基于改进局部线性模型树的航空发动机过渡态非线性辨识  

Nonlinear Identification for Aero-engine Transient Process Based on Modified Local Linear Model Tree

作　　者：王伟 李建锋 刘帅 WANG Wei;LI Jianfeng;LIU Shuai(Airworthiness College,Civil Aviation University of China,Tianjin 300300,China;Sino-European Institute of Aviation Engineering,Civil Aviation University of China,Tianjin 300300,China)

机构地区：[1]中国民航大学适航学院,天津300300 [2]中国民航大学中欧航空工程师学院,天津300300

出　　处：《信息与控制》2020年第5期560-569,577,共11页Information and Control

摘　　要：为了解决在采用局部线性模型树(LOcal Linear MOdel Tree,LOLIMOT)辨识发动机非线性系统时,出现的辨识网络复杂和模型精度问题,提出一种将非线性自回归滑动平均模型(NARMAX)和LOLIMOT网络融合的改进神经网络结构.基于非线性自回归滑动平均模型NARMAX的思想,将原始局部子模型的线性函数替换为非线性多项式函数,并基于AIC(Akaike information criterion)显著性准则的前向选择法对非线性项按照重要性程度进行选择,将简化后的非线性函数用于构建原始LOLIMOT模型局部子模型,形成一种改进LOLIMOT网络模型.通过某航空发动机过渡态下的辨识实验表明,改进算法能够将原LOLIMOT模型复杂度降低46%左右,相对预测精度提高50%以上,验证了在对发动机模型复杂度和精度要求较高的领域,改进模型是一种更加有效的网络结构.To solve the problems associated with complex network structures and low model accuracy when using the local linear model tree( LOLIMOT) to identify nonlinear engine systems,we propose a modified LOLIMOT structure that combines a nonlinear autoregressive moving average model( NARMAX) with a LOLIMOT network. Based on the concepts underlying NARMAX,we replace the linear function of the local sub-model with a nonlinear polynomial function. Using a forward selection method based on the AIC saliency criterion,we then select the appropriate nonlinear terms according to their importance,and use the simplified nonlinear function to construct the local sub-model of LOLIMOT,which yields a modified LOLIMOT. We then use the modified LOLIMOT to identify a nonlinear transient process for an aero-engine. The results show that the modified LOLIMOT reduces the complexity of the original model by 46% and increases the prediction accuracy by at least 50%. These results verify that the modified model has a more efficient network structure in the aeroengine control field,low model complexity,and the ability to meet the demand for high accuracy.

关 键 词：航空发动机 非线性系统 局部线性模型树(LOLIMOT) 系统辨识 AIC准则 

分 类 号：V235.14[航空宇航科学与技术—航空宇航推进理论与工程]