圆轨道有限时间收敛导引律

Finite Time Convergence Guidance Law for Circular Orbit

运载器运送飞行器进入期望的飞行轨道,通常采用传统的闭路导引方法。导引方法仅仅能将飞行器导引到期望的目标点,也就是说到达期望的位置。但是由于速度矢量没有约束,导致到达期望的位置后速度矢量与期望的速度矢量之间有偏差,进而随着飞行器的运动,使得飞行轨道越来越偏离目标轨道。针对圆轨道入轨时的初始位置和速度误差修正和轨道精确导引问题,提出一种基于Lyapunov理论的圆轨道有限时间收敛导引律。上述导引律通过在导引律中引入轨道向径偏差和向径变化率进行反馈,来减小初始入轨位置和速度偏差并对轨道进行精确导引。通过数学仿真进行验证,结果表明圆轨道有限时间收敛导引律能有效减小初始位置和速度误差并对圆轨道进行精确导引。

The launch vehicle adopts the iterative guidance method.This method only sends the load to expected position.Because of without velocity constraint,actual velocity is different from expected velocity.Furthermore,the deviation becomes bigger over time.A finite time convergence method based the Lyapunov stability theory for reducing circular orbit original error and high precision guidance is proposed in this paper.The guidance can reducethe initial orbital position and velocity deviation and guides the orbit accurately by introducing the radial deviation and the rate of change of the orbit into the guidance for feedback.The simulation results show that the finite-time convergence guidance of circular orbit can effectively reduce the initial position and velocity errors and guide the circular orbit accurately.With the use of geocentric radial error and geocentric radial rate,this method corrects original geocentric radial error and guides accurately.Numerical simulations have demonstrated the effectiveness of the approach proposed.