Model based feed-forward control of electromagnetic type active control engine-mount system

This paper introduces a low-cost prototype active control engine mount (ACM) designed for commercial passenger vehicles, requiring a good engine vibration isolation performance. To construct such an ACM system, all feedback sensors normally required for full ACM systems are replaced by the model based feed forward algorithm, consisting of a vibration estimation algorithm, a current shaping controller and an enhanced ACM model. The ACM model describes the active as well as passive characteristics of ACM. The current shaping control compensates for degradation of control performance due to elimination of feedback control sensors. The engine vibration estimator, which uses such existing sensors as CAM and crank angle sensor (CAS), replaces a sensor to monitor the transmitted vibrations from the engine to the chassis. The validity of the ACM model is experimentally verified so that it accurately predicts the dynamic behaviors of the ACM over the frequency range of interest. The proposed current shaping control improves the actuator control performance, and the vibration estimation algorithm provides the anti-vibration signals for vibration isolation. Finally, it is experimentally proved that the vibration isolation performance of the developed ACM for the engine-induced vibration of interest can be improved by more than 13 dB.