Design of a Capacitive based Closed-Loop Displacement Sensor

The starting concept is decomposed into system elements which have one function. For each system element a model is created that describes the behaviour of the element. Each system element model is than developed into a physical part of a MEMS system. During development the place on the structure and available space are closely monitored. Each part is designed for optimal resolution. The next step is to put all the physical MEMS parts together into a complete MEMS structure. With the MEMS structure defined, the last piece of the system can be designed. The controller is also the most essential part of the system because the MEMS structure itself is unstable during operation. The controller provides stability to the structure and is therefore very important. Bandwidth and stability are carefully balanced during the design of the controller.