基于改进BP神经网络的风洞天平静态校准研究

Research on static calibration of wind tunnel balances based on improved BP neural network

  • 摘要: 针对风洞天平静态校准传统校准模型非线性误差较大的问题,采用BP神经网络建立了天平校准模型。三分量天平的BP神经网络模型为典型三层神经网络(“3–7–3”结构);BP神经网络模型校准精准度满足天平静态校准合格指标,轴向力和俯仰力矩分量校准性能优于传统模型,法向力分量校准性能则略低于传统模型。针对BP神经网络存在的不足,采用经混合策略改进的蝴蝶算法优化BP神经网络的初始权值和阈值,优化后的BP神经网络收敛精度和收敛速度得到提高。使用三分量应变天平校准数据进行了仿真实验,以天平输出信号值和天平加载载荷值作为输入和输出构建BP神经网络。传统校准模型、BP神经网络校准模型、蝴蝶算法优化BP神经网络校准模型的仿真实验结果对比表明:使用优化BP神经网络模型拟合天平校准公式,其校准性能比传统校准模型提高70%~90%,可有效消除传统校准模型非线性误差,显著提高天平静态校准精准度。

     

    Abstract: Addressing the issue of relatively large nonlinear errors in traditional calibration models for static calibration of the wind tunnel balance, researchers established a balance calibration model using the BP neural network. The BP neural network model for the three-component balance is a typical three-layer neural network, specifically manifested as a “3–7–3” structure. The precision of the BP neural network model meets the qualified criteria for static balance calibration. Its calibration performance in axial force and pitching moment components surpasses that of the traditional model, although it is slightly inferior in the normal force component. To compensate for the deficiencies of the BP neural network, an improved Butterfly Optimization Algorithm with a hybrid strategy is introduced to optimize the initial weights and thresholds. The optimized BP neural network exhibits enhanced convergence accuracy and speed. The present study utilizes the calibration data of the three-component strain gauge balance from simulation experiments, with the balance output signal values and loading load values as inputs and outputs for constructing the BP neural network. A comparison is made among between the simulation results of the traditional calibration model, the BP neural network calibration model, and the Butterfly Optimized Algorithm-BP neural network calibration model. The results indicate that the optimized BP neural network model fitting the balance calibration formula improved calibration performance by 70% – 90% compared to the traditional calibration model. It effectively eliminates the nonlinear errors of the traditional calibration model and significantly improves the precision of static balance calibration.

     

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