Enhancement of pointing performance by semi-active variable damping isolator with strategies for attenuating chattering effects

Semi-active control strategy is one of the most attractive approaches for space applications because of it provides better performance than passive systems and higher robustness than active systems. However, conventional semi-active approaches, such as skyhook and bang-bang control, cause the pointing accuracy of the on-board payload to degrade due to chattering effects created by the sudden variation of damping force when a semi-active isolation system is switched on or off. In this paper, we propose a semi-active strategy to minimize performance deterioration due to chattering effects. Numerical simulation result obtained using a simplified on-board payload model demonstrate that the proposed LQ semi-active control logic with variable damping achieves much better isolation performance than the conventional semi-active control laws under single and fly-wheel force excitation environments.