基于混沌时序最小二乘支持向量机的汽油机瞬态空燃比预测模型研究

摘要

For the problem that the feedback control system of transient air‐fuel ratio with oxygen sensor could not realize the real‐time demand ,the prediction model of chaos least square support vector machine was put forward .The multi‐dimensional space data were constructed with the collected test data ,the multi‐dimensional non‐linear characteristics of air‐fuel ratio time series were restored ,the reconstructed data were trained with LS‐SVM and the prediction results were acquired .The results show that the chaos LS‐SVM prediction model has the non‐linear prediction ability and can improve the prediction accuracy of air‐fuel ratio effectively compared with the Elman and BP network model .%针对由氧传感器构成的瞬态空燃比反馈控制系统无法满足实时性要求的问题，提出了基于混沌时序最小二乘支持向量机（LS‐SVM ）的瞬态空燃比预测模型。对试验采集到的一维空燃比数据利用相空间重构技术构造多维空间数据，恢复空燃比时间序列的多维非线性特性，然后采用LS‐SVM对重构后的数据进行训练及预测，得出预测结果。仿真结果表明：与Elman神经网络预测模型及前馈BP神经网络预测模型相比较，混沌时序LS‐SVM预测模型具有更强的非线性预测能力，能够有效地提高瞬态空燃比的预测精度。