Xinge Li , Yukun Wang , Ke Wu , Yi Xu , Xunuo Cao , Tao Feng , Tong Chen , Piaopiao Jin , Zhe Wang , Yaoting Xue , Tuck-Whye Wong , Fanghao Zhou , Tiefeng Li
{"title":"Design and modeling of a multi-backbone continuum robot with a large extension ratio","authors":"Xinge Li , Yukun Wang , Ke Wu , Yi Xu , Xunuo Cao , Tao Feng , Tong Chen , Piaopiao Jin , Zhe Wang , Yaoting Xue , Tuck-Whye Wong , Fanghao Zhou , Tiefeng Li","doi":"10.1016/j.mechmachtheory.2025.105935","DOIUrl":"10.1016/j.mechmachtheory.2025.105935","url":null,"abstract":"<div><div>Multi-backbone continuum robots (MBCRs), operated through parallel elastic rods, offer superior compliance compared to rigid robots and improved reliability over tendon-driven continuum robots. Despite their high performance in flexible manipulation, MBCRs have been underutilized on mobile robotic platforms due to packaging constraints. In this work, we present a novel MBCR design with a large extension ratio, comprising two extensible sections connected in series. Each section is equipped with intermediate constraints, providing significant length variability and omnidirectional bending capabilities. To analyze the robot’s kinematics, we develop a modeling approach based on Euler–Bernoulli beam theory and Lagrangian mechanics, enhanced with an optimization-based solution method. To validate our design and model, we construct an MBCR prototype with an extension ratio of 5.0. Both theoretical and experimental validations demonstrate that intermediate constraints significantly expand the workspace of the extensible sections and reduce the compressive force on the rods. Additionally, we evaluate the feasible space of the model and test the robot’s capability in path following, with an average deviation of only 1.3% when tracking a spatial helix path.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"206 ","pages":"Article 105935"},"PeriodicalIF":4.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156487","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}
{"title":"Closed-form forward kinematics of a novel class of 3-RRR spherical parallel mechanisms with coplanar intermediate-joint axes and coplanar distal-joint axes","authors":"Wei Li, Shuai Zhang, Shenghao Dai, Huaijin Ye, Weizhong Guo, Feng Gao","doi":"10.1016/j.mechmachtheory.2025.105930","DOIUrl":"10.1016/j.mechmachtheory.2025.105930","url":null,"abstract":"<div><div>The forward kinematics (FK) of 3-<u>R</u>RR spherical parallel mechanisms (SPMs) has been studied extensively, which is essential for their calibration and control. These studies indicate that most 3-<u>R</u>RR SPMs are associated with octic characteristic equations, which must be solved using iterative approaches. This paper introduces a new class of 3-<u>R</u>RR SPMs featuring simplified FK formulations, characterized by three coplanar intermediate-joint axes and three coplanar distal-joint axes. Unlike most 3-<u>R</u>RR SPMs, this class admits only up to four distinct assembly modes. Moreover, four distinct formulations are proposed, all yielding quartic characteristic equations, thereby enabling closed-form FK solutions. Furthermore, one special subclass of the robot class is found to admit quadratic characteristic equations with simpler coefficient expressions. Beyond simplified FK relations, this robot class also offers unlimited rotation capability about certain directions, making it potentially attractive for practical applications. It is worth noting that this robot class provides flexibility in selecting architecture parameters, thereby allowing for a wide range of designs. Additionally, the proposed formulations can also be applied to certain parallel mechanisms with alternative topologies.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"206 ","pages":"Article 105930"},"PeriodicalIF":4.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156153","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}
Jun Wen , Wenlong Du , Jinbo Hou , Shifeng Rong , Zhenyu Zhou , Qiang Wang , Han Ding
{"title":"Lapping tooth surface micro-topography prediction for extended epicycloid hypoid gears","authors":"Jun Wen , Wenlong Du , Jinbo Hou , Shifeng Rong , Zhenyu Zhou , Qiang Wang , Han Ding","doi":"10.1016/j.mechmachtheory.2025.105931","DOIUrl":"10.1016/j.mechmachtheory.2025.105931","url":null,"abstract":"<div><div>Lapping is a complex precision tooth surface cutting technology for the extended epicycloid hypoid gears, which relies on experienced engineers to obtain ideal machining quality by setting the process parameters reasonably and accurately controlling cutting process. In order to improve the predictability and controllability, influence of different gear parameters on lapping process and geometric topography was systematically studied. Focusing on tooth surface lapping and its micro-topography, an innovative prediction method id proposed. Firstly, the hypoid gear pair model is established, and then height parameters of the tooth surface are calculated by the deduced lapping depth formula. Then, a local tooth surface was reconstructed based on the height parameters by using fast Fourier transform, and prediction model of micro-topography considering the initial topography and random wear mechanism was established. Finally, different lapping parameters considering cutting characteristics of abrasive particles is designed for their influence on tooth surface micro-topography.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"206 ","pages":"Article 105931"},"PeriodicalIF":4.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100803","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}
Shuai Mo , Wenhao Song , Yingxin Zhang , Yuansheng Zhou , Bowei Yao , Haruo Houjoh , Wei Zhang
{"title":"A new iterative method for calculating the time-varying meshing stiffness of orthogonal face gear pairs","authors":"Shuai Mo , Wenhao Song , Yingxin Zhang , Yuansheng Zhou , Bowei Yao , Haruo Houjoh , Wei Zhang","doi":"10.1016/j.mechmachtheory.2025.105938","DOIUrl":"10.1016/j.mechmachtheory.2025.105938","url":null,"abstract":"<div><div>Time-varying meshing stiffness (TVMS) plays a critical part in the dynamic analysis of gear systems. This paper introduces a new iterative method for calculating the TVMS of orthogonal face gear pairs. Initially, the tooth surface equations are derived based on the shaping process. A contact coordinate system for the gear pair is subsequently established. The initial values for the equations are determined through a traversal search method, which facilitates the calculation of contact ellipse parameters and the load distribution function across the tooth surface. Subsequently, the surfaces are further analyzed by slicing along the radial direction and tooth profile. Using the potential energy method, the deflection of an equivalent cantilever beam under working conditions is derived. Load distribution coefficients are iteratively assigned and refined, with the TVMS recalculated until convergence criteria are satisfied. Finally, a case study examines the effects of pressure angle and external loads on the calculated results. The proposed model is validated through finite element analysis, demonstrating its accuracy and reliability.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"206 ","pages":"Article 105938"},"PeriodicalIF":4.5,"publicationDate":"2025-01-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156155","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}
{"title":"Design and configuration switching analysis of a novel 3−P⌢RPS reconfigurable parallel mechanism","authors":"Yili Kuang , Haibo Qu , Xiao Li , Sheng Guo","doi":"10.1016/j.mechmachtheory.2025.105927","DOIUrl":"10.1016/j.mechmachtheory.2025.105927","url":null,"abstract":"<div><div>This paper designed a novel 6-degree-of-freedom reconfigurable parallel mechanism with three configurations based on an origami-inspired base. The reconfigurable base serves as the foundation for connecting a parallel mechanism to form an adaptable and versatile robotic system. Firstly, kinematic performance of the mechanism is analyzed in different configurations, including position and velocity, reachable workspace, and singularity. To investigate the mechanism's configuration switching, we proposed a generative trajectory planning method incorporating an acceleration function. The method is capable of rapidly generating the trajectory of the mechanism with given initial and end positional points and effectively avoiding the singularities. Finally, to quantify reconfigurability performance of the mechanism, a reconfigurability index (RI) derived from foldability is proposed. The mechanism's reconfigurability is analyzed for different position/orientation points with the given initial orientation or position, respectively. The generative trajectory planning method proposed in this paper can be used for intelligent control of the mechanism. The reconfigurability index can be used as an important basis for actuation optimization and performance analysis of reconfigurable mechanisms.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"206 ","pages":"Article 105927"},"PeriodicalIF":4.5,"publicationDate":"2025-01-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156156","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}
{"title":"Position and velocity analyses of the tripod joint with aspherical rollers","authors":"Carlo Innocenti","doi":"10.1016/j.mechmachtheory.2025.105925","DOIUrl":"10.1016/j.mechmachtheory.2025.105925","url":null,"abstract":"<div><div>The paper addresses the kinematics of a type of tripod joint that has seen application over the past two decades in the automotive industry, due to its anti-shudder features. The joint encompasses three rollers externally delimited by axisymmetric non-spherical surfaces. The rollers run on tracks machined on one of the connected shafts. Each roller has a cylindrical inner surface that is in contact, theoretically along a circle, with the spherical ending of a trunnion extending from the other shaft. The paper solves for the first time in polynomial form the position analysis of this type of joint. Then, after pointing out that a tripod joint does not have an instantaneous transmission ratio, the paper addresses the first-order kinematics of the joint. As a further original result, the paper demonstrates that the analyzed tripod joint, when connected in series to a ball non-plunging constant velocity joint, gives rise to a three-shaft driveline which is strictly homokinetic if the axes of the terminal shafts are parallel. Numerical examples show application to case studies of the procedures proposed to solve the position and velocity analyses.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"206 ","pages":"Article 105925"},"PeriodicalIF":4.5,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156152","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}
{"title":"Classification of the three-dimensional persistent POE manifolds of SE(3)","authors":"Marco Carricato","doi":"10.1016/j.mechmachtheory.2025.105926","DOIUrl":"10.1016/j.mechmachtheory.2025.105926","url":null,"abstract":"<div><div>The set of rigid displacements of the end-effector of a mechanism is ordinarily a manifold of the special Euclidean group SE(3). The tangent spaces of the manifold form vector spaces of twists describing the end-effector instantaneous motions. The twist space at any generic pose is often required to be a rigidly-displaced copy of the twist space in the home configuration: when this happens the twist space and the corresponding manifold are called persistent. There are three known families of persistent manifolds of SE(3). The first one comprises the Lie groups of SE(3), for which the twist space is invariant and coincides with a subalgebra of the Lie algebra of SE(3). The second family includes the symmetric spaces of SE(3), for which the twist space is a persistent Lie triple system. The third family is a subset of the product-of-exponential (POE) manifolds, which emerge by the product of two or more Lie groups and naturally describe the motion of serial chains. While the classification of Lie groups and symmetric spaces of SE(3) is state-of-the-art, the classification of persistent POE manifolds is yet to be completed. This paper provides the derivation and classification of persistent POE manifolds of dimension 3.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"206 ","pages":"Article 105926"},"PeriodicalIF":4.5,"publicationDate":"2025-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100772","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}
Hong Guan , Hui Ma , Xi Chen , Qinqin Mu , Yao Zeng , Yanyan Chen , Bangchun Wen , Xumin Guo
{"title":"Nonlinear vibration of rotor-bearing system considering base-motion and bearing-misalignment","authors":"Hong Guan , Hui Ma , Xi Chen , Qinqin Mu , Yao Zeng , Yanyan Chen , Bangchun Wen , Xumin Guo","doi":"10.1016/j.mechmachtheory.2025.105933","DOIUrl":"10.1016/j.mechmachtheory.2025.105933","url":null,"abstract":"<div><div>The rotor system may be subjected to base motion excitation in addition to unbalanced excitation. Moreover, bearing loads can be simultaneously influenced by the base motion and bearing misalignment caused by assembly errors, potentially causing excessive axial load. To study the vibration characteristics of rotors and the contact characteristics of bearings, a new bearing contact force model of the misaligned angular contact ball bearing is proposed and the proposed bearing model is verified by the measured vibration acceleration responses. Incorporating both base motions and bearing misalignment, a dynamic model of a rotor-bearing system is established. The findings reveal that as the rotating speed of the base increases, the amplitude of the variable compliance vibration frequency of the bearing gradually increases because the base motion intensifies the variable compliance vibration of the bearing and some harmonic frequencies and combined frequencies can be observed. Additionally, base motion significantly amplifies the axial force of the bearing, with the axial load rising by approximately 28 times compared to the system without base motion excitation. Both the base motion and bearing misalignment can change the contact zone for the bearing and base motion can cause the ball and raceway to always maintain contact.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"206 ","pages":"Article 105933"},"PeriodicalIF":4.5,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156099","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}
Cuiying Jiang , Decheng Wang , Peng Cheng , Lifang Qiu , Chongxiang Li
{"title":"Optimization design of multi-stable metamaterial origami mechanism (MSMOM) based on graded height and graded conical degree","authors":"Cuiying Jiang , Decheng Wang , Peng Cheng , Lifang Qiu , Chongxiang Li","doi":"10.1016/j.mechmachtheory.2025.105929","DOIUrl":"10.1016/j.mechmachtheory.2025.105929","url":null,"abstract":"<div><div>To investigate the mechanical properties of the multi-stable metamaterial origami mechanism (MSMOM), this paper proposes two novel research parameters. The two parameters are graded initial height and graded conical degree, respectively. MSMOM is composed of cylindrical or conical bistable Kresling units arranged in series. A target optimization model based on the rigid foldable truss method is established. The optimization objectives and constraint conditions related to the proposed two research parameters are determined. Three optimized configurations of MSMOM are obtained through the goal attainment optimization algorithm. The mechanical model based on the nonlinear bar-hinge model is established by MATLAB. The mechanical performance and deformation modes of optimized MSMOMs are explored. A static/quasi-static finite element model is developed based on ABAQUS to validate the nonlinear bar-hinge model. The research findings indicate that the two novel research parameters significantly influence the mechanical performances of MSMOM. Specifically, these influences are evident in force-displacement curves, stability types, snap-through behavior, energy absorption capacity, and deformation modes. It contributes to advancing the development of multi-stable mechanical metamaterials to meet diverse application needs or working scenarios.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"206 ","pages":"Article 105929"},"PeriodicalIF":4.5,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156101","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}
{"title":"Design of a compliant mechanism with collinear input and output","authors":"Mao-Lin Liao , Ngoc Dang Khoa Tran , Dung-An Wang","doi":"10.1016/j.mechmachtheory.2025.105932","DOIUrl":"10.1016/j.mechmachtheory.2025.105932","url":null,"abstract":"<div><div>In this paper, we propose an approach for the topology design of a single-input, double-output (SIDO) compliant mechanism with collinear inputs and outputs. The topology design of the SIDO mechanism is accomplished by superimposing two single-input, single-output (SISO) sub-mechanisms. A kinetostatic model, based on the beam constraint model (BCM), is developed for the SIDO mechanism. Subsequently, dimensional design is applied to the conceptual configurations of the SIDO mechanism using an optimization method. The BCM becomes more efficient and capable of addressing complex displacement analyses by integrating the virtual slider model. Potential applications of the proposed SIDO compliant mechanism include miniature presses and tensile testing machines. The primary contributions of this work are twofold. First, we introduce a topology design approach based on superimposition to generate feasible configurations of SIDO planar compliant mechanisms with collinear inputs and outputs. Second, we integrate virtual sliders into a BCM model to address the challenge of modelling linkage-type compliant mechanisms with multiple outputs.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"206 ","pages":"Article 105932"},"PeriodicalIF":4.5,"publicationDate":"2025-01-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100771","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}