robust fractional order control of under-actuated electromechanical system

this paper presents a robust fractional order controller for flexible-joint electrically driven robots under imperfect transformation of control space. the proposed approach is free from manipulator dynamics, thus free from problems associated with torque control strategy in the design and implementation. as a result, the proposed controller is simple, fast response and superior to the torque control approaches. it can guarantee robustness of control system to both structured and unstructured uncertainties associated with robot dynamics. the control method is verified by stability analysis. simulation results on a two-link actuated flexible-joint robot show the effectiveness of the proposed control approach.