跳跃式移动机构的移动机理及实验研究

介绍了一种新型跳跃式移动机构,阐述了该机构的移动机理及其控制方法.跳跃式移动机构采用小型振动电机作为驱动,利用电机内偏心轮的旋转所产生的周期性的向心力及与工作表面的间歇性摩擦力的共同作用,实现机构的跳跃移动,两个不同放置位置的电机的组合运用,可实现机构可调速的直线运动和回转运动,通过一系列实验.验证了跳跃式移动机构可实现二维平面内的自由移动.     

微型直流电机检测系统的设计与实现

随着现代汽车的不断发展,汽车上大量使用了微型直流电机来驱动天窗、控制风门。车用直流电机结构特殊．在实际应用中对带负载情况下的相电流、运转角度与反馈电压的线性度等问题具有严格要求。通过硬件电路的设计、软件代码的编写实现了直流电机综合性能测试系统,该系统结构简单、性能稳定,能够满足企业对微型直流电机自动化检测的需求。系统运用磁粉制动器、扭矩传感器来模拟负载的加载和检测,此方法能够应用到其他需要模拟负载的系统中,具有良好的推广应用价值。     

Design of a slider-crank leg mechanism for mobile hopping robotic platforms

Legged locomotion has been widely researched due to its effectiveness in overcoming uneven terrains. Due to previous efforts there has been much progress in achieving dynamic gait stability and as the next step, mimicking the high speed and efficiency observed in animals has become a research interest. The main barrier in developing such a robotic platform is the limitation in the power efficiency of the actuator: the use of pneumatic actuators produce sufficient power but are heavy and big; electronic motors can be compact but are disadvantageous in producing sudden impact from stall which is required for high speed legged locomotion. As a new attempt in this paper we suggest a new leg design for a mobile robot which uses the slider-crank mechanism to convert the continuous motor rotation into piston motion which is used to impact the ground. We believe this new mechanism will have advantage over conventional leg mechanism designs using electronic motors since it uses the continuous motion of the motor instead of sudden rotation movements from stall state which is not ideal to draw out maximum working condition from an electronic motor. In order to control impact timing from the periodic motion of the piston a mechanical passive clutch trigger mechanism was developed. Dynamic analysis was performed to determine the optimal position for the mechanical switch position of the clutch trigger mechanism, and the results were verified through simulation and experiment. Development of a legged locomotion with two degrees of freedom, slider-crank mechanism for impact and additional actuation for swing motion, is proposed for future work.     

基于DSP的新型电参数测量仪设计

针对电机型式试验中的电参数测试,设计了一种基于DSP的新型电参数测量仪。详细论述了整个系统的硬件构架与软件算法,该系统通过采用高精度A/D转换器、DSP芯片以及上位机来完成电压、电流、功率、功率因数及频率的测量与数据的输出显示。对于中小型电机,测量仪既可测三相交流电参数,又可同时测量单相交流与直流电参数;当被测对象为直流有刷电机时,还能测量其转速;测试量程根据输入电流、电压的大小自动进行切换。测试结果表明该系统精度高,运行稳定可靠,能够满足实际需求。     

Operational mode-shape normalisation with a structural modification for small and light structures

When dealing with small and light structures, difficulties occur when measuring the modal parameters. The resonant frequencies are usually relatively high and therefore a wide frequency range is needed for the measurement. Furthermore, the mass that is added to the structure by the sensors causes structural modifications. To overcome these difficulties, an improved method using an operational modal analysis instead of an experimental modal analysis is proposed in this study. It is derived from the sensitivity-based operational mode-shape normalisation with a consideration of the mode-shape variation. The measurement of the excitation force is not needed, because the operational modal analysis is used and only two simultaneous response measurements at an unknown excitation are required. The proposed method includes the cancellation of the added mass, resulting in mode shapes and resonant frequencies of the unmodified structure. The numerical and experimental results on small and light structures are compared with the results of the experimental modal analysis. The comparison shows that the proposed approach allows measurements over a wide frequency range and increases the accuracy of the results compared to the sensitivity-based operational mode-shape normalisation and also compared to the particular experimental modal analysis method that was used in this study. The advantages of the proposed method can be seen whenever the mass that is added to the structure by the accelerometer is not negligible and therefore a variation of the mode shapes occurs.     

Driving and braking control of PM synchronous motor based on low-resolution hall sensor for battery electric vehicle

Resolvers are normally employed for rotor positioning in motors for electric vehicles,but resolvers are expensive and vulnerable to vibrations.Hall sensors have the advantages of low cost and high reliability,but the positioning accuracy is low.Motors with Hall sensors are typically controlled by six-step commutation algorithm,which brings high torque ripple.This paper studies the high-performance driving and braking control of the in-wheel permanent magnetic synchronous motor(PMSM) based on low-resolution Hall sensors.Field oriented control(FOC) based on Hall-effect sensors is developed to reduce the torque ripple.The positioning accuracy of the Hall sensors is improved by interpolation between two consecutive Hall signals using the estimated motor speed.The position error from the misalignment of the Hall sensors is compensated by the precise calibration of Hall transition timing.The braking control algorithms based on six-step commutation and FOC are studied.Two variants of the six-step commutation braking control,namely,half-bridge commutation and full-bridge commutation,are discussed and compared,which shows that the full-bridge commutation could better explore the potential of the back electro-motive forces(EMF),thus can deliver higher efficiency and smaller current ripple.The FOC braking is analyzed with the phasor diagrams.At a given motor speed,the motor turns from the regenerative braking mode into the plug braking mode if the braking torque exceeds a certain limit,which is proportional to the motor speed.Tests in the dynamometer show that a smooth control could be realized by FOC driving control and the highest efficiency and the smallest current ripple could be achieved by FOC braking control,compared to six-step commutation braking control.Therefore,FOC braking is selected as the braking control algorithm for electric vehicles.The proposed research ensures a good motor control performance while maintaining low cost and high reliability.     

Investigation of the physical mechanisms in rolling bearings during the passage of electric current

With the increasing use of frequency converters as control units for electric motors, bearing failures caused by the passage of electric current through the bearings are more common. This paper discusses the most relevant parasitic current loops in frequency converter‐driven motors that can lead to damage of bearing raceways or deterioration of lubricants. Electrical stray capacitances, which are inevitably present in any electric motor, in combination with the high‐frequency components of the drive voltages, have been identified as the source of electric discharge machining (EDM) currents. Based on an EDM equivalent electric circuit, the passage of electric current through the rolling contact of a bearing is simulated. A set‐up is introduced to initiate EDM processes in bearings under well‐controlled electrical and mechanical conditions. The effect of EDM currents on bearing elements in the presence of different lubricants is studied. Initial results are presented.     

旋转行波超声电机性能提升技术进展

为推动旋转行波超声电机的发展及其在精密驱动领域的应用,综述了其性能提升技术研究进展并分析了现阶段尚且存在的技术问题。首先,从定子行波的合成、质点椭圆运动轨迹、接触界面的摩擦驱动等方面论述了传统旋转行波超声电机的运行机理。然后,从结构优化和新材料应用角度综述了旋转行波超声电机的发展及其局限性;从温升控制角度阐释了温度变化对超声电机性能的影响并介绍了现有解决方案;论述了变预压力对谐振频率漂移的耦合影响,并指出了目前研究存在的不足;从双行波驱动角度分析了超声电机发展过程中的重大突破,概况了其研究历程及可行的发展方向。最后,归纳了旋转行波超声电机亟待解决的技术难题,并建议了解决方案。     

基于形状记忆合金的微小型光热驱动马达

在分析了形状记忆合金双程记忆效应原理的基础上,采用铜锌铝双向记忆合金片,设计并加工制作了两种微小型光热驱动马达,对其进行了驱动实验研究.研究结果表明,用输出波长为1064nm的YAG脉冲激光作为光热驱动马达的驱动源,在适当的输出功率和频率下,棘轮棘爪型光热驱动马达可获得较精确的步距,齿轮传动型光热驱动马达可获得较高的转...     

数字称重式全自动包装机

介绍了一种新型全自动包装机的设计。该设计采用三台步进电机分别实现落料、制袋、切断的独立动作。为了准确控制步进电机的运动 ,加入了自动检测和控制电路     

旋转型压电行波超声马达的驱动与控制技术

压电行波超声马达是一种由高科技发展起来的全新概念产品，它利用压电陶瓷的逆压电效应和超声振动，将定子的微观变形通过共振放大和界面摩擦，转换成转子的宏观运动。     

具有止动点的步进电机控制设计

通常对步进电机的驱动控制是采用开环控制的,但是当步进电机工作在具有运行的止动点时,步进电机就需要根据当前的状态自动调节自身的运行速度。为了实现对具有止动点步进电机的自动控制,采用了一种通过角度反馈实现步进电机控制的方法,可以使步进电机自动寻找最小最大止动点,并且可以在运行接近止动点时实现缓慢可靠的停止。     

电涡流传感器的脉冲激励与双参数检测

采用矩形脉冲作为激励信号,对电涡流传感器在位移检测过程中谐振频率及谐振阻尼的变化情况进行了研究分析.建立了以现场可编程门阵列(FPGA)为核心芯片的检测系统,用于产生所需要的矩形脉冲激励信号以及对传感器响应信号的欠采样.利用8 mm直径的电涡流线圈,对0～10 mm范围内碳钢目标靶的位移响应特性进行了测量,借助短时傅里叶变换分析了响应信号中频率成分的分布情况,同时获得了谐振频率及谐振阻尼的测量值.验证了通过脉冲激励同时获取电涡流传感器双参数检测的可行性.为研制基于电涡流效应的位移传感器及无损探伤传感器提供了一种新思路.     

轿车电动座盆振动测试系统研究

提出基于加速度传感器的轿车电动座盆的振动测试系统方案,座盆在设备上夹紧后,采用大功率直流电源通过接触器给座盆电机供电,用PLC控制接触器的通断和电机的供电电流方向,使座盆能够在水平、垂直、仰角三个方向上进行正反转,在座盆运动前将加速度传感器紧贴与座盆滑轨下方正中位置.在座盆运动过程中采集加速度传感器的信号,并用LabVIEW编程软件对信号进行处理,从而获得滑轨振动的峭度、峰值、峰峰值、均方根幅值等参数,将这些参数与要求的合格范围进行比较判断合格与否.实验研究表明:系统的振动动态检测范围0-120dB,分辨率为0.0005g,并可以长期稳定运行.     

Application to induction motor faults diagnosis of the amplitude recovery method combined with FFT

This paper presents a signal processing method – amplitude recovery method (abbreviated to ARM) – that can be used as the signal pre-processing for fast Fourier transform (FFT) in order to analyze the spectrum of the other-order harmonics rather than the fundamental frequency in stator currents and diagnose subtle faults in induction motors. In this situation, the ARM functions as a filter that can filter out the component of the fundamental frequency from three phases of stator currents of the induction motor. The filtering result of the ARM can be provided to FFT to do further spectrum analysis. In this way, the amplitudes of other-order frequencies can be extracted and analyzed independently.If the FFT is used without the ARM pre-processing and the components of other-order frequencies, compared to the fundamental frequency, are fainter, the amplitudes of other-order frequencies are not able easily to extract out from stator currents. The reason is when the FFT is used direct to analyze the original signal, all the frequencies in the spectrum analysis of original stator current signal have the same weight. The ARM is capable of separating the other-order part in stator currents from the fundamental-order part.Compared to the existent digital filters, the ARM has the benefits, including its stop-band narrow enough just to stop the fundamental frequency, its simple operations of algebra and trigonometry without any integration, and its deduction direct from mathematics equations without any artificial adjustment.The ARM can be also used by itself as a coarse-grained diagnosis of faults in induction motors when they are working.These features can be applied to monitor and diagnose the subtle faults in induction motors to guard them from some damages when they are in operation. The diagnosis application of ARM combined with FFT is also displayed in this paper with the experimented induction motor. The test results verify the rationality and feasibility of the ARM.It should be clarified that the ARM must be applied in three phases of currents in electrical machines. For a single phase of alternating current or direct current, it can do nothing. However, since three-phase electrical machines have a dominant position in the application field in modern economic society and it is natural and convenient to acquire three phases of stator currents during the three-phase electrical machines are tested, it is necessary and meaningful to develop the ARM to diagnose and guard them.     

轮毂电机独立驱动电动汽车动力减振机构设计与研究

采用轮毂电机多轮驱动是电动汽车发展的新方向。它不仅具有简化传动系统结构、减轻整车质量和降低地板高度的优点,而且便于提高传动效率,实现复杂的底盘控制。然而,轮毂电机的引入增加了非簧载质量,不利于电动汽车的行驶平顺性。为此,本文在分析传统集中电机驱动布置与轮毂电机独立驱动布置两类电动汽车系统垂向振动的基础上,提出新型的轮毂电机布置形式与相应的动力减振机构,并以非簧载质量的垂向振动量最小为目标函数,以动力减振机构的弹簧刚度和阻尼参数为设计变量,进行了优化设计,减小了电动汽车行驶过程中的垂向振动,提高了汽车行驶平顺性。此方法可为轮毂电机的设计及布置型式提供借鉴。     

稀土永磁电机在起重机行业的应用研究

总结了稀土永磁电机的主要优缺点,对比直流电机、异步电机与其的主要性能差异,分析了起重机起升机构与运行机构中驱动装置的应用现状,阐述了稀土永磁电机在起重机行业的应用前景及优势,并提出存在的问题。     

小型非晶三相感应电机铁芯的性能

以常见的小型三相异步电机为研究对象,建立了三相异步电机模型,并用铁基非晶材料和硅钢材料分别制作了异步电机的定子铁芯,研究了非晶铁芯与硅钢铁芯的性能和特点。采用软磁交流测试系统对两种材料制成的铁芯进行了交流损耗和矫顽力的测试,测试结果显示:在相同的频率和磁感应强度下,非晶铁芯损耗仅为传统硅钢铁芯损耗的1/3左右,而其剩磁仅为传统铁芯剩磁的1/4,表明非晶铁芯的损耗和矫顽力远小于硅钢铁芯的损耗和矫顽力,且工作频率越高,二者数据差别越大,说明非晶材料较硅钢材料具有更优异的软磁性。建立了三相异步电机的有限元分析模型,对非晶合金铁芯电机和传统硅钢铁芯电机进行了有限元求解。结果显示,采用非晶定子铁芯的电机比传统采用硅钢定子铁芯的电机更加高效节能。该研究成果为深入开展铁基非晶材料在异步电机中的应用提供了参考。     

跳跃机器人的研究现状与发展趋势

由于受到动物和人类的跳跃运动的敏捷性的启发,在过去的几十年间,越来越多的国内外研究者开始研究跳跃运动并着手开发了各种各样的跳跃机器人。跳跃运动是一种高度非线性的并且由交替的飞行和着地阶段组成的动态运动,这给跳跃机器人的控制提出了很大的挑战。综述了国内外跳跃机器人的研究现状,对现有的跳跃机器人进行了分类,对跳跃机器人的驱动方式、动力学模型的建立和控制方法等方面进行了详细分析,提出了目前跳跃机器人研究的关键技术,最后指出了跳跃机器人的发展趋势。     

拟“向日葵”感光式智能窗帘系统设计

本设计是基于STC89C52RC单片机的智能窗帘控制系统。设计主要通过光传感器,感应太阳光强度的变化,进而控制步进电动机运行来调节窗帘的开合角度。系统同时具有声控、红外遥控等功能,使感光式窗帘控制系统具有丰富的智能化功能,更加人性化,具有一定的推广应用价值。