Silicon MEMS gyroscope bandwidth expanding based on bipole compensation technology
Cao Huiliang;Li Hongsheng;Shen Chong;Liu Jun;Yang Bo;Science and Technology on Electronic Test & Measurement Laboratory,North University of China;School of Instrument Science and Engineering,Southeast University;
The mechanical sensitivity of the silicon MEMS gyroscope structure is inversely proportional to the resonance frequency differenceΔf of the driving and sensing modals. The resonance peak atΔf is the direct factor influencing the gyroscope bandwidth,and usually the bandwidth is about 0. 54Δf. So the mechanical sensitivity and bandwidth become two conflict parameters and trade-off should be considered during structure design. This paper proposes a bandwidth expanding method based on the bipole compensation technique in automatic control theory,which can effectively expand the gyroscope bandwidth without influencing the original mechanical sensitivity,and break the Δf resonance peak( generated by the conjugate poles of the driving and sensing inverse modals) restrict. Firstly,this paper introduces the structure and operation principle of the dual-mass decoupled silicon MEMS gyroscope,and points out that the sensing modal of the gyroscope in real operation is the superposition of the sensing in-phase modal and sensing inverse modal. The gyroscope open-loop sensing circuit is designed; and it is pointed out that the bandwidth is determined by the resonance frequency difference of the driving inverse and sensing the inverse modals. The above conclusion was verified by the sensing feedback force stimulation method( SFFSM). Secondly,the transfer function and circuit of the bipole compensation controller were designed based on the bipole operation principle; and related simulations were conducted,which verifies the accuracy of the circuit parameters. Finally,the silicon MEMS gyroscope close-loop detection system was built based on the bipole compensation controller,the stability of the close-loop system was analyzed. The bandwidth characteristic of the close-loop system was simulated and tested with SFFSM. The results show that the bandwidth is expanded from original 13 Hz to 76 Hz,which proves the feasibility of the proposed method. Furthermore,considering the actual sens-ing modal of the dual-mass decoupled silicon MEMS gyroscope,after eliminating the effect of the first Δf resonance peak on the bandwidth,the amplitude valley caused by the conjugate zeroes generated from the superposition of sensing in-phase and inverse modals is the restrict factor that limits further bandwidth expansion.
【Fund】： 国家杰出青年科学基金(51225504);; 国家973计划(2012CB723404);; 国家自然科学基金委员会和中国工程物理研究院联合基金(U1230114);; 中北大学基金项目资助
【CateGory Index】： TN96
【CateGory Index】： TN96