A general purpose rigid body dynamic analysis program with applications to control of zero angular momentum turns

Abstract

This study synthesize spatial dynamics of rigid bodies and feedback control for the control of angular momentum turns. A general-purpose computer code (named DASC) capable of performing the dynamic analysis of large scale, nonlinear, constrained multibody systems is developed and is combined with a special-purpose (feedback control) subroutine for the simulation of a cat's self-righting reflex and the pointing control of a satellite. The decentralized and hierarchical control concepts and the two-stage feedback control scheme are employed on a mechanical cat simulation. During the simulation, a multisegment, multijoint cat model can change its body orientation in midair without any external torque by moving its body segments in the appropriate manner. The above dynamic modelling and control system design can also be applied to angular momentum maneuvers of an orbiting spacecraft. The developed control scheme is simple and allows easy implementation of such multibody systems.