Vibration suppression in rotating beams using active modal control

Advances in technology and the underlying demand for achieving high performance has resulted in a class of light-weight high-speed mechanical systems. Light-weight mechanical components are prone to appreciable elastic deformations and experience vibrational motions. Vibration suppression in rotating elastic members is of major importance in many engineering applications. Examples are robot manipulators, propellers, turbomachines, high-speed flexible mechanisms, and space deployable systems. Active control falls among the most feasible techniques for vibration suppression in rotating structures, where passive techniques may become ineffective or impractical. The vibrational motion of the rotating elastic member is represented by a finite element dynamic model, which is written in terms of a reduced set of modal co-ordinates. A realistic set of modal co-ordinates that accounts for the dynamically induced stiffening effect due to reference rotation is introduced. Pointwise observation and control are employed in association with an optimal state-variable feedback strategy. The control scheme developed is applied to a rotating beam, and the dynamic responses of both the controlled and residual frequency subsystems are numerically evaluated.