Observer Based Sliding Mode Control for System with Mismatched Uncertinity

This paper develops observer based a sliding mode control for system with mismatched uncertainties. Most system are affected because of disturbance, modelling uncertainty and their nature being nonlinear. In respect to disturbance, this disturbance can be categorise as matched and mismatched uncertainty. In recent time a lot of focused is given to system which are affected by mismatched uncertainty i.e. disturbance does not enter system through input channel, such system are difficult to control. To improve the robustness and enhance the disturbance attenuation of system which are affected by disturbance which does not satisfy matching condition. One of way to deal with the disturbance is to estimate it then it became simpler to attenuate it and make system performance as per specification. Design procedure consist of two stage, A nonlinear controller is developed which satisfy the performance specification an after that nonlinear disturbance observer is design to estimate the disturbance. The second stage consist of integrating the observer in the design controller with estimation obtain through disturbance observer. It also provide the basics step in designing traditional SMC and Integral SMC and discuss the effect of the disturbance on two method. The performance of proposed approach is validated through simulation. Comparison with the integral sliding mode controller, Nonlinear observer show better response attenuate the disturbance.