JPS5858683B2 - speed command device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a speed command device used in a positioning servo system.

Generally, when positioning control is performed, a speed command is issued according to the distance between the target stop position of the controlled object and the current position, and the speed of the servo motor is sequentially decreased to control the controlled object to stop at a predetermined position.

Figure 1 is a time chart to explain the principle.
When stopping at the target stop position S starting from the current stop position A, from point A to point B is ■4, and from point B to point C is ■
3. From point C to point D, output the speed command value of ■2 and from point D to ■1 to reduce the speed of the servo motor in order, and at point 8, set the speed command to zero and move the controlled object to the corresponding position. It indicates to stop at S.

Conventionally, in this positioning control method, the difference (movement amount) between the current stop position and the target stop position is initially set in a counter, and then the counter is decremented by 1 every time the controlled object moves by a unit amount. A method is known in which a predetermined speed command value is read out from a storage device each time using the contents of a counter as address information, and this is converted into analog to obtain a speed command signal to perform speed control.

However, in the case of this conventional method, it is necessary to store the speed command value for each unit movement amount of the controlled object in the storage device.
The disadvantage is that the capacity of the storage device is very large.

The present invention has been made to eliminate the drawbacks of the prior art described above, and focuses on the fact that the speed command value decreases in stages as shown in Figure 1. The object of the present invention is to provide a speed command device for a positioning servo system that makes it possible to read out the same speed command value by accessing the same address in the storage device, thereby greatly reducing the capacity of the storage section. .

Hereinafter, the content of the present invention will be explained in detail with reference to Examples.

FIG. 2 is a block diagram of an embodiment of the speed command device according to the present invention.

In the figure, a movement amount/direction calculation circuit 1 calculates the movement amount from the difference between the current stop position information and the target stop position information given from the outside, and at the same time determines the movement direction of the controlled object based on the magnitude of the image information. It is something.

The movement amount counter 2 is initially set to the movement amount of the movement amount/direction calculation circuit 1, and is then decremented by 1 by a timing signal given from the servo system for each unit movement amount of the controlled object. The content represents the actual distance of the controlled object from the target stop position.

The comparison circuit 3 compares the contents of the movement amount counter 2 with the speed switching code read from the storage device 5, and determines +2. A +1 or -1 signal is given to the address counter.

The address counter 4 specifies the read address of the storage device 5, and its contents are determined by the output of the comparison circuit 3 from +2. +1
Or -1.

The storage device 5 has a speed switching code and a speed command value stored therein, and the address counter 4 reads out one of them, and gives the speed switching code to the comparison circuit 3.
The speed command value is given to the digital-to-analog converter 6.

When the digital-to-analog converter 6 converts the speed command value read from the storage device 5 into an analog signal,
The polarity of the analog signal is determined by the direction command given from the movement amount/direction calculation circuit 1, and is given to the servo system as an analog speed command value.

7 is a signal amplifier. Next, the operation shown in FIG. 2 will be explained with reference to the flowchart shown in FIG.

Here, it is assumed that the storage device 5 has the memory configuration shown in FIG.

At the start of the operation, the current stop position information and target stop position information of the controlled object are given to the movement amount/direction calculation circuit 1, so that the movement amount (referred to as A) and the movement direction of the controlled object are calculated, Movement amount A is movement amount counter 2
The direction of movement is given to the digital-to-analog converter 6 as a direction command.

At this time, the movement amount/direction calculation circuit 1 initializes the address counter 4 with address information indicating the MA2 address of the storage device 5.

This completes the preparation for operation, and first, the address counter 4 reads out the contents (referred to as M) of address MA2 in the storage device 5 (step 1).

From Figure 4, the content of MA2 address is "■ Switching code to 5"
The content M and the movement amount A of the movement amount counter 2 are compared in the comparison circuit 3 (step 2).

As a result of the comparison, if the amount of movement is smaller, the content of the address counter 4 (assumed to be MAC) becomes + due to the output of the comparison circuit 3.
2 (step 3), and the address counter 4 is MA4.
It is S to indicate the address.

The storage device 5 is accessed again based on the contents of the address counter 4, and the contents of address MA4 are read out.

The content of address MA4 is "switching code to ■4", and this is again compared with the movement amount of movement amount counter 2 in comparator circuit 3.

As a result, if the movement amount A is larger, the content MAC of the address counter 4 is decremented by 1 by the output of the comparison circuit 3 (step 4), and the "speed command value" stored at address MA3 of the storage device 5 is V5J is read (step 5).

This speed command value 5 is given to the digital/analog converter 6, converted into an analog speed signal, and output to the servo system (step 6).

At this time, the polarity of the analog speed signal is determined by the direction 1 command given from the movement amount/direction calculation circuit 1.

When the speed signal is output from the digital-to-analog converter 6, the controlled object starts moving, and a timing signal arrives from the servo system for each unit movement amount, and is applied to the movement amount counter 2 through the signal amplifier 7. Ru.

By applying this timing signal, the content A of the movement amount counter 2
is reduced to -1 (step 7.8).

The comparator circuit 3 determines whether the content A of the movement amount counter 2 that has been decremented by 1 is O, and if A=0, the address counter 4
The content MAC of is incremented by 1 (step 9.10).

As a result, the contents of the address counter 4 indicate the address MA4, and the "switching code to ■4" is read from the storage device 5 (step 11).

The output M of the storage device 5 is compared with the content A of the movement amount counter 2 in the comparison circuit 3 (step 12), and if M<A, the content MAC of the address counter 4 is decremented by 1 (step 4), and the storage device "Speed command value V5J" of MA3 address of 5
is read out again and applied to the digital-to-analog converter 6.

Thereafter, the content A of the movement amount counter 2 is sequentially decremented by 1 due to the arrival of the timing signal, and each time, on the condition that A=0, the content M of the address MA4 of the storage device 5, that is, "switching to ■4"code" is read out, and while M<A, M
The speed command value V5J at address A3 is repeatedly read out and given to the digital-to-analog converter 6.

Content A of movement amount counter 2 is decremented, and it becomes M
If it is smaller than the “■4 switching code” at address A4,
The content MA of the address counter 4 is determined by the output of the comparison circuit 3.
C is incremented by 1 (step 13), and the contents of address MA5 of the storage device 5 are read.

As shown in FIG. 4, the contents of address MA5 are "speed command value ■4", and this is given to the servo system through the digital-to-analog converter 6.

After that, as before, the content A of the movement amount counter 2 is sequentially decremented by 1 due to the arrival of the timing signal, and each time, A-0
Under the condition that MA6 of storage device 5 is not
The content M of the address, that is, the "switching code to ■3" is read out, and if M<A, the "speed command value ■4" at address MA5 is repeatedly read out and given to the digital-to-analog converter 6 during that period. It will be done.

Thereafter, until the content A of the movement amount counter 2 becomes 0, the fourth
According to the memory configuration shown in the figure, the speed command value is set to ■3. ■2. ■１
It switches.

In this way, when the content of the movement amount counter 2 becomes 0, reading out the speed command value from the storage device 5 is prohibited, that is, the speed command value becomes O, and a positioning signal is given to the servo system to move the controlled object. will stop at the target stop position (step 14).

Note that various methods of providing the positioning signal have been proposed in the past, and since they are not directly related to the present invention, detailed explanation thereof will be omitted.

The illustrated configuration is merely one example, and various other configurations are possible.

For example, in the embodiment, the address counter has both addition and subtraction functions, but if it only has one of the functions, the same operation can be achieved by using the address counter's save register. be.

Also, although we have shown the case where the speed command and speed switching code are arranged alternately in the storage device, it is possible to arrange these in separate blocks and use two address counters, or
Alternatively, an address counter and a save register may be used to access each.

As is clear from the above description, according to the present invention, the contents of the storage device only need to be speed commands and speed switching codes according to the type of speed, and the capacity of the storage device is significantly reduced compared to the conventional method.

This means that especially when a microprocessor system is used, it is equipped with an addition/subtraction function, an address counter, a determination function, a save register, etc., and together with the memory section, the device can be miniaturized.

[Brief explanation of the drawing]

Fig. 1 is a diagram explaining the principle of positioning control, Fig. 2 is a diagram showing an embodiment of the speed command device according to the present invention, Fig. 3 is a time chart for explaining the operation of Fig. 2, and Fig. 4 is a diagram illustrating the principle of positioning control. Second
FIG. 3 is a diagram showing an example of a memory configuration of the storage device shown in the figure. 1...Movement amount/direction calculation circuit, 2...
Movement amount counter, 3... Comparison circuit, 4...
...Address counter, 5...Storage device, 6.
...Digital-to-analog converter.

Claims (1)

[Claims] 1. In a positioning servo system speed command device that sequentially switches between multiple types of speed commands according to the distance between the current position of a controlled object and a target stop position, and controls the speed of the controlled object to stop it at a predetermined position, The contents are updated for each unit movement amount of the controlled object, and a movement amount counter indicating the distance between the current position and the target stop position of the controlled object, and the plurality of types of speed commands and speed switching codes are stored at each address. A storage unit stored in the storage unit and a speed switching code for switching to the next level speed command are read from the storage unit each time the movement amount counter is updated, and the contents of the read speed switching code and the movement amount counter are read out from the storage unit. a comparison control unit that determines whether to continue reading out the speed command at the current level or read out the speed command at the next level indicated by the speed switching code, thereby reading out the speed designation from the storage unit; A speed specifying device comprising: