Hongyin Li^1,2, Yanzheng Bai¹, Ming Hu³, Yingxin Luo⁴ and Zebing Zhou^1,*
1 MOE Key Laboratory of Fundamental Quantities Measurement, School of Physics, Huazhong University of Science and Technology (HUST), Wuhan 430074, China; hongyin83li@hust.edu.cn (H.L.); abai@mail.hust.edu.cn (Y.B)
2 School of Automation, Huazhong University of Science and Technology (HUST),Wuhan 430074, China
3 Institute of Geodesy and Geophysics, Chinese Academy of Science, Wuhan 430077, China; huming@whigg.ac.cn
4 Tianqin Research Center for Gravitational Physics, School of Physics and Astronomy, Sun Yat-sen University, Zhuhai 519082, China; luoyx43@mail.sysu.edu.cn
* Correspondence: zhouzb@hust.edu.cn; Tel.: +86-27-8754-2391
Academic Editor: Vittorio M. N. Passaro
Received: 1 November 2016; Accepted: 20 December 2016; Published: 23 December 2016

Abstract: The state-of-the-art accelerometer technology has been widely applied in space missions. The performance of the next generation accelerometer in future geodesic satellites is pushed to 8x10^-13 m/s²/Hz^1/2, which is close to the hardware fundamental limit. According to the instrument noise budget, the geodesic test mass must be kept in the center of the accelerometer within the bounds of 56 pm/Hz^1/2 by the feedback controller. The unprecedented control requirements and necessity for the integration of calibration functions calls for a new type of control scheme with more flexibility and robustness. A novel digital controller design for the next generation electrostatic accelerometers based on disturbance observation and rejection with the well-studied Embedded Model Control (EMC) methodology is presented. The parameters are optimized automatically using a non-smooth optimization toolbox and setting a weighted H-infinity norm as the target. The precise frequency performance requirement of the accelerometer is well met during the batch auto-tuning, and a series of controllers for multiple working modes is generated. Simulation results show that the novel controller could obtain not only better disturbance rejection performance than the traditional Proportional Integral Derivative (PID) controllers, but also new instrument functions, including: easier tuning procedure, separation of measurement and control bandwidth and smooth control parameter switching.

Sensors 2017, 17, 21; doi:10.3390/s17010021