Feedback design air-path control on a diesel engine based on Takagi-Sugeno Fuzzy descriptor systems

In this work a Parallel Distributed Compensation (PDC) Fuzzy controller is applied to regulate the intake and exhaust manifold pressures in a four-cylinder diesel engine with Exhaust Gas Recirculation (EGR). The control strategy implements a feedback controller that generates commands to regulate the mass flow rates and to force two internal variables (pressures) to follow the reference. The PDC-Fuzzy controller is based on a structure of the Takagi-Sugeno (TS) Fuzzy descriptor model, which permits to represent adequately the nonlinear multivariable structure of the process taking into account the constraints on inputs and states. The proposed model is based on a transformation of scalar functions that circumvents the difficulties inherent in the nonlinearity. The PDC-Fuzzy controller is designed using new conditions on Linear Matrix Inequialities (LMI) constraints without invertibility of the Lyapunov matrix to guarantee a robust stability of the diesel engine. The performance of the tracking control strategy is tested in simulations on a four-cylinder diesel engine.