改进变步长算法在实时飞行仿真中的应用

飞行模拟机是民航训练飞行员的重要装备,飞行仿真系统是飞行模拟机的重要系统之一.飞行仿真要建立飞机的全量运动方程,利用数值算法解算运动方程达到仿真飞机飞行状况的目的.采用四元数法表示的飞机欧拉方程能够克服普通欧拉方程奇异性,但用定步长方法解算会产生较大累积误差,所以必须采用变步长方法.实时飞行仿真要求较高的实时性与逼真度,通过仿真试验分析,确定了采用一种改进变步长2阶Runge-Kutta法,该方法具有迭代次数少,解算精度高,实时性强的优点.利用该改进变步长算法,编写了实时飞行系统仿真软件,软件中使用相应算法解决了变步长算法选择步长与系统迭代定时时间不匹配的矛盾,实现了精确的实时仿真.

Application of Modified Variable Step Algorithm in Real -time Flight Simulation

Flight Simulator is an important device for pilot training of civil aviation.Flight simulation system is one of the important systems of flight simulator.Full motion equations must be built in flight simulation.Numerical method should be used to solve motion equations so that aircraft flight status can be simulated.Aircraft Euler equation of quaternion algorithm can overcome the singularity of common Euler equation.But using single step algorithm to solve the equation will cause great cumulated error,so variable step algorithm must be adopted.High real-time quality and fidelity are requested in real-time flight simulation.Through simulation experiment and analysis,it is made certain that a algorithm of modified variable step 2 rank Runge-Kutta can be used,which has advantages of low iterative times,high solving precision and high real-time quality.Real-time flight system simulation software is developed using the modified variable step method.In the software,corresponding algorithm is adopted,which solves the conflict of mismatch between step chosen by variable step algorithm and iterative timing time,and precision real-time simulation is realized.