JPH01238482A - Speed controller - Google Patents

Abstract

PURPOSE:To speed-control a motor in a high accuracy by obtaining data regarding the irregularity of an FG pulse during several resolutions from a constant speed at the time of motor start, and compensating it therewith. CONSTITUTION:When the start command of a motor is output, a CPU 1 starts a motor 5. When attainment of the motor to a normal speed is detected from the value of a counter 4 for counting an FG pulse, data regarding the irregularity of the FG pulse is obtained during several revolutions. The speed of the motor is controlled by adding a correction on the basis of the data. Thus, even a motor having low accuracy of the FG can be accurately speed-controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a speed control device for a motor used in, for example, a video tape recorder (VTR).

[Conventional technology]

Conventionally, motor speed control has been performed on the premise that the FG accuracy is very high.

(Problem to be Solved by the Invention) However, the conventional speed control device has a drawback that jitter cannot be reduced unless the FG accuracy is good.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide a device that can control speed with high precision.

[Means to solve the problem]

The present invention includes a counter that counts FG pulses of a motor, a data creation means that uses the measured value of the counter to create data regarding variations in FG pulses during several rotations after the motor reaches a constant speed, and The invention is characterized by comprising means for correcting the rotational control of the motor by °C based on the data of the generating means.

[For production]

According to the present invention, for example, when starting the motor, data regarding FG variation is obtained during several rotations after reaching a constant speed, and the data is used to make corrections to control the speed of the motor. Accuracy can be improved.

〔Example〕

1 to 3 show embodiments of the present invention, FIG. 1 is a block diagram of the embodiment of the invention, FIG. 2 shows the waveform of the FG pulse, and FIG. 3 is a flowchart of the embodiment. It is.

Reference numeral 2 in FIG. 1 denotes a RAM for recording data for correction, and includes P and N as described later.

It has registers such as C and lip. 3 is a driver for rotating the motor 5; 4 is a counter for calculating the FG ratio output a) shown in Fig. 2; 1 is a RAM 2, which processes the human power from the counter 4 and outputs a control value to the driver 3; It is a CPU that performs

Counter 4 latches the count value at the rising edge, and [
1: PU1 reads the latched value. Furthermore, the counter 4 is cleared to 0 at the same time as the latch.

The present invention will be explained in detail using the flowchart shown in FIG.

First, in step (hereinafter referred to as S) 1, a start command for the motor is waited for, and when the start command is received, the motor is started in 52. Next, wait until FG rises in S3, and then switch to S4.
Enter the value of counter 4 with . Next, in S5, it is determined whether the speed has reached an almost constant speed (for example, 95% of the constant speed) from the manually input value, and if it has not reached it, then the S speed is continued until the constant speed is reached.
3. Repeat S4 and S5. When the speed becomes almost constant, the process goes to S6, waits until FG rises, and inputs the value of counter 4 in S7.

Then, in S8, speed control without correction is performed, and in S9, it is determined whether the steady speed has been reached. If the steady speed has not been reached, S6, S7, S8, and S9 are repeated until the constant speed is reached.

When the speed becomes constant, the process advances to 510 and registers P and N are set to O. Next, in step 511, the program waits until the FG is set up, and in step 512, the value of the counter is entered manually, and that value is set as C.

Then, in S13, C-Go is added to lip. Note 11
Clear p to 0 at the start. co is the value of the counter at constant speed when there is no sick.

Then, in step 514, control is performed so that no correction is performed, and in step 515, 1 is added to P. Next, in 516, it is determined whether P is equal to Po, and if not, Sll is held until they become equal.
Repeat 518. Po is the number of FGs in one rotation.

If they are equal in S16, the process proceeds to 517, where P is set to 0 and N is incremented by 1.

Next, in 518, it is determined whether N is equal to No. If not, steps 511-518 are repeated until they become equal. NO is an integer of 1 or more.

If they are equal at 518, the process advances to S19 and up(p-o
~Po-1) divided by No. At this time, round up and round down so that the sum of Hp becomes 0.

Next, in step 520, it waits until FG rises, and in step 521, the value of the counter is input manually. Then, in S22, speed control with correction is performed. To show an example of correction calculation, for y=, (C+H
p-Go) 10 to 2Σ(C+1Ip-Go) + K3y
:Control value C: Counter value 1, K2, K, :Constant Calculate by the formula shown above and add I(p as a correction term.In addition, control without correction is from the above equation) Ip. This is what I took.

Then, in 523, let P be the remainder of Pal divided by Po.

520 to 52 until the motor stop command comes at 524
4 is repeated, and when a stop command is received, the motor is stopped in S25 and the process returns to Sl.

〔Effect of the invention〕

According to the present invention, it is possible to control the speed with high precision even with a motor whose FG is not accurate, and it is possible to reduce sick, for example, and to facilitate adjustment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of an embodiment of the present invention, Figure 2 is a diagram showing the waveform of the FG pulse; FIG. 3 is an operational flowchart 1- of this embodiment. Figure 1 Figure 2

Claims (1)

[Claims] 1) a counter that counts the FG pulses of the motor; a data creation means that uses the measured values of the counter to create data regarding variations in the FG pulses during several revolutions after the motor reaches a constant speed; A speed control device comprising: means for correcting rotational control of the motor based on data of the means.