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Switching linear parameter-varying electronic throttle control for automotive engines

University of British Columbia

Modern automotive engines are mechanically mature technologies that have been significantly optimized to reduce harmful emissions, reduce fuel consumption, and improve driveablilty. Spark-ignition (SI) engines must operate under a stoichiometric air-to-fuel ratio that allows the three-way catalytic converter to effectively mitigate harmful tail-pipe emissions. Electronic throttle control (ETC) is the primary means of regulating the amount of charge-air entering the cylinders. This research studies the application of switching linear parameter-varying (LPV) feedback control techniques to the ETC problem. Electronic throttle valves are highly nonlinear systems due to their packaging, cost, and reliability constraints. The plant's dynamics vary considerably with respect to slip-stick friction, limp-home springs, and unmodeled disturbances. The complete plant model encapsulates the aforementioned nonlinear dynamics as a linear model that changes affinely with parameter-varying slip-stick friction and voltage fluctuation. The ETC synthesis problem is formulated as a linear matrix inequality as a non-convex optimization problem and solved via iterative methods. In previous literature pertaining to LPV controllers, large variations throughout the electronic throttle valve's operating region have led to conservative results. In this research, to reduce conservatism, the operating region has been partitioned into smaller subregions. Switching events between subregions are based on the scheduling-parameters of the LPV system, which are related to slip-stick friction and voltage fluctuation. The devised switching LPV controller is tuned and validated and its performance is experimentally compared with popular control solutions to the ETC problem. The baseline controllers include classic proportional-integral-derivative control, sliding-mode control, and gain-scheduling LPV control. Experimental results reveal that the switching LPV controller outperforms the baseline controllers throughout all the prescribed operating regions.

Text

2018-04-30

Attribution-NonCommercial-NoDerivs 2.5 Canada

http://hdl.handle.net/2429/55165

Mechanical Engineering

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/2.5/ca/