We study the pseudoholomorphic curves with brake symmetry in symplectization of a closed contact manifold.We introduce the pseudoholomorphic curves with brake symmetry and the corresponding moduli space.Then we get th...We study the pseudoholomorphic curves with brake symmetry in symplectization of a closed contact manifold.We introduce the pseudoholomorphic curves with brake symmetry and the corresponding moduli space.Then we get the virtual dimension of the moduli space.展开更多
在基于机器视觉的汽车刹车片外观检测中,刹车片图像前景分割及形状特征的提取和匹配算法是刹车片分类的关键。为实现汽车刹车片外观高精度检测分类,该文提出并实现了一种包括前景分割、几何特征提取及特征模板匹配的图像处理算法。该算...在基于机器视觉的汽车刹车片外观检测中,刹车片图像前景分割及形状特征的提取和匹配算法是刹车片分类的关键。为实现汽车刹车片外观高精度检测分类,该文提出并实现了一种包括前景分割、几何特征提取及特征模板匹配的图像处理算法。该算法首先将工业相机拍摄得到的红、绿、蓝（red green blue,RGB）格式图像转换到色调、饱和度、明度（hue saturation value,HSV）色彩空间,利用其中的饱和度S通道从暗色传送带背景中分割刹车片;然后提取刹车片区域的多维几何特征进行特征融合;最后采用基于信息熵加权的改进特征匹配算法,通过刹车片特征的信息熵对特征空间的Manhattan距离进行加权。对98张、54类刹车片图像进行了分类实验,结果表明：算法准确率为95.00%,每张平均耗时110ms,可以应用于刹车片生产过程中的实时自动分类。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
Fault diagnosis is a key issue of the CCBII(computer controlled brake II) braking system, because the CCBII braking system is very complicated and nonlinear, which may exhibit isolated and multi-component coupled faul...Fault diagnosis is a key issue of the CCBII(computer controlled brake II) braking system, because the CCBII braking system is very complicated and nonlinear, which may exhibit isolated and multi-component coupled faults. A parity space-based method was proposed for fault diagnosis of CCBII braking systems. Firstly, the mathematical models were established according to three function modules of CCBII braking systems where the air fluid theory was utilized. Then, parity vector and threshold function were designed for each output of the system so as to identify more system faults. Fault character matrix was built based on the causal relationship between the output and the fault according to the system function and internal structure. Finally, fault detection and isolation can be realized by the comparison of the observed system output and the fault character matrix. Simulation results show that the proposed method is entirely feasible and effective.展开更多
基金The first author was supported by the China Scholarship Council(CSC)(No.201806200130),the LPMC of Ministry of Education of China,and Nankai Zhide Foundation and Nankai UniversityThe second author was supported by the National Natural Science Foundation of China(Grant Nos.11971245,11771331),the LPMC of Ministry of Education of China,the Nankai Zhide Foundation and Nankai University.
文摘We study the pseudoholomorphic curves with brake symmetry in symplectization of a closed contact manifold.We introduce the pseudoholomorphic curves with brake symmetry and the corresponding moduli space.Then we get the virtual dimension of the moduli space.
文摘在基于机器视觉的汽车刹车片外观检测中,刹车片图像前景分割及形状特征的提取和匹配算法是刹车片分类的关键。为实现汽车刹车片外观高精度检测分类,该文提出并实现了一种包括前景分割、几何特征提取及特征模板匹配的图像处理算法。该算法首先将工业相机拍摄得到的红、绿、蓝（red green blue,RGB）格式图像转换到色调、饱和度、明度（hue saturation value,HSV）色彩空间,利用其中的饱和度S通道从暗色传送带背景中分割刹车片;然后提取刹车片区域的多维几何特征进行特征融合;最后采用基于信息熵加权的改进特征匹配算法,通过刹车片特征的信息熵对特征空间的Manhattan距离进行加权。对98张、54类刹车片图像进行了分类实验,结果表明：算法准确率为95.00%,每张平均耗时110ms,可以应用于刹车片生产过程中的实时自动分类。
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.
基金Projects(61071096,61073103,61003233) supported by the National Natural Science Foundation of ChinaProjects(20100162110012,20110162110042) supported by Doctoral Program of Higher Education,China
文摘Fault diagnosis is a key issue of the CCBII(computer controlled brake II) braking system, because the CCBII braking system is very complicated and nonlinear, which may exhibit isolated and multi-component coupled faults. A parity space-based method was proposed for fault diagnosis of CCBII braking systems. Firstly, the mathematical models were established according to three function modules of CCBII braking systems where the air fluid theory was utilized. Then, parity vector and threshold function were designed for each output of the system so as to identify more system faults. Fault character matrix was built based on the causal relationship between the output and the fault according to the system function and internal structure. Finally, fault detection and isolation can be realized by the comparison of the observed system output and the fault character matrix. Simulation results show that the proposed method is entirely feasible and effective.
