Control of chaotic motion in a spinning spacecraft with a circumferential nutational damper

Control of chaotic vibrations in a simplified model of a spinning spacecraf t with a circumferential nutational damper is achieved using two techniques . The control methods an implemented on a realistic spacecraft parameter co nfiguration which has been found to exhibit chaotic instability when a sinu soidally varying torque is applied to the spacecraft for a range of forcing amplitude and frequency. Such a torque, in practice, may arise in the plat form of a dual-spin spacecraft under malfunction of the control system or f rom an unbalanced rotor or from vibrations in appendages. Chaotic instabili ties arising from these torques could introduce uncertainties and irregular ities into a spacecraft's attitude and consequently could have disastrous a ffects on its operation. The two control methods, recursive proportional fe edback (RPF) and continuous delayed feedback, are recently developed techni ques for control of chaotic motion in dynamical systems. Each technique is outlined and the effectiveness of the two strategies in controlling chaotic motion exhibited by the present system is compared and contrasted. Numeric al simulations are performed and the results are studied by means of time h istory, phase space, Poincare map, Lyapunov characteristic exponents and bi furcation diagrams.