CN103115618B - Isolation test method for orthoronal errors and parasitic coriolis force based on vibrating type micromechanical gyroscope - Google Patents

Abstract

The invention discloses an isolation test method for orthoronal errors and parasitic coriolis force vibrating type micromechanical gyroscope-based. The method comprises the following steps of: inputting a large angular velocity signal rotating around a sensitive shaft into a vibrating type micromechanical gyroscope, and measuring the amplitude of an alternating current signal of an output end of a detection direction processing circuit and the phase difference between the alternating current single and a drive signal of the vibrating type micromechanical gyroscope; resetting the input angular velocity signal to be zero, and measuring the amplitude of the alternating current signal of the output end of the detection direction processing circuit and the phase difference between the alternating current single and the drive signal; and successfully isolating the orthoronal errors from the parasitic coriolis force according to a measurement result; adjusting the phase of a single of an output end of a feedback direction processing circuit by a phase shifter in the feedback direction processing circuit, so that the phase of the signal of the output end of the feedback direction processing circuit is accordant with the phase of a signal, caused by a coriolis acceleration signal, of the output end of the detection direction processing circuit; and therefore, the maximum sensitivity of a gyroscope system can be realized through the coherent demodulation and the lowpass filtering of a rear-stage circuit.

Description

A kind of discrete testing method of quadrature error based on vibrating micromechanical gyro and parasitic coriolis force

Technical field

The present invention relates to micromechanical gyro sensor field, particularly relate to the discrete testing to vibrating micromechanical gyro inner orthogonal error and these two kinds of coupled signals of parasitic coriolis force.

Background technology

The principle of work of vibrating micromechanical gyro is all that its kinetic model as shown in Figure 1 based on Coriolis (Coriolis) effect.When movable mass does simple harmonic oscillation in X direction, if now rich Z axis has an angular velocity of rotation input, so movable mass will be subject to the effect of Coriolis acceleration in the Y direction.Wherein, the size of Coriolis acceleration is directly proportional to the movement velocity v of input angular velocity Ω and mass, and the direction of its direction and angular velocity and movement velocity is perpendicular, shown in (1).Therefore the movement velocity by detecting Coriolis acceleration and mass can obtain the size of input angular velocity.

${\stackrel{\→}{a}}_C=2\stackrel{\→}{\mathrm{\Ω}}\×\stackrel{\→}{v}---\left(1\right)$

Vibrating micromechanical gyro sensor driving direction and detection side to the equation of motion can represent respectively as shown in (2) and (3).

$M_x\stackrel{\·\·}{x\left(t\right)}+c_x\stackrel{\·}{x\left(t\right)}+k_{x}x\left(t\right)=F_{\mathrm{drive}}---\left(2\right)$

$M_y\stackrel{\·\·}{y\left(t\right)}+c_y\stackrel{\·}{y\left(t\right)}+k_{y}y\left(t\right)=2M_y\mathrm{\Ω}\stackrel{\·}{x\left(t\right)}---\left(3\right)$

In formula (2) and formula (3), M _xand M _yrespectively represent drive and detection side to mass quality; c _xand c _yrespectively represent drive and detection side to ratio of damping; k _xand k _yrespectively represent drive and detection side to elasticity coefficient; X (t), represent driving direction displacement, speed, acceleration respectively; Y (t), represent that detection side is to displacement, speed, acceleration respectively; Ω represents input angular velocity; represent Coriolis power; F _driverepresenting makes gyro in the additional driving force of driving direction resonance, F _drive=F ₀sin (ω _dt), F ₀for the amplitude of driving force, ω _dfor the angular frequency of driving force.

Vibrating micromechanical gyro detection side to displacement expression formula such as formula shown in (4).

y(t)＝B _ysin(ω _dt-φ _y) (4)

In formula (4), B _yfor detection side is to the amplitude of vibration displacement, φ _yfor detection side is to the phase place of vibration displacement.

In the manufacturing process of vibrating micromechanical gyro sensor, the additional driving force direction caused due to fabrication error not overlaps completely with driving shaft, but departs from certain angle θ ₁, as shown in Figure 2.Angle θ ₁existence make driving force upwards there is certain component detection side.Now detection side to kinetics equation such as formula shown in (5).Here it is so-called parasitic coriolis force.Because the phase place of parasitic coriolis force is consistent with the phase place of Coriolis power, therefore the method by phase demodulation on circuit cannot be eliminated, thus introduced direct current biasing at the output terminal of gyrosystem.

$M_y\stackrel{\·\·}{y\left(t\right)}+c_y\stackrel{\·}{y\left(t\right)}+k_{y}y\left(t\right)=2M_y\mathrm{\Ω}\stackrel{\·}{\stackrel{\·}{x\left(t\right)}+F_{\mathrm{drive}}\sin {\mathrm{\θ}}_1}---\left(5\right)$

In the manufacturing process of vibrating micromechanical gyro sensor, because the reason such as craft precision and material stress causes driving shaft and detection axis and non-fully is orthogonal, but depart from must angle θ ₂, as shown in Figure 3.Angle θ ₂existence make mass upwards have an oscillating component in the vibration of driving direction detection side, detection side to displacement expression formula as shown in (6).Due to the vibration phase difference 90 degree that this oscillating component and Coriolis power cause, therefore this coupling effect is called as quadrature error.The method of phase demodulation can be adopted in late-class circuit to eliminate the impact of this error on sensor output signal.

y(t)＝B _ysin(ω _dt-φ _y)+x(t)sinθ ₂(6)

The block diagram of existing vibrating micromechanical gyro system as shown in Figure 4.Gyrosystem is made up of vibrating micromechanical gyro sensor and peripheral processes circuit two parts.Treatment circuit comprises drive signal generation circuit, feedback direction treatment circuit, detection side to treatment circuit, coherent demodulator and low-pass filter.The output terminal of drive signal generation circuit is connected with the drive end of vibrating micromechanical gyro sensor, the detection signal output terminal of vibrating micromechanical gyro sensor is connected to the input end for the treatment of circuit with detection side, the feedback signal output of vibrating micromechanical gyro sensor is connected with the input end of feedback direction treatment circuit, detection side is connected with two signal input parts of coherent demodulator to the output terminal for the treatment of circuit respectively with the output terminal of feedback direction treatment circuit, the output terminal of coherent demodulator is connected with the input end of low-pass filter, low-pass filter exports d. c. voltage signal, this signal is directly proportional to input angular velocity signal.Described detection side to treatment circuit by vibrating micromechanical gyro detection side to displacement signal be converted to voltage signal, the displacement signal that vibrating micromechanical gyro is fed back direction by described feedback direction treatment circuit is converted to voltage signal.The expression formula of the output signal of feedback direction treatment circuit is such as formula shown in (7).

V _feedback＝V _fsin(ω _dt-φ _x+φ _f) (7)

${\mathrm{\φ}}_x={\mathrm{tg}}^{-1}\frac{2{\mathrm{\ζ}}_x{\mathrm{\ω}}_x{\mathrm{\ω}}_d}{{{\mathrm{\ω}}_x}^2-{\mathrm{\ω}}_d^2}---\left(8\right)$

In formula (7) and (8), ω _xfor the natural angular frequency of driven-mode, ζ _x=c _x/ 2M _xω _xfor the damping ratio of driven-mode, φ _ffor feedback direction treatment circuit is to the phase shift of feedback signal.

Detection side to the expression formula of the output signal for the treatment of circuit such as formula shown in (9).

V _sense＝V _Coriolissin(ω _dt-φ _y+φ _s)+Asin(ω _dt+φ _s)+Bsin(ω _dt-φ _x+φ _s) (9)

${\mathrm{\φ}}_y={\mathrm{tg}}^{-1}\frac{2{\mathrm{\ζ}}_y{\mathrm{\ω}}_y{\mathrm{\ω}}_d}{{{\mathrm{\ω}}_y}^2-{\mathrm{\ω}}_d^2}+{\mathrm{\φ}}_x---\left(10\right)$

In formula (9) and (10), ω _yfor the natural angular frequency of sensed-mode, ζ _y=c _y/ 2M _yω _yfor the damping ratio of sensed-mode, φ _sfor detection side is to the phase shift for the treatment of circuit to detection signal, V _coriolisfor the voltage signal caused by Coriolis acceleration, the amplitude of the coupled voltages signal of A caused by parasitic coriolis force, the amplitude of the coupled voltages signal of B caused by quadrature error.

Work as ω _d=ω _x=ω _ytime, φ _x=90 °, φ _v=180 °.Therefore formula (7) and formula (9) can be reduced to:

V _feedback＝V _fcos(ω _dt+φ _f) (11)

V _sense＝-V _Coriolissin(ω _dt+φ _s)+Asin(ω _dt+φ _s)+Bcos(ω _dt+φ _s) (12)

When input angular velocity signal is zero, V _coriolis=0, therefore detection side only comprises the coupled signal caused by parasitic coriolis force and quadrature error in the signal for the treatment of circuit output terminal, and its expression formula is:

V _sense＝Asin(ω _dt+φ _s)+Bcos(ω _dt+φ _s) (13)

The phase shifter of feedback treatment circuit inside, direction is utilized to regulate feedback direction treatment circuit output end signal V _feedbackphase place, make it consistent with the phase place of the voltage signal caused by Coriolis acceleration, namely consistent with the phase place of the coupled signal caused by parasitic coriolis force.Now, the sensitivity of gyrosystem is maximum.But due to V _sensein comprise two kinds of coupled signals caused by parasitic coriolis force and quadrature error, and there is the phase differential of 90 degree between the two, therefore V _sensephase place namely not consistent with the phase place of the coupled signal caused by parasitic coriolis force, also not consistent with the phase place of the coupled signal caused by quadrature error, signal schematic representation is as shown in Figure 5.So just cannot determine the phase shift size of the phase shifter feeding back treatment circuit inside, direction.If can not accurate adjustment phase place, the sensitivity of maximum gyrosystem just can not be obtained.

Therefore, need to take someway by V _sensemiddle comprised parasitic coriolis force and two kinds of coupled signals caused by quadrature error are separated, thus can the phase place of accurate adjustment feedback direction treatment circuit output signal, realize the maximization of gyrosystem sensitivity.

Summary of the invention

The object of this invention is to provide a kind of method two kinds of coupled signals caused by the quadrature error of vibrating micromechanical gyro sensor internal and parasitic coriolis force can separated.

The technical solution used in the present invention is: in vibrating micromechanical gyro system, inputs a large angular velocity signal rotated around Z axis to system.Measure the amplitude of detection side to treatment circuit output terminal AC signal.Measure detection side to the phase differential between treatment circuit output terminal AC signal and the drive singal of vibrating micromechanical gyro sensor.Make the input angular velocity of vibrating micromechanical gyro system be zero, measure the amplitude of detection side to treatment circuit output terminal AC signal.Measure detection side to the phase differential between treatment circuit output terminal AC signal and the drive singal of vibrating micromechanical gyro sensor.The result utilizing above-mentioned measurement to obtain can calculate parasitic coriolis force and quadrature error respectively the detection side of vibrating micromechanical gyro system to the size of the coupled voltages signal caused by treatment circuit output terminal, successfully achieve and two coupled signals be separated.Utilize the phase shifter of feedback treatment circuit inside, direction to regulate the phase place of feedback direction treatment circuit output end signal, make it consistent to the phase place of the signal for the treatment of circuit output terminal with the detection side caused by Coriolis acceleration signal.Now feed back after the signal of direction treatment circuit output terminal and detection side carry out coherent demodulation and low-pass filtering to the signal for the treatment of circuit output terminal, the sensitivity of gyrosystem is maximum.

The beneficial effect that the present invention has is:

1) the invention provides a kind of method two kinds of coupled signals caused by the quadrature error of vibrating micromechanical gyro sensor internal and parasitic coriolis force can separated.The implementing of the method helps the size analyzing the parasitic coriolis force of vibrating micromechanical gyro sensor internal and quadrature error, for the technological process optimizing sensor processing provides guidance.

2) the present invention accurately can be separated quadrature error and two kinds of coupled signals caused by parasitic coriolis force, therefore, it is possible to feed back the phase place of direction treatment circuit output signal in accurate adjustment vibrating micromechanical gyro system, the sensitivity of gyrosystem is made to reach maximum.

Accompanying drawing explanation

Fig. 1 is the kinetic model of vibrating micromechanical gyro.

Fig. 2 is the schematic diagram of vibrating micromechanical gyro endophyte coriolis force.

Fig. 3 is the schematic diagram of vibrating micromechanical gyro inner orthogonal error.

Fig. 4 is the schematic diagram of vibrating micromechanical gyro system architecture diagram.

Fig. 5 be the coupled signal caused by parasitic coriolis force in vibrating micromechanical gyro system, the coupled signal caused by quadrature error and two coupled signals with the waveform schematic diagram of signal.

Embodiment

Visible according to formula (12), the phase place of the Coriolis signal caused by input angular velocity is identical with the phase place of the coupled signal caused by parasitic coriolis force, and both sums can be expressed as:

-V _Coriolissin(ω _dt+φ _s)+Asin(ω _dt+φ _s)＝Csin(ω _dt+φ _s) (14)

Now, detection side to the expression formula of the output signal for the treatment of circuit such as formula shown in (15).

When turning rate input signal is very large, i.e. C > > B, therefore namely namely detection side to the signal for the treatment of circuit output terminal is:

$V_{\mathrm{sense}}=C\sin ({\mathrm{\ω}}_{d}t+{\mathrm{\φ}}_s)+B\cos ({\mathrm{\ω}}_{d}t+{\mathrm{\φ}}_s)=\sqrt{C^2+B^2}\sin ({\mathrm{\ω}}_{d}t+{\mathrm{\φ}}_s)---\left(17\right)$

By the phase differential between the drive singal of determining this signal and vibrating micromechanical gyro sensor, can obtain detection side to treatment circuit is ω to frequency _dthe phase shift φ of signal _s.

When input angular velocity signal is zero, V _coriolis=0, therefore detection side only comprises the coupled signal caused by parasitic coriolis force and quadrature error in the signal for the treatment of circuit output terminal, and its expression formula is:

Therefore, can be obtained to the amplitude for the treatment of circuit output end signal by measurement detection side size V _x, can obtain to the phase differential between treatment circuit output end signal and the drive singal of vibrating micromechanical gyro sensor by measuring detection side size, the phase shift φ recorded before utilization _s, can obtain size.Obtain following relevant with A and B system of equations.

Solving equations (20) can obtain the size of A and B, thus by V _sensemiddle the comprised coupled signal caused by parasitic coriolis force and the coupled signal caused by quadrature error are separated.

Implementation step is as follows:

1) in vibrating micromechanical gyro system, an angular velocity signal rotated around Z axis is inputted to system,

Size can be 300 degree/second.

2) measure detection side to the amplitude for the treatment of circuit output terminal AC signal, can obtain size.

3) measure detection side to the phase differential between treatment circuit output terminal AC signal and the drive singal of vibrating micromechanical gyro sensor, can φ be obtained _ssize.

4) make the input angular velocity of vibrating micromechanical gyro system be zero, measure detection side to the amplitude for the treatment of circuit output terminal AC signal, can obtain size V _x.

5) measure detection side to the phase differential between treatment circuit output terminal AC signal and the drive singal of vibrating micromechanical gyro sensor, can obtain size.

6) utilize and φ _ssize can obtain size.

7) V is utilized _xwith size, the value of A and B can be calculated.Therefore known parasitic coriolis force and quadrature error respectively the detection side of vibrating micromechanical gyro system to the size of the coupled voltages signal caused by treatment circuit output terminal, successfully achieve and two coupled signals be separated.

8) according to φ _ssize, utilize feedback treatment circuit inside, direction phase shifter regulate feedback direction treatment circuit output end signal V _feedbackphase place, make it consistent to the phase place of the signal for the treatment of circuit output terminal with the detection side caused by Coriolis acceleration signal, i.e. φ _f=90 ° of+φ _s.Now feed back after the signal of direction treatment circuit output terminal and detection side carry out coherent demodulation and low-pass filtering to the signal for the treatment of circuit output terminal, the sensitivity of gyrosystem is maximum.

Claims (2)

1. the discrete testing method of the quadrature error based on vibrating micromechanical gyro and parasitic coriolis force, it is characterized in that: input a large angular velocity signal rotated around sensitive axes to vibrating micromechanical gyro, the detection side that the detection side that Coriolis force and parasitic coriolis force are caused jointly causes to the amplitude of output signal much larger than quadrature error is to the amplitude of output signal, measure detection side to the amplitude for the treatment of circuit output terminal AC signal and detection side to the phase differential between treatment circuit output terminal AC signal and the drive singal of vibrating micromechanical gyro sensor, the input angular velocity of vibrating micromechanical gyro is made to be zero again, measure amplitude from detection side to treatment circuit output terminal AC signal and measure detection side to the phase differential between treatment circuit output terminal AC signal and the drive singal of vibrating micromechanical gyro sensor, above-mentioned measurement result is utilized to obtain quadrature error and parasitic coriolis force respectively in the size of detection side to the coupled voltages signal caused by treatment circuit output terminal, success realizes two coupled signals to be separated.

2. one kind realizes the maximized method of vibrating micromechanical gyro system sensitivity, it is characterized in that: the quadrature error of vibrating micromechanical gyro obtained according to claim 1 and the discrete testing result of parasitic coriolis force, the phase shifter of feedback treatment circuit inside, direction is utilized to regulate the phase place of feedback direction treatment circuit output end signal, make it consistent to the phase place of the signal for the treatment of circuit output terminal with the detection side caused by Coriolis acceleration signal, the maximization of the sensitivity of vibrating micromechanical gyro system can be realized.