Position/force control of uncertain constrained flexible joint robots

This paper addresses the issue of adaptive position/force control of uncertain constrained flexible joint robots (FJRs). The controller is developed without the assumptions of weak robot joint flexibility as adopted in popular singular perturbation (SP) approaches. It relies on the feedback of joint state variables and avoids noisy joint torque measurements found in most controllers developed so far. In addition to the robot inertia parameters, the joint stiffness and the motor inertia are also assumed to be unknown. The proposed approach achieves the position tracking and the boundedness of force errors. The simulation study is conducted to verify the effectiveness of the approach.