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基于水位检测的自调速风动潜水泵设计
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作者 阮学云 王鹏彧 +2 位作者 郑礼强 袁亮 胡晓峰 《矿山机械》 北大核心 2013年第12期66-69,共4页
通过对常规风动潜水泵增设气动控制系统与机械式水位检测装置,根据出口节流调速和浮力原理,研制出一种新型自调速风动潜水泵。该风动泵可避免泵体在空载条件下因涡轮转速过快而造成"飞车"现象,实现井下无人值守,可根据有无负... 通过对常规风动潜水泵增设气动控制系统与机械式水位检测装置,根据出口节流调速和浮力原理,研制出一种新型自调速风动潜水泵。该风动泵可避免泵体在空载条件下因涡轮转速过快而造成"飞车"现象,实现井下无人值守,可根据有无负载实现自动切换,是一种高效节能、低噪、安全可靠及便于安装维修的新型排水机具,尤其在含有瓦斯与煤尘的矿井中使用更加安全可靠。 展开更多
关键词 风动 潜水泵 自调速 水位检测
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大惯性转台准确定位的自调整控制方法 被引量:2
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作者 李战明 吴言华 陈若珠 《甘肃工业大学学报》 北大核心 2002年第2期65-68,共4页
对于大惯性转台的控制 ,提出了自调整控制算法 ,利用历史信息实现转台减速点的智能调整 ,给出了减速点计算公式 ,解决了大惯性转台快速运行与准确定位的矛盾 .利用Matlab对系统进行了建模仿真研究 ,得到了满意效果 ,证明了自调整算法的... 对于大惯性转台的控制 ,提出了自调整控制算法 ,利用历史信息实现转台减速点的智能调整 ,给出了减速点计算公式 ,解决了大惯性转台快速运行与准确定位的矛盾 .利用Matlab对系统进行了建模仿真研究 ,得到了满意效果 ,证明了自调整算法的有效性 . 展开更多
关键词 大惯性转台 自调速控制 定位 仿真 减速点 舞台设备
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碎石桩复合地基桩土应力比数值分析 被引量:2
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作者 赵明华 陶可 +2 位作者 唐英旺 赵明 陈昌富 《湖南交通科技》 2002年第4期17-18,共2页
通过对碎石桩复合地基桩土应力比随荷载变化规律的深入分析 ,提出了一种能较好拟合桩土应力比的自调整双曲线模型 ,与湖南省临长高速公路碎石桩复合地基实测结果比较 ,效果良好。
关键词 数值分析 碎石桩 复合地基 桩土应力比 自调速双曲线模型 公路
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基于液压力变化的防“飞车”风动涡轮潜水泵设计
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作者 王飞 阮学云 《液压与气动》 北大核心 2015年第1期69-71,77,共4页
风动潜水泵是一种常用的防爆型井下设备,其在空载时由于涡轮转速过快,容易引起"飞车"现象。通过对常规风动涡轮潜水泵增设由气动换向阀、节流阀等组成的气体控制系统,根据出口节流调速原理,研制一种基于排水口液压力变化而进... 风动潜水泵是一种常用的防爆型井下设备,其在空载时由于涡轮转速过快,容易引起"飞车"现象。通过对常规风动涡轮潜水泵增设由气动换向阀、节流阀等组成的气体控制系统,根据出口节流调速原理,研制一种基于排水口液压力变化而进行气动控制的新型自调速风动潜水泵。试验表明,该装置可避免风动泵在空载条件下而造成的"飞车"现象,可根据有无负载实现自动切换,是一种高效节能、低噪、安全可靠、便于安装维修的一种新型排水机具。 展开更多
关键词 风动潜水泵 自调速 出口节流 液压力变化
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Model of gas exchange dynamics for modified-atmosphere packages containing fresh produce
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作者 刘颖 李云飞 +1 位作者 王如竹 田平海 《Journal of Southeast University(English Edition)》 EI CAS 2005年第3期314-318,共5页
A model for modified-atmosphere packaging (MAP) systems containing fruits and vegetables was developed.The computer simulation was performed to predict the gas mass concentrations inside the packages and was success... A model for modified-atmosphere packaging (MAP) systems containing fruits and vegetables was developed.The computer simulation was performed to predict the gas mass concentrations inside the packages and was successfully verified by experiments with yellow peaches at 5,15 and 25 ℃ using two types of packaging films.A Michaelis-Menten type respiration model with noncompetitive inhibition mechanism due to CO2 was adopted while the respiration rates were measured with an improved permeable system method suitable for either steady or unsteady state.The applicability of the model in the design of MAP systems was demonstrated with a calculation to evaluate film specification and equilibrium concentrations of O2 and CO2 in the package containing yellow peaches. 展开更多
关键词 gas exchange dynamics modified-atmosphere package respiration rate yellow peach
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Predictive current control system of PMSM based on LADRC 被引量:2
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作者 Wang Xiaopeng Zhao Jun +1 位作者 Wang Bohui Li Baomin 《Journal of Southeast University(English Edition)》 EI CAS 2022年第3期227-234,共8页
For a permanent magnet synchronous motor(PMSM)model predictive current control(MPCC)system,when the speed loop adopts proportional-integral(PI)control,speed regulation is easily affected by motor parameters,resulting ... For a permanent magnet synchronous motor(PMSM)model predictive current control(MPCC)system,when the speed loop adopts proportional-integral(PI)control,speed regulation is easily affected by motor parameters,resulting in the inability to balance the system robustness and dynamic performance.A PMSM optimal control strategy combining linear active disturbance rejection control(LADRC)and two-vector MPCC(TV-MPCC)is proposed.Firstly,a mathematical model of a PMSM is presented,and the PMSM TV-MPCC model is developed in the synchronous rotation coordinate system.Secondly,a first-order LADRC controller composed of a linear extended state observer and linear state error feedback is designed to reduce the complexity of parameter tuning while linearly simplifying the traditional active disturbance rejection control(ADRC)structure.Finally,the conventional PI speed regulator in the motor speed control system is replaced by the designed LADRC controller.The simulation results show that the speed control system using LADRC can effectively deal with the changes in motor parameters and has better robustness and dynamic performance than PI control and similar methods.The system has a fast motor speed response,small overshoot,strong anti-interference,and no steady-state error,and the total harmonic distortion is reduced. 展开更多
关键词 permanent magnet synchronous motor(PMSM) two-vector model predictive current control linear active disturbance rejection control speed control system
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Discrete-Rate Adaptive Modulation with Variable Threshold for Distributed Antenna System in the Presence of Imperfect CSI 被引量:3
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作者 YU Xiangbin TAN Wenting +1 位作者 WU Binbin LI Yang 《China Communications》 SCIE CSCD 2014年第A01期31-39,共9页
Discrete-rate adaptive modulation (AM) scheme for distributed antenna system (DAS) with imperfect channel state information (CSI) is developed, and the corresponding performance is investigated in composite Rayl... Discrete-rate adaptive modulation (AM) scheme for distributed antenna system (DAS) with imperfect channel state information (CSI) is developed, and the corresponding performance is investigated in composite Rayleigh channel. Subject to target bit error rate (BER) constraint, an improved fixed switching threshold (FST) for the AM scheme is presented by means of tightly-approximate BER expression, and it can avoid the performance loss fxom conventional FST. Based on the imperfect CSI, the variable switching threshold (VST) is derived by utilizing the maximum a posteriori method. This VST includes the improved FST as a special case, and may lower the impact of estimation error on the performance. By the switching thresholds, the spectrum efficiency (SE) and average BER of the system are respectively derived, and resulting closed- form expressions are attained. With these expressions, the system performance can be effectively evaluated. Simulation results show that the derived theoretical SE and BER can match the simulations well. Moreover, the AM with the presented FST has higher SE than that with the conventional one, and the AM with VST can tolerate the large estimation error while maintaining the target BER. 展开更多
关键词 distributed antenna system adaptive modulation imperfect estimation variable thresholds
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Face Detection Technology Based on Robot Vision
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作者 Guxiong Li 《International Journal of Technology Management》 2015年第9期43-45,共3页
One being developed automatic sweep robot, need to estimate if anyone is on a certain range of road ahead then automatically adjust running speed, in order to ensure work efficiency and operation safety. This paper pr... One being developed automatic sweep robot, need to estimate if anyone is on a certain range of road ahead then automatically adjust running speed, in order to ensure work efficiency and operation safety. This paper proposed a method using face detection to predict the data of image sensor. The experimental results show that, the proposed algorithm is practical and reliable, and good outcome have been achieved in the application of instruction robot. 展开更多
关键词 face detection gray integral skin color model robot vision
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A SEMI-OPEN-LOOP CODING MODE SELECTION ALGORITHM BASED ON EFM AND SELECTED AMR-WB+ FEATURES
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作者 Hong Ying Zhao Shenghui Kuang Jingming 《Journal of Electronics(China)》 2009年第2期274-278,共5页
To solve the problems of the AMR-WB+(Extended Adaptive Multi-Rate-WideBand) semi-open-loop coding mode selection algorithm,features for ACELP(Algebraic Code Excited Linear Prediction) and TCX(Transform Coded eXcitatio... To solve the problems of the AMR-WB+(Extended Adaptive Multi-Rate-WideBand) semi-open-loop coding mode selection algorithm,features for ACELP(Algebraic Code Excited Linear Prediction) and TCX(Transform Coded eXcitation) classification are investigated.11 classifying features in the AMR-WB+ codec are selected and 2 novel classifying features,i.e.,EFM(Energy Flatness Measurement) and stdEFM(standard deviation of EFM),are proposed.Consequently,a novel semi-open-loop mode selection algorithm based on EFM and selected AMR-WB+ features is proposed.The results of classifying test and listening test show that the performance of the novel algorithm is much better than that of the AMR-WB+ semi-open-loop coding mode selection algorithm. 展开更多
关键词 Speech/Audio Semi-open-loop coding mode selection Features selection Energy Flat-ness Measurement(EFM)
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Location-adaptive transmission for indoor visible light communication 被引量:1
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作者 王春悦 王浪 迟学芬 《Optoelectronics Letters》 EI 2016年第1期69-73,共5页
A location-adaptive transmission scheme for indoor visible light communication(VLC) system is proposed in this paper.In this scheme,the symbol error rate(SER) of less than 10-3 should be guaranteed.And the scheme is r... A location-adaptive transmission scheme for indoor visible light communication(VLC) system is proposed in this paper.In this scheme,the symbol error rate(SER) of less than 10-3 should be guaranteed.And the scheme is realized by the variable multilevel pulse-position modulation(MPPM),where the transmitters adaptively adjust the number of time slots n in the MPPM symbol according to the position of the receiver.The purpose of our scheme is to achieve the best data rate in the indoor different locations.The results show that the location-adaptive transmission scheme based on the variable MPPM is superior in the indoor VLC system. 展开更多
关键词 LIGHT Light transmission LOCATION Pulse position modulation Transmissions
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