An improved perturbation attenuation method for motion control of robotic systems

A new perturbation attenuation method is proposed for motion control of robotic systems. It effectively attenuates all the perturbation to the joint dynamics of a plant including inertial cross coupling force, nonlinear friction, and external disturbances. As a result, it achieves a decentralized control system. A remarkable feature of the algorithm is that it has multiloop structure which can hierarchically compensate the "residual perturbation." An inherent property of the recursive algorithm which enables to overcome the limit of existing perturbation observers is described through the stability/performance analysis. Experimental results on the 2 DOF direct drive arm verifies the effectiveness of the proposed perturbation compensator.