期刊文献+
共找到41篇文章
< 1 2 3 >
每页显示 20 50 100
浮控型拖网模型试验
1
作者 杜守恩 《海洋渔业》 CSCD 北大核心 1991年第6期259-261,共3页
在我国海洋渔业中,机轮底拖网是主要渔具,其捕捞对象以近海底层鱼类为主.由于作业方式较单一,近海底层鱼类资源受到破坏,而中上层鱼类如鯷、鲱、鲐、沙丁鱼等及东黄海的主要捕捞对象如马面纯、带鱼、乌贼等具有垂直洄游或栖息水层变动... 在我国海洋渔业中,机轮底拖网是主要渔具,其捕捞对象以近海底层鱼类为主.由于作业方式较单一,近海底层鱼类资源受到破坏,而中上层鱼类如鯷、鲱、鲐、沙丁鱼等及东黄海的主要捕捞对象如马面纯、带鱼、乌贼等具有垂直洄游或栖息水层变动的习性,而中上层鱼类资源尚未得到充分开发利用. 展开更多
关键词 拖网 模型试验 浮控
下载PDF
一种浮控恒流器设计与实践
2
作者 钟敏 《装备制造技术》 2021年第5期190-193,215,共5页
在排水领域中,流量控制是一个重要的环节。国内恒定流量控制设备主要集中在医药设备和液压设备领域,而排水领域流量控制设备还是停留在调流闸门和一些简单的浮控装置上,针对排水领域流量控制问题,提出了一种浮控恒流器,可以根据排口工... 在排水领域中,流量控制是一个重要的环节。国内恒定流量控制设备主要集中在医药设备和液压设备领域,而排水领域流量控制设备还是停留在调流闸门和一些简单的浮控装置上,针对排水领域流量控制问题,提出了一种浮控恒流器,可以根据排口工况不同,自动调整排口开度,达到旱天正常排水及雨天恒流排水的功能,同时具备自动清除阻塞和流量控制精度高等特点,具有广泛的应用前景。 展开更多
关键词 浮控 恒流器 自动疏通堵塞
下载PDF
浮充型阀控铅酸蓄电池失效模式探讨 被引量:5
3
作者 孙玉生 刘玉辉 +1 位作者 舒达 王学志 《电池工业》 CAS 2003年第2期56-59,共4页
分析了浮充型阀控铅酸蓄电池(VRLAB)的失效原因以及相应的解决办法;认为,正极板栅的腐蚀与生长,负极活性物质的板结收缩和孔率降低以及负极有机膨胀剂的降解和损失、极耳和汇流排的腐蚀等因素是导致浮充型VRLAB失效的主要原因。
关键词 充型阀铅酸蓄电池 失效模式 失效机理 正极板栅 板栅合金 VRLAB
下载PDF
浮板型稳油控水阀仿真分析及应用 被引量:1
4
作者 李效波 王圣虹 +1 位作者 朱春明 周伯年 《海洋石油》 CAS 2020年第2期52-56,共5页
为了掌握浮板型稳油控水阀的控水性能,通过数值仿真计算的方式研究了控水阀在纯水、不同黏度纯油和不同含水率的油水混合液等条件下的稳油控水效果,并通过实际油田高含水井生产动态进行了现场稳油控水效果验证。结果表明,浮板型稳油控... 为了掌握浮板型稳油控水阀的控水性能,通过数值仿真计算的方式研究了控水阀在纯水、不同黏度纯油和不同含水率的油水混合液等条件下的稳油控水效果,并通过实际油田高含水井生产动态进行了现场稳油控水效果验证。结果表明,浮板型稳油控水阀具有良好的稳油控水效果。仿真计算分析为稳油控水阀的性能评价提供了有效的分析和评价手段,为今后控水新产品的研发和评价提供了有效手段和有力保障。 展开更多
关键词 板型稳油水阀 数值仿真计算 黏度 含水率 Q-ΔP特性曲线
下载PDF
大直径长距离输水钢管整体沉放可控浮箱和支撑吊装平台系统技术研究
5
作者 于孝民 韩立军 +2 位作者 方建国 丁北斗 肖乃强 《江苏水利》 2017年第5期41-44,共4页
在基本无流速的深水湖区中,施工平台、大型起吊设备进场困难,采用固定式施工平台或船舶等组装拼接成的浮式施工平台,已无法满足施工需求,本文以中运河原水管道沉管工程施工为背景,建构水上可控浮箱、吊装和支撑平台的原位制管沉放系统,... 在基本无流速的深水湖区中,施工平台、大型起吊设备进场困难,采用固定式施工平台或船舶等组装拼接成的浮式施工平台,已无法满足施工需求,本文以中运河原水管道沉管工程施工为背景,建构水上可控浮箱、吊装和支撑平台的原位制管沉放系统,设计其子结构系统,实现大型输水管道的水上运输、拼接和沉放体系。 展开更多
关键词 输水管 整体沉放 支撑吊装平台系统
下载PDF
大直径长距离输水管沉管施工技术研究 被引量:9
6
作者 于孝民 丁北斗 +2 位作者 方建国 丁丽 冯大帅 《中国水利》 2018年第16期52-55,共4页
以徐州中运河原水管道沉管工程施工为例,系统分析了大型输水管施工特点及应对措施。将整个输水管化整为零,在岸边分段制作,并建构水上可控浮箱、吊装和支撑平台的原位制管沉放系统,对分段制作大型输水管道实现水上运输、拼接和沉放施工。
关键词 输水管 整体沉放 支撑吊装平台系统 骆马湖
下载PDF
Coupling vibration analysis of high-speed maglev train-viaduct systems with control loop failure 被引量:4
7
作者 GUO Wei CHEN Xue-yuan +7 位作者 YE Yi-tao HU Yao LUO Yi-kai SHAO Ping HUANG Ren-qiang WANG Xu-yixin GUO Zhen TAN Sui 《Journal of Central South University》 SCIE EI CAS CSCD 2022年第8期2771-2790,共20页
The risk of failure of the control loop can occur when a high-speed maglev train runs on viaduct.Meanwhile,the failure of the levitation magnets which balances the gravity of the maglev train could cause the train col... The risk of failure of the control loop can occur when a high-speed maglev train runs on viaduct.Meanwhile,the failure of the levitation magnets which balances the gravity of the maglev train could cause the train collision with track.To study the dynamic response of the train and the viaduct when the levitation magnet control loop failure occurs,a high-speed maglev train-viaduct coupling model,which includes a maglev controller fitted by measured force-gap data and considers the actual structure of train and viaduct,is established.Then the accuracy and effectiveness of the established approach are validated by comparing the computed dynamic responses and frequencies with the measurement results.After that,the dynamic responses of maglev train and viaduct are discussed under normal operation and control loop failures,and the most disadvantageous combination of control loop failures is obtained.The results show that when a single control loop fails,it only has a great influence on the failed electromagnet,and the maglev response of adjacent electromagnets has no obvious change and no collision occurs.But there is a risk of rail collisions when the dual control loop fails. 展开更多
关键词 high-speed maglev train control loop failure coupling vibration maglev control
下载PDF
Disturbance decoupled fault diagnosis for sensor fault of maglev suspension system 被引量:6
8
作者 李云 李杰 +1 位作者 张耿 田文静 《Journal of Central South University》 SCIE EI CAS 2013年第6期1545-1551,共7页
A disturbance decoupled fault diagnosis strategy is proposed.This disturbance decoupled fault diagnosis is both robust to disturbances and sensitive to sensor faults of magnetic levitation control system.First,a robus... A disturbance decoupled fault diagnosis strategy is proposed.This disturbance decoupled fault diagnosis is both robust to disturbances and sensitive to sensor faults of magnetic levitation control system.First,a robust controller based on a novel disturbance observer is devised to improve the disturbance attenuation ability,which greatly enhances the robustness of the system.Second,a fault reconstruction technique with adaptive method is presented,along with a strict verification for guaranteeing the robustness of fault.This fault reconstruction technique provides an accurate sensor fault reconstruction.From the results of simulation and experiments conducted on the CMS-04 maglev train,the integrated strategy is robust to model uncertainties of the system and the fault reconstruction algorithm is able to reconstruct the dynamic uncertain faults. 展开更多
关键词 maglev system suspension control robust control disturbance observer tault reconstruction
下载PDF
A Novel Energy-regenerative Active Suspension for Vehicles 被引量:9
9
作者 郑雪春 喻凡 张勇超 《Journal of Shanghai Jiaotong university(Science)》 EI 2008年第2期184-188,共5页
In order to regenerate electric power from the vibration excited by road unevenness,a novel energy- regenerative active suspension for vehicles was proposed with the description of its structure and its working princi... In order to regenerate electric power from the vibration excited by road unevenness,a novel energy- regenerative active suspension for vehicles was proposed with the description of its structure and its working principle with two modes switched in different operating conditions.Then,the novel active system was modeled and simulated to show the performance improvement in ride comfort in its electrical motor mode.Finally,the performance tests of the actuator prototype were carried out,which proves its capability for damping in its regenerative braking mode.The research results can provide useful guidance for the similar electrical active suspension design and development. 展开更多
关键词 active suspension control algorithm energy regeneration vehicle dynamics
下载PDF
Self-excited vibration problems of maglev vehicle-bridge interaction system 被引量:12
10
作者 李金辉 李杰 +1 位作者 周丹峰 余佩倡 《Journal of Central South University》 SCIE EI CAS 2014年第11期4184-4192,共9页
The self-excited vibration problems of maglev vehicle-bridge interaction system were addressed, which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the... The self-excited vibration problems of maglev vehicle-bridge interaction system were addressed, which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the whole system. Firstly, the coupled model containing the quintessential parts was built, and the mechanism of self-excited vibration was explained in terms of energy transmission from levitation system to bridge. Then, the influences of the parameters of the widely used integral-type proportion and derivation(PD) controller and the delay of signals on the stability of the interaction system were analyzed. The result shows that the integral-type PD control is a nonoptimal approach to solve the self-excited vibration completely. Furthermore, the differential-type PD controller can guarantee the passivity of levitation system at full band. However, the differentiation of levitation gap should be filtered by a low-pass filter due to noise of gap differentiation. The analysis indicates that a well tuned low-pass filter can still keep the coupled system stable. 展开更多
关键词 maglev vehicle-bridge interaction system self-excited vibration energy
下载PDF
Saturation influence of control voltage on maglev stationary self-excited vibration 被引量:3
11
作者 李金辉 李杰 余佩倡 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第8期1954-1960,共7页
This work addresses the saturation influence of control voltage on the occurring of self-excited vibration of maglev vehicle-bridge interaction system, which greatly degrades the stability of the levitation control, d... This work addresses the saturation influence of control voltage on the occurring of self-excited vibration of maglev vehicle-bridge interaction system, which greatly degrades the stability of the levitation control, decreases the ride comfort, and restricts the cost of the whole system. Firstly, the interaction model of vehicle-bridge system is developed. Based on the interaction model, the relationship between the control voltage and vibration frequency is solved. Then, the variation of the effective direct component and fundamental harmonic are discussed. Furthermore, from the perspective of energy transmission between the levitation system and bridge, the principle underlying the self-excited vibration is explored, and the influence on the stability is discussed. Finally, in terms of the variation of the characteristic roots, the influence is analyzed further and some conclusions are obtained. This study provides a theoretical guidance for mastering the self-excited vibration problems. 展开更多
关键词 MAGLEV LEVITATION SATURATION self-excited vibration
下载PDF
Potential control flotation of galena in strong alkaline media 被引量:5
12
作者 顾帼华 胡岳华 +2 位作者 邱冠周 王晖 王淀佐 《Journal of Central South University of Technology》 2002年第1期16-20,共5页
The electrochemical oxidation of galena in collectorless and collector flotation systems, particularly in strong alkaline media, was studied. The results show that, with pH value higher than 12.5 and potentials below ... The electrochemical oxidation of galena in collectorless and collector flotation systems, particularly in strong alkaline media, was studied. The results show that, with pH value higher than 12.5 and potentials below 0.17 V, the oxidation products of galena are elemental sulfur and HPbO - 2. Elemental sulfur was present on the mineral surface in excess of oxidized lead species due to dissolution of HPbO - 2, which is beneficial to the flotation of galena. Under the same conditions, sphalerite and pyrite were depressed as a result of significant surface oxidation. Diethyldithiocarbamate (DDTC) was found to be the most suitable collector for galena flotation in strongly alkaline media. The very potential produced hydrophobic PbD 2-the surface reaction product of DDTC with galena, is 0 to 0.2 V. Meantime DDTC can depress the surface over oxidation of galena. Investigations also indicate that, in the range of -0.9 V to 0.6 V, hydrophobic PbD 2 can be firmly adsorbed on galena. 展开更多
关键词 GALENA potential control flotation COLLECTOR
下载PDF
Research on Dynamic Model's Building of Active Magnetic Suspension Systems 被引量:4
13
作者 施建 颜国正 +1 位作者 李黎川 王坤东 《Journal of Donghua University(English Edition)》 EI CAS 2006年第3期131-135,共5页
An experimental method is introduced in this paper to build the dynamics of AMSS (the active magnetic suspension system), which doesn’t depend on system’s physical parameters. The rotor can be reliably suspended und... An experimental method is introduced in this paper to build the dynamics of AMSS (the active magnetic suspension system), which doesn’t depend on system’s physical parameters. The rotor can be reliably suspended under the unit feedback control system designed with the primary dynamic model obtained. Online identification in frequency domain is processed to give the precise model. Comparisons show that the experimental method is much closer to the precise model than the theoretic method based on magnetic circuit law. So this experimental method is a good choice to build the primary dynamic model of AMSS. 展开更多
关键词 active magnetic suspension feedback control dynamic model building experimental method
下载PDF
Efficacy of Difenoconazole-azoxystrobin 32.5% SC in Treatment of Rice Sheath Blight and Its Application Technology 被引量:2
14
作者 李海亮 王会福 余山红 《Agricultural Science & Technology》 CAS 2014年第9期1589-1592,共4页
[Objective] The efficacy of difenoconazole-azoxystrobin 32.5% SC for rice sheath blight and its application technology were discussed in this research. [Method] Three surveys were carried out. There were 5 fixed test ... [Objective] The efficacy of difenoconazole-azoxystrobin 32.5% SC for rice sheath blight and its application technology were discussed in this research. [Method] Three surveys were carried out. There were 5 fixed test clumps in each plot. The number of total plants and disease plants and disease progression in each fixed clump were recorded. The correlation effectiveness was calculated based on the growth rate of disease index. Significance analysis was performed with Dun- can's new multiple range method (DMRT). [Result] The difenoconazole-azoxystrobin 32.5% SC had a good efficacy for rice sheath blight, and its efficacy increased with the increase of dose. If sprayed according to the dose of 450 ml/hm2 5 days before the beginning of heading stage of rice, difenoconazole-azoxystrobin 32.5% SC would have better effects on controlling rice sheath blight with correlation effectiveness reaching up to 95.14%, which was 2.06% higher than that of control drug (trifloxys- trobin-tebuconazole 75% WG, 225 g/hm2). [Conclusion] Treated with difenoconazole- azoxystrobin 32.5% SC with dose of 450 ml/hm2, rice would have green upper leaves and less yellow middle and lower leaves. Moreover, the yield was in- creased significantly. The difenoconazole-azoxystrobin 32.5% SC had good safety. Therefore, difenoconazole-azoxystrobin 32.5% SC had a good application prospect in production. 展开更多
关键词 Difenoconazole-azoxystrobin 32.5% SC Rice sheath blight Controlling efficiency SAFETY
下载PDF
SINGULAR PERTURBATION APPROACH TO MOVING MASS CONTROL OF BUOYANCY-DRIVEN AIRSHIP IN 3-D SPACE 被引量:1
15
作者 吴小涛 Claude H Moog 胡跃明 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2011年第4期343-352,共10页
The attitude control problem and the guidance problem are solved in 3-D for a buoyancy-driven airship actuated by the combined effects of an internal air bladder which modulates the airshiprs net weight and of two mov... The attitude control problem and the guidance problem are solved in 3-D for a buoyancy-driven airship actuated by the combined effects of an internal air bladder which modulates the airshiprs net weight and of two moving masses which modulate its center of mass. A simple and clear modeling is introduced to derive the 8 degree of freedom (DOF) mathematical model. Nonlinear control loops are derived through maximal feedback linearization with internal stability for both dynamics in the longitudinal plane and in the lateral plane. Based on a singular perturbation approach, the superposition of these two control actions in the longitudinal plane and in the lateral plane is shown to achieve the control of the dynamics in 3-D space. The simulations of the airship tracking specified attitude, moving direction and speed in 3-D space are presented. 展开更多
关键词 buoyancy-driven AIRSHIP nonlinear control 3-D singular perturbation
下载PDF
A practical robust nonlinear controller for maglev levitation system 被引量:5
16
作者 李金辉 李杰 张耿 《Journal of Central South University》 SCIE EI CAS 2013年第11期2991-3001,共11页
In order to explore the precise dynamic response of the maglev train and verify the validity of proposed controller,a maglev guideway-electromagnet-air spring-cabin coupled model is developed in the first step.Based o... In order to explore the precise dynamic response of the maglev train and verify the validity of proposed controller,a maglev guideway-electromagnet-air spring-cabin coupled model is developed in the first step.Based on the coupled model,the stresses of the modules are analyzed,and it is pointed out that the inherent nonlinearity,the inner coupling,misalignments between the sensors and actuators,and external disturbances are the main issues that should be considered for the maglev engineering.Furthermore,a feedback linearization controller based on the mathematical model of a maglev module is derived,in which the nonlinearity,coupling and misalignments are taken into account.Then,to attenuate the effect of external disturbances,a disturbance observer is proposed and the dynamics of the estimation error is analyzed using the input-to-state stability theory.It shows that the error is negligible under a low-frequency disturbance.However,at the high-frequency range,the error is unacceptable and the disturbances can not be compensated in time,which lead to over designed fluctuations of levitation gap,even a clash between the upper surface of electromagnet and lower surface of guideway.To solve this problem,a novel nonlinear acceleration feedback is put forward to enhancing the attenuation ability of fast varying disturbances.Finally,numerical comparisons show that the proposed controller outperforms the traditional feedback linearization controller and maintains good robustness under disturbances. 展开更多
关键词 dynamic robust nonlinear DECOUPLING separation levitation system MAGLEV
下载PDF
Nonlinear Control of Magnetic Bearings 被引量:1
17
作者 Khac Duc Do Dang Hoe Nguyen Thanh Binh Nguyen 《Journal of Measurement Science and Instrumentation》 CAS 2010年第1期10-16,共7页
In this paper, recent results controling nonlinear systems with output tracking error constmints are applied to the design of new tracking controllers for magnetic bearings. The proposed controllers can force the roto... In this paper, recent results controling nonlinear systems with output tracking error constmints are applied to the design of new tracking controllers for magnetic bearings. The proposed controllers can force the rotor to track a bounded and sufficiently smooth reference trajectory asymptotically and guarantee non-contactedness betweea the rotor and the stator of the magnetic beadngs. Simulation results are included to illustrate the effectiveness of the propsed controllers. 展开更多
关键词 nonlinear system output constraint bockstepping L yapunov method
下载PDF
Depth control for a deep-sea self-holding intelligent buoy system based on active disturbance rejection control method 被引量:1
18
作者 QIU Zu-rong WANG Qiang +2 位作者 YANG Shao-bo LI Hong-yu LI Xing-fei 《Journal of Measurement Science and Instrumentation》 CAS CSCD 2020年第4期307-316,共10页
The net buoyancy of the deep-sea self-holding intelligent buoy(DSIB)will change with depth due to pressure hull deformation in the deep submergence process.The net buoyancy changes will affect the hovering performance... The net buoyancy of the deep-sea self-holding intelligent buoy(DSIB)will change with depth due to pressure hull deformation in the deep submergence process.The net buoyancy changes will affect the hovering performance of the DSIB.To make the DSIB have better resistance to the external disturbances caused by the net buoyancy and water resistance,a depth controller was designed to improve the depth positioning based on the active disturbance rejection control(ADRC).Firstly,a dynamic model was established based on the motion analysis of the DSIB.In addition,the extended state observer(ESO)and nonlinear state error feedback controller were designed based on the Lyapunov stability principle.Finally,semi-physical simulations for the depth control process were made by using the ADRC depth controller and traditional PID depth controller,respectively.The results of the semi-physical simulations indicate that the depth controller based on the ADRC can achieve the predefined depth control under the external disturbances.Compared with the traditional PID depth controller,the overshoot of the ADRC depth controller is 1.74%,and the depth error is within 0.5%.It not only has a better control capability to restrain the overshoot and shock caused by the external disturbances,but also can improve intelligence of the DSIB under the depth tracking task. 展开更多
关键词 deep-sea self-holding intelligent buoy(DSIB) active disturbance rejection control(ADRC) depth control buoyancy change pressure hull deformation
下载PDF
Genetic Optimization Algorithm of PID Decoupling Control for VAV Air-Conditioning System 被引量:3
19
作者 王江江 安大伟 +1 位作者 张春发 荆有印 《Transactions of Tianjin University》 EI CAS 2009年第4期308-314,共7页
Variable-air-volume (VAV) air-conditioning system is a multi-variable system and has multi coupling control loops. While all of the control loops are working together, they interfere and influence each other. A multiv... Variable-air-volume (VAV) air-conditioning system is a multi-variable system and has multi coupling control loops. While all of the control loops are working together, they interfere and influence each other. A multivariable decoupling PID controller is designed for VAV air-conditioning system. Diagonal matrix decoupling method is employed to eliminate the coupling between the loop of supply air temperature and that of thermal-space air temperature. The PID controller parameters are optimized by means of an improved genetic algorithm in floating point representations to obtain better performance. The population in the improved genetic algorithm mutates before crossover, which is helpful for the convergence. Additionally the micro mutation algorithm is proposed and applied to improve the convergence during the later evolution. To search the best parameters, the optimized parameters ranges should be amplified 10 times the initial ideal parameters. The simulation and experiment results show that the decoupling control system is effective and feasible. The method can overcome the strong coupling feature of the system and has shorter governing time and less over-shoot than non-optimization PID control. 展开更多
关键词 genetic algorithm decoupling control PID control variable air volume air-conditioning system
下载PDF
Coordinated optimization setting of reagent dosages in roughing-scavenging process of antimony flotation 被引量:3
20
作者 CAO Bin-fang XIE Yong-fang +2 位作者 GUI Wei-hua YANG Chun-hua LI Jian-qi 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第1期95-106,共12页
Considering the influence of reagent adjustment in different flotation bank on the final production index and the difficulty of establishing an effective mathematical model,a coordinated optimization method for dosage... Considering the influence of reagent adjustment in different flotation bank on the final production index and the difficulty of establishing an effective mathematical model,a coordinated optimization method for dosage reagent based on key characteristics variation tendency and case-based reasoning is proposed.On the basis of the expert reagent regulation method in antimony flotation process,the reagent dosage pre-setting model of the roughing–scavenging bank is constructed based on case-based reasoning.Then,the sensitivity index is used to calculate the key features of reagent dosage.The reagent dosage compensation model is constructed based on the variation tendency of the key features in the roughing and scavenging process.At last,the prediction model is used to finish the classification and discriminant analysis.The simulation results and industrial experiment in antimony flotation process show that the proposed method reduces fluctuation of the tailings indicators and the cost of reagent dosage.It can lay a foundation for optimizing the whole process of flotation. 展开更多
关键词 froth flotation image features optimization setting coordinated optimization
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部