JPH04289086A - Manipulator controller - Google Patents

Abstract

PURPOSE:To complete origin detection work reliably, in a controller for manipulators such as a welding robot, a positioner and a slider, by deactivating a rotating prohibition signal from an operating limit detector used as an origin switch to prevent knocking and deviation failure at the time of origin detection work. CONSTITUTION:A shut-down circuit 6 is provided which shuts down the operating signals of an operating limit detector 4 from being inputted into a servo-motor control means 3 in a prescribed direction for origin detection work by driving respective operating members 1 of a manipulator in the direction upon receiving a starting command for origin detection work.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for controlling manipulators such as welding robots, positioners, and sliders.

0002

2. Description of the Related Art Usually, operating limit detectors (for example, limit switches) are provided at operating limit positions at both ends of the operating range of each operating member of a manipulator.

[0003] One of the operating limit detectors is also used as a mechanical origin detector (hereinafter referred to as an origin switch),
JP-A-58-186585 discloses a technique in which, after the origin switch is activated, the electrical origin is detected by the position detector of each operating member during movement in the opposite direction.

In other words, when adjusting the origin of the manipulator,
Move the operating member of the manipulator in the direction of the operating limit detector, which also serves as the origin switch, and once the origin switch is activated, move the operating member in the opposite direction (away from the origin switch) to turn off the origin switch. The electrical origin is detected by detecting the timing when the

In this prior art, when the origin switch is turned on during origin alignment, it operates as a normal operating limit detector (generating a forward rotation prohibition signal or a reverse rotation prohibition signal), and the operating members of the manipulator are To prevent movement in the direction of the home switch, a safety interlock is provided in the servo control circuit that prevents motor output in that direction while the home switch is on.

[0006]

[Problems to be Solved by the Invention] However, in the prior art, as mentioned above, the interlock function is activated while the origin switch is operating, so no motor output can be performed in the direction of the origin switch. Knocking may occur in the driving operation of the operating member, or deviation may occur due to loads such as gravity. In such a case, a problem arises in that the predetermined target movement position control becomes impossible and the origin detection work cannot be completed.

[0007] The present invention aims to solve such problems, and during the origin detection work (original alignment), the rotation prohibition signal from the operation limit detector used as the origin switch is disabled, and the rotation inhibit signal is disabled. It is an object of the present invention to provide a control device for a manipulator that can reliably complete origin detection work without causing knocking or abnormal deviation.

[0008]

[Means for Solving the Problems] In order to achieve the above object, the manipulator control device of the present invention operates based on the operating state of an operating limit detector provided in each operating member constituting the manipulator. The device is equipped with a servo motor control means for stopping the drive output of each of the operating members in the operating direction of the limit detector, and the operating member is driven in a predetermined direction of the origin detection operation upon receiving a command to start the origin detection operation. The present invention is characterized in that it includes a cutoff circuit that cuts off input of the operating limit detector activation signal in that direction to the servo motor control means.

[0009]

[Operation] In the above-described manipulator control device of the present invention, when a command to start the origin detection work is received, the operating member is moved in a predetermined direction and the operation limit detector in that direction is activated. The cutoff circuit blocks input of the operating limit detector activation signal to the servo motor control means.

Therefore, even if the operating limit detector is in the operating state, the operating member can be driven in either the forward or reverse direction, thereby preventing knocking or deviation abnormalities due to loads such as gravity. Prevented.

[0011]

[Embodiment] A manipulator control device as an embodiment of the present invention will be explained below with reference to the drawings. FIG. 1 is a block diagram showing its configuration, and FIGS. 2 and 3 are flow charts and timing diagrams for explaining its operation. It is a chart.

[0012] The manipulator in this embodiment is as follows:
The robot includes a robot body and a peripheral device (for example, a positioner), and in this embodiment, a case in which the control target is a positioner that operates to hold a workpiece, which is an object of robot operation, in a predetermined position will be described.

In FIG. 1, reference numeral 1 denotes an operating member constituting a positioner, 2 a servo motor for driving the operating member 1, 3 a servo driver (servo motor control means) for controlling the operation of the servo motor 2, Reference numerals 4 and 5 designate operating limit detectors which become activated when the operating member 1 comes into contact with them, detect that the operating member 1 has reached its operating limit position, and output a rotation prohibition signal (operating signal).

In this embodiment, the operation limit detector 4 is provided at the reverse rotation limit position of the servo motor 2, and outputs a reverse rotation prohibition signal when activated, and also serves as an origin switch. On the other hand, the operation limit detector 5 is provided at the forward rotation limit position of the servo motor 2, and outputs a forward rotation prohibition signal when it is activated.

Further, the servo driver 3 is configured to stop the drive output even if there is a command signal for the operating member 1 in the operating direction when the servo driver 3 receives the reverse rotation/forward rotation inhibition signal from the operation limit detectors 4 and 5. It has become.

In this embodiment, reference numeral 6 denotes a cutoff circuit provided between the operating limit detector 4 and the servo driver 3, which functions as an origin switch. This cutoff circuit 6
The switch 6a blocks the input of the reverse rotation prohibition signal (operation signal) from the operation limit detector 4 to the servo driver 3 upon receiving a command to start the origin detection work from the robot control panel 7. and a timer circuit 6b that opens the switch 6a for a predetermined time (about 5 seconds) upon receiving a reverse rotation prohibition signal from the operation limit detector 4 in response to a command to start the origin detection work.

In this embodiment, the operating limit detector 4
and the timer circuit 6b, there is a switch 8 which is driven to close by a command to start the origin detection work from the robot control panel 7.
is interposed, and by closing the switch 8 only during the origin detection operation, the timer circuit 6b can operate upon receiving the reverse rotation prohibition signal.

The servo driver 3 receives the reverse rotation prohibition signal and forward rotation prohibition signal from the operation limit detectors 4 and 5, as well as the speed command signal and the forward and reverse rotation command signal from the robot control panel 7, and receives the servo driver 3. The driver 3 controls the operating state of the servo motor 2 based on these signals.

Further, as the servo driver 3, one may be used in which the speed command signal has ± characteristics and is set in the driving direction.

The operation of the apparatus of this embodiment constructed as described above will be explained below with reference to FIGS. 2 and 3.

When a command to start the origin detection work is output from the robot control panel [see FIG. 3(b)], in the device of this embodiment, the servo drive 3 starts the servo drive as shown in FIG. 3(a). The operating state of the motor 2 is controlled, and the operating member 1 begins to be driven in the reverse direction (step S1 in FIG. 2).
.

The operation member 1 is driven until the operation limit detector 4 is activated (turned on) (step S2 in FIG. 2).
, the operating limit detector 4 operates as shown in FIG. 3(c),
When the reverse rotation prohibition signal is output as shown in FIG. 3(e),
At the same time as the driving of the operating member 1 by the servo motor 2 is stopped, the timer circuit 6b in the cutoff circuit 6 is activated, and the switch 6a of the cutoff circuit 6 is opened for a predetermined time (step S3 in FIG. 2).

By opening the switch 6a in this manner, the reverse rotation inhibit signal input terminal of the servo driver 3 receives the reverse rotation inhibit signal from the operation limit detector 4, as shown by the solid line in FIG. 3(f). is blocked and cannot be input. In addition, during normal robot operation (other than during origin detection work), Figure 3
As shown by the chain line in (f), a reverse rotation prohibition signal is outputted from the cutoff circuit 6 and inputted to the servo driver 3.

After the driving of the operating member 1 is stopped, the operating member 1 is driven in the forward rotation direction by the servo motor 2 in order to perform the origin detection work (step S4). This drive is shown in Figure 3.
As shown in FIGS. 3(a) and 3(c), the process is continued until the operating limit detector 4 is turned off (step S5).

At this time, if it is determined in step S5 that the operation limit detector 4 is on, the timer circuit 6
Determine whether time has expired for b (step S6).
), if the time has not elapsed, the process returns to step S4, while if the time has elapsed, the switch 6a is closed and a reverse rotation prohibition signal is output to the servo driver 3 (step S7), and some abnormality occurs. shall be marked as such.

On the other hand, in step S5, the operating limit detector 4
If it is determined that the timer circuit 6b is turned off, the timer circuit 6b
is turned off, and the switch 6a is switched to the closed state (step S8).

Similar to the normal origin detection work, after the operation limit detector 4 is turned off, the first Z pulse signal (pulse signal output once per rotation) output from the encoder (not shown) is detected. Until detection (step S9
), and drives the operating member 1 in the normal rotation direction (step S10).
As shown in FIG. 3(d), the driving of the operating member 1 is stopped at the time when the Z pulse signal is detected (step S11), and that point is used as the electrical origin.

As described above, according to the manipulator control device of this embodiment, even when the operating limit detector 4 used as an origin switch is in the operating state, the reverse rotation prohibition signal from the operating limit detector 4 is not detected during the origin detection work. is cut off by the cutoff circuit 6 and becomes invalid, so the operating member 1 can be driven in either forward or reverse directions by the servo motor 2, ensuring that knocking and deviation abnormalities due to loads such as gravity are prevented. Therefore, the origin detection work can be completed reliably.

In the above embodiment, the present invention is applied to a positioner constituting a manipulator, but the present invention is not limited to this, and can be similarly applied to a robot body, a slider, etc. Thus, the same effects as in the above embodiment can be obtained.

[0030]

As described in detail above, according to the manipulator control device of the present invention, each operating member is driven in a predetermined direction of the origin detection operation in response to a command to start the origin detection operation, and
Since the circuit is configured to block input of the operating limit detector activation signal to the servo motor control means in that direction, rotation from the operating limit detector used as an origin switch is prohibited during origin detection work. This has the effect of making it possible to disable the signal and ensure that the origin detection work is completed without causing knocking or deviation abnormalities.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of a manipulator control device as an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of this embodiment.

FIG. 3 is a timing chart for explaining the operation of this embodiment.

[Explanation of symbols]

1 Operating member 2 Servo motor 3 Servo driver (servo motor control means) 4
Operation limit detector (origin switch) 5 Operation limit detector 6 Cutoff circuit 6a Switch 6b Timer circuit 7 Robot control panel 8 Switch

Claims (1)

[Claims] 1. Servo motor control for stopping the drive output of each operating member in the operating direction of the operating limit detector in response to the operating state of an operating limit detector provided on each operating member constituting the manipulator. In the manipulator control device, the control device for a manipulator is configured to drive each of the operating members in a predetermined direction of the origin detection operation in response to a command to start the origin detection operation, and send a motion limit detector activation signal in that direction to the servo motor control means. A control device for a manipulator, characterized in that it is equipped with a cutoff circuit that cuts off input to the manipulator.