An expository overview of active control of machinery mounts

The author considers the isolation of vibration originating in a comparatively compact, rigid machine. The machine can be an internal combustion engine, a turbine, compressor, etc. The machine is mounted in a structurally flexible vehicle using several machinery mounts. A machinery mount should be capable of transmitting low-frequency forces and supporting the machine against static loads due to vehicle accelerations but incapable of transmitting high frequency vibratory force. Past approaches have been passive, involving `soft springs´ and, occasionally, dynamic effects. Advances in electronics, materials and to a lesser degree control theory, suggest the possibility of accomplishing these tasks more effectively with active or combined active/passive techniques. The author attempts an overview and classification of the problem and of potential active approaches