This paper presents closed loop simulation of a CMOS-MEMS force sensor for biomedical
applications employing an optimal proportional-integral-derivative controller. Since the
dynamic behavior of the sensor under investigation is nonlinear the iterative feedback
tuning approach was proposed for optimal gains tuning of the proposed controller.
Simulation results presented in this research illustrate that the proposed controller
suppresses the undesired in-plane vibration induced by environment or gripper 40 times
faster than the nonlinear controller proposed in the literature. To suppress the maximum
input disturbance the maximum voltage was approximately 18 V which was less than the
pull-in voltage of 30 V. The proposed controller is served to actuate two stator fingers
adjacent to a rotor finger in order to provide both the attractive and repellent forces
during manipulation. Employing the proposed mechanism not only resolves the drawbacks
corresponding to the nonlinear controller presented in the literature but also improves
its performance of the closed loop system by using the complete nonlinear dynamics of the
force sensor. Also, applying complete non-linear dynamic of model improves the performance
of controller and is one of superior features of proposed PID controller in comparison
with the classical controller presented in literature.