Contact Force Control on Soft Membrane for an Ear Surgical Device

Abstract

Mechatronic and robotic systems are increasingly used in the health care and medical industry in recent years. Once the surgery is shifted from operating room to clinic or surgeon's office by using an office-based surgical device, the patient cannot be administered general anesthesia and thus the patient's motion can affect the performance of such a surgical device and even the success of the surgery. For an office-based ear surgical device designed to insert a tube on the tympanic membrane, the patient's head motion will affect the success rate of tube insertion. To address this issue without adding any extra equipment, a head motion compensation system based on contact force control is developed in this paper. A model describing the displacement–force relationship of the soft membrane is built based on viscoelastic behavior and contact effect. Based on the model, a proportional-integral-derivative controller obtained via constrained linear-quadratic optimization algorithm and a disturbance observer are designed. Finally, several experiments for system performance validation are conducted on a mock-up system, whose results show that the optimal force controller can perform a good set-point tracking ability. Meanwhile, the proposed control scheme can compensate the motion and achieve an accurate and steady contact force control.