Nonlinear observer and output feedback design for a combustion engine test bench

Combustion engine control depends strongly on the availability and the quality of the signals involving in the controller construction. In general, not all signals are available through measurement, and therefore an observer is necessary to realize the controller. This paper proposes an observer design for a combustion engine test bench. The observer is used to estimate the torque and the rotation angle of the engine, based on the measurement of the engine and the dynamometer speeds. The convergence of the observer is proved, and separation principle is also shown. The observer is then used to construct an output feedback controller for set point tracking of the test bench. Numerical simulations are performed, showing the performance of the observer and comparing the performance of the output feedback with the state feedback controller. Moreover, the effect of combustion oscillation which causes a vibration noise is taken into account, and the use of internal model based filter to handle the noise is presented.