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针对时变转动惯量测量的问题,建立基于扭摆法的时变转动惯量测量模型,提出基于Hilbert变换的时变转动惯量计算方法。根据分析动力学的原理,利用第二类拉格朗日方程建立基于时变转动惯量的单自由度扭摆运动方程。对物体的角位移信号进行Hilbert变换并构造解析信号。利用角位移信号的瞬时角频率和包络信号计算扭摆运动的瞬时无阻尼固有频率。根据瞬时无阻尼固有频率求出物体的转动惯量。利用基于气浮转台的扭摆系统,对转动惯量线性变化的试验样件进行转动惯量测量。由于测量系统采用气浮转台,因此,消除机械摩擦力对转动惯量测量的影响。试验结果表明,试验样件的转动惯量测量值的相对误差小于0.5%,从而验证基于Hilbert变换的时变转动惯量测量方法的有效性。 相似文献
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提出一种用于测量不规则物体转动惯量的系统,该测量系统采用扭摆机构、光电传感器提取摆动周期信息,并对测量值进行详细分析和计算.文章从阻尼分析出发,介绍了扭摆机构振动模型的工作原理,阐述了3种阻尼情况,并导出了转动惯量的求解公式. 相似文献
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为提高扭摆法测量大型回转体转动惯量的测量精度,克服线性转动惯量测量模型及周期法转动惯量计算的弊端,开展了基于希尔伯特-黄变换(HHT)的转动惯量测量技术研究。建立了考虑摩擦阻力矩的非线性转动惯量测量模型,在此基础上,通过经验模态分解提取了角位移主分量,利用希尔伯特变换识别了扭摆系统的瞬时阻尼系数和瞬时无阻尼固有频率,最后利用最小二乘法拟合得到非线性模型参数,精确求解了转动惯量。研制了一套大型回转体转动惯量测量系统,对不同组合的标准件进行转动惯量测量试验,验证了基于HHT的转动惯量计算方法的可行性。大量试验测量结果表明,本系统转动惯量测量相对误差小于0.2%,测量精度显著优于传统的周期法测量结果。 相似文献
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基于扭摆法的弹体转动惯量测量系统及误差分析 总被引:1,自引:0,他引:1
穆继亮 《机械工程与自动化》2009,(1)
介绍了一种用于测量弹体转动惯量的系统,该测量系统利用扭摆机构、光电传感器提取摆动周期信息,由计算机组成的测量系统进行数据处理.阐述了系统的工作原理,推导了所需的计算公式,分析了产生测量误差的因素,进行了定量精度分析,并给出综合结论. 相似文献
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为了准确识别物体的转动惯量值,考虑了非线性空气阻尼和非线性恢复力对转动惯量识别的影响,建立了基于非线性动力学系统的扭摆振动模型,提出了基于Hilbert变换的转动惯量识别方法。首先,利用扭摆振动获得物体的角位移信号,通过对角位移信号进行Hilbert变换计算角位移信号的包络信号和瞬时相位;然后,利用包络信号和瞬时相位计算扭摆振动的瞬时无阻尼固有频率;最后,根据瞬时无阻尼固有频率识别物体的转动惯量。通过气浮转台实现物体的扭摆振动,利用基于Hilbert变换的算法识别试验样件的转动惯量。试验结果表明,试验样件转动惯量估计值的相对误差小于1%,从而验证了该识别方法的有效性。 相似文献
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采用非接触式的检测方法,研制了打孔水松纸透气度在线检测系统,并进行了系统硬件和软件的设计,硬件系统主要由稳定光源、传动单元、检测单元、清洁空气单元、计算机等组成,本系统克服了离线式事后检测有能及时反映生产过程中出现的透气度不满足工艺要求,不能实时跟踪透气度的波动等缺点,对此新型系统的实验研究表明:系统检测精度高,运行稳定,促进了国内在这一技术领域的研究水平。 相似文献
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动平衡数控去重系统及其关键技术的研究 总被引:2,自引:0,他引:2
为满足动平衡自动校正一体化技术的需求,采用嵌入式系统作为中心测控单元研制了一个动平衡数控去重系统。在对系统总体结构介绍的基础上,重点对电机转子加工模型和刀具自动定位技术等两个关键技术进行了研究。实际应用表明,系统方案合理、技术可行、具有较高的性价比。 相似文献
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Accurate mass flow measurement is very important in various monitoring and control applications. This paper proposes a novel method of fluid flow measurement by compensating the pressure drop across the ends of measuring unit using a compensating pump. The pressure drop due to the flow is balanced by a feedback control loop. This is a null-deflection type of measurement. As the insertion of such a measuring unit does not affect the functioning of the systems, this is also a non-disruptive flow measurement method. The implementation and design of such a unit are discussed. The system is modeled and simulated using the bond graph technique and it is experimentally validated. 相似文献
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自动包装线中的新型测控系统 总被引:4,自引:0,他引:4
介绍了一种新型的由PLC为主控单元,传感器、单片机、触摸屏及执行器件相互关联的测控系统,通过硬件和软件的设计分析,展示了此系统在机电一体化设备及自动线中的应用优势。 相似文献
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I. P. Shcherbakov S. D. Samuilov Yu. N. Bocharov 《Instruments and Experimental Techniques》2009,52(2):207-208
A simple unit for measuring electrical current in complex (including coaxial) circuit sections is considered. A conductor section of the basic measured circuit, to which a light-emitting diode, a galvanic cell, and a regulating resistor are connected, is used as a shunt. A signal from the light-emitting diode arrives at the measuring system. The unit is intended for measuring both large (kilo- and megaampere) and relatively small (up to several amperes) values of the direct, alternating, and pulsed current. 相似文献
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小型化弹丸速度测试系统 总被引:2,自引:2,他引:0
提出了一种基于光幕测速和单片机数据处理的小型化的弹丸速度测试系统。采用半导体激光器、光电探测器、原向反射屏形成大面积光幕测试区,当弹丸穿越光幕时,光通量的变化被光电探测器转变为电信号,经过比较电路后送入单片机进行数据处理,并由LED进行速度显示。文中对测试原理和测试系统的光学设计单元、信号处理单元及数据采集、显示单元进行了介绍,并对该系统进行了壬7.62mm弹丸速度测试,给出了测试数据。试验表明,该测速系统具有灵敏度高、体积小、成本低、使用方便、灵活、工作可靠等优点。 相似文献
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《Measurement》2014
A Supervisory Control and Data Acquisition (SCADA)/Programmable Logic Control (PLC) system is always used to control small industries like water treatment stations; electric power stations and irrigation systems. Oil and gas refineries generally rely on a Distributed Control System (DCS) to provide all process and equipment control functionality. In this paper, a SCADA/PLC system is used to control a whole oil refinery instead of the conventional control through DCS. The design and specific implementation method of a SCADA/PLC real system in an oil refinery process is introduced. It consists of four main units: a crude oil storage unit, a crude oil pretreatment unit, a distillation unit and products storage/dispatch unit. The output products from crude oil refinery process are Liquefied Petroleum Gas (LPG), Naphtha, Gasoline, Kerosene and Diesel that have a great usage in our daily life. The reason for using the Multipoint Interface/Decentralized Peripherals (MPI/DP) connection in main control loop instead of Ethernet connection is that MPI/DP speed is 185 kbps and Ethernet connection speed is 10/100 kbps, which increases the speed of transfer data through the system. Displacer level transmitters and automatic servo level gauging transmitters are used for measuring levels in the crude oil refinery process. Also differential pressure flow transmitters are used for measuring flow rate. Temperature transmitters with thermocouple temperature elements are used for temperature control. Constructing a highly stable and reliable SCADA/PLC system instead of DCS must realize automatic management and control of oil refinery process in order to avoid the waste of manpower, physical resources, and also to increase the safety of workers. 相似文献