Mechanism and Machine Theory最新文献

Transmission angle of planar four-bar linkages applicable for different input-output links subject to external loads 平面四杆连杆机构的传动角，适用于承受外部载荷的不同输入输出连杆机构

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-11-01 DOI: 10.1016/j.mechmachtheory.2024.105829

{"title":"Transmission angle of planar four-bar linkages applicable for different input-output links subject to external loads","authors":"","doi":"10.1016/j.mechmachtheory.2024.105829","DOIUrl":"10.1016/j.mechmachtheory.2024.105829","url":null,"abstract":"<div><div>The transmission angle is a traditional performance indicator in planar four-bar linkages, whereby force and motion are transmitted from the input link to the output link. However, for the calculation of traditional transmission angle, it is predefined that the input and output links are connected to the fixed link, i.e., the grounded link. This brings the problem of calculating the transmission angle for other cases, for example, the coupler link being the input link. Moreover, the traditional transmission angle cannot evaluate the influence of external loads on the transmission quality. In this work, we revisit this problem and redefine the transmission angle, which allows us to investigate the effect of different selections of the input and output links and external loads on the transmission performance. A case study of transmission angle analysis of a planar four-bar linkage is included to illustrate the application of the revised performance index. Moreover, three new transmission quality indices are introduced, upon which transmission performance optimization of a planar four-bar linkage is presented. Based on the redefined transmission angle and the proposed transmission quality indices, transmission quality analysis and optimal design of general four-bar linkages can be conducted to enhance their transmission performances.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573443","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

Optimizing natural frequencies in compliant mechanisms through geometric scaling 通过几何缩放优化顺变机构的固有频率

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-11-01 DOI: 10.1016/j.mechmachtheory.2024.105822

{"title":"Optimizing natural frequencies in compliant mechanisms through geometric scaling","authors":"","doi":"10.1016/j.mechmachtheory.2024.105822","DOIUrl":"10.1016/j.mechmachtheory.2024.105822","url":null,"abstract":"<div><div>This work contributes to the dynamic analysis and optimization of compliant mechanisms in terms of their natural frequencies. The previously established analytical method based on Bernoulli beams and the transfer matrix method, which underlies the existing calculation tool <em>CaTEf</em>, is extended to enable the scaling of any specified geometric parameter or parameter set within a given mechanism to achieve a desired natural frequency. By introducing a scaling parameter, precise adjustments of selected geometric parameters are ensured while accounting for inherent dependencies. Minor discrepancies are revealed in parameter studies when comparing results obtained with our proposed analytical method to those from the Finite Element Method (FEM) regarding the resulting scaled values. Following validation, the analytical method is seamlessly integrated into <em>CaTEf</em> and verified against experimental data, demonstrating strong agreement. This work results in a highly efficient analytical method for optimizing compliant mechanisms in terms of their dynamic behavior, especially natural frequencies, while significantly reducing modeling and calculation time.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142573439","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

Oriblock: The origami-blocks based on hinged dissection Oriblock：基于铰链解剖的折纸块

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-10-30 DOI: 10.1016/j.mechmachtheory.2024.105826

{"title":"Oriblock: The origami-blocks based on hinged dissection","authors":"","doi":"10.1016/j.mechmachtheory.2024.105826","DOIUrl":"10.1016/j.mechmachtheory.2024.105826","url":null,"abstract":"<div><div>Traditional origami, a well-known art of paper-folding, does not account for material thickness. Subsequently, several thickness-accommodation techniques have been developed, considering the non-negligible thickness of materials, which enables the application of origami to a wide range of mechanisms. Although these techniques prevent self-intersections and preserve kinematics after accommodating panel thickness, they are limited by their reliance on initial zero-thickness origami patterns in two dimensions. To address this issue, this study proposes a novel technique, the volume-accommodation technique in three-dimensional space, which allocates non-coplanar origami creases based on solid geometry to allow a greater variety of shape-changing motions. Typical solid geometries, such as a pyramid and a prism, are selected as examples to demonstrate the design procedures. Closure equations of the obtained oriblock are used to analyze the kinematic properties. Additionally, Bennett and Myard Linkages are derived from oriblocks based on their kinematic equivalence to strengthen their connections. As a result, this new type of origami can offer a variety of mechanisms for designers and facilitate potential applications in origami-inspired metamaterials and robotics.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142554756","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 comprehensive study of the effect of thermal deformation on the dynamic characteristics of the high-speed spindle unit with various preload forces 不同预紧力下热变形对高速主轴单元动态特性影响的综合研究

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-10-30 DOI: 10.1016/j.mechmachtheory.2024.105820

引用次数: 0

Analysis of nonphysical attraction force and new coefficient of restitution based on a nonlinear viscoelastic contact model in cohesionless granular system 基于非线性粘弹性接触模型的无内聚力颗粒体系中的非物理吸引力和新的恢复系数分析

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-10-28 DOI: 10.1016/j.mechmachtheory.2024.105821

{"title":"Analysis of nonphysical attraction force and new coefficient of restitution based on a nonlinear viscoelastic contact model in cohesionless granular system","authors":"","doi":"10.1016/j.mechmachtheory.2024.105821","DOIUrl":"10.1016/j.mechmachtheory.2024.105821","url":null,"abstract":"<div><div>This investigation implements systematical research on the coefficient of restitution (CoR) and nonphysical attraction force. Firstly, a characteristic length is redefined based on energy conservation. On this basis, a new general CoR model is derived through characteristic length. Subsequently, a new constraint equation of the power exponents is proposed from the new CoR model. The new CoR model is validated by experimental data regardless of whether the initial impact velocity is very low or high speed. Secondly, we systematically analyze the real reason for the nonphysical attraction force in the viscous damping loop. The simulation shows the nonphysical attraction force cannot be removed from the viscous damping loop. The real reason for the nonphysical attraction force lies in the natural property of the viscous damping factor. Finally, to eliminate the effect of the attraction force on the motion status of colliding particles after impact, a balance coefficient is introduced to compensate for the deficiency of nonphysical attraction force and original damping factor. The simulation proves that the post-impact velocity of colliding particles can be precisely captured using a viscous contact force model with a balance coefficient.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536011","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 planar anti-buckling compliant rotational joint with a remote center of motion 设计和优化具有远程运动中心的平面抗弯曲顺应旋转接头

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-10-28 DOI: 10.1016/j.mechmachtheory.2024.105816

{"title":"Design and optimization of a planar anti-buckling compliant rotational joint with a remote center of motion","authors":"","doi":"10.1016/j.mechmachtheory.2024.105816","DOIUrl":"10.1016/j.mechmachtheory.2024.105816","url":null,"abstract":"<div><div>Compliant mechanisms (CMs) exhibit some excellent mechanical properties and provide numerous innovative solutions for many existing mechanical applications. Among them, planar compliant rotational joints have made substantial contributions to precision engineering. To achieve high-precision positioning with a compliant rotational joint, it is essential to study characteristics such as anti-buckling and constant stiffness. The remote center of motion (RCM) mechanism, with its compact structure and ease of precise control, is expected to enhance overall rigidity and reduce parasitic displacements. Here, we propose a planar anti-buckling compliant rotational joint with a RCM. Static modeling and model validation are conducted for different geometric configurations, including single and combined structures. A distributed configuration with bidirectional anti-buckling properties is selected for optimization. Using a global parameter optimization model, single-objective optimization studies are conducted for three distinct characteristics. Subsequently, a multi-objective optimization model for constant stiffness and high precision is established. Based on the optimization results, a compliant rotational joint with bidirectional anti-buckling, constant rotational stiffness, and high precision is designed. Finally, the effectiveness of the optimization method is validated through physical experiments.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536010","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

Modelling of the objects' positioning process on the conveyor with the positioning rectilinear barrier and the system of driven oblique rollers 利用定位直线屏障和驱动斜辊系统对输送机上的物体定位过程进行建模

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-10-25 DOI: 10.1016/j.mechmachtheory.2024.105817

{"title":"Modelling of the objects' positioning process on the conveyor with the positioning rectilinear barrier and the system of driven oblique rollers","authors":"","doi":"10.1016/j.mechmachtheory.2024.105817","DOIUrl":"10.1016/j.mechmachtheory.2024.105817","url":null,"abstract":"<div><div>The paper deals with the positioning process modelling of the cuboidal objects along the conveyor edge by means of an oblique friction force field with a rectilinear barrier. The friction field is created by a system of driven oblique rollers. A modified nonlinear Kelvin model was used to describe the normal reaction forces at the contact points of the object with the conveyor and barrier. There were taken into account two 2D vector friction models: the LuGre and the Bengisu-Akay, representing the dynamic and static groups of friction models, respectively. The LuGre model has been modified to overcome the limitations of the classic model in terms of the invariability of the normal contact forces. The use of scaling of the stiffness coefficient (due to the normal contact force) allows the friction simulation while bodies collision, i.e. when the normal contact force shows rapid changes in value and the initial sliding velocity is non-zero. A method for determining the dynamic parameters of the LuGre model is proposed. The results of numerical and experimental research on the positioning process show acceptable compliance and validity of the adopted assumptions.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536009","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

Development of an analytical model and method for analyzing deformation in planar load cells 开发用于分析平面称重传感器变形的分析模型和方法

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-10-23 DOI: 10.1016/j.mechmachtheory.2024.105812

{"title":"Development of an analytical model and method for analyzing deformation in planar load cells","authors":"","doi":"10.1016/j.mechmachtheory.2024.105812","DOIUrl":"10.1016/j.mechmachtheory.2024.105812","url":null,"abstract":"<div><div>Due to their advantageous properties, compliant mechanisms are widely used in various technical fields. Strain-based deformation bodies, a particular type of these mechanisms, are often used in weighing technology. They are used in conjunction with strain gauges for force measurement, among other applications. Until now, such weighing mechanisms have been designed using finite element simulations or empirical studies, which are often time-consuming and costly. Therefore, this article presents an analytical calculation model based on the theory of large deformations of rod-like structures, which simplifies the calculation of such weighing mechanisms. Key elements in this calculation are the transversally symmetric hinges required for the description. Investigations show that, due to the geometry of these cells, tensile and compressive deformations are not negligible and must be included in the analytical model. The validity and accuracy of the analytical model are verified through parameter studies and show deviations of less than 6% compared to the FEM. Finally, the model is integrated into a graphical user interface to allow an easy application to analyze load cells.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536008","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

The friction-limited end-effector motion resolution of tendon-actuated and continuum robots 腱驱动机器人和连续机器人的摩擦限制末端执行器运动分辨率

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-10-23 DOI: 10.1016/j.mechmachtheory.2024.105814

{"title":"The friction-limited end-effector motion resolution of tendon-actuated and continuum robots","authors":"","doi":"10.1016/j.mechmachtheory.2024.105814","DOIUrl":"10.1016/j.mechmachtheory.2024.105814","url":null,"abstract":"<div><div>Force and motion transmission losses can significantly affect the kinematics and performance of wire-actuated robots. In addition to degrading the kinematic model, they can produce hysteresis (dead-zone) effects whereby the motion of the actuators produces no motion of the end effector. This paper presents a modeling framework that can be used at the design stage to evaluate the effects of these transmission losses. Considerations for modeling the dead-zone effects of end-effector motion are used to define a performance measure that quantifies the quality of a given design within a workspace. This design measure should be used in conjunction with the traditional kinematics and statics-based measures to reflect the expected performance of an integrated wire-actuated robot with its actuation lines and actuation unit. To illustrate our approach, we present a model of a wire-actuated snake-like robot with an articulated backbone made up of ball-and-socket joints. The results and methodology reported in this paper can guide the design of wire-actuated robots in selecting wire-parameters and determining their effects on the expected uncertainty, limiting the friction-limited minimal motion resolution of the end effector.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536007","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

Reducing backward motion of stick-slip piezoelectric actuators using dual driving feet designed by asymmetric stiffness principle 利用非对称刚度原理设计的双驱动脚减少粘滑压电致动器的后向运动

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2024-10-21 DOI: 10.1016/j.mechmachtheory.2024.105810

{"title":"Reducing backward motion of stick-slip piezoelectric actuators using dual driving feet designed by asymmetric stiffness principle","authors":"","doi":"10.1016/j.mechmachtheory.2024.105810","DOIUrl":"10.1016/j.mechmachtheory.2024.105810","url":null,"abstract":"<div><div>Stick–slip piezoelectric actuators (SSPEAs) have drawn attention for their features of simple structure and high positioning accuracy. However, the backward motion has always been a major problem that limits driving speed and smoothness. Existing methods mainly focus on control methods and driving signal optimization, while few efforts emphasize mechanical structure optimization. To address this problem from the root of structure design, a novel SSPEA based on the principle of asymmetric stiffness is developed. A dual-driving feet configuration generates phase differences between two feet when feeding sawtooth driving signals. The core idea is that the backward motion of one driving foot can be compensated by another foot making full use of the phase difference due to the asymmetric stiffness compliant mechanism (ASCM). Kinematic and static models are built and the structural dimensions are then determined. Finite element analysis is conducted preliminarily to test the output performance. A physical prototype is fabricated and experimentally verified. Experimental results show the proposed actuator with ASCM achieves smaller backward motion and larger step size ranging from 250 to 1400 Hz driving frequencies compared with traditional triangular compliant mechanism (TTCM). The maximum speed is obtained as 47.2 mm/s with a resolution of <span><math><mrow><mn>0</mn><mo>.</mo><mn>07</mn><mspace></mspace><mi>μ</mi><mi>m</mi></mrow></math></span>.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":null,"pages":null},"PeriodicalIF":4.5,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142536006","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