Title

Tunable torsional vibration absorber: The centrifugal delayed resonator

Date of Completion

January 1997

Keywords

Applied Mechanics|Engineering, Mechanical

Degree

Ph.D.

Abstract

A novel active vibration absorption technology, the Centrifugal Delayed Resonator (CDR), is presented as an efficient method for eliminating undesired torsional oscillations in rotating mechanical structures. The core idea is to reconfigure the dynamics of a damped centrifugal pendulum arrangement so that it behaves like an ideal real-time tunable absorber. This objective is achieved by applying a control torque based on proportional position feedback with variable gain and time delay.^ A general mathematical model of a rotating mechanical structure with the CDR absorber is developed. Fundamentals of the control strategy and its basic properties are explained. Effects of the CDR absorber on a single-degree-of-freedom and a multi-degree-of-freedom rotating structure are studied. A thorough stability analysis for the controlled system is presented. Various considerations related to practical implementation of the CDR are also discussed. Finally, a proof-of-concept prototype is designed and representative results of laboratory tests are presented.^ The strengths of the CDR vibration control technology consist in complete elimination of a fundamental frequency component of torsional oscillations at the location where the absorber is attached to the rotating structure, full effectiveness of vibration suppression in problems where the fundamental frequency of oscillations varies with time, very wide range of operating frequencies, complete decoupling of the feedback control from the mechanical properties of the rotating structure, comparatively simple implementation of the control algorithm, and fault-tolerant performance in the case of control failure. ^