硅微机械陀螺抗寄生电容干扰接口电路与数字化测控电路设计

发布时间：2018-12-17 06:50

【摘要】：本论文针对实验室目前自主研究的硅微机械陀螺做出研究,设计了低噪声抗干扰的接口电路以及数字化测控电路,主要工作如下:首先介绍了硅微机械陀螺仪机械结构及测控电路工作原理,对陀螺驱动闭环与检测开环的工作机理进行推导,并进行误差分析。建立了陀螺寄生电容拓扑,并对寄生电容进行测量,根据测量结果对寄生电容引起的问题进行分析并提出解决方案。基于陀螺工作机理推导、误差分析以及对寄生电容问题的研究,提出了机电接口电路的设计目标,其必须要达到低噪声与抗干扰的要求。针对目前实验室采用的跨阻式接口所存在的不足,提出了三种接口电路改进方案:T型网络接口、积分-微分式接口、两级积分式接口,对三种接口电路的原理进行了介绍,并对其噪声性能与抗干扰性能进行仿真对比。根据对比结果,最终确定采用两级积分式接口,测试结果表明,其等效输入电流噪声为24.3fA/√Hz(@6.4KHz),增益为20.6M,相位误差0.66°,解调相位误差0.44°,并且不受输入杂散电容影响,能够避免高频振荡,满足低噪声与抗干扰要求。然后,对陀螺数字化测控电路进行硬件设计。采用FPGA作为数字平台,通过合理的设计,保证PCB信号完整性。制作完成的电路测试结果表明,模拟部分与数字部分均没有引入额外噪声,保证了接口电路的性能。最后,采用此次设计的接口电路与数字化测控系统对陀螺进行测试,陀螺的标度因数为23.5mV/°/s,标度因数非线性为339.7ppm,角度随机游走为0.011°/√h,零偏不稳定性位0.4°/h,输出速率为10Hz时1σ零偏稳定性为0.78°/h,达到了战术级陀螺的性能要求。
[Abstract]:In this paper, we study the silicon micromachined gyroscope, and design the interface circuit of low noise and anti-interference, as well as the digital measurement and control circuit. The main work is as follows: firstly, the mechanical structure of silicon micromachined gyroscope and the working principle of measurement and control circuit are introduced. The working mechanism of the gyroscope driving closed loop and detecting open loop is deduced, and the error analysis is carried out. The parasitic capacitance topology of gyroscope is established, and the parasitic capacitance is measured. According to the measurement results, the problems caused by parasitic capacitance are analyzed and solutions are put forward. Based on the working mechanism of gyroscope, error analysis and the study of parasitic capacitance, the design goal of electromechanical interface circuit is put forward, which must meet the requirements of low noise and anti-interference. In view of the shortcomings of the transresistive interface used in the laboratory at present, three kinds of interface circuit improvement schemes are put forward: T-type network interface, integral-differential interface, two-stage integral interface. The principle of the three interface circuits is introduced. The noise performance and anti-interference performance are simulated and compared. According to the comparison results, the two-stage integral interface is finally adopted. The test results show that the equivalent input current noise is 24.3fA/ Hz (@ 6.4KHz), the gain is 20.6m, the phase error is 0.66 掳, and the demodulation phase error is 0.44 掳. It can avoid high frequency oscillation and meet the requirements of low noise and anti-interference without the influence of input stray capacitance. Then, the hardware design of gyroscope digital measurement and control circuit is carried out. FPGA is used as the digital platform and the integrity of PCB signal is ensured by reasonable design. The circuit test results show that there is no extra noise in the analog part and the digital part, which ensures the performance of the interface circuit. Finally, the gyroscope is tested by the interface circuit and the digital measurement and control system. The scale factor of the gyro is 23.5mV/ 掳/ s, the scale factor is 339.7 ppm, the angle of random walk is 0.011 掳/ hm ~ (-1), the scale factor is 339.7 ppm, and the angle of the gyro is 0.011 掳/ hm ~ (-1). The zero bias instability position is 0.4 掳/ h, and the 1 蟽 zero bias stability is 0.78 掳/ h when the output rate is 10Hz, which meets the performance requirements of tactical gyroscope.
【学位授予单位】：南京理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TN96

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