Mechanism and Machine Theory最新文献_第3页

Lie algebra-based high-order constraint analysis of a novel multi-loop metamorphic mechanism derived from four-bar linkage for lower limb exoskeletons

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2025-03-22 DOI: 10.1016/j.mechmachtheory.2025.105994

Yusong Xing , Jun Wei , Yuhang Zhu , Mengna Yang , Weilin Lv , Shijie Guo , Jian S. Dai

{"title":"Lie algebra-based high-order constraint analysis of a novel multi-loop metamorphic mechanism derived from four-bar linkage for lower limb exoskeletons","authors":"Yusong Xing , Jun Wei , Yuhang Zhu , Mengna Yang , Weilin Lv , Shijie Guo , Jian S. Dai","doi":"10.1016/j.mechmachtheory.2025.105994","DOIUrl":"10.1016/j.mechmachtheory.2025.105994","url":null,"abstract":"<div><div>Traditional lower limb exoskeletons are typically designed for fixed postures but struggle to adapt to dynamic, multi-scenario environments. This paper investigates a novel multi-loop metamorphic mechanism for lower limb exoskeletons, enabling smooth posture transitions among walking, sitting, kneeling, and intermediate states to meet variable support requirements. First, a topological structure connecting the lower limbs and support rods is established, and a four-bar linkage-based multi-loop metamorphic mechanism is proposed, achieving configuration changes via link overlap or axis collinearity. Next, first- and second-order kinematic equations are derived using Lie group and Lie algebra exponential products. Singular configurations and motion bifurcation are analyzed through the Jacobian matrix constructed with Lie bracket operations, leading to bifurcation conditions and corresponding motion branch diagrams. Finally, the proposed metamorphic mechanism is implemented in a lower limb exoskeleton, identifying five distinct motion branches, four corresponding to walking, sitting, kneeling, and transitional postures. Joint velocity constraints enable effective branch switching, resolving challenge of increased instantaneous degrees of freedom in singular configurations.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"209 ","pages":"Article 105994"},"PeriodicalIF":4.5,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683057","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

Force-guided heuristic kinematics control of a continuum robot with variable curvatures

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2025-03-22 DOI: 10.1016/j.mechmachtheory.2025.106007

Yuhang Liu, Kai Luo, Qiang Tian, Haiyan Hu

{"title":"Force-guided heuristic kinematics control of a continuum robot with variable curvatures","authors":"Yuhang Liu, Kai Luo, Qiang Tian, Haiyan Hu","doi":"10.1016/j.mechmachtheory.2025.106007","DOIUrl":"10.1016/j.mechmachtheory.2025.106007","url":null,"abstract":"<div><div>Continuum robots, particularly cable-driven continuum robots (CDCRs), have broad application prospects due to their lightweight and flexibility, featuring simple structures and actuation. However, their accurate control relies on high-precision kinematic models with nonuniform curvatures and the associate algorithms of inverse kinematics. In this article, the discrete elastic rod method based on discrete differential geometry is used to establish the variable curvature kinematic model of a CDCR, and a heuristic algorithm of optimal control guided by the virtual constraint forces are proposed to solve inverse kinematics efficiently. A closed-loop trajectory tracking controller based on the proposed algorithm is then designed with high tracking precision. Experimental results demonstrate that the dynamic deviation of the robot's free-end positions from the target ones under the condition of an acceleration 0.3 m/s<sup>2</sup> is only 2.7 % of its total length, and it becomes 6.2 % even when the robot is carrying a payload of 100 g. The control error remains small at a tracking speed of 160 mm/s. Thus, the proposed force-guided heuristic algorithm provides a new way to construct effective dynamic controllers of continuum robots.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"209 ","pages":"Article 106007"},"PeriodicalIF":4.5,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683058","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 digital code based method for configuration analysis and database synthesis of two-mode power-split transmission with three planetary gear sets

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2025-03-22 DOI: 10.1016/j.mechmachtheory.2025.105996

Chen Gong , Huafeng Ding , Andrés Kecskeméthy , Bihai Deng

{"title":"A digital code based method for configuration analysis and database synthesis of two-mode power-split transmission with three planetary gear sets","authors":"Chen Gong , Huafeng Ding , Andrés Kecskeméthy , Bihai Deng","doi":"10.1016/j.mechmachtheory.2025.105996","DOIUrl":"10.1016/j.mechmachtheory.2025.105996","url":null,"abstract":"<div><div>Due to the complexity of the planetary gear train (PGT), it is difficult to design novel configurations of power-split hybrid transmission with three planetary gear sets (PGSs) containing input-split and compound-split two modes. One of the effective solutions is to complete configuration synthesis and establish a complete database of configurations to assist in the design. For this reason, a uniform and simple digital code is proposed to represent the two-mode power-split hybrid transmission configuration, which divides the configuration into PGT and shift element (SE) two parts. The computer only needs to read the digital code to automatically complete the mode analysis, motion characteristics analysis and mechanical interference detection, which are the basis for the configuration synthesis. In addition, to improve design efficiency, while completing the configuration synthesis, the structure and motion characteristics of each configuration are stored in MySQL database, which realizes the fast reading of configuration information. Through this method of assisting configuration design, engineers can quickly search for feasible configurations according to the requirements. Therefore, this method is instructive for the design of power-split hybrid transmission configuration.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"209 ","pages":"Article 105996"},"PeriodicalIF":4.5,"publicationDate":"2025-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683056","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 of an Adjustable Constant Force Mechanism Based on Integrated Magnet-beam Structures and an Adjustable Lever Mechanism

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2025-03-21 DOI: 10.1016/j.mechmachtheory.2025.105997

Yixin Shao , Zhi Wang , Yu Sun , Di Shi , Yanggang Feng , Fei Liu , Xilun Ding , Wuxiang Zhang

{"title":"Design of an Adjustable Constant Force Mechanism Based on Integrated Magnet-beam Structures and an Adjustable Lever Mechanism","authors":"Yixin Shao , Zhi Wang , Yu Sun , Di Shi , Yanggang Feng , Fei Liu , Xilun Ding , Wuxiang Zhang","doi":"10.1016/j.mechmachtheory.2025.105997","DOIUrl":"10.1016/j.mechmachtheory.2025.105997","url":null,"abstract":"<div><div>This paper presents a novel adjustable constant force mechanism (CFM) based on integrated magnet-beam structures and an adjustable lever mechanism. Different from the designs based on the linear stiffness combination method, the proposed CFM is designed via nonlinear stiffness combination, where attractive magnets are used to generate full-stroke nonlinear negative stiffness, and spline-shaped beams are optimized to provide nonlinear positive stiffness. This enables the generation of full-stroke zero stiffness (i.e., constant force), thereby increasing the constant force region. Moreover, the nonlinear stiffness characteristic also enables force fluctuation compensation by adjusting the initial gap between magnets, ensuring a constant output force even in the presence of manufacturing errors. Additionally, by adjusting the lever ratio of the lever mechanism, the constant force magnitude can be adjusted to adapt to different applications. The working principle and mechanical design of the proposed adjustable CFM are introduced. The static model of the spline-shaped beam is developed, and an optimization study is conducted for parameter determination. Finally, a prototype is fabricated and experiments are carried out to verify the effectiveness of the proposed design.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"209 ","pages":"Article 105997"},"PeriodicalIF":4.5,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683055","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

Topology-manifold-based parametric design of dual-spherical-4R chiral origami mechanisms

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2025-03-20 DOI: 10.1016/j.mechmachtheory.2025.105983

Mi Li , Huijuan Feng , Jian S. Dai

{"title":"Topology-manifold-based parametric design of dual-spherical-4R chiral origami mechanisms","authors":"Mi Li , Huijuan Feng , Jian S. Dai","doi":"10.1016/j.mechmachtheory.2025.105983","DOIUrl":"10.1016/j.mechmachtheory.2025.105983","url":null,"abstract":"<div><div>Chiral mechanisms are defined by their mirror-symmetric structural or motion properties, typically exhibiting a helical morphology. These mechanisms excel in folding capabilities, allowing structures to achieve compact configurations, and are characterized by programmable mechanical properties. Additionally, they enable transitions between linear and rotational motion, generating significant interest in their potential applications. Despite this, a systematic design methodology for such mechanisms remains underdeveloped. Topological manifolds provide a critical mathematical framework for describing origami mechanisms with chiral characteristics, forming the foundation for an effective design approach. This paper introduces a parametric design methodology inspired by origami and based on spherical manifolds for creating dual-spherical-4<em>R</em> chiral mechanisms. These mechanisms facilitate transitions among two distinct fully-folded configurations and a fully-deployed configuration. The proposed methodology capitalizes on the unique attributes of spherical manifolds, which operate independently of length scale constraints. It employs a single design parameter to define the dual-spherical-4<em>R</em> chiral mechanisms, enabling the adjustment of 2D planar profiles and 3D motion spaces. Furthermore, this paper investigates the coupling relationship between the design parameters of chiral origami mechanisms and the fully folded polygonal profiles represented by <em>n</em>-polygons. By uncovering the mathematical principles that govern the structural and motion properties of dual-spherical-4<em>R</em> chiral origami mechanisms, the study establishes a clear connection between design parameters and morphological profiles. This framework provides a foundation for developing reconfigurable modular chiral origami robots with diverse motion capabilities.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"209 ","pages":"Article 105983"},"PeriodicalIF":4.5,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683054","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

An analysis of higher-order kinematics formalisms for an innovative surgical parallel robot

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2025-03-20 DOI: 10.1016/j.mechmachtheory.2025.105986

Calin Vaida , Iosif Birlescu , Bogdan Gherman , Daniel Condurache , Damien Chablat , Doina Pisla

{"title":"An analysis of higher-order kinematics formalisms for an innovative surgical parallel robot","authors":"Calin Vaida , Iosif Birlescu , Bogdan Gherman , Daniel Condurache , Damien Chablat , Doina Pisla","doi":"10.1016/j.mechmachtheory.2025.105986","DOIUrl":"10.1016/j.mechmachtheory.2025.105986","url":null,"abstract":"<div><div>The paper presents a novel modular parallel robot for pancreatic surgery and its higher-order kinematics derived based on various formalisms. The classical vector, homogeneous transformation matrices and dual quaternion approaches are studied for the kinematic functions using both classical differentiation and multidual algebra. The algorithms for inverse kinematics for all three studied formalisms are presented for both differentiation and multidual algebra approaches. Furthermore, these algorithms are compared based on numerical stability, execution times and number and type of mathematical functions and operators contained in each algorithm. A statistical analysis shows that there is significant improvement in execution time for the algorithms implemented using multidual algebra, while the numerical stability is appropriate for all algorithms derived based on differentiation and multidual algebra. While the implementation of the kinematic algorithms using multidual algebra shows positive results when benchmarked on a standard PC, further work is required to evaluate the multidual algorithms on hardware/software used for the modular parallel robot command and control.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"209 ","pages":"Article 105986"},"PeriodicalIF":4.5,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143683053","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

A comprehensive mesh stiffness model for heavy-duty spiral bevel gear pair based on design and manufacturing collaboration

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2025-03-20 DOI: 10.1016/j.mechmachtheory.2025.106005

Siyu Chen , Jing Wei , Haibo Wei , Yuxin Tan , Chuanlong Liu

{"title":"A comprehensive mesh stiffness model for heavy-duty spiral bevel gear pair based on design and manufacturing collaboration","authors":"Siyu Chen , Jing Wei , Haibo Wei , Yuxin Tan , Chuanlong Liu","doi":"10.1016/j.mechmachtheory.2025.106005","DOIUrl":"10.1016/j.mechmachtheory.2025.106005","url":null,"abstract":"<div><div>A comprehensive mesh stiffness model (CMSM) for heavy-duty spiral bevel gears (SBGs) was proposed based on design and manufacturing collaboration. First, a collaborative machining configuration model (CMCM) for face-milled SBGs was established based on the spread-blade cutting method (SBCM) and homogeneous coordinate transformation. Subsequently, an improved tooth contact analysis method (ITCAM) that included the unloaded transmission error (UTE) and contact characteristics was proposed with ease-off and elastic theory to compensate for program instability caused by the traditional tooth contact analysis method (TTCAM). Finally, a microsegment beam model containing teeth and a foundation was established using discrete means. The global flexibility matrix model (GFMM) was derived by combining the elastic potential energy principle and the nonlinear Hertz theory, which considers the axial flexibilities and coupling effects. Based on multitooth kinematics theory and the load conservation principle, a CMSM for design and manufacturing cooperation was developed. Using specific examples, the validity of CMSM was verified through comparison with the results of a numerical simulation, which showed that the proposed model can predict the mesh stiffness of SBGs with high accuracy under light or heavy loads.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"209 ","pages":"Article 106005"},"PeriodicalIF":4.5,"publicationDate":"2025-03-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143682696","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

Dynamic modeling of hybrid robots through stiffness directionally releasing and multiple-node dynamics assembling

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2025-03-19 DOI: 10.1016/j.mechmachtheory.2025.106002

Jiajun Zhang , Fugui Xie , Xin-Jun Liu

{"title":"Dynamic modeling of hybrid robots through stiffness directionally releasing and multiple-node dynamics assembling","authors":"Jiajun Zhang , Fugui Xie , Xin-Jun Liu","doi":"10.1016/j.mechmachtheory.2025.106002","DOIUrl":"10.1016/j.mechmachtheory.2025.106002","url":null,"abstract":"<div><div>More and more hybrid robots are being applied in various fields, but researches on their dynamic modeling have not kept pace. The key to modeling hybrid robots lies in assembling of parallel and serial mechanisms, which gives rise to two unresolved problems: 1) modeling of parallel mechanisms with free boundary conditions; and 2) dynamic assembling at multiple nodes between the two mechanisms. To solve them, this paper proposes a dual-node joints modeling method and a multiple-node receptance coupling method respectively. The first method achieves stiffness releasing for any joint by constructing constraint wrench spaces, allowing extraction and elimination of stiffness in the directions of DOF. Then, the dynamics of parallel mechanisms with free boundaries is assembled by the dual-node joints. The second method achieves multiple-node dynamic assembling through partition of receptance matrices and boundary condition analysis. Subsequently, dynamic models of hybrid robots are built. To verify the methods, a hybrid machining robot is presented as an example and modeled. The modal shapes and frequency responses are predicted and compared to the experimental ones, which show high modeling accuracy.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"209 ","pages":"Article 106002"},"PeriodicalIF":4.5,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643151","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

Predictive inverse kinematics with trajectory scaling for redundant manipulators based on quadratic optimization

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2025-03-19 DOI: 10.1016/j.mechmachtheory.2025.105988

Łukasz Woliński, Marek Wojtyra

{"title":"Predictive inverse kinematics with trajectory scaling for redundant manipulators based on quadratic optimization","authors":"Łukasz Woliński, Marek Wojtyra","doi":"10.1016/j.mechmachtheory.2025.105988","DOIUrl":"10.1016/j.mechmachtheory.2025.105988","url":null,"abstract":"<div><div>Redundant robots display unique capabilities, presenting equally unique challenges at the same time. The solution to the inverse kinematics (IK) problem needs to account for a greater number of unknowns (joint variables) than equations. The classic Jacobian pseudoinverse-based methods are well established and often used to solve the IK problems. However, they usually do not support the inclusion of joint position, velocity, and acceleration constraints. On the other hand, the constraints can be easily included when the IK is formulated as an optimization problem. Our method, the PQPIK-S (Predictive Quadratic Programming Inverse Kinematics with Scaling), is based on a quadratic programming formulation and includes trajectory scaling to slow down the desired manipulator motion if no solution satisfying the velocity and acceleration constraints can be found. As an extension over our previous QPIK-S method, the PQPIK-S computes the solution for several future steps inside the prediction window. The PQPIK-S is successfully tested in simulations utilizing a model of the KUKA LWR 4+ 7-DOF manipulator as well as in experiments using a real robot.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"209 ","pages":"Article 105988"},"PeriodicalIF":4.5,"publicationDate":"2025-03-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143643150","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 complete approach for error modeling based on failure of geometrical constraint and kinematic error node (KEN)

IF 4.5 1区工程技术

Mechanism and Machine Theory Pub Date : 2025-03-18 DOI: 10.1016/j.mechmachtheory.2025.105984

Ziyue Li, Weizhong Guo

引用次数: 0