Over time, the synchronous cam mechanism experiences progressive wear and tear during operation, ultimately impairing its core performance capabilities.When original design data are unavailable, disk cams are mainly maintained using curve fitting design methods. The choice of measurement points is crucial in this context. Currently, sample data is primarily collected by measuring the inner contour of disk cams for curve fitting to produce replacement cams. However, the synchronization precision at the execution end remains inadequate. To address this issue, this study introduces a method of measuring the center points of rollers to enhance accuracy. This paper develops cam error models for both surveying approaches. By integrating these with the linkage mechanism’s error model—constructed using the Modified Denavit-Hartenberg (MDH) method—an error analysis and comparison are conducted, with output-end sensitivity as the evaluation metric. This reveals the sources of errors and the pattern of error accumulation. Additionally, the synchronous segments of the cam are divided, and techniques such as constrained least squares and orthogonal basis reconstruction are employed to generate optimized cam curves. Experimental validation confirms the effectiveness of these methods. The findings indicate that synchronization errors in both schemes increase proportionally with rotational speed. Under the maximum rotational speed condition, the synchronous error at the execution end of the cam obtained using the new surveying scheme is reduced to 57.2% of that associated with the original scheme. This improvement can be mainly attributed to the fact that the new scheme mitigates the error accumulation effect arising from inner-contour-based radial data transmission and reduces the uncertainty introduced by complex nonlinear geometric mapping. This study constructs a comparative framework for independent error propagation models under two distinct surveying approaches, demonstrating how different measurement references lead to varying degrees of error accumulation at the actuator end. It elucidates the relationship between sensitivity stability and fitting precision, confirming that smooth sensitivity characteristics are essential for minimizing execution-end deviations. These findings offer novel optimization principles for reverse engineering applications. Finally, the proposed method is experimentally validated on an engineering test platform, demonstrating its applicability and potential value for industrial cam repair and remanufacturing.

High-temperature superconducting(HTS)maglev trains are subjected to random track irregularities and normal forces from onboard linear motors during operation,leading to vibrational coupling among the train bodies,maglev frames,and motors.These motor vibrations cause changes to the air gap,which in turn result in variations in the normal forces.The altered normal forces react on the motor suspension systems,affecting the vibrations of both the maglev frames and the train bodies.A dynamic model was established for HTS maglev trains equipped with an active controller.This model incorporated an additional suspension system between the motor rotor and the maglev frame to mitigate the effects of air gap variations,and introduced an active control technique to the suspension sys-tem.Under external excitations composed of random track irregularities and normal forces from the linear motor,the dynamic responses of the motor rotor were simulated using MATLAB/Simulink with both PID and Fuzzy-PID controllers.Comparisons were made with pas-sive suspension systems to verify the feasibility of the proposed control approach.Simulation results show that,compared to passive sus-pension systems,both control methods effectively suppressed air gap fluctuations in the motor,with Fuzzy-PID demonstrating signifi-cantly better control performance than PID.This approach offers a novel solution for suppressing linear motor vibrations,and its feasibili-ty has been confirmed through simulations.

In the operation, high-temperature superconducting maglev trains are susceptible to the impact of random track irregularities. These irregularities cause vibrations of the carbody and maglev frame, which are transferred to the dynamic components of the linear motor, resulting changes in the air gap. The changed electromagnetic force reacts against the motor suspension system, causing further vibrations of the maglev frame and carbody. The coupled vibrations of both components influence the safe operation of high-temperature superconducting maglev trains to some extent. To mitigate the influence of random track irregularities on the motor suspension system, a multi-rigid-body dynamic theory model was established in this study. Through simulation verification of the dynamic response under periodic excitations, the correctness of the dynamic theory model was confirmed. Furthermore, within UM software, with the linear motor normal force and random track irregularities as external excitations, a simulation of the dynamics model of the high-temperature superconducting maglev train was conducted. The influence of the vertical stiffness of the motor suspension system on the air gap of the linear motor, the vibration of the carbody and suspension frame, and the train ride comfort was studied, and the optimal value for this stiffness was determined. The results show that increasing the vertical stiffness of the linear motor suspension system to a certain extent can improve the stability of the carbody. Additionally, increasing the vertical stiffness can reduce the variation in the air gap and motor vibration to a certain extent, thus decreasing the coupling effect with the suspension frame. The results obtained in this study are based on simulation analysis under specific structural parameters and load conditions, and they can provide valuable insights for the dynamic analysis of high-temperature superconducting maglev trains.

High-temperature superconducting (HTS) pinning maglev has the potential to achieve high operational speed while having a low maintenance cost, attracting a lot of attention. The HTS pinning maglev system realizes the levitation of the vehicle through the flux pinning characteristics between the high-temperature superconducting bulk and the magnetic field of the permanent magnet guideway (PMG). Thus, the profile of the magnetic field of the PMG can significantly affect the levitation status of the vehicle, which makes the PMG irregularity become one of the main excitation sources of the system. The magnetic induction intensity on the surface of the PMG can be used to characterize the PMG irregularity, but the non-contact dynamic measurement may produce large errors by the vibration of the measurement system during the process. In order to evaluate the PMG irregularity, the vibration component needs to be separated from the overall signal. In this paper, through the synchronous measurement of the Hall sensor and accelerometer, the vibration separation method of the PMG irregularity measurement is simplified to the optimal filter estimation. The particle swarm optimization (PSO) algorithm is used to calculate the parameters of the optimal filter based on the correlation coefficient criterion. The effectiveness of the proposed method is verified by the test. The separated signal is more accurate in both time domain and frequency domain for the characterization of PMG irregularity.

Currently, the acoustical performance of hydraulic noise attenuators is usually measured in terms of insertion loss (IL) and transmission loss (TL). Compared with the TL, experimental measurements of IL appear to be easier, however, the acquisition of source and load impedance for theoretical IL seems to be time-consuming and costly. Considering that the analogy between electrical system variables and fluidic ones is complete, well-established electrical circuit representations could be used for hydraulic systems using expansion chamber configurations as the hydraulic suppressors. Utilizing the Thevenin theorem and Norton theorem in the electrical network theory, two types of pressure oscillation source representations are equivalent insofar as the suppressors are concerned and then the expression for IL could be simplified. Finally, through the experimental measurements of the IL, the most suitable electrical representation would be selected. By implementing this method, the measurements of source impedance and load impedance tend to be avoided, which appears to be an attractive approach.

High-temperature superconducting (HTS) pinning maglev has attracted attention due to its advantages of stable levitation without external energy, and integration of levitation and guidance. As one of the main excitation sources of the HTS pinning maglev system, permanent magnet guideway (PMG) irregularity is affected by the geometric and magnetism of PMG together. Therefore, the measurement method only for geometry in wheel-rail systems no longer meets the measurement requirements of PMG irregularity. In addition, the current research on HTS pinning maglev trains is mainly based on the test line, which has certain requirements for repeated measurement and measurement convenience. In this article, various sensors are set on a single Dewar HTS pinning maglev system. PMG magnetic induction intensity signal, the vibration response signal, and the geometric signal are measured, respectively. The equidistant track marker on the PMG surface is used as a keyphasor pulse signal to realize the spatial resample method. After converting the time-domain signal to the spatial domain, the PMG local irregularity evaluation is carried out. Based on the seven-parameter fitting model, the PMG irregularity spectrum is fit. Taking the Chinese mainline railway track spectrum as the contrast, it can be concluded that the mid-wave irregularity of the HTS pinning maglev system is higher. The research content of this article provides a theoretical basis for the selection of measurement methods under different measurement requirements and conditions. The obtained irregularity power spectrum can provide a reference for the dynamic simulation of HTS pinning maglev.

为完成移动机器人对列车风管的摘解任务,需要对列车风管管接头进行定位.针对列车风管管接头不易识别且识别定位需要一定实时性和精度的问题,利用双目视觉系统提出了一种间接识别定位方法.在目标识别中,根据列车风管的特点,基于颜色特征在HSV空间中对风管近端金属圈进行识别,提取出金属圈形心坐标;在三维重建中,利用具备较高精度和一定实时性的组合立体匹配算法对风管近端金属圈进行三维重建,得到其三维坐标后根据管接头与近端金属圈相对位置关系固定的特点,通过空间坐标转换得到管接头的三维坐标,实现列车风管管接头的定位.最后,在(200～650)mm的距离范围内进行实验验证,实验最大绝对误差为12.88mm,算法最长耗时为245ms,结果表明该方法满足要求.

Inspired by the guidance principle in the electromagnetic levitation system, a new permanent magnet electrodynamic suspension (PM EDS) structure with ferromagnetic guidance track is proposed and analyzed in this paper. Considering the lack of effective guidance ability for the PM EDS system, we adopted the ferromagnetic guidance track as being mounted under the conductor plate. The guidance principle is studied and the implementation of the guidance function is also introduced, and the finite element method (FEM) is employed and its accuracy is confirmed via the PM EDS high-speed rotating experimental platform fabricated in our laboratory. The influence of longitudinal speed on the guidance force is taken into account, which shows that the guidance performance is enhanced more obviously at low speeds. Moreover, the influence of the guidance track parameters on the guidance performance is also analyzed, including the geometric parameters, section shape, installation position and material. The equivalent small-scale PM EDS system experimental prototype is carried out to validate the effectiveness of the ferromagnetic guidance. The proposed ferromagnetic guidance structure is demonstrated to improve the guidance performance of the PM EDS system effectively, which will offer a technical reference for the practical engineering application of the PM EDS system.

人体躯干能够根据负载重量而自适应调节前倾角度,有利于人体对下肢外骨骼的控制和人机系统行走稳定性.当超出一定负重时,躯干前倾困难.设计一种新型髋背结构,利用负重重量增加躯干前倾角度.首先分析人体步态,方便仿真时施加约束和驱动等元素;然后将人体简化为七杆模型,用Kane方法建立动力学方程,减少中间变量,提高计算效率;最后通过Adams进行动力学仿真验证.仿真得到的结果表明:承载负重之后,髋背机构能使人体躯干前倾更加省力,人机系统重心位置相比于之前接近稳定区域,并且系统重心比之前有所降低,进一步保证系统稳定.

为解决在列车底部直线移动的机器人对风管进行识别定位摘解时需到达两节车厢之间的自定位问题,提出一种基于单目视觉里程计的自定位方法.该方法根据单目相机在列车底部竖直向上拍摄时图像颜色较深,而当相机将要到达两节车厢之间时所拍摄图像中会有明显亮度变化区域的特点,选取关键帧图像,通过图像处理提取出图像中目标区域信息,根据所提出的运动估计算法估计相机自身的运动.最后,通过实验计算得到该方法的绝对误差为0.059 s,相对误差为1.16％,验证了该方法的可行性.

为应对传统液压电磁换向阀不能长期供电和油液对温升敏感等工况,以三位四通液压换向阀为载体设计一种新型三稳态电磁换向机构,机构快速换向性使得阀口迅速关闭导致管路产生液压冲击,故引入磁流变阻尼技术,将"剪切-阀"式磁流变阻尼装置沿阀芯轴线串联,通过控制阀口关闭速率以缓解液压冲击对系统的不良影响.仿真结果表明:主动控制阻尼的换向过程随着阻尼力的增大而放缓,管路液压冲击峰值随之减小且振荡时间随之缩短,但由于换向时间较短,变阻尼装置响应能力有限,不建议其采用闭环控制.

针对目前声屏障人工巡检存在的效率低、难度大等问题,提出了一种新型声屏障巡检机器人结构.对巡检机器人结构的静力学分析,得到巡检机器人满足结构设计要求.对巡检机器人进行动力学分析,得到驱动的基本条件,验证了越障的可行性,结果表明,该巡检机器人有两组行进装置,交替越障可以实现翻越声屏障立柱而连续行进.通过控制气缸的伸缩,可以改变关节杆串联后的状态,来适应声屏障的不同形状.机器大越障前进性能好,能达到预定的巡检设计要求.

以双线圈内绕型剪切阀式磁流变阻尼器为研究对象,根据其磁场自封闭性,采用磁路法建立磁路数学模型.通过关键结构参数进行定性分析,得到活塞台阶间隙处磁感应强度近似化的结构优化依据.利用Ansoft Maxwell有限元仿真软件进行验证,结果表明:对于双线圈甚至多级线圈的内绕型剪切阀式磁流变阻尼器,采用磁路法进行初期设计计算有效且精确.

建立管片式换热器的三维物理模型,利用计算流体力学和FLUENT分析了不同结构尺寸参数的散热片,得到管片式散热器空气侧的流场分布与传热特性.为进一步分析管片式散热器散热片的性能,分析了不同雷诺数Re、散热片的节距、厚度等参数对散热器的对流换热系数和压降的影响,得到了不同结构散热片的传热因子j和阻力因子f,并引入无量纲参数j f 13来评价传热性能.优化结果表明:散热片厚度为0.2mm,节距为2.22mm时,管片式换热器综合性能最优.

在断路器弹簧操动机构中凸轮的使用使得操动机构的输出力特性能够与断路器的负载特性更好地配合.凸轮轮廓曲线的合理设计也直接影响着弹簧操动机构的输出力特性.弹簧操动机构中对凸轮轮廓曲线准确并且方便的设计方法具有重要意义.通过对凸轮参数与输出力特性的关系分析,结合摆动从动件滚子凸轮的设计方法建立了弹簧操动机构中凸轮机构设计的数学模型.基于MATLAB利用遗传算法开发了图形用户界面(GUI),弹簧操动机构中凸轮参数化设计直观方便.

Due to the strong magnetic force between segments of the permanent magnet guideway (PMG), the unmovable electromagnetic turnout becomes one of the most possible choices for high-temperature superconducting (HTS) maglev systems. Meanwhile, it has advantages of quicker response and smaller volume compared with mechanical turnout. A complete turnout system is vital for further evaluating feasibility. Based on the previous studies in ASCLab of Southwest Jiaotong University, a complete electromagnetic turnout prototype system is introduced in this article, which consists of two electromagnets, a Halbach type PMG, a control system, and a maglev vehicle model with a single-domain YBaCuO cylindrical bulk superconductor. In order to guarantee the stable running of vehicle at the turnout area, electromagnets are necessary to provide a similar magnetic field compared with the normal Halbach PMG. Based on the system, the measurement on the magnetic field was done and indicates that the electromagnet could replace permanent magnets of guideway to create a similar magnetic field distribution. The magnetic field experiment on this prototype system further certifies the applicability of the Halbach electromagnetic turnout. For future HTS maglev transportation, the electromagnetic turnout could be widely used in low-speed application such as railway station, switchyard, and laboratory.

为提高液压外骨骼机器人油箱的换热性能,采用CFD数值模拟方法,对不同翅片结构的圆环形槽翅片油箱流动传热性能进行了三维数值模拟,得到了不同入口风速下翅片表面平均换热系数、进出口压降和综合评价系数JF因子随翅片结构变化的特性曲线.研究结果表明:翅片厚度在0.5～0.9 mm时,换热系数随翅片厚度的增加而减小,同时压降随厚度的增加而增大;翅片间距在2.1～2.9 mm时,换热系数随翅片间距的增大而增大,同时压降随间距的增大而减小;翅片高度在10.5～14.5 mm时,换热系数和压降都随翅片高度的增加而增大.研究结果表明:当翅片厚度为0.5 mm,翅片间距为2.9 mm,翅片高度为12.5 mm时,翅片单元整体综合换热性能最优,仿真结果为翅片油箱结构优化设计提供了参考.

为了能够精确控制艾灸点皮肤温度,提高艾灸效果,设计并实现了一个稳定高效的温度控制系统.该系统采用STM32F103单片机、TN901热电堆红外传感器和42BYGH604A步进电机,通过42BYGH604A步进电机驱动滚珠丝杠进而带动燃烧的艾条相对于艾灸点做前后运动,来调整艾灸点皮肤的温度.通过自整定模糊PID算法实现对艾灸点皮肤温度的稳定控制.实验结果表明,系统超调量为0.73℃;稳态温度保持在41士0.07℃以内.与常规的PID控制系统相比,基于自整定模糊PID算法的艾灸点皮肤温度控制系统具有更高的稳态精度.

针对下肢外骨骼机器人在使用过程中,负重重心在矢状面垂直方向上的轨迹波动造成的能量消耗和冲击等问题,在常规双驱动单元外骨骼的髋部和背部设计了一种新型的连杆绳轮机构.该机构使外骨骼所承载的负重在人体重心在矢状面内做波浪形轨迹运动时与之做方向相反的运动,减小负重重心的轨迹波动,增加人体负重行走时的稳定性.在分析人体重心在行走状态下矢状面内的运动轨迹的基础上,确定了新机构的结构方案和尺寸.运用Denavit-Hartenberg方法和连杆设计理论求解出外骨骼在装备和未装备髋背机构时负重的重心轨迹,最后通过ADAMS的运动仿真进行验证,结果表明:这种髋背机构可明显降低负重重心的轨迹波动.

为了研究平面波截止频带内,进、出口偏置型扩张室压力脉动衰减器结构参数对其一维解析法计算精度的影响,基于面积突变处高阶模态的耗散效应,对两类偏置型扩张室一维解析法的有效性进行了分析.首先,截止频率范围内双调谐内插管扩张室一维解析法的计算结果与实验测量结果吻合良好,证明了该方法应用于液压脉动衰减器是可行的;其次,将广泛应用于气体消声系统的两类进、出口偏置型扩张室结构(结构1和结构2)引入液压系统,制成相应的压力脉动衰减器,并利用一维解析法和三维有限元法分别得到其理论计算值;最后,以扩张室腔室内部存在局部非平面波效应为背景,研究了内插管插入深度、偏心距以及偏转角对一维解析法有效性的影响.研究结果表明:结构1、2偏心距为40 mm、偏转角180°时,进、出口内插管插入深度对5000 Hz频带内(截止频率5 469 Hz)高频区域的传递损失影响较大;而当结构1、2的内插管插入深度选定时,偏心距以及偏转角对0～4 000 Hz一维解析法计算精度的影响可忽略不计,而在4000～5000 Hz研究频带内,这种影响则不可忽略.