随着社会经济的不断发展,大空间建筑逐渐步入人们的生活中,对大空间建筑的消防技术要求逐渐提高,火焰识别技术已成为近年来研究的热点。为实现单帧图像的火焰检测,本文首先提出了一种基于RGB和HSI颜色模型的混合判据,它既保留了RGB模型...随着社会经济的不断发展,大空间建筑逐渐步入人们的生活中,对大空间建筑的消防技术要求逐渐提高,火焰识别技术已成为近年来研究的热点。为实现单帧图像的火焰检测,本文首先提出了一种基于RGB和HSI颜色模型的混合判据,它既保留了RGB模型中的直观判据,又加入了HSI模型中对于饱和度判据,效果优于两者单独使用或单纯结合的情况;同时利用基于加权欧式距离的方法对图像进行特殊灰度化处理,通过Kmeans++颜色聚类,完成火焰图像的分割,获得最终感兴趣区域;提取该区域几何轮廓并利用不规则度和形态比例等几何判据,对待检测图像进行最终的识别。为评估所提出检测方法的性能,选取典型火焰图像和非火焰图像,在Visual Studio 2013环境下进行对比实验,通过对运行时间、提取偏差率和识别误报率等结果的分析,证明了所提方法的有效性和可实现性。本文所提出的方法具有良好的检测效果,能够保证火焰提取和识别的精度,同时兼顾实时性的要求,可以应用在实际的大空间消防项目中。展开更多
根据同步施工网络控制系统的控制原理,分析了时变、随机和不确定的网络时延对同步误差控制所产生的影响。针对传统Smith预估器用于多被控对象同步控制时存在的缺陷与不足进行了分析,提出了一种改进型Smith预估器,实现了对网络时延、被...根据同步施工网络控制系统的控制原理,分析了时变、随机和不确定的网络时延对同步误差控制所产生的影响。针对传统Smith预估器用于多被控对象同步控制时存在的缺陷与不足进行了分析,提出了一种改进型Smith预估器,实现了对网络时延、被控对象纯滞后因子以及同步误差控制器的多重Smith预估补偿,将其从内部反馈回路中彻底消除,预估模型无需预估与在线测量其大小与变化规律。通过基于控制器局域网络(controller area network,简称CAN)的盾构管片拼装机同步网络控制系统,对常规比例积分微分(proportion integral derivative,简称PID)同步网络控制和基于改进型Smith预估器的PID同步网络控制性能进行了仿真对比分析,并通过实验进行了验证。结果表明,常规PID网络控制同步误差为-3～3mm,基于改进型Smith预估器的PID网络控制同步误差为-1.5～1.5mm,后者可显著提高同步施工网络控制系统的同步控制性能与精度。展开更多
Rising concern in environmental issues on global scale has made energy saving in powered equipment a very important subject.In order to improve the energy efficiency and driving range of a motor hoist,a regenerative b...Rising concern in environmental issues on global scale has made energy saving in powered equipment a very important subject.In order to improve the energy efficiency and driving range of a motor hoist,a regenerative braking system is designed and discussed.The system takes a unique ultracapacitor-only approach to energy storage system.The bi-directional bride DC？DC converter which regulates current flow to and from the ultracapacitor operates in two modes：boost and buck,depending on the direction of the flow.In order to provide constant input and output current at the ultracapacitor,this system uses a double proportional-integral（PI） control strategy in regulating the duty cycle of PWM to the DC？DC converter.The permanent magnet synchronous motor（PWSM） drive system is also studied.The space vector pulse width modulation（SVPWM） technique,along with a two-closed-loop vector control model,is adopted after detailed analysis of PMSM characteristics.The overall model and control strategy for this regenerative braking system is ultimately built and simulated under the MATLAB and Simulink environment.A test platform is built to obtain experimental results.Analysis of the results reveals that more than half of the gravitational potential energy can be recovered by this system.Simulation and experimentation results testify the validity of the double PI control strategy for interface circuit of ultracapacitor and SVPWM strategy for PMSM.展开更多
文摘随着社会经济的不断发展,大空间建筑逐渐步入人们的生活中,对大空间建筑的消防技术要求逐渐提高,火焰识别技术已成为近年来研究的热点。为实现单帧图像的火焰检测,本文首先提出了一种基于RGB和HSI颜色模型的混合判据,它既保留了RGB模型中的直观判据,又加入了HSI模型中对于饱和度判据,效果优于两者单独使用或单纯结合的情况;同时利用基于加权欧式距离的方法对图像进行特殊灰度化处理,通过Kmeans++颜色聚类,完成火焰图像的分割,获得最终感兴趣区域;提取该区域几何轮廓并利用不规则度和形态比例等几何判据,对待检测图像进行最终的识别。为评估所提出检测方法的性能,选取典型火焰图像和非火焰图像,在Visual Studio 2013环境下进行对比实验,通过对运行时间、提取偏差率和识别误报率等结果的分析,证明了所提方法的有效性和可实现性。本文所提出的方法具有良好的检测效果,能够保证火焰提取和识别的精度,同时兼顾实时性的要求,可以应用在实际的大空间消防项目中。
文摘根据同步施工网络控制系统的控制原理,分析了时变、随机和不确定的网络时延对同步误差控制所产生的影响。针对传统Smith预估器用于多被控对象同步控制时存在的缺陷与不足进行了分析,提出了一种改进型Smith预估器,实现了对网络时延、被控对象纯滞后因子以及同步误差控制器的多重Smith预估补偿,将其从内部反馈回路中彻底消除,预估模型无需预估与在线测量其大小与变化规律。通过基于控制器局域网络(controller area network,简称CAN)的盾构管片拼装机同步网络控制系统,对常规比例积分微分(proportion integral derivative,简称PID)同步网络控制和基于改进型Smith预估器的PID同步网络控制性能进行了仿真对比分析,并通过实验进行了验证。结果表明,常规PID网络控制同步误差为-3～3mm,基于改进型Smith预估器的PID网络控制同步误差为-1.5～1.5mm,后者可显著提高同步施工网络控制系统的同步控制性能与精度。
基金supported by National Key Technology Research and Development Program of China (Grant No. 2007BAF10B00)
文摘Rising concern in environmental issues on global scale has made energy saving in powered equipment a very important subject.In order to improve the energy efficiency and driving range of a motor hoist,a regenerative braking system is designed and discussed.The system takes a unique ultracapacitor-only approach to energy storage system.The bi-directional bride DC？DC converter which regulates current flow to and from the ultracapacitor operates in two modes：boost and buck,depending on the direction of the flow.In order to provide constant input and output current at the ultracapacitor,this system uses a double proportional-integral（PI） control strategy in regulating the duty cycle of PWM to the DC？DC converter.The permanent magnet synchronous motor（PWSM） drive system is also studied.The space vector pulse width modulation（SVPWM） technique,along with a two-closed-loop vector control model,is adopted after detailed analysis of PMSM characteristics.The overall model and control strategy for this regenerative braking system is ultimately built and simulated under the MATLAB and Simulink environment.A test platform is built to obtain experimental results.Analysis of the results reveals that more than half of the gravitational potential energy can be recovered by this system.Simulation and experimentation results testify the validity of the double PI control strategy for interface circuit of ultracapacitor and SVPWM strategy for PMSM.
