After a recursive multi-step-ahead predictor for nonlinear systems based on local recurrent neural networks is introduced, an intelligent FID controller is adopted to correct the errors including identified model erro...After a recursive multi-step-ahead predictor for nonlinear systems based on local recurrent neural networks is introduced, an intelligent FID controller is adopted to correct the errors including identified model errors and accumulated errors produced in the recursive process. Characterized by predictive control, this method can achieve a good control accuracy and has good robustness. A simulation study shows that this control algorithm is very effective.展开更多
Nonlinear model predictive controllers(NMPC)can predict the future behavior of the under-controlled system using a nonlinear predictive model.Here,an array of hyper chaotic diagonal recurrent neural network(HCDRNN)was...Nonlinear model predictive controllers(NMPC)can predict the future behavior of the under-controlled system using a nonlinear predictive model.Here,an array of hyper chaotic diagonal recurrent neural network(HCDRNN)was proposed for modeling and predicting the behavior of the under-controller nonlinear system in a moving forward window.In order to improve the convergence of the parameters of the HCDRNN to improve system’s modeling,the extent of chaos is adjusted using a logistic map in the hidden layer.A novel NMPC based on the HCDRNN array(HCDRNN-NMPC)was proposed that the control signal with the help of an improved gradient descent method was obtained.The controller was used to control a continuous stirred tank reactor(CSTR)with hard-nonlinearities and input constraints,in the presence of uncertainties including external disturbance.The results of the simulations show the superior performance of the proposed method in trajectory tracking and disturbance rejection.Parameter convergence and neglectable prediction error of the neural network(NN),guaranteed stability and high tracking performance are the most significant advantages of the proposed scheme.展开更多
In recent years, advanced control technologies have been used for the optimum control of a cold storage. But there are still a lot of shortcomings. One of the main problems is that the traditional methods can't re...In recent years, advanced control technologies have been used for the optimum control of a cold storage. But there are still a lot of shortcomings. One of the main problems is that the traditional methods can't realize the on-line predictive optimum control of a refrigerating system with simple and valid algorithms. An RBF neural network has a strong ability in nonlinear mapping, a good interpolating value performance, and a higher training speed. Thus a two-stage RBF neural network is proposed in this paper. Combining the measured values with the predicted values, the two-stage RBF neural network is used for the on-line predictive optimum control of the cold storage temperature. The application results of the new methods show a great success.展开更多
热电联产(combined heat and power,CHP)机组作为区域综合能源系统中的核心耦合单元,是实现其高效运行的关键。然而CHP机组固有的热电耦合特性对其灵活调节能力和运行性能的提升存在一定限制,且其“以电定热”和“以热定电”的调度策略...热电联产(combined heat and power,CHP)机组作为区域综合能源系统中的核心耦合单元,是实现其高效运行的关键。然而CHP机组固有的热电耦合特性对其灵活调节能力和运行性能的提升存在一定限制,且其“以电定热”和“以热定电”的调度策略缺乏前瞻性考虑多元负荷和可再生能源的波动特征。集成储能系统可有效实现热电解耦,然而储能的充放电能力受其能量状态的影响。基于此,该文采用长短记忆神经网络对区域综合能源系统中多元负荷及可再生能源进行预测,以考虑多元负荷及可再生能源的时序波动,提出耦合源-荷多元预测与电热混合储能的主动调度策略。构建计及碳排放惩罚、可再生能源弃电惩罚及运行成本的优化调度模型。以某区域综合能源系统为例,对比分析“以电定热”、“以热定电”和“主动调度”策略。结果显示,长短记忆神经网络的最大预测误差为4.7%。采用电-热混合储能主动调度策略的运行成本比“以电定热”和“以热定电”运行策略分别降低了11.12%和3.67%。此外,主动调度策略可在平滑热电比负荷曲线的同时降低区域综合能源系统购电成本,并且对CHP机组的能效具有促进作用,进一步降低了区域综合能源系统的运行成本。展开更多
风速和风向是影响高速列车运行安全的重要因素,对高铁沿线的大风风速和风向进行有效预测有助于及时地对列车运行状况进行评估和预警。目前高铁大风领域的研究主要集中在风速的预测,尚未考虑风速风向的联合预测。基于深度循环神经网络—...风速和风向是影响高速列车运行安全的重要因素,对高铁沿线的大风风速和风向进行有效预测有助于及时地对列车运行状况进行评估和预警。目前高铁大风领域的研究主要集中在风速的预测,尚未考虑风速风向的联合预测。基于深度循环神经网络—长短记忆(LSTM)模型,提出独立预测法、分量预测法和多变量预测法等3种风速与风向联合预测方法,并利用兰新高铁大风监测实测数据对沿线多个基站的短期风速和风向进行同步联合预测。首先,通过归一化预处理原始风向和风速序列,并运用控制变量法确定最优时间步长和模型参数。其次,采用BPTT(Backpropagation Through Time)和Adam算法进行迭代训练,并结合早停法控制收敛,得到优化后的网络结构。最后,利用训练好的LSTM网络,采用3种方法对风速和风向进行联合预测。4个基站的实验结果表明,优化后的LSTM模型可以有效提取风速风向时间序列的长期依赖特征,结合联合预测方法能够实现对风速和风向的高精度同步预测;3种联合预测方法都能在较小范围内准确预测风速和风向,除5520基站外,风速预测误差在15%以内,风向预测误差在20%以内,其中多变量预测法表现出最优的整体预测精度,独立预测法次之。本研究为风速风向的联合预测提供了新的视角,对保障高铁列车运行的安全性具有参考价值。展开更多
基金This project was supported by the National Natural Science Foundation of China(60174021)Natural Science Foundation Key Project of Tianjin(013800711).
文摘After a recursive multi-step-ahead predictor for nonlinear systems based on local recurrent neural networks is introduced, an intelligent FID controller is adopted to correct the errors including identified model errors and accumulated errors produced in the recursive process. Characterized by predictive control, this method can achieve a good control accuracy and has good robustness. A simulation study shows that this control algorithm is very effective.
文摘Nonlinear model predictive controllers(NMPC)can predict the future behavior of the under-controlled system using a nonlinear predictive model.Here,an array of hyper chaotic diagonal recurrent neural network(HCDRNN)was proposed for modeling and predicting the behavior of the under-controller nonlinear system in a moving forward window.In order to improve the convergence of the parameters of the HCDRNN to improve system’s modeling,the extent of chaos is adjusted using a logistic map in the hidden layer.A novel NMPC based on the HCDRNN array(HCDRNN-NMPC)was proposed that the control signal with the help of an improved gradient descent method was obtained.The controller was used to control a continuous stirred tank reactor(CSTR)with hard-nonlinearities and input constraints,in the presence of uncertainties including external disturbance.The results of the simulations show the superior performance of the proposed method in trajectory tracking and disturbance rejection.Parameter convergence and neglectable prediction error of the neural network(NN),guaranteed stability and high tracking performance are the most significant advantages of the proposed scheme.
文摘In recent years, advanced control technologies have been used for the optimum control of a cold storage. But there are still a lot of shortcomings. One of the main problems is that the traditional methods can't realize the on-line predictive optimum control of a refrigerating system with simple and valid algorithms. An RBF neural network has a strong ability in nonlinear mapping, a good interpolating value performance, and a higher training speed. Thus a two-stage RBF neural network is proposed in this paper. Combining the measured values with the predicted values, the two-stage RBF neural network is used for the on-line predictive optimum control of the cold storage temperature. The application results of the new methods show a great success.
文摘热电联产(combined heat and power,CHP)机组作为区域综合能源系统中的核心耦合单元,是实现其高效运行的关键。然而CHP机组固有的热电耦合特性对其灵活调节能力和运行性能的提升存在一定限制,且其“以电定热”和“以热定电”的调度策略缺乏前瞻性考虑多元负荷和可再生能源的波动特征。集成储能系统可有效实现热电解耦,然而储能的充放电能力受其能量状态的影响。基于此,该文采用长短记忆神经网络对区域综合能源系统中多元负荷及可再生能源进行预测,以考虑多元负荷及可再生能源的时序波动,提出耦合源-荷多元预测与电热混合储能的主动调度策略。构建计及碳排放惩罚、可再生能源弃电惩罚及运行成本的优化调度模型。以某区域综合能源系统为例,对比分析“以电定热”、“以热定电”和“主动调度”策略。结果显示,长短记忆神经网络的最大预测误差为4.7%。采用电-热混合储能主动调度策略的运行成本比“以电定热”和“以热定电”运行策略分别降低了11.12%和3.67%。此外,主动调度策略可在平滑热电比负荷曲线的同时降低区域综合能源系统购电成本,并且对CHP机组的能效具有促进作用,进一步降低了区域综合能源系统的运行成本。
文摘风速和风向是影响高速列车运行安全的重要因素,对高铁沿线的大风风速和风向进行有效预测有助于及时地对列车运行状况进行评估和预警。目前高铁大风领域的研究主要集中在风速的预测,尚未考虑风速风向的联合预测。基于深度循环神经网络—长短记忆(LSTM)模型,提出独立预测法、分量预测法和多变量预测法等3种风速与风向联合预测方法,并利用兰新高铁大风监测实测数据对沿线多个基站的短期风速和风向进行同步联合预测。首先,通过归一化预处理原始风向和风速序列,并运用控制变量法确定最优时间步长和模型参数。其次,采用BPTT(Backpropagation Through Time)和Adam算法进行迭代训练,并结合早停法控制收敛,得到优化后的网络结构。最后,利用训练好的LSTM网络,采用3种方法对风速和风向进行联合预测。4个基站的实验结果表明,优化后的LSTM模型可以有效提取风速风向时间序列的长期依赖特征,结合联合预测方法能够实现对风速和风向的高精度同步预测;3种联合预测方法都能在较小范围内准确预测风速和风向,除5520基站外,风速预测误差在15%以内,风向预测误差在20%以内,其中多变量预测法表现出最优的整体预测精度,独立预测法次之。本研究为风速风向的联合预测提供了新的视角,对保障高铁列车运行的安全性具有参考价值。
