Model free force/position robot control with prescribed performance

In this paper, we consider the force/position tracking problem for a robot in compliant contact with a kinematically known planar surface. We propose a novel controller that achieves predefined performance indices regarding the transient and steady state response of the robot force/position tracking errors and ensures no loss of contact of the robot-end effector. The proposed controller is model free in the sense that it does not incorporate any information regarding either the robot dynamic model or the force deformation model. Moreover, the controller gains are easily selected since the only concern is to adjust them to yield reasonable input torques. Simulation results on a 3-DOF robot confirm the theoretical findings.