Feedforward and feedback design for engine idle speed control using l/sub 1/ optimization

In this paper, we present a feedback/feedforward solution for the engine idle speed control problem. The problem formulation and the choice of control structure are motivated from realistic engineering performance requirements and practical implementation considerations. Based on a 4.6 L engine model, we provide an LQG optimal feedback controller to satisfy steady-state tracking requirements and an l/sub 1/ optimal feedforward controller to satisfy transient tracking requirements. The benefits and cost associated with implementing the l/sub 1/ optimal controller are quantified and discussed from both analytical and practical point of view. Simulation results are given to demonstrate the expected performance improvement of the feedforward design.