JPH11149304A - Controller for industrial robot - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily avoid segment over, which can occur near a unique point etc., with the shift of an orthogonal increment at the time of a manual operation with a unified method in the control of a robot. SOLUTION: A controller is provided with an orthogonal increment addition part 12 adding an orthogonal increment 11 which is manually inputted to the present orthogonal position of a robot and updating the orthogonal present value, an inverse conversion part 3 converting the updated orthogonal present value into the positions of respective robot shafts, a segment data preparation part 14 preparing operation command data from a difference between the converted position and a target value before the orthogonal increment is added, a correction value operation part 15 selecting the minimum value of the calculated correction values for every shafts on the shaft where operation command data exceed a permitted maximum speed after the operation command data on the respective shafts are prepared, a correction value multiplication part 16 making a value obtained by multiplying operation command data of the whole shafts by the minimum value of the selected correction value new operation command data, an operation command data command part 17 outputting the operation command data to a servo driving system 18 and an order conversion part 19 making the orthogonal position operated based on new operation command data the orthogonal present value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an industrial robot, and more particularly to a control device for an industrial robot which can pass a singular point when moving an orthogonal incremental value in a manual operation. Related to the control device.

[0002]

2. Description of the Related Art In many articulated robots, each joint is constituted by a rotating mechanism. In this case, as shown in FIG. 2, controlling the operation to the predetermined position with the predetermined orthogonal increment value only by the rotation of each joint angle, including the posture, is performed. That is,
A predetermined orthogonal increment value 21 is given, and an increment value addition operation unit 2
In step 2, the orthogonal increment value is added to the current value of the rectangular coordinate system, the target position and posture are calculated, and the inverse transform unit 23 converts the target position and posture in the rectangular coordinate system into the joint coordinate system ( The operation command data creation command unit 24 creates a difference (operation command data (also referred to as segment data)) from the joint coordinate data with respect to the target position before the addition of the orthogonal increment value. By output, the operation of the quadrature increment value at the time of manual operation is realized. By the way, it is known that a multi-degree-of-freedom articulated robot has a plurality of solutions at the time of inverse transformation. In the case of performing the orthogonal increment value movement, if a solution is appropriately selected and operated, the singular point and the vicinity thereof may be passed on the way, and when the interpolation operation is performed at the specified operation speed, it becomes as shown in FIG. As shown in the figure, there is a case where the joint speed of each axis exceeds the allowable maximum speed and becomes inoperable (referred to as segment over). As a means for solving this, conventionally, a device that detects the vicinity of a singular point and switches an arithmetic algorithm at and around the singular point to avoid the singular point has been avoided.

[0003]

However, in the conventional apparatus, an algorithm for detecting a singular point is changed, and special processing is required. In addition, whether or not each axis can be operated is difficult to reliably determine whether or not each axis can be operated because conditions vary depending on the operating speed and the position of the robot at that time. Furthermore, for example, as in the case where the arm performs an interpolation operation near the coordinate origin, the joint speed of each axis may also become inoperable beyond the permissible maximum speed in addition to the singular point. To avoid this, another algorithm is needed. An object of the present invention is to provide a robot control device capable of easily and unifiedly avoiding a segment over that may occur near a singular point or at another position due to the movement of the orthogonal increment value during manual operation. That is.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an industrial robot control device capable of moving an incremental value at the time of manual operation. Means for creating an orthogonal increment value based on the above, an orthogonal increment value adding unit for adding the orthogonal increment value to the current orthogonal position of the robot and updating the orthogonal current value, and an orthogonal value updated by the orthogonal value increment value adding unit. An inverse converter for converting the current value into the position of each axis of the robot; and operation command data created from a difference between the position of each axis of the robot converted by the inverse converter and the target value before the addition of the orthogonal increment value. After creating the operation command data for each axis,
For the axis whose operation command data exceeds the allowable maximum speed, calculate the correction value by dividing the allowable maximum speed by the operation command data,
A correction value calculation unit for selecting the minimum value of the calculated correction value for each axis, and a correction value multiplication that sets a value obtained by multiplying the operation command data of all axes by the selected minimum value of the correction value as new operation command data. Unit, an operation command data command unit that outputs operation command data to the servo drive system, and a forward conversion unit that calculates an orthogonal position based on new operation command data and uses the calculated orthogonal position as a current orthogonal value. It is characterized by having. Accordingly, when the operation command data in the movement of the orthogonal increment value exceeds the allowable maximum speed, the operation command data is multiplied by the correction value, so that the operation is performed within the allowable maximum speed.

[0005]

Embodiments of the present invention will be described below. FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention. In the figure, 10 is a program pendant, 11 is a quadrature increment value, 12 is a quadrature increment value adder, 13 is an inverse converter, 14 is an operation command data generator, 15 is a correction value calculator, 16 is a correction value multiplier, 17 is a correction value multiplier. Is an operation command data command unit, 18 is a servo drive system, and 19 is a forward conversion unit. In the present invention, a correction value calculation unit 15, a correction value multiplication unit 16, and a forward conversion unit 19 are newly added to the conventional control device of FIG. In this embodiment, when the incremental value movement is started, a predetermined orthogonal incremental value 11 is given from the program pendant 10 for operating the robot, and the incremental value adding operation unit 12 adds the orthogonal incremental value 11 to the current value of the orthogonal coordinate system. Then, a target position and orientation are calculated, an inverse transformation unit 13 performs inverse transformation to convert the target position and orientation in the orthogonal coordinate system into a joint coordinate system, and an operation command data creation unit 14 performs the orthogonal transformation. The motion command data is created by taking the difference between the joint position data and the target position before the increment value is added.

Next, the correction value calculating section 15 calculates a correction value obtained by dividing the allowable maximum speed by the operation command data for the axis whose operation command data exceeds the allowable maximum speed, and calculates the minimum of the calculated correction value for each axis. Select a value. In the correction value multiplication unit 16,
New operation command data is calculated by multiplying the operation command data of all axes by the correction value calculated and selected by the correction value calculation unit 15. Then, the operation command data output section 17 outputs the operation command data to the servo drive system. Finally,
The forward transform unit 19 adds the increment value, adds the operation command data obtained by the correction value multiplying unit 16 to the joint coordinate system position before the inverse transform, and converts the added joint coordinate system position into the orthogonal coordinate system. Perform forward conversion. This calculates the orthogonal position for the next increment value movement process.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As a specific example, a two-axis robot will be described as an example. The allowable maximum speed is set to 100, and the first axis of the operation command data obtained by the operation command data creating unit 14 is set to 120 and the second axis is set to 80. The correction value calculation unit 15 calculates a correction value A1 for the first axis whose operation command data exceeds the allowable maximum speed.
Is calculated. A1 = 100/120 = 0.833 For the second axis, the correction value A2 is set to 1 because the operation command data does not exceed the allowable maximum speed. As described above, the minimum value A of the two-axis correction value is 0.833. In the correction value multiplication unit 16, 1
A is multiplied by the operation command data of the axes 2 and 2 to obtain new operation command data S1 and S2. S1 = 120 × 0.833 = 100 S2 = 80 × 0.833 = 67, and S1 and S2 are output to the servo drive system 18.
FIG. 3A shows the operation of the robot according to the present invention, which has been calculated as described above. As can be seen from the figure, there is a case where the joint speed of each axis exceeds the allowable maximum speed and becomes inoperable in the related art as shown in B, but in the case of the present invention, the operation does not exceed the maximum joint speed. , It is possible to avoid inoperability due to segment over.

[0008]

As described above, according to the present invention, in order to prevent the operation command data based on the orthogonal increment value from exceeding the allowable maximum speed, not only the vicinity of the singular point but also the manual operation in the entire operation range. Inoperability due to segment over at the time of moving the increment value can be avoided. Further, there is no need for an algorithm for detecting a singular point or the like.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing a conventional example.

FIG. 3 is a time chart showing operations of a robot according to the present invention and a conventional example.

[Explanation of symbols]

10 Program pendant, 11 Orthogonal increment value, 12
Orthogonal incremental value adder, 13 inverse converter, 14 operation command data generator, 15 correction value calculator, 16 correction value multiplier, 17 operation command data commander, 18 servo drive system, 19 forward converter

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI G05B 19/407 Q

Claims (1)

[Claims] 1. An industrial robot control device capable of moving an incremental value during a manual operation, comprising: means for creating an orthogonal incremental value based on an operation request input manually during a manual operation; Is added to the current robot's orthogonal position,
A quadrature increment value adder for updating the quadrature current value; an inverse converter for converting the quadrature current value updated by the quadrature value increment value adder to the position of each axis of the robot; and a robot converted by the inverse converter. An operation command data creation unit that creates operation command data from the difference between the position of each axis and the target value before the addition of the orthogonal increment value, and after creating the operation command data for each axis, the operation command data exceeds the allowable maximum speed. A correction value obtained by dividing the allowable maximum speed by the operation command data for each of the axes, and selecting a minimum value of the calculated correction values for each axis; and calculating the minimum value of the selected correction values for all axes. A correction value multiplication unit that uses the value multiplied by the axis operation command data as new operation command data, an operation command data command unit that outputs operation command data to the servo drive system, and an orthogonal position based on the new operation command data And the operation Control device of an industrial robot, characterized in that a rectifier unit to orthogonal current values orthogonal positions.