Control and estimation in force feedback sensors

Abstract

The principle of force feedback is to design a sensor as a feedback system where the action of the measured variable is compensated by a force generated by feedback. Force feedback has contributed significantly to improve the quality of sensors. A characteristic feature of MEMS devices is that they are subject to random disturbances, such as Brownian motion, Johnson-Nyquist noise, and tunneling noise. Variations in device parameters must also be accounted for. In this paper we will discuss principles for designing control and estimation algorithms for instruments based on MEMS devices with force feedback. The fact that the final goal is to design an instrument gives an interesting formulation of the problem. It is shown that shaping of the frequency response can be separated from attenuation of disturbance. The principles have been applied to design of a tunneling accelerometer. The experimental work was done at Professor Turner's laboratory at the University of California, Santa Barbara. © 2011 Springer-Verlag Berlin Heidelberg.