JPH02280684A - Speed controller - Google Patents

Abstract

PURPOSE:To smooth the acceleration and deceleration of a driven body by a method wherein an acceleration and/or deceleration starting command is inputted to control the speed of the driven body so that the changing rate of the acceleration of the driven body becomes constant upon starting and finishing the acceleration and/or deceleration of the driven body. CONSTITUTION:A speed command from a speed commanding means 22 is outputted to a driving means 10 and the driving means 10 drives a driven body based on the speed command. Accordingly, acceleration is started smoothly upon starting the acceleration while the acceleration is finished smoothly upon finishing the acceleration. On the other hand, a deceleration starting position operating means 23 operates a deceleration starting position based on a difference between the objective position and the present position of the driven body and outputs a deceleration starting command to the speed commanding means 22 when the driven body has arrived at the deceleration starting position. The speed command outputting means 22 receives the deceleration starting command and outputs a speed command so that the changing rate of the deceleration becomes constant upon starting the deceleration. When the deceleration has arrived at the finish of the same, the speed command is outputted so that the changing rate of the acceleration becomes constant again.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention enables smooth acceleration and deceleration of a driven body, and also automatically calculates the deceleration position when decelerating. The present invention relates to a speed control device that can control speed.

(Prior Art) In recent years, various robots have been used in industry to process and assemble products.

When production is performed using robots in this way, the production efficiency depends on many factors on the production speed of the robot. Specifically, the production efficiency is determined depending on the moving speed of the robot component H.

Therefore, conventionally, in order to obtain a certain degree of speed within a range in which positioning accuracy is maintained, for example, as shown in FIG. 7A, when accelerating or decelerating the component, the As shown in Figure 7B, this is performed based on an acceleration command that changes in a rectangular waveform.

Note that this acceleration command is stored in advance in a memory, and is taken out from this memory in accordance with the movement position of the component.

However, when a rectangular wave acceleration command is output in this way, the acceleration suddenly changes from the zero state to the acceleration value retrieved from the memory, or vice versa, so the speed of the component changes suddenly, and this speed The sudden change in H will apply a mechanical shock to the component, but will not adversely affect the mechanical life of the component H.

Therefore, recently, in order to eliminate the above-mentioned problems, a pattern of acceleration and deceleration is stored in a memory so that the speed changes in a bell shape as shown in Fig. There is a technique that extracts the acceleration value at that position from memory and smoothes the speed change at the start and end of acceleration/deceleration.

(Problem to be Solved by the Invention) However, even with a speed control device designed to smooth speed changes at the start and end of acceleration/deceleration, it is difficult to achieve the bell-shaped speed pattern described above. To get
There is a problem in that not only is it necessary to store in advance acceleration values corresponding to the movement positions of each component part of the robot, but also the storage capacity becomes extremely large.

The present invention has been made in view of such conventional problems, and it is possible to smoothly accelerate or decelerate a driven body without preparing data regarding acceleration and deceleration of the driven body in advance. It is an object of the present invention to provide a speed control device that can automatically calculate a deceleration position when decelerating.

(Means for Solving the Problems) The present invention to achieve the above-mentioned object is to input an acceleration/deceleration start command to a speed control device that controls the speed of a driven body, and to start acceleration/deceleration of the driven body. While outputting a speed command such that the rate of change in acceleration is constant at the time and end of the process, during the acceleration/deceleration period where steady acceleration/deceleration is performed, the speed is set based on the acceleration set at r. a speed command output means for outputting a command; and a deceleration start position calculation means for calculating a deceleration start position based on the difference between the Ut=position of the driven body and the current position, and outputting a deceleration start command to the speed command output means. and a drive means for driving the driven body in accordance with a speed command output from the speed command means.

(Function) When an acceleration start command is output from the outside, the speed command means outputs a speed command such that the rate of change in acceleration (+) is constant at the start of acceleration, and the speed command is accelerated to a certain degree and becomes a steady acceleration. In the area where acceleration is performed, a speed command is output based on a preset constant acceleration, and when the acceleration progresses further and reaches the end of acceleration, the rate of change of acceleration (
-) outputs a speed command that is constant. The speed command output from the speed command means is output to the driving means, and the driving means drives the moving object based on this speed command. Therefore, acceleration starts smoothly at the start of acceleration, accelerates at a constant acceleration during steady state, and ends smoothly at the end of acceleration.

On the other hand, the deceleration start position calculation means calculates the deceleration start position based on the difference between the target position and the current position of the driven body, and when the deceleration start position is reached, outputs a deceleration start command to the speed command output means. In response to this deceleration start command, the speed command output means outputs a speed command such that the rate of change (-) in acceleration is constant at the start of deceleration, and within a region where steady acceleration is performed after deceleration to a certain degree. Now, output a speed command based on a preset constant acceleration,
When the deceleration progresses further and reaches the end of the deceleration, a speed command is outputted again so that the rate of change (+) of the acceleration becomes constant.

(Example) Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a schematic configuration diagram of a speed control device according to the present invention. As shown in the figure, an arm of a robot (not shown), which is a driven object, is driven by a motor 10. This motor 10 includes an encoder (hereinafter referred to as IEN) 11 that outputs a pulse signal for each unit of rotation 1 (+), and a tachogenerator (hereinafter referred to as IEN) 11 that outputs a voltage according to its rotation speed.
Hereinafter referred to as TG. ) 12 are built-in. Further, the motor 10 is connected to a drive amplifier 20, and the rotation speed is controlled by the drive amplifier 20. And L:Nl
An encoding circuit 13 for encoding the pulse signal output from N11, that is, a position feedback signal, is connected to l, and the encoded signal is connected to a current position counter 14 for calculating the current position, and a current position counter 14 for calculating the current position. It is output to the movement amount counter 15 for calculating the amount.

The movement amount counter 15 is a D/A converter 1 that converts the number of pulses stored in the counter 15 into an analog amount.
6, and this analog quantity is output as a speed signal to the switching circuit 18 via the route switch 17. A final speed storage section 19 in which the final speed of the driven body is set is connected to this switching circuit 18.
The speed signal output from the route switch 17 by
A selection is made between the signal and the signal related to the final speed stored in the final speed storage section 19. Then, the speed signal selected by the switching circuit 18 is output to the amplifier 21,
The amplified signal here is output to the drive amplifier 20.

The speed feedback signal i from the 'l'' G12 is input to the drive amplifier 20, and speed feedback control is performed.The speed command section 22 is connected to the D/A converter 16 and the microcomputer 23. , movement counter 1
A speed switching command is output to the switching circuit 18 based on the movement amount outputted from the switching circuit 18. Incidentally, a current location counter 14 and a movement amount counter 15 are connected to the microcomputer 23, so that the values in these counters can be controlled by the microcomputer 23 and can be detected.

The speed controller configured as described above operates as follows. This operation is shown below in Figure 2A.
This will be explained with reference to the flowcharts of FIGS. 2B and 3 and FIGS. 4A to 6.

FIG. 2A is the main flowchart. First, the program starts and V is set as the target speed in the microcomputer 23. is set (Sl), the microcomputer 23 calculates the acceleration, and the speed command unit 22
outputs the signal that the acceleration is maintained (82
．． S3). The microcomputer 23 controls the speed command unit 2
Feedback signal from 2 or current location counter 1
4. The current speed is calculated based on the count value of the movement amount counter 15, and the speed is ■. If the speed has reached V, the above processing is finished, and the speed is V. If it has not reached S2, the process returns to S2. The processing speed of S3 is V.

This process is repeated until reaching (S4).

FIG. 2B is a subroutine flowchart of the step of calculating acceleration in the main flowchart described above,
The following processing is performed.

First, the first acceleration a1 is calculated by adding jerk aa, which is a differential value of acceleration, to the current acceleration a0. This jerk aa is a predetermined constant value. Therefore, acceleration a1 is calculated by adding jerk to the current acceleration at predetermined time intervals; at the beginning of acceleration, the acceleration is aa, then after a certain period of time it becomes 2aa, and then after a certain period of time has elapsed, Later it will be 3aa. In this way, the acceleration increases by aa every time a predetermined period of time elapses. If this state is shown in a diagram, the acceleration a1 becomes like a straight line a1 in FIG. 5 (SlO). Next, the second acceleration a2 is set to the maximum acceleration a0. This acceleration a
2 is unrelated to time, so it becomes like the straight line a2 in FIG. 5 (S11). Next, the third acceleration is calculated by multiplying the square root of the difference between the target speed and the current speed by a constant K.

This calculation formula was obtained by transforming the calculation formula used in 810, but the purpose of calculating with this formula is to prevent the value obtained by this formula from being used as the acceleration during acceleration. This is because it is necessary to do so. The state of change in this acceleration is illustrated as a straight line shown at a3 in FIG. 5 (S12). Then, from each acceleration obtained from SIO by 312,
The smallest acceleration is selected and this acceleration is set as the acceleration a shown in S2 (31 B). Therefore,
At the initial stage of acceleration, the acceleration calculated in S10 is adopted,
Acceleration is performed at a preset rate of change in jerk aa at predetermined intervals, and when acceleration continues to a certain point, S
The acceleration calculated in S12 is used to perform acceleration at a constant acceleration, and when the end of acceleration approaches, the acceleration calculated in S12 is used.

The following I- is for acceleration, but the same is true for deceleration (, l; in this case, the value obtained by adding a minus to the calculated acceleration is set as the acceleration during deceleration.

By performing speed control as described in 1- above, acceleration or deceleration can be performed with smooth speed changes as shown in FIG. 4A. When such speed control is performed, the acceleration changes in a trapezoidal shape as shown in FIG. 4B.

FIG. 3 is a flowchart for calculating the deceleration point, and the microcomputer 23 calculates the current speed V by multiplying the square root of the difference between the target position and the current position by a constant K.
20) If this current speed is larger than the predetermined maximum speed, set the target speed to the maximum speed 821
．． 22) If the current speed is below the maximum speed, set the target speed to 0 and output a deceleration command (821.23).

In this way, the microcomputer 23 calculates the target speed shown by the straight line (■) in FIG. 6 from the relationship between the target position and the current position, and automatically calculates the A signal to set the target speed to 0, that is, a deceleration command, is output at 5'', and deceleration is started by outputting this signal at 5''.

In the embodiments described below, the speed control of a robot has been described as an example, but the present invention is not limited to this, and can be applied to speed control when moving a driven object from any point to any point. Of course, it can be applied to anything.

(Effect of the invention) As is clear from the explanation in 1- below, according to the present invention,
To enable smooth acceleration/deceleration of a driven object and to automatically calculate the deceleration position when decelerating, without having to process or prepare data related to the acceleration/deceleration of the driven object. will be possible.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram of the speed control device of the present invention, and FIG.
2B and 3 are operation flowcharts of the speed control device of the present invention, and FIGS. 4A and 4B are diagrams showing an example of speed control by the speed control device of the present invention and the state of change in acceleration thereof. , FIG. 5 and FIG. 6 are diagrams showing the calculation state of acceleration and deceleration point in the speed control device of the present invention, and FIG. 7A and FIG. 7B are diagrams showing an example of speed control by the conventional speed control device and FIG. 8, which is a diagram showing how the acceleration changes, is a diagram showing an example of speed control by another conventional speed control device. 2nd AII 2nd al1 0... Motor (driving means), 0... Drive amplifier (driving means), 2... Speed command section (speed command output means), 3... Microcomputer (speed command output means) , deceleration start position calculation means).

Claims (1)

[Claims] In a speed control device that controls the speed of a driven object,
An acceleration/deceleration start command is input, and a speed command is output such that the rate of change in acceleration is constant at the start and end of acceleration/deceleration of the driven body, while the acceleration/deceleration is performed at a steady rate. During deceleration, a speed command output means outputs a speed command based on a preset acceleration, and a deceleration start position is calculated based on the difference between the target position and the current position of the driven body, and the speed command is A speed control device comprising: a deceleration start position calculation means for outputting a deceleration start command to an output means; and a drive means for driving the driven body in accordance with the speed command output from the speed command means.