Robust Cartesian space tracking control of robot manipulators driven by BLDC motors: An observer based partial state feedback approach

This study addresses the end-effector position tracking control of robot manipulators actuated by brushless direct current (BLDC) motors under the constraint that the entire electromechanical system (i.e. kinematic, dynamic, and electrical) contains uncertain parameters, and both joint velocity and Cartesian space velocity measurements are unavailable. Specifically, a partial state feedback controller (requiring phase current measurements of BLDC motors) is presented in conjunction with a novel robust velocity observer formulation that achieves semi-global uniform ultimate boundedness of the Cartesian space position tracking error. The stability of the closed-loop system is ensured via Lyapunov-type arguments. To demonstrate the efficacy of the proposed design, an experimental study is conducted on an in-house developed, two degree of freedom planar robot manipulator driven by BLDC motors.