全电推进卫星小推力变轨策略星上计算方法研究

Low-Thrust Orbit Transfer Strategy On-Board Compution for All Electric Propulsion Satellite

关键词:  全电推进卫星  小推力变轨  星上计算  Lyapunov反馈制导律  推力矢量分段固定法

Key words:  All electric propulsion satellite  Low thrust orbit transfer  On-board computing  Lyapunov feedback guidance law  Thrust vector piecewise fixing method

摘要:

全电推进卫星星上自主变轨，是全电推进卫星重要的发展方向。为了获得运算量小、计算简单、可以星上计算且变轨时间最短的小推力变轨策略，研究了Lyapunov反馈制导律和推力矢量分段固定法两种方法。基于Lyapunov反馈制导律的变轨策略，权重系数在地面进行优化，推力指向星上实时计算，在标称任务工况下变轨时间比理论最优解加长8.18%。推力矢量分段固定法变轨策略更为简单，每10天星上对两个关键控制参数Ψ₁，Ψ₂进行修正，推力指向变化规律恒定，变轨时间比理论最优解加长7.43%。两种方法都具有任务适应性好和计算简单的优点，Lyapunov反馈制导律对姿态控制能力要求较高，推力矢量分段固定法姿态控制要求容易满足，后者更适合于卫星应用。

Abstract:

The autonomous orbit transfer for all-electric propulsion satellite is an important development direction. In order to obtain a low-thrust orbital maneuver on board strategy with less computational complexity, simpler computation, shortest orbital maneuver duration, two methods, Lyapunov feedback guidance law and thrust vector piecewise fixing, are studied. Based on Lyapunov feedback guidance law, the control gain parameters are optimized on the ground, and the thrust direction is calculated on board in real time. Under nominal mission conditions, the orbit transfer duration is 8.18% longer than the theoretical optimal solution. The strategy of thrust vector piecewise fixed method is simpler. The two key control parameters Ψ₁ and Ψ₂ are modified every 10 days on board. The thrust direction change law is constant, and the orbit transfer duration is 7.43% longer than the theoretical optimal solution. Both methods have the advantages of good mission adaptability and simple calculation. The Lyapunov feedback guidance law requires high attitude control capability, and the thrust vector piecewise fixed method is easy to achieve attitude control. The latter is more suitable for engineering applications.