Modeling & Nonlinear Control for Soft Landing of an Electromechanical Valve Actuator

A considerable amount of research is currently being done on electromechanical valve (EMV) actuators as a potential replacement for the camshaft in order to achieve variable valve timing. Unfortunately, EMV actuators suffer from large impact velocities between the valve, valve seat, and the actuator itself resulting in excessive wear on the system and producing unacceptable levels of noise. Additionally, timing needs to be both quick and consistent to avoid collision with the piston and to reduce variability in trapped mass. In this paper we extend the model developed in our previous work to included impact dynamics and present a nonlinear feedback augmented with an extremal seeking control loop that achieves consistent impact velocities of 0.08 m/s and transition times of 3.2 ms. Corresponding author, e-mail [email protected], Ph: 734-936-0424, Fax: 734-764-4256, Mechanical Engineering Department, University of Michigan, G008 Auto Lab, 1231 Beal Ave., Ann Arbor, MI 48109-4256