皮卫星偏置动量轮在轨备份切换策略

参考微动量轮的实测数据,讨论并建立描述转速随机变化的马尔可夫模型.在该模型基础上,提出并分析用于皮卫星的偏置动量轮备份、切换策略.该策略定义了4个正常模式和3个异常模式：在普通情况下,系统在正常模式下定时切换飞轮；当故障发生时,系统切入异常模式,隔离故障飞轮.与常规的冷备份方法相比,该策略为飞轮性能、功能的故障检测提供了更方便的途径,同时在更长时间段内,能够保持星体连续姿态稳定.数学仿真表明,应用本文策略,正常情况切换时,造成的姿态扰动最大不超过20°；对于突发故障,切换带来的姿态扰动恢复时间约为30 min.

In-orbit backup and switch method for pico-satellite’s bias momentum wheel

A Markov model describing rotation speed variation was discussed and established according to a micro momentum wheel test. Then a backup and switch method for pico-satellite’s bias momentum wheel was introduced and analyzed. The method includes four normal modes and three exceptional modes. Generally, system operates in normal modes, periodically switching between two flywheels. When failure arises, system switches to exceptional modes, making the broken wheel isolated. The method provides a more convenient way for both flywheel function and performance failure detection compared with traditional cold backup method; and can keep stabilizing satellite attitude continuously for much longer time. Simulation results show that the application of the method can keep attitude error within 20° in normal switch case; and the attitude disorder due to emergency switch can be restored in about 30 min for accidental flywheel failure.