Motion control of an electromagnetic valve actuator based on the inverse system method

In an electromagnetic valve actuator (EMVA), precise motion control is desired to achieve fully variable valve actuation, so that the fuel economy, the emissions, and the torque output performance of the engine will be improved. This paper presents an inverse system method (ISM) to achieve precise valve motion control for a moving-coil EMVA. The dynamic model of the EMVA is established, and the inverse system of the EMVA is obtained. By linearization of the non-linear EMVA system, state feedback control is used to control the valve to follow the desired valve motion. A state variable observer is designed to estimate the unmeasurable state variables. Simulations and an experimental set-up are used to demonstrate the effectiveness of the proposed control method. The performance of proportional–integral–derivative control is compared with ISM control in the simulations, and ISM control is robust to large parameter variations of 50 per cent. The experimental results show close agreement with the simulation results. The proposed method proved effective by achieving a transition time of 3.8 ms and a seating velocity of 0.05 m/s. Fully variable valve actuation has been achieved and the valve motion profile is given.