An application of a state-space linearization method to a robot manipulator

An efficient method to design nonlinear controller for robot manipulators, based on state-space linearization concept, is presented. The method consists of three steps: (1) abbreviated equations which approximate the dynamic equations of a manipulator are calculated by Fourier transform; (2) using the simplified equations, linear dynamic equations which are first order approximations of the equations at an operational point, are derived; and (3) nonlinear compensations are designed so that exact linearization of the manipulator's dynamics equations are achieved. The method was applied to a controller design for a direct drive manipulator. The control ability of the system was verified through digital simulations and some experimental results.<>