JPS62178183A - Servo-device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a servo device that controls the rotational speed of a rotating body to quickly reach a desired value when the rotating body is started.

Conventional technology A signal obtained by comparing the output of a speed generator, which generates a signal with a frequency corresponding to the rotational speed of a rotating body such as a motor, and the output of a voltage source, which generates a preset output voltage. A method of performing more precise control than when controlling based on the frequency of the output signal of the speed generator is described in detail in Japanese Patent Application No. 59-214544 by the same applicant as the present application.

In the previous application, it was explained that after the motor is fully accelerated by outputting the maximum error signal at startup, the rotational speed gradually increases, and then transitions to highly accurate control near the set speed.

Problems to be Solved by the Invention However, with the above configuration, when the load on the motor is light or the set speed is low, the set speed may be exceeded before it is ready to shift to high-precision control. It may not be possible to smoothly transition to high-precision control,
Another problem is that it takes time to settle to the set speed.

In view of the above-mentioned problems, the present invention provides a servo device that quickly brings the rotational speed of a motor close to a set speed at startup and smoothly shifts to highly accurate control.

Means for Solving the Problems In order to solve the above problems, the servo device of the present invention includes a voltage source that generates at least two preset output voltages, and a combination of the output of the voltage source and the rotating body. A comparator that compares the potential of an AC signal having speed information and generates an output signal twice or more during a half cycle of the AC signal, and calculates an error output from the cycle of the output signal of the comparator and a reference value. a computing unit for supplying driving power to the rotating body based on the error output; and a driving means for supplying driving power to the rotating body based on the error output; a status detection means that generates a detection signal when the output signal is normally output; and a status detection means that generates a detection signal when the output signal is outputted normally; The present invention is characterized by comprising a switch means for switching between a servo loop that causes the output to be calculated and a servo loop that causes the arithmetic unit to calculate the error output based on the period of the output signal of the comparator and the reference value.

Effect of the present invention With the above-described configuration, each time the output signal of the speed generator of the motor passes a zero cross at the time of starting, the reference value of one period of the AC signal and one period of the output signal of the speed generator "Qt" is set. The arithmetic unit calculates the error output and drives the motor based on the error signal, so the rotation speed can be quickly brought close to the set speed even when the load on the motor is light or the set speed is low. Therefore, the transition to highly accurate Fill?[I can be performed smoothly.

EXAMPLE Hereinafter, a servo device according to an example of the present invention will be described with reference to the drawings.

FIG. 1 shows a servo device in a first embodiment of the present invention. In FIG. 1, the output of a speed generator a (-1a is called a frequency generator or simply FC) 2 connected to a motor l is amplified to a certain voltage level by an amplifier 3, and then converted into a rectangular wave by a waveform shaper 4. is amplified until .

The output of the waveform shaper 4 is supplied to a channel selector 5, which generates a signal for selecting the channel of the programmable voltage I16 and a status signal indicating the status of the channel selector 5 to the processor 7. is supplied to the programmable voltage source 6 and the processor 7 via a control bus 8.

Further, the output signal of the amplifier 3 is sent to a non-inverting input terminal 9a of a first comparator (indicated as comparator 1 in the figure) 9 and a second comparator (indicated as comparator 2 in the figure). ) IO inverting input terminal 10b
is supplied to.

Furthermore, the output signal from the upper output terminal 6a of the programmable voltage source 6 is supplied to the inverting input terminal 9b of the comparator 9, and the output signal of the programmable voltage source 6 is supplied to the non-inverting input terminal 10a of the comparator IO. An output signal from the lower output terminal 6b is supplied, and a voltage comparison with the output signal of the amplifier 3 is performed in each comparator, and the comparison output signal is supplied to the channel selector 5 as a channel update signal.

Further, when the waveform shaper 4 and the comparators 9 and 10 each output an output signal, a timing signal is outputted from the timing signal output terminal 5a of the channel selector 5 and supplied to the period detector 11. The period detector 11 measures the period of the timing signal output from the timing signal output terminal 5a, that is, the period of the output signals output from the waveform shaper 4 and the comparators 9 and 10, respectively, and connects the data bus 12. The memory 7 of the processor 7 via
Supply to C. The memory 7C stores periodic data at an address dependent on status (No. 3).

Next, in the processor 7, a status signal sent from the channel selector 5 via the control bus 8 and a status signal sent from the period detection means 11 via the data bus 12 are stored in the memory 7C of the processor 7. The arithmetic unit 7b calculates the speed error signal of the motor l from the cycle data, and the calculated output is sent to the servo loop switch 7.
d and a data bus 13 to a digital-to-analog converter 14. The output of the digital-to-analog converter 14 is amplified by power amplifiers (indicated as power amplifiers in the figure) 1 and 5 and supplied to the motor 1 as driving power.

Figure 2 shows the first speed when the speed of motor 1 reaches the set speed.
A waveform diagram of each block in the figure is shown. Figure 2 (
al is an output signal waveform diagram of the amplifier 3, and FIG.
is an output signal waveform diagram of the waveform shaper 4, and FIG.
, (di is the output terminal 6a, 6 of the programmable voltage source 6
The signal waveforms appearing in FIG. (gl is a signal waveform appearing at the timing signal output terminal 5a of the channel selector 5.

Now, based on FIGS. 1 and 2, an outline of the operation of the system when the motor 1 is rotating at a set speed will be explained.

First, the output signal of the speed generator 2 attached to the motor 1 is amplified by the amplification 2ii3. The amplifier 3
When the signal level of the output signal passes through the zero cross at time t1 and changes from negative potential to positive potential, the output of waveform shaper 4 changes from low level to high level, but comparator 9
．． The level of the IO output terminal does not change. Next, at time t2, the amplitude of the output signal of the amplifier 3 increases and exceeds the signal level L3 of the output terminal 6a of the programmable voltage source 6, and the level of the output signal of the comparator 9 changes from low level to high level. The channel selector 5 sends the status signal to the control bus 8.
output terminals 6a, 6 of the programmable voltage source 6.
The output levels of L2.b and L2. Make it L3. As a result, the output of comparator 9 becomes low level again.

The output level of the programmable voltage [6 is a voltage level that equally divides one cycle of the output signal of the amplifier 3 into eight, and is based on the following equation.

Vn-Vp-3i n (n ・i/4-θ) (1) However, n=1. 2 In equation [1], Vp is the amplitude of the output signal of the amplifier 3 when the motor 1 is rotating at the set speed.

The value of θ is set to π/8 in the example. Figure 2 te1. The relationship between the output level 1 to L6 of the programmable voltage source 6 shown in fdl and Vn is as follows.

L1=Vm 2- v2 L3=V.

L = -V.

L = -V2 L a =V rn
(21 Here, Vm is a slightly larger value than Vp.

At time t3, the amplitude of the output signal of the amplifier 3 further increases and when it exceeds the level L2, the output signal of the comparator 9, the channel selector 5. The programmable voltage source 6 operates in the same manner as at time t2, and the level of the output signal of the comparator 9 changes from low level to high level and then to low level again. And output terminal 6a of programmable voltage 'a6
, 6b respectively become L2.

When the amplitude of the output signal of the amplifier 3 passes the peak and begins to fall, and at time t4 the amplitude of the output signal of the amplifier 3 becomes smaller and becomes lower than the level L2, the comparator lO
The output level of changes from low level to high level, channel selector 5 outputs a status signal to control bus 8, and output terminal 6a of programmable voltage source 6,
The signal level of 6b is L2. Becomes L3. As a result, the output of the comparator IO becomes low level again. Time t5.
t7. The same operation is repeated for t8.

Further, the amplitude of the output signal of amplifier 3 becomes smaller, and time t
6, when the output of the amplifier 3 passes the zero cross and the amplitude level changes from positive potential to negative potential, the level of the output signal of the waveform shaper 4 changes from high level to low level, but comparator 9. The level of the IO output terminal does not change as at time 11.

At time t8, the signal levels of the output terminals 6a and 6b of the programmable voltage tA6 are respectively L5°L.

When the peak point of the output No. 13 of the amplifier 3 has passed and the amplitude level becomes higher than the output level L5 of the output terminal 6a of the programmable voltage source 6 at time t9, the comparator 9
The output of the channel selector 5 changes from low level to high level, and the channel selector 5 outputs the output terminal 6a of the programmable voltage source 6.
, 6b are respectively L4. A status signal is output to the control bus 8 so that the signal becomes L5. A similar operation is performed for time tlO.

That is, the comparator 9 is effective in the section where the output of the amplifier 3 is increasing as shown in FIG.
The comparator 10 is effective during the period in which the output of the amplifier 3 is decreasing, as shown in +fl in FIG. and,
The sum of the effective output signals of comparators 9 and 10 is shown in Figure 2 (
The signal appears like an illusion and is output from the timing output terminal 5a of the channel selector 5 to the period detector 11 as a timing signal.

Therefore, if the relationship between the output signal of the amplifier 3 and the output signal of the programmable voltage source 6 whose level is determined by the channel selector 5 is operating normally, the signal waveform of the output terminals 6a and 6b of the programmable voltage source 6 is has a waveform as shown in FIG.
Whether the relationship between the output signals is operating normally can be determined by monitoring the status signal of the channel selector 6.

However, since the rotational speed of the motor 1 is low at startup, the level of the output signal of the speed generator 2 is also low, and even after being amplified by the amplifier 3, the level of the signal remains unchanged from the programmable voltage source 6.
The level output from the output terminal 6a of 2. The output level L5 of the output terminal 6b is not reached. Therefore, the relationship between the output of the programmable voltage source 6 and the output of the amplifier 3 is not normal as shown in FIG.

Now, Figure 3 shows the signal waveforms of the main parts of the system in Figure 1 when the motor l starts, and Figure 3 (
al is an output signal waveform diagram of the amplifier 3, and FIG.
is an output signal waveform diagram of the waveform shaper 4, and FIG.
, (dl is the output terminal 6a of the programmable voltage source 6,
6b, and is the signal waveform appearing in FIG. 3 te1. (fl
are each comparator 9. Of the signals appearing at the output terminal of the IO, this is a signal waveform that operates as a valid signal in the channel selector 5, as shown in FIG. 3 (gl is the signal waveform appearing at the timing signal output terminal 5a of the channel selector 5, is the signal waveform of the status detector 7a.

Now, based on the first UfJ and FIG. 3, an overview of the system operation at startup will be explained.

First, at time t1, starting power is supplied to the motor 1 and it begins to rotate. At that time, the channel selector 5 sends a signal to the control switch 8 to set the programmable voltage source 6 to the initial value.
Output terminal 6a of programmable voltage 'tX6
, 6b becomes L3.L4 as shown in FIG. 3 [C1, (dl).

Next, when the motor 1 starts to rotate gradually, the output of the speed generator 2 attached to the motor 1 increases in proportion to the rotation speed, and therefore the output of the amplifier 3 also increases as shown in FIG.
The level of the output signal of the waveform shaper 4 increases as shown by +, passes through the zero cross at time c2, and increases toward the negative polarity. The signal changes from high level to low level, channel selector 5 generates a timing signal, period detector 11 detects the period between time tl and time t2, and sends period data to memory 7c of processor 7 via data bus 12.

At time t2, the output signal of the speed generator 2 has only been output for half a cycle, so the arithmetic unit 7b of the processor 7
For example, an error [J] is calculated from the value of the cycle data and 1/2 of the reference value for one cycle, and the calculation result is output to the digital-to-analog converter 14, and the power amplifier 15 drives the motor.

When the output of the amplifier 3 becomes smaller than the output level L4 of the output terminal 6b of the programmer pull voltage source 6 at time t3, the output level of the comparator IO changes from low level to high level. As a result, the channel selector 5 outputs a status signal to the control bus 8, and the levels of the output signals at the output terminals 6a and 6b of the programmable voltage source 6 become L5, and the comparator 1
The output level of 0 changes from high level to low level.

Since the rotation speed of the motor 1 is low, the output signal level of the amplifier 3 does not become smaller, so the output level of the comparator IO does not change. Therefore, the relationship between the output signal of the amplifier 3 and the output signal of the programmable voltage source 6 is
This is not a normal relationship as explained in the figure.

At time t4, the output signal of amplifier 3 passes through the zero cross again. At that time, the channel selector 5 is initialized by the output signal of the waveform shaper 4, and the output terminal 5a of the programmable voltage a16 is output.

The level of the output signal of 6b is respectively ,L.

becomes. Here, the channel selector 5 generates a timing signal at time t4 when the zero cross is passed.

The period detector 11 detects the period between time t2 and time L4, and transfers the period data to the memory 7C of the processor 7 through the data bus 12.
Send via. That is, the memory 7C stores period data from the rising edge to the falling edge of the waveform shaper 4. The calculator 7b of the pro sensor 7 calculates the period of 1 cycle by adding the period data of the half cycle of the amplifier 3 at time t2 and the period data of the half cycle of the amplifier 3 at time [4, An error output is calculated from the cycle reference value, the calculation result is output to the digital-to-analog converter 14, and the power amplifier 15 drives the motor l.

The level of the output signal of the amplifier 3 increases and becomes thicker than the output level L3 of the output terminal 6a of the programmable voltage source 6 at time t5 (then the output signal of the comparator 9 becomes high level and the channel selector 6 changes the output of the comparator 9 to When the status signal becomes high level, the status signal is output to the control bus 8, and the output level of the output terminals 5a, 5b of the programmable voltage a6 is set to L2.L3.The output level of the programmable voltage source 6 is set to 1,
2. At L3, the output level of the comparator 9 changes from high level to low level.

The output signal of the amplifier 3 further increases and reaches the peak point, but since it does not exceed the voltage level L2 of the output terminal 6a of the programmable voltage 'a6, the output signal of the comparator 9 does not become high level again and becomes zero at time t6. When the cross 111iIA is pressed, the channel selector 5 is reset, and the output levels of the output terminals 5a and 5b of the programmable voltage source 6 are set to L3. It becomes L. Here, the channel selector 5 generates a timing signal at time t6 when the zero cross is passed, the period detector 11 detects the period between time t4 and time t6, and sends period data to the memory 7C of the processor 7 via the data bus 12. Send. That is, memory 7C
Stores periodic data from the rising edge to the falling edge of the waveform shaper 4. processor 7
The arithmetic unit 7b adds the periodic data of a half cycle from the falling edge to the rising edge of the amplifier 3 at time t4 and the periodic data of a half cycle from the rising edge of the amplifier 3 to the falling edge at time t6. The period of one cycle is calculated, and the error output is calculated from the period and the reference value of one cycle.The calculation result is output to the digital-to-analog converter 14, and the motor 1 is driven by the power amplifier 15.

Here, the reason for calculating the period of one cycle by adding the period data of a half cycle and obtaining the error output is because if the error output is calculated based on the period data of a half cycle, the offset of the waveform shaper 4 etc. This is to avoid the fact that a shift in the duty due to the error occurs in the error output and it is not possible to output an accurate error output.One cycle of the amplifier 3 is measured and the error output calculated based on that cycle is calculated for the next half cycle. It is output for a period. The reason why the output period is set to the period of the next half cycle is to reduce the delay due to hold in the output.

FIG. 4 is a diagram showing the relationship between the measurement period of the output signal of the amplifier 3 and the period during which the error output is output. Figure 4 (a
l is the output signal waveform of the amplifier 3, FIG. 4 (bl is the output signal waveform of the waveform shaper 4, FIG. 4 (C1 is a diagram showing the measurement period, and FIG.

In FIG. 4, each time the output signal of the amplifier 3 passes a zero cross, there is a period of one cycle before the passing time (indicated by α1, α2, α3, . . . in FIG. 4 fcl). ) and the period of the next half cycle (Fig. 4(d)
In l, β1. β2. β3. It is indicated by... ) is outputting an error signal. Time tlo1. t102
．． The reason why the output of the waveform shaper 4 deviates slightly at the zero cross at t103 is due to the offset of the waveform shaper 4 and the like. The measurement periods (α1.α2.α3...) overlap each other by half cycles, and the output periods (β1.β2.β...) overlap each other by half cycles.
3...) changes the output value every half cycle. By doing so, the delay due to hold is reduced compared to measuring the period of one cycle of the output signal of the amplifier 3 and outputting it for the period of the next one cycle.

Next, at time t7, the output signal of the amplifier 3 increases to the negative polarity side (becomes the output terminal 6b of the programmable voltage source 6).
When the output level becomes smaller than the output level of the comparator IO, the output signal of the comparator IO changes from low level to high level, and the channel selector 5 outputs the status (i) to the control bus 8, and outputs the status (i) to the output terminal 5a of the programmable voltage 56.
The output level of L4.5b is respectively L4.5b. The level becomes L5, and the output signal level of the comparator IO changes from high level to low level.

The output signal of the amplifier 3 further increases toward the negative polarity side and reaches a peak point, but the output signal of the programmable voltage source 6
b does not become lower than the voltage level L5, so the output signal of the comparator 10 does not become high level again.
When the zero cross is passed at time t8, the channel selector 5
is reset, and the output terminal 6 of the programmable voltage source 6
a.

The output level of L3.6b is respectively L3.6b. It becomes L.

Here, the channel selector 5 generates a timing signal at time t8 when the zero cross is passed, the period detector 11 detects the period between time t6 and time t8, and the memory 7 of the processor 7
Periodic data is sent to C via the data bus 12. That is, the memory 7c stores cycle data from the falling edge to the rising edge of the waveform shaper 4. The arithmetic unit 7b of the processor 7 is the amplifier 3 at time t6.
Calculate the period of one cycle by adding the period data of a half cycle from the rising edge to the falling edge of the amplifier 3 at time t8 and the period data of the half cycle from the falling edge to the rising edge of the amplifier 3 at time t8,
Calculate the error output from the period and the reference value of one cycle,
The calculation result is output to the DigiCrew analog converter 14, and the motor 1 is driven by the power amplifier 15. The value of the error output at this time is smaller than the value of the error output at t6 because the value of the period of one cycle is close to the reference value.

When the level of the output signal of the amplifier 3 increases and becomes higher than the output level L8 of the output terminal 6a of the programmable voltage source 6 at time [9], the output signal of the comparator 9 becomes high level, and the channel selector 6 changes the output of the comparator 9 to When the level becomes high, a status signal is output to the control bus 8, and the output level of the output terminals 6a and 6b of the programmable voltage source 6 is changed to L2. L3
Set to . The output level of programmable voltage source 6 is L
2. When the signal becomes L, the output level of the comparator 9 changes from high level to low level.

The output signal of the amplifier 3 further increases and reaches a peak point, but since it does not exceed the voltage level L2 of the output terminal 6a of the programmable voltage source 6, the output signal of the comparator 9 does not become high level again (at time tlO). The zero cross is passed, the channel selector 5 is reset, and the output levels of the output terminals 6a and 6b of the programmable voltage source 6 become L3 and L4, respectively.Here, the same operation as at times t6 and t8 is performed, and one cycle is completed. The value of the error output is calculated based on the synchronization, but since the period value is closer to the reference value, the value of the error output becomes smaller.

When the output signal level of the amplifier 3 becomes smaller than the output level of the output terminal 6b of the programmable voltage source 6 at time tll, the same operation as at time t7 occurs, and the output levels of the output terminals 6a and 6b of the programmable voltage fi6 become L4. It becomes L5.

At time 112, the output signal level of the amplifier 3 becomes smaller than the output level L5 of the output terminal 6b of the programmable voltage source 6, the output of the comparator's regulator 10 changes from low level to high level, and as a result, the channel selector 5 changes to the programmable voltage i1. The output levels of !5a and 6b are set to L5. A status signal to be set in L6 is output to the control bus 8. Programmable voltage 111X6
Since the output level of the output terminal 6b becomes L6, the output level of the comparator 10 changes from high level to low level.

The output signal of amplifier 3 passes the peak point and reaches time tt3.
at the output terminal of the programmable voltage source 6.

The output level of the output terminal 6a becomes higher than L5, and the output level of the comparator 9 changes from a low level to a high level.As a result, the channel selector 5 outputs a status signal to the control bus 8, and the output terminals 6a, 6b of the programmable voltage source 6 The output level of L4. L5, and the output level of the comparator 9 changes from high level to low level.

Furthermore, at time t14, the output signal of the amplifier 3 becomes the output level L of the output terminal 6a of the programmable voltage source 6, which is thicker (then the output of the comparator 9 changes from low level to high level, and as a result, the channel selector 5 changes the status (3). output signal to the control bus 8, and the output level of the output terminals 6a and 6b of the programmable voltage source 6 is L.
8. L.

Therefore, the output level of the comparator 9 changes from high level to low level.

Next, when the output signal of the amplifier 3 passes the zero cross at time t15, the channel selector 5 is reset by the output signal of the waveform shaper 4 and the programmable voltage a
The output level of output terminals 6a and 6b of a6 is set to L3. However, since it has already been set at time t14, the output terminals 5a and 5b of programmable voltage R6
does not change at all. Even at time t15, time 110
The value of one period is calculated by adding the value of the period of half a cycle in , and the value of the error output is calculated based on that period, but since the value of the period is closer to the reference value, the value of the error output is becomes smaller than the value at time tlO.

The relationship between the output signal of the amplifier 3 and the output signal of the programmable voltage source 6 is operating normally from time t10 to time t15, but since one cycle has not been reached, the output signal of the status detector 7a remains at a low level. be.

Furthermore, at time t16, when the level of the output signal of the amplifier 3 increases and becomes higher than the output level L3 of the output terminal 6a of the programmable voltage source 6, the same operation as explained at time t9 is performed, and the output terminal 6a of the programmable voltage source 6 performs the same operation as described at time t9. , 6b is set to L2. Set to L3.

At time t17, when the level of the output signal of the amplifier 3 exceeds the output level L2 of the output terminal 6a of the programmable voltage source 6, the output of the comparator 9 changes from low level to high level, and the channel selector 5 outputs a status signal to control the programmable voltage source 6. Output terminals 6a, 6b of voltage source 6
The output level of each is set to L2. As a result, the output signal of the comparator 9 changes from high level to low level.

Furthermore, the output of the amplifier 3 has passed its peak, and at time t18, the output level L2 of the output terminal 6b of the programmable voltage source 6 is reached.
When the voltage becomes smaller, the output level of the comparator lO changes from low level to high level, and as a result, the channel selector 5 outputs a status signal to the control lot 8, and the output level of the output terminals 6a and 6b of the programmable voltage aa6 becomes L2. L, and the output level of the comparator 9 changes from high level to low level.

At time t19, when the level of the output signal of the amplifier 3 becomes smaller than the output level L3 of the output terminal 6b of the programmable voltage source 6, the output of the comparator 10 (7) changes from low level to high level, and the channel selector 5 outputs a status signal. The output levels of the output terminals 6a and 6b of the programmable voltage rA6 are set to L3. Make it L4. As a result, the output signal of the comparator 9 becomes a high level and a low level.

Next, when the output signal of the amplifier 3 passes the zero cross at time t20, the channel selector 5 is reset by the output signal of the waveform shaper 4, and the output level of the output terminals 6a, 6b of the programmable voltage source 6 is changed to L3. I try to set it to L4, but since it has already been set at time 119, the output terminals 6a and 6b of the programmable voltage source 6
Even at time t20, where there is no change, at time t15
The value of one period is calculated by adding the value of the period of half a cycle in , and the value of the error output is calculated based on that period, but since the value of the period is closer to the reference value, the value of the error output is becomes smaller than the value at time t15.

At time t21, when the level of the output signal of the amplifier 3 becomes smaller than the output level of the output terminal 6b of the programmable voltage source 6, the same operation as at time t7 is performed, and the output level of the output terminals 5a and 5b of the programmable voltage source 6 decreases. are respectively L4°L5.

Here, from time tll to time t21, the relationship between the output signal of the amplifier 3 and the output signal of the programmable voltage source 6 becomes a normal relationship as shown in FIG. 2. That is, since the relationship is normal over one cycle of the output signal of the amplifier 3, the output signal of the status detector 7a becomes high level at time t21. When the output signal of the status detector 7a becomes high level, the loop switch 7d measures the period of one cycle of the output signal of the amplifier 3 for each previous zero cross, and calculates the error output based on the period. The drive of the motor 1 by outputting for a period of half a cycle is switched to the drive of the motor 1 by highly accurate control based on the measured values at each comparison point from time L11 to t21. Here, the status detector 7a is the processor 7
If it is configured with software, it is realized by a flowchart as shown in FIG.

In FIG. 5, block 501 determines whether the input signal is a status signal, and if it is not a status signal, the process returns to before block 501. If it is a status signal, the controller 502 determines whether the status signal predicted when the status signal was input last time is equal to the current status signal, and if not, the process goes to block 5.
03, sets the counter value to zero, and returns to before block 501. If the status signals are equal, the process moves to block 504 where the value of the counter is incremented and the process moves to block 505. block 505
Then, it is determined whether or not the counter value has reached 9. If not, the process returns to block 501, and if it is, the status detection signal is set to the NO level and the winter ends.

As described above, when the status detection signal reaches the /% error level, the system shifts to highly accurate control.

The loop switching device 7d switches, based on the output signal of the status detector 7a, whether the control loop is performed based on the value of one cycle for each zero cross or based on the measured value at each comparison point. Therefore, it can be easily realized by software of the processor 7.

A detailed explanation of high-precision control is available in Japanese Patent Application No. 59-21.
Since it is explained in detail in the specification of No. 4544, it will be omitted here.

As described above, according to this embodiment, by controlling the motor based on the period of the output signal of the speed generator when starting the motor,
The rotational speed of the motor is quickly brought close to the set speed to ensure a smooth transition between highly accurate control and control.

Effects of the Invention As described above, the present invention provides a voltage source that generates at least two preset output voltages, and a voltage source that compares the output of the voltage source with the potential of an AC signal having speed information of a rotating body. a comparator that generates an output signal twice or more during a half cycle of the signal; a calculator that calculates an error output from the cycle of the output signal of the comparator and a reference value; and a calculator that calculates an error output based on the error output. a driving means for supplying driving power to the AC signal; and generating a detection signal when the amplitude of the AC signal reaches a larger output potential of the voltage source and the output signal of the comparator is normally output for at least one cycle. status detection means; a servo loop that causes the arithmetic unit to calculate an error output from one cycle of the AC signal and the reference value each time the AC signal passes a zero cross; The motor is characterized by comprising a switch means for switching between a period and a servo loop that causes the arithmetic unit to calculate an error output from the reference value, and the motor rotation speed is quickly brought close to the set speed at the time of startup,
This allows for a smooth transition to high-precision control, which is extremely effective.

[Brief explanation of drawings]

Figure 1 is a block diagram of a servo device in an embodiment of the present invention, Figure 2 is a signal waveform diagram to explain the operation when the system is operating normally, and Figure 3 is when the motor starts. Figure 4 is a signal waveform diagram to explain the operation of the system, Figure 4 is a signal waveform diagram to explain the relationship between the measurement period and output period at startup, and Figure 5 is a signal waveform diagram to explain the status detection operation by the processor. It is a flowchart. 1...Motor, 2...Speed generator, 5
...Channel selector, 6...Programmable voltage source, 7...Processor, 9...
... Comparator, 10 ... Comparator, 11 ... Period detector, 14 ... Digital-to-analog converter, 15 ... Power amplifier. Name of agent Patent attorney Toshio Nakao 1 person from G Figure 2 Figure 3 Figure 4 Figure 5

Claims (3)

[Claims] (1) A voltage source that generates at least two preset output voltages, and a voltage source that compares the output of the voltage source with the potential of an alternating current signal having speed information of a rotating body during a half period of the alternating current signal. a comparator that generates an output signal twice or more; an arithmetic unit that calculates an error output from the cycle of the output signal of the comparator and a reference value; and a drive that supplies drive power to the rotating body based on the error output. and status detection means for generating a detection signal when the amplitude of the alternating current signal reaches the larger output potential of the voltage source and the output signal of the comparator is normally output for at least one cycle;
A servo loop that causes the arithmetic unit to calculate an error output from one cycle of the AC signal and the reference value each time the AC signal passes a zero cross by the detection signal, and a cycle of the output signal of the comparator and the reference value. and a servo loop for causing the arithmetic unit to calculate an error output. (2) Every time the comparator generates an output signal over at least half a period of an AC signal having speed information of a rotating body, the address of the memory means for storing the detection value of the period detector is updated, and the memory means is added to the arithmetic unit. 2. The servo device according to claim 1, further comprising a channel selector that compares the periodic data stored at the corresponding address with a reference value and causes the driving means to output an error output according to the magnitude thereof. (3) Every time the AC signal passes a zero cross until the detection signal of the status detection means is output, the
Select a servo loop that causes the arithmetic unit to calculate an error output based on the cycle and the reference value, and after the detection signal is output, make the arithmetic unit calculate the error output based on the cycle of the output signal of the comparator and the reference value. 2. The servo device according to claim 1, further comprising switch means for selecting a servo loop.