Reliability Enhancement of MEMS Lateral Comb Resonators Under Fault Conditions

The delicate structure of microelectromechanical systems (MEMS) limits their reliability in cases of fault occurrence. Control systems can enhance their reliability of operation by providing fault robust systems. This paper illustrates a method for the safe operation of lateral comb resonators (LCR) under faulty conditions. Different types of fault are fabricated at chip level and experimentally tested in order to demonstrate the effectiveness of the reliability enhancement of operation in LCRs. Mass change and folded spring structural defects influence the device´s behavior and reduce its reliability of operation. Here, model reference adaptive controllers (MRACs) are effectively used to enhance the reliability of faulty devices. Reliable operation of a +5% additional mass considering environmental conditions and asymmetries on the device, demand almost 80% higher control effort whereas +20% in case of broken trusses or +46% in case of adhesion point fault on a beam of folded springs. The simulation and experiment results demonstrate successful application of MRAC for reliable operation of LCRs by providing a fault-robust system.