CN1299427C - Semi-frequency driving and loop closing method for micro mechanic sensor - Google Patents

Abstract

The invention relates to a half-frequency drive and a closed-loop method for a micromechanical sensor, belonging to the technical field of control of the micromechanical sensor. In order to overcome the influence of electrical coupling and introduced l/f noise in the existing methods, the present invention discloses a half-frequency driving method for micromechanical sensors, which is characterized in that: two driving electrodes of the electrostatic differential driver Above, apply two pure AC voltages for driving, and the difference between the two voltages is 90°, and its frequency is half of the vibration frequency of the mover. This method can eliminate the electrical coupling from the driving voltage to the sensor detection output, and can reduce the influence of the l/f noise introduced by the driving voltage, and for this driving method, an approximation method in a small range is used to eliminate the voltage to the Non-linear influence of electrostatic force realizes closed-loop control.

Description

Half-frequency drive and closed-loop method for micromechanical sensors

technical field

The invention relates to a drive for an electrostatic micro-mechanical differential driver and a closed-loop method thereof, belonging to the technical field of control of micro-mechanical sensors.

Background technique

At present, the electrostatic actuator commonly used in the field of micromechanics is composed of two parts: the moving plate and the differential drive plate. The drive structure mainly includes two types: parallel plate structure and comb structure. The driving voltage formed by the superposition of DC bias and AC voltage, the driving force generated by this method has the same frequency as the AC component in the driving voltage, so the same frequency component in the driving voltage will be coupled into the detection circuit through space capacitance; On the one hand, when the driving frequency is not too high, the 1/f noise in the driving voltage will directly act on the driving plate to generate a large noise force, which will increase the vibration noise of the plate and deteriorate the driving effect, especially When the electrostatic differential driving method is used to realize the force balance closed loop, the noise effect on the driving force will directly affect the force balance effect, thereby directly affecting the accuracy of the device.

Contents of the invention

In order to overcome the influence of the electric coupling and the 1/f noise introduced in the existing method, the present invention proposes a new driving method for the electrostatic micromechanical differential driver, which can effectively eliminate the AC component caused by the driving voltage The electric coupling brought, and the 1/f noise is moved outside the measurement bandwidth in the frequency domain to achieve the effect of reducing the noise. In addition, when the drive scheme is used to directly drive the device, the present invention proposes a simple The linearization and proportional-integral (PI) correction scheme realizes the driving closed-loop, so as to achieve the purpose of improving the driving performance.

Technical scheme of the present invention is as follows:

The half-frequency driving method for micromechanical sensors is characterized in that: on the two driving electrodes of the electrostatic differential driver in the micromechanical sensor, two AC voltages are applied for driving, and the difference between the two AC voltages is 90 °, whose frequency is half of the vibration frequency of the mover of the electrostatic differential drive.

The AC voltages applied to the two driving electrodes of the electrostatic differential driver are equal in amplitude.

Another technical scheme of the present invention is as follows:

A half-frequency driven closed-loop method for a micromechanical sensor, characterized in that the method comprises the following steps:

1) Using the two detection electrodes of the electrostatic differential driver in the micromechanical sensor to obtain a detection signal reflecting the vibration of the mover of the electrostatic differential driver;

2) After the detection signal is pre-amplified and demodulated once, the amplitude and phase reflecting the structural vibration are obtained through phase-sensitive demodulation;

3) The amplitude and phase are compared with the amplitude setting value A ₀ ² and the phase setting value respectively, and the obtained error values are respectively adjusted by the correction controller, and then multiplied by the amplitude and phase adjustment factors respectively to obtain the corresponding Amplitude and phase control signals;

4) Send the phase control signal into a phase-adjustable sine wave generator for phase shift processing, multiply the amplitude control signal and the output of the sine wave generator for amplitude adjustment, and generate a frequency that is half of the vibration frequency of the mover AC voltage;

5) Pass the AC voltage whose frequency is half of the vibration frequency of the mover through a 90° phase shifter to obtain another driving voltage with a difference of 90° and equal amplitude;

6) The two driving voltages are respectively sent to the two driving electrodes of the electrostatic differential driver to drive the mover to vibrate, so that the electric signal on the detection electrode changes, thereby realizing closed-loop control.

The magnitude adjustment factor in the above scheme is

The phase adjustment factor in the above scheme is 1/2.

The correction controller mentioned above is a proportional-integral controller.

The beneficial effect of the invention is that the driving precision of the sensor can be improved, the noise introduced by the driving voltage can be reduced, and the electrical coupling from the driving signal to the detection output circuit can be reduced or eliminated.

Description of drawings

The present invention will be further described below in conjunction with accompanying drawing.

Fig. 1 is a driving schematic diagram of the present invention.

Figure 2a is the drive voltage noise spectrum.

Figure 2b is a diagram of the effect of frequency shifting of force noise using half-frequency drive.

Figure 3 is a schematic diagram of the closed-loop solution.

In the figure, 2. The left stator of the differential comb drive, 5. The left differential detection electrode, 7. The right differential detection electrode, 9. The right stator of the differential comb drive, 11. The mover, 12. Cosine drive voltage, 13. Sine drive voltage, 14. Differential comb driver, 15. Preamplifier and primary demodulation circuit, 16. Phase loop multiplier, 17. Amplitude loop multiplier, 18. Phase demodulation reference, 19. Amplitude Demodulation Reference, 20. Phase Loop Low Pass Filter, 21. Amplitude Loop Low Pass Filter, 24. Phase Closed Loop Setpoint, 25. Amplitude Closed Loop Setpoint, 28. Phase Closed Loop Controller, 29 . Amplitude closed-loop controller, 32. Phase adjustment factor, 33. Amplitude adjustment factor, 36. Sine wave generator, 37. Multiplier, 38. 90° phase shifter.

Detailed ways

The principle and specific implementation of the present invention will be described in detail below in conjunction with the accompanying drawings.

The principle of the technical solution of the present invention is that a pair of AC voltages with a difference of 90° and no DC bias are applied to the left and right stators of the differential comb drive, and the frequency thereof is the driving force required by the differential comb drive half of the frequency, due to the square relationship between the driving voltage and the driving force, a driving force with a DC component and a frequency multiplied AC component will be generated on the driving plate. At this time, using the principle of differential drive, two differential drive poles The DC components on the board are cancelled, and the remaining AC components are synthesized into the driving force of the required frequency due to the opposite sign, which can drive the mover to vibrate at the frequency of the driving force. Since the frequency of the driving voltage is half of the frequency of the driving force, the frequency of the electrical signal coupled to the output of the device by the driving signal is half the frequency of the desired device motion, so that the detection signal and the coupling signal are separated in the frequency domain, thereby eliminating The effect of electrical coupling. On the other hand, on the noise effect, due to the square relationship between voltage and force, the noise force is modulated to the frequency of the driving voltage, which is half the frequency of the required driving force, thereby shifting the low frequency band of the 1/f noise to this frequency nearby.

In Fig. 1, a pair of cosine drive voltage 12 and sine drive voltage 13 with a difference of 90°, the same frequency and equal voltage amplitude are respectively applied to the left stator 2 of the differential comb drive and the right stator 9 of the differential comb drive , resulting in an electrostatic force generated between the comb teeth on the stator and the comb teeth on the mover, and the electrostatic force drives the mover 11 to vibrate at a frequency twice the frequency of the AC voltage.

Considering the noise model now, let the two voltage expressions be as follows:

${\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; A</span>}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="w"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">w</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; ,</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; A</span>}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; w</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 1</span>}<span\; class="notranslate">\; )</span>$

In equation (1), A is the driving voltage amplitude, ω _c is the driving frequency of the mover, w ₁ and w ₂ are the noise on the cosine driving voltage and sine driving voltage respectively, u _a is the cosine driving voltage, u _{b is} the sine driving Voltage.

As a non-linear energy converter, the electrostatic driver converts the voltage into the driving force output according to the square relationship, so the force generated by the differential electrostatic driver acting on the mover 11 can be expressed as:

${\mathrm{<span\; class="notranslate">\; f</span>}}_{\mathrm{<span\; class="notranslate">\; drv</span>}}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; f</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; u</span>}}_{\mathrm{<span\; class="notranslate">\; b</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; k</span>}}_{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; [</span>{\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; A</span>}{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="w"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">w</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}\mathrm{<span\; class="notranslate">\; cos</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; -</span>\mathrm{<span\; class="notranslate">\; 2</span>}\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="A\; w"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">A</figure-callout></span><figure-callout\; id="2"\; label="A\; w"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">\; </figure-callout>}{\mathrm{<span\; class="notranslate">\; </span>}}_{}{\mathrm{<span\; class="notranslate">w</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}\mathrm{<span\; class="notranslate">\; sin</span>}<span\; class="notranslate">\; (</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&omega;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}\mathrm{<span\; class="notranslate">\; t</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; +</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="w"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">w</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="w"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">w</figure-callout></span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; ]</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 2</span>}<span\; class="notranslate">\; )</span>$

where k _s is a constant related to the structure of the electrostatic actuator.

频率上，如图2a和图2b所示，图2a为加载到驱动电极上的电压噪声谱，图2b为此电压噪声在动子上产生的力噪声谱。这样，1/f噪声中大谱密度段并不直接作用在动子11振动频率上，从而大幅的减小了驱动噪声力，提高了驱动性能。这种方法同目前经常采用的直流叠加交流的驱动方式相比，直流加交流的驱动方式会把噪声直接调制到动子11的振动频率上，这样1/f噪声中大谱密度段直接作用到动子11振动频率上，造成动子11振动噪声变大。In Equation (2), the first term is the main force, the second and third terms are noise driven voltage modulation terms, and the fourth and fifth terms are small squares, which can be ignored, so they act on the mover 11 The main force of is the first term. Therefore, the frequency of the voltage applied to the drive electrodes 2 and 9 is different from the frequency of the force that finally acts on the mover 11, so the electrostatic force acts on the mover 11 so that the frequency of motion produced by it is also different from the frequency of the driving voltage, and finally the left side The frequency of the output electrical signal of the differential detection electrode 5 and the right differential detection electrode 7 is different from the frequency of the driving voltage, so that the electrical coupling from the driving voltage and the real displacement detection output can be separated in the frequency domain to reduce the driving voltage The effect of electrical coupling. On the other hand, analyzing the second and third terms is the influence of force noise caused by the driving voltage. The voltage noise in the driving voltage is generally not white noise but 1/f noise. According to equation (2), the noise voltage is transformed by the electrostatic driver After becoming force noise, it is modulated in the

In terms of frequency, as shown in Figure 2a and Figure 2b, Figure 2a is the voltage noise spectrum loaded on the driving electrode, and Figure 2b is the force noise spectrum generated by this voltage noise on the mover. In this way, the large spectral density segment in the 1/f noise does not directly act on the vibration frequency of the mover 11, thereby greatly reducing the driving noise force and improving the driving performance. This method is compared with the DC superimposed AC driving method that is often used at present. The DC plus AC driving method will directly modulate the noise to the vibration frequency of the mover 11, so that the large spectral density segment of the 1/f noise directly affects the On the vibration frequency of the mover 11, the vibration noise of the mover 11 becomes larger.

Adopting the driving method of the present invention, it can work in two modes of open loop and closed loop.

处的特性，降低了驱动电压到传感器工作频率处的噪声和电耦合，从而提高传感器力平衡性能。If it is used for the closed-loop force balance of the sensor, since the driving force itself is used as a feedback force to balance the force of the sensor, the half-frequency driving mode is an open-loop mode. During specific implementation, one path of sinusoidal drive voltage is directly applied to the stator 2 on the left side of the differential comb-tooth drive, and another cosine drive voltage with a phase difference of 90° from the sinusoidal drive voltage is applied to the right stator of the differential comb-tooth drive 9, the frequency and amplitude of the two voltages are equal, and the movement of the mover reaches a balanced state through the electrostatic force generated. Since the driving method of the present invention has the function of shifting the noise to

The characteristics at the sensor reduce the noise and electrical coupling of the driving voltage to the sensor operating frequency, thereby improving the force balance performance of the sensor.

If it is used to directly drive the sensor to achieve stable vibration, that is, it works in the active drive mode, then a closed-loop working mode should be used to ensure the stability of the vibration amplitude and phase of the sensor. At this time, due to the nonlinear characteristics of the electrostatic driver, the relationship between the driving voltage and the driving force is a square nonlinear relationship, so linearization processing is required when closing the loop. The present invention proposes a simple and feasible closed-loop solution, as shown in FIG. 3 .

In Fig. 3, the detection output of the differential comb driver 14 is sent to the preamplifier and the primary demodulation circuit 15 by the left differential detection electrode 5 and the right differential detection electrode 7 to obtain a signal reflecting the vibration of the mover 11 , carry out phase-sensitive demodulation through phase loop multiplier 16, amplitude loop multiplier 17 and phase demodulation reference 18, amplitude demodulation reference 19, and filter by phase loop low-pass filter 20 and amplitude loop low-pass filter 21, The double frequency component is removed to obtain the phase and amplitude of the vibration of the mover 11 . In order to stabilize the amplitude and phase of the mover 11 , it is necessary to perform feedback control through two closed loops of amplitude and phase.

In the amplitude closed-loop, because the relationship between the driving voltage and the driving force is a square relationship, it is a nonlinear link. In order to make the closed-loop controller easy to implement, it is necessary to carry out appropriate linearization processing. Assuming that the mover 11 needs to be driven to the value A ₀ ² shown in the amplitude closed-loop setting value 25, then within the small range of A ₀ ² , if the detected amplitude is A ² , then:

$\mathrm{<span\; class="notranslate">\; \&Delta;A</span>}<span\; class="notranslate">\; =</span>\mathrm{<span\; class="notranslate">\; A</span>}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}<span\; class="notranslate">\; \&ap;</span>\frac{{\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; \&Delta;</span>}{\mathrm{<span\; class="notranslate">\; A</span>}}^{\mathrm{<span\; class="notranslate">\; 2</span>}}}{\mathrm{<span\; class="notranslate">\; 2</span>}{\mathrm{<span\; class="notranslate">\; A</span>}}_{\mathrm{<span\; class="notranslate">\; 0</span>}}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 3</span>}<span\; class="notranslate">\; )</span>$

Using the approximate linear relationship in equation (3), the corresponding amplitude adjustment factor 33 can be obtained as 1/(2A ₀ ), thereby eliminating the nonlinear influence brought by the square relationship in equation (2), and making the amplitude closed loop easy to realize. The specific implementation process is: the amplitude value is compared with the value A ₀ ² shown in the amplitude closed-loop set value 25 to obtain the amplitude difference value; the amplitude difference value is adjusted through the amplitude closed-loop controller 28, and in the present invention, the amplitude closed-loop controller adopts Proportional-integral (PI) controller, because of its simple form; then according to equation (3), the output of the amplitude closed-loop controller is multiplied by the value 1/(2A ₀ ) shown in the amplitude adjustment factor 33 for correction, through the multiplier 37 and the sinusoidal The output of the wave generator 36 is multiplied to change the amplitude of the output of the sine wave generator to achieve the effect of amplitude control. The transfer function of the amplitude closed-loop controller is as follows:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="K\; p"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">K</figure-callout></span><figure-callout\; id="1"\; label="K\; p"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="1"\; label="K\; i"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">K</figure-callout></span><figure-callout\; id="1"\; label="K\; i"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 4</span>}<span\; class="notranslate">\; )</span>$

Among them, K _p1 is the proportional adjustment coefficient, K _i1 is the integral adjustment coefficient, and s is the Laplace variable.

In the phase closed loop, the relationship from the control voltage phase φ _c to the gyro output phase φ _d is linear:

${\mathrm{<span\; class="notranslate">\; \&phi;</span>}}_{\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; =</span>\frac{\mathrm{<span\; class="notranslate">\; 1</span>}}{\mathrm{<span\; class="notranslate">\; 2</span>}}{\mathrm{<span\; class="notranslate">\; \&phi;</span>}}_{\mathrm{<span\; class="notranslate">\; d</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 5</span>}<span\; class="notranslate">\; )</span>$

From formula (5), it can be obtained that the phase adjustment factor 32 is 1/2, and the specific implementation process of the phase closed loop is: compare the phase value with the phase set value 24 to obtain the phase difference value; the phase difference value is determined by the phase closed loop controller 29 Adjustment, in the present invention, phase closed-loop controller adopts proportional-integral (PI) controller; According to equation (5) with the value 1/2 shown in phase adjustment factor 32, amend, the phase feedback value that obtains is removed to adjust sine wave generator The phase or frequency of 36 changes the vibration phase of the mover 11 to keep the phase stable. The phase closed-loop controller transfer function is as follows:

${\mathrm{<span\; class="notranslate">\; C</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; the\; s</span>}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="K\; p"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">K</figure-callout></span><figure-callout\; id="2"\; label="K\; p"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; <figure-callout\; id="2"\; label="K\; i"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">K</figure-callout></span><figure-callout\; id="2"\; label="K\; i"\; filenames="C0315739100091.png"\; state="\{\{state\}\}">\; </figure-callout>}}_{\mathrm{<span\; class="notranslate">\; </span>}}}{\mathrm{<span\; class="notranslate">\; the\; s</span>}}<span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; -</span><span\; class="notranslate">\; (</span>\mathrm{<span\; class="notranslate">\; 6</span>}<span\; class="notranslate">\; )</span>$

The meanings of the parameters in formula (6) are the same as those in formula (4).

After the output of the sine wave generator 36 is adjusted in amplitude and phase, an AC driving voltage whose frequency is half of the vibration frequency of the mover is obtained. The AC driving voltage is phase-shifted by the 90° phase shifter 38 to obtain another AC driving voltage with a phase difference of 90° and the same amplitude.

Send these two AC drive voltages to the left stator 2 of the differential comb driver and the right stator 9 of the differential comb driver of the electrostatic differential drive respectively, and drive the mover 11 to vibrate, so that the electric signal on the detection electrode changes to achieve closed-loop control.

Claims (6)

1. the half frequency driving method that is used for micro mechanical sensor, it is characterized in that: on two drive electrodes of the electrostatic differential drive in micro mechanical sensor, applying the two-way alternating voltage drives, and described two-way alternating voltage differs 90 °, and its frequency is half of mover vibration frequency of electrostatic differential drive.

2. according to claim 1 half driving method frequently is characterized in that: the alternating voltage amplitude on described two drive electrodes that are added in electrostatic differential drive equates.

3. be used for half of micro mechanical sensor and frequently drive closed-loop policy, it is characterized in that this method comprises the steps:

1) utilize two detecting electrodes of the electrostatic differential drive in the micro mechanical sensor to obtain reflecting the detection signal of the mover vibration of electrostatic differential drive;

2) with after a described detection signal preposition amplification of process and the demodulation, obtain the amplitude and the phase place of reflect structure vibration via phase demodulation;

3) described amplitude and phase place are compared with amplitude set point A02 and phase settings respectively, resulting error amount is adjusted via correcting controller respectively, multiply by amplitude and phase place more respectively and adjusts the factor, obtains corresponding amplitude and phase control signal;

4) sine-wave generator of described phase control signal being sent into adjustable phase carries out phase shift and handles, and the output multiplication of amplitude control signal and sine-wave generator is carried out the amplitude adjustment, produces one tunnel frequency and be half alternating voltage of mover vibration frequency;

5) with said frequencies be half alternating voltage of mover vibration frequency via 90 ° of phase shifters after, obtain differing another road driving voltage that 90 ° and amplitude equate;

6) described two-way driving voltage is sent into two drive electrodes of electrostatic differential drive respectively, driven the mover vibration, the signal of telecommunication on the detecting electrode is changed, thereby realize closed-loop control.

4. according to claim 3 half frequently drives closed-loop policy, it is characterized in that: described amplitude is adjusted the factor and is

5. according to claim 3 half frequently drives closed-loop policy, and it is characterized in that: it is 1/2 that described phase place is adjusted the factor.

6. frequently drive closed-loop policy according to claim 3,4 or 5 described half, it is characterized in that: described correcting controller is a pi controller.

Images