JPS62271111A - Velocity controller - Google Patents

Abstract

PURPOSE:To faithfully follow up the change of velocity command and to control by actual velocity command value high in resolution by making sampling time short when there is variation in velocity command voltage and making sampling time long when there is no variation in velocity command voltage. CONSTITUTION:A microcomputer 5 reads count value of a counter 3 and calculates finite difference a from the preceding count value and calculates a velocity command value A by multiplying the finite difference an by an integer N. Further, a velocity command value B is calculated by summing up finite difference for the newest N times. Command values A, B are substituted in the expression, and examined whether this condition is satisfied or not. When the condition is not satisfied, it is judged that velocity command voltage is changed, and the velocity command value A is selected as a actual velocity command value. When the condition is satisfied, the velocity command value B is selected as an actual velocity command value.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a speed control device for controlling the speed of a motor of an industrial machine or a machine tool, and particularly relates to a speed control device for controlling the speed of a motor of an industrial machine or a machine tool. It is about improvement.

[Conventional technology]

FIG. 3 is a block diagram showing the schematic configuration of this type of conventional speed control device, which includes a speed setter (1) that adjusts a variable resistor and outputs a speed command voltage, and a speed setter (1) that adjusts a variable resistor to output a speed command voltage, and A voltage-frequency converter (hereinafter referred to as V/'
F converter) (2), a counter (8) that counts the converted pulses, and the counted value of this counter are taken in via the data bus (4), and the actual speed command value is calculated. It is equipped with a microcomputer (5) that performs speed calculations and speed compensation processing.

In this configuration, when a desired speed is set with the speed setter (1), an analog speed command voltage corresponding to the speed is applied to the V/F converter (2), where it is converted into a pulse frequency. The converted pulses are counted by a counter (8), and the counted value is taken into the microcomputer (5).

In the microcomputer (5), the processing section layer is the fourth
As shown in the flowchart in the figure, first, Step 7)
' In (101), the difference an between the current count value of the counter (8) and the previous count value is calculated at regular intervals, and in step (102), this difference an is multiplied by N (N is an integer of 2 or more). Then, in step (103), this actual speed command value A is used to perform speed calculation and speed compensation processing. In order to improve the resolution, many microcomputers (5) perform the processing shown in the flowchart of FIG. 5.

That is, in step (111), the difference an between the current count value and the previous count value of the counter (8) is calculated at fixed time intervals, and in step (112), the sum of the latest N differences B:' n+1-M ” 'n+2-N ””” an
is determined, and in step (113), this sum B is determined as the actual speed command value REF, and further, in step (N4), speed calculation and speed compensation processing are performed using the actual speed command value B.

[Problem that the invention seeks to solve]

The conventional speed control device is configured as described above, and even though the hardware is the same, speed calculation and speed compensation processing are performed based on two types of actual speed command values using different calculation methods.

However, if the latest difference in the counter (8) is multiplied by N to obtain the actual speed command A=NX, the result is an The actual speed command value B" an-1-1-N " aH+2-N+・
・When calculating +an ・The resolution is high, but the speed command value B
It is necessary to perform sampling N times until it calculates , and this requires time, so the reaction is slow and there are problems in that it cannot be used in cases where the speed command constantly fluctuates.

This invention was made in order to solve the above problems, and its purpose is to obtain a speed control device that can closely follow changes in speed commands and can perform control using high-resolution actual speed command values. do.

[Means for solving problems]

The speed control device according to the present invention includes: a difference value calculation means that calculates a difference between count values of a counter at fixed time intervals; and a first speed command value calculation means that multiplies the latest difference of the difference value calculation means by N. , a second speed command value calculation means for summing the latest N differences of the difference value calculation means; and a second speed command value calculation means for determining whether or not there is a change in the speed command voltage, and outputting from the first speed command value calculation means when there is a change. and selecting means for selecting the output of the second speed command value calculation means as the actual speed command value when there is no change.

[Effect]

In this invention, the first and second calculation means calculate a first speed command value obtained by multiplying the latest difference of the counter by N, and a second speed command value obtained by summing the difference of the latest N times of the counter. The selection means determines whether or not there is a change in the speed command voltage.

By selecting the first speed command value when there is a change and the second speed command value when there is no change as the actual speed command value, it is possible to follow changes in the speed set value and achieve high resolution. This enables control using actual speed command values.

〔Example〕

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention, and the same reference numerals as in the conventional device shown in FIG. 3 indicate the same elements. For α swords other than those shown in Fig. 3, a difference value calculation means (2) is used to calculate the difference between the count values of Calantuff 8) at regular intervals. first speed command value calculation means for calculating a speed command value by multiplying the difference by N;
αB) is a second speed command value calculation means that totals the latest N differences among the n differences calculated by the difference value calculation means (6), and - is based on the output of these speed command value calculation means. The presence or magnitude of a change in the speed command voltage of the speed setter (1) is determined based on the change, and when there is a change, the output of the first speed command value calculation means is calculated, and when there is no change, the output of the first speed command value calculation means is calculated, and when there is no change, the second speed command value calculation means is Select the output of each means.

The selection means for outputting the actual speed command value is a speed calculation means that performs speed calculation and speed compensation processing using this actual speed command value.

It should be noted that the functions from the difference value calculation means (9) to the speed calculation means described above are provided with the functions of the above-mentioned nine microcomputer (5). The operation of this embodiment will be explained below according to the flowchart of FIG.

First, the microcomputer (5) runs step (121)
) reads the counted value of the counter (8), calculates the difference an from the previous counted value, and then in step (1n)
This difference an is multiplied by an integer N to calculate a speed command value A shown in the following formula.

A=N

B: an44-N H+2-u””+an and,
In the next step (124), in order to check whether there is a change in the speed command voltage, the above-mentioned psychospeed command values A and B are
Substitute into the conditional expression below and check whether this condition is satisfied.

Here, if this condition is not satisfied, it is determined that the speed command voltage has changed, and the next step (125
) to select the speed command value A as the actual speed command value. If the above conditions are satisfied, it is determined that the speed command voltage has not changed, and the speed command value B is selected as the actual speed command value in step (126).
In step 26), speed calculation and speed compensation processing are performed based on the selected actual speed command value.

Thus, according to this embodiment, when there is a change in the speed command voltage, the sampling time can be shortened to speed up the response.
Conversely, when there is no change in the speed command voltage, the resolution of the speed command voltage can be improved by lengthening the sampling time.

In the above embodiment, a conditional expression with an equality sign and an inequality sign is used, but substantially the same operation as described above can be performed by using a conditional expression with only an inequality sign instead.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, when there is a change in the speed command voltage, the sampling time is shortened, and when there is no change in the speed command voltage, the sampling time is lengthened to calculate the actual speed command value. Therefore, it is possible to closely follow changes in the speed command and to perform control using a high-resolution actual speed command value.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.
FIG. 2 is a flowchart for explaining the operation of the same embodiment, FIG. 3 is a block diagram showing a schematic configuration of a conventional speed control device, and FIGS. 4 and 5 are flowcharts for explaining the operation of the same device. It is a flowchart. (1): Speed setter (2): Voltage-frequency converter (8): Counter (5) Two microcomputers (2): Difference value calculation means (2): First speed command value calculation means α■: Second speed command value calculation means CI control: Selection means ■): Speed calculation means Note that the same reference numerals in each figure indicate the same or equivalent parts.

Claims (2)

[Claims] (1) Convert speed command voltage to pulse frequency and
A speed control device that counts converted pulses with a counter and calculates an actual speed command value based on the counted value, comprising: a difference value calculating means that calculates a difference between the counted values of the counter at regular intervals; where N is an integer, a first speed command value calculation means that multiplies the latest difference of the difference value calculation means by N, and a second speed command value that totals the latest N differences of the difference value calculation means. and a calculation means, which determines whether or not there is a change in the speed command voltage, and outputs an output from the first speed command value calculation means when there is a change, and outputs an output from the second speed command value calculation means when there is no change. A speed control device comprising: selection means for selecting an actual speed command value. (2) The output of the first speed command value calculation means is A, the output of the second speed command value calculation means is B, and the selection means satisfies the following equation A-N/2≦B≦A+N/2. When the conditions are satisfied, select B as the actual speed command value,
The speed control device according to claim 1, wherein when this condition is not satisfied, A is selected as the actual speed command value.