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Mathematical Problems in Engineering
Volume 2014, Article ID 950768, 11 pages
http://dx.doi.org/10.1155/2014/950768
Research Article

Time-Varying Integral Adaptive Sliding Mode Control for the Large Erecting System

Xi’an High Technology Research Institute, Xi’an 710025, China

Received 22 May 2014; Revised 28 August 2014; Accepted 28 August 2014; Published 29 September 2014

Academic Editor: Chunlin Chen

Copyright © 2014 Xie Zheng et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Considering the nonlinearities, uncertainties of large erecting system, and the circumstance disturbances in erecting process, a novel sliding mode control strategy is proposed in this research. The proposed control strategy establishes the sliding mode without reaching phase using an integral sliding surface. Thus, robustness against uncertainties increases from the very beginning of the process. Furthermore, adaptive laws are used for the controller to estimate the unknown but bounded system uncertainties. Therefore, the upper bounds of the system uncertainties are not required to be known in advance. Then, the time-varying term is applied to ensure the global robustness. Moreover, the boundary layer method is used to attenuate the high frequency chattering. The experiment results demonstrated that the proposed strategy could effectively restrain parametric uncertainties and external disturbances and improve the tracking accuracy in the erecting process. In addition, the control performance of the proposed control strategy is better than that of the PID control and the conventional sliding mode control.