控制力矩陀螺框架谐波减速驱动系统建模与仿真

Modeling and Simulation of CMG Gimbal System Based on Harmonic Gear

控制力矩陀螺是航天器姿态控制系统的重要执行机构,它具有输出力矩大、速度响应快、功率消耗低、寿命长等优点,可以完成高速率的姿态机动控制.综合考虑谐波减速器的齿隙模型、非线性刚度、减速器效率等因素,对CMG框架驱动组件用谐波减速器进行精细建模.针对低速下谐波减速器的刚度较低、传动误差较大这一缺陷,建立考虑传动误差的减速器模型;与传统的不考虑传动误差的模型相比可更准确地描述谐波减速器在低速下的输出速度曲线.根据建立的CMG框架驱动系统模型,在低速下采用PID闭环控制对输出转速误差进行抑制,使输出转速误差降低了50%以上.最后分析其对谐波减速器刚度和阻尼对框架系统性能的影响.

Control moment gyro（ CMG） is one of the significant actuators of spacecraft attitude control system,which can complete the orbit maneuver in high rate,with advantages of large torque control,rapid response,low power consumption and long service life. In this paper,a dynamics model of harmonic drive used in CMG gimbal system is proposed,in which the backlash model of harmonic drive,nonlinear stiffness factor and the efficiency of the reducer are given full consideration. Transmission error is considered in the gear model. Compared with the model without transmission error,the output velocity is more accurate in describing the output curve at low speed. The model of CMG gimbal system is established,and a PID control law is designed to suppress the output transmission error,which is reduced by over50%. Finally,the effects of the stiffness and damping of harmonic gear on system performances are analyzed based on the simulation model.