MIMO 비선형시스템에 대한 전체 추종오차 구속 비선형 확장 상태관측기를 갖는 Supertwisting 백스테핑 제어

Abstract

In this paper, a supertwisting algorithm (STA) based backstepping control (BSC) for multiple-input and multiple-output nonlinear strict-feedback systems with a nonlinear extended state observer (EOB) and full tracking error constraint control is presented. The output and the virtual tracking errors were included in new state variables defined in the concept of the STA used to design virtual stabilizing controls and final controllers in the recursive BSC design procedures. Unknown uncertainties resulting from dynamic perturbation and external disturbance were estimated using an EOB to obtain better estimation performance than that of the conventional nonlinear disturbance observer. Thus, combining the STA and EOB systems, we found that the designed STA-BSC system inherited the finite-time tracking performance and robustness from the conventional BSC systems, which were designed on the basis of an infinite-time convergence concept. Moreover, the full tracking error constraint control method, as an extended version of the output tracking error constraint control, is presented to ensure that all the tracking errors are within the prescribed boundaries. The proposed control scheme was verified through simulated applications to a robot manipulator system.