Control of an electromechanical camless valve actuator

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