Missile Payload Vibration Isolation

Isolation systems are used on spacecraft to reduce structural loadings from shock and vibration during launch. The launch environment includes both step-like acceleration and random vibration as a combined input. This requires a cumbersome high displacement isolation system when conventional passive spring and damping elements are used. Prior research using active isolation with force drivers has predicted improved performance, but high power requirements and the need for complex sensor systems presents a substantial problem for spacecraft use. This proposal describes an improved isolation system, using semi-active controls, where essentially passive spring and damping elements have their output parameters varied by the control system. This semi-active isolator is both simple and reliable, requiring a minimum of sensors for excellent performance. The design is also inherently fail safe, reverting to passive operation as a redundant operating mode. Computer simulation results are provided, comparing the semi-active isolator with comparable active and passive types. The simulation demonstrates the superiority of the semi-active device. The simulation code is PC based, and is capable of studying all known launch environments, and can be used to select isolator parameters for present and future isolation applications.