WO2022138025A1

WO2022138025A1 - Phase synchronization circuit and control system

Info

Publication number: WO2022138025A1
Application number: PCT/JP2021/044028
Authority: WO
Inventors: 憲二山岡
Original assignee: Ｉ－Ｐｅｘ株式会社
Priority date: 2020-12-25
Filing date: 2021-12-01
Publication date: 2022-06-30
Also published as: DE112021006656T5; CN116601540A; TW202225776A; JP2022102572A

Abstract

In a first phase synchronization circuit (10A), a phase comparison unit (13) receives, as inputs, a detection signal and a driving signal of a first vibration system (20A), and outputs a signal indicating a phase difference between the inputted detection signal and the inputted driving signal. A loop filter (14) smoothes the signal that indicates the phase difference and that has been outputted from the phase comparison unit (13). A voltage control oscillation unit (15) outputs, as an output signal, a signal having a frequency increased in accordance with the magnitude of a signal smoothed by the loop filter (14). A phase shift unit (12) shifts the phase of the detection signal by an adjustable phase shift amount θ. A volume amplifier (16) amplifies the driving signal outputted from the voltage control oscillation unit (15) by an adjustable amplification rate, and outputs the amplified driving signal.

Description

Phase-locked loop and control system

The present invention relates to a phase-locked loop and a control system.

Patent Document 1 discloses a movable reflecting element that two-dimensionally scans the light reflected by the mirror. This movable reflection element includes a fixed frame, an outer actuator, a movable frame, an inner actuator, and a reflection mirror. The outer actuator connecting the fixed frame and the movable frame swings the movable frame with respect to the fixed frame. Further, the inner actuator connecting the movable frame and the reflection mirror swings the reflection mirror at a resonance frequency and a rotation axis different from those of the outer actuator. Two vibration systems consisting of an outer actuator and an inner actuator enable two-dimensional scanning of light by a reflecting mirror.

Japanese Unexamined Patent Publication No. 2005-148459

The outer actuator and the inner actuator may be connected to separate phase-locked loops (PLL). As a result, both vibration systems vibrate in a state of being locked to their own resonance frequencies. However, the resonance frequency of each vibration system changes depending on the surrounding environment such as temperature and atmospheric pressure. Due to this change in resonance frequency, there is a problem that, in some cases, the outer actuator and the inner actuator may move unintentionally in synchronization with each other, and the mirror vibration state cannot be stabilized.

The present invention has been made under the above circumstances, and an object of the present invention is to provide a phase-locked loop and a control system capable of preventing tuning of a vibration system having an inherent resonance frequency.

In order to achieve the above object, the phase-locked loop according to the first aspect of the present invention is
A phase-locked loop that synchronizes the phase of the output signal with the phase of the input signal.
A phase comparison unit that inputs the input signal and the output signal and outputs a signal indicating the phase difference between the input signal and the output signal.
A filter unit that smoothes the signal indicating the phase difference output from the phase comparison unit, and a filter unit.
A voltage control oscillator that outputs a signal whose frequency increases according to the magnitude of the signal smoothed by the filter unit as the output signal.
A phase shift unit that shifts the phase of either the input signal or the output signal input to the phase comparison unit by an adjustable shift amount.
An amplification unit that amplifies and outputs the output signal at an adjustable amplification factor,
To prepare for.

In this case, the phase shift unit shifts the phase of the input signal with respect to the output signal.
It may be that.

Further, the phase shift unit shifts the phase of the output signal with respect to the input signal.
It may be that.

The amplification factor of the amplification unit is adjusted so that the amplitude level of the input signal falls within a certain range.
It may be that.

The control system according to the second aspect of the present invention is
The first phase-locked loop as the phase-locked loop according to the first aspect of the present invention,
A first vibration system that vibrates an output signal output from the first phase-locked loop as a drive signal and outputs a detection signal of the vibration state as an input signal input to the first phase-locked loop.
When the detection signal of the first vibration system is monitored and the synchronized vibration between the first vibration system and another vibration system is detected, the shift amount of the phase shift portion in the first phase synchronization circuit is changed. With the monitoring unit to let
To prepare for.

In this case, the second vibration system as the other vibration system that vibrates according to the input drive signal and outputs the detection signal of the vibration state, and
A second phase-locked loop that synchronizes the phase of the drive signal output to the second vibration system with the phase of the detection signal output from the second vibration system.
Equipped with
The monitoring unit
The detection signal output from the second vibration system is monitored, and the synchronized vibration between the first vibration system and the second vibration system is detected.
It may be that.

The monitoring unit
When the synchronized vibration between the first vibration system and the other vibration system is detected, the shift amount of the phase shift unit is changed so that the frequency locked by the first phase-locked loop becomes low. ,
It may be that.

According to the present invention, since it is provided with a phase shift unit that shifts the phase of either the input signal or the output signal by an adjustable shift amount, it is possible to prevent tuning of a vibration system having a unique resonance frequency. Can be done.

It is a block diagram which shows the structure of the control system which concerns on Embodiment 1 of this invention. It is a signal waveform diagram which shows the phase difference of a detection signal and a drive signal. It is a graph which shows the relationship between the phase difference and the vibration frequency in the 1st vibration system. It is a perspective view which shows the structure of the 1st vibration system. It is a flowchart which shows the processing flow of the adjustment part of FIG. It is a block diagram which shows the structure of the control system which concerns on Embodiment 2 of this invention. It is a block diagram which shows the structure of the control system which concerns on Embodiment 3 of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, the same or equivalent parts are designated by the same reference numerals.

Embodiment 1.
First, Embodiment 1 of the present invention will be described. As shown in FIG. 1, the control system 1 according to the present embodiment controls the first vibration system 20A and the second vibration system 20B. The control system 1 includes a first phase-locked loop 10A and a second phase-locked loop 10B as the phase-locked loop according to the present embodiment. The first phase-locked loop 10A controls the first vibration system 20A, and the second phase-locked loop 10B controls the second vibration system 20B.

The first vibration system 20A and the second vibration system 20B each have an oscillator that inputs a drive signal and vibrates according to the input drive signal. In these oscillators, the vibration state is detected, and a detection signal indicating the detected vibration state is output. The first vibration system 20A and the second vibration system 20B output this detection signal to the outside. The detailed configuration of the first vibration system 20A and the second vibration system 20B will be described later.

The first phase-locked loop 10A outputs a drive signal as an output signal to the first vibration system 20A, and inputs a detection signal output from the first vibration system 20A as an input signal. The first phase synchronization circuit 10A receives the drive signal to the first vibration system 20A based on the phase difference between the drive signal to the first vibration system 20A and the detection signal from the first vibration system 20A. By synchronizing the phase with the phase of the detection signal from the first vibration system 20A, the vibration state of the first vibration system 20A is controlled.

The second phase-locked loop 10B outputs a drive signal as an output signal to the second vibration system 20B, and inputs a detection signal output from the second vibration system 20B as an input signal. The second phase synchronization circuit 10B receives the drive signal to the second vibration system 20B based on the phase difference between the drive signal to the second vibration system 20B and the detection signal from the second vibration system 20B. By synchronizing the phase with the phase of the detection signal from the second vibration system 20B, the vibration state of the first vibration system 20A is controlled.

[First phase-locked loop]
As described above, the first phase-locked loop 10A synchronizes the phase of the drive signal input to the first vibration system 20A, that is, the output signal with the phase of the detection signal of the first vibration system 20A, that is, the input signal. .. In the present embodiment, the first phase-locked loop 10A includes a charge amplifier 11, a phase shift unit 12, a phase comparison unit 13, a loop filter 14 as a filter unit, and a voltage controlled oscillator unit (VCO; Voltage). -Controlled oscillator) 15, an amplifier 16 with a volume, and an adjusting unit 30 are provided.

The charge amplifier 11 is an amplifier circuit that amplifies and outputs the detection signal output from the first vibration system 20A at a set amplification factor. The amplification factor of the charge amplifier 11 may be variable.

The phase shift unit 12 inputs a signal output from the charge amplifier 11, that is, an amplified detection signal output from the first vibration system 20A. The phase shift unit 12 shifts the phase of the input detection signal by an adjustable phase shift amount θ. The phase-shifted signal is input to the phase comparison unit 13. As shown in FIG. 2, when a signal shown by a solid line is input from the charge amplifier 11, the phase shift unit 12 outputs a signal indicated by a dotted line in which the phase of this signal is shifted by a phase shift amount θ. This phase shift amount θ is variable by an external input. Although FIG. 2 shows a case where θ is a positive value, the phase shift amount θ can also take a negative value. CL is the median value of the signal.

Returning to FIG. 1, the phase comparison unit 13 inputs the signal output from the phase shift unit 12, and feeds back the signal output from the voltage control oscillation unit 15 to input. The phase comparison unit 13 outputs a signal indicating the time difference between the rising and falling edges of the two signals, that is, the phase difference. The output signal is a pulse signal including a ripple component.

The loop filter 14 smoothes the pulse signal including the ripple output from the phase comparison unit 13. As the loop filter 14, for example, a lag lead filter is used. The lag lead filter is a low-pass filter composed of two resistance elements and one capacitive element. The characteristics of this lag lead filter determine the transfer characteristics for loop control. As the loop filter 14, a lag filter may be used instead of the lag lead filter. The lag filter is a low-pass filter composed of one resistance element and one capacitive element.

The voltage control oscillator 15 outputs a periodic signal whose frequency increases according to the magnitude of the signal smoothed by the loop filter 14. This periodic signal becomes the drive signal of the first vibration system 20A before being amplified. The voltage control oscillator 15 includes an integral element inside. The value of the input signal is integrated by this integration element, and a detection signal having a higher frequency is output according to the integration result. The detected signal is input to the amplifier 16 with a volume, and is also fed back to the phase comparison unit 13 for input.

The volume-equipped amplifier 16 as an amplification unit amplifies and outputs the drive signal output from the voltage control oscillation unit 15 at an adjustable amplification factor. The output drive signal is input to the first vibration system 20A as a drive signal of the first vibration system 20A.

In the first phase-locked loop 10A, the phase comparison unit 13, the loop filter 14, and the voltage control oscillation unit 15 synchronize the drive signal of the first vibration system 20A with the detection signal of the first vibration system 20A. Is controlled by.

The adjusting unit 30 adjusts the amplification factor of the amplifier 16 with a volume and the phase shift amount θ of the phase shift unit 12. For example, the adjusting unit 30 adjusts the amplification factor of the amplifier 16 with a volume so that the amplitude level of the detection signal of the first vibration system 20A falls within a certain range. A certain range is a range of vibration levels at which the first vibration system 20A exerts its function, the lower limit value is T2, and the upper limit value is T1 (see FIG. 3). If the vibration level is smaller than T2, it becomes difficult to exert the function of the first vibration system 20, and if the vibration level is larger than T1, it can be determined that the tuning vibration has occurred. For example, when the first vibration system 20A scans the laser beam, the vibration level is defined by the scanning range.

When the adjusting unit 30 gradually increases the amplification factor of the amplifier 16 with a volume from 0, the first phase-locked loop 10A oscillates, and the first vibration system 20A vibrates at the oscillation frequency. When the phase shift amount θ of the phase shift unit 12 is 0, the oscillation frequency of the first phase-locked loop 10A matches the resonance frequency of the first vibration system 20A. Such a state is called a so-called "resonance lock state".

Since the voltage control oscillation unit 15 of the first phase-locked loop 10A includes an integrating element, the first vibration occurs when the first vibration system 20A vibrates at the resonance frequency and is in the resonance lock state. A phase difference of about 90 degrees occurs between the detection signal of the system 20A and the drive signal. Conversely, when the phase difference is about 90 degrees, the first vibration system 20A vibrates at the resonance frequency. Here, the reason why it is set to about 90 degrees is that the phase difference between the detection signal and the drive signal is not always 90 degrees due to the circuit characteristics of the loop filter 14 and the like.

The vibration frequency of the first vibration system 20A changes by changing the phase shift amount θ of the phase shift unit 12. As shown in FIG. 3, by increasing or decreasing the phase shift amount θ, it is possible to shift the vibration frequency of the first vibration system 20A from the resonance frequency fr by Δf.

In this control system 1, when the first vibration system 20A and the second vibration system 20B vibrate in synchronization with each other and an unintended large vibration occurs, the adjustment unit 30 adjusts the phase shift amount θ of the phase shift unit 12. change. As a result, the vibration frequency of the first vibration system 20A can be changed, so that the tuning vibration between the first vibration system 20A and the second vibration system 20B can be converged.

[Second phase-locked loop]
The configuration of the second phase-locked loop 10B is the same as the configuration of the first phase-locked loop 10A except that the phase shift unit 12 is not provided. That is, the second phase-locked loop 10B includes a charge amplifier 11, a phase comparison unit 13, a loop filter 14, a voltage control oscillation unit 15, a volume-equipped amplifier 16, and an adjustment unit 30. The second phase-locked loop 10B synchronizes the phase of the output signal, that is, the drive signal of the second vibration system 20B, with the phase of the input signal, that is, the phase of the detection signal of the second vibration system 20B. Under the control of the second phase-locked loop 10B, the second vibration system 20B vibrates at its resonance frequency.

[Monitoring unit]
The monitoring unit 40 monitors the detection signals output from the first vibration system 20A and the second vibration system 20B. The signal to be monitored is a signal amplified by the charge amplifier 11. When the amplitude level of these detected signals becomes larger than the threshold value T1 (see FIG. 3), the monitoring unit 40 states that synchronized vibration has occurred between the first vibration system 20A and the second vibration system 20B. judge. When the monitoring unit 40 determines that the synchronized vibration between the first vibration system 20A and the second vibration system 20B has been detected, the phase shift unit 12 shifts the phase to the adjustment unit 30 of the first phase synchronization circuit 10A. Change the quantity θ. For example, when the monitoring unit 40 detects the synchronized vibration between the first vibration system 20A and the second vibration system 20B, the vibration frequency when locked by the first phase synchronization circuit 10A is lowered. , The phase shift amount θ of the phase shift unit 12 is changed.

The monitoring unit 40 monitors the detection signals output from the first vibration system 20A and the second vibration system 20B, and when the frequency of the detection signals exceeds a predetermined range, the first vibration system 20A is used. It may be determined that the tuning vibration has occurred in the vibration system 20A and the second vibration system 20B. This frequency is calculated from the time series data of the detection signal.

As shown in FIG. 3, the vibration amplitude in the first vibration system 20A decreases depending on the phase shift amount θ of the phase shift unit 12. In this case, the monitoring unit 40 causes the adjusting unit 30 of the first phase-locked loop 10A to increase the gain of the amplifier 16 with a volume so that the amplitude of the drive signal input to the first vibration system 20A becomes large. Here, the value that the phase shift amount θ can take can be, for example, −30 degrees or more and 30 degrees or less. This is because if it exceeds this range, the vibration amplitude in the first vibration system 20A is significantly reduced.

[First vibration system and second vibration system]
Subsequently, the configurations of the first vibration system 20A and the second vibration system 20B will be described. As shown in FIG. 4, the first vibration system 20A and the second vibration system 20B include a fixed frame 50, a movable frame 51, a reflection mirror 52, a first actuator 53, and a second actuator 54. , Consists of.

The fixed frame 50 is a rectangular frame-shaped member, and is fixed to a fixed member (not shown). The movable frame 51 is a rectangular frame-shaped member arranged in the frame of the fixed frame 50. The reflection mirror 52 is arranged in the frame of the movable frame 51. The reflection mirror 52 is a compact and lightweight reflector manufactured by MEMS (Micro Electro Mechanical Systems) technology, that is, a so-called MEMS mirror.

The first actuator 53 is a pair of members provided between the fixed frame 50 and the movable frame 51 on both sides of the movable frame 51 in the X-axis direction. Piezoelectric elements are formed on each of the pair of first actuators 53. Further, the first actuator 53 is provided with a drive electrode 53a for applying a voltage signal to the piezoelectric element. When a drive signal, which is a voltage signal that fluctuates periodically, is applied between the drive electrode 53a and the lower electrode layer provided below the piezoelectric element, the piezoelectric element expands and contracts according to the voltage signal, and the first The actuator 53 bends around the X axis.

In this way, a voltage signal generated from the same signal source is applied to each of the pair of first actuators 53. Since the pair of first actuators 53 are arranged in opposite directions to each other, that is, two-rotationally symmetric, one drive signal is a signal whose phase is inverted with respect to the other drive signal.

The first actuator 53 connects the fixed frame 50 and the point N of the movable frame 51. When the first actuator 53 bends and vibrates around the X axis, the movable frame 51 and the second actuator 54 and the reflection mirror 52 connected to the inside thereof swing around the X axis with respect to the fixed frame 50. Become an oscillator. The first actuator 53 is provided with a detection electrode 53b. The voltage signal generated between the detection electrode 53b and the lower electrode layer is output as a signal indicating the vibration state of the vibrator.

On the other hand, the second actuator 54 is a pair of members between the movable frame 51 and the reflection mirror 52, which are provided on both sides of the reflection mirror 52 in the Y-axis direction. A piezoelectric element is formed in each of the pair of second actuators 54. Further, the second actuator 54 is provided with a drive electrode 54a for applying a voltage signal to the piezoelectric element. When a drive signal, which is a voltage signal that fluctuates periodically, is applied between the drive electrode 54a and the lower electrode layer provided below the piezoelectric element, the piezoelectric element expands and contracts according to the voltage signal, and the second actuator expands and contracts. 54 bends around the Y axis.

In this way, a voltage signal generated from the same input signal is applied to each of the pair of second actuators 54. Since the pair of second actuators 54 are arranged in opposite directions to each other, that is, two-rotationally symmetric, one drive signal is a signal whose phase is inverted with respect to the other drive signal.

The second actuator 54 connects the movable frame 51 and the point M of the reflection mirror 52, and when the second actuator 54 bends and vibrates around the Y axis, the reflection mirror 52 moves the Y axis with respect to the movable frame 51. Swing around. The second actuator 54 is provided with a detection electrode 54b. The voltage signal generated between the detection electrode 54b and the lower electrode layer is output as a signal indicating the vibration state of the vibrator.

In the present embodiment, the vibration system vibrated by the second actuator 54 corresponds to the first vibration system 20A. That is, the drive signal output from the first phase-locked loop 10A is input to the drive electrode 54a of the second actuator 54, and the detection signal output from the detection electrode 54b of the second actuator 54 is the first. Is input to the phase-locked loop 10A of.

Further, in the present embodiment, the vibration system vibrated by the first actuator 53 corresponds to the second vibration system 20B. That is, the drive signal output from the second phase-locked loop 10B is input to the drive electrode 53a of the first actuator 53, and the detection signal output from the detection electrode 53b of the first actuator 53 is the second. Is input to the phase-locked loop 10B of.

The reflection mirror 52 swings in the biaxial direction by the first vibration system 20A and the second vibration system 20B. By irradiating the swinging reflection mirror 52 with the laser beam, the reflected laser beam can be scanned two-dimensionally. The control system 1 that scans the laser beam two-dimensionally is used for a laser printer, an optical scanner, a projector, and the like.

The vibration frequency of the first vibration system 20A, that is, the resonance frequency is, for example, 20 kHz to 30 kHz, and the resonance frequency of the second vibration system 20B is, for example, about 100 Hz. Further, the first vibration system 20A horizontally scans the laser beam, and the second vibration system 20B vertically scans the laser beam. This makes it possible to project, for example, a two-dimensional image with a laser beam. The resonance frequencies of the first vibration system 20A and the second vibration system 20B can be adjusted by changing the shape, thickness or material of the first vibration system 20A and the second vibration system 20B.

When a tuned vibration occurs between the first vibration system 20A and the second vibration system 20B, the vibration states of the first vibration system 20A and the second vibration system 20B are disturbed, and two-dimensional scanning of the reflected laser beam is performed. Becomes difficult. The monitoring unit 40 determines the tuning based on the detection signals output from the first vibration system 20A and the second vibration system 20B, and when the tuning is performed, the phase of the first phase-locked loop 10A. The phase shift amount θ of the shift unit 12 is changed. As a result, the vibration frequency of the first vibration system 20A is changed, and the tuning vibration between the first vibration system 20A and the second vibration system 20B is suppressed.

The configuration of the first vibration system 20A and the second vibration system 20B described above is an example, and is not limited thereto. For example, the fixed frame 50 and the movable frame 51 may have a circular shape or other shape instead of a rectangular frame shape. The reflection mirror 52 may also have a rectangular shape or other shape instead of a circular shape. As the first and

second actuators

53 and 54, various shapes such as a meander shape can be applied.

Next, the operation of the control system 1 according to the present embodiment will be described. In the present embodiment, the operation of the control system 1 is controlled by the monitoring unit 40. FIG. 5 shows a flowchart showing the processing of the adjusting unit.

As shown in FIG. 5, first, the monitoring unit 40 causes the adjusting unit 30 of the first phase-locked loop 10A and the second phase-locked loop 10B to increase the amplification factor of the volume-equipped amplifier 16 from 0 (step S1). ). As a result, the first phase-locked loop 10A and the second phase-locked loop 10B oscillate, and the first vibration system 20A and the second vibration system 20B start to vibrate. When the phase difference between the detection signal and the drive signal reaches about 90 degrees, both the first vibration system 20A and the second vibration system 20B vibrate at the resonance frequency. Here, the phase difference between the detection signal and the drive signal when vibrating at the resonance frequency is 90 degrees.

Next, the monitoring unit 40 determines whether or not to end the process (step S2). The end determination is determined by the instruction signal input to the monitoring unit 40. Here, the process proceeds to step S3 without ending (step S2: No).

Next, the monitoring unit 40 monitors the detection signals of the first vibration system 20A and the second vibration system 20B, and the amplitude level of the detection signals of the first vibration system 20A and the second vibration system 20B is the threshold value T1. It is determined whether or not the value exceeds (see FIG. 3) (step S3). The threshold value T1 is a threshold value for determining the occurrence of synchronized vibration in the first vibration system 20A and the second vibration system 20B. As described above, in this process, the threshold value of the frequency may be determined instead of the amplitude level.

If the amplitude of the detection signal exceeds the threshold value T1 (step S3; Yes), the monitoring unit 40 causes the adjustment unit 30 of the first phase-locked loop 10A to change the phase shift amount θ of the phase shift unit 12 (step S4). ).

After the end of step S4 or when the amplitude of the detection signal is equal to or less than the threshold value T1 (step S3; No), the monitoring unit 40 indicates that the amplitude level of the detection signal of the first vibration system 20A is less than the threshold value T2 (see FIG. 3). It is determined whether or not there is (step S5). The threshold value T2 is the minimum value required for the vibration level of the detection signal of the first vibration system 20A. If the amplitude level of the detection signal of the first vibration system 20A is less than the threshold value T2 (step S5; Yes), the monitoring unit 40 uses the adjusting unit 30 of the first phase-locked loop 10A to the amplifier 16 with a volume. The amplification factor is increased (step S6).

When the amplitude level of the detection signal of the first vibration system 20A is equal to or higher than the threshold value T2 (step S5; No) or after the end of step S6, the monitoring unit 40 determines the end of processing (step S2). If it does not end (step S2; No), the monitoring unit 40 performs processing in the flow of steps S3 → S4 → S5, step S3 → S5, or step S3 → S5 → S6. Such a series of processes are repeated, and the monitoring unit 40 suppresses the synchronized vibration between the first vibration system 20A and the second vibration system 20B, while suppressing the first vibration system 20A and the second vibration system 20B. Control is performed so that the amplitude level of the detection signal of is within a certain range.

When the process is terminated (step S2; Yes), the monitoring unit 40 reduces the amplification factor of the amplifier 16 with a volume to 0 (step S7), and the vibration of the first vibration system 20A and the second vibration system 20B. End control.

Embodiment 2.
Next, Embodiment 2 of the present invention will be described. As shown in FIG. 6, in the control system 1 according to the present embodiment, the first phase-locked loop 10A, the second phase-locked loop 10B, the monitoring unit 40, the first vibration system 20A, and the first vibration system 20A are used. The point that the vibration system 20B of 2 is provided is the same as the configuration of the control system 1 according to the first embodiment.

In the first phase-locked loop 10A according to the first embodiment, the phase shift unit 12 shifts the phase of the detected signal output and amplified from the first vibration system 20A. On the other hand, in the first phase-locked loop 10A according to the present embodiment, the phase shift unit 12 is connected to the signal output from the voltage control oscillation unit 15, that is, the first vibration system 20A before being amplified. Shifts the phase of the input drive signal. A signal whose phase is shifted by the phase shift amount θ is input to the phase comparison unit 13.

As described above, in the present embodiment, the phase of the drive signal of the first vibration system 20A, that is, the output signal is shifted with respect to the phase of the detection signal, that is, the input signal. Even in this way, it is possible to change the vibration frequency of the first vibration system 20A and suppress the synchronized vibration between the first vibration system 20A and the second vibration system 20B.

In the present embodiment, the processing of the monitoring unit 40 is the same as the processing shown in FIG. The monitoring unit 40 keeps the amplitude level of the detection signals of the first vibration system 20A and the second vibration system 20B within a certain range while suppressing the synchronized vibration between the first vibration system 20A and the second vibration system 20B. Control to fit.

Embodiment 3.
Next, Embodiment 3 of the present invention will be described. As shown in FIG. 7, the control system 1 according to the present embodiment is different from the control system 1 according to the above embodiment in that the adjustment unit 30 is not provided. In the present embodiment, the phase shift unit 12 has a function corresponding to the adjustment unit 30, and the volume-equipped amplifier 16 has a function corresponding to the adjustment unit 30. The monitoring unit 40 monitors the detection signals of the vibration states of the first vibration system 20A and the second vibration system 20B, and detects the synchronized vibration between the first vibration system 20A and the second vibration system 20B. , The phase shift unit 12 is made to change the phase shift amount θ. Further, the monitoring unit 40 monitors the detection signals of the first vibration system 20A and the second vibration system 20B, and the volume-equipped amplitude amplifier 16 monitors the detection signals of the first vibration system 20A and the second vibration system 20B. Adjust the amplitude level. Further, when the monitoring unit 40 detects the tuning vibration, the phase shift unit 12 causes the phase shift unit 12 to change the phase shift amount θ. Therefore, the control system 1 according to the present embodiment can adjust the amplification factor of the amplification unit of the amplifier 16 with a volume and the phase shift amount θ of the phase shift unit 12 as in the control system 1 according to the above embodiment. Is.

The control system 1 according to the above-described first to third embodiments controls the vibration state of the second vibration system 20B by the second phase-locked loop 10B. However, it is not limited to this. It is not necessary to include the second phase-locked loop 10B. When the phase is not synchronized, the second vibration system 20B is driven non-resonantly by inputting a periodic signal clearly deviating from the resonance frequency. At the time of non-resonance, it is not possible to drive efficiently with a small signal level as in the case of resonance, so it is necessary to input a large signal level, but there is an advantage that it can be driven with a fixed frequency without considering the influence of resonance due to temperature or the like.

The non-resonant drive circuit includes a charge amplifier 11 and an amplifier 16 with a volume. By changing their amplification factors, the vibration of the second vibration system 20B is controlled. The signal level of the drive signal is adjusted by an amplifier 16 with a volume or the like.

For example, in a projector, in two-dimensional scanning, the number of scanning lines in the vertical direction is determined by the standard, so it is necessary to fix the period in the vertical direction. If the drive in the vertical direction is a resonance lock by a phase-locked loop, the period will fluctuate due to the influence of temperature and the like, so it is desirable to control the vibration in the vertical direction by non-resonant drive. As the drive signal, it is desirable to use a stable periodic signal synchronized with the crystal clock, for example, a signal generated by a microcomputer operating on the crystal clock.

As described in detail above, according to the above embodiment, the phase of either the detection signal or the drive signal of the first vibration system 20A input to the phase comparison unit 13 can be adjusted by a shift amount. It is provided with a phase shift unit 12 for shifting with. As a result, the vibration frequency of the first vibration system 20A can be changed, so that tuning of the vibration system having a unique resonance frequency can be prevented.

Here, as in the first embodiment, the phase shift unit 12 may shift the phase of the drive signal to the first vibration system 20A with respect to the detection signal, or the second embodiment. As described above, the phase shift unit 12 may shift the phase of the detection signal of the first vibration system 20A with respect to the drive signal.

According to the above embodiment, the monitoring unit 40 has a volume so that the amplitude level of the detection signal output from the first vibration system 20A and the second vibration system 20B is within a certain range in the adjustment unit 30. The amplification factor of the attached amplifier 16 was adjusted. By doing so, it is possible to prevent a decrease in the amplitude of the first vibration system 20A due to the phase shift amount θ given by the phase shift unit 12.

Further, the control system 1 according to the above embodiment monitors the detection signals of the vibration states of the first vibration system 20A and the second vibration system 20B, and the first vibration system 20A and the second vibration system 20B When the tuning vibration of the above is detected, the monitoring unit 40 for changing the phase shift amount θ of the phase shift unit 12 of the first phase synchronization circuit 10A is provided. By doing so, the phase shift amount θ can be made variable, and the synchronized vibration between the first vibration system 20A and the second vibration system 20B can be reliably prevented.

Further, the phase shift amount θ in the phase shift unit 12 may be fixed. If the phase shift amount θ that prevents the synchronized vibration between the first vibration system 20A and the second vibration system 20B is known in advance, even if the phase shift amount θ in the phase shift unit 12 is fixed, the first vibration It is possible to prevent the tuning vibration between the system 20A and the second vibration system 20B.

However, since the resonance frequency generally changes depending on the surrounding environment such as temperature and humidity, and the vibration conditions such as the mass of the first vibration system 20A and the second vibration system 20B, the phase shift amount θ is variable. It is desirable that the phase shift unit 12 is provided.

Further, in the above embodiment, when the monitoring unit 40 detects the synchronized vibration between the first vibration system 20A and the second vibration system 20B, the frequency locked by the first phase-locked loop 10A is low. The phase shift amount θ of the phase shift unit 12 is changed so as to be. Generally, if the amplitude level of the first vibration system 20A of the amplifier 16 with a volume is increased, the resonance frequency of the first vibration system 20A also increases. Therefore, if the phase shift amount θ is adjusted in the direction in which the vibration frequency of the first vibration system 20A becomes lower, the synchronized vibration between the first vibration system 20A and the second vibration system 20B is surely prevented. be able to.

In the above embodiment, the adjusting unit 30 individually adjusts the amplification factor of the amplifier 16 with a volume and the phase shift amount θ of the phase shift unit 12. However, it is not limited to this. The resonance frequency of the first vibration system 20A changes according to the amplification factor of the amplifier 16 with a volume. Specifically, as the amplification factor of the amplifier 16 with volume increases, the resonance frequency of the first vibration system 20A changes toward higher. Utilizing such a relationship, the adjusting unit 30 may be able to adjust the amplification factor of the amplifier 16 with a volume and the phase shift amount θ of the phase shift unit 12 at one time via one parameter. ..

In the above embodiment, the vibration states of the first vibration system 20A and the second vibration system 20B are controlled. However, the present invention is not limited to this. The second vibration system 20B does not have to be controlled by the second phase-locked loop 10B. Even in this case, the phase shift unit 12 of the first phase-locked loop 10A can suppress the synchronized vibration between the first vibration system 20A and the second vibration system 20B.

Further, in the above embodiment, among the first vibration system 20A and the second vibration system 20B, the detection signal is obtained for the first phase synchronization circuit 10A that controls the first vibration system 20A having a high vibration frequency. And the phase of the drive signal is to be shifted. This is because it is easier to suppress the entrainment in this way. However, the present invention is not limited to this. The phase shift unit 12 may be provided in the second phase-locked loop 10B that controls the second vibration system 20B having a low vibration frequency.

Further, in the above embodiment, a case where vibration control of two vibration systems having their own unique resonance frequencies, that is, the first vibration system 20A and the second vibration system 20B, has been described. However, the present invention is not limited to this. It can also be applied to a system having three or more vibration systems having a unique resonance frequency. For example, the present invention can be applied to suppress tuning vibrations in a system that swings a reflective mirror around the X, Y, and Z axes.

When suppressing the synchronized vibration of the three vibration systems, it is sufficient that the phase-locked loop that controls at least two of the three vibration systems includes the phase shift unit 12. This also applies when the number of vibration systems is four or more.

In the above embodiment, the control system controls the MEMS mirror as a reflection mirror that scans the laser beam two-dimensionally. However, the present invention is not limited to this. The reflection mirror may be a larger polygon mirror, a galvano mirror, or the like. It can also be applied to a control system that controls a reflection mirror that scans ultrasonic waves two-dimensionally. In addition, this control system 1 can be applied as long as it includes a plurality of vibration systems, each of which has a unique resonance frequency.

Also, what is controlled is not limited to reflection mirrors and the like. The present invention can be applied to any vibration system that vibrates by a drive signal. For example, the present invention can be applied even when controlling a plurality of independent vibration systems arranged in the vicinity of each other, although they do not have a common component. In particular, it is suitable for a system having a plurality of vibration systems having the same resonance frequency.

In the control system 1 according to the above embodiment, the amplification factor of the charge amplifier 11 may be adjustable.

In the above embodiment, the monitoring unit 40 monitors both the detection signal of the first vibration system 20A and the detection signal of the second vibration system 20B, but only monitors one of the detection signals. But it may be.

The present invention allows various embodiments and modifications without departing from the broad spirit and scope of the present invention. Further, the above-described embodiment is for explaining the present invention, and does not limit the scope of the present invention. That is, the scope of the present invention is shown not by the embodiment but by the claims. Then, various modifications made within the scope of the claims and within the scope of the equivalent invention are considered to be within the scope of the present invention.

It should be noted that the present application claims priority based on Japanese Patent Application No. 2020-217385 filed on December 25, 2020, and the specification of Japanese Patent Application No. 2020-217385 is described in this specification. , Claims, the entire drawing shall be taken as a reference.

The present invention can be applied to control the vibration state of a vibration system having a unique resonance frequency.

1 Control system, 10A 1st phase synchronization circuit, 10B 2nd phase synchronization circuit, 11 charge amplifier, 12 phase shift section, 13 phase comparison section, 14 loop filter, 15 voltage control oscillator section (VCO), 16 volume With amplifier, 20A first vibration system, 20B second vibration system, 30 adjustment unit, 40 monitoring unit, 50 fixed frame, 51 movable frame, 52 reflection mirror, 53 first actuator, 53a drive electrode, 53b detection electrode , 54 second actuator, 54a drive electrode, 54b detection electrode

Claims

A phase-locked loop that synchronizes the phase of the output signal with the phase of the input signal.
A phase comparison unit that inputs the input signal and the output signal and outputs a signal indicating the phase difference between the input signal and the output signal.
A filter unit that smoothes the signal indicating the phase difference output from the phase comparison unit, and a filter unit.
A voltage control oscillator that outputs a signal whose frequency increases according to the magnitude of the signal smoothed by the filter unit as the output signal.
A phase shift unit that shifts the phase of either the input signal or the output signal input to the phase comparison unit by an adjustable shift amount.
An amplification unit that amplifies and outputs the output signal at an adjustable amplification factor,
A phase-locked loop.
The phase shift unit shifts the phase of the input signal with respect to the output signal.
The phase-locked loop according to claim 1.
The phase shift unit shifts the phase of the output signal with respect to the input signal.
The phase-locked loop according to claim 1.
The amplification factor of the amplification unit is adjusted so that the amplitude level of the input signal falls within a certain range.
The phase-locked loop according to any one of claims 1 to 3.
The first phase-locked loop as the phase-locked loop according to any one of claims 1 to 4.
A first vibration system that vibrates an output signal output from the first phase-locked loop as a drive signal and outputs a detection signal of the vibration state as an input signal input to the first phase-locked loop.
When the detection signal of the first vibration system is monitored and the synchronized vibration between the first vibration system and another vibration system is detected, the shift amount of the phase shift portion in the first phase synchronization circuit is changed. With the monitoring unit to let
Control system with.
A second vibration system as the other vibration system that vibrates according to the input drive signal and outputs a detection signal of the vibration state, and
A second phase-locked loop that synchronizes the phase of the drive signal output to the second vibration system with the phase of the detection signal output from the second vibration system.
Equipped with
The monitoring unit
The detection signal output from the second vibration system is monitored, and the synchronized vibration between the first vibration system and the second vibration system is detected.
The control system according to claim 5.
The monitoring unit
When the synchronized vibration between the first vibration system and the other vibration system is detected, the shift amount of the phase shift unit is changed so that the frequency locked by the first phase-locked loop becomes low. ,
The control system according to claim 5 or 6.