基于LSTM−Transformer的上隅角氧气浓度预测与控制

Prediction and control of oxygen concentration in upper corner based on LSTM-Transformer

  • 摘要: 针对现有均压通风系统因依赖人工调节或单一阈值控制而存在显著传感滞后与响应超调的问题,提出一种基于长短时记忆(LSTM)−Transformer的上隅角氧气浓度预测与控制方法。构建了融合LSTM与Transformer全局注意力机制的混合模型,利用多源监测数据实现对上隅角氧气浓度的精准超前预测;设计了前馈−反馈复合控制策略,将LSTM−Transformer的预测输出作为前馈信号,以前馈信号补偿时间滞后,并在控制策略中引入动态权重调节机制,同时采用遇限削弱积分法对PID算法进行改进,以消除稳态误差,提升系统的动态响应安全性和稳定性;通过计算流体力学数值模拟解析百叶风窗的非线性阻力特性,建立“开度−阻力”映射模型,将PID控制器输出的目标阻力实时反解为精确叶片角度,从而补偿风窗自身的非线性响应特性,提高执行精度。实验结果表明,与随机森林、BP神经网络、支持向量机、卷积神经网络及单一LSTM等主流时序预测模型相比,LSTM−Transformer在均方根误差、平均绝对误差、拟合优度、平均偏差误差等指标上表现最优。现场测试结果表明:LSTM−Transformer与PID复合控制策略可使系统整体响应时间缩短1~2 min,将上隅角氧气浓度波动范围稳定在18%~19.5%以内,有效抑制了超调现象,实现了通风调控从“被动响应”向“主动干预”的转变。

     

    Abstract: To address the significant sensing lag and response overshoot in existing pressure-equalized ventilation systems caused by manual adjustment or single-threshold control, a method for predicting and controlling oxygen concentration in the upper corner based on Long Short-Term Memory (LSTM)-Transformer was proposed. A hybrid model integrating LSTM and the global attention mechanism of Transformer was constructed to achieve accurate advance prediction of oxygen concentration in the upper corner using multi-source monitoring data. A feedforward-feedback composite control strategy was designed, in which the prediction output of LSTM-Transformer was used as the feedforward signal to compensate for time lag; a dynamic weight adjustment mechanism was introduced into the control strategy, and the limited-weakening integral method was used to improve the PID algorithm, eliminating steady-state error and improving dynamic response safety and stability. Numerical simulation based on computational fluid dynamics was used to analyze the nonlinear resistance characteristics of the louvered air window, and an opening-resistance mapping model was established. The target resistance output by the PID controller was inversely solved in real time into an accurate blade angle, thereby compensating for the nonlinear response characteristics of the air window and improving execution accuracy. Experimental results showed that compared with mainstream time-series prediction models such as random forest, BP neural network, support vector machine, convolutional neural network, and single LSTM, LSTM-Transformer performed best in root mean square error, mean absolute error, coefficient of determination, and mean bias error. Field test results showed that the LSTM-Transformer and PID composite control strategy shortened the overall system response time by 1-2 min, stabilized the fluctuation range of oxygen concentration in the upper corner in 18%-19.5%, effectively suppressed overshoot, and realized the transition of ventilation regulation from passive response to active intervention.

     

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