Variable Admittance Control for HumanRobot Collaboration in RobotAssisted Orthopedic Surgery * In recent days, orthopedic surgical robots play an increasingly important role in surgeries. Impedanceadmittance control is a commonly used method for orthopedic surgical robots. In this paper, we proposed a variable admittance control method for orthopedic surgery. Instead of modifying virtual damping or mass which present in previous variable admittance control works, we present a new method by setting a dynamic reference point for virtual spring to improve operatorsxe2x80x99 boundary control ability during robot assisted orthopedic surgery. The reference point is the mean point of robot end effector trajectory in the past T period. The performance of the proposed controller was tested by conducting a cooperative experience, where all subjects were asked to finish a reaching task by using a Minirobot.

MultiSurface Admittance Control Approach applied on Robotic Assembly of LargeScale parts in Aerospace Manufacturing The robotization of assembly operations is one of the requests of aircraft manufacturers. During the assembly of largescale subassemblies, contact forces between parts must be controlled. Exceeding some limits can damage the aircraft parts. This can happen because of the poor accuracy of industrial robots and uncertainties of partsu0027 positions, and orientations. This paper proposes a new approach to control the movement of the robot endeffector, taking into account the contact forces between the parts during assembly. The suggested approach can be used to assemble complex shape and largescale parts. Based on the admittance control, the proposed approach is used to ensure multisurface contact. It allows to control the interaction forces at each contact surface. Each contact is modeled by a massspringdamper system. This approach was tested on the assembly of two largescale airplaneu0027s parts using a KUKA robot (KR340), equipped with a ForceTorque (FT) sensor. The performance of this multisurface approach was compared to one surface admittance control.