JPH04352013A - Control device for robot - Google Patents

Abstract

PURPOSE:To shorten the tact time of a vertical joint type robot by displaying the moving operation capacity of the robot at its maximum in accordance with a load state. CONSTITUTION:Horizontal face distances between a base point and the moving start points of respective spindles or their moving end points or the coordinates of the moving start and end points of respective spindles are computed by the 1st to 3rd spindle acceleration/deceleration command means 22A to 22D, acceleration and deceleration corresponding to the distances or coordinates are read out from a load information table 21, and respective minimum values out of the read contents are selected by an acceleration/deceleration determining means 25 and applied as acceleration and deceleration command values to move respective spindles.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to a device for controlling the movement of each axis of a vertically articulated robot.

0002

[Prior Art] FIGS. 6 to 8 are, for example, Japanese Patent Laid-Open No. 1-295
FIG. 6 is a perspective view of a vertically articulated robot, FIG. 7 is a control block diagram, and FIG. 8 is a speed command value curve diagram.

In FIG. 6, reference numerals 1 to 6 indicate drive axes of the robot, which will hereinafter be referred to as J1 axes to J6 axes, respectively. 7 is a rotating base of the robot. In other words, J1 axis 1
is an axis for rotating the robot body on the swivel table 7, and J
The 2-axis 2 and the J3-axis 3 are axes that allow the arm of the robot to move back and forth and up and down, respectively, along a vertical plane. Also, J
The 4th axis 4 to the J6 axis 6 are wrist axes.

In FIG. 7, numeral 11 is a program memory in which a program and position data for the robot user to make the robot perform a desired task is stored, and numeral 12 is a program memory that is closed each time execution of a movement command in the program is started. accomplished,
A switch that opens when the movement target position is stored in the buffer 13; 14 is a buffer in which the current position of the robot is stored; 15A and 15B are buffers in which acceleration and deceleration are respectively stored; 16 is a switch allowed by the robot. Buffer where the maximum operating speed is stored, 17 is buffer 1
Speed command means for determining the speed at each point in time during the movement operation based on the target position, current position, acceleration, deceleration, and allowable maximum speed of 3 to 16; 18 adds the position indicated by the speed command value and the current position; The adder 19 is a buffer into which the speed command value is written.

A conventional robot control device is configured as described above, and when execution of a robot program is started, the switch 12 is closed each time a movement command is executed, and the movement target position is determined from the program memory 11. position buffer 1
3. When the target position is stored in the buffer 13, the switch 12 is opened. The speed command means 17 controls the speed so as not to exceed the allowable maximum speed of the buffer 16 based on the speed at the previous time, the acceleration and deceleration of the buffers 15A and 15B, and the target and current positions of the buffers 13 and 14 at each time point. A speed command value is calculated and written into the buffer 19, and at the same time, the adder 18 updates the current position.

At this time, as shown in FIG. 8, during acceleration T1 until reaching the maximum speed Vm during movement, the buffer 15A is
During the deceleration time T2 from the maximum speed Vm until reaching the target position, the deceleration of the buffer 15B is used to control the speed up to the target position.

[0007] The acceleration and deceleration used in the movement operation are specified in advance to be constant values and are the same for each movement, and the speeds are controlled so that the movement movement of each axis is completed at the same time. Here, in the case of a moving operation, the load conditions applied to the robot vary depending on the operating posture, the shape of the work to be handled, the weight, etc. Therefore, the acceleration and deceleration are determined so that the robot can operate without any trouble even when the maximum load is applied to the robot.

[0008]

[Problems to be Solved by the Invention] In the conventional robot control device as described above, the acceleration and deceleration during movement are determined based on the maximum load. There are problems in that robots are unable to perform their tasks at times, and robots are unable to complete their tasks within the desired time.

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a robot control device that can complete work within a targeted time depending on the load state. .

0010

[Means for Solving the Problems] A robot control device according to the present invention calculates the horizontal plane distance between a base point and the movement start point and movement end point of each axis or the coordinates of the movement start point, and calculates the adjustment corresponding to the distance or coordinates. The speeds are read out, the smallest one is selected from these, and these are used as the acceleration command value and deceleration command value.

[0011]

[Operation] In this invention, the acceleration/deceleration is read from the positions of the movement start point and the movement end point, and the minimum one is selected from these as the acceleration command value and deceleration command value. Acceleration and deceleration can be determined together.

0012

[Embodiment] Figures 1 to 5 are diagrams showing one embodiment of the present invention, in which Figure 1 is a control block diagram, Figure 2 is a content diagram of a load information table, and Figure 3 is an explanatory diagram of horizontal plane distance of a vertically articulated robot. ,
FIG. 4 is a flowchart showing the operation, and FIG. 5 is an explanatory diagram of the movement start point and movement end point, and the same parts as in the conventional device are designated by the same reference numerals.

In FIG. 1, reference numeral 21 indicates a load information table in which acceleration/deceleration information is written corresponding to the travel distance and coordinates as shown in FIG. 2, and 22A to 22D read load information from the load information table 21 and calculate acceleration First-axis (X-axis) acceleration/deceleration command means, second-axis (Y-axis) acceleration/deceleration command means, third-axis (Z-axis) acceleration/deceleration command means, and wrist-axis acceleration/deceleration that determine command values and deceleration command values. Command means, 23
A to 23D are acceleration/deceleration command means 22A to 22, respectively.
Buffer for storing acceleration determined by D, 24A
24D is a buffer for storing deceleration, 25 is acceleration/deceleration determining means for determining the optimum acceleration and deceleration from among the accelerations and decelerations stored in buffers 23A to 23D and 24A to 24D, and 26A and 26B are This is a switch that closes at the start of a moving operation and opens when the determined acceleration and deceleration are written into the buffers 15A and 15B.

In FIG. 2, Ro...Ri...Rn
As shown in Figure 3, at any position of the robot,
Distance R on the horizontal plane from the swivel base 7 to the tip of the J6 axis 6,
αo...αi...αn is the acceleration and deceleration of J1 axis 1 corresponding to each distance R, (J2)o...(J
2) i...(J2)m is the coordinate of J2 axis 2, βo...
βi...βn is the acceleration and deceleration of J2 axis 2 corresponding to the J2 axis coordinate, (J3)o...(J3)i...(J
3) l is the coordinate of the J3 axis 3, and γo...γi...γl are the acceleration and deceleration of the J3 axis 3 corresponding to the J3 axis coordinate.

Next, the operation of this embodiment will be described with reference to FIG. 2 regarding the movement from the movement start point 30 to the movement end point 31 shown in FIG. 5.

In FIG. 5, the coordinates of the X-axis to Z-axis at the movement start point 30 are Xs-Zs, the coordinates of the J1-axis 1 to J6-axis 6 are J1s-J6s, and the coordinates of the X-axis to Z-axis at the movement end point 31 are Xe. ~Ze, the coordinates of J1 axis 1 to J6 axis 6 are J1e
~ J6e. Moreover, the distance R in the horizontal plane from the swivel base 7 to the tip of the sixth shaft 6 at the movement start point 30 and the movement end point 31 are respectively written as Rs and Re. At this time, the distance Rs,
Re is given by the following formula.

[0017]

[Math 1]

First, in step 41, the first axis acceleration/deceleration command means 22A determines the movement start point 30 from the current position of the buffer 14 before starting the movement, and in step 42, the first axis acceleration/deceleration command means 22A determines the movement start point 30 from the current position of the buffer 14.
The movement end point 31 is determined from the target position. Then, in step 43, distances Rs and Re are calculated using the above equations. Next, in step 44, the load information table 21 is searched,
The acceleration and deceleration corresponding to the distance Rs are calculated as the acceleration of the J1 axis 1 in the main movement, and are written into the buffer 23A. In step 45, the deceleration corresponding to the distance Re is similarly calculated and written to the buffer 24A. Here, the values of the buffers 23A and 24A are candidates for the acceleration command value and deceleration command value.

The second axis acceleration/deceleration command means 22B also operates in the same manner as the first axis acceleration/deceleration command means 22A, but the acceleration/deceleration is determined by the coordinate value of the J2 axis 2 instead of the distance R. First, the coordinate J2s of the J2 axis 2 from the current position at the start of the movement to the movement start point 30, and the J2 axis 2 from the target position to the movement end point 31.
The coordinate J2e of is calculated. Next, load information table 2
1, and calculate the acceleration/deceleration corresponding to the coordinate J2s as the acceleration/deceleration of the J2 axis 2 in this movement,
The acceleration/deceleration corresponding to the coordinate J2e is calculated as the deceleration in the main movement, and is written into the buffers 23B and 24B, respectively.

The third axis acceleration/deceleration command means 22C operates in the same manner as the second axis acceleration/deceleration command means 22B, and calculates the acceleration and deceleration of the J3 axis 3, respectively, and sends them to the buffer 2.
Write to 3C and 24C.

The wrist axis acceleration/deceleration command unit 22D writes the same acceleration and deceleration for each movement operation into the buffers 23D and 24D, respectively.

Next, the acceleration/deceleration determining means 25 selects the smallest one from among the acceleration command value candidates in the buffers 23A to 23D and the deceleration command value candidates in the buffers 24A to 24D as the acceleration command value and the deceleration command value candidate for the main movement. Deceleration command values are determined and written into buffers 15A and 15B, respectively. A speed command value is determined using the acceleration command value and deceleration command value thus determined, and the target position, current position, and allowable maximum speed of the buffers 13, 14, and 16, and is written into the buffer 19.

In the above embodiment, the vertically articulated robot shown in FIG. 3 was explained, but the robot is not limited to this.
It is also applicable to vertically articulated robots with other axis configurations, and similar effects can be achieved.

[0024]

As explained above, in this invention, the horizontal plane distance between the base point and the movement start point and movement end point of each axis or the coordinates of the movement start point and movement end point are calculated, and the acceleration and deceleration corresponding to the distance or coordinates are calculated. is read out, the smallest one is selected from these, and each axis is moved using this as the acceleration command value and deceleration command value, so the acceleration and deceleration can be determined according to the load condition of the robot. This has the effect of maximizing the ability of the robot in moving operations, allowing the robot to complete its work within a targeted time, and shortening the robot's takt time.

[Brief explanation of the drawing]

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

FIG. 2 is a content diagram of the load information table in FIG. 1;

FIG. 3 is a horizontal plane distance explanatory diagram of the vertically articulated robot controlled according to FIG. 1;

FIG. 4 is a flowchart showing the operation of FIG. 1;

FIG. 5 is an explanatory diagram of a movement start point and a movement end point in FIG. 4;

FIG. 6 is a perspective view of a conventional vertically articulated robot.

FIG. 7 is a control block diagram of FIG. 6.

FIG. 8 is a speed command value curve diagram of FIG. 7;

[Explanation of symbols]

1 to 6 J1 axis to J6 axis 13
Target position buffer 14
Current position buffer 17
Speed command means 19 Speed command buffer 21 Load information storage means (load information table) 22A to 22D 1st to 3rd axes and wrist axis acceleration/deceleration command means 23A to 23D Acceleration buffers 24A to 24D Deceleration buffer 25 Acceleration/deceleration determination means 30
Movement starting point 31
Movement end point 0 Base point

Claims (1)

[Claims] 1. A device in which each axis of a robot is moved by an acceleration command value and a deceleration command value, and the speed is controlled such that each axis completes its movement simultaneously during the movement operation of each axis. A load information storage means in which acceleration and deceleration with respect to the axis position are written, and a horizontal plane distance between the base point and the movement start point and movement end point of each of the axes, or coordinates of the movement start point and movement end point, are calculated and the load information storage means is stored. acceleration/deceleration command means for reading out the acceleration and deceleration corresponding to the distance or coordinates from the means, and selecting the smallest one from the read acceleration and deceleration and using it as the acceleration command value and the acceleration command value for the movement operation. 1. A robot control device comprising: acceleration/deceleration determining means for determining a deceleration command value.