Keywords : uncertainty
IRAQI JOURNAL OF COMPUTERS, COMMUNICATIONS, CONTROL AND SYSTEMS ENGINEERING,
2012, Volume 12, Issue 2, Pages 81-89
In this paper, a controller design is proposed to control systems subjected to uncertainties and perturbed time-varying delay. The proposed controller strategy is composed of three parts, the linear state feedback part is used for assigning the closed loop eigenvalues, and the nonlinear switching part of the sliding mode and the adaptive part are used to achieve the robustness of global stability. By using the stability theorem, the adaptive law is utilized for adapting the unknown bounds of the lumped perturbations so that the objective of asymptotical stability is achieved, and then to use the variable structure control method to enhance the robustness of stability of the controlled systems. Once the system goes inside of the sliding surface of the variable structure controller, the dynamics of the controlled systems are insensitive to effect of perturbations. The system and controller are simulated by using Matlab/Simulink. Finally, a real numerical example is given to demonstrate the feasibility of the proposed controller.