Experimental comparison of model-based robot position control strategies

An experimental comparison of model-based joint space position control (JSPC) and Cartesian space position control (CSPC) strategies for the same manipulator, trajectory, sample rate, and dynamic model is presented. It is shown that the achievable tracking performance (in terms of the peak tracking error) and disturbance rejection capability of JSPC was experimentally better than that of CSPC for the same sample rate. High feedback gains for CSPC were found to be unachievable, which the authors suggest is due to the incompatibility between actuation and control space. The effect of varying the trajectory velocity, and of using a diagonal or full mass matrix in the control torque computation on the performance of the both strategies is also presented.