JPS6285684A - Drive circuit for ultrasonic motor - Google Patents

Abstract

PURPOSE:To drive a motor at resonance frequency by simple constitution by setting the frequency of frequency voltage so that a phase difference between a monitor signal from an electrode for monitor and frequency voltage for drive is brought to one on a resonant state at all times. CONSTITUTION:Drive electrodes 1-1, 1-2, an electrode 1-3 for monitor for detecting the resonant state of a stator 1 and a common electrode 1-4 are fitted to a ring-shaped stator 1. Displacement from a predetermined phase difference of a phase difference between an output signal from the electrode 1-3 for monitor and frequency for drive is detected by a phase comparator 12, and an output from the phase comparator 12 is fed to a VCO 5 through a low-pass filter 4, thus determining the frequency of frequency voltage for driving a motor so that a phase difference on a resonant state is brought at all times.

Description

[Detailed Description of the Invention] <Industrial Application Field> The invention is to generate a progressive vibration wave using a 4Q-mechanical energy conversion element in front of an electrostrictive element or a magnetostrictive element, and to drive a rotor with the vibration wave. The present invention relates to an ultrasonic motor drive circuit in which a drive circuit for an ultrasonic motor to be driven and a special control circuit are digitally configured.

<Prior art> Conventionally, circuits that drive ultrasonic motors have been known to operate efficiently due to the fact that the motor rotates efficiently only when a signal at its own resonant frequency is applied. There are n. for example,! . An oscillator with several oscillation frequencies is used, and each frequency is controlled by an ultrasonic motor (SS
It is called M. ), detects the rotational speed at that time, selects and fixes the frequency that gives the largest rotational speed.

Alternatively, instead of giving the oscillation frequency of the v1 rod, the frequency is continuously squeezed, the SSM rotation speed is detected, and the rotation speed is stopped and fixed at the frequency when the rotation speed reaches the peak l.0 2.88M#This SSM drive! A detection terminal is provided to detect ItI fall and a feedback method is adopted in which the signal from the terminal is fed back. By inserting a high filter into the loop of the feedback circuit and increasing the loop gain at the resonant frequency, the resonant frequency of the SSM oscillates due to the feedback effect, and the oscillated signal drives the SSM.

Alternatively, instead of increasing the loop gain near the resonant frequency, at the start of SSM activation, the SSM) j, - is forcibly driven at a frequency near the resonant frequency, and the signal from the detection terminal generated by the drive is fed back. , the frequency near the above resonant frequency is precisely set to the resonant frequency l, and the SSM is driven by a signal of that frequency.

etc. are listed. However, the above-mentioned conventional devices each had the following input points. In the device of type 1 above, that is, one that selects or sweeps the driving frequency, a frequency selection or sweeping circuit is required. Moreover, it requires a device to detect the rotational speed of the SSM, making its configuration complicated.
Since the resonant frequency of an SSM changes depending on the load applied to the SSM or environmental conditions, in order to always obtain efficient rotation, it is necessary to select or sweep the drive frequency for a short period of time and set a continuous drive frequency. I need to do it again.

In addition, in the case of the feedback type mentioned in 2 above, that is, the one that uses the signal from the detection terminal of the SSM, it is possible to obtain a frequency that follows changes in the load or environmental conditions compared to the SSM mentioned in 1, but it requires a high Q filter. Alternatively, an oscillation circuit that forcibly drives the SSM only at the start of activation is required, and both of these require complicated electrical currents, which can lead to increased circuit consumption.

The object of the present invention is to provide a monitor electrode 8 for detecting the malfunction of the 88M, and to transmit a monitor signal of one of the electrodes and a driving frequency to be used to drive the SSM. By detecting the α phase difference with the voltage and determining the frequency of the frequency voltage so that the above phase difference becomes a phase star in the bad case of resonance, an extremely simple configuration can be achieved. The present invention aims to provide a driving circuit for an SSM that drives a trowel and solves the above-mentioned problems.

In the present invention, as a configuration that combines the above objects, a progressive vibration wave is generated on the stator surface by applying frequency voltages having different phases to each electric-mechanical energy conversion element l, and the vibration In an ultrasonic motor that drives a rotor using waves, a monitoring electrode is arranged to detect the driving state of the ultrasonic motor, and a predetermined phase difference between the output signal of the monitoring electrode and the driving frequency voltage is provided. and a frequency determination circuit that determines the frequency of the driving frequency voltage based on the output of the comparison circuit,
The frequency control of the probe wave voltage is such that the phase difference has the predetermined phase difference relationship.

<Example> FIG. 1 is a configuration diagram showing the shape of the electrodes of the stator of the ultrasonic motor according to the present invention. In the figure, reference numeral 1 denotes a ring-shaped stator, and an electrostrictive element having a polarization pattern is arranged on the surface of the stator. Further, reference numerals 1-1 and 1-2 are drive electrodes that apply drive waveforms, to which drive waveforms with a phase difference of 90'' are applied. Reference numeral 1-3 is an electrode for detecting the resonance state of the stator. Further, 1-4 is a common IE electrode, and electrodes 1-1.
1-2.1-3 is connected to the opposite electrode T1.

Similarly, since the structure of the stator itself is well known, a detailed explanation thereof will be omitted, but it is noted that drive waveforms (frequency voltages) with different phases of 90'' are applied to the soldering iron stain. A progressive vibration wave is generated on the surface of the stator.FIG. 2 shows electrodes 1-1 of the stator of the ultrasonic motor shown in FIG.'ii1.
1-2 is a waveform diagram showing the phase relationship between the drive waveform to the detection electrode 1-2 and the output waveform of the detection electrode 1-3 in a resonant state. Figure 2 Ca)
The driving waveform of electrode 1-1.1-2 in FIG.
1.1-2 shows the waveform when reversing the SSM.

Also, in the resonant state during forward and reverse rotation, -a as shown in the figure.
The output from l-3 is 90 from the waveform of Kamekoshi 1-1.
``Pole 1-3 above so that a waveform with a shifted phase relationship is output.
The height has already been set. In this example, as described above.
', since the waveforms of pole 1-1 and pole 1-3 are 90'zn, the position of pole 1-3 is also 90' with respect to the voltage ff11-1.
It is placed 0 degrees off.

FIG. 3 is a circuit diagram showing an embodiment of the SSM drive circuit according to the present invention fζ. 1 in the diagram is! :s1 shows the stator shown in FIG. 1, and 1-1 to 1-4 show each electrode and ε mentioned in FIG. Reference numeral 2 designates a level comparator having one input terminal connected to the detection electrode 1-3 and one input terminal receiving the reference voltage Vm.

12 is a phase comparator (phase comparison circuit) having one input terminal connected to the output of the comparator 2 and the other input connected to the output of an exclusive-or gate (hereinafter referred to as "ex-or") 14, which will be described later. ). The 7 aids converter 12 is, for example, USP42.
No. 91274, etc., are well known, and although a detailed explanation thereof will be omitted, the trowel detects a phase difference between input signals and generates an output only when a phase difference exists.

The block configuration and output characteristics of the nuclear comparator 12 are as shown in Figures 4 and 5.
The input pulse (rising signal) to 411- is human power 48・\
Entered before the rise of Shinsaki? 1. This is the period of rising signal difference, only i and yl are output (-Vcc (high level signal is referred to as H below)), and when the rising signal is input to the upper ml input terminal S, the output is in the oven state. (High impedance state) Becomes self.

Also, the input pulse (AI:J:I/) signal to the input terminal S is inputted earlier than the rising and 4') signal to the input terminal jL, n*=
In this case, the vertical signal sub-surface output is at ground level (referred to as below the grain level).

Also, except for the drawings where the output is H or :ma]j, the state is the same as in the oven state. Therefore, when c1 phase tracking/Js is zero, the output is in the open state 1+)).

4 smoothes the output of comparator 12 with a low bass filter. A two-d voltage control excavator (VC
O) whose input is connected to the output t of the low bar filter 4. 6 is a phase shifter and 6-1 is a vco s
The outputs of the VCO outputs are connected, and two series of signals having a frequency of 1/2 of the vCO output are produced with a phase relationship of 0'' and 90'', and are outputted from the output terminals 6-2 and 6-3, respectively. 7 is an output circuit whose input is connected to the output terminal 6-2 of the shifter 6, and its output is connected to the drive electrode 6 of l-1 through the coil 10.
C is barking a.

9 is ex-or and its human power is 7 fume 6 output 46-3
and the rotation direction are connected to a control terminal t, and its output is connected to a coil 111 via an output circuit 8, which is further connected to drive electrodes 1-2. The coils 10, 11 and the boxes 1-1 and 1-2 form a parallel air circuit. In addition, the above d" force circuit 7.8/ζS
The phase 1 relationship between the input and output 1 is controlled so that they are in the same phase.

Reference numeral 16 denotes a comparator to which electrodes 1-2 and gas-to-human reference voltage V are connected.

14 is an ex-or which inputs the output of the comparator 16 and the output of the inverter 15, and its output is connected to the S input 412 of the phase comparator. Also 15
The inputs of the input terminals are connected to the rotation direction control terminals.

The comparator 2.16 in the above configuration has a structure for reducing the voltage of the polar liquid type to a logic level voltage, as well as the phase comparator 12, the low-pass filter 4. vc05 i Trowel 7 Ace lock loop (hereinafter referred to as PLL) is formed, forming a loop with a large loop gain, and the page feedback effect ζ Trowel input phase difference is '4'.
I will make a crop to make it.

The operation of the embodiment shown in FIG. 3 will be explained. When a radio wave is applied, II-f is applied to each part. In the initial state, there is no input for both the 7 and 8 inputs of the 7 aids comparator 12, so in this state the comparator 12
opens the output:/, which is a lie.

Since the input to the Tamer low-pass filter 4 is not transmitted, the output of the filter 4 is at ground level, and the input I voltage to the VCO 5 is zero. The nucleus v005 is configured to oscillate at the lower limit resonance frequency fo- when the input voltage is zero, and the VaO sends out pulses with a duty of 50 at the frequency fo' as described above. The output pulses of the VOO5 are sent out from the output terminals 6-2.6-3 in pulses with a phase difference of 90'' from the phase shifter 61. The frequency of the output pulse is half the frequency of the output pulse of VOO.The pulse from the output terminal 6-2 of the shifter 6 is passed through the output circuit 7 and the coil 108 to the drive #ttJ electrode 1.
-11 koin sword mouth. The output of the shifter is a square wave (pulse) because the capacitance and resistance between the inductance electrodes 1-1 and 1-4 of the coil IO cause series resonance.
Even so, the drive waveform at electrode 1-1# becomes a sine wave as shown in FIG. Now, assuming that the normal rotation mode is selected, L is input to the 10,000 input of ex-or9, so the input pulse to the output circuit 8 is a pulse whose phase is advanced by 90''. , coil 11, electrode 1-2
．． 1-4, a sine wave whose phase is advanced by 90 degrees with respect to the drive waveform of electrode 1-1 as shown in FIG. 2(a) is generated as shown in FIG.
2 is marked. As a result, sine waves having 9011 phases different from each other are applied to the electrodes 1-1, 1-2, and a progressive vibration wave is generated on the surface of the stator 1, causing friction between the surface of the stator 1 and the The contacting rotor rotates due to the vibration wave, and the SSM is activated.

When vibration waves are generated on the surface of the stator l in this way,
The electrodes 1-37)) generate an output waveform (sine wave) representing an aS shape, which is applied to the comparator 2 and is limited to the voltage of the reference level Vhl logic level. The above electrode 1- is attached to the end R.
It is applied as a pulse having the frequency and phase of a sine wave generated by 31 times.

The driving waveform of one electrode 1-1 is also applied to the comparator 16, similarly limited to a logic level voltage, and applied to the input terminal of the ex-or 14. In the forward rotation mode, the output of the inverter 15 is H, so the eX-0114 acts as an inverter for the output of the comparator 16, and the inverted signal of the comparator 16 is applied to the input terminal S of the comparator 12. Ru.

Therefore, the input signal to the R input terminal of the comparator 12 is a pulse having the phase of the output waveform of the electrodes 1-3, and the input signal to the S input terminal of the comparator 12 has the drive waveform of the electrodes 1-2. The pulse has a phase shifted by 180@.

That is, the output of the comparator 16 is a pulse having the same frequency and phase as the driving waveform of the electrode 1-2, as shown in FIG. 6. The pulse shown in FIG. 6(C) is transmitted to the S input of the comparator 12. On the other hand, a pulse having the same frequency and phase relationship as the output waveform of the electrode 1-S is applied to the R input of the comparator 12. If the pulse applied to the input of the comparator 12 has, for example, the waveform shown in FIG.

Since the input waveforms to R are the same, compantor 12
The output of electrodes 1-1. shows the poor condition of electrodes 1-1.
The drive waveform to 1-2 is maintained as it is.

Figure 6(d) The solid line waveform shown in Figure 6(d) is ex-or14.
It is the same waveform (Fig. 6(C)), and the ex-or14
The output waveform of the comparator 16 is the waveform 116 (b)
) # The waveform is shifted by 180' from this, and the waveform of the comparator 16 is a pulse with the same frequency and phase relationship as the drive waveform of the electrode 1-2, so in the end, the waveform shown in FIG. 6(d) is the same. The solid waveform is pulse shaping for the output waveform of electrode 1-3 in FIG. 2<'a>, which is 90'' out of phase with electrode 1-1.

As mentioned above, from the electrode 1-3, the output waveform (waveform 1-3 in Fig. 2(a)) shifted by 90 degrees from the waveform of 1-1 is outputted from the electrode 1-3. In the above case, the SSM is set to resonate g! @
This indicates that the SSM is driven at the driving frequency at that time, and the output waveform of electrode 1-3 changes from the state shown in Figure 2(a) to the waveform of electrode 1-1. If the phase difference is greater than 90@, the output of comparator 2 will be as shown in Figure 6 (d
) is the waveform shown by the dotted line. Therefore, in this case, the output of the co/parator 12 is the phase difference of the rising signal of the input pulse to the human power fR,S as shown in FIG. 6(e). Ij1 for the drive waveform of electrode 1-1
The time (duty) during which the output of the comparator 12 is high becomes longer as the phase difference with the output waveform of -3 is greater than 90'.

The output of the comparator 12 is inputted to the Vcoi through the low-pass filter 4, and since the V00 generates a pulse with a duty of 50 and a frequency as high as the input voltage, in the above case, the shifter 6 From ≧ 1-1.1
-2j The applied driving frequency becomes higher. SS M
Phase difference with the waveform of cv electrode 1-1.1-3 and gA! @
The relationship with frequency is; π7 as shown in Figure 1.
Since T shows a decreasing tendency, negative feedback is applied in the above Q operation, and the input to the comparator 12, @S, and the input shaping to a are related to the solid lines in (C) and (d) in Figure 6. The equipment will be #.

Therefore, in this case as well, the waveform relationship between the polarizations 1-1 and 1-3 is as shown in FIG. The driving frequency curves are determined to form a resonant river.

In addition, if the relationship between the waveform i of electrode 1-1 and the output waveform of polarization 1-3 is less than 90°, the output of comparator 2 will be the output of ex-or 14 ( Figure 6 (e
) j is 2-1 IAt% in FIG. 6(d). Therefore, in this case, only the phase difference of the rising signal of the above-mentioned waveform (Cd) as shown by the dotted line in FIG. 6(e) is sent out. low pass filter 4
responds to the above signal and reduces its output, so the input pressure to &1XVOO decreases and the output @ wave number of VOO also decreases. Therefore, in this case, electrode 1-1
The frequency in which the phase difference between the waveforms of electrodes 1-3 and 1-3 increases in the 90'' direction is selected for the waveform Jc of n4 poles 1-1 and the waveform Jc of electrode 1-3.
As described above, the output waveform of 3 is in a resonant state shifted by 90' and the wave number is adjusted. Output of parator 2 (electrode 1-
The drive vJ frequency is adjusted so that the phase difference between the output of 3) and the output of ex-or14 (the drive waveform of 4001-2 and the waveform with a phase difference of 180') is zero. Therefore, even if the resonance shape changes, the waveforms of one pole 1-1 and 1-3 will be 90@
The drive frequency that shows a shifted relationship, that is, the strongest resonance frequency, always follows and is driven by 1 at @.In addition, in the reverse mode, the output of the inverter 15 becomes L, so the comparator 12 8 input terminal (if comparator 16
The output of will be input as is, in this case 4
Figure 2 (b) shows 7, ': @ff1 The frequency at which the waveforms 1-1 and 1-3 have an il phase relationship is always the same! This will be the choice.

FIG. 8 is a circuit diagram showing details of the phase comparator 12, low-pass filter 4, V[05, phase 7 cover 6, and output circuits 7 and 8 shown in FIG. 3. Phase comparator 121 (J,; 12-1.12-2
．． 12-13.12-14.12-1512-16 is inverter 12-3.12-8 and gate, 12-
4.12-5.12-6.12-7 is or gate, 1
2-9.12-12 is Noah Gate, 12-11J, 12
-11 is Natgate 12-17 IP channel MO8
FET, 12-18 are N-channel MoS FE
It is T.

Since the companther 12 itself is well known, a detailed explanation thereof will be omitted, or its input/output timing is the same as that described in FIG. This indicates a high, low, or open state.

The low-pass filter 4 is phosphorized with resistors 4-1 and 4-2 and a capacitor 4-3, and the resistor 4-1 is connected to the input/output amount I of the low-pass filter 4, and the resistor 4-2 and the capacitor 4-
3 is connected in series between the output and ground (GNI). In vao s, 5-1 is an operational amplifier, 5-2
, 5-6 , 5-7 , 5-8 .

5-9 is NPN type tiger/distor, 5-3.5-4゜5-
5 HaP NP Type Tiger/Di Xi, 5-10, 5-1
6 is a resistor, 5-11 is a capacitor, 5-14.5-15
The Nant gate 5-17 indicates a constant current source. ￥ OQ 5 human power (1 input at the operational amplifier 5-1, 0 human power of the amplifier 5-1 (1 connected to the emitter of the transistor 5-2 and one of the resistors 5-10, and the resistor 5-1 The other end of 10 is connected to GNP.The above operational amplifier 5-1.) Fujistar 5-2 Resistor 5-1
0, a voltage α current conversion circuit is formed, and a current corresponding to the voltage l input to the amplifier 5-1 flows through the collector 1c of the transistor 5-2.

The collector of transistor 5-2 is transistor 5
-3 collector and base, transistor 5-4.5
The base of the transistor 5-5 is connected to the constant current source 5-171, and the transistors 5-3 and 5-4.5-5 form four current circuits.

Further, the collector of the transistor 5-4 is connected to the collectors of the transistors 5-6 and 5-7 and the collector of the transistor 5-4.
-7, 5-8, and 5-9.The collector of transistor 5-5 is connected to the collector of transistor 5-8, 5-9, and comparator 5-9.
It is connected to the zero power of 12, the e-power of 5-13, and the capacitor 5-11.

The reference voltage V1 is input to the e input of the comparator 5-12.
Also, the e input of 5-13 is the reference voltage V2 (vt > V2)
KaEI] ZIOgft, Koyba L/ -1'-5-
The output of 12 is the input of 10,000 of Nantes gate 5-14,
The other input of the gate 5-14 is the Nantes gate 5-14.
15 swords are connected. Comparator 5-13
The output of 1 is connected to the 10,000 input of gate 5-15, and the other input 1 of gate 5-15 is connected to the output l of gate 5-14.
It's tied together.

The flip-flop is connected to the gate 5-14 and 5-15, and the output of the flip-flop gate 5-15 is connected to the base of the transistor 5-6 via the resistor 5-16.

In the phase shifter 6, 6-4 and 6-5 are D flip-flops, and 6-6 is an inverter. In the output circuit 71, 7-1.7-1', 7-2°7-4.7
-5 is an NPN type transistor, 7-3 is a PNP type transistor, and 7-7 and 7-8 are diodes. First, the output circuit 8 has the same configuration as the output circuit 7.

Each circuit related to the above configuration (low-pass filter 4, vC
The operation of O5, phase shifter 6 + output circuits 7 and 8) will be explained.

The filter 4 is for smoothing the output of the comparator 120), and as a result, an output corresponding to the output condition of the comparator 12 is generated at 1717-4-3.

In detail, as mentioned above, the comparator 120) R2S
When the phase point to the input is zero, that is, the phase difference between the pole 1-1 and the electrode 1-3 is 90°, the output of the co/parator 12 is in an open state, so the low-pass filter 4
The position of the controller 4-3 remains unchanged, but the waveform of the electrode 1-3 is in a phase lead state of 90° compared to the waveform I of the electrode 1-1. When this happens, as described above, the output of the comparator 12 sends out a high signal with a duty corresponding to the phase difference l, and the voltage across the capacitor 4-3 of the filter 4 increases. Conversely, if the waveform of the electrode 1-1 and the waveform of the ζ pole 1-3 lead by a phase less than 90'', the co/parator 12
The output of the output is the low signal (ground level) of the duty whose phase difference l is 6 times higher (!: fj, condenser/server 4-3
The charge level decreases according to the duty cycle.

That is, the filter 4 has the function of converting the output state of the comparator 12 into a voltage and transmitting the converted voltage to vCO.

Since the output of the filter 4 is inputted to the vCO amplifier 5-11, a current corresponding to the output voltage of the filter 4 flows through the resistor 5-10, forming the current at the collector terminal of the transistor 5-2. .

That is, amplifier 5-1. Resistance 5-10. Transistor 5-
2 connects a voltage-to-current conversion circuit that converts the filter output into current. In detail, assuming that the output of the filter 4 is V, a current of the resistor 5-10 is formed at one terminal of the collector of the transistor 5-2. Also, constant current source 5
-17 constant current is 12, this 12 and the above i
Since the synthetic sulfur RI with 1 is supplied from the transistor 5-3, the current of the transistor 5-4 and 5-5 forming the current mirror circuit J3 also becomes the above-mentioned (2).

Assume that the transistor 5-6 is now off and the capacitor 5-11 is in a charged state.

In this case, all of the current flowing through the transistor 5-41 flows to the transistor 5-7, so the transistor 5-7 and the current mirror circuit are connected to the bottom of the groove.
-5-8,5-91 Komosorl, zoa transistor 5
-71 currents flow in the same manner as the current 11f. In this milled rice, the current value flowing through transistor 5-5f and transistor 5-8. A current corresponding to the current value flows out, and the capacitor 5-11 is connected to the transistor 5-57.
The value of the current flowing through the trowel is sieged by the above-mentioned Ii.

This 1 The 4th place of Koteko/De/Ser 5-11 is lowered, below the reference level V, the output of comparator -5-13 becomes L and rl, which constitutes a flip-flop.Nando game-1
-5-15 output H. Therefore, transistor 5
-6 is on, j: rf. 5-Pig Transister 5-6
To become bS O/I, the C transistor 5-41 was used. When all the current flows to the ground, the transistors 5-7, 5-8, and 5-9 are turned off. Therefore, in this case, Torafuji 5 Star 5-5JCt
Yten current, that is, upper Ae = I iC'7: :i
7f,/f-5-11 is subjected to constant light flow t, and the potential of capacitor 5-11 drops to the IL photovoltaic level v1. Comparator 5-12 is inverted at output 7.
:ip, [in order to make it, the output of NAND game) 5-15 is set to L, transistor 5-6 is turned off again, and the above discharge is performed again. Hoai is executed repeatedly.

The photodischarge of the capacitor 5 = 111 times as in two series is carried out in the loop I5!1 of the transistor 5 = -4, and the current 11^ is the 1717 length of the filter -4-
3, that is, the output state of the comparator 12, the speed of the discharge is determined by the pressure of the electrode 1-1.
This is determined by the 4s'L phase difference of the waveform 41-3.

To explain in detail, the waveform of electrode 1-3 with respect to electrode 1-1 is 90
``When the phase is advanced, the output of comparator 12 (because it is open, the capacitor 4-3 is
Since the potential of is held constant, the above +t+
1iiiI is also constant. Therefore, in this case, the charging/discharging operation for the capacitor 5-111 is also at a constant speed, causing the flip-flop to bottom out.
Since the output of 14 also inverts ff1f at the above-mentioned constant speed, the frequency of the output pulse of the flip-frog is kept constant.

The frequency is 2 of the lowest resonant frequency of 55 MIC vs. 1'.
At the lower setting n, which is doubled, the action of the shifter 6 described in J'6 ζ is transmitted to the electrode 1-1.1-2 at the iron resonance frequency, and S The body remains at the same frequency and remains at 0.

Also, for some reason, the two resonance sides are in bad condition, as shown in Figure 7? When the side wave becomes lower than the resonance point and the waveform of 1-3 becomes more than 90" in phase, the output of comparator 12 becomes high. In both cases, the period becomes longer as the phase I fence becomes thicker, and the capacitor 4-3 is charged, and its phase difference becomes larger (L), and the output becomes higher.

Therefore, since both the current value and I are the same, the output frequency of the flip-flop moves in the positive direction. This increases the frequency of the drive waveform to electrodes 1-X and 1-2,
Return the drive waveform to the resonance interval e above j. Therefore, 'l
The difference between the waveforms of the t poles 1-1 and 1-3 (because the l difference also returns to the above-mentioned 90' phase difference, the J gear temporary drive! 1171 is generated.) Also, the inverse 1 drive waveform is Both! 1, Mayuzhou e, higher than the number <4
If the waveform of electrode 1-3 is 90' (U 'f41
The j11 power of Note Comparator 12, which is smaller than the general rule, shows the low and the low! f/J IPii I stand above! The more the i difference increases, the more transparent it becomes. , large), con f.
/Dar-4-3's thrown setting also responds to the two-leg phase difference by 1. (Near 7, to L Me 1-1.1
-2's drive immediately 1 lap, 1 Mr. F5 drive 4i/J lap,
The counterattack returns to the above-mentioned resonance state, and the waveforms to electrodes 1-1 and 1-3 also become the above-mentioned resonance state.

In this way, vCO filters its output pulse frequency to
is determined according to the potential of the capacitor 4-3, and shifts the driving frequency to the electrode ITI, 1-2 to the resonant frequency as described above.

Similarly, even if the resonant frequency itself changes due to environmental changes, etc., the electrodes 1-1, 1-3 are driven at the changed resonant frequency, and the phase difference relationship between electrodes 1-1, 1-3 becomes 90. Since the present invention operates so as to always maintain the above-mentioned phase difference relationship, stable driving follows the changed resonance frequency.

Also, at the initial stage of SSM drive, capacitor 4-
3 is zero, and no current flows through the collector of the transistor 5-2; however, in this case, the current is a constant current value regulated by the constant current source 5-17. 111 cells are charged and discharged. When the constant current source 5-171 stops charging and discharging, the frequency of the seven logic flops is the strongest resonance frequency e, which is the frequency immediately before the frequency that is twice the lower resonance frequency closest to the number. The current value of the constant east current source 5-17 is set so that the current value of the constant east current source 5-17 is set so that the SSM starts driving at this point.

Incidentally, after starting driving at the above-mentioned frequency, no phase difference comparison is performed in the above-described operation, and the frequency is gradually increased to reach the above-mentioned strongest resonance frequency.

As described above, voo5 is in a state where the phase difference of the input signal to the phase co/parator 12 and filter 4 is zero, that is, the waveform to electrodes 1-1 and 1-3 is 906 phase advanced. The output frequency is changed as shown in Figure 5, and the output pulse is input to the shifter 61.

If the shifter 6 still outputs the output pulse of voo 5 as vC
A two-line series of pulses of 0@ and 90@ having half the frequency e and several I of the output pulse of O5 is converted into a drive signal to the drive electrode 1-1.1-2. It has the function of

That is, for example, as the output pulse of vCO now in Fig. 9 Ca)
If the output shown in is output, clip 70
Since the tubes 6-4, 6-5 are configured so that their outputs are inverted at each rising edge signal of the input, the output of the 7-rig flop 6-4 is as shown in FIG. 9(C). In addition, V is applied to the flip-flop 6-5 via an inverter 6-68.
Since the inverted pulse of the CO output is input, the flip 70
The output of the knob 6-5 is as shown in FIG. 9(d). Figure 9 (
C) Each of the 7 lip 7cI knobs 6-4, 6-5 of the 1J mouth shifter that is clear from (d) has a phase of 9011.
A pulse that is a shifted pulse and has a frequency 1/2 of the input pulse is sent out. Therefore, when the frequency of VaO is M1 modified twice the strongest resonant frequency as described above, the flip-flops of the shifter send out pulses at the resonant frequency and with a phase difference of 90@, respectively, to the output circuit 7. 8.

The output circuit sends input pulses to coil 10. The detailed explanation will be omitted, but the pulse via the output circuit is transmitted to the coils 10 and 11, and the coil 1
0,11, electrode 1-1.1-2゜1-4 9 action f trowel A sine wave (second wave) with the same frequency and phase as the pulse
) is applied to electrode 1-1.1-2.
The SM is driven at the above resonant frequency.

<Effects> As described in detail above, in the ultrasonic motor drive circuit according to the present invention tC, the phase difference relationship between the output signal of the 4 monitor poles and the drive cycle voltage 1 always remains in a resonant state. Since the frequency of the driving frequency voltage is determined so as to have a phase difference relationship, the ultrasonic motor can be constructed in an extremely simple manner.
Drive is also related to this resonance state.

Also, in this example, the output from the vCO is directly transmitted to the flip 70x7'6-4+ and the inverter 6-
Is the C7ψ knob flop 6-51 transmitted through 6?
If the output of the flip-flop 6-5 is inverted in synchronization with the falling signal, there is no need to provide the inverter 6-6.

In addition, by frequency-dividing the output pulses of VOOy:)z etc. using a binary counter and using the logic of the dividing peak, we obtain odd-numbered pulse trains and even-numbered pulse trains among the v00 output pulses and flip these pulse trains respectively. 70 Tsubu 6
-4.6-57 How to convey this l Koshidemo shifter 6 to 9
Pulses with different phases of 0° can be obtained.

Also, for every integer multiple of one cycle of the VaO output pulse, 7 rip 7
By inverting the output of the flip-flop 6-4 and inverting the output of the flip-flop 6-5 by the change signal of the vCO output in the half period opposite to the period (which is an integer multiple of 1 or more), τ is also 90'[ It is possible to obtain m different signals, and this time g6vc.

C to take the logic after dividing the output by 8! ! It is something that can be realized.

In addition, in the Kaho example, electrode 1-1 and electrode 1-3 are arranged at positions offset by 9.0 degrees, but WLL123 is placed at an arbitrary position It (for example, at a shifted position r1t) with respect to electrode 1-1. ), the phase difference between the waveforms of electrode 1-1 and electrode 1-3 in the resonance state also acts as a compensator. 1.1
It is sufficient to adjust the driving frequency to −2.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing the polarization shape of the stator of an ultrasonic motor. Figure 2 (a) and (b) are cross-sectional diagrams showing the drive waveform and output waveform of the ultrasonic motor, Figure 2 and 3 are block diagrams showing one embodiment of the ultrasonic motor according to the present invention, and Figure 4
The figure is a block diagram showing the configuration of the comparator 12 shown in FIG. 3, and FIGS. 5(a) and 5(b). (C) is a waveform diagram for explaining the operation of the halator 12, Figure 6 (a), Cb), (C), (
d), (e) are waveform diagrams explaining the operation of the circuit shown in Figure 3, Figure 7 is a characteristic diagram showing the characteristics of the motor, and Figure 8 is a circuit diagram showing the specific +il configuration of the motor shown in Figure 3. , FIGS. 9(a) to 9(d) are waveform diagrams illustrating operation 5 of the shifter in FIG. 8. 5...VCO6...Shifter 12...7 - Izugon Valator Patent Supplier: Canon Co., Ltd. Tomi 5

Claims (1)

[Claims] An ultrasonic motor that generates progressive vibration waves on the surface of a stator by applying frequency voltages with different phases to electric-mechanical energy conversion elements, and drives a rotor with the vibration waves. a comparison circuit disposed with a monitoring electrode for detecting a driving state of the ultrasonic motor and detecting a deviation of a phase difference between an output signal of the monitoring electrode and the driving frequency voltage from a predetermined phase difference; and a frequency determining circuit that determines the frequency of the driving frequency voltage based on the circuit output,
A drive circuit for an ultrasonic motor, characterized in that frequency control is performed on a frequency voltage such that the phase difference has the predetermined phase difference relationship.