JPH0449875A - Driving controller for surge stepping motor - Google Patents

Abstract

PURPOSE:To step-drive a rotor according to a phase pattern by applying the driving voltage of frequency equal to the resonance frequency of oscillating elements and a stator, to the oscillating elements, in order with a specified phase pattern. CONSTITUTION:By a control circuit 103, the oscillation generating signal of the same frequency as the resonance frequency of an oscillating body 107, and signal for inverting the phase are processed, and the control signal of a specified phase pattern is fed. By a driver 104, the control signal is amplified, and the output of driving voltage is generated. The oscillating body 107 is fitted on a stator 2, and is composed of a plurality of oscillating elements 108. The driving voltage from the driver 104 is applied to the oscillating elements 108, and on the elements 108, deflection oscillation is formed, and a rotor is driven in a step state. As a result, according to a specified phase pattern, the rotor can be step-driven.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The second invention relates to a drive control device for a wave step motor that enables step drive using ultrasonic vibrations, and particularly to a drive circuit thereof.

[Prior art and problems to be solved by the invention] A conventional ultrasonic motor using ultrasonic vibration is disclosed in Japanese Patent Application Laid-open No. 511
-93477 Publication, Special Publication No. 59-37671,
JP-A-59-122H5, JP-A-80-5147
Various methods have been proposed and implemented, as disclosed in Publication No. 8 and the like. All of these ultrasonic motors rotate or move continuously as long as a driving voltage is applied.

Therefore, in the conventional ultrasonic motor, feedback control is necessary to control its rotational speed, stop position, or rotational speed, and a control circuit for this is essential. Therefore, there was a problem that the control system had to become complicated.

In order to solve these problems, the present applicant filed Japanese Patent Application No. 1-278 dated October 20, 1999 for a "wave step motor" that operates as a so-called stepping motor.
It was proposed as No. 082. However, in the second application, details regarding the drive control system of this "wave step motor" were not sufficiently disclosed.

The present invention has been made in view of the above situation, and an object of the present invention is to provide a drive control device for a wave step motor having a drive circuit suitable for the motor according to the above proposal.

[Means for Solving the Problems] A drive control device for a wave step motor according to the present invention includes:
A plurality of oscillators are arranged in succession, and a stator is vibrated by the oscillators, and a number of protrusions corresponding to the number of nodes generated when the oscillators vibrate are provided. In a wave step motor having a rotor disposed in contact with the stator, positive and negative power supply voltages are supplied, and a driving voltage of a frequency equal to the resonant frequency of the vibrator and the stator is applied to one terminal of the vibrator at a predetermined level. It has a drive circuit that sequentially applies voltage in a phase pattern, and the other terminals of the vibrators are commonly grounded. A filter circuit is provided on the output side of the drive circuit, and a sine wave voltage having a frequency equal to the resonant frequency of the vibrator and the stator is applied to the vibrator as a drive voltage.

Further, in the drive control device for a wave step motor according to the present invention, in place of the above-mentioned drive circuit, a drive circuit is supplied with either the positive or negative power supply voltage and sequentially applies the drive voltage in a predetermined phase pattern. has.

Further, in the drive control device for a wave step motor according to the present invention, instead of the above-mentioned drive circuit, either the positive or negative power supply voltage is supplied, and the drive voltage is applied to one terminal of the vibrator at a predetermined phase. It has a drive circuit that sequentially applies voltage in a pattern, and the other terminals of the vibrators are commonly connected.

[For production]

In this invention, positive and negative drive voltages are sequentially applied to the vibrator in a predetermined phase pattern, and the rotor performs a step operation in accordance with the phase pattern. When a filter circuit is provided, a sine wave voltage having a frequency equal to the resonant frequency of the vibrator is applied as a driving voltage, and the vibrator vibrates efficiently.

Further, in the present invention, when either the positive or negative power supply voltage is supplied, the drive voltage of one polarity is sequentially applied in a predetermined phase pattern.

In addition, in this invention, when either the positive or negative power supply voltage is supplied and the other terminals of the vibrators are connected in common, the vibrators are connected in series according to the phase pattern of the drive voltage at that time. Connected.

[Example] Prior to a detailed explanation of the present invention, an outline of a wave step motor will first be clarified.

FIG. 5 is a block diagram showing an overview of a wave step motor and its drive system. In the figure, 10 ports are crystal oscillators, 101 is a crystal oscillation circuit, and 102 is a frequency division circuit that divides the frequency of the output signal from the crystal oscillation circuit. 103 is a control circuit which receives an oscillation signal from an oscillation circuit 105 that oscillates at the same frequency as the resonant frequency of the vibrating body 107 and a signal from a phase inversion circuit 106 that inverts the phase of the oscillation signal from the oscillation circuit 105. A control signal is sent out by processing the A driver 104 amplifies a drive control signal from the control circuit 103 and applies a drive voltage to the vibrating body 107.

Reference numeral 108 denotes a vibrator, and an example is shown in which the vibrating body 107 consists of four vibrators, each of which is configured to vibrate independently.

Further, in the figure, A is the output signal of the oscillation circuit 105, and A is the output signal of the phase inversion circuit 106, which has an opposite phase to the output signal A. C is the output signal of the frequency divider circuit 102, which is a control signal for controlling the output signal A and the anti-phase port, and 2 is the output signal of the control circuit 103, which is the output signal of the vibrator 107.
This is a drive control signal for driving.

FIGS. 6(a) to 6(e) are explanatory diagrams showing the operating principle of a wave step motor, and the explanation will be based on an example in which a piezoelectric element is used as a vibrating body.

FIG. 6(a) shows the state of the vibration mode of a predetermined phase. As shown in the figure, the rotor 1 has protrusions 1a, lb, l.
A piezoelectric element 3 is attached to the stator 2 on the opposite side of the rotor 1, and the projections 1a and lc are in partial contact with the stator 2. This piezoelectric element 3 consists of four vibrators and is classified into two types, A and B, and A and B deform in opposite phases to each other.

N indicates a vibration mode node of the stator 2.

FIG. 6(b) shows a state of vibration mode having an opposite phase to that of FIG. 6(a). Here, the protrusions 1 b and 1 d are in partial contact with the stator 2 .

In Fig. 6(a) and (b), node N of stator 2
The portions of the rotor 1 that are in contact with the stator 2, such as the convex portions 1a and lb, which are located at an interval equal to or several times the interval , are each subjected to a force 10.11 in the direction shown by the arrow. At this time, the force 10.11 has a component force in the direction of the node N from the convex part in the vibration mode, so the stator 1 is 10a.

It receives a force in the direction of 11b, that is, in the direction of the nearby node N.

Figures 6(c) and 6(d) show cases in which the positional relationship between the stator 2 and rotor 1 is different from that in Figures 6(a) and 6(b), and in this case, the rotor 1 is moved by the force 12.13 It receives forces 12a, 18a (in the opposite direction to 10a, llb) in the direction of , that is, in the direction of the node N located at the nearer position.

FIG. 6(e) is a superimposed view of FIGS. 6(a) to (d). In either case, it can be seen that the convex portions 1a to 1d of the rotor 1 move toward the NN of the stator 2, so that they are positioned at the node N thereof. Therefore, if the position of the node N moves in steps, the rotor 1 moves in steps and operates as a step motor.

FIG. 7 is a cross-sectional view showing an example of a structure in which a wave step motor is applied to a rotary type motor, and FIG. 8 is a plan view of the rotor-stator portion of FIG. 7. In the figure, 4 is a base plate that fixes the stator 2 with screws 6, 5 is a gear train bridge that freely guides the rotor 1, 7 is a pinion that extracts the rotational force of the rotor 1, and 8 is a voltage applied to the electrode pattern 3a of the piezoelectric element. This is the lead wire that applies the voltage. In this embodiment, the protrusions 1a to 1d are partially provided on the rotor 1 in its thickness direction.

FIG. 9 is a plan view showing another configuration example when the wave step motor is applied to a rotary motor. In this embodiment, the stator 2 is provided with protrusions 2a in the thickness direction around the entire circumference, and the rotor Convex portions a to d are provided to protrude in the diametrical direction of 1.

In the configuration examples shown in FIGS. 7 and 9, examples are shown in which the rotor and the stator 2 are in contact with each other at four locations (four convex portions).

In addition, the vibrating body 3 consists of 12 vibrators as shown by broken lines, and for the sake of explanation later, A, B, C, p, .
The symbols 100 and C are attached, and drive voltages of the same phase are applied to equal symbols. In addition, symbols ``■'' to ``■'' are sequentially attached to positions that become nodes of vibration modes. In addition, in this example, mN
are generated at four locations, and there are 122 locations around the entire circumference where nodes can be formed.

FIG. 10 is an explanatory diagram showing how the above-mentioned wave step motor is driven in steps, and the symbols correspond to those in FIG. 9, and are expanded into a linear type for convenience of explanation. The broken line indicates the shape of the vibration mode, and for convenience, the state of the phase of the voltage applied to each vibrator at that moment is indicated by a minus sign.

In the vibration mode (2), A, B, and C are paired with λ, ■, and σ, and they vibrate with a phase shift of 180' from each other, so that the convex portion aSbSc of the rotor 1.

d is in the position shown.

In the vibration mode of ■, B, C, A and 100, C, A are paired, and in the vibration mode of ■, C, A, B and C, A, 100 are paired,
The vibration modes (1) to (2) are repeated in sequence, and the rotor 1 moves stepwise. In the rotating type shown in Figure 9, 1
Makes one rotation in two steps.

Furthermore, if steps are taken in the opposite direction to the vibration modes shown in the figures, for example, if the vibration mode is switched to obtain the vibration mode of ■, the rotor 1 will move in the direction opposite to that in the above case. Move to.

As is clear from the above description of FIG. 10, it is understood that this wave step motor can also be constructed as a linear near motor.

FIG. 11 is a phase timing chart for creating the vibration mode shown in FIG. 10. For example, when creating the vibration mode of ■, A, B, and C have positive (+) phases,
Then, a driving voltage with a negative (=) phase is applied. These controls are performed by the control circuit 103 described above. If the output signal A from the oscillation circuit 05 is to have a positive (+) phase, the output signal port of the oscillation circuit 1 (15) is Negative (-)
The switching is performed at the timing of the frequency divider circuit 1020 control signal C (dotted chain line in FIG. 11). In addition, six types of drive control device 2 are required: A, B, C, λ, and 100, but since A and A, B and 100, and C and σ have opposite relationships, the direction of polarization must be determined. If reversed, the same operation can be obtained with the three types.

FIG. 12 shows a timing chart of the driving voltages applied to the vibrating elements A and B. For example, in the vibration mode (■), a driving voltage with an opposite phase is applied to the vibrator A, and in the vibration mode (■),
In the vibration mode, driving voltages of opposite phases are applied to the vibrator and B. The drive voltage in each vibration mode at this time is a sine wave, and its frequency is made to match the resonant frequency of the stator to which the vibrating body is attached.

As is clear from the above description, by appropriately switching the phase of the drive voltage applied to each vibrator, step drive in 12 divisions per revolution can be realized.

FIG. 13 is a plan view showing another configuration example of the wave step motor. The vibrating body 3 has four vibrators A, 76,.

The rotor 1 and the stator 2 are made of 100 BSs, and are in contact with each other at two contact points a and b, the number of WnN is two, and the possible positions of nodes N are eight.

FIG. 14 is an explanatory diagram showing the vibration mode and the positional relationship between contact parts a and b, FIG. 15 is a timing chart of the phase of the drive voltage to create the vibration mode of FIG. 14, and FIG. It is a timing chart of the drive voltage applied to A and B. In FIG. 15, "+" and "-" indicate a state of opposite phase, and "0" indicates a state in which no driving voltage is applied. Therefore, in this embodiment, a wave step motor with 8 divided steps (1/2 step) per rotation can be realized.

In addition, in the above-mentioned embodiment, a representative example of a rotary type was shown, but if the rotor can be moved to a driving node and the way of driving the vibrating elements can be changed sequentially to move the rotor in steps, it is possible to move the rotor in steps. There are no restrictions on the specific structure, shape of vibration mode, type or configuration of the vibrator, etc. Further, the oscillation circuit 105 may use the output of the crystal oscillation circuit 101, or may be a self-excited oscillation circuit that detects the vibration of the resonator 107 and resonates under optimal conditions. There is no problem even if it is not based on signals from 10 vibrators.

In addition, after the wave step motor moves to the desired position, there is friction between the rotor and the stator.
Even if the drive is stopped, the stopped position is maintained.

Now that the outline of the wave step motor has been clarified through the above explanation, its drive control system will be explained next.

FIG. 1 is a circuit diagram of a drive control device for a wave step motor according to an embodiment of the present invention. The control circuit 103
/6 frequency divider circuit 109, shift register 110, inverter 121. , 122 , 123 , 124 , 125
.

126, AND gate 131 , 132 , 133 ,
134.

1.35, 136 and orgate 141, 142
, 143. The phase inversion circuit 106 is composed of an inverter 127. The driver 104 has buffers J5J, 152, 153, 154,
155 and 156, each buffer is supplied with positive and negative power supply voltages, respectively, and outputs a driving voltage that oscillates between the positive and negative electrodes. The vibrating body 107 is attached to the stator 2 and includes a plurality of vibrators 10
It consists of 8. Then, the plurality of oscillators 10
One terminal of 8 is the corresponding buffer 151.152°1
Drive voltages from 53, 154, 155, and 156 are applied, and the other terminals are commonly grounded.

In this embodiment, a wave step motor having a vibration mode of 2λ with 12 division steps per rotation is operated at 1 step (3
This is an example of a circuit when driving 0').

Although omitted in FIG. 1, the crystal oscillation circuit 101 and frequency divider circuit 102 that are omitted in FIG. etc. are used.

FIG. 2 is a timing chart showing the operation of the drive control device having the above configuration. When the IHz control signal φ1 from the frequency divider circuit 102 in FIG. is supplied to register 10. And shift register 10
17 GHz signals φ1/6a, φ1/6b, φ1/6c whose phase shifts by 1 second and reverses by 3 seconds.
outputs. And the signal φ1/6a is an AND gate]
31 and inverted by the inverter 21, the signal 201 is input to the AND gate 132. The AND gate 131 receives the output signal (2) from the phase inversion circuit 106, and the AND gate 132 receives the oscillation signal φ from the oscillation circuit 105. As a result, an output signal 204 consisting of the AND of the signal φ1/6a and the output signal 1 is obtained from the AND gate 181. and gate 13
2 to the inverted signal 201 of the signal φ1/8a and the oscillation signal φ
An output signal 205 is obtained from the logical product. These output signals 204 and 205 are output to the OR gate 14.
1 to the buffer 151 and also to the buffer 154 via the inverter 124.

Operation based on signals φ1/6b and φ1/6c is also φ1/6.
Basically the same as case a, each inverted signal 20
2, 203 are processed in the same way as in the case of φ1/6a described above, and the drive control signals input to the buffers 152, 153, 155, and 156 have a phase of 1 with respect to the drive control signals of oscillators A and A, respectively. Six types of drive voltages are output from the driver 04, and each buffer has a drive voltage that oscillates between the positive voltage and the negative voltage at the frequency of the oscillation signal φ according to the input drive control signal. is applied to the vibrator 108, and instantaneously drives the vibrator 108 two at a time. Therefore, three vibrators 108 are driven in the same phase or in opposite phase, and a vibration with a deflection of 2λ is formed.
This vibration drives the rotor 1 in a step-like manner.

Note that the drive voltage is ideally a sine wave, and in that case, for example, a filter circuit (not shown) that passes the frequency component of the oscillation signal φ is provided after the output of the driver 04, and the drive voltage is changed. Make it a sine wave.

FIG. 3 is a circuit diagram of a drive control device for a wave step motor according to another embodiment of the present invention. This embodiment differs from the above embodiments in that only the positive voltage is supplied to the driver 104, and the negative electrode is grounded instead of being supplied.

Therefore, only the positive voltage is applied to the vibrator 10B, and the output is halved compared to the above embodiment, but it is suitable for no-load or light loads, and It has the advantage of requiring only one power source.

In the embodiment shown in FIG. 3, a negative power supply voltage may be used instead of the positive power supply voltage.

FIG. 4 is a circuit diagram of a drive control device for a wave step motor according to another embodiment of the present invention. This embodiment has a driver 104 and a vibrator 10B in relation to the above embodiments.
The difference is that it is not grounded. Therefore, the vibrators A and X, for example, are connected in series, and the driving voltage applied to each vibrator is 1/2 that of the above embodiment.

Therefore, the output is reduced to 1/2 compared to the embodiment shown in FIG. 3, but the structure is simplified since there is no need to ground the vibrator 108. In particular, it is difficult to form a grounding structure when the stator 2, the ground plate 4 shown in FIG. becomes easier. In the embodiment shown in FIG. 4 as well, the negative power supply voltage may be used instead of the positive power supply voltage.

[Effects of the Invention] As described above, according to the present invention, since the positive and negative drive voltages are sequentially applied to the vibrator in a predetermined phase pattern, the rotor can be driven in steps according to the phase pattern. Furthermore, since a filter circuit is provided to apply a sine wave voltage having a frequency equal to the resonant frequency to the vibrator as a driving voltage, the vibrator vibrates efficiently.

Further, according to the present invention, since either the positive or negative power source voltage is supplied and the drive voltage of one polarity is applied sequentially in a predetermined phase pattern, a single power source can be used. The configuration is simple.

Further, according to the present invention, the power supply voltage of either the positive electrode or the negative electrode is supplied to one terminal of the vibrator, and the other terminal of the vibrator is connected in common, so that the vibrator is connected to the grounded structure. This has the advantage of simplifying the configuration.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram of a drive control device for a wave step motor according to one embodiment of the present invention, FIG. 2 is a timing chart showing its operation, and FIGS. 3 and 4 are diagrams showing other embodiments of the present invention. FIG. 2 is a circuit diagram of a drive control device for such a wave step motor. Figure 5 is a block diagram showing an overview of the wave step motor.
Figure 6 (a), (b), (c), (d)
, (e) is an explanatory diagram of the operation of a wave step motor, Fig. 7 is a sectional view showing an example of the configuration of a wave step motor, Fig. 8 is a plan view of the stator/rotor part of the tJ7 diagram, and Fig. 9 is a diagram of the wave step motor. Fig. 10 is an explanatory diagram showing the vibration mode and step drive state; Fig. 11 is a plan view showing another configuration example;
The figure is a timing chart of the driving voltage phase, Figure 12 is a timing chart of the driving voltage, Figure 13 is a plan view showing another configuration example of a wave step motor, and Figure 14 shows the vibration mode and positional relationship of the contact part. 15 is a timing chart of the driving voltage phase, and FIG. 16 is a timing chart of the driving voltage. DESCRIPTION OF SYMBOLS 1... Rotor, 2... Stator, 3... Piezoelectric element, 103... Control circuit, 104... Driver, 10
5... Oscillation circuit, 106... Phase inversion circuit, 107
... Vibrating body, 108... Vibrator.

Claims (4)

[Claims] (1) A plurality of vibrators are arranged in succession, a stator is vibrated by the vibrators, and a number of convex portions is provided corresponding to the number of nodes generated when the vibrators vibrate, In a drive control device for a wave step motor having a rotor in which the convex portion is arranged in contact with the stator, positive and negative power supply voltages are supplied, and a drive voltage having a frequency equal to the resonant frequency of the vibrator and the stator. What is claimed is: 1. A drive control device for a wave step motor, comprising: a drive circuit that sequentially applies the following signals to one terminal of the vibrator in a predetermined phase pattern, and the other terminal of the vibrator is commonly grounded. (2) The drive control device for a wave step motor according to claim 1, further comprising a filter circuit that outputs a sine wave voltage having a frequency equal to the resonant frequency of the vibrator and the stator on the output side of the drive circuit. (3) A claim characterized in that, in place of the drive circuit according to claim 1, a drive circuit is provided which is supplied with either a positive or negative power supply voltage and sequentially applies the drive voltage in a predetermined phase pattern. 1. The drive control device for a wave step motor according to 1. (4) A plurality of vibrators are arranged in succession, a stator is vibrated by the vibrators, and a number of protrusions corresponding to the number of nodes generated when the vibrators vibrate are provided; In an ultrasonic motor having a rotor in which the convex portion is arranged so as to be in contact with the stator, either a positive electrode or a negative electrode power supply voltage is supplied, and a driving voltage having a frequency equal to the resonant frequency of the vibrator and the stator is supplied. A drive control device for a wave step motor, comprising a drive circuit that sequentially applies voltage to one terminal of the vibrator in a predetermined phase pattern, and the other terminal of the vibrator is commonly connected.