Nonlinear active vibration absorber design for flexible structures

A new technique, called active vibration clamping absorber (VCA), for vibration suppression in flexible structures is proposed and investigated in this paper. The technique uses a quadratic-modal-positive-position-feedback (QMPPF) strategy to design a simple second-order nonlinear controller that can suppress the vibration of structures at various resonant points. The proposed QMPPF strategy uses a nonlinear modal control to transfer the vibration energy from the vibrating system to another sacrificial absorber so that large amplitude vibrations in the main structure can be clamped within tolerable limits. The VCA can be constructed using PZT sensors/actuators that are controlled by a DSP controller. The effectiveness of the VCA design based on a QMPPF strategy is validated under multiple-modes control on a flexible vertically-oriented cantilever beam system with a single sensor and actuator. The simulation and experimental results reveal that the proposed strategy is a potentially viable means for real-time control of vibration in large flexible structures.