JPH056686B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a drive control method for an articulated robot.

Background of the Technology Recently, articulated robots with multiple degrees of freedom have been used in various manufacturing industries. In this case, each joint (each axis) is moved and the position of the hand is determined by combining these movements.

Conventional technology and problems Conventionally, when there are no specific special requirements for the movement trajectory of the hand of such an articulated robot (for example, a request for movement in a straight line or in an arc), each It was driven by giving each joint its own speed. In such conventional methods, joints that move only a short distance end their movement earlier than the distance traveled by the hand to reach the target position, while axes that have to move a long distance end their movement that much more slowly. It will end.

Therefore, each joint moves differently,
The drawback was that it was impossible to predict how each joint would move relative to the target position of the hand because it could not be unified as a whole.

Purpose of the Invention The purpose of the present invention is to overcome the drawbacks of the conventional drive method described above, and to smoothly unify the movements of each joint to perform pseudo-trajectory control even when trajectory control is not required for the hands of an articulated robot. An object of the present invention is to provide an improved drive control method for an articulated robot.

Structure of the Invention In order to achieve this object, the present invention provides a multi-joint robot having multiple degrees of freedom by driving each joint with the target position of each joint when the hand of the multi-joint robot moves to a target position. In a drive control method for an articulated robot, the amount of movement of each joint is calculated based on the current position and target position of each joint, and the amount of movement is divided by the maximum movement speed of each joint. The movement time of each joint is determined by calculating the movement time of each joint, and the movement speed of other joints is corrected by dividing the movement distance of other joints by the maximum movement speed of the joint with the maximum movement time among the movement times determined. Then, using the corrected movement speed, each joint is moved according to the joint that takes the longest time so that when the hand reaches the target position, each joint reaches each target position at the same time, and the entire robot is moved. It is characterized by being driven.

Examples of the invention Hereinafter, the present invention will be specifically explained with reference to the drawings.

FIG. 1 is a block diagram showing the overall structure of the drive control method of the present invention.

That is, as shown in the figure, information on the current position is obtained from each joint 1, the calculation unit 2 calculates the moving distance and moving speed to the target position, and gives a drive command to each joint 1. At this time, since the target position of each joint is stored in the memory 3, the movement distance to the target position is obtained by subtracting the value of each joint at the current position from the value of each joint at the target position.

FIG. 2 is a conceptual diagram of an articulated robot having six degrees of freedom (six axes), which is an embodiment of the controlled object of the present invention.

In the figure, θ ₁ , θ ₄ and θ ₆ are rotating shafts (actuators), and θ ₂ , θ ₃ and θ ₅ are bending shafts (actuators). And H is the robot's minion.

FIG. 3 is a flowchart for explaining the drive control method of the present invention.

First, at A, the moving distances L ₁ to _{L 6} of each joint θ ₁ to _{θ 6} to the target position are calculated. The calculation method has already been described in the explanation of FIG.

Next, at B, the movement time T ₁ to _{T 6} of each joint θ ₁ to θ ₆
Calculate. This is determined by dividing the moving distance of each joint by the maximum moving speed determined for each joint. The maximum value among them is set as Tmax (C).

The maximum movement speed Vmax is determined by dividing the movement distance Lm of the joint related to Tmax, that is, the joint θm that takes the longest time, by Tmax (D).

Finally, each movement speed Vi is calculated by dividing the movement distance Li of the other joints θi by the maximum movement time Tmax (E).

By giving the movement speeds Vi and Vmax obtained in this way to each joint θi and θm, no matter where the target position of the hand H is, other joints can be moved according to the joint θn that takes the most time. Since θi follows and moves, the movement of each joint ends at the same time at the target position, and a smooth trajectory is obtained.

FIG. 4 is a side view of an articulated robot according to an embodiment for explaining the effects of the present invention.

As shown in the figure, the robot in this case is comprised of one rotating shaft 10 and one linear shaft (sliding shaft) 20. In addition, the linear axis 2
A hand H is provided at the tip of 0.

If you are currently at the position shown by the solid line and move to the target position shown by the broken line, conventionally the hand H would draw a turbulent trajectory as shown at 30.
According to the drive control method of the present invention, the hand H can draw a smooth trajectory as shown at 40.

Note that in the above embodiment, the amount of movement of the rotary shaft 10 is small and the amount of movement of the linear shaft 20 is large; however,
The present invention can be similarly applied to other cases.

Effects of the Invention As explained above, according to the present invention, the movement of the other joints is controlled in accordance with the movement of the joint that takes the most time, so that each joint reaches each target position at the same time. This makes it possible to smooth the trajectory of the robot's hands.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the overall configuration of the present invention, FIG. 2 is a conceptual diagram of an articulated robot according to an embodiment of the present invention, and FIG. 3 is a drive control flowchart of the robot shown in FIG. FIG. 4 is a side view of a robot according to an embodiment of the present invention. θ ₁ , θ ₄ , θ ₆ ... rotation type joint, θ ₂ , θ ₃ , θ ₅ ... bending type joint, 10 ... rotary axis, 20 ... linear axis, H
...Stooge, 30...Traditional hand trajectory, 40...
The trajectory of the hand according to the present invention.

Claims (1)

[Scope of Claims] 1. A multi-joint robot that controls the drive of a multi-joint robot having multiple degrees of freedom by driving each joint with the position of each joint as a target when the hand of the multi-joint robot moves to a target position. In a drive control method for a type robot, the amount of movement of each joint is calculated based on the current position and target position of each joint, and the amount of movement is divided by the maximum movement speed of each joint to calculate the movement time of each joint. Calculate the movement speed of the other joints by dividing the movement distance of the other joints by the maximum movement speed of the joint during the maximum movement time among the movement times determined, and correct the movement speed of the other joints, and calculate the corrected movement speed. is used to drive the entire robot by moving each joint according to the joint that takes the longest time so that when the hand reaches the target position, each joint reaches the target position at the same time. Drive control method for articulated robot.