CN101067555A - Force balancing resonance micro-mechanical gyro - Google Patents

Abstract

The invention relates to an equilibrium type resonance micro mechanical top, which includes static comb tooth driver, mass block, double end tuning fork resonator and static comb tooth strength balancer. When adds the driving voltage to the static comb tooth driver, the mass block does along x axis direction oscillation motion, and circles the z axis in exterior under the rate of angular motion function to produce along y direction coriolis force. The static comb tooth strength balancer used to balance the mass block in y direction Coriolis force and keep the mass block in the equilibrium position of the y direction. The invention structural style enhanced the micro mechanical top sensitivity, the resolution and the dynamic range and realized Coriolis force change, which had the top sensitive angular speed to transform the resonator resonance frequency change, and then through the feedback return route adjustment achieved the new balanced equilibrium type feedback system, and effectively suppressed the non-linear influence.

Description

Force balancing resonance micro-mechanical gyro

Technical field

The invention belongs to the micro mechanical sensor field in the MEMS (micro electro mechanical system) (MEMS), it is widely used in fields such as automotive electronics, Aero-Space, weaponry as little inertia device.

Background technology

Based on the frame-type mechanical rotor gyroscope of the classics of the principle of angular momentum, assemble by hundreds of (about more than 300) parts, complex structure, volume is big, and serviceable life is short, can not satisfy the requirement of technical development and many new application.Thereby developed the solid-state gyro that does not have mechanical rotor in succession, representational have laser gyro, hemispherical reso nance gyroscope and an optical fibre gyro.The performance of preceding two kinds of gyros can reach the inertial navigation level drift accuracies (0.01 °/h); But the price height, volume is bigger, still can not be applicable to the mini inertia measurement unit that developing and the demand of low price business market.And MEMS is in developing period, and its technology and market is prematurity still all, but its wide development prospect that breeds and huge social, economic benefit are that common people know altogether.So, develop micromechanical gyro of new generation (MMG) and be subjected to worldwidely generally paying attention to, and under the promotion of auto industry demand, become the theme of 20th century the mid-80 broad research and development so far.

From test philosophy, silicon micromechanical gyroscope generally adopts the capacitance detecting mode at present.Capacitance detecting has temperature and floats advantages such as little, highly sensitive, reliability number and good stability.But along with constantly dwindling of little inertia device physical dimension, its sensitivity and resolution reduce greatly, have reached the ultimate limit state that detects.The signal to noise ratio (S/N ratio) that detects output signal is very low, and signal deteching circuit and treatment circuit are very complicated, unfavorable miniaturization and integrated.2002, the people such as A.A.Seshia of U.S. Berkeley have proposed a kind of implementation structure of silicon resonance type micromechanical gyro, this structure combines in the past silicon micromechanical gyroscope and micromechanical resonator effectively, thereby avoids the influence of noise in the capacitance detecting effectively.But the vibration dynamic equation of its micromechanical resonator is very complicated, only consider carry-out bit shifting signal under the stable situation be amplitude-modulated signal also be FM signal simultaneously, demodulating process is influenced by non-linear factor.Present micromechanical gyro product hangs down precision in being mostly, seriously restrict its range of application, be applied in the not high commercial kitchen area of accuracy requirement, the performance that improves existing micromechanical gyro is exactly to realize high sensitivity, high resolving power, low noise, low drift and big dynamic range morely.

Summary of the invention

Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, a kind of force balancing resonance micro-mechanical gyro be provided, with solve existing micromechanical gyro sensitivity, resolution is not high enough, and the problem that exists in the capacitance detecting suppresses effect of nonlinear.

Technical solution of the present invention: force balancing resonance micro-mechanical gyro comprises double-ended tuning fork resonator, the static broach driver, four parts of mass and static comb tooth strength balancer, total is a zhou duicheng tuxing, mass mediates, degree of freedom with x and y both direction, suprabasil static broach driver is fixed in two of symmetry placements on its x direction, be symmetrical arranged two on its y direction and be fixed in suprabasil static comb tooth strength balancer and two double-ended tuning fork resonator DETF, mass is driven by the electrostatic force of static broach driver, do vibratory movement along the x direction, if exist along the axial extraneous input angular velocity signal of z, mass will be subjected to the coriolis force effect along the y direction.Static comb tooth strength balancer is used for this coriolis force of balance, make mass on the y direction, be in the equilibrium position, when input angular velocity changes, the coriolis force that cycle changes appears in mass on the y direction, and be delivered on two continuous double-ended tuning fork resonators, and opposite sign but equal magnitude, its natural resonance frequency is changed, but measure the driving voltage of its differential output feedback regulation static comb tooth strength balancer, thereby make mass on the y direction, get back to the equilibrium position, realize the dynamic closed loop of input angular velocity is detected.

Principle of work of the present invention: force balancing resonance micro-mechanical gyro belongs to oscillation gyro (VG), be based on there is the modal coupling effect in excited vibration when Coriolis acceleration is arranged principle and come work, come down to because the existence of section's formula acceleration has caused the NE BY ENERGY TRANSFER between two kinds of mode.Its ultimate principle as shown in Figure 2, wherein mass 3P is connected in the xoy plane of rotating coordinate system, mass P will move along the speed υ of x direction of principal axis with relative rotating coordinate system after being subjected to the electrostatic force driving action of static broach driver, and rotating coordinate system rotates with angular velocity omega around negative z axle.The formula that produces coriolis force because of coriolis effect is F _Cor=-2m _P[ω * υ], promptly mass P is subjected in rotating coordinate system along the coriolis force F of positive y axle _Cor, m wherein _PQuality for plate mass P.As seen coriolis force F _CorDirectly with act on mass P on input angular velocity ω be directly proportional, obtain this coriolis force F _CorInformation also promptly obtain the information of input angular velocity ω.

This coriolis force F _CorCome balance by static comb tooth strength balancer, make mass at coriolis force F _CorBe in the equilibrium position on the direction.The structural drawing of its broach applies driving voltage V (t)=V as shown in Figure 3 on static comb tooth strength balancer _d+ V _iSin ω _pT, the electrostatic force that produces on the x direction of principal axis is: $F_e=\frac{1\&PartialD;\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="A20071010032700081.png,A20071010032700101.png"\; state="\{\{state\}\}">C</figure-callout>}}{2\&PartialD;x}V{\left(t\right)}^2$

$=\frac{1\&PartialD;\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="A20071010032700081.png,A20071010032700101.png"\; state="\{\{state\}\}">C</figure-callout>}}{2\&PartialD;x}({\mathrm{<figure-callout\; id="2"\; label="V\; d"\; filenames="A20071010032700081.png,A20071010032700101.png"\; state="\{\{state\}\}">V</figure-callout>}}_d^{}+\frac{1}{2}{V}_i^2+2V_d{V}_i\sin {\mathrm{\&omega;}}_{p}t-\frac{1}{2}{V}_i^2\mathrm{<figure-callout\; id="2"\; label="cos"\; filenames="A20071010032700081.png,A20071010032700101.png"\; state="\{\{state\}\}">cos</figure-callout>}2{\mathrm{\&omega;}}_{P}t).$ Wherein, $\frac{\&PartialD;C}{\&PartialD;x}=2n{\mathrm{\&epsiv;}}_r{\mathrm{\&epsiv;}}_0\frac{h}{d},$ Promptly Only relevant with the broach gap d with the thickness h of broach, irrelevant with broach width b.At V _iV _dSituation under, the electrostatic force that then is applied on the mass is $F_x=2\frac{\&PartialD;C}{\&PartialD;x}{V}_d{V}_i\sin {\mathrm{\&omega;}}_{p}t.$ By changing driving voltage V (t)=V _d+ V _iSin ω _pThe t size makes electrostatic force F _xBalance coriolis force F _Cor, F is promptly arranged _x=F _Cor

Change moment, coriolis force F at input angular velocity _Cor' ≠ F _x, because the structure of design is a zhou duicheng tuxing, this coriolis force F _Cor' act on the reverse form of constant amplitude on two double-ended tuning fork resonators of two ends symmetry, make its elasticity coefficient k _lBe subjected to modulating the variation of generating period.Its elasticity coefficient k _lBe directly proportional with coriolis force, can be expressed as $k_l=C_{\mathrm{mode}}\frac{F_{\mathrm{cor}}^{\&prime;}}{2L_r},$ C wherein _ModeVibration shape constant for double-ended tuning fork resonator.As shown in Figure 4, double-ended tuning fork resonator becomes coriolis force F axially the time _CorKinetics equation under the ' effect is:

$m_r{\stackrel{\&CenterDot;\&CenterDot;}{x}}_r+b_r{\stackrel{\&CenterDot;}{x}}_r+(k_r+k_l\sin \left({\mathrm{\&omega;}}_{p}t\right))x_r=F_d,$ Wherein, F _dBe the driving force that the driving voltage that is added on the resonator produces, k _rFor resonator be not subjected to coriolis force to make the elasticity coefficient of time spent system, k _lSin (ω _pT) be f for resonator in driving frequency _p=ω _pThe coriolis force F of/2 π _Cor' the down additional elasticity coefficient of modulating action, near zero point, this additive term available linearization is k _lω _pT.The resonance frequency of single double-ended tuning fork resonator is changed to ${\mathrm{\&omega;}}_r=\sqrt{\frac{k_r+k_l{{\mathrm{\&omega;}}_p}^t}{m_r}}\&ap;{\mathrm{\&omega;}}_{r0}+\frac{{\mathrm{\&omega;}}_{r0}}{2}\frac{k_l{\mathrm{\&omega;}}_{p}t}{k_r},$ The differential of resonance frequency variable quantity of two double-ended tuning fork resonators of symmetry is output as $\mathrm{\&Delta;f}=\frac{1}{2\mathrm{\&pi;}}({\mathrm{\&Delta;\&omega;}}_1-{\mathrm{\&Delta;\&omega;}}_2)=\frac{1}{2\mathrm{\&pi;}}2\mathrm{\&Delta;\&omega;}=\frac{{\mathrm{\&omega;}}_{r0}}{2\mathrm{\&pi;}}\frac{k_l{\mathrm{\&omega;}}_{p}t}{k_r}.$ Be control signal, the driving voltage of regulating static comb tooth strength balancer by the dynamic balance control loop makes mass at coriolis force F _Cor' effect is issued to new equilibrium state, thereby realizes the detection to input angular velocity ω.

The present invention's advantage compared with prior art:

(1) double-ended tuning fork resonator of the present invention can realize that the variation of coriolis force that the micromechanical gyro sensitive angular is produced converts the resonator change of resonance frequency to, thereby the driving voltage of feedback regulation static comb tooth strength balancer, effectively avoid the influence of noise in the capacitance detecting, and be easy to digital signal processing.

(2) the coriolis force effect that can balanced microcomputer tool gyro sensitive angular produces of static comb tooth strength balancer of the present invention, make micromechanical gyro be in the static balance state in that this side up, suppressed effect of nonlinear effectively, also solved and used the vibration dynamic equation complexity that exists in the micromechanical resonator testing process separately, only consider stable situation, and the carry-out bit shifting signal be amplitude-modulated signal simultaneously also be the influence of factor such as FM signal.

Description of drawings

Fig. 1 is the schematic diagram of force balancing resonance micro-mechanical gyro of the present invention;

Fig. 2 is a coriolis effect basic principle schematic of the present invention;

Fig. 3 is comb structure figure of the present invention;

Fig. 4 is the structural drawing of double-ended tuning fork resonator of the present invention;

Fig. 5 is embodiment 1 structural drawing of force balancing resonance micro-mechanical gyro of the present invention;

Fig. 6 is embodiment 2 structural drawing of force balancing resonance micro-mechanical gyro.

Embodiment

As shown in Figure 1, the present invention is made up of double-ended tuning fork resonator 1, static broach driver 2, mass 3 and 4 four parts of static comb tooth strength balancer, and total is a zhou duicheng tuxing.Mass 3 mediates, degree of freedom with x and y both direction, suprabasil static broach driver 2 is fixed in two of symmetry placements on its x direction, is symmetrical arranged two on its y direction and is fixed in suprabasil static comb tooth strength balancer 4 and two double-ended tuning fork resonator DETF 1.

As shown in Figure 4, double-ended tuning fork resonator 1 comprises the quiet tooth 6 of driving, measures quiet tooth 7, beam 11 and moving tooth 5, wherein, the tuning fork beam of two symmetries is done simple harmonic oscillation, its outside symmetry places the quiet tooth 6 of driving and the dynamic and static broach of moving tooth 5 formations is right, make double-ended tuning fork resonator 1 be operated in resonant condition by electrostatic force, and realize axial force measurement coming responsive tuning fork beam change of resonance frequency under responsive to axial force by the dynamic and static broach of measuring quiet tooth 7 and moving tooth 5 formations.After adding the drive signal that frequency is double-ended tuning fork resonator 1 resonance frequency on the quiet tooth 6 of driving, mass 3 is done the harmonic moving of y direction, measures quiet tooth 7 export resonance frequency signals.

Static broach driver 2 has identical uniform quiet tooth with static comb tooth strength balancer 4, constitutes dynamic and static broach to structure with the moving tooth that distributes on the mass, produces electrostatic force under driving voltage.The former is used to produce the electrostatic force that mass is done simple harmonic oscillation, and the latter is used for the coriolis force effect that balance gyro sensitive angular produces, and makes gyro be in the equilibrium position on the coriolis force direction.

The schematic diagram of force balancing resonance micro-mechanical gyro shown in Figure 1 can have multiple structural drawing to realize, illustrates, and the implementation structure of force balancing resonance micro-mechanical gyro as shown in Figure 5 and Figure 6 can be arranged.As shown in Figure 5, structure is a zhou duicheng tuxing, and mass 3 comprises inner moving tooth framework and external frame, fixes with substrate by four brace summers 9 and anchor point 8.Place four and be fixed in suprabasil static broach driver 2 on the inner x direction of the moving tooth framework in inside, externally symmetry is placed two and is fixed in suprabasil static comb tooth strength balancer 4 and two double-ended tuning fork resonators 1 on the outside y direction of framework.As shown in Figure 6, structure is a zhou duicheng tuxing, and mass 3 is a tabular, mediates, and fixes with substrate by four brace summers 9 and anchor point 8.Suprabasil static broach driver 2 is fixed in two of symmetry placements on its x direction, symmetry is placed two and is fixed in suprabasil static comb tooth strength balancer 4 on its y direction, and is fixed in two double-ended tuning fork resonators 1 of the suprabasil lever enlarger 10 and the outside by two and links to each other.Wherein, lever enlarger 10 utilizes typical lever principle, utilizes anchor electricity 8 to be fulcrum, reaches the effect of amplifying coriolis force by reducing the arm of force.

In the structure of the present invention, substrate material is a glass, and the sensitive structure material is a monocrystalline silicon, adopts the bulk silicon technological of standard to make, and polysilicon micromechanical gyro more in the past has favorable mechanical characteristic more.

Claims (3)

1, force balancing resonance micro-mechanical gyro, it is characterized in that: comprise double-ended tuning fork resonator (1), static broach driver (2), mass (3), and static comb tooth strength balancer (4), structure is a zhou duicheng tuxing, the centre is mass (3), degree of freedom with x and y both direction, place two on its x direction and be fixed in suprabasil static broach driver (2), be provided with two on its y direction and be fixed in suprabasil static comb tooth strength balancer (4) and two double-ended tuning fork resonators (1), mass (3) is driven by the electrostatic force of static broach driver (2), do vibratory movement along the x direction, if exist along the axial extraneous input angular velocity signal of z, mass will be subjected to the coriolis force effect along the y direction, static comb tooth strength balancer (4) is used for this coriolis force of balance, make mass on the y direction, be in the equilibrium position, when input angular velocity changes, the coriolis force that cycle changes appears in mass (3) on the y direction, and be delivered on continuous two double-ended tuning fork resonators (1), and opposite sign but equal magnitude, its natural resonance frequency is changed, but measure the driving voltage of its differential output feedback regulation static comb tooth strength balancer (4), thereby make mass (3) on the y direction, get back to the equilibrium position, realize the dynamic closed loop of input angular velocity is detected.

2, force balancing resonance micro-mechanical gyro according to claim 1, it is characterized in that: described double-ended tuning fork resonator (1) can be realized the resonant mode detection mode, it adopts the tuning fork beam of two symmetries that are operated in the simple harmonic oscillation state, realize to axial force measurement that by responsive tuning fork beam change of resonance frequency under responsive to axial force symmetry placement driving and pick-up device make it be operated in resonant condition outside two tuning fork beams.

3, force balancing resonance micro-mechanical gyro according to claim 1, it is characterized in that described static comb tooth strength balancer (4) has identical uniform quiet tooth with static broach driver (2), go up the moving tooth that distributes with mass (3) and constitute dynamic and static broach structure, under driving voltage, produce electrostatic force, be used for the coriolis force effect that balance gyro sensitive angular produces, make gyro be in the equilibrium position in that this side up, suppressed effect of nonlinear effectively.

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