Iterative learning control for soft landing of electromechanical valve actuator in camless engines

Variable valve timing allows improvements of internal combustion engines and can be achieved by camless actuation technology. In this paper we consider an electromechanical valve (EMV) actuator. One of the main problems in the EMV actuator is the noise and wear associated with high contact velocities during the closing and opening of the valve. The contact velocity of the actuator parts can be reduced by designing a tracking controller that consists of a linear feedback and a nonsquare iterative learning controller (ILC). With the ILC methodology we update the feedforward signal of the feedback controller every cycle based on the error between the actual valve position and the desired position. The methodology is reviewed and both simulation and experimental results are presented. We explore the disturbance rejection capability of the control scheme by simulating conditions with an unknown force acting on the valve similar to the ones present during varying engine load.