摘要:
In hydraulic system of injection machine, electro-hydraulic proportional flow valve is used to change complex variable pump output flow and power in order to adapt to load change and energy saving.In this paper ,it introduces the working principle of electro-hydraulic proportional flow valve and how control the complex variable pump. Mathematical modeling of proportional flow valve is built and simulations based on Matlabsimulink software is done. It analyses dynamic characteristics of complex variable pump in different electricity. The results are helpful in improving the pump efficiency and response,and they provide theoretical basis for energy saving.
摘要:
Intensity inhomogeneity may cause considerable difficulties in segmentation of CT image. In order to overcome the difficulties caused by intensity inhomogeneity, the region-scalable fitting (RSF) model was put forward. RSF model draws upon intensity information in local regions with a controllable scale. But only using intensity information may lead to slow convergence rate and poor denoise ability. Combining the method of robust statistics, RSF model is improved in this paper. In the improved model, the intensity in RSF model is replaced with local robust statistics which is the weighted combination of inter-quartile range, mean absolute deviation and intensity median in local region. Inter-quartile range and mean absolute deviation in local region are introduced to sharpen object boundaries, and intensity median in local region is introduced to reduce image noise. The contrast experiments between RSF model and the improved model are provided, which demonstrate the fast convergence rate and robustness to noise of the improved model.
摘要:
The hysteresis nonlinearity reduces the accuracy of precision instrument.In order to mitigate the effect of the hysteresis, it is necessary to build hysteresis model and compensate hysteresis nonlinearity.The Krasnosel'skii- Pokrovkii (KP) operator is used to build hysteresis model, which the model is divided into linear part and nonlinear part. The KP compensating operator is proposed to compensate nonlinear part of hysteresis model. The Sliding model adaptive control law for the control method is deduced from the Lyapunov stability theorem. The emulational results confirmed the availability of hysteresis nonlinear compensation control.
摘要:
This paper analysises and evaluates vibration situation and gives the general procedure for vibration analysis of pumps units, which contain determination of each evaluation matter-element and comprehensive evaluation method based on matter-element. Evaluation matter-element is established by evaluation system of pumps vibration, aimed at a particular example. The factors affecting the vibration of the pump unit has three major factors of the mechanical, hydraulic, electrical, sub-factors of the three factors. According to the characteristics of the pump unit vibration and the current technical condition, the vibration is divided into five levels: most serious, more serious, normal, minor, and slight. The evaluation weight matter-element are established by using AHP, weight are determined by using the combination of AHP and entropy, finally comprehensive evaluation of pumps vibration performance is practiced. Thus, this evaluation is feasible and useful.
作者机构:
[Zhou, Ju] Univ South China, Sch Mech Engn, Hengyang, Peoples R China.;[Su, Jin Ying] HengYang Junjie Machinery Co Ltd, Hengyang, Peoples R China.
通讯机构:
[Zhou, Ju] U;Univ South China, Sch Mech Engn, Hengyang, Peoples R China.
会议名称:
the 2012 International Conference on Manufacturing Engineering and Automation (2012年制造工程与自动化国际会议(ICMEA2012))
会议时间:
2012-11-16
会议地点:
广州
会议主办单位:
[Zhou, Ju] Univ South China, Sch Mech Engn, Hengyang, Peoples R China.^[Su, Jin Ying] HengYang Junjie Machinery Co Ltd, Hengyang, Peoples R China.
会议论文集名称:
the 2012 International Conference on Manufacturing Engineering and Automation (2012年制造工程与自动化国际会议(ICMEA2012))论文集
关键词:
coupled heat and moisture transfer;transient moisture content;multi-layer porous building envelope
摘要:
A new facility was presented which can expediently and cheaply measure the transient moisture content profile in multi-layer porous building envelope. Then, a common multi-layer porous building envelope was provided, which was constructed by cement mortar-red brick-cement plaster. With this kind of building envelope installed in the south wall, a well-controlled air-conditioning room was set up in Changsha, which is one of typical zones of hot and humid climate in China. And experiments were carried out to investigate the temperature and moisture distribution in multi-layer building envelope in summer, both in sunny day and rainy day. The results show that, the temperature and humidity at the interface between the brick and cement mortar are seriously affected by the changes of outdoor temperature and humidity, and the relative humidity at this interface keeps more than 80% for a long-term, which can easily trigger the growth of mould. The temperature and humidity at the interface between the brick and cement plaster change a little, and they are affected by the changes of indoor temperature and humidity. The temperature and humidity at the interface of the wall whose interior surface is affixed with a foam plastic wallpaper are generally higher than those of the wall without wallpaper. The heat transfer and moisture transfer in the envelope are coupled strongly.
摘要:
The target contour extraction is one of key questions in computer vision. Because of its intrinsic limitations, the traditional C-V method can not meet the requirements of inclusion image contour extraction. To overcome this shortcoming, this paper introduces image overlay to make some improvements on the C-V methods, which is based on simplified Mumford-Shah, and compares the different contour extraction results caused by traditional method and improved C-V method. The results vindicate the efficiency and feasibility of improved C-V method.