Robust feedback linearization using an adaptive PD regulator for a sensorless control of a throttle valve

With classic gasoline injection systems, engine efficiency and emissions are affected by the control of the throttle plate, in particular its angular position. Depending on the current engine load, the angular position must track a trajectory as determined by the accelerator. This paper considers two problems. The first one is the design of a state observer. A velocity estimator is proposed based on measurements of current. If the effect of the noise is minimized, the angular position can be achieved through a cascade structure between a particular velocity estimator and an inversion of the electrical system. This approach allows us to avoid a more complex structure for the observer, and yields an acceptable performance and the elimination of bulky position sensor systems. The elimination of the position sensor system simplifies the production system of the valve. The second problem, the robustness of the tracking, is addressed using a minimum variance control approach. This paper presents feasible real-time self-tuning of an approximated proportional derivative (PD) regulator, which compensates for the tracking error caused by inexact feedback linearization. It is interesting to note that the structure of the approximated PD regulator is similar to the velocity estimator. Robustness in the proposed loop control is achieved. Measured results on a real experimental setup with hardware-in-the-loop are shown. (C) 2009 Elsevier Ltd. All rights reserved.