基于VW-IGRBF神经网络的出水BOD软测量

Soft-Sensing of Effluent BOD Based on VW-IGRBF Neural Network

针对污水处理过程具有复杂非线性特性以及出水BOD难以精确测量的问题,文中提出一种基于变宽度的逆平方根和高斯函数线性组合的RBF神经网络软测量方法。神经网络的激活函数由逆平方根函数和高斯函数线性组合,弥补了单一激活函数在某些区间饱和的问题,提高了隐层激活函数的表达能力和自适应能力。由于激活函数的宽度对模型的泛化性能有较大的影响,因此引入基于核密度的变宽度策略可以有效提高网络泛化能力。文中采用改进LM算法实现了神经网络参数的在线学习。基于污水处理过程实际运行数据的仿真实验表明,所提方法对于出水BOD具有较高的预测精度和良好的自适应能力。

In view of the problem that the wastewater treatment process has complex nonlinear characteristics and the effluent BOD is difficult to accurately measure,a soft measurement method based on VW-IGRBF neural network is proposed in this study.The activation function of the neural network is a linear combination of the inverse square root function and the Gaussian function,which makes up for the saturation of a single activation function in certain intervals,and improves the expression and self-adaptability of the hidden activation function.Since the width of the activation function has a greater impact on the generalization performance of the model,a variable width strategy based on kernel density is introduced to improve the generalization ability of the network.In this study,the improved LM algorithm is used to realize the online learning of neural network parameters.Simulation experiments based on actual operating data of the wastewater treatment process show that the proposed VW-IGRBF method has higher prediction accuracy and better adaptive ability for effluent BOD.