A new perturbation estimator in a variable structure system with application to robot control

摘要

In this work, a new perturbation estimator using the theory of the variable structure system (VSS) is proposed to enhance control performance of non-linear systems subjected to perturbations such as parameter uncertainties and external disturbances. The proposed estimator is featured by an integrated average value of the imposed perturbation over a certain sampling period. By doing this, undesirable chattering phenomenon in the estimation process can be effectively alleviated. In addition, the proposed method offers a flexibility for tuning the ratio of the perturbation estimation sampling rate to the control input sampling rate. The benefits of the proposed control methodology are demonstrated on a planar robotic manipulator. The position tracking control performances of the manipulator are evaluated and compared between the proposed methodology and conventional scheme for perturbation estimation.