Combining [formula omitted] and resonant control to enable high-bandwidth measurements with a MEMS force sensor

Abstract

We report high-performance control of a MEMS force sensor to provide high-bandwidth reference tracking under uncertain conditions. A key novelty is the implementation of a zero-displacement feedback control system that combines a mixed-sensitivity H∞ controller for setpoint tracking with a resonant controller to augment additional damping to the system. To make the device compatible with various samples, we propose a method to adaptively improve force tracking performance when the force sensor comes into contact with a relatively stiff sample. Performance of the closed-loop system is evaluated by conducting force tracking experiments on two samples with different stiffnesses. The results show that, when operated in closed loop, a resolution of 9.3 nN and a force tracking bandwidth of 1000 Hz can be achieved.