Mechanism and Machine Theory最新文献_第5页

A revised framework for ball-screw contact kinematics 滚珠丝杠接触运动学的修正框架

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2025-12-16 DOI: 10.1016/j.mechmachtheory.2025.106317

Pello Alberdi, Aitor Arana, Aitor Oyanguren, Jon Larrañaga, Ibai Ulacia

Ball screw mechanisms are widely used in precision applications due to their high stiffness and efficiency. However, unlike ball bearings, the helical geometry of ball screws leads to multidirectional contact kinematics, which significantly influence friction, wear, and overall performance. In the classical contact kinematic formulation, the velocity components of the ball are not fully projected onto the contact interface, resulting in significant errors in the calculation of contact kinematics.

This work presents a revised contact kinematic formulation considering all the missing components, and revealing substantial differences in the prediction which alters the conventional understanding of contact kinematics in ball screws. The contact kinematics are broken down into their fundamental components-rolling, side, and spinning slip-and analytical expressions for each are introduced. A new characterisation framework based on three independent variables is proposed, quantifying the distinct effects of rolling, side, and spinning motion more comprehensively than traditional single SRR.

The proposed model is first validated against a well-established ball bearing formulation (i.e. ball screw with no lead), confirming its accuracy under such geometry. At the ball screw scale, the results reveal substantial deviations from existing models. Side slip emerges as the dominant mechanism, fundamentally revising the conventional interpretation of contact kinematics. Furthermore, the new three-variable framework enables a more complete and accurate characterisation of the contact behaviour, offering valuable insights for tribological modelling and performance optimisation. Finally, a parametric analysis is conducted to examine the influence of key kinematic constraints on the sliding behaviour, highlighting the independent role of each in defining the contact kinematics.

滚珠丝杠机构因其高刚度和高效率而广泛应用于精密领域。然而，与滚珠轴承不同，滚珠丝杠的螺旋几何形状导致多向接触运动学，这显著影响摩擦、磨损和整体性能。在经典的接触运动学公式中，球的速度分量没有完全投影到接触界面上，导致接触运动学计算存在较大误差。这项工作提出了一个考虑所有缺失部件的修订接触运动学公式，并揭示了预测中的实质性差异，这改变了对滚珠丝杠接触运动学的传统理解。将接触运动学分解为滚滑、侧滑和旋滑三个基本分量，并介绍了每个基本分量的解析表达式。提出了一种新的基于三个自变量的表征框架，比传统的单一SRR更全面地量化了滚动、侧转和旋转运动的不同影响。提出的模型首先针对一个完善的滚珠轴承公式（即无导丝杠）进行验证，确认其在这种几何形状下的准确性。在滚珠丝杠尺度上，结果显示与现有模型有很大的偏差。侧滑作为主导机制出现，从根本上改变了接触运动学的传统解释。此外，新的三变量框架能够更完整、更准确地描述接触行为，为摩擦学建模和性能优化提供有价值的见解。最后，进行参数分析以检查关键运动学约束对滑动行为的影响，强调每个约束在定义接触运动学中的独立作用。

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引用次数: 0

Time-varying meshing stiffness model of the idler ring bearing in planetary gear train 行星轮系惰环轴承时变啮合刚度模型

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2025-12-16 DOI: 10.1016/j.mechmachtheory.2025.106322

Yu Liu , Xinyuan Li , Hao Liu , Hui Ma

This study investigates the coupled deformation mechanism and time-varying meshing stiffness of thin-walled ring gears with integrated idler gear bearings in aerospace planetary transmission systems. Based on a self-balanced virtual support model and thin-walled ring theory, influence coefficient formulas for the radial displacement and rotation at the gear root were derived, and an analytical model of ring gear deformation considering roller phase relations was established. By formulating the nonlinear relationship between radial displacement, rotation, and roller rotation angle, a foundation stiffness model of the gear–idler gear bearing system was developed. Furthermore, a time-varying meshing stiffness model was proposed using the potential energy method. Comparison with finite element results validated the proposed approach. The findings reveal that roller support significantly enhances the ring gear foundation stiffness; an increased speed ratio between the cage and ring gear increases meshing stiffness, whereas a higher roller rotational speed increases stiffness due to centrifugal effects. This work provides theoretical guidance for stiffness optimization and dynamic design of thin-walled ring gear planetary systems with idler gear bearings.

研究了航空航天行星传动系统中集成惰轮轴承薄壁环齿的耦合变形机理和时变啮合刚度。基于自平衡虚拟支撑模型和薄壁环理论，推导了齿根径向位移和旋转的影响系数公式，建立了考虑滚子相位关系的环齿变形解析模型。通过建立径向位移、转动和滚子转角之间的非线性关系，建立了齿轮-惰轮轴承系统的基础刚度模型。在此基础上，利用势能法建立了时变网格刚度模型。与有限元结果的对比验证了所提方法的有效性。研究结果表明：滚柱支撑显著提高了环齿基础刚度；保持架和环形齿轮之间增加的速比增加了啮合刚度，而较高的滚子转速由于离心效应而增加了刚度。该研究为带惰轮轴承的薄壁环齿行星系统的刚度优化和动力学设计提供了理论指导。

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引用次数: 0

A globally discretized ALE beam model for cable-driven parallel robots with large deformations 大变形索驱动并联机器人的全局离散ALE梁模型

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2025-12-16 DOI: 10.1016/j.mechmachtheory.2025.106321

Zheng Chen, Hui Ren, Ping Zhou, Wei Fan

Three-dimensional (3D) beam structures with large deformations and sliding boundaries face critical challenges in balancing accuracy and computational efficiency. To overcome these limitations, a novel globally discretized Arbitrary Lagrangian-Eulerian beam model is proposed for 3D large deformation dynamic analysis. Analytical assumed modes of sectional angles and strains are adopted for global discretization, capturing complex deformations with minimal degrees of freedom. Explicit derivations of both configurational forces and governing equations for large overall motions are achieved. An explicit integration scheme with updating rotation on the SO(3) manifold is proposed to efficiently solve the weak stiff equations of slender cables. An implicit integration scheme is adopted for thick beams with full strain consideration, where analytically derived Jacobian matrices are utilized to enhance computational performance. Numerical results show that the present model demonstrates >80 % reduction in degrees of freedom while maintaining high accuracy. Its efficacy is further proven through the cable-driven parallel robots, achieving real-time capability for large-scale applications. The current approach shows promising potential for modeling other sliding-boundary systems, such as concentric-tube soft robots and variable-length space manipulators.

具有大变形和滑动边界的三维梁结构在平衡精度和计算效率方面面临着严峻的挑战。为了克服这些局限性，提出了一种新的全局离散化任意拉格朗日-欧拉梁模型，用于三维大变形动力分析。采用截面角和应变的解析假设模态进行全局离散化，以最小自由度捕获复杂变形。实现了大整体运动的构型力和控制方程的显式推导。为了有效地求解细长索的弱刚性方程，提出了一种基于SO(3)流形的旋转更新显式积分方案。对于考虑全应变的厚梁，采用隐式积分方案，利用解析导出的雅可比矩阵提高计算性能。数值结果表明，该模型在保持较高精度的同时，自由度降低了80%。通过电缆驱动的并联机器人进一步证明了其有效性，实现了大规模应用的实时能力。目前的方法显示了对其他滑动边界系统建模的潜力，如同心管软机器人和变长空间操纵器。

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引用次数: 0

Corrigendum to “Kinematics of rolling contact: Derivation, misconceptions, and generalisations” [Mechanism and Machine Theory 216 (2025) 106201] “滚动接触运动学：推导、误解和概括”的勘误表[机械与机械理论216 (2025)106201]

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2025-12-13 DOI: 10.1016/j.mechmachtheory.2025.106298

Luigi Romano, Sweden Linköping

引用次数: 0

Cavitation mechanism of high-speed gears with misalignment 高速齿轮失对空化机理研究

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2025-12-13 DOI: 10.1016/j.mechmachtheory.2025.106319

Tiancheng Ouyang , Hongyang Tian , Yang Yang , Shaohui Qin , Yong Chen

In high-speed gear transmissions, cavitation is prone to occur, leading to vibration deterioration and tooth surface erosion. Vibration and engagement characteristics become abnormal when misalignment inevitably occurs due to mounting errors, deformation and long-term wear. However, current gear cavitation studies are set to ideal alignment and it is not clear how misalignment affects cavitation. To investigate the cavitation mechanism in misaligned gears, a kinetic model of misaligned gears is combined with a turbulence model with cavitation for the first time. First, the abnormal vibration responses that derived from the gear finite element model are validated against existing experimental results, and they are applied as boundary rotation conditions for the flow field. Subsequently, the effects of vibration and meshing discrepancies caused by different misalignments on cavitation are comprehensively analyzed. Vapor and pressure distributions in the meshing zone are examined to evaluate the impacts of misalignment degree, rotational speed, vibration, and tooth surface meshing. Results indicate that gear pairs with misalignment exhibit significant cavitation phenomena during high-speed operation. Specifically, vibration amplification induced by radial and yaw misalignments exacerbate the severity of cavitation.

在高速齿轮传动中，容易产生空化现象，导致振动恶化和齿面侵蚀。当由于安装误差、变形和长期磨损而不可避免地出现不对准时，振动和啮合特性就会异常。然而，目前的齿轮空化研究是设定为理想的对准，不清楚不对准如何影响空化。为了研究齿对空化机理，首次将齿对空化动力学模型与考虑空化的湍流模型相结合。首先，将齿轮有限元模型得到的异常振动响应与已有的实验结果进行验证，并将其作为流场的边界旋转条件。在此基础上，综合分析了不同对准误差引起的振动和啮合误差对空化的影响。研究了啮合区域内的蒸汽和压力分布，以评估误差程度、转速、振动和齿面啮合的影响。结果表明，齿轮副在高速运行过程中存在明显的空化现象。具体而言，径向和偏航错位引起的振动放大加剧了空化的严重程度。

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引用次数: 0

Derailment mechanism analysis of subway vehicles under air spring failure 空气弹簧失效下地铁车辆脱轨机理分析

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2025-12-11 DOI: 10.1016/j.mechmachtheory.2025.106316

Bo Wang , Qing Wu , Hailiang Yu , Weihua Ma , Feng Lin , Xiangyu Li , Xueqiang Zhang

To analyze the derailment mechanism of a subway train under air spring failure conditions and to identify improvement measures, this study first establishes a dynamic train model according to the actual train formation. Subsequently, equivalent models for air spring failure are introduced. Finally, based on wheel–rail derailment theory and vehicle system dynamics, a comparative analysis is conducted under both normal (inflated) and failed air spring conditions to investigate key factors influencing the derailment mechanism. Corresponding improvement measures are then proposed. The results indicate that: (1) with air spring failure, curve transition derails the train; (2) multiple factors can effectively lower derailment risks; (3) large lateral creep force and attack angle are not necessary conditions for flange climbing; and (4) installing guard rails at curve exits and applying lubrication to the rails can effectively reduce flange climbing risk under air spring failure. This study provides valuable insights for subway track design and for mitigating derailment risks in the event of air spring failure.

为了分析空气弹簧失效条件下地铁列车的脱轨机理，确定改进措施，本研究首先根据实际列车编队建立了动态列车模型。随后，介绍了空气弹簧失效的等效模型。最后，基于轮轨脱轨理论和车辆系统动力学，对正常（充气）空气弹簧和失效空气弹簧进行了对比分析，探讨了影响轮轨脱轨机理的关键因素。并提出了相应的改进措施。结果表明：(1)空气弹簧失效时，曲线过渡使列车脱轨；(2)多因素有效降低脱轨风险；(3)侧向蠕变力大、攻角大不是法兰爬升的必要条件；(4)在弯道出口处安装护栏并对护栏进行润滑，可有效降低空气弹簧失效时法兰爬升的风险。该研究为地铁轨道设计和减少空气弹簧失效时的脱轨风险提供了有价值的见解。

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引用次数: 0

Driving rotational motion with Euler parameters: a constraint formulation for multibody systems 用欧拉参数驱动旋转运动：多体系统的约束公式

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2025-12-10 DOI: 10.1016/j.mechmachtheory.2025.106315

Madalena Antunes, João Folgado, Carlos Quental

The formulation of rotational driving constraints using angular variables (angle-based formulation) may introduce numerical instabilities and redundancy among kinematic constraints, which can compromise the robustness of multibody analyses. This study proposes an alternative Euler-based formulation, in which Euler parameters, describing the relative orientation between joint-connected bodies, are used to define rotational driving constraints. This formulation avoids singularities, enables full range of motion evaluation, and eliminates redundancy. Both angled-based and Euler-based formulations were applied to different joints within both open and closed kinematic chains using an in-house multibody model of the human body. Kinematic and inverse dynamic analyses were conducted across several movements from multiple subjects, and the results were compared between the two formulations and literature data. The Euler-based formulation provided independent kinematic constraints and showed good agreement with joint kinematics and torques from established methods. In addition, it improved computational efficiency. Overall, the use of Euler parameters offers a robust and efficient alternative to angle-based formulations for rotational driving constraints in multibody system dynamics.

使用角度变量的旋转驱动约束公式（基于角度的公式）可能会引入数值不稳定性和运动约束之间的冗余，从而影响多体分析的鲁棒性。本研究提出了一种基于欧拉的替代公式，其中欧拉参数用于描述关节连接体之间的相对方向，以定义旋转驱动约束。这个公式避免了奇点，使全范围的运动评估，并消除了冗余。使用人体内部多体模型，将基于角度和基于欧拉的公式应用于开放和封闭运动链中的不同关节。运动学和逆动力学分析在多个受试者的几个运动中进行，并将结果与两种公式和文献数据进行比较。基于欧拉的公式提供了独立的运动学约束，并与现有方法的关节运动学和扭矩具有良好的一致性。此外，它还提高了计算效率。总的来说，欧拉参数的使用为多体系统动力学中旋转驱动约束的基于角度的公式提供了一种鲁棒和高效的替代方案。

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引用次数: 0

Type synthesis of reconfigurable single-loop mechanisms based on transitional configurations 基于过渡构型的可重构单环机构类型综合

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2025-12-06 DOI: 10.1016/j.mechmachtheory.2025.106306

Jun Cai , Wang Yu , Bing Li , Sen Wang , Fujun Peng

This paper presents a general type synthesis methodology for reconfigurable single-loop mechanisms (RSLMs). Unlike conventional approaches that derive RSLMs from classical configurations, this study investigates constraint system variations during transitional configurations of RSLMs. When the RSLM is in transitional configuration, the order of wrench systems reaches its peak. Utilizing this characteristic, we categorize wrench systems according to their order and type, then construct the original single-loop mechanism through the closure of the corresponding wrench system's open-loop kinematic chains. Subsequently, while maintaining the original wrench system configuration, kinematic pairs are added. Further analysis of inactive joints and mechanism reconfiguration characteristics, the optimized RSLM configuration is synthesized. The proposed method generates more generalized RSLM configurations and ensures that the RSLM created is in transitional configurations, thereby facilitating subsequent motion pattern analysis. As validation, multiple novel 6R and 7R RSLMs with single DOF reconfigurability have been successfully synthesized, demonstrating the method's feasibility and effectiveness. Finally, optimization strategies for eliminating inactive joints and structural refinement are proposed. Two application-oriented prototypes are presented to exemplify the practical potential of the synthesized RSLMs.

本文提出了可重构单环机构的一般类型综合方法。与从经典构型推导rslm的传统方法不同，本研究考察了rslm过渡构型中的约束系统变化。当RSLM处于过渡构型时，扳手系统的顺序达到峰值。利用这一特性，对扳手系统按顺序和类型进行分类，并通过闭合相应扳手系统的开环运动链来构造原始的单环机构。随后，在保持原有扳手系统配置的同时，增加了运动副。进一步分析了非活动关节和机构重构特征，综合了优化后的RSLM构型。该方法生成了更一般化的RSLM构型，并确保所创建的RSLM处于过渡构型，从而便于后续的运动模式分析。作为验证，成功合成了多个具有单自由度可重构性的新型6R和7R rslm，验证了该方法的可行性和有效性。最后，提出了消除非活动关节和结构精细化的优化策略。提出了两个面向应用的原型，以说明综合rslm的实际潜力。

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引用次数: 0

Layout optimization of compliant mechanism with embedded components using moving morphable component (MMC) method 基于移动可变形构件法的嵌入式柔性机构布局优化

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2025-12-04 DOI: 10.1016/j.mechmachtheory.2025.106301

Min Liu , Liwen Lu , Jinqing Zhan , Benliang Zhu , Hua Wang , Xianmin Zhang

This paper proposes a single explicit topology optimization method based on the moving morphable component framework for the integrated design of the movable components and compliant mechanism. The core of this method lies in the unified use of explicit geometric parameters (size and pose) to describe the topological configuration and layout of the mechanism and embedded components, avoiding the model complexity and dual sensitivity analysis issues associated with hybrid description frameworks. Based on this unified description framework, a topological description function for the compliant mechanism with embedded components is constructed, and finite element analysis is performed using the ersatz material model. Under the volume constraint of the host structure, an optimization model is established with the goal of maximizing the output displacement. Sensitivity analysis is done analytically, and the design variables are updated using the method of moving asymptotes approach. Numerical examples verify the effectiveness of this method in the integrated design of embedded components and compliant mechanisms.

提出了一种基于可动构件框架的单显式拓扑优化方法，用于可动构件与柔性机构的集成设计。该方法的核心在于统一使用显式几何参数（尺寸和位姿）来描述机构和嵌入式部件的拓扑构型和布局，避免了混合描述框架的模型复杂性和双灵敏度分析问题。在此统一描述框架的基础上，构建了嵌入式构件柔性机构的拓扑描述函数，并利用伪材料模型进行了有限元分析。在主体结构体积约束下，以输出位移最大化为目标，建立了优化模型。采用解析法进行灵敏度分析，并采用移动渐近线法更新设计变量。数值算例验证了该方法在嵌入式构件与柔性机构集成设计中的有效性。

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引用次数: 0

Closed-form forward kinematics, singularity, dexterity and workspace analyses of a special class of 3-RRR spherical parallel mechanisms 一类特殊的3-RRR球面并联机构的闭式正运动学、奇异性、灵巧性和工作空间分析

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2025-12-04 DOI: 10.1016/j.mechmachtheory.2025.106288

Shuai Zhang , Wei Li , Huayan Pu , Rui Chen , Jun He , Jun Luo

3-RRR spherical parallel mechanisms (SPMs) are capable of producing three-DOF spherical motion, which can find applications in various fields. This paper investigates the kinematics and workspace performance of a particular class of 3-RRR SPMs, characterized by coaxial input-joint axes, coplanar distal-joint axes, and six orthogonal links. First, two novel formulations are proposed for the forward kinematics (FK) of this robot class, both resulting in linear univariate polynomials that significantly streamline the FK formulation and reduce the computational complexity. Moreover, this robot class exhibits minimal and physically interpretable singularity loci in both the orientation workspace and the input joint space, greatly facilitating singularity avoidance and path planning. Furthermore, local and global dexterity indices are employed to analyze the mechanism’s performance, from which the architectural parameters yielding optimal dexterity are identified. Finally, the robot class demonstrates a considerably large tilt-torsion orientation workspace when the architectural parameters and link shapes are appropriately selected, allowing for infinite torsional motion when pointed within almost a hemisphere. The foregoing features make the robot class potentially promising in a wide range of applications.

3-RRR球面并联机构（SPMs）具有三自由度球面运动的能力，在各个领域都有广泛的应用。本文研究了一类具有同轴输入关节轴、共面远关节轴和六个正交连杆的3-RRR SPMs的运动学和工作空间性能。首先，对该类机器人的正运动学（FK）提出了两种新颖的公式，均得到线性单变量多项式，大大简化了FK的公式，降低了计算复杂度。此外，该类机器人在姿态工作空间和输入关节空间中都具有最小且物理可解释的奇异轨迹，极大地促进了奇异避免和路径规划。此外，采用局部和全局灵巧度指标分析机构的性能，从而确定最优灵巧度的结构参数。最后，当适当选择结构参数和连杆形状时，机器人类展示了相当大的倾斜-扭转方向工作空间，当指向几乎一个半球时，允许无限扭转运动。上述特点使得该类机器人具有广泛的应用前景。

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引用次数: 0