Analysis of powertrain motions given a combination of active and passive isolators

Most of the prior work on active mounting systems has been conducted in the context of a single degree-of-freedom even though the vehicle powertrain is a six degree-of-freedom isolation system. We seek to overcome this deficiency by proposing a new analytical model that will examine a combination of active and passive mounts. The chief objective of this article is to investigate the complex eigensolutions and frequency responses of the active powertrain system when excited by an oscillating torque. A typical analytical model for displacement type active mounts is developed in the form of transfer functions that relate the transmitted force through the mount to both driving point motion and active displacement terms. Given this model, passive path characteristics are identified in the form of eigenstructure. Then, the role of active path is clarified by comparison with no active operation. Multi-dimensional motions (especially coupling) are predicted and in particular the effects of active mount parameters such as the orientation angle, location and actuator input are investigated from the motion coupling perspective.