Application of a proximate time-optimal controller to an electromechanical throttle

In diesel engined vehicles several electromechanical actuators like butterflies and valves are used to control the gas flow of the engine, e.g. the exhaust gas recirculation. In order to ensure an efficient engine performance regarding pollution, engine power and fuel consumption, high requirements are placed on the positioning accuracy and velocity of the actuator. Concurrently, the maximum possible dynamic of the valve is bounded by the limited power supply. Due to manufacturing tolerances, varying environmental conditions, and aging effects model parameters tend to spread significantly. Thus, a robust controller performance is required as well. In this work a proximate time-optimal controller combined with a disturbance observer and compensation is applied to an electromechanical throttle valve. The nonlinear controller is designed to take full advantages of the limited actuator dynamics for wide range set point changes, whereas the observer suppresses perturbations and unwanted dynamics. The controller performance is investigated experimentally for different parameter setups and environmental temperatures and compared to a pure linear control.