Dynamic, output-feedback, gain-scheduling control of an electric variable valve timing system

In this paper, a discrete-time, linear parameter-varying (LPV) system representing the electric variable valve timing (VVT) system is developed with engine oil viscosity as the time-varying parameter. A gain-scheduled, dynamic, output-feedback controller is then designed such that the closed-loop system will have a guaranteed ℓ₂ to ℓ_∞ gain, which is very closely related to the physical performance hard constraints. This is done by first constructing a set of linear matrix inequality constraints and then performing a convex optimization to obtain the controller matrices which satisfy the constraints. Simulation study results demonstrate the effectiveness of the proposed scheme.