自同步振动系统的动力学耦合特性及实验

为了研究双机驱动自同步振动系统的动力学耦合特性,引入两个激振器的平均角速度和相位差两个参数,对振动系统的参数进行无量纲化处理,得到振动系统的同步性条件和稳定性条件。定量分析了振动系统两个激振器的动力学耦合特性,发现系统的频率俘获力矩与相位差正弦值乘积的一半以阻力矩形式加在相位超前的电动机上以降低其角速度,另一半则以驱动力矩形式加在相位滞后的电动机上以增加其角速度。同步实验台振动系统的实验验证了该理论分析的正确性。     

同向回转双机驱动振动系统的自同步特性

采用了一种新的分析方法研究同向回转双机驱动振动系统的自同步特性,通过引入激振器平均角速度和相位差的两个小参数,对振动系统的参数进行无量纲化处理,提出了频率俘获力矩的概念,得到了振动系统的频率俘获方程,把同步问题转化为频率俘获方程零解的存在和稳定性问题。计算机仿真结果表明,当振动系统的参数满足频率俘获和自同步稳定运转的条件时,振动系统能很快实现频率俘获并达到稳定的自同步运转状态,验证了理论分析的正确性。     

Vibratory synchronization transmission of two exciters in a super-resonant vibrating system

In this study, vibratory synchronization transmission (VST) of two exciters is investigated in a super-resonant vibrating system to save energy. First, the frequency capture equation of two exciters (FCETE) is deduced by the average method of small parameters. The criterion of VST being the equivalent effective residual torque of motor with power supply should be smaller or equal to the frequency capture torque of the system by setting the disturbance parameters of angular velocities in FCETE to zero. The stability criterion of synchronous states is derived by complying with the generalized Lyapunov equations. Lastly, experiment and computing simulation on VST are conducted. The VST regime of two exciters is discussed in detail from coupling characteristic, current change, visual picture, phase relation, and direct verification of parameters, respectively by comparison and analyses of corresponding data. Results indicate that the key factor in VST implementation is the torque of frequency capture, which serves as the ‘vehicle’ in transferring energy. Thus, the distance between rotational centre of each exciter and mass centre of the rigid frame should be far enough to enhance the ability of VST and ensure energy saving. The theory, experiment, and computing simulation prove that the theoretical approach used in this study is useful and feasible.     

Theoretical, numerical and experimental study on synchronization of three identical exciters in a vibrating system

The theory on synchronization of two exciters is more widely used in engineering, while that of more than two exciters is less considered. So it is of great significant to investigate synchronization of three exciters. Firstly by introducing the average method of modified small parameters, the dimensionless coupling equations(DCE) of three exciters are derived, which convert the problem of synchronization into that of existence and stability of zero solutions for the DCE and lead to the construction on criterions of synchronization and stability in the simplified form for three exciters. Then the synchronization criterion is discussed numerically, as well as the abilities of synchronization and stability, some results thereof indicate that the synchronization ability increases with the increase of the coupling moment among three exciters, but decreases with that of their phase differences. Finally, an experiment on synchronization with three exciters is carried out. Through the comparison and analysis of experimental data on phase differences among three exciters, responses of system, and phases of three exciters recorded by high-speed camera, the parameters of system satisfying the above two criterions can ensure the synchronous and stable operation of three exciters. As a result, the average method of modified small parameters can be used as a theoretical apparatus studying reasonably the synchronization mechanism of three exciters, it is also proved to be useful and feasible by numeric and experiment. The present research lays the foundation and guidance for the establishment of synchronization theory system with multi-exciter and engineering design.     

On the rational dynamic modes of vibrating machines with an unbalanced vibration exciter of limited power

The aspects of choosing the design parameters of a vibrating machine made according to the scheme of a series two-mass vibrating system, as well as of the modes of its oscillations excited by two synchronously rotating unbalanced vibration exciters with a drive of limited power, are considered. The limitations on possible modes of oscillation excitation caused by taking the designed features of the vibration exciter into account are determined. At the specified masses and stiffnesses of a vibrating system, as well as for the specified parameters of oscillations of the actuating element, the rational values of the parameters of vibration exciter and the damping in the components of the vibrating system and dynamic modes, which are characterized by low expenditures of energy and a small dynamic effort transmitted to the foundation of the machine, are determined. The oscillation modes in which changing the mass of the actuating element leads to the smallest changes of the amplitudes of its oscillations are determined.     

双振动电机同步振动筛基本参数设计与调整

针对工程实际问题,以反向、变速、同步旋转的振动电机作为振动筛的激振器,通过反向同步控制电路、变频调速控制电路和准确的安装位置,可实现单轴式、双轴式和多轴式线性非共振激振器的功能。以振动电机产生的能量、无传动装置的方式直接驱动工作机体做设计要求的抛掷运动。阐述了振动电机同步振动筛的基本构成、设计原理和激振力的调整确定方式,分析计算了振动系统的振动强度、频率、振幅和输送速度等主要工作参数。与传统激振器振动筛相比,这种新型振动筛的供料输出能力和筛分效率有很大提高。     

非线性耦合同向回转的双偏心转子振动系统同步行为研究

随着振动系统逐渐朝着大型化、重型化的方向发展,大激振力振动系统是未来发展一个较热的趋势。基于这一特殊背景,提出了非线性（拉簧）耦合同向回转的双偏心转子振动系统及其同步问题。首先基于拉格朗日方程建立了系统动力学方程;随后采用运动分离法建立系统慢变参数的积分方程,推导出了系统实现同步的同步条件和稳定性准则;其次,通过数值分析研究了系统结构参数对系统同步能力及同步特性的影响;继而,采用龙格库塔法建立了非线性耦合同向回转的双偏心转子振动系统的机电耦合仿真模型,开展了系统的同步状态与系统机电耦合的动力特性的仿真分析;最后设计了相关试验装置,开展了同步试验测试。研究结果表明,系统的同步行为主要受拉簧和支撑弹簧的刚度系数、激振电机的位置参数等的影响;激振电机的相位差随着拉簧刚度系数的增加逐渐稳定在零度附近,相应地系统同步状态从反相同步逐渐变成同相同步,理论研究和试验结果能较好吻合。所有研究为研发高效节能的大型振动机械提供指导作用,同时研究成果也对振动同步领域共性问题的解决具有促进作用。     

三激振器振动系统的振动同步传动

在振动同步理论研究中,存在着一种特殊现象,无直接驱动源的激振器仍能跟随其他有源驱动的激振器进行同步运转,称之为振动同步传动。针对三机驱动水平放置的振动试验台,应用Lagrange能量方程建立动力学模型,根据线性叠加原理得到系统稳定时的响应,利用时间双尺度法获取系统的平均力矩平衡方程,并给出了系统实现振动同步和振动同步传动的同步性判据及同步状态与振动同步传动状态下的稳定性判据。在供电频率50Hz的试验条件下,测得电机2及电机3断电前后系统稳态时的激振器相位差,验证了理论推导的正确性,为振动同步传动理论在多机振动同步机械上的应用提供了依据。     

Experimental investigation into the effects of exciter motions on the primary calibration of single-ended accelerometer

It is widely known that in the primary calibration of accelerometers by using a laser interferometer, a device under test (DUT) and the laser interferometer should measure vibration at the same reference position. However, this is not applicable to single-ended accelerometers because of the limitation of their design. One way of overcoming this limitation is to measure the vibration at several positions on the exciter table surface which connects DUT to a vibration exciter. However this can present the effects of rocking motions of the exciter. Although the motions of vibration exciters are presented in several studied, the different model of exciters might have different characteristics. This paper aims to study the motions of an air-bearing exciter (model 2911) used at National Institute of Metrology (Thailand) in order to expose their characteristics, their effects on the calibration results and the measurement errors due to these effects. The motions of the exciter are shown in terms of magnitude and phase shift distributions of sensitivities. These can be obtained by measuring the magnitudes and phase shifts at several positions on the exciter surface. The effects of exciter motions are measured in terms of how much the magnitudes and phase shifts at each measured positions deviate from the average values. To illustrate these effects, parametric studies were conducted. The influences of four parameters, i.e. the angular positions of the laser points, the distance of the laser positions from the centre of the exciter surface, the number of measured positions to be averaged and the mass loading effect, were examined experimentally. The frequency of interest is between 10 Hz and 15 kHz.     

2D阀控单出杆激振缸低频特性研究

针对传统电液激振器振动频率难以提高的现状,提出了一种基于差动连接的2D阀控单出杆液压缸的新型电液激振器。阐述了激振器的工作原理,建立了数学模型并进行了仿真分析,设计了电液激振器并进行了实验研究。理论和实验结果表明:振动频率在5Hz以下工作时,激振器输出的振动波形容易出现饱和现象;随着频率的提高,饱和现象就不容易出现。激振器输出力的大小与2D阀的轴向开口成正比关系,轴向开口越大,输出的力越大。     

振动同步传动及其工业应用

利用振动可将运动和能量传给一个或多个带有偏心质量的转子,这种传动原理我们称它为振动同步传动。作同步运动的转子的转数通常与振动系统的频率相同。例如,固定于同一振动系数中的带有偏心质量的两台激振电动机,当它们获得同步运转之后,即使将其中的一台激振电动机的电源切断,只要满足一定的条件,停止供电的电机将由于系统的振动继续保持回转运动。本文提出了实现同步传动的同步性判据及同步状态的稳定性判据。同时,通过理论研究与试验,证明了这种新原理具有实用的价值。     

Control research and optimization design of self-synchronous vibrating machine

The dynamic model of a self-synchronous vibrating machine is established. Through the dynamic analysis of the self-synchronous vibrating machine with two motors, the simulation program is run based on the dynamic model of self-synchronous vibrating machine and the mathematical model of an induction motor. Simulation results show that the machine is in a poor synchronous state. The method to control the phase difference of the two eccentric rotors is then analyzed, and the self-synchronous vibrating machine is optimization designed. The simulation demonstrates that the self-synchronous vibration machine achieves speed synchronization and phase synchronization. The results verify the effectiveness of the optimization design.     

飞轮组在电涡流缓速器试验台上的应用

一些机械装置涉及飞轮的设计,它不仅能解决装置的稳定性问题,而且提供了转动惯量。文中从惯性量GD2的基本原理出发,分析缓速器试验台运动部件的转动惯量,并将它产生的转动惯量等价于实车的转动惯量。在一定范围转动惯量下对飞轮组的优化设计,最终使试验台有效地模拟不同转动惯量的汽车。     

轿车整车转动惯性测试方法与误差分析

整车转动惯量在汽车操纵稳定性、制动性和行驶平顺性等汽车性能的计算机仿真中是重要的参数 ,文中介绍了自制转动惯量试验台将轿车整车假设为刚体进行转动惯量静态测试的方法 ,并对其进行误差分析     

磁流变传动机构性能的试验研究

从流体力学的角度推导和分析了圆盘式磁流变传动机构的力矩,并以此为基础讨论了机构的动态品质、功率损耗等与机构的关系.机构传递的力矩由磁致力矩与粘性力矩构成,圆盘外径是提高传递力矩的关键尺寸;外径的增大会减少单位转动惯量所传递的力矩,增大粘性功率损失.两圆盘间隙的增大将减少粘性功率损失和单位转动惯量所传递的力矩.粘性力矩、粘性功率损失和单位转动惯量传递的力矩随磁流变液粘度的增大而增加.励磁电流与传递力矩、单位转动惯量传递的力矩等成指数关系,与功率损耗成负指数关系.     

反共振振动机械的同步性与同步传动性

对惯性式反共振振动机进行动力学建模与求解,建立反共振振动机的动力学方程和两激振电动机轴的力矩方程,推导反共振状态下的同步性判据、同步传动性判据、同步稳定性判据和同步传动稳定性判据,从理论上证明了在反共振状态下,不但能够实现振动同步,而且能够实现同步传动;同步性指数总是远大于同步传动性指数。因此只要能够实现振动同步传动就肯定能够实现振动同步。在两轴能够实现自同步的情况下,却不一定能够实现同步传动。通过试验验证了理论结果的正确性。     

Identifying the parameters of a dynamic autonomous undersea vehicle — environment system

A method for identifying some parameters of a dynamic undersea vehicle — environment system, such as a moment of inertia of rotating drive components with regard to the adjoint moments of inertia and a viscous friction factor of a propeller, is proposed. Simulation validated the high rate of convergence of the desired parameters to the true values.     

结构参数对内啮合转子压缩机受力特性的影响

在分析内啮合转子压缩机独立结构参数对转子影响的基础上,通过定义2个相对结构参数,将影响较大的3个独立结构参数关联在一起,研究了相对结构参数对工作腔压力分布、转子上承受的气体力和气体力力矩以及主轴驱动力矩的影响。研究结果表明,λe对气体力和内外转子上的气体力矩影响较大,随着λe的增大,气体力逐渐减小,内外转子上承受的气体力矩波动加剧,特别是当λe增大到一定值后,外转子上气体力矩会始终为负;λa对主轴驱动力矩影响较大,随着λa的增大,驱动力矩的平均值和变化幅度均增大。在不考虑其他因素的情况下,选择较大的λe和较小的λa对改善压缩机受力情况有利。研究结果可为内啮合转子压缩机的设计及结构参数优化提供一定的参考。     

弹性连杆的动力学建模与稳定性分析

考虑连杆弹性的曲柄滑块机构为受约束刚弹耦合机械系统，采用Kane方程，将连杆弹性变形用伽辽全法离散成空间函数和广义坐标的乘积，计及轴向缩短对连杆角速度的影响，推导出弹性连杆多自由度线性参激振动方程组。应用多尺度法并结合笛卡尔坐标变换，分析连杆第一阶弯曲模态的主参激共振，获得平凡响应稳定性临界曲线，并讨论阻尼比和惯性比等参数的影响。     

A new approach to test torque transducers under dynamic reference regimes

A system is proposed to test torque transducers under reference dynamic regimes, where the reference torque is provided by the application of angular acceleration to a coupled mass moment of inertia. The dynamic regimes include different angular velocity intervals, angular velocity steps and high torque rates. A basic general assembly is proposed and theoretical and practical analyses are performed to determine the primary parameters and depict components. The results show that the angular velocity and torque curves are repeatable and also that the simultaneous responses of torque and acceleration are linear. The mass moments of inertia involved in the measurement process are evaluated. The results provide a positive direction for future tests with transducers and the objective to fill the gap in the metrological traceability chain for torque measurement with dynamic tests and sensor verification.