Papers by Keyword: Micro-Gyroscope

Abstract: Aiming to be applied in silicon gyroscope, a three-order single loop feedforward modulator with three-bit quantizer and local feedback is designed in this paper. Signal band is 200 KHz, sampling rate is 25.6 MHz, OSR is 64. Ideal modulator is then designed and simulated in MATLAB, getting SNR 125dB. Non-ideal factors are also added to ideal model, DWA technology is adopted to restrain the nonlinearity of multi-bit quantizer, getting SNR 104dB. Finally, transistor-level full-difference modulator is designed and simulated in Cadence, fetting SNR 101.3dB.

Abstract: For high-reliability and long-lifetime product, it is difficult to assess the reliability with traditional accelerated life test that record only time to failure. Aiming to solve the problem of the previously, a reliability test and assessment method forecasting the life of samples based on degradation parameter was proposed. According to the working characteristic, the key parameter measuring performance degradation was selected. Based on statistical analysis methods, parameter degradation was designed and parameter degradation model was build. Combined with practical application background, the failure threshold was set and reliability assessment resultwas obtained. The method is applied to assessing reliability of micro gyroscope. The application shows that the method can achieve effective assessment, which can be used as similar products that are difficult to obtain the failure life data in a short time.

Abstract: The thermal analysis and simulation of on-chip temperature control technology in the micro-gyroscope is researched. According to the thermal dissipation mechanism, the thermal resistance model of on-chip temperature control technology is established. The equantions of the conduction thermal resistance and the radiation thermal resistance are deduced. According to the lumped parameter model, the transient thermal response of the proof mass is derived. Theoretical analysis indicates the temperatures of the micro-heater and the proof mass are respectively 136.79°C and 59.95°C in equilibrium conditions. The Ansys simulation model of on-chip temperature control gyroscope is constructed to optimize the transient thermal response and the temperature distribution in steady-state. The simulation results show that the maximum temperature of glass thin-film is about 137.2°C, the temperature of gyroscope structure is about 58.5°C and the temperature difference is within 1°C in the steady-state. In the transient response, the temperature of gyroscope structure can be stabilized in the 12.5s. The simulation results prove that the on-chip temperature technology of micro-gyroscope has an excellent temperature uniformity and rapid temperature response.

Abstract: This paper presents the operational principle, architecture design, resonance characteristics and FEM simulation of a new fully decoupled dual-mass silicon micro-gyroscope. The drive motion and sense motion of the micro-gyroscope studied in this paper are isolated from each other, mechanical quadrature error is thus dramatically suppressed due to the minimizing of undesired coupling between the drive and sense modes. Moreover,two identical single-mass gyroscopes are adopted and coupled with coupling beams to form a dual-mass micro-gyroscope, which provides enhanced common mode rejection in a differential mode. Finally, modal and harmonic analyses are implemented by FEM software, the simulation results obtained verify the good properties of the novel micro-gyroscope.

Abstract: A liquid floating rotational micro-gyroscope is proposed in this paper, whose stability is improved by liquid suspension. High rotor velocity is needed to improve its sensitivity. Edge effect is the phenomenon that sharp edges cause much more viscous drag. This work researches edge effect's influence on viscous drag to speed up the rotor. Flow field models of the sharp edge structure and fillet structure are established separately. Viscous drag is measured by simulation and experiment. Edge effect causes a lot of viscous drag and it can be reduced significantly by filleting the rotor. The maximal reduction is one third relative to the sharp edge structure, and it is reached when fillet curvature radius is half of rotor thickness.

Abstract: In this paper a fourth-order single-loop sigma-delta modulator applied in micro-gyroscope is designed. The modulator system chose the fully feedforword structure. The signal bandwidth is 200KHz, oversampling ratio is 64 and sampling frequency is 25.6MHz. By system simulation result in Matlab, the signal to noise ratio (SNR) is 92.3dB and effective number of bits (ENOB) is 15.03bits. The whole circuit of modulator is designed and simulated in Cadence Spectre. It is gotten that the SNR is 78.6dB and changes linearly with input level. When input level is bigger than -4dBFs, the modulator becomes overload.

Abstract: Despite the popularity of piezoelectric vibratory micro-gyroscope in the past decades for their small size, low cost, batch fabrication and energy efficient, most of them can only detect single axis angular rate. In this paper, a novel biaxial piezoelectric micro-gyroscope fabricated with PZT wafer is proposed. To acquire two-axial angular rate sensing, a bouncing mode of the vibrator is utilized as the drive mode and two rocking modes are used as the sense modes. PZT is used as the vibration body instead of transducer, which enhances the drive and sense efficiency of the sensor. In this paper, the structure and working principle of the novel biaxial piezoelectric micro-gyroscope are introduced firstly. In addition, modal analysis has been made to research the voltage distribution of the piezoelectric vibrator and the drive and sense electrodes of the gyroscope are designed. By the optimization design of the proof mass, the frequency split between the drive mode (bouncing mode) and sense modes (rocking modes) is reduced and the sensitivity of the gyroscope is improved. Harmonic analysis has been made to research the Coriolis Effect of the gyroscope. The data get from the harmonic analysis is demodulated by Matlab and the sensitivity is given. The simulation results verify the principle of the novel biaxial piezoelectric micro-gyroscope. With the optimized design, the sensor is fabricated with MEMS technology at last.

Abstract: The operating performance of micro-gyroscope may be easily influenced by various factors, which changes the dynamic response accordingly. Generally, the influences can’t be quantified because of the complexity, and the accurate sensitivity and linearity measuring of micro-gyroscope meets enormous difficulties. In order to accomplish corresponding measuring and analysis accurately and efficiently, input excitation waves are designed based on mathematical analysis of the measuring principles and vibration response, and each measuring of sensitivity and linearity can be analyzed in a single test. In this way, the influences from manual operation and variation of measuring environment are well eliminated, and some key parameters of the dynamic response are obtained, such as sensitive voltage, response function, linearity error, etc. In addition, problems about imbalance in double drive vibration, design of the minimum excitation voltage and evaluation of the measuring error are also described. Therefore, some important references are provided for subsequent design, experiment and engineering application.

Abstract: For testing angle velocity, testing system of micromechanical gyroscope is applied widely in both military and civil areas, and it is provided with broad foreground of evolution and application, The characteristics of the application require them have high sensitivity and accuracy, under this conditions, technology development level of interface circuit reach their limits, and restricts test performance improvement of the system of micro-gyroscope. In this paper the equivalent electrical model of capacitive micro-gyroscope is established firstly, then a novel interface circuit is designed, the interface circuit include two part, driving-circuit and detecting- circuit, and the feasibility of the driving-circuit and detecting- circuit is emulated and validated by Pspice respectively. The detecting circuit of static state capacitance is come true , and theoretical accuracy of it is 10-18F.

Abstract: Micro-gyroscope is a typical representative of MEMS development, and relative measuring and testing may acquire some important performance parameters, which facilitate analysis and mastery of the operating characteristics further. However, accuracy and reliability of the results or data from measuring system become the key problem for almost all measuring systems. Based on results produced by micro vision measuring, principles about driving and operating of micro-gyroscope are analyzed, and the theory function between input excitation and vibration response is established. With further study on the whole process of dynamic response analysis, resonant amplitude and frequency are finally defined as two decisive factors influencing the accuracy of micro-gyroscope measuring system. Focusing on experiment design and calculation analysis of the two parameters, accuracy and reliability of the system are well verified, which presents important references for other relative measuring systems of micro-gyroscope.