This paper presents a methodology to synthesize robot compliant motions in environments that can move or oscillate due to random disturbances. Motions of the environment are taken into account in the task frame position which is considered unknown and time-varying but bounded. The position, velocity and force responses of the coupled robot/environment system are determined and tasks are expressed as inequality constraints on these expressions. A set of controller parameters is found by fitting the largest possible uncertainty box inside the region of the impedance parameter space that satisfies all task constraints. Experimental results demonstrate the validity and robustness of the approach.

An adaptive motion control scheme for robotic manipulators is presented. This is an adaptive computed torque method (CTM) that requires only position measurements. These measurements and the input torques are used in an extended Kalman filter (EKF) to estimate the inertial parameter of the full nonlinear robot model as well as the joint positions and velocities. These estimates are used by the CTM to generate the input torques. This combination of the EKF and the CTM was shown to result in a stable adaptive control scheme. Experimental results with a two-degree-of-freedom direct-drive robot illustrate the performance of this scheme.>