阅读说明：本技术 一种硅微环形谐振陀螺的刚性主轴定位与激光平衡匹配算法 (Rigid spindle positioning and laser balance matching algorithm of silicon micro-ring resonator gyroscope ) 是由 白泽森 崔健 杨振川 赵前程 于 2019-08-30 设计创作，主要内容包括：本发明提供一种用于硅微环形谐振陀螺的刚性主轴的定位与激光平衡匹配算法,包括正交耦合调零、模态频率匹配,刚性主轴定位、激光平衡匹配,四个步骤。加工不完美的环形陀螺存在一个刚度较大的刚性主轴,可以利用电学方法,求解得到刚性主轴的位置,并在谐振环的内侧的相应位置通过激光修调的方法去除小质量块,改变陀螺驱动轴和检测轴刚度失配的情况。这个算法可以从根本上消除硅微环形陀螺加工后的不对称和不完美,平衡匹配后的环形谐振陀螺的正交耦合误差将被彻底抑制,陀螺将工作在驱动模态和检测模态频率相等的匹配状态,可以实现的高精度、高稳定性的角速度检测。(The invention provides a positioning and laser balance matching algorithm for a rigid spindle of a silicon micro-ring resonator gyroscope, which comprises four steps of orthogonal coupling zero setting, modal frequency matching, rigid spindle positioning and laser balance matching. The imperfect annular gyroscope is processed to form a rigid main shaft with higher rigidity, the position of the rigid main shaft can be obtained by solving through an electrical method, the small mass block is removed at the corresponding position of the inner side of the resonant ring through a laser trimming method, and the condition of rigidity mismatch of a gyroscope driving shaft and a detection shaft is changed. The algorithm can fundamentally eliminate the asymmetry and imperfection of the processed silicon micro-ring gyroscope, the orthogonal coupling error of the ring resonator gyroscope after balanced matching can be thoroughly inhibited, the gyroscope can work in a matching state with equal frequency of a driving mode and a detection mode, and the high-precision and high-stability angular velocity detection can be realized.)

1. A positioning and laser balance matching algorithm for a rigid spindle of a silicon micro-ring resonator gyroscope is characterized in that: the algorithm comprises four steps of quadrature coupling zero setting, modal frequency matching, rigid spindle positioning and laser balance matching. The rigid principal axis refers to a resonance direction of a mode with a higher resonance frequency in two working modes of the ring gyroscope.

2. The algorithm of claim 1 for matching the alignment of rigid principal axes of silicon micro-ring resonator gyroscopes to laser balance, wherein: the first step of the algorithm is orthogonal coupling zero setting, and the annular gyroscope is driven in a driving mode closed loop mode by two driving electrodes of the annular gyroscope. The drive mode closed-loop drive means that after the annular gyroscope is forced to vibrate, vibration displacement is picked up by the two drive detection electrodes, and a phase-locked loop of the drive mode is completed according to the phase difference between a vibration displacement signal and a drive signal. And after the drive mode is closed, reading signals of the two sensitive detection electrodes, adjusting the voltages of the eight orthogonal zero setting electrodes simultaneously, and recording the orthogonal coupling zero setting voltage when the signals of the two sensitive detection electrodes reach the minimum, so that the orthogonal coupling zero setting is completed.

3. The algorithm of claim 1 for matching the alignment of rigid principal axes of silicon micro-ring resonator gyroscopes to laser balance, wherein: and the modal frequency matching in the second step of the algorithm is realized, the modal closed loop is driven on the basis of the quadrature coupling zero setting in the last step, signals of two sensitive detection electrodes are read, the voltages of four frequency matching electrodes are simultaneously adjusted, when the signals of the two sensitive detection electrodes reach the maximum, the frequency matching voltage at the moment is recorded, and the modal frequency matching is completed.

4. The algorithm of claim 1 for matching the alignment of rigid principal axes of silicon micro-ring resonator gyroscopes to laser balance, wherein: and the third step of the algorithm is rigid spindle positioning, and the position of the rigid spindle of the annular gyroscope is calculated by using the voltage recorded when the orthogonal coupling zero setting is finished and the voltage recorded when the frequency matching is finished.

5. The algorithm for matching the alignment of the rigid principal axis of the silicon micro-ring resonator gyroscope and the laser balance as set forth in claim 1, wherein: and the fourth step of the algorithm is laser balance matching, and a laser is used for removing the small mass block on the inner side of the resonant ring so that the annular gyroscope reaches a state of complete matching of two modes. And the position for removing the small mass block is at the inner side of the corresponding resonance ring in the rigid main shaft direction of the resonance ring. The two modes are completely balanced and matched, the annular gyroscope works under the condition of driving a closed loop, all orthogonal coupling zero adjusting electrodes and the frequency matching electrodes are grounded in a direct current flow mode, stepping laser trimming is started simultaneously, when signals of the two sensitive detection electrodes reach the minimum, trimming is stopped, laser balance matching is completed, and the silicon micro-annular gyroscope reaches the intrinsic mode matching state on the mechanical structure.

The technical field is as follows:

the invention relates to a rigid spindle positioning and laser balancing algorithm for a silicon micro-ring gyroscope, wherein the silicon micro-ring gyroscope works in a mode matching state, namely the driving mode frequency and the detection mode frequency of the gyroscope are equal, however, due to the non-ideal characteristics of processing materials and processing technology, the frequencies of the two modes are often not equal, and at the moment, the mode frequency of the gyroscope can be changed by a method of removing a small mass block by laser after the rigid spindle of the gyroscope is found, so that the balance matching is realized.

Background art:

compared with the traditional gyroscope, the silicon micromechanical gyroscope is manufactured on a silicon chip in batches by a microelectronic process and then packaged at a wafer level, the silicon micromechanical gyroscope has the advantages of low cost, small volume, low power consumption and the like, and the silicon micromechanical gyroscope has the advantages of strong environmental interference resistance, high reliability and the like. In the consumer-grade field, such as smart phones, smart watches/bracelets, silicon micro-gyroscopes have become standard accessories; in the industrial field, in the aspects of mechanical arm positioning, automobile rolling detection and the like, the silicon micro gyroscope plays an irreplaceable role; in some more demanding scenes, such as various stable platforms and remote guidance devices, the silicon micromechanical gyroscope also has excellent performance. The principle of silicon micromechanical gyros is to use a frequency-stable, non-stop vibrating mechanical structure (commonly called a harmonic oscillator) to induce coriolis forces. The ring-shaped resonance gyroscope taking the resonance ring as the harmonic oscillator has the natural advantages of high mechanical sensitivity, stable temperature characteristic, insensitivity to impact vibration and the like by benefiting from the mechanical characteristics of a rotational symmetric structure and uniform mass distribution of the ring-shaped resonance gyroscope, and is regarded as an important development technical direction of the silicon micromechanical gyroscope in the future.

The silicon micro-ring resonator gyroscope needs to work under the condition of mode matching, namely the driving mode frequency is equal to or approximately equal to the detection mode frequency, which is an important precondition for excellent performance of the silicon micro-ring resonator gyroscope. However, any imperfections in the process and the asymmetry of the processed material in the mechanical representation can cause the processed gyroscope to have a non-negligible inter-modal frequency difference. The monocrystalline silicon is etched by laser, redundant and asymmetrical small mass blocks are removed, and the technical path for solving the problems is provided. At the university of California at Berkeley's university, a published paper "Location-dependent frequency tuning of resonant micro mechanical resonators via laser trimming" was proposed to modify the frequency of the resonator, and later at the JPL laboratory in the United states, the defense science and technology university in China, the laser was used to perform quadrature coupling suppression on the clover-leaf gyroscope and the butterfly gyroscope. In the text, aiming at the problem of mismatching and unbalance of the annular gyroscope, the method for solving the mismatching and unbalance of the annular gyroscope is to find a rigid main shaft of a gyroscope working mode by using an electrical method, namely a resonance direction corresponding to one of a driving mode and a detection mode with higher frequency, remove a small mass block of a resonance ring in the direction of the rigid main shaft by using laser, and adjust the rigidity of the rigid main shaft until the frequencies of the two modes are equal to realize balanced matching. The invention has the significance of providing a rigid spindle positioning and laser balance matching algorithm for the silicon micro-ring gyroscope, which can fundamentally eliminate the orthogonal coupling of the ring gyroscope and complete the mode matching, thereby providing a guarantee of a mechanical layer for the high-sensitivity angular velocity detection.

The invention content is as follows:

the invention aims to provide a positioning and laser balance matching algorithm for a rigid main shaft of a silicon micro-ring resonator gyroscope, which is used for fundamentally eliminating asymmetry and imperfection of the processed silicon micro-ring gyroscope, the orthogonal coupling of the balanced and matched ring resonator gyroscope is thoroughly inhibited, and the gyroscope can work in a state of equal frequency of a driving mode and a detection mode, so that the gyroscope can be detected with high precision and high stability.

In order to achieve the purpose, the invention adopts the following technical scheme:

a positioning and laser balance matching algorithm for a rigid spindle of a silicon micro-ring resonator gyroscope is characterized in that: the method comprises four steps of orthogonal coupling zero setting, modal frequency matching, rigid spindle positioning and laser balance matching.

The rigid principal axis refers to a resonance direction of a mode with a higher resonance frequency in two working modes of the ring gyroscope.

And in the first step, orthogonal coupling zero setting is carried out, and the annular gyroscope is driven in a driving mode closed loop mode by two driving electrodes of the annular gyroscope. The drive mode closed-loop drive means that after the annular gyroscope is forced to vibrate, vibration displacement is picked up by the two drive detection electrodes, and a phase-locked loop of the drive mode is completed according to the phase difference between a vibration displacement signal and a drive signal. After driving the modal closed loop, reading signals of the two sensitive detection electrodes, adjusting the voltages of the eight orthogonal zero setting electrodes simultaneously, when the signals of the two sensitive detection electrodes reach the minimum, considering that the orthogonal coupling has been set to zero, and recording the orthogonal zero setting voltage at the moment.

And the second step of modal frequency matching is to read signals of two sensitive detection electrodes after completing driving modal closed loop on the basis of the last step of orthogonal coupling zero setting, adjust the voltages of four frequency matching electrodes simultaneously with the signals, consider that the modal frequency matching is realized when the signals of the two sensitive detection electrodes reach the maximum, and record the frequency matching voltage at the moment.

And in the third step, the rigid spindle is positioned, and the position of the rigid spindle of the annular gyroscope is calculated by utilizing the orthogonal zero setting voltage and the frequency matching voltage.

And laser balance matching is carried out in the fourth step, and a high-power laser is used for removing a small mass block on the inner side of the resonant ring so that the annular gyroscope reaches a state of complete matching of two modes. The position of the removed small mass is arranged on the inner side of the resonance ring corresponding to the rigid main shaft of the resonance ring, generally speaking, in order to ensure the linearity of laser trimming, the width of the removed mass is not more than 1/10 of the width of the resonance ring, the length of the removed mass is not more than 1/20 of the circumference of the resonance ring, and the thickness of the removed mass is equal to the thickness of the resonance ring of the gyroscope. The two completely-matched modes are marked in such a way that when the annular gyroscope works under the condition of driving a closed loop, all the orthogonal coupling zero adjusting electrodes and the frequency matching electrodes are grounded, stepping laser trimming is started, and when the signals of the two sensitive detection electrodes reach the minimum, the silicon micro-annular gyroscope is considered to reach the intrinsic mode matching state of the mechanical angle at the moment.

Due to the adoption of the technical scheme, the invention has the following advantages: 1. the whole process is based on program setting, the balance matching 2 of the silicon micro gyroscope and the balance matching method based on laser trimming can be completed automatically, orthogonal coupling is restrained from the angle of a mechanical structure, mode matching is completed, circuit design and controller design are simplified, and high-precision and high-stability angular velocity detection is easier to complete.

Drawings

FIG. 1 is a schematic diagram of rigid principal axis of a silicon micro-ring resonator gyroscope

FIG. 2 electrode configuration for solving rigid spindle position of silicon micro-ring resonator gyroscope

FIG. 3 is a block diagram of rigid spindle positioning and laser balancing algorithm for silicon micro-ring resonator gyroscope

FIG. 4 rigid principal axis positioning and laser balancing example of silicon micro-ring resonator gyroscope

Detailed Description

The technical solutions of the present invention are described in detail below with reference to the accompanying drawings and the detailed description, but the scope of the present invention is not limited to the embodiments.

As shown in fig. 1 to 3, a system for balancing static electricity when a silicon micro-ring resonator gyroscope is started is characterized in that: a positioning and laser balance matching algorithm for a rigid spindle of a silicon micro-ring resonator gyroscope is characterized in that: the method comprises four steps of orthogonal coupling zero setting, modal frequency matching, rigid spindle positioning and laser balance matching.

The rigid main shaft, as shown in FIG. 1, is ω of two working modes of the ring gyroscope 102_dAnd ω_sOmega of higher frequency_dThe resonant frequency of the drive mode is at an angle θ to the horizontal.

The first step of quadrature coupling zeroing is to drive the ring gyroscope at two driving electrodes 201 and 205 of the ring gyroscope, as shown in fig. 2, where the driving voltage is an ac signal 2V_dThe ring gyro is forced to vibrate, and the vibration displacement is picked up by two drive detection electrodes 209 and 213 to be 2V_dsAccording to the vibration displacement signal V_dsThe phase of (b) completes the phase-locked loop of the drive mode, i.e. the drive mode closed loop. After the drive mode is closed loop, the signals 2V of the two sensitive detection electrodes 211 and 215 are read_ssSimultaneously adjusting the voltages V of the eight orthogonal zero setting electrodes 202, 206, 210, 214_tcAnd 204, 208, 212, 206 voltage-V_tcWhen the signals of the two sensitive detection electrodes 211 and 215 are 2V_ssWhen it reaches the minimumWe consider the quadrature coupling to have been zeroed and record the quadrature zeroing voltage V at that time_tc。

The second step of modal frequency matching means that, on the basis of the previous step of orthogonal coupling zero setting, after the driving modal closed loop is completed, the signals 2V of the two sensitive detection electrodes 211 and 215 are read_ssSimultaneously adjusting the voltages V of the four frequency matching electrodes 201, 205_tfAnd 203, 207 of voltage-V_tfWhen the signals of the two sensitive detection electrodes 211 and 215 are 2V_ssWhen the maximum is reached, we consider that the modal frequency matching is realized, and record the frequency matching voltage V at the moment_tf。

The third step of rigid spindle positioning is to calculate the position of the rigid spindle of the annular gyroscope by using orthogonal zero setting voltage and frequency matching voltage, and the calculation process of the embodiment is as follows:

the potentials of the 16 electrodes in fig. 2 are:

V₁＝V₅＝V_tf

V₃＝V₇＝-V_tf

V₂＝V₆＝V₁₀＝V₁₄＝V_tc

V₄＝V₈＝V₁₂＝V₁₆＝-V_tc

V₉＝V₁₁＝V₁₃＝V₁₅＝GND

let the capacitor gap be d₀The capacitance of the electrode is C₀I is the number of each electrode, 2 alpha is the radian of the electrode,for the position of the electrode, the horizontal left direction is specified to be the zero axis direction, the anticlockwise direction is specified to be positive, and then the influence of the voltage of the single electrode on the rigidity matrix of the ring-shaped gyroscope is as follows:

to simplify the calculation, we remember:

C＝2α＝(A+B)/2

bringing into position each electrode, the contribution of each electrode to the stiffness of the toroidal gyro can be obtained:

if the rigid main axis position of the annular gyroscope is recorded as θ, the intrinsic stiffness matrix of the annular gyroscope can be obtained as follows:

quadrature coupling nulling and modal frequency matching means:

thus corresponding to the quadrature coupling zero-setting voltage V_tcVoltage V matched with modal frequency_tfSatisfies the following conditions:

cos(θ)sin(θ)(k₁-k₂)＝-16βV_pV_tcD

sin(2θ)(k₁-k₂)＝-16βV_pV_tcD

cos²(θ)k₁+sin²(θ)k₂-4βV_pV_tf(B-A)＝sin²(θ)k₁+cos²(θ)k₂-4βV_pV_tf(A-B)

(cos²(θ)-sin²(θ))(k₁-k₂)＝-8βV_pV_tf(A-B)

cos(2θ)(k₁-k₂)＝-8βV_pV_tf(A-B)

the position of the rigid axis can be back-calculated as:

and in the fourth step, laser balance matching is carried out, and a high-power laser is used for removing a small mass block on the silicon micro-ring gyroscope so that the ring gyroscope can reach a state of complete matching of two modes. In order to ensure the linearity of laser trimming, the width of the removed mass block does not exceed 1/10 of the width of the resonant ring, the length of the removed mass block does not exceed 1/20 of the perimeter of the resonant ring, and the thickness of the removed mass block is equal to the thickness of the resonant ring of the gyroscope. The two completely-matched modes are marked in the way that when the annular gyroscope works under the condition of driving a closed loop, all the orthogonal coupling zero adjusting electrodes and the frequency matching electrodes are grounded, stepping laser trimming is started, and when signals of the two sensitive detection electrodes reach the minimum, the silicon micro-annular gyroscope is considered to reach the intrinsic mode matching state of the mechanical angle at the moment.

In the example shown in FIG. 4, a ring gyroscope with a radius of 2500 μm, a thickness of 120 μm, and a resonant ring width of 40 μm has drive mode and detection mode frequencies of 12477Hz and 12483Hz, respectively, and an initial frequency error of 6 Hz. Passing through V_tc-0.25V and V_tfThe ring gyroscope is adjusted to be in a matching state at 3.85V, the two modal frequencies are 12480Hz, and the rigid spindle position angle is-1.87 degrees after calculation. Next, laser balance matching was completed at four positions, i.e., an angle of-1.87 ° +90 ° n (n is 0 to 3) inside the resonance ring, except for a small mass having a width of 4 μm, a length of 65 μm, and a thickness of 120 μm. And electrifying again to obtain the frequency of the drive mode and the detection mode of the modified annular gyroscope, wherein the frequency of the drive mode and the frequency of the detection mode are both 12460 Hz.