Active Damping of Engine Idle Speed Oscillation by Applying Adaptive Pid Control

This paper investigates the use of an adaptive proportional-integral-derivative (APID) controller to reduce a combustion engine crankshaft speed pulsation. Both computer simulations and engine test rig experiments are used to validate the proposed control scheme. The starter/alternator (S/A) is used as the actuator for engine speed control. The S/A is an induction machine. It produces a supplemental torque source to cancel out the fast engine torque variation. This machine is placed on the engine crankshaft. The impact of the slowly varying changes in engine operating conditions is accounted for by adjusting the APID controller parameters on-line.

The APID control scheme tunes the PID controller parameters by using the theory of adaptive interaction. The tuning algorithm determines a set of PID parameters by minimizing an error function. The error function is a weighted combination of the plant states and the required control effort. The tuning procedure is automatic and requires no human intuition or intervention. The algorithm is simple and can be easily implemented on-line as well as off-line. Two versions of the tuning algorithm are presented: the Frechet and approximation methods. They are applied to the problem of engine speed pulsation damping. The approximation method does not require the knowledge of the plant to be controlled; thus, the control scheme becomes robust to plant changes. This type of tuning technique can be applied to a large class of linear and non-linear systems.