Control of an electromechanical camless valve actuator

This paper addresses modeling analysis and the soft seating control of an electromagnetic actuator used in electromechanical camless valvetrains. Our mathematical modeling analysis reveals the instability of the actuator dynamics linearized around the seating position and zero velocity. This implies that open loop pulse shaping alone cannot render repeatable valve closing and seating motion. Closed loop feedback control is necessary to generate repeatable motion that is insensitive to disturbances. A linear model is constructed based on gray-box approach that combines mathematical modeling and system identification. Notch filtering and linear quadratic optimal control is designed and experimentally tested. Control performance is evaluated in terms of closing time, valve seating velocity and seating tail-length, armature crossing velocity and armature seating velocity.