International Journal of Computer Science Issues

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In this paper, a novel continuous-time robust nonlinear control scheme, is proposed for nonaffine nonlinear systems with unknown uncertainties/disturbance, which is based on backstepping methodology and sliding mode control technique. Firstly, a novel approximation technique is developed to approximate the nonaffine nonlinear dynamic systems. Then, the robust backstepping control for nonaffine nonlinear systems is proposed via the novel approximation technique. In the controller design procedure, the sliding model control method is introduced to avoid the possibility of the over parameterization problem and deal with the unknown uncertainties/disturbance. And, a second-order sliding mode integral filter is employed to facilitate the development of the derivation of the virtual control input with uncertainty terms included. Finally, the designed robust control strategy is applied to three-pole active magnetic bearing system, and simulation results are provided to demonstrate the effectiveness of the theoretic results obtained.