Integral sliding mode control for flexible ball screw drives with matched and mismatched uncertainties and disturbances

The design of servo controllers for flexible ball screw drives with matched and mismatched disturbances and uncertainties is focused to improve the tracking performance and bandwidth of ball screw drives.A two degrees of freedom mass model is established based on the axial vibration characteristics of the transport ball screw,and the controller of an adaptive integral sliding mode is proposed combining the optimal design of state feedback gain matrix K to restrain the vibration and the matched disturbances and uncertainties.Then for the counteraction of the mismatched disturbances and uncertainties,a nonlinear disturbance observer is also developed.The trajectory tracking performance experiments and bandwidth analysis were conducted on experimental setup with the proposed control method.It is proved that the adaptive integral sliding mode controller has a high tracking performance and bandwidth especially for the axial vibration characteristics model of ball screw drives.And the ball screw tracking accuracy also has a considerable improvement with the application of the proposed nonlinear disturbance observer.

Roller Screw and Threaded Chain Speed Reducer: An Experimental Evaluation

We are developing a speed reducer that can be considered a transformation of a worm gear reducer: the worm is replaced by an inverted roller screw, and the gear is replaced by a threaded chain drive. This configuration lessens wear, increases load capacity, and improves efficiency. The threaded chain consists of nut-shaped links. This paper presents the results of tests carried out on a prototype with a reduction ratio of 46.

Axiomatic design method to design a screw drive in-pipe robot passing through varied curved pipes

A screw drive in-pipe robot is promising inspection equipment for small pipes. However, most of the existing screw drive in-pipe robots have problems of motion interference and slipping inside curved or irregular pipes. These problems result from the coupled relations among the steering motion, the motion speed and the load ability of the robot. In order to deal with the problems, the axiomatic design （AD） theory is applied to evaluate and analyze the existing designs. Then an uncoupled con- cept design based on the AD theory is proposed and the complete AD decomposition process is presented. After that, the pro- posed robot based on a tri-axial differential angle modulation mechanism is designed to realize the uncoupled concept. Finally, the uncoupled property is verified in a dynamics simulation system. The simulation results indicate that the mc tion speed, load ability and steering motion of the proposed robot can be adjusted individually compared with the robots taat have inclin- ing-angle-fixed rollers. Owing to the uncoupled design, the proposed robot can mechanically adapt to straight pipes and curved pipes with less roller slipping.

Reasonable Drive Selecting of Parallel Mechanisms Based on Screw Theory

By rigidizing the input joints, all possible combinations of drive selecting for the 4-PPPS parallel mechanism are analyzed based on the screw theory in this paper, and the five of them are proved to be reasonable. Then choosing the one as mechanical actuators, the workspace of the 4-PPPS parallel mechanism is deduced according to the rational input scheme. Finally the rationality of input scheme for this mechanism is identified on the basis of the continuity of the workspace.

基于改进Deeplabv3+算法的滚珠丝杠驱动表面点蚀缺陷检测

针对滚珠丝杠驱动表面背景环境复杂、点蚀缺陷目标小因而难以检测的问题,提出改进的Deeplabv3+滚珠丝杠驱动表面缺陷分割算法。本算法采用Re2Net-50替换Deeplabv3+的主干网络,显著提升了对小尺寸缺陷目标的识别能力。此外,通过在主干网络中融合特征金字塔网络FPN,能够加强多尺度信息的提取,从而增强了对缺陷目标的精确定位。最后,本研究在Deeplabv3+网络的ASPP模块之后引入了Coordinate Attention机制,能够增强模型对图像中空间和维度的关注,有效地捕获了图像中的长距离空间依赖关系。实验结果表明,与原始的Deeplabv3+相比,所提算法在平均交并比MIoU指标上提高了4.38%,准确率Accuracy提高了5.52%,F1-score提高了2.74%。同时,与其他经典的语义分割算法相比,所提算法也展现出了一定的优越性。

CNC机床丝杠热误差实时补偿设计及自动补偿试验

为了降低数控机床丝杠传动系统因热误差引起的定位误差,完成机床工作台各运行阶段的实时补偿。用非接触模式为丝杠非电机连接端安装位移检测器,以电涡流传感器时间监测丝杠端面位置数据,获得丝杠产生的总热误差,通过热补偿得到每段丝杠的热误差程度,确定每段坐标系原点发生的偏移,完成自主补偿机床丝杠热误差的效果。研究结果表明:采用分段补偿方法可以获得比其他热误差补偿模型更优的丝杠全段补偿性能。分别检测丝杠各段发生的热误差再对其实施补偿,可以根据丝杠各部位热误差程度实施补偿。

Three-dimensional Modeling for Predicting the Vibration Modes of Twin Ball Screw Driving Table

As a redundant drive mechanism, twin ball screw feed system has the advantage of high stiffness and little yaw vibration in the feeding process, while leads to increased difficulty with vibration characteristics analysis and structure optimization. Only low-dimensional structure and dynamics parameters are considered in the existing research, the complete and effective model for predicting the table＇s vibrations is lacked. A three-dimensional（3D） mechanical model of twin ball screw driving table is proposed. In order to predict the vibration modes of the table quantitatively, an analytical formulation following a comprehensive approach is developed, where the drive system is modeled as a lumped mass-spring system, and the Lagrangian method is used to obtain the table＇s independent and coupled axial, yaw, and pitch vibration modes. The frequency variation of each mode is studied for different heights of the center of gravity, nut positions and table masses by numerical simulations. Modal experiment is carried out on the Z-axis feed table of the horizontal machining center MCH63. The results show that for each mode, the error between the estimated and the measured frequencies is less than 13%. The independent and coupled vibration modes are in accordance with the experimental results, respectively The proposed work can serve a better understanding of the table＇s dynamics and be beneficial for optimizing the structure parameters of twin ball screw drive system in the design stage.

螺旋驱动可变径管道机器人设计与实验研究

针对目前管道清洗机器人存在的通过性差、结构复杂、适应范围单一的问题,设计一款基于螺旋驱动原理的具有自适应变径的轮式气动管道清洁机器人。该机器人由前部螺旋行走机构、清洗机构、中间动力输送机构、后部支撑行走机构组成,可适应360~440 mm的管道。简述该机器人的整体结构和工作原理;通过建立机器人简化模型,分析机器人在弯管内的通过性;对机器人在垂直管道内的平衡状态进行静力学分析,得到支撑气缸与气动马达的选型参数;通过ADAMS软件模拟机器人运动状态,对机器人在管道内位移轨迹和接触力进行分析,仿真结果表明机器人可顺利通过弯管;最后通过样机试制并进行了行走实验,验证了机器人结构设计的可行性和合理性。

下肢康复外骨骼机器人结构设计与动力学仿真

针对下肢运动障碍患者的康复训练,设计了一款具有新型结构的八自由度下肢康复外骨骼机器人,利用滚珠丝杠驱动小腿代替传统直流电机驱动方式,实现膝关节的伸展/屈曲运动。首先用SolidWorks设计建立外骨骼机器人模型,并用Abaqus对模型中关键零件进行校核,然后针对外骨骼机器人的结构建立简化模型,并通过建立拉格朗日方程进行动力学分析。最后,为探究外骨骼机器人各关节活动所需驱动力和力矩大小与关节运动角度的规律,把外骨骼机器人模型数据导入Adams中,进行了外骨骼机器人平地行走的动力学仿真,得到了模型各关节的运动规律和驱动关节活动所需力矩与力的大小,为后续电机选型提供了参考。仿真结果显示:所设计的外骨骼机器人可以完成平地行走任务,运动时关节角度变化平稳,由此验证了外骨骼机器人的合理性。

压水堆控制棒驱动机构传动部件磨损研究现状

在压水堆核电站中,控制棒驱动机构(CRDM)是实现反应堆启动、调节功率、保持功率、正常停堆和事故状态下的紧急停堆的关键设备,其可靠性直接关系到核电站的运行安全,磨损是该机构失效的主要形式。压水堆CRDM所用传动部件主要有磁力提升钩爪式和丝杠滚珠式,磨损失效是传动部件主要的失效形式。目前针对CRDM传动部件磨损的研究进展缺乏系统地分析或综述。本文介绍了CRDM传动机构的结构和运动形式,阐述了CRDM传动机构的材料选型与未来研究方向,并概述了核电行业中的CRDM传动机构的磨损研究进展,最后讨论了两种机构基于不同理论的磨损预测模型,并对CRDM传动机构材料的未来研究方向进行展望。

基于ABAQUS的变口径变高度连卷袋支架设计分析

通过对铰链机构、螺纹传动机构、动力传动系统等关键零部件进行设计,实现变口径变高度连卷袋支架设计。利用SolidWorks进行计算机辅助设计,得到支架的装配特征。利用ABAQUS有限元软件对从动齿轮进行自由模态和约束模态分析,获得从动齿轮各阶固有频率和振型,得出从动齿轮在转动时可以有效避开共振区,不会产生共振现象。

螺旋结构参数对螺旋推进车行驶性能的影响

为优化螺旋推进车结构设计,基于多体动力学和离散单元法对车辆行驶过程进行协同仿真,通过改变螺旋结构参数,包括螺旋角和螺旋线数,研究其对车辆行驶性能的影响程度。仿真结果表明:在不同驱动速度和转速下,综合考虑螺旋角为30°时车辆具有更好的行驶情况和驱动性能;螺旋线数量从1线增加为2线时,车辆滑转率明显降低,偏航角减小,行驶过程更平稳。研究结果可为螺旋推进车的进一步研究提供参考。

煤层气井排采设备适应性分析

排采设备的选择是否合理是保障煤层气井连续、稳定、合理排采的前提条件。煤层气井井型种类多,部分井轨迹复杂,采用的主要排采设备有杆式抽油泵、管式抽油泵、顶驱螺杆泵、电潜螺杆泵、水力同心型无杆泵等多种。根据不同排采设备不同的排采原理,以及它们的优缺点和适用条件,对它们在潘庄区块不同条件的煤层气井的应用情况,从检泵周期、检泵原因以及防偏磨、防煤粉、能否满足沉没度要求等多角度进行了适应性分析,总结出了考虑地面、井筒、储层、费用等多因素条件下各排采设备对煤层气井的适用条件,为潘庄区块及类似煤层气井排采设备的优选提供了重要的参考价值。

基于DSP的永磁同步抽油机开发

针对开发后期油井面临长冲程、低冲次的开采要求,传统抽油设施需要配套使用减速机,导致传动效率低下,难以达到高效开采目标。鉴于永磁同步电机在交流伺服控制领域的广泛应用及其不断提升的控制性能指标,深入研究其控制技术显得尤为重要。重点研究基于数字信号处理器(DSP)对永磁同步电动机矢量控制策略,实现了速度环的闭环控制。该控制方法通过精确调控电机磁场与电流的相位关系,优化电机运行效率,并显著提升油井开采的启动转矩和整体传输效率。研究成果有望为开发后期油井的高效、节能开采提供新的技术路径与解决方案。

采用螺杆膨胀机的汽电双驱技术在化工厂的应用研究

螺杆膨胀机是近年来受到广泛关注的低温余热回收技术,在化工厂余热利用中相比汽轮机具有良好的适应性。介绍了采用螺杆膨胀机实现汽电双驱的技术,及其在化工厂的应用研究。

超(特)高压线路大吨位荷载转移的双轴传动省力丝杠研究

输电领域现有的均为单轴传动模式,远不满足大档距大吨位力的转移要求。针对上述问题进行研究,提出使用双轴传动省力丝杠替代传统单轴丝杠,提高丝杠受力吨位,以满足超(特)高压线路大档距受力大的绝缘子更换要求。

“互联网+”螺杆泵智能直驱装置系统节能增效

基于“信息化、节能降耗、安全环保”为目的,联合研制“互联网+”螺杆泵智能直驱装置系统。该系统由螺杆泵交流永磁直驱同步电动机、螺杆泵数字化变频控制柜和抽油杆柔性防反转电磁制动器等组成。智能化程度高,运行稳定,提效增产。该装置系统在胜坨油田14口螺杆泵采油井进行替换试验,2021—2023年共节电29.4862×10^(4)kWh,节能率为19.93%,节能降耗效果好。

螺杆桩自动定位成桩工艺在软基处理中的应用

研究了螺杆桩自动定位成桩工艺在软基处理中的应用。软基是土木工程中常见的地基类型,其稳定性对工程的安全性和长期使用性具有重要影响。提出了一种基于螺杆桩的自动定位成桩工艺,通过引入现代化的测量和控制技术,实现了在软基处理过程中的高精度成桩定位。实验结果表明,螺杆桩自动定位成桩工艺可以显著提高软基处理的效率和准确性,降低工程成本,并改善工程的稳定性和使用寿命。

助飞运载器螺旋传动失效的机理研究

助飞运载器的螺旋传动缺乏摩擦及温升对其传动的作用机制研究。建立这种螺旋传动机构的热机耦合模型,并利用真实参数模拟传动接触面的热、力学等特性,通过分析应力、温升数据及其与摩擦系数之间的规律,揭示该螺旋传动的失效机制。数值模拟结果表明,该螺旋传动在大载荷的高速摩擦作用下,其传动接触面的温度能快速升至454.3℃,其接触应力可达699.4 MPa,高温降低了接触面的材料强度,因此高速滑动的摩擦力将对接触面造成持续破坏,计算结果和故障现象一致,研究成果也对该传动技术的工程应用提供了理论基础。