Observer based controller for internal combustion engine

In this work, an observer-based controller for an internal combustion engine is presented. At first, an algorithm for the estimation of an unknown function of the internal combustion engine is designed, since it is very difficult to obtain direct measurements of this variable. This estimator is based on sliding mode algorithms, providing a finite time and robust estimation, using only measurements from the velocity of the engine. On the other hand, with the measured velocity and the estimates of the other variables, a robust controller is synthesized for the engine. In order to considerate the actuator dynamics, the proposed control scheme is based on the master-slave structure, regarding the controller for the actuator as the slave one. For this scheme, the backstepping algorithm is used to design the master controller. Then, the calculated control input signal to the engine is used as a reference for the throttle actuator which is driven by a direct current (DC) motor. Thus, a high-order sliding mode controller is applied to the actuator in order to track the control input signal and reject perturbations, as the applied mechanical load, regulating the velocity of the combustion engine. Numerical simulations show the efficient performance of this proposal.