Safety design of an Assisting Robotic Arm for minimally invasive thoracic surgery

Based on the analysis of the first prototype of an assisting robotic arm (ARA) for minimally invasive thoracic surgery, an improved design is presented. A self-gravity compensation mechanism is developed to resist joint torques caused by the weight of the robot and to reduce the force exerted on the end-effector by the surgeon. With a motor built into the arm, the design of the ball-socket-joint is modified to widen the surgeon´s field of view. The current pedal brake is replaced with an operating pushbutton to avoid maloperation. A control system for the improved ARA is developed. The experimental results show that the workspace and the locking torque can satisfy the basic requirements of a surgery.