JPS602085A - Speed controller for motor - Google Patents

Abstract

PURPOSE:To accurately control a motor with an inexpensive electric circuit by raising the resolution by multiplying the output signal of an encoder. CONSTITUTION:The title controller has a rotary encoder 10, a multiplier 20 for multiplying the output signal, a multiplication signal number discriminator 40 for discriminating what the multiplication signal is in number, a memory 50 for storing the periodic error data between the multiplication signals measured in advance in response to the signal number of the multiplication signal, an error signal generator 60 for generating the error signal by reading out the periodic error signal corresponding to the multiplication signal number from the memory, a control circuit 80 for generating a motor control signal SC corrected for the periodic error of the multiplication signal by inputting the signal, and a drive circuit 100 for driving the motor 1 by the motor control signal SC.

Description

DETAILED DESCRIPTION OF THE INVENTION In the present invention, the rotational speed 17-C of the motor is detected by a rotational position rotary encoder, and the detected signal is compared with a sound reference signal to determine the motor speed? The present invention relates to a speed control device for a motor to be controlled.

One example is a conventional motor speed control device.

A pulse generator directly connected to the rotor shaft of the motor detects the pulse signal sound outputted from it, and compares this with the reference norm signal to obtain a speed deviation signal. In addition, the trap signal is proportional to this deviation signal, and 7ζ is widely used in order to fully control the speed of the trap signal.

Is the pulse generator mentioned above magnetic? There are different types of encoders and optical types, but recently the optical type is the most widely used type, and rotary encoders are now referring to all types of optical type encoders.

Optical rotary encoders currently on the market include:
Various resolutions (number of divisions per 7 times) depending on the purpose?
As more and more devices have crystallized resolution, their prices are rapidly increasing. For example, if the IL has a resolution of i, ooθ pulse/rotation, it will cost less than 20,000 to 30,000 yen, S,
A device with a resolution of about OOθ pulses/rotation costs about 60,000 yen, and a device with a high resolution of 10°,000 pulses/rotation or higher costs more than 300,000 yen.

However, if a high-resolution rotary encoder is used to control the motor at a low speed with high precision, an increase in cost is unavoidable.

The present invention was created in view of these circumstances.

An inexpensive low-resolution rotary encoder? Use motor speed control? It is an object of the present invention to provide a speed control device that is highly accurate and can be implemented as an inexpensive VC.

The speed control device of the present invention uses an inexpensive low-resolution rotary encoder and multiplies its output to increase the resolution.The periodic error of the multiplied signal caused by multiplication is measured in advance. 1 cycle error? The control signal of the trap motor is corrected and the control signal is obtained to improve the control. : Is it the rotation position? A rotary encoder to be detected, a multiplier circuit that multiplies the output signal of the rotary encoder to generate a multiplier signal, and a multiplier signal number determination device that determines the number of the multiplied signal. and a memory that stores periodic error data measured in advance between the multiplied signals in association with the signal number of the multiplied signal, based on the judgment result of the multiplied signal number judgment circuit. The periodic error data corresponding to the multiplication signal number? an error signal generation circuit that reads out the error signal from the memory and generates the error signal; an +aIJ control circuit that inputs the error signal to correct the periodic error of the multiplied signal and generates a π motor control signal sound; It is characterized by having a drive circuit for driving a motor and a metal.

Hereinafter, embodiments of the present invention will be explained in detail with reference to one drawing.

u! 1 is a block diagram showing the overall configuration of a motor speed control device according to an embodiment of the present invention.

In FIG. 1, a rotary encoder 10 is connected to a motor l.
It is connected to the rotor shaft by a coupling 1],
7λ sine wave signals with a phase difference of Oo? This is what is output.

The multiplier circuit 20 synthesizes two sine wave signals having a phase difference of O゛ from the rotary encoder/θ and generates a plurality of intermediate phase signals having mutually equal phase differences during one period of the original sine wave. Create a complete sine wave signal with the same phase difference, and shape the resulting multiple sine wave signals with equal phase differences to form a rectangular wave. Combine all of the rectangular waves obtained during the period of one original sine wave. This is a circuit that generates

Generally, when <'n @ sound signals are generated during one period of the original signal, it is said to be multiplied by n.
is a circuit that completely determines which scan-th signal it is among the n multiplied signals.

The memory to stores period error data of the 7'lπ multiplied signal measured in advance in association with the signal number of the multiplied signal.

The error signal generation circuit ΔO generates cycle error data corresponding to the multiplication signal number based on the multiplication signal number judgment circuit of the multiplication signal number judgment circuit HIRO0. memory! This is a circuit that reads data from O and generates an error of 1g.

The control circuit O is a circuit that receives the error signal from the error signal generation circuit to, corrects the periodic error of the multiplied signal, and generates all the motor control signals whose periodic errors have been corrected f'.

The drive circuit 100 is a trap circuit that drives the motor l' using a motor control signal from the control circuit ♂O.

The above is the overall configuration of the speed control device. First, each of the above-mentioned circuits will be explained in detail.

FIG. 2 is a block diagram showing details of the multiplier circuit 20.

71 knee two sine waves with 20° phase difference from each other from rotary encoder IO i.e. 5ine, cos
The signals of ine are input to each of the synthesis circuits l to j, and are synthesized as shown in Fig. 3 (A) fc with a phase shift of π.
Sine wave signals S2 to S5. The amplitude is the same and the phase is 3.
A sine wave t0 is created by tl-π. Regarding Tradashi Synthesis Circuit 21.

5ine-cosin? The signal Ig is not synthesized and the sine wave signal S1 is output as is. Waveform shaping circuit, 2
6 to 30 are waveform-shaped into rectangular wave signals SRI to sR5 as shown in sine wave signals s, -8s total -8s B). Next, the rectangular wave signals SRI to SR5 are input to the arithmetic circuit 3/vc and are logically combined, and as shown in FIG. In this case, a signal of signal level l is generated.

One period of the original sine wave signal S1 is multiplied by j and a multiplied signal Sm (Sm1 to Sm5) is output from the arithmetic circuit 3/49.

The multiplied signal created in this way includes an error due to its period (interval between signals, NC electric circuit). Each sine wave signal 81 to
Variations occur in the phase difference between S5. Therefore, variations occur in the cycles of the multiplied signals Sm1 to Sm5, and it is impossible to obtain highly accurate multiplied signals unless this variation is corrected. Note that the accuracy of the period of the output from the rotary encoder io, that is, the sine wave signal S1 itself, and the period of the synthesized signal n7 (sine wave signals 82 to S5 itself) is extremely high compared to the accuracy of the period of the multiplied signal.

Next is the periodic error of the multiplied signals Sm1 to Sm5? The method of finding and correcting it will be explained.

The rotary encoder 10 and the multiplier circuit 2o to be used are connected to a reference motor whose rotor has a large inertia and a small variation in rotational speed, and the period of the obtained multiplied signal fL is measured.

Figure ≠ is a π-th diagram explaining the method of completely correcting the periodic error of the multiplied signal.
Only the position that changes from 1 to 1) is fully displayed.

Figure (A) shows the ideal period of the multiplication signal at the target speed to be controlled. FIG.

Figure (B) shows the multiplied signal Sm1 containing the actual periodic error.
It is a diagram showing ~Sm5k. In the figure, each signal Sm2, S
m3. Sm4. Sm5 has period errors of Δt2 leading, Δt3 delay n, Δt4 delay n, and Δt5 delay n with respect to the n-f:'n ideal signal. In addition.

The periodic errors Δt2 to Δt5 with respect to the ideal period can be actually measured using an oscilloscope or the like. In this case, the signal with the maximum delay n with respect to the ideal signal is Sm15, but the signal Sm5 matches the ideal signal as shown in Fig.
Figure (C) is a trap in which the signal train in B) is moved to the left by a distance of Δt5 in the figure.

As is clear from Fig. 1 (C), in order to completely correct the periodic error of the multiplied signal, each signal S, 1, Sm2, Sm3, Sm
4, n-enΔt5, △t5+△t2゜△t5-△t
It is better to delay the time by a, Δt5 - Δt4 time.

Therefore, first of all, regarding the multiplier (No. A signal determination circuit ≠ O, for example, a well-known counter and decoder can be used, so the details of the circuit #IFi are omitted, but the multiplier circuit θ sequentially outputs the multiplier signals Sm1 to Sm5 from the output source IL). All signal numbers are determined and a signal tone is output indicating whether the signal number is izn- of /~j.

Next, the error signal generation circuit to generates periodic error data (multiple signal r ideal period 1i41)' memory s is required for the πth continuation that matches .

The signal Sef is read out and inputted to the control circuit ZO.

Note that the memory 10 can be, for example, a PROMk,
A pre-measured delay time corresponding to each signal number is stored. That is, signal number/[correspondingly △t5
．． Corresponding to signal number 2T/C, △t5+△t2. Delay times Δt5-Δt3 are stored corresponding to signal number 3, and delay times Δt5-Δt4 are stored corresponding to signal number 8.

Next V? A block diagram showing the details of the control circuit is shown in Figure J.

The AND game 1-J'/ receives the multiplied signal Sm and the period measuring clock, and its output is inputted to the counter Jl. A reset pulse R is input to the counter 2 at the timing of the rise of the multiplied signal 5rTl. Start counting all reference clocks. The count signal is sequentially input to the comparator 3. Comparator r3 memory jO
The tl-trap cycle difference data signal Se read from the counter 1.2 is compared with the count number of the reference clock from the counter 1.2, and if the difference is θ, a signal St ratio is output. That is, the comparator 3 outputs a multiplied signal S which is obtained by delaying the multiplied signal Sm by the period of the periodic error data signal Se and correcting the π periodic error.

The period is corrected and the reference signal S for speed setting is obtained by f′Lπ multiplication signal multiplication signal comparison circuit r≠. The motor is controlled by this difference signal. This comparison circuit J4 can use various known methods depending on the control method of the motor, for example, the reference signal S.

The period is corrected and the phase difference between the multiplication signal +58 is detected and the trap motor control signal S is generated according to the difference. It may be of a type that generates a sound, or the period of the reference signal So (corresponding to the standard speed) and the period of the nπ multiplier signal (corresponding to the speed detected by devitrification during motor control) whose period is corrected. )?
Detect and control the trap motor according to the difference. It may also be of a type that generates sound. Alternatively, both the π and π expressions may be used in combination.

The agitation circuit 100 generates a $ signal S based on the trap multiplication signal S' whose period is corrected by the motor control signal S0. , i.e. position 1, 7? : is a circuit that drives the rotor of the motor to full rotation so that the speed is set to O.

In the control circuit ♂O mentioned above, the periodic error is corrected n, 7 (the multiplied signal S and the reference signal S.
'l 7c motor control 1g S. VC to generate sound
+14 lJy, but the periodic error is corrected by the method shown in Figure V. The trap motor control signal S.

? It may be made to occur.

The comparison circuit ♂Y is a circuit that operates in the same manner as the above-mentioned comparison circuit ♂Hiroshi, and is a circuit that performs the same function as the reference signal S. and the multiplied signal Sm containing periodic error in? Compare the motor control signal S. ′(multiply(
R-1: This is the circuit that generates the cycle error of Sm. Adder and 6 are motor control signals S. ' and the periodic error data signal Se of the error signal generation circuit 60 and
The periodic error is corrected by calculating 710 and 'fl, π motor control signal S. r is generated.

As described above in detail, according to the present invention,
By using a low-resolution encoder and multiplying the encoder's output by VC, is the resolution determined by VC? Measure in advance the periodic error of the multiplied signal that occurs due to multiplication. It is configured to correct and obtain the control signal of the trap motor, and it uses an inexpensive electric circuit sound without using a high-resolution, expensive encoder.
The motor can be controlled at t7 u'l.

Features ff (X) The invention can control the speed of a low-speed rotary motor with a long output signal period from a rotary encoder to achieve high tree fatigue.

[Brief explanation of the drawing]

&τ/ Fig. 2 is a block diagram showing the entire structure of a motor speed control device showing one embodiment of the present invention, Fig. 2 is a block diagram showing details of the multiplier circuit in Fig. 1, and Fig. 3 is a block diagram showing the details of the multiplier circuit in Fig. 1. A trap diagram explaining how to generate it. The figure below shows how to correct the periodic error of the multiplied signal. A diagram of a trap to explain. Figure 5 shows a detailed example of the control circuit in Figure 1: u
'fr: Block diagram shown. FIG. 6ζ1 Details of another embodiment of the control circuit in FIG. 1'? 6: This is a complete block diagram. /...Motor 10...0-Yu IJ-Encoder,! 0...
...Multiplier circuit OG...Multiplier signal number Profit circuit 5θ...
・Memory (, 0...Error ・1g generation direction path go...
・Control circuit 100...Drive circuit

Claims (1)

[Claims] 1. (1) A rotary encoder for detecting the rotational speed or rotational position of the rotor of the motor, and a multiplier circuit for multiplying the output signal of the rotary encoder to generate all multiplied signals. θ a multiplied signal determination circuit connected to the multiplier circuit and which determines the number of the multiplied signal; 0 has a trap memo 'Jk in which periodic error data between the multiplied 4W signals measured in advance is stored in association with the signal arrival strength of the multiplied signal, and based on the judgment result of the multiplied signal number judgment circuit, an error signal generation circuit that reads the periodic error data corresponding to the multiplied signal number from the memory and outputs an error signal; (2) A control circuit that inputs all of the error signals and generates an n-trap motor control signal by correcting the periodic error of the multiplied signal, and a drive circuit that drives the motor using the 4Q motor control signals. Motor speed control device. 2. The motor control signal is a difference signal between a correction signal obtained by delaying the multiplied signal in accordance with the error signal and a predetermined nπ reference signal. 2. The motor speed control device according to item 1. 3. The motor control signal is a signal obtained by correcting a difference signal between the multiplied signal and a predetermined reference signal tL7 (reference signal) in accordance with the error signal. Motor speed control device.