Feed forward disturbance rejection by a multiple FIFO approach for varying system delay compensation

This work is concerned with the increase of the dynamic performance of an engine test bench by suitable combination of a mechanical modification with respect to the standard layout made possible by a new control concept. The improvement of the dynamic performance can be achieved by increasing the stiffness of the connecting shaft between combustion engine and dynamometer. Compared to conventional engine test benches equipped with a standard shaft the torque dynamic with a stiff shaft is a multiple. The torque generation of a combustion engine oscillates with high amplitudes depending on the load request of the driver on the one side, on the other side also the frequency changes in different speed operating points. So heightening the stiffness of the shaft ends always in meeting torque oscillation frequencies as disturbance with the natural eigenfrequency of the engine test bench. Due to the repeatability of combustion cycles a feed forward compensation with time delay compensation of the control loop was implemented.