JPH01264782A - Controlling of servo-manipulator - Google Patents

Abstract

PURPOSE:To invariably operate a manipulator with the optimum thrust by setting the deviation limit value for the maximum thrust of the manipulator and stopping to update the next target coordinates when the deviation of the manipulator exceeds this limit value. CONSTITUTION:The preset acceleration incremental quantity is added or subtracted from the speed incremental quantity by a deviation calculating means so that a manipulator 30 is moved at the speed proportional to the displacement quantity detected by a displacement quantity detecting means. This speed incremental quantity is added or subtracted from the previous target coordinates by a deviation calculating means, the deviation is calculated based on the target coordinates newly updated by a target coordinates updating means and the present coordinates of the manipulator 30. When the deviation of the manipulator exceeds the deviation limit value, the updating of the new target coordinates in the same direction is stopped while this thrust is kept, and the manipulator 30 is moved to the target coordinates so that the proper thrust is obtained based on this determined thrust not to damage a controlled object and the manipulator 30.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable to pushing and moving workpieces with high frictional resistance, heavy workpieces, and workpieces that have obstacles on the movement path that obstruct the movement of the workpieces. This invention relates to a method of controlling a servo manipulator that is pulled and moved.

[Conventional technology]

As a control method for this type of servo manipulator, as shown in Japanese Patent Laid-Open No. 62-74586, a drive signal based on the positional deviation between the mask and the slave is applied to the servo actuator on the mask side and the torque actuator on the slave side, respectively. The apparatus is configured to include means for cutting off the drive means for the slave-side servo actuator in a control overload state, and means for lowering the level of the drive signal for the mask-side torque actuator.

[Problems to be Solved by the Invention] The conventional servo manipulator control method detects a control overload state, cuts off the thrust of the manipulator, and
By lowering the level of the drive signal, it is possible to prevent the manipulator from operating violently against the operator's will and damage to the manipulator and the workpiece at the same time as the operation starts after stopping. This is a method of cutting off thrust. Therefore, it is not possible to move workpieces with a lot of frictional resistance, heavy workpieces, or workpieces that have obstacles on the movement path that obstruct movement of the workpieces by constantly applying thrust or by pulling them. The problem was that it couldn't be done.

An object of the present invention is to provide a control method that operates according to the operator's intention when the manipulator is stopped and then restarted, while always producing an appropriate thrust.

[Means for solving problems]

In order to solve the above-mentioned conventional problems, the present invention provides a servo-based manipulator that pushes and pulls an object to be controlled. a speed increment calculating means for adding or subtracting a preset acceleration increment from the speed increment so that the manipulator moves at a speed proportional to the detected displacement; a deviation calculating means for adding or subtracting and calculating a deviation from the target coordinate newly updated by the target coordinate updating means and the current coordinate of the manipulator, and the deviation calculated by this deviation calculating means is applied to the controlled object and the manipulator deviation control means that stops updating new target coordinates in the same direction while producing the thrust while a preset deviation limit value is exceeded so as to be able to produce an appropriate thrust within a range that does not damage the , and a driving means for moving the manipulator to the target coordinates.

〔Example〕

FIG. 1 is an overall configuration diagram of an apparatus in an embodiment of the present invention. In the figure, reference numeral 1 denotes a conveyor, on which a workpiece (not shown), such as a casting product, is placed and conveyed in the direction of arrow A. Reference numeral 30 denotes a manipulator, which is installed above the conveyor 1 by means of a frame 2, and is connected to the traveling carriage 4 via the rail 3.
is mounted so as to be movable in the same direction as the conveyor 1, and constitutes a conveyor synchronization shaft. Next, a traversing truck 6 is placed on the conveyor 1 via the rail 5 so as to be movable in the right angle direction, and an operating shaft 7 is installed on the traversing truck 6 so as to be movable up and down. The sorting device is equipped with a wrist portion 9 that allows the plate 8 to rotate freely around an operating axis. Reference numeral 10 denotes an operation panel, which is provided with operation rings 11 and 12 and is electrically connected to a manipulator controller 13. Reference numeral 31 denotes an encoder for detecting the amount of movement of the conveyor 1, which is connected to the drive shaft 14 of the conveyor 1 via a chino, and is electrically connected to the manipulator controller 13. The manipulator 30 is installed so that its manipulator coordinate system is located at the position shown in the figure, and its conveyor synchronization axis, ie, the X axis, is parallel to the conveyance direction of the conveyor 1.

Referring now to FIG. 2, the method of the present invention will be carried out. The manipulator controller 13 includes a CPU 20, a memory 21,
A/D converter 22, D/A converter 23, parallel interface 24. It is composed of a U/D counter 25, a servo driver 26, a position converter 27, etc.

The CPU 20 provides the manipulator controller 13 with a displacement detection function, a speed increment calculation function, a target coordinate update function, and a deviation calculation function according to the present invention by executing various control programs stored in advance in the memory 21 and including programs to be described later. It is comprised of a random access memory (RAM) as a work memory necessary for controlling the manipulator 13, a deviation control function, a manipulator drive function, and the manipulator 13.

The A/D converter 22 converts the displacement amount generated by the control sticks 11 and 12 into a digital amount and stores it in the memory 21 as a displacement amount (command value). Convert to target coordinates.

The parallel interface 24 converts the current position of each axis of the manipulator 30 into relative position data using a position converter 27 from the encoder value of a position detection encoder attached to the actuator, and stores the converted data in the memory 21 as current coordinate data.

The U/D counter 25 stores encoder data from a position detection encoder 31 attached to the conveyor in the memory 21, and calculates the amount of movement of the conveyor 31 through processing described later.

The D/A converter 23 outputs the operation amount calculated from the difference between the target coordinates generated by the CPU 20 and the current value of each axis to the servo driver 26 as a speed command.

Next, the operation of the present invention will be explained in detail with reference to FIG. Third
The diagram shows the deviation calculated from the target coordinates and the current coordinates of the manipulator, and the D/A corresponding to the thrust of the manipulator.
FIG. 3 is a diagram showing the relationship between output values. In FIG. 3, the D/A output value increases as the deviation increases, but the increase stops after reaching a certain deviation level. The D/A output value at this time corresponds to the maximum outputtable thrust of the manipulator. The deviation limit value shown in FIG. 3 is a value set in advance by the operator within a range that does not damage the workpiece or manipulator, and has the purpose of suppressing the D/A output value. When the deviation exceeds this deviation limit value, the target coordinate update flag transmits the deviation limit value excess to the target coordinate update means section.As a result, the target coordinate update means section can set the target coordinates while the above flag is set. After stopping updating of the coordinates, if the flag is cleared or a displacement of the control stick occurs in a direction that reduces the deviation, updating of the target coordinates is resumed.

4 and 5 are flowcharts showing the processing procedure when controlling the manipulator based on the action shown in FIG. 3. FIG. The process shown in Fig. 5 is started at regular intervals by a timer interrupt, and the target coordinate update process shown in Fig. 4 is synchronized with the process shown in Fig. 5 using a synchronization flag. n times the startup interval time (n≧1
) at time intervals.

In this embodiment, a manipulator having three orthogonal axes and a wrist portion has been described as an example, but the present invention can be similarly applied to any type of manipulator.

〔Effect of the invention〕

Since the present invention has the structure and operation described above, it has the following effects.

(1) Set a deviation limit value that can produce the maximum thrust of the manipulator, and when the deviation of the manipulator exceeds the deviation limit value, the manipulator will stop due to an abnormal deviation in order to stop updating the next target coordinate. It is possible to always operate with the optimum thrust.

(2) In addition, since the next target coordinates are not updated as described above, even if a large amount of deviation does not accumulate and the load resistance of the workpiece that the manipulator receives suddenly decreases, the manipulator will suddenly move and become uncontrollable. The operation can be continued normally without any problems.

(3) Furthermore, since updating of the target coordinates in the opposite direction is accepted even after the deviation limit value is exceeded, a vertically flexible man-machine interface can be realized, for example, when a person operates using a control stick or the like.

(4) Furthermore, when the deviation limit value of the present invention is exceeded,
In addition to prohibiting the update of the next target coordinates, by additionally determining the time monitoring of this case, the worker can take an appropriate response,
It is also possible to automatically execute abnormality processing.

(5) Although the present invention describes a servo system maniplane using a control frame, it goes without saying that the present invention can also be applied to automatic robots that are taught in advance or that automatically calculate their trajectories.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the overall configuration of an apparatus in an embodiment of the present invention, FIG. 2 is a configuration diagram of a control device in an embodiment of the invention, FIG. 3 is a diagram explaining the operation of the present invention,
, 5 is a flowchart showing the processing procedure of the present invention. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Scope of Claims] 1. In a servo manipulator that moves a controlled object by pushing or pulling it, a displacement detection means detects the displacement amount and direction of a control stick, and detection by the displacement detection means a speed increment calculation means for adding or subtracting a preset acceleration increment to the speed increment so that the manipulator moves at a speed proportional to the displacement amount, and adding or subtracting this speed increment to the previous target coordinate. target coordinate updating means for newly updating the target coordinates; deviation calculating means for calculating a deviation from the target coordinates updated by the target coordinate updating means and the current coordinates of the manipulator; In order to generate an appropriate thrust without damaging the controlled object and the manipulator, the thrust is output while the update of new target coordinates in the same direction is stopped while the deviation limit value set in advance is exceeded. A method for controlling a servo manipulator, characterized in that control is performed by a deviation control means and a drive means for moving the manipulator to the target coordinates. 2. A method for controlling a servo manipulator according to claim 1, wherein the deviation limit value is a D/A converter output limit value for the actuator of each axis of the manipulator. 3. In claim 1, the deviation control means moves while generating preset vibrations in one or more directions perpendicular to the direction of propulsion of the thrust of the shaft that exceeds the deviation limit value. How to control the servo manipulator. 4. In claim 1, the conveyor movement amount detected by a position detection means for detecting the movement amount of the conveyor attached to the drive actuator of the conveyor on which the manipulator moves is set to the target coordinates of the manipulator in the same direction as the conveyor. A method for controlling a servo manipulator, which is a manipulator that has a target coordinate updating means that adds or subtracts from the target coordinates.