标题: | 具瑕疵补偿与直接角度量测之微机电陀螺仪系统 MEMS Gyroscope Systems with Imperfection Compensations and Direct Angle Measurements |
作者: | 纪建宇 Chi, Chien-Yu 陈宗麟 Chen, Tsung-Lin 机械工程学系 |
关键字: | 微机电振动式陀螺仪;直接角度量测;状态观察器;瑕疵补偿;MEMS vibratory gyroscopes;direct angle measurement;state observer;imperfection compensation |
公开日期: | 2010 |
摘要: | 本研究采用回授控制(软体计算)同时补偿机械结构瑕疵及感测电路瑕疵所造成的影响,在搭配适当的控制与讯号处理方法下,可以不透过角速度积分的方式,直接得到物体转动角度。本论文详细探讨:(1)瑕疵所造成的系统响应在哪些条件下能被正确估测;(2)如何利用控制输入营造出此条件,进而补偿其瑕疵响应;(3)如何由补偿过后的陀螺仪动态直接获得角度资讯。本文设计的控制器可藉由 Lyapunov直接法来证明系统的参数收敛性与系统稳定性。此方法所能补偿的机械结构瑕疵包括因为微结构设计、制程关系所造成的振动质量块质量未知、系统刚性系数未知、系统阻尼系数未知、跨轴动态耦合、感测介面的差分电容对不匹配;感测电路瑕疵包括:寄生电容(Parasitic capacitance)、运算放大器的输入偏压(Offset voltage)、电路杂讯。 本论文所提出的方法亦可与其它状态观察器进行整合,撷取其它状态观察器的优点。在角速度估测的部份,本文利用扩增型卡曼滤波器降低杂讯干扰的能力来提升系统参数与动态估测的品质。在数值模拟印证中,相较于以开路方式操作下的“理想陀螺仪”(无机械结构瑕疵与感测电路瑕疵),本方法可在陀螺仪的所有结构参数都未知(或变动)且感测介面与电路存在瑕疵下,改善感测精确度达六倍;此外,再加入「记忆褪去法」后,对于角速度的感测频宽改善达十倍。在直接角度估测部分,在角速度以200sin(2*pi*10t)°/sec快速变动下,相较于同样条件下以角速度积分的结果,本方法可有效避免误差累积的问题。此外,系统阻尼系数在操作过程因环境变异而出现40%以上的变动时,本方法仍可在0.1秒内完成补偿,并继续角度估算的工作,无须进行离线校正。 In this dissertation, we proposed using control techniques to estimate and compensate the effects from both mechanical structure imperfections and interface circuit imperfections. Accompanied with proper feedback controls and signal processing techniques, the compensated system dynamics can be used to obtain the rotation angle without integrating the angular rates. The mechanical structure imperfections discussed in this report including unknown proof mass, unknown system stiffness, unknown system damping coefficients, undesired cross-axis coupling, and mismatch of the differential capacitive position sensing. The sensing circuit imperfections discussed in this report including parasitic capacitance, offset voltage of a charge amplifier, circuit noise. This dissertation discussed in detail under what conditions that the effect resulting from the imperfections can be correctly estimated. Furthermore, how to create these conditions and compensate those imperfection effects by control inputs. The stability and effectiveness of the proposed method can be theoretically proven by the Lyapunov direct method. The proposed method can work with various existing observer algorithms and benefit from their features. For instance, the extended Kalman filter can estimate system dynamics when the measured signals are noisy. This observer algorithm can be used to work with the proposed method to improve the angular rate estimation accuracy. Comparing to the “open loop” operation method, wherein most of system parameters must be known, simulation results indicated that the proposed method can improve the angular rate sensing accuracy by eight times and the sensing bandwidth by ten times, when those imperfections exist. For the angle measurements, the proposed method does not show obvious signal drifts in a simulation case that the angular rate to be measured is 200sin(2*pi*10t)°/sec. Besides, the simulation results show that the proposed method can sustain sudden system parameter variations (40% damping coefficient variations) without an offline calibration process. |
URI: | http://140.113.39.130/cdrfb3/record/nctu/#GT079314817 http://hdl.handle.net/11536/40529 |
显示于类别: | Thesis |
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