建模变量对非定常空气动力数学模型的影响

摘要

The fuzzy logic modeling of rolling moment is established with different modeling variables, based on the wind tunnel test results of large-amplitude yawing motion and rolling motion. The effects of different variables on the model precision are analyzed. Using reasonable variables obtained from above, the unsteady aerodynamic model of yawing-rolling coupled-motion is set up by means of the fuzzy logic, and the aerodynamic coefficients are acquired.Comparing calculation results with test results, the influence of model accuracy by variables of different combination is investigated. In spite of any motion forms, the relationship between variables is the main factor that influences the model precision. Considering single freedom motion, α, β, ωy (ωx) should be selected as modeling variables; likewise, α, β, ωx, ωy regarded as modeling variables are better than others for coupled-motion.%在某飞机大振幅偏航、滚转单自由度运动风洞试验的基础上,采用不同建模变量,用模糊逻辑方法建立滚转力矩模型,分析研究了不同变量对模型精度的影响;然后运用得到的较为合理的建模变量,采用非定常模型获取偏航-滚转耦合运动的气动力系数,并与试验结果比较,分析不同的变量组合对该模型预测精度的影响.结果表明,不论在哪种运动形式下,建模变量间的相关性都是造成模型预测精度低的主要因素.对于单自由度运动,应取α、β、ωy(ωx)为建模变量;对于耦合运动,以α、β、ωx、ωy为建模变量较好.