A nonlinear PI controller for optical tweezers system

Positioning an optical tweezer is a complex task due to the inherent nonlinear characteristic of the process and the multiple disturbances that affect its behavior. In this work, a nonlinear PID controller is proposed to address the challenges posed by this task. The control scheme is designed to minimize the effect of uncertainties and external forces that perturb the system. The stability of the closed loop system is analyzed by using standard Lypaunov theory. Some numerical simulations illustrate the robustness of the proposed control scheme under random thermal and constant perturbations.