage, It performs efficient control without unnecessary repetition, and when there is any positional deviation or movement, it stops on the spot and manually restarts the operation from the origin position, thereby achieving efficient control. Enables highly safe robot control.

[Brief explanation of the drawing]

The figure is a block diagram showing a preferred embodiment of the restart device according to the present invention. 10... Robot control circuit, 12... Current position detector, 20... Position memory at power outage, 24... Subtractor, 26... Comparator, 28... Setting device.

Claims (1)

[Scope of utility model registration request] A current position detector that electrically detects the robot's current position; a power failure position memory that stores the robot position at the time of a power outage; and a power outage position memory that subtracts the outputs of the detector and memory from each other to determine the robot's current position and power outage position. a subtracter that calculates the difference between the robot's current position and the power outage position; a comparator that compares the output of the subtracter with a predetermined setting value and outputs a comparison signal to the robot control circuit; a robot control circuit that causes the robot to continue operating from the current position toward the remaining process when the difference is within a predetermined value, and stops the robot on the spot when the difference exceeds the predetermined value. An industrial robot restart device characterized by: