CN103776436B - The rotor type micro gyroscope detection device of time-division frequency division multiplexing - Google Patents

Abstract

The invention discloses a rotor-type micro-gyroscope detection device with time-division frequency-division multiplexing, which belongs to the field of MEMS devices. The invention solves the problems existing in two existing differential capacitance detection methods. The invention includes a rotor-type micro-gyro sensitive unit, a charge-voltage conversion unit, a phase-sensitive demodulation unit, an analog-to-digital conversion unit, a signal processing unit, a digital-to-analog conversion unit, a first low-high-voltage conversion unit, a second low-high-voltage conversion unit and two Time division frequency division multiplexing unit; the carrier excitation signal V ⁺ , V ^‑ and the feedback control signal of the two time division frequency division multiplexing units are multiplexed and loaded to the rotor type micro gyro sensitive unit; the equivalent gyro signal of the rotor type micro gyro sensitive unit The output end is connected with the input end of the phase-sensitive demodulation unit; the demodulation signal output detection signal of the phase-sensitive demodulation unit; the demodulation signal output end of the phase-sensitive demodulation unit is connected with the analog signal input end of the analog-to-digital conversion unit; then Perform analog-to-digital conversion, signal processing, digital-to-analog conversion, and low-voltage to high-voltage conversion, and feed back to two time-division frequency-division multiplexing units.

Description

Time-division frequency-division multiplexing rotor-type micro-gyroscope detection device

technical field

The invention relates to a micro-gyroscope detection technology and belongs to the field of MEMS devices.

Background technique

For the detection circuit of high-precision micro-sensors, especially the rotor-type micro-gyro sensor, the angular velocity signal detection is realized based on the rotor deflection angle method, and the displacement signal is picked up by using the differential capacitance detection method. Compared with other detection methods, this method has technical advantages such as high detection accuracy (<10 ^-14 meters), high linearity (<10 ^-4 ), and non-contact measurement. At present, there are mainly two differential capacitance detection methods. The first one is to use the middle electrode excitation (single frequency) method to detect multiple sets of capacitance changes at the same time. However, due to the high resistance characteristics of the charge amplifier, it is easy to form interference with the same frequency detection, and there is channel coupling. phenomenon, so such methods are rarely used. The second method is widely used. Each vector direction capacitance (4 pairs of differential capacitance) plus multi-frequency excitation (frequency division multiplexing) method can detect multiple sets of capacitance changes at the same time. However, due to the non-ideal characteristics of electronic devices (gain bandwidth Product, slew rate, settling time and other parameters) make the phase-sensitive demodulation aliasing phenomenon exist in the frequency division multiplexing method, which leads to the cross-sensitivity problem of each vector capacitance detection. In order to avoid the above problems, it is necessary to increase the frequency difference of each excitation signal and add a high-order band-pass filter. However, the sensitivity and zero position of the micro-gyroscope will drift due to the phase temperature drift of the filter. At the same time, since the rotor of the rotor-type micro-gyro sensor is suspended in the cavity, when the rotor is disturbed by the outside world, it cannot be connected directly. Closed-loop feedback control is required to ensure that the rotor works at zero position.

Contents of the invention

The object of the present invention is to solve the problems existing in the two existing differential capacitance detection methods, and to provide a rotor-type micro-gyroscope detection device with time division and frequency division multiplexing.

The time-division-frequency-division multiplexing rotor-type micro-gyroscope detection device of the present invention includes a rotor-type micro-gyroscope sensitive unit, a charge-voltage conversion unit, a phase-sensitive demodulation unit, an analog-to-digital conversion unit, a signal processing unit, a digital-to-analog conversion unit, A first low-voltage conversion unit, a second low-voltage conversion unit, a first time-division frequency-division multiplexing unit, and a second time-division frequency-division multiplexing unit;

The carrier excitation signal V ⁺ and the feedback control signal of the first time-division frequency-division multiplexing unit are multiplexed and loaded to the first group of multiplexed signal input terminals of the rotor-type micro-gyroscope sensitive unit;

The carrier excitation signal V- of the second time ^- division frequency-division multiplexing unit is multiplexed with the feedback control signal and loaded to the second group of multiplexing signal input terminals of the rotor-type micro-gyroscope sensitive unit;

The equivalent gyro signal output end of the rotor type micro gyro sensitive unit is connected with the input end of the phase sensitive demodulation unit;

The demodulation signal output end of the phase-sensitive demodulation unit is used as the detection signal output end of the rotor type micro-gyroscope detection device with time division and frequency division multiplexing;

The demodulation signal output end of the phase-sensitive demodulation unit is connected with the analog signal input end of the analog-to-digital conversion unit;

The digital signal output end of the analog-to-digital conversion unit is connected to the input end of the signal processing unit;

The output end of the signal processing unit is connected with the digital signal input end of the digital-to-analog conversion unit;

The analog signal output end of the digital-to-analog conversion unit is simultaneously connected to the low-voltage signal input end of the first low-high-voltage conversion unit and the low-voltage signal input end of the second low-high-voltage conversion unit;

The feedback signal control signal output terminal of the first low-voltage conversion unit is connected to the feedback control signal input terminal of the first time division frequency division multiplexing unit;

The feedback control signal output end of the second low-voltage conversion unit is connected to the feedback control signal input end of the second time division frequency division multiplexing unit;

The phase difference between the carrier excitation signal V ⁺ and the carrier excitation signal V ^- is 180°.

The advantages of the present invention: in order to realize the detection of the radial deflection angle of the rotor, the present invention adopts 8 excitation electrodes and the rotor together to form 4 pairs of differential capacitors and 1 pair of charge pickup electrodes and the rotor to form 1 pair of pickup capacitors to realize the detection of capacitance changes. Thus, the dual-axis (X-axis, Y-axis) angular velocity signal pickup of the rotor gyroscope is realized indirectly. The invention adopts time division multiplexing + modulation and demodulation technology to solve the aliasing phenomenon of multi-frequency phase-sensitive demodulation signals, and completely eliminates the cross-sensitivity of each axial detection because only a single-frequency excitation signal is used. The excitation signal is time-divisionally connected to four pairs of differential capacitors through the φ ₁ -φ ₄ timing switches in the two time division frequency division multiplexing units. The capacitance change is detected and amplified by the charge amplifier, and then passed through the φ ₁ in the phase sensitive demodulation unit - φ ₄ timing switches for phase-sensitive demodulation, thereby indirectly realizing the pick-up of the radial deflection angle of the rotor. The position control of the rotor in the gyroscope is realized by the principle of electrostatic force servo. In order to minimize the amplitude of the servo voltage and maximize the detection capacitance, the method of sharing the capacitance detection electrode and the electrostatic force servo control electrode is adopted, that is, RC isolation and frequency division multiplexing are used to realize capacitance detection and electrostatic force under the same electrode. servo. Among them, the electrostatic force feedback voltage signal completes the biaxial angular velocity vector calculation, static compensation and dynamic distribution of the voltage vector through the digital signal processor.

Description of drawings

Fig. 1 is the functional block diagram of the rotor type micro-gyroscope detection device of time division frequency division multiplexing of the present invention;

Fig. 2 is a circuit diagram of a phase-sensitive demodulation unit.

detailed description

Specific embodiment one: the present embodiment is described below in conjunction with Fig. 1, the rotor-type micro-gyroscope detection device of time-division frequency-division multiplexing described in the present embodiment, it comprises rotor-type micro-gyroscope sensitive unit 100, charge-voltage conversion unit 101, phase-sensitive solution Tuning unit 102, analog-to-digital conversion unit 103, signal processing unit 104, digital-to-analog conversion unit 105, first low-voltage conversion unit 106, second low-voltage conversion unit 107, first time division frequency division multiplexing unit 108 and second Time division frequency division multiplexing unit 109;

The carrier excitation signal V ⁺ and the feedback control signal of the first time-division frequency-division multiplexing unit 108 are multiplexed and loaded to the first group of multiplexed signal input terminals of the rotor-type micro-gyroscope sensing unit 100;

The carrier excitation signal V of the second time ^- division frequency-division multiplexing unit 109 is multiplexed with the feedback control signal and loaded to the second group of multiplexing signal input terminals of the rotor-type micro-gyroscope sensing unit 100;

The equivalent gyro signal output end of the rotor type micro gyro sensitive unit 100 is connected with the input end of the phase sensitive demodulation unit 102:

The demodulation signal output end of the phase-sensitive demodulation unit 102 is used as the detection signal output end of the rotor type micro-gyroscope detection device with time division frequency division multiplexing;

The demodulation signal output end of the phase-sensitive demodulation unit 102 is connected with the analog signal input end of the analog-to-digital conversion unit 103;

The digital signal output end of the analog-to-digital conversion unit 103 is connected to the input end of the signal processing unit 104;

The output end of the signal processing unit 104 is connected with the digital signal input end of the digital-to-analog conversion unit 105;

The analog signal output end of the digital-to-analog conversion unit 105 is simultaneously connected with the low-voltage signal input end of the first low-voltage high-voltage conversion unit 106 and the low-voltage signal input end of the second low-high-voltage conversion unit 107;

The output terminal of the feedback signal control signal of the first low-voltage conversion unit 106 is connected to the input terminal of the feedback control signal of the first time division frequency division multiplexing unit 108;

The feedback control signal output end of the second low-voltage high-voltage conversion unit 107 is connected to the feedback control signal input end of the second time division frequency division multiplexing unit 109;

The phase difference between the carrier excitation signal V ⁺ and the carrier excitation signal V ^- is 180°.

Embodiment 2: This embodiment will further explain Embodiment 1. The rotor-type micro-gyroscope sensitive unit 100 includes four pairs of differential capacitors and a pair of pickup capacitors. The four pairs of differential capacitors are C1, C5; C2, C6; C3, C7 ; With C4, C8; the pair of pickup capacitors are C9, C10; pickup capacitors C9 and C10 are connected in parallel;

The multiplexing signals loaded by the differential capacitors C1, C2, C3 and C4 are the carrier excitation signal V ⁺ and the feedback control signal; the multiplexing signals loaded by the differential capacitors C5, C6, C7 and C8 are the carrier excitation signal V ^- and the feedback control signal;

The differential capacitor C1 multiplexes and loads the carrier excitation signal V ⁺ and the feedback control signal V+ΔV _x ;

The differential capacitor C2 multiplexes and loads the carrier excitation signal V ⁺ and the feedback control signal V+ΔV _y ;

The differential capacitor C3 multiplexes and loads the carrier excitation signal V ⁺ and the feedback control signal V-ΔV _x ;

The differential capacitor C4 multiplexes and loads the carrier excitation signal V ⁺ and the feedback control signal V-ΔV _y ;

The differential capacitor C5 multiplexes and loads the carrier excitation signal V ^- and the feedback control signal V-ΔV _x ;

The differential capacitor C6 multiplexes and loads the carrier excitation signal V ^- and the feedback control signal V-ΔV _y ;

The differential capacitor C7 multiplexes and loads the carrier excitation signal V ^- and the feedback control signal V+ΔV _x ;

The differential capacitor C8 multiplexes and loads the carrier excitation signal V ^- and the feedback control signal V+ΔV _y ;

The output terminals of the four pairs of differential capacitors are simultaneously connected to the input terminals of a pair of parallel pickup capacitors, and the output terminals of the parallel pair of pickup capacitors serve as the equivalent gyro signal output terminals of the rotor-type micro-gyro sensing unit 100 .

Among them: V is the equivalent voltage value of the carrier excitation signal V ⁺ , V ^- , ΔV _x is the relative voltage value in the X-axis direction to bring the rotor back to the equilibrium position; ΔV _y is in the Y-axis direction, The relative voltage value required to bring the rotor back to the equilibrium position.

Specific embodiment three: this embodiment will further explain embodiment one. The first time division frequency division multiplexing unit 108 and the second time division frequency division multiplexing unit 109 have the same structure, and are both composed of a switch network and a summation unit. The switch network described above is a group of time switches φ ₁ , φ ₂ , φ ₃ , φ ₄ ; it is controlled by a time-sharing switch and loaded with a multiplexing signal through a summation unit;

The time-division switches φ ₁ , φ ₂ , φ ₃ , and φ ₄ in the first time-division frequency-division multiplexing unit 108 respectively control the loading of differential capacitors C1, C2, C3, and C4;

The time-division switches φ ₁ , φ ₂ , φ ₃ , φ ₄ in the second time-division-frequency-division multiplexing unit 109 respectively control the loading of differential capacitors C5, C6, C7 and C8.

Specific embodiment four: the present embodiment is described below in conjunction with Fig. 2, and this embodiment is further described to embodiment one, phase-sensitive demodulation unit 102 is made up of a group of φ ₁ -φ ₄ timing switches and four-way phase-sensitive demodulator, The phase-sensitive demodulation unit 102 demodulates the signal output by the charge-to-voltage conversion unit 101, and outputs four shift signals.

The phase-sensitive demodulator restores the amplified AC voltage signal to a DC voltage signal, where f ₀ is the frequency of the carrier excitation signals V ⁺ and V ^- .

working principle:

Time-division switches φ ₁ -φ ₄ in the first time-division frequency-division multiplexing unit 108 and the second time-division frequency-division multiplexing unit 109 together with time-division switches φ ₁ -φ ₄ in the phase-sensitive demodulation unit 102 have realized the signal time-division multiplexing; in the first time-division frequency-division multiplexing unit 108 and the second time-division frequency-division multiplexing unit 109, the excitation signal V ⁺ , V- is combined with the first low ^- voltage conversion unit 106 and the second time-division frequency division multiplexing unit 109 through the summation unit Σ The feedback control signals output by the two low-voltage and high-voltage conversion units 107 are multiplexed together to implement frequency division multiplexing of signals.

The multiplexing signal is loaded on the differential capacitors C1-C8 by the time-division switches 108 and 109 φ ₁ -φ ₄ , and the equivalent gyro signal v ₁ is output by the parallel pickup capacitors C9 and C10, and the equivalent gyro signal is detected by and amplified output voltage signal v ₂ ; phase-sensitive demodulation unit 102 demodulates voltage signal v ₂ to output four-way displacement signals S ₁ , S ₂ , S ₃ , S ₄ ; analog-to-digital conversion unit 103 converts four-way displacement signals S ₁ , S ₂ , S ₃ , S ₄ are converted into corresponding bit stream signals d ₁ , d ₂ , d ₃ , d ₄ ; the signal processing unit 104 performs bit stream signal d ₁ , d ₂ , d ₃ , d ₄ processing, complete the biaxial angular velocity vector calculation, static compensation and voltage vector dynamic distribution, and output the processed four-way digital bit stream signals d ₁₁ , d ₁₂ , d ₁₃ , d ₁₄ ; the digital-to-analog conversion unit 105 converts the digital bit stream signal d ₁₁ , d ₁₂ , d ₁₃ , d ₁₄ are converted, and the corresponding analog voltage values S ₁₁ , S ₁₂ , S ₁₃ , S ₁₄ are output as control feedback voltages; the first low-high-voltage conversion unit 106 and the second low-high-voltage conversion unit 107 The control feedback voltages S ₁₁ , S ₁₂ , S ₁₃ , and S ₁₄ are amplified, and the low-voltage signals are transformed into high-voltage signals V+ΔV _x , V-ΔV _x , V+ΔV _y , V-ΔV _y .

The first time-division frequency-division multiplexing unit 108 loads the output high-voltage signal of the first low-high voltage conversion unit 106 and the carrier excitation signal V ⁺ to the differential of the rotor of the micro-gyro sensitive unit 100 through RC isolation and frequency division multiplexing. On the capacitors C1-C4, the second time-division frequency-division multiplexing unit 109 loads the output high-voltage signal and the carrier excitation signal V ^of the second low-high voltage conversion unit 107 to the micro-gyroscope sensitive The differential capacitors C5-C8 of the unit 100 jointly control the rotor position of the micro-gyroscope sensing unit 100 at the initial position. The detection circuit is not affected by the demodulation and mixing phenomenon of high-frequency signals, and is suitable for a detection circuit of a high-precision micro-gyroscope.

Claims (3)

1. the rotor type micro gyroscope detection device of time-division frequency division multiplexing, it is characterised in that it includes rotor type micro gyroscope sensitivity list Unit (100), charge voltage converting unit (101), phase demodulation unit (102), AD conversion unit (103), Signal processing unit (104), D/A conversion unit (105), the first low high pressure converting unit (106), the second low high pressure Converting unit (107), the first time-division frequency division multiplexing unit (108) and the second time-division frequency division multiplexing unit (109)；

Carrier wave pumping signal V of the first time-division frequency division multiplexing unit (108)⁺It is loaded onto rotator type with feedback control signal multiplexing First group of multiplexed signals input of microthrust test sensing unit (100)；

Carrier wave pumping signal V of the second time-division frequency division multiplexing unit (109)^-It is loaded onto rotator type with feedback control signal multiplexing Second group of multiplexed signals input of microthrust test sensing unit (100)；

The equivalent gyro signal outfan of rotor type micro gyroscope sensing unit (100) and the input of phase demodulation unit (102) End is connected；

The demodulated signal outfan of phase demodulation unit (102) detects device as the rotor type micro gyroscope of time-division frequency division multiplexing Detection signal output part；

The demodulated signal outfan of phase demodulation unit (102) also with the input end of analog signal of AD conversion unit (103) It is connected；

The digital signal output end of AD conversion unit (103) is connected with the input of signal processing unit (104)；

The outfan of signal processing unit (104) is connected with the digital signal input end of D/A conversion unit (105)；

The analog signal output of D/A conversion unit (105) low pressure with the first low high pressure converting unit (106) simultaneously is believed The low-voltage signal input of number input and the second low high pressure converting unit (107) is connected；

The feedback control signal outfan of the first low high pressure converting unit (106) and the first time-division frequency division multiplexing unit (108) Feedback control signal input be connected；

The feedback control signal outfan of the second low high pressure converting unit (107) and the second time-division frequency division multiplexing unit (109) Feedback control signal input be connected；

Carrier wave pumping signal V⁺With carrier wave pumping signal V^-Phase 180 °.

The rotor type micro gyroscope detection device of time-division frequency division multiplexing the most according to claim 1, it is characterised in that rotator type Microthrust test sensing unit (100) includes four pairs of differential capacitances and a pair pickup electric capacity, and described four pairs of differential capacitances are C1, C5； C2、C6；C3、C7；With C4, C8；The pair of pickup electric capacity is C9, C10；Pickup electric capacity C9 and C10 is in parallel；

The multiplexed signals that differential capacitance C1, C2, C3 and C4 load is carrier wave pumping signal V⁺And feedback control signal；Difference The multiplexed signals dividing electric capacity C5, C6, C7 and C8 to load is carrier wave pumping signal V^-And feedback control signal；

Differential capacitance C1 multiplexing loads carrier wave pumping signal V⁺With feedback control signal V+ △ V_x；

Differential capacitance C2 multiplexing loads carrier wave pumping signal V⁺With feedback control signal V+ △ V_y；

Differential capacitance C3 multiplexing loads carrier wave pumping signal V⁺With feedback control signal V-△ V_x；

Differential capacitance C4 multiplexing loads carrier wave pumping signal V⁺With feedback control signal V-△ V_y；

Differential capacitance C5 multiplexing loads carrier wave pumping signal V^-With feedback control signal V-△ V_x；

Differential capacitance C6 multiplexing loads carrier wave pumping signal V^-With feedback control signal V-△ V_y；

Differential capacitance C7 multiplexing loads carrier wave pumping signal V^-With feedback control signal V+ △ V_x；

Differential capacitance C8 multiplexing loads carrier wave pumping signal V^-With feedback control signal V+ △ V_y；

The input that the outfan of four pairs of differential capacitances picks up electric capacity with in parallel a pair simultaneously is connected, a pair pickup electricity in parallel The outfan held is as the equivalent gyro signal outfan of rotor type micro gyroscope sensing unit (100)；

Wherein: V is carrier wave pumping signal V⁺、V^-Equivalent voltage value, △ V_xFor in X-direction, for making rotor return to The required relative voltage value applied in equilbrium position；△V_yFor in Y direction, for making rotor apply needed for returning to equilbrium position Relative voltage value.

The rotor type micro gyroscope detection device of time-division frequency division multiplexing the most according to claim 1, it is characterised in that phase sensitivity solution Adjust unit (102) by one group of φ₁-φ₄Sequence switch and No. four phase-sensitive demodulators are constituted, and phase demodulation unit (102) is by electric charge The signal that voltage conversion unit (101) exports is demodulated, and exports four road displacement signals.