Design, Manufacturing and Control of an Advanced High-Precision Robotic System for Microsurgery

Microsurgeries like ophthalmic surgery confront many challenges like limited workspace and hand motion, steady hand movements, manipulating delicate thin tissues, and holding the instrument in place for a long time. New developments in robotically-assisted surgery can highly benefits this field and facilitate those complicated surgeries. Robotic eye surgery can save time, reduce surgical complications and inspire more delicate surgical procedures that cannot be done currently by surgeon’s hands. In this thesis work, the requirements for ophthalmic surgeries were studied and based on that a robotic system with 6 DOF is proposed and designed. This robotic system is capable of handling the position and orientation of the surgical instrument with theoretical accuracy of 10 μm. The design features a remote center of motion that defines the point of entry into the eye or patient’s body. The forward and inverse kinematics equations and workspace analysis of the robot is also discussed and presented. Six miniature DC motors with their PID controllers were installed on robot arms in order to run 6 DOF systems. Therefore, the dynamic behavior of a DC motor was studied and modeled and then the position and velocity transfer functions were derived and used to study the behavior of the system and also to manually tune the PID controller. The function of different elements of the control system including encoder, controller modules, Controller Area Network (CAN) and the controller software were discussed as well. The graphical user interface called EPOS Studio and performs as the motion controller is introduced and the way it organizes communications among the elements of the control system was described