飞轮转速过零时卫星姿态的非线性控制

Nonlinear Control Law of Satellites Attitude at Zero-Speed of Reaction Wheels

当飞轮转速过零时，摩擦力矩发生非线性变化，控制作 用力矩出现不确定性，从而影响卫星的姿态控制性能。文章基于一种具有鲁棒性的非线性控 制方法，发展了简单、可靠和稳定的非线性反馈控制律。仿真实例表明，该方法能够有效地 抑制反作用飞轮转速过零时引起的姿态扰动，从而实现高精度的卫星姿态控制。

When reaction wheels rotate at nearly zero speed,the mom ent of friction will vary discontinuously.This leads to the uncertainty of contr ol moment,which influences the performances of satellite attitude control. Based on a nonlinear control approach,a nonlinear control law is developed to im prove attitude control performances.The analyses show the control law is convinc ing for zero-speed wheel.Finally,a simulation example is provided.Compared with traditional linear control law,the nonlinear control law is fully effective in d ealing with the uncertainties of wheels' control output. Moreover,the nonlinear control law is also quite simple.It occupies few memory c apacity compared with the linear control law and consumes a little CPU time.As a result,it is possible that the nonlinear control law is used directly on board. Subject Term Attitude control Reaction wheel Nonlinear control S atellite