Hybrid Controller for Vibration Suppression: Integrating Physical and Modal Information Using Fuzzy Reasoning

Abstract

Independent Modal space Control (IMSC) is a well established method in active control of vibration. In this method, the control law is developed exclusively in the modal space, allowing for independent design of modal control forces. These forces are then transformed to the physical space by modal transformation. The resulting controller is fixed-gain, with the active damping introduced to the system determined independently for each mode. This damping is directly proportional to the modal velocity in the under-damped case. In this work, we propose to modify IMSC using kinetic energy distribution in the modal space, and fuzzy reasoning. The result is a new non-linear control law, embedding fuzzy reasoning and an implicit fuzzy rule-base that transforms the standard algorithm from a fixed-gain, to a variable-gain controller. A variant of the new algorithm uses information about the velocity profile across the sensed locations to distribute the active damping rationally among the modal controllers. This new algorithm complements the local view of the traditional algorithm in the modal space, with a global view of the velocities in the physical space. The results show significant improvement in the settling time as the performance criterion.