共查询到20条相似文献,搜索用时 31 毫秒
1.
This paper discusses the structure, design and key techniques of testing system, and expounds the design and development of hardware and software based on virtual instrument technology. The design of hardware includes signal conditioning module and data acquisition module. The design of software includes interface program and upper layer program. Combining the hardware and software effectively, a testing system for ABS test-bed is set up, which has multifunctions of developing, debugging, inspecting and performance valuing to ABS. Having crucial meaning in engineering, the development of this testing system will make ABS tested in the lab mainly, thus improve the security and make the test more economical. 相似文献
2.
The auto controlling based on PLC system realized the identifying of coking number and the accurate position.In this system the identifying of coking number was reached with the schematic binary system of PLC and the assistant of proximity sensor.With RS485 ,the digital was used for transducer controlling port which drive the motor and the high speed counter, AD61, was used for feedback adjusting the offset.The discrete digital increasing PID control algorithm compensating the position errors is discussed to arrive at the accuracy auto position.With the module ,RS485,we realize the serial communication and the report forms managing between the PLLC system and the computer.The technique can achieve the object of automatic control accuracy in practices. 相似文献
3.
CNC system is gradually developing toward flexible, component modular and re-configurable of open CNC system's structure. It's beginning a research direction in open CNC system with the software reuse and re-configurable technology. Based on the expound of concepts and characteristics of component technology, open CNC system's characteristics are analyzed based on COM and open CNC system is divided into several components. With the characteristics of binary language irrelevant, thread transparent, re-configurable and normative interface of COM technology, open CNC system's interpolate-compensation component in interpolate-compensation component achieved, interface designed and object created are researched. Better effects are achieved by connecting the interpolate-compensation component with the other CNC components. At the same time, the CNC component's real-time control problem is analyzed. 相似文献
4.
Vibration & Noise Analysis on Double-ring Gear Reducer 总被引:1,自引:0,他引:1
Double-ring gear reducer with Central inputting shaft is studied. The basic structure of reducer as well as testing equipment, probe spot and testing method of Structure-borne noise and air-borne noise is presented. Based on frequency spectrum of each point, amplitude spectrum of structure-borne noise and testing results of air-borne noise, the authors analyze the vibration characters and latent faults of double-ring gear reducer, coming to the value and the cause of the noise, providing theoretical basis for proper design of the double-ring gear reducer and method of reducing its vibration and noise. 相似文献
5.
A method of detecting the signal frequency which is disturbed by the noise based on the autonomous chaotic system is proposed. A signal with noise was added to an autonomous chaotic system, and then a negative feedback was imposed to it. The feedback gain was appropriately adjusted, so as to let the noisy system orbit be a limit cycle. The number of times that the orbit went directly through a plane was calculated by loop phase technology, and the vibration frequency was found according to it. The frequency of system is determined by the frequency of the test signal, yet free from noise, so the frequency of the test signal is the vibration frequency of the system. Simulation results further demonstrate the effectiveness of the method. 相似文献
6.
The two-way branch exhaust pipe shield is the main source of surface radiate noise of a vehicle's engine.(Using) the finite element analysis software ANSYS,a finite element model of the shield is established,and then the(modal) analysis is done theoretically with this model,the result is consistent with the experiment.The result shows that this finite element model can be used for the next structual dynamic characteristics analysis.With this model,the relationship of structural parameter,structural style of the shield and the corresponding vibrative modal is analyzed.The(optimal) improved measures are adopted which is based on the practical structure of the shield.The analysis of the(improved) structure shows that the increase of natural vibration frequency is visible,the vibration noise of the shield is suppressed distinctly. 相似文献
7.
The exhaust manifold cover is the main source of surface radiate noise of a 6 360 vehicle's engine.By using the finite element analysis technology,a finite element model of the cover is established,and then the modal analysis is done theoretically with this model,the result is consistent with the experiment.On this basis,the transient response of the cover under the excitation of engine block's vibration is analyzed.The result show that the free edge is the main source of radiate noise,because its normal velocity is maximal.The improved measures are adopted which is based on the practical structure of the cover.The analysis of the improved structure shows that the measures are effective,the radiate noise of the cover is decreased distinctly. 相似文献
8.
The establishment of the competition legal system is the response to the social and economical reality. The perfection of the competition legal system needs the support of economic theory. Therefore, analyzing the competition from the law and economic perspective is propitious to perfect the regulation of competition in the law system constantly, guarantee and promote competition, and thus to establish and maintain reasonable and efficient competition order, promote market-economy developing prosperously and harmoniously. The paper uses the study methods of economical and comparative analyze, explore the sorts of competition and their effectiveness, believe that the perfection of the competition legal system should firstly definite that its adjust object is the effective competition with monopoly factor; though the exemption of competition cant be avoid, it continuously appears shrinking trend. The competition legal system will play a more important role in the economical life. 相似文献
9.
洱海流域农业生态补偿研究 总被引:2,自引:0,他引:2
以云南洱海流域为研究对象,针对农业非点源污染防控,依托项目示范对洱海流域农业生态补偿机制进行研究。以大理州地方政府为补偿主体,流域内农户为补偿对象,试行资金补贴、技术补偿、智力补偿等补偿方式,实施种植业产业结构调整和畜禽粪污的资源化利用,有效削减了氮、磷等污染物排放量,降低了畜禽废弃物对洱海水体的污染。通过宣传、培训,加强了农民群众和农技人员在思想上的认识,产生了良好且积极的示范效果。最后提出了加大补偿力度、扩大补偿范围、细化补偿标准、逐步构建适合洱海流域农业不断发展的农业生态补偿机制等建议。 相似文献
10.
Considering Object oriented design, abstract mechanism of object and technology of procedure design in ObjectARX are introduced.By analyzing characteristics of power network, the puper it elaborates process of definition special object by using of open structure of AutoCAD inner database , base class provided by ARX and mechanism of calss inheritance and derivative. The class definition of elemens is also given in power system as well. Technology of data exchange is also elaborated. On this base ,object models of power CAD are constructed.Date exchange between PWCAD and the external database is also realized. 相似文献
11.
In order to study the vibration characteristics and radiation noise of wind power speed-increase gearbox, a torsional vibration model of wind power speed-increase gearbox is established based on the analysis of supporting stiffness of bearing and contact stiffness of gear pairs. By solving the vibration differential equation with the help of Matlab, the frequency and corresponding vibration mode are obtained. With taking stiffness excitation, error exaction and meshing impact exaction into account, the dynamic finite element model of speed-increase gearbox is set up, and the dynamic response simulation is carried out. Regarding vibration displacement of the nodes on gearbox surface as boundary condition, an acoustic boundary element model of speed-increase gearbox is built. The surface acoustic pressure of gearbox and the radiation noise of field points are solved by the direct boundary element method. The results show that there is a great difference between torsion frequency and excitation frequency of wind power speed-increase gearbox, and so the resonance doesn't occur. The maximum structural noise and radiation noise mainly appear near the double octave of the gears meshing frequency of high-speed grade. 相似文献
12.
Electromagnetic radiation, which is caused by the engine ignition system, is the most powerful electromagnetic interference (EMI) source in the vehicles, as well as the main reason of most electronic control unit (ECU) malfunction. In order to reduce interference from ignition noise on ECU, we use optical isolation technology to isolate electrical connections between the interference source and the control circuit. The formation mechanism of the ignition system EMI is analyzed. The possibility of suppressing ignition system EMI with optical isolation technology is discussed. Then, as a result we design an experimental platform of suppressing ignition system EMI. The experimental results show that the effect of suppressing ignition noise, in 20~100 MHz frequency band, is obvious after applying optical isolation circuit. It can address the issue of automotive EMC. 相似文献
13.
Aiming at the problem that the gain amplitude is hard to identify in advance and the gain value can not be set properly, an auto gain control (AGC) strategy using Kalman filter is presented to deal with the uncertainty in vibration acquire system. The design principles, algorithms and circuit implementation are described. The experimental results show that this method can not only control auto gain in dynamic data acquiring system, but also get wide gain amplitude range without setting the initial value. It has important practical application value in high dynamic range data acquisition. 相似文献
14.
The device of testing rotational speed is very important to dynamic-balancing testing system.Requirements for the device of testing rotational speed include: high-accuracy,stabilization,credibility,and shorter testing time.To the development of high-speed rotor dynamic-balancing testing system based on DSP(digital signal processing),the way of picking-up rotator reference signal,testing rotator speed based on DSP and the design of software are introduced.This new way of testing rotational speed in high-speed rotor dynamic-balancing testing system based on DSP is accurate,simple,convenient,the range of rotational speed which can test is broad,and the new way is very suitable to pick-up the amplitude and phase of vibration caused by unbalanced amount. 相似文献
15.
农业科技评价及其问题与建议 总被引:7,自引:0,他引:7
农业科技评价是指根据委托者的明确目的,由专门的评价机构和人员依据大量的客观事实和数据,遵循一定的原则、程序和标准,运用科学、可行的方法,对科技政策、科技计划、科技发展领域、科技项目、科技成果、科技机构、科技人员以及与科技活动有关的行为,进行专业化咨询与评判的活动。其目的在于减少农业科技决策的盲目性和随意性,有重点、有效率地分配农业科技资源,改善和提高农业科技决策的质量和水平,通过公开、透明的评价标准、程序及评价结果,接受各方监督,创造民主、公平、竞争的农业科研环境。农业科技评价具有9项功能,需要遵循8项标准。当前农业科技评价存在的主要问题是:评价大多只注重一头一尾,而缺乏对科技活动本身的过程性评价和整体性评价;第三方评价制度亟待建立;定位不够明确;评价能力有待提高;评价指标体系存在误区。为此,建议采取以下对策:落实科技评价相关规定,建立健全农业科技评价管理制度和操作规范;建立健全农业科技评价支持系统,培育农业科技评价人力资源;加强对符合农业科研现状的评价指标体系和方法的研究;评价工作要抓全程;建立健全农业科技评价激励制度,充分发挥评价的激励作用;建立与国际接轨的农业科技评价制度。 相似文献
16.
The mesh stiffness of gear tooth is simulated by spring elements, the connected bolt between various housings are simplified as bar elements, and the sliding bearing and rolling bearing are simplified as spring dumping elements. Based on them, the gear-shaft-bearing-housing coupled finite element model and boundary element model of GWC6066 marine gearbox are established. Finally, the dynamic response under internal dynamic excitation is analyzed and the vibration severity, structural-borne noise and air-borne noise of the gear system are forecasted. Through the experimental modal analysis of gear system, and the test of vibration response and air pressure, the natural frequencies, vibration severity, structural-borne noise and air-borne noise are obtained. Compared with numerical results, two results show good agreement. 相似文献
17.
Joints are crucial factors in rock masses engineering,so using stress waves to invert joint attitude is a valuable practice.The stress wave emitted from a vibration source is reflected by joints and returns to the ground.A formula to calculate the reflected wave travel time was deduced using analytic geometry theory.In the formula,a direct relationship was established between a joint's real dip angle,real dip direction and the travel time at test spots on the ground.The reflected wave's isotravel time circle described by the formula has a clear conception and a definite meaning.Using the program on the MATLAB platform,this formula can be applied to invert the joint attitude by searching the center of the circle based on the measured travel time at the testing spots around the wave source. 相似文献
18.
Based on the neural networks, object oriented technique, artificial intelligence technique and computer networks, an intelligent fault diagnosis system of the power plant whose need of the operation is presented. The architecture of software system , hardware system and corresponding databases is designed. The software of collecting data is established. The intelligent fault diagnosis system based on neural networks and object oriented technique is also developed. The physical system operation has been shown that the method mentioned above is feasible and effective in practice. 相似文献
19.
为探索产业精准扶贫方法、更好推进四川产业精准扶贫,首次运用多重对应分析法进行了产业精准扶贫关联度分析,发现四川贫困县的地理位置、产业、技术需求环节、技术需求对象之间存在关联。川西、川南的企业对中药材加工技术需求意愿更强,川南、川东的专合组织对经济作物技术需求意愿更强,川西的政府部门对林业、特色水果、畜禽的种植或养殖技术需求意愿更强。提出了产业精准扶贫的任务是"产业定位精确、科技着力精准、技术服务精细",可通过"立足需求、对口支援、项目引导、企业带动"的路径实现,但要处理好生产与市场、政府与市场、创新与服务的关系。 相似文献
20.
Vehicle ignition system is the main electromagnetic interference source. Electromagnetic radiation produced by ignition system will produce the interference to electromagnetic environment around. It is necessary to study the electromagnetic interference (EMI) principle, noise paths and suppression method. We analyze the electromagnetic interference principle of ignition system, and harness trouble-shooting related to electromagnetic interference is also tested. Results show that the spark discharge between spark plug electrodes is the main interference source in ignition system. Then, the paths of conducted interference and the reason of radiated emission are discussed in detail. Finally, two kinds of power supply cord EMI filters are designed and implemented on the basis of analysis results. Experimental results indicate that the filter can reduce the noise of power-wire in broadband range. Simultaneously, the radiation emission performance from power wire is also reduced observably. The proposed mixing filter has been demonstrated in this paper to perform satisfactorily with excellent effectiveness in suppression of conducted EMI from 10 MHz to 110 MHz, and the object car can also pass the EMC standard tests. 相似文献