Mechanism and Machine Theory最新文献_第4页

Analytical determination of the optimal effective regular workspace of a 6-6 Stewart platform manipulator for a specified orientation workspace 分析确定指定方向工作空间的 6-6 斯图尔特平台机械手的最佳有效规则工作空间

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-09-20 DOI: 10.1016/j.mechmachtheory.2024.105791

{"title":"Analytical determination of the optimal effective regular workspace of a 6-6 Stewart platform manipulator for a specified orientation workspace","authors":"","doi":"10.1016/j.mechmachtheory.2024.105791","DOIUrl":"10.1016/j.mechmachtheory.2024.105791","url":null,"abstract":"<div><div>This article presents an analytical method to identify the largest <em>effective regular workspaces</em> (ERWs) of a class of 6-6 Stewart platform manipulators for a given orientation workspace. The ERWs are modelled as spheres. The orientation workspace is specified in terms of ranges of Euler angles, as is the standard practice in the parallel robot industry. The radius of the said sphere is maximised through an optimisation problem, which is solved analytically. Consequently, the results obtained are <em>exact</em> in nature. The analytical formulation of the problem and its exact solutions constitute the novel theoretical contributions of this article. Moreover, since the results hold good over a given subset of <span><math><mrow><mi>SO</mi><mrow><mo>(</mo><mn>3</mn><mo>)</mo></mrow></mrow></math></span>, the proposed method obviates the need for numerical scanning of the orientation workspaces in design-related computations, thus improving the accuracy, robustness, as well as computational efficiency. Finally, the significance of the <em>neutral height</em> in harnessing the desired extents of position and orientation workspaces has been established through parametric studies. The formulations are illustrated via applications to Stewart platform manipulators of three distinct platform dimensions.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-09-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142310907","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A new iterative identification algorithm for estimating the LuGre friction model parameters 用于估计鲁格莱摩擦模型参数的新迭代识别算法

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-09-19 DOI: 10.1016/j.mechmachtheory.2024.105797

{"title":"A new iterative identification algorithm for estimating the LuGre friction model parameters","authors":"","doi":"10.1016/j.mechmachtheory.2024.105797","DOIUrl":"10.1016/j.mechmachtheory.2024.105797","url":null,"abstract":"<div><div>The parameters of dynamic friction models like the LuGre model are commonly identified by computationally intensive nonlinear optimization methods. In this paper, an alternative least-square-based iterative algorithm is proposed to simultaneously identify the LuGre model parameters and the inertial properties from a limited set of measurements. The LuGre model, expressed in two forms allowed independent identification of the static and dynamic parameters. Moreover, since the method uses response-input time–history instead of numerous constant velocity experiments (CVEs), both the inertial and friction parameters can be identified in much fewer experiments (theoretically one). A variant of the Sparse Identification of Nonlinear Dynamics method called SR3 is embedded in the algorithm to capture the nonlinear viscous friction and Stribeck effects in the friction model. Application of the algorithm to an industrial robot joint shows that the convergence of the algorithm is fast and the identified model is accurate in predicting the joint’s dynamics in a wide range of velocities. The friction-velocity curves resulting from the identified model are compared to those obtained by traditional CVEs to confirm the accuracy of the identified model.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142310906","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Transient analysis of non-uniform tilting-pad journal bearing for wind turbine main shaft under dynamical loading 风力涡轮机主轴非均匀斜垫式轴颈轴承在动态载荷下的瞬态分析

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-09-19 DOI: 10.1016/j.mechmachtheory.2024.105792

{"title":"Transient analysis of non-uniform tilting-pad journal bearing for wind turbine main shaft under dynamical loading","authors":"","doi":"10.1016/j.mechmachtheory.2024.105792","DOIUrl":"10.1016/j.mechmachtheory.2024.105792","url":null,"abstract":"<div><div>The non-uniform distributed tilting-pad journal bearing (NDTPJB), designed for large megawatt wind turbine main shafts, has not been assessed for transient stability under typical random wind conditions. Particularly, the dynamic interaction between low-speed, heavy-load operations with varying magnitude and direction, and the bearing's asymmetric structure, has not been fully explored. A new transient tribo-dynamic model is developed to analyze 6MW wind turbine's NDTPJB transient friction behavior, accounting for variable wind loads, pad distribution asymmetry, mixed lubrication (ML), and elastic pivot effects. Key parameters affecting tribo-dynamic friction performance—pad wrap angle, pad distribution count, and pivot stiffness—were comprehensively investigated. Findings show that dynamic loading cause asymmetrical behaviors in main and secondary pads, with performance significantly affected by the number of bottom distributed pads and improved stability with setting the number of above distributed pads to three. The stiffness of pivots significantly and complexly affects bearing dynamics, optimization of stiffness should be conducted after pad distribution determination. These discoveries guide further research and enhancements of NDTPJB in large rotating machinery under low-speed and heavy-load conditions.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142310905","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Design and optimization of a novel multi-layer conical Kresling origami mechanism (MCKOM) for linear actuation 设计和优化用于线性驱动的新型多层锥形克瑞斯林折纸机构 (MCKOM)

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-09-19 DOI: 10.1016/j.mechmachtheory.2024.105796

{"title":"Design and optimization of a novel multi-layer conical Kresling origami mechanism (MCKOM) for linear actuation","authors":"","doi":"10.1016/j.mechmachtheory.2024.105796","DOIUrl":"10.1016/j.mechmachtheory.2024.105796","url":null,"abstract":"<div><p>To address the inevitable twisting issue of modular configurations with different morphological parameters, this paper takes conical Kresling units as the research object, and a novel multi-layer conical Kresling origami mechanism (MCKOM) for linear actuation is designed. The main body consists of <em>m</em> serially connected flat-foldable bistable units with the same chirality but different morphological parameters. The design objective of achieving pure linear actuation under torque drive is realized by introducing external systems. Kinematic coupling and inner product models are established and multi-objective optimization algorithms are employed to optimize the structure. Based on optimized values, simulation and experimental validation of the motion behavior are conducted using ABAQUS and prototypes. The results show that the total twist angle decreased by 10.076° and the inner product increased by 60,291.98 mm<sup>3</sup>. Furthermore, the crease vertices cutting eliminates the influence of internal pressure on the guiding plate's outward deviation and increases the folding ratio from 41.49 % to 48.88 % under experimental conditions. The proposed novel pure linear actuation mechanism can be applied in actuation scenarios that require the conversion of rotational motion into linear displacement.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-09-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142242980","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A novel method of modelling contact dynamics for spur gear transmission 正齿轮传动接触动力学建模新方法

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-09-18 DOI: 10.1016/j.mechmachtheory.2024.105793

引用次数: 0

Numerical study on the effectiveness of the optimization of the load distribution in ball screw actuators 滚珠丝杠推杆载荷分布优化效果的数值研究

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-09-16 DOI: 10.1016/j.mechmachtheory.2024.105781

引用次数: 0

Optimization design and key-term separation identification of parallel six-dimensional pose sensor with high sensitivity and high precision 高灵敏度和高精度并行六维姿态传感器的优化设计和关键项分离识别

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-09-13 DOI: 10.1016/j.mechmachtheory.2024.105716

{"title":"Optimization design and key-term separation identification of parallel six-dimensional pose sensor with high sensitivity and high precision","authors":"","doi":"10.1016/j.mechmachtheory.2024.105716","DOIUrl":"10.1016/j.mechmachtheory.2024.105716","url":null,"abstract":"<div><p>The integrated bearing-positioning parallel manipulator is an important mean for ground testing of space optical telescope before being launched into space. To ensure positioning accuracy, the manipulator requires a pose sensor for the end-effector measurement with six degrees of freedom (DOF), real-time, high-precision, and operation in a vacuum environment. However, it is challenging for the current pose sensor to simultaneously meet all these requirements. In this paper, a novel concept of six-dimensional pose sensor based on parallel mechanism is proposed. A new mechanism design approach is presented to achieve the large measurement range, real-time measurement performance, and high accuracy measurement based on performance atlas. First, the G<sub>F</sub> sets synthesis is developed to optimize the configuration of pose sensor. Next, two new design indicators are proposed to evaluate the real-time and high accuracy performance. Mechanism parameters are optimized by combining with mechanism singularity analysis. To guarantee high measurement accuracy, a key-term separation identification method with double neural networks is presented. Experiments on 6-UPS pose sensor demonstrate the effectiveness of the proposed mechanism design and key-term identification approach.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-09-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142171897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Fast mobility analysis for generative design applications through a real vector space representation of mobilities 通过移动性的真实向量空间表示，为生成式设计应用提供快速移动性分析

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-09-11 DOI: 10.1016/j.mechmachtheory.2024.105790

{"title":"Fast mobility analysis for generative design applications through a real vector space representation of mobilities","authors":"","doi":"10.1016/j.mechmachtheory.2024.105790","DOIUrl":"10.1016/j.mechmachtheory.2024.105790","url":null,"abstract":"<div><p>During the early stages of design, mechanisms are commonly modeled as perfect joints assembled with infinitely rigid bodies. This representation enables the prediction of the system’s mobilities through a mobility analysis. However, traditional mobility analysis tools can be computationally expensive or lack critical information, such as the type or direction of mobilities. It hinders the generation of topology and configuration through generative design schemes.</p><p>In this paper, we propose an alternative approach to mobility analysis based on a real vector space representation of mobilities. Our method provides relevant information for early design steps while being computationally effective through a novel formulation of series and parallel assembly topological operations. A benchmark on four selected use cases highlights an acceleration of 3 to 4 orders of magnitude compared to traditional approaches. Additionally, design rules on the joints’ positions can be automatically generated with our approach. It enables the automation of the complete design process, including topology and configuration. As such, we provide guidelines to develop a generative design scheme dedicated to the synthesis of guiding mechanisms.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0094114X24002179/pdfft?md5=707d548a4597f571ad66ed948b72d5ec&pid=1-s2.0-S0094114X24002179-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142168575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Computerized generation, deviation correction and rapid tooth contact analysis of helical face gear 螺旋齿面齿轮的计算机生成、偏差修正和快速齿面接触分析

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-09-10 DOI: 10.1016/j.mechmachtheory.2024.105789

引用次数: 0

Kinematics of computationally efficient mechanisms 计算效率机制的运动学

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-09-09 DOI: 10.1016/j.mechmachtheory.2024.105782

引用次数: 0