Admittance control for robotic-assisted tele-echography

This paper discusses a new control approach for robotic-assisted tele-echography. An indirect force control (admittance control) establishes the contact dynamics between the echographic probe and the patient, outputting a compliant reference trajectory, used as reference for an inner motion controller. The motion control features computed torque control techniques in joint space, taking into account dynamic and kinematic parameters, as well as stochastic design through active observers (AOBs). Joint space control is driven by task space posture errors converted into joint velocities references. Experiments with a 7-DOF WAM™ manipulator have been carried out, where a human operator teleoperates an ultrasound probe in 6 Cartesian dimensions in typical probe/patient echographic interactions.