Active Vibration Control Using Modal Techniques

Abstract

By aligning the coordinates of the control algorithm with the modal coordinates of the flexible structure being controlled, Independent Modal Space Control (IMSC) uses the orthogonality of the mode shapes to minimize the computational requirements of control systems. With an objective of minimizing settling time, a comparison is made of several vibration control algorithms, which use IMSC theory. For optimal control, this paper presents an incremental search technique to estimate the preferred R values for a given set of initial conditions. Modified Independent Modal Space Control (MISMC) utilizes a time sharing strategy to share a small number of actuators between a greater number of modes. This technique produced discontinuities in the actuator forces which results in spillover and reduces its effectiveness. The Total Independent Modal Space Control (TIMSC) method, introduced in this paper, avoids significant force discontinuities by using all the available modal information. Additional (non-optimal) comparisons include a method for varying R values during the control process, and also control strategies involving actuator force saturation.