Output tracking in first-order time-delay systems: A dynamic control approach

Output tracking of systems, which are represented through a surrogate first-order model with a delay in the control input, is examined in this paper. A dynamic control input is proposed to maintain the system output to track a desired reference profile, while providing closed-loop stability. The system closed-loop response is demonstrated for fueling control in lean-burn gasoline spark ignition engines addressing the varying transport and combustion delays. The developed methodology, which is validated on a Ford F-150 SI lean-burn engine model with large time-varying delay in the control loop, exhibits improved performance in terms of disturbance attenuation, measurement noise accommodation and robustness against delay estimation anomalies. The proposed controller is compared with a PI controller equipped with a Smith predictor and the results are discussed for various operating conditions.