Light impulsive damping of spacecraft exhibiting normal mode behavior

Abstract

This paper develops an impulsive damping control algorithm suitable for spacecraft. The fuel optimal solutions to the problem of damping the motion of spacecraft consists of impulsive control forces applied at repeated instances in time. The instances in time occur when the spacecraft undergoes maximum absolute velocities and minimum absolute displacements. This paper approximates impulses by short duration pulses. Maximum absolute velocities and minimum absolute displacements are then approximated by transient values of their respective standard deviations. Impulsive damping is achieved by applying either a large single pulse or smaller repeated pulses. A near fuel optimal mode preserving impulsive damping control algorithm is developed next. The algorithm exhibits the following properties: 1) the impulsive damping control algorithm is independent of spacecraft stiffness, 2) the associated control forces are proportional to spacecraft inertia, and 3) the impulsive damping control algorithm is decentralized. The impulsive damping of a cantilever beam demonstrates the results.

Fuel-optimal propulsive reboost of flexible spacecraft

“…These investigations led to a feedback algorithm in which fuel-optimal pulses of reaction control jets act on the system at instances of peak local velocities. 15 ' 18 This approach has been shown to be effective but once again is not based on an exact minimization. Indeed, the previously cited near fuel-optimal control solutions were developed because exact solutions were unavailable.…”