A Hybrid Actuation Approach for Vibration Control of Space Structures

Abstract

Abstract : Our research focused on vibration energy dissipation through sequential application and removal of constraints. With the goal of energy removal from membrane-like structures, we first investigated the problem of a string vibrating against a smooth obstacle. The obstacle is located at one of the boundaries and the string is assumed to wrap and unwrap the obstacle during vibration. The wrapping of the obstacle was modeled by a series of perfectly inelastic collisions and unwrapping was assumed to be energy conserving. The results indicate that the obstacle can be regarded as a passive mechanism for vibration suppression. The energy lost during each cycle of oscillation depends on the energy content of the string at the beginning of the cycle and is greater for higher modes of oscillation. Active vibration control of the string was introduced by applying a displacement constraint at the boundary instead of the obstacle. The state of vibration of the string at the time of constraint application determines if energy is added or removed from the system and this information has been used to develop a new feedback control strategy.