双框架磁悬浮控制力矩陀螺(Double gimbal magnetically suspended control moment gyroscope,DGMSCMG)是由磁悬浮高速转子系统与内框架、外框架速率伺服系统构成的航天器新型姿控执行机构。由于非线性及三个子系统间的强耦合,框架转动时磁悬浮转子位移急剧增大影响稳定性,同时框架系统的响应速度显著下降,称之为动框架效应。该效应严重影响了DGMSCMG的功能,必须加以抑制。建立DGMSCMG的动力学模型,分析三个子系统间的动力学耦合机理,提出一种基于复合控制的补偿方法,引入针对陀螺项的反馈和针对框架角速率给定的前馈消除磁悬浮转子附加位移,提高框架系统响应速度,并对补偿后系统做全局稳定性分析。仿真和试验结果表明,该方法能在保证系统稳定性的前提下有效抑制动框架效应,满足DGMSCMG的功能要求。
Double gimbal magnetically suspended control moment gyroscope (DGMSCMG) is made up of magnetically suspended high-speed rotor system, inner and outer gimbal rate-servo system, and serves as novel attitude control actuator of spacecraft. Owing to nonlinearity and strong couple of three subsystems, rotor axis run-out will grow significantly to reduce system stability severely and response speed goes lower when gimbal revolving, which is called moving-gimbal effects. The effects influence DGMSCMG function severely and must be depressed. Based on DGMSCMG dynamic model set up in this paper and couple mechanism analysis, a novel compensation method based on compound control is presented, which introduces feedback of gyro item and feedforward of preset gimbal rate to depress additional displacement of rotor and raise response speed of gimbal, and system global stability is analyzed. Results of simulation and experiment show that the proposed method can depress moving-gimbal effects effectively to satisfy DGMSCMG requirement besides remaining stability.