Inertial actuator design for maximum passive and active energy dissipation in flexible space structures

Abstract

The selection of the passive parameters for passive and active inertial vibration absorbers intended for use in large flexible space structures is investigated. Optimal passive vibration absorbers are designed for one and two WF structural representations using three parameter optimization techniques: minimum maximum steady-state response; pole placement; and quadratic cost minimization. The three techniques yield nearly identical results. Theoretically, a single mode damping ratio of 5% of critical damping can be achieved with a passive vibration absorber mas that is equal to 2% of the structural modal mass. Control actuators, which incorporate passive absorber components are also designed. Optimal gains for specific passive component values are determined using Linear Quadratic Regulator formulations. The optimal actuator is the one that's combined passive components and active gains minisizes the quadratic cost. The optimal actuator's passive design is near that of the optimal passive vibration absorber leading to a near optimal sequential design technique. Proof of concept laboratory tests were performed on a quasi free-free beaa. Electromagnetic, inertial-reaction devices usable in both active and passive configurations were implemented. Experimentally, a single mode damping of