Robust sliding mode controller for turbocharged diesel engine with parameter perturbations

In this paper, the robust sliding mode controller is proposed for the speed control of turbocharged diesel engine. The effect of variation of model parameters on the closed loop performance of the engine is investigated to demonstrate invariance characteristic of the proposed controller. Uncertainties are inserted into both the linearized and the nonlinear model. Uniform uncertainties of plusmn15% are incorporated in each element of the system matrices A and B. In the other case, new set of system matrices are obtained by incorporating the same percent of uncertainties into variables such as eta_i, eta_i, f_mep and DeltaT_e of the original nonlinear model. The same controller parameters are applied for perturbed as well as nominal models. It is shown that, with the sliding mode controller the system remains stable despite such large perturbations in the model. In the second part of this paper, even larger uncertainties to the extent of plusmn20% and plusmn40% are applied to the nominal linear model. The transient response with perturbed models are observed to be significantly deviating from that of the nominal model. It is shown that, despite such large uncertainties, it is possible to shape such transient response by tuning a single controller parameter, which may be seen as tuning a knob.