硅微陀螺机电结合带通Sigma-delta闭环检测方法研究

发布时间：2018-04-24 19:43

本文选题：硅微陀螺仪 + 机电结合　；参考：《南京理工大学》2017年硕士论文

【摘要】：硅微陀螺仪(SMG)是一种利用哥氏效应来检测物体角速度的惯性器件,广泛应用于姿态定位、导航控制等领域。在硅微陀螺的检测电路研究方面,基于带通Sigma-delta调制器(SDM)所设计的闭环检测电路可以使陀螺具有数字化输出并且有效抑制带宽内的量化噪声,而且闭环的特性可以有效消除机械加工误差带来的检测输出误差、提高闭环检测环路带宽,是目前国内外很多相关机构研究的热点。因为其SDM环路难以明确、环路参数难以获取,而国外对此研究比较成熟的机构又对相关技术进行保密,因此有必要对硅微陀螺机电结合带通SDM闭环检测方法有一个比较深入的研究,对此本文作了以下工作。首先对Sigma-delta调制器的基本原理进行了研究,针对陀螺的结构形式对SDM环路结构进行了初步选择,放弃了级联和多位量化的方式,选择了单环和一位量化的方式来设计整个闭环检测电路。其次从陀螺敏感结构的离散化形式入手,对各种可行的离散时间SDM环路结构进行了理论分析,得出单环CRFF结构是建立硅微陀螺机电结合带通SDM闭环检测环路最为理想的结构。再根据陀螺结构的的具体参数,以带通、带宽、量程、分辨率等为约束条件,结合离散时间SDM设计工具Dstoolbox,获取了适用于陀螺的离散时间SDM闭环结构的环路参数。最终利用等价设计的原则完成了从离散时间SDM到机电结合SDM的转换,建立了一套完整的机电结合带通SDM闭环检测环路的设计流程。然后针对陀螺具体的结构和参数将整个机电结合带通SDM闭环检测环路从功能上进行了分解以及对环路参数进行了调整,并在Simulink中进行了仿真,验证了方案的可行性,对后续硬件电路的实现提供了设计基础。最后进行了基于Sigma-delta的陀螺闭环检测电路的设计和实验验证,包括硬件电路的设计与制板,FPGA中的Verilog代码的编写以及实验的调试、观测与数据的采集,并对所获取的闭环结构和参数在实际硬件中进行了验证。最终通过对一位量化输出结果进行功率谱密度(PSD)分析,可以看到所设计的陀螺机电结合SDM闭环检测电路具有明显的噪声整形功能,在信号带宽处量化噪声被抑制,测试结果显示在带宽内的噪声水平约为-70dBV/Hz1/2到-80dBV/Hz1/2。满幅量程200°/s输入的时候,一位量化输出信噪比约为70dB,有效位数约为11.33位。
[Abstract]:Silicon microgyroscope (SMG) is a kind of inertial device which uses the Coriolis effect to detect the angular velocity of the object. It is widely used in the field of attitude positioning, navigation control and so on. In the aspect of detecting circuit of silicon microgyro, the closed-loop detection circuit based on band-pass Sigma-delta modulator can make gyroscope have digital output and restrain quantized noise in bandwidth effectively. Moreover, the characteristics of the closed-loop can effectively eliminate the detection output errors caused by machining errors, and improve the bandwidth of the closed-loop detection loop, which is a hot research topic of many related institutions at home and abroad. Because the SDM loop is difficult to define and the loop parameters are difficult to obtain, the relevant technology is kept secret by the foreign organizations which are more mature in the research. Therefore, it is necessary to have a deep research on the electromechanical band-pass SDM closed-loop detection method of silicon micro gyroscope. The following work has been done in this paper. Firstly, the basic principle of Sigma-delta modulator is studied, and the structure of SDM loop is preliminarily selected according to the structure of gyroscope, and the cascade and multi-bit quantization methods are abandoned. The single loop and one-bit quantization method are selected to design the whole closed-loop detection circuit. Secondly, starting with the discrete form of gyroscope sensitive structure, this paper makes a theoretical analysis of various feasible discrete time SDM loop structures. It is concluded that the single ring CRFF structure is the most ideal structure for establishing the silicon micro gyroscope electromechanical combined with bandpass SDM closed loop detection loop. According to the specific parameters of gyroscope structure, the loop parameters of discrete-time SDM closed-loop structure for gyroscope are obtained by taking bandpass, bandwidth, measurement range and resolution as constraint conditions, combined with the discrete time SDM design tool Dstoolbox. Finally, the conversion from discrete time SDM to electromechanical combined SDM is completed by using the principle of equivalent design, and a complete design flow of closed loop detection loop of electromechanical band-pass SDM is established. Then according to the structure and parameters of gyroscope, the whole electromechanical band-pass SDM closed-loop detection loop is decomposed in function and the loop parameters are adjusted, and the simulation in Simulink is carried out to verify the feasibility of the scheme. It provides the design basis for the implementation of the subsequent hardware circuit. Finally, the design and experimental verification of gyroscope closed-loop detection circuit based on Sigma-delta are carried out, including the design of hardware circuit, the preparation of Verilog code in board making FPGA, the debugging of experiment, the observation and data acquisition. The closed-loop structure and parameters obtained are verified in actual hardware. Finally, by analyzing the output result of one bit quantization, we can see that the gyroscope electromechanical combined with SDM closed-loop detection circuit has obvious noise shaping function, and the quantization noise is suppressed at the signal bandwidth. The test results show that the noise levels in the bandwidth range from -70 dBV / Hz1 / 2 to -80 dBV / Hz1 / 2. When the full amplitude range is 200 掳/ s input, the signal-to-noise ratio (SNR) of one bit quantization output is about 70 dB and the effective bit number is about 11.33 bits.
【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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