Control of a moving oscillator on an elastic continuum using smart dampers

This paper considers the use of active and semiactive control techniques to reduce the dynamic response of an elastic continuum that is excited by a moving oscillator. This system is often referred as the "moving-oscillator" problem. A series expansion is used to model the continuum, resulting in a time-varying, linear model describing the dynamics of the coupled system. The control devices are assumed to be ideal (neglecting actuator dynamics), and are placed in parallel with spring and dashpot elements that represent the suspension of the oscillator. Three different control designs are applied and compared in terms of their ability to reduce the dynamic response of the continuum and the oscillator: active, passive and semiactive. An LQG control algorithm that uses accelerations of the continuum for feedback is used to calculate the optimal gains (in the active case) and the velocities at every point (for the semiactive case). The results indicate that the system responses with the semiactive controller approach those of the active system, while the semiactive device uses significantly less power. Both cases outperform the passive control system.