JPH0315908A - Acceleration/deceleration method for locus direction of moving member - Google Patents

Abstract

PURPOSE:To attain a smooth movement without stopping a locus when a moving member changes in an orthogonal movement and a joint movement by independently accelerating and decelerating the orthogonal movement and the joint movement and respectively adding them. CONSTITUTION:An instruction is read from RAM. When it is a moving instruction, a moving quantity at that time is calculated and the data is transferred to an interpola tion processing. The moving quantity in unit time is obtained in the interpolation processing, and it is recognized whether a moving instruction is the orthogonal move ment or the joint movement. Then, orthogonal components and joint components are processed by different algorithms. When a new movement is the orthogonal move ment in the movement different from the present movement, namely, the present joint movement, the processing of a deceleration quantity is executed. When it is the orthogonal components, a system changes to the joint movement after the accelera tion processing. Next, both results are added and the result is outputted to the driving part of a joint axis as a servo command. Thus, smooth movement can continuously be executed without permitting the moving member to stop between two kinds of operations of the orthogonal movement and the joint movement.

Description

Detailed Description of the Invention [Industrial Field of Application] The present invention relates to acceleration/deceleration in the trajectory direction of a robot such as an articulated robot in which the motion of the point of action, which is the tip of the tip member, is orthogonal movement and joint movement. It is about the method.

[Conventional technology]

Conventionally, (1) all movements of movable members are converted into joint movements and acceleration/deceleration is performed for each joint, or (2) orthogonal movements are orthogonal, and joint movements are accelerated/decelerated at each joint using separate algorithms. was doing.

[Problem to be solved by the invention]

In the case of the above conventional technique (1), since the joint acceleration/deceleration control is performed, control cannot be performed according to the trajectory.

In the case of (2), there is a problem that the movable member stops once between the orthogonal movement control and the joint movement control, and the movements do not continue smoothly.

In a machine such as an articulated robot whose axes do not operate in a Cartesian coordinate system, if each axis is accelerated or decelerated, the trajectory will be complicated in the Cartesian coordinate system even if the acceleration/deceleration time constants of each axis are made to match. It becomes a curve. For this reason, in operations in the orthogonal coordinate system (linear movement, circular arc movement), it is necessary to accelerate and decelerate in the trajectory direction in the orthogonal coordinate system. On the other hand, in order to change the posture, etc., each axis may be operated separately, and in this case, acceleration and deceleration are performed for each axis.

It is an object of the present invention to provide a method for accelerating and decelerating a robot in the trajectory direction, which allows the above two types of operations to be performed continuously and smoothly without stopping between these operations.

[Means to solve the problem]

In order to achieve the above object, a method for accelerating/decelerating a movable member such as a robot in a trajectory direction according to the present invention is a method for accelerating/decelerating a movable member in a trajectory direction in which the motion of a point of action is orthogonal movement and joint movement. and acceleration/deceleration of joint movement separately, and then add them together.

In addition, in the method for accelerating and decelerating the moving member in the trajectory direction, if the movement command changes from orthogonal movement to joint movement while the moving member is moving, the amount of deceleration movement in the orthogonal direction is converted to the amount of joint movement, and this is used for the next joint movement. In addition to movement, if the movement command changes from joint movement to orthogonal movement, the amount of rapid movement of the joint axis can be converted into an orthogonal movement amount, and this can be added to the next orthogonal movement.

[For production]

In the above method, the trajectory of the moving member when the orthogonal movement and the joint movement mutually change is smoothly moved without stopping.

〔Example〕

Embodiments of the present invention will be described based on the drawings.

FIG. 1 shows a first embodiment of the present invention, which shows an algorithm for performing acceleration and deceleration of orthogonal movement and joint movement separately in parallel processing, and controlling them by adding them together.
Read a command from M, and if this is a movement command,
The amount of movement at this time is calculated and this data is passed to an interpolation process that starts at regular intervals.

After determining the amount of movement per unit time by interpolation processing, it is recognized whether the movement command is orthogonal movement or joint movement, and the orthogonal segment and joint components are processed using separate algorithms. At this time, if the movement is different from the current movement, for example, if the current joint movement is an orthogonal movement, then the deceleration amount is processed. In the case of orthogonal components, the motion is converted into joint movement after the acceleration/deceleration processing described above.

Then, the results of both processes are added and the result is output as a servo command to the joint axis drive unit.

Each signal in the above processing is as shown in Fig. 3, in which a and b are the orthogonal components and joint components after interpolation shown in Fig. 1, and c and d are the signals after the acceleration/deceleration processing. Each component, e, is a servo command signal after addition processing. Also, 11 in the figure is the interpolation step! I2 is the step of the instruction.

In addition, P1 + P2 * P in this figure 3
3 indicates the locus position of the tip member 2 of the four-axis articulated robot 1 at each step as shown in FIG.

FIG. 12 shows a second embodiment of the present invention, which shows a processing method for orthogonal single joint movement amount conversion when a movement command changes.
In this block diagram, the method up to reading instructions from the RAM, calculation of movement amount, and interpolation is the same as the method shown in FIG. 1 above.

Checks whether the movement command has changed after interpolation, and if the movement command changes from orthogonal movement to joint movement,
At A, change the orthogonal deceleration amount to the joint movement amount.

Further, when the movement command changes from joint movement to orthogonal movement, the deceleration amount of the joint is changed to the orthogonal movement amount at B.

Next, at C, each converted movement amount and new movement amount are added, and then acceleration/deceleration is performed, and if the result is orthogonal, it is output to the joint axis drive unit as a servo command instead of the joint.

The amount of deceleration of the orthogonal and joints described above is the remainder of the acceleration.

In the above case, when an FIR type filter is used for acceleration/deceleration of D, orthogonal movement is calculated as shown in FIG. 5, and Xn' is output.

When the next interpolation step is joint movement, calculations are performed as shown in FIG. 6, and θn' is output.

Also, the calculation of one joint axis in part A is θ1an-1
−f1 (Xn, Yn, Zn, an) θ 1 ar
r 2 −f'1 (Xn-1 +Yn-1
, Zn-t. a n-j ) θ+ an-
r)-f 1 (Xn-r+1 , Yn-r+1
．． Zn-r+1. αn-r+1) Similarly, for other axes, for example, θ2 an-1-f2 (Xn, Yn, Zn, α
n) etc.

Also, in part B, the joint movement orthogonal movement is calculated in the opposite way, but this is also calculated as X, -gt(θ1n, θ2n, θ3 n,
θ4n), etc.

In the above equation, x, y, z, α, and θ represent the amount of movement of the tip member 2 of the articulated robot 1 shown in FIG. 4 in each direction for each step.

FIG. 7 shows a servo mechanism that drives the driving parts of each joint of the 4-axis articulated robot shown in FIG. 4, in which 3 is an accumulator, 4 is a subtracter, 5 is an amplifier, and 6 is a motor, and 7 is a position sensor.

〔Effect of the invention〕

According to the present invention, two types of movements, orthogonal movement and joint movement, can be performed continuously and smoothly without stopping between these movements.

[Brief explanation of drawings]

The drawings show embodiments of the present invention; FIGS. 1 and 2 are block diagrams showing different methods, FIG. 3 is a diagram showing processed signals in the method shown in FIG. 1, and FIG. 4 is a diagram showing processed signals in the method shown in FIG. FIGS. 5 and 6 are explanatory diagrams showing an example of an articulated robot. FIGS. 5 and 6 are explanatory diagrams showing calculation examples of the method shown in FIG. 2. FIG. 7 is a block diagram showing drive control of the joint axis drive unit. be. 1 is an articulated robot, and 2 is a moving member. Figure 1 Figure 4 Figure 5 Figure 6

Claims (2)

[Claims] (1) A method for accelerating and decelerating a moving member in the trajectory direction in which the motion of the point of action is orthogonal movement and joint movement, characterized in that the acceleration and deceleration of orthogonal movement and joint movement are performed separately, and the acceleration and deceleration of orthogonal movement and joint movement are added. Acceleration/deceleration method in the trajectory direction. (2) In an acceleration/deceleration method in the trajectory direction of a moving member in which the motion of the point of action is orthogonal movement and joint movement, if the movement command changes from orthogonal movement to joint movement while the moving member is moving, the amount of deceleration movement in the orthogonal direction is converted into a joint movement amount, and this is added to the next joint movement. Also, if the above movement command changes from joint movement to orthogonal movement, convert the joint axis deceleration movement amount to orthogonal movement amount, and add this to the next joint movement. A method for accelerating and decelerating a moving member in a trajectory direction, characterized by adding the acceleration and deceleration to orthogonal movement.