{"title":"A bilateral wrist robotic system with compliant actuation for rehabilitation training","authors":"Zhimin Hou, Yao Tong, Ke Shi, Haoyong Yu","doi":"10.1016/j.mechmachtheory.2025.105937","DOIUrl":"10.1016/j.mechmachtheory.2025.105937","url":null,"abstract":"<div><div>In this article, we present a bilateral wrist robotic system for rehabilitation training that extracts subject-adaptive reference movements from the unaffected limb using a passive module while safely assisting the affected limb using an active module. The system features a parallel mechanism for both modules, supporting three degrees of freedom (DoF) in wrist motion with reduced inertia. The active module employs three linear series elastic actuators (SEAs) to ensure low mechanical impedance and safe interaction. Force and motion tracking controls are implemented in the robot’s end-effector space to enable various bilateral training exercises. Additionally, we introduce a dynamic model for the multi-DoF SEA-driven parallel robot, with a feedforward design compensating for unmodeled nonlinearities. Experimental results validate the system’s performance in transparency, force tracking, and motion tracking. Finally, the bilateral training framework’s effectiveness is demonstrated through two case studies involving healthy subjects with simulated impairments.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"207 ","pages":"Article 105937"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376528","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}
Kai Wu , Shaoxiong Feng , Hengyi An , Giuseppe Carbone , Weihua Li
{"title":"Evaluation of robot kinematic performance under motion constraints in a teleoperated robotic ultrasound system","authors":"Kai Wu , Shaoxiong Feng , Hengyi An , Giuseppe Carbone , Weihua Li","doi":"10.1016/j.mechmachtheory.2025.105952","DOIUrl":"10.1016/j.mechmachtheory.2025.105952","url":null,"abstract":"<div><div>In a teleoperated robotic ultrasound system based on serial robots, a doctor uses a master device to control a slave serial robot for performing ultrasound inspections on patients. To effectively detect organs deep beneath the skin, the robot's motion direction and velocity must be precisely controlled, where the translational or rotational motion is constrained to move separately. During the inspection, the target position and motion velocity need to be continuously synchronized between the master device and the serial robot to ensure optimal coordination. However, the kinematic performance of serial robots is inconsistent across the spatial workspace, leading to issues such as protective stops, velocity fluctuations, and tracking delay errors. This paper proposes an evaluation method for the kinematic performance of serial robots based on the maximum attainable velocity in any direction. An algorithm is described to determine the corresponding maximum achievable translational or rotational velocities when rotational or translational motion is constrained. Experimental results confirm the high accuracy of this algorithm. Consequently, further workspace analysis is conducted to inform the layout and velocity settings of the teleoperated robotic ultrasound system for practical applications.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"207 ","pages":"Article 105952"},"PeriodicalIF":4.5,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143376527","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}
Clark Roubicek, Philip B. Klocke, Davis Wing, Spencer P. Magleby, Larry L. Howell
{"title":"Design and testing of a precision coupling for origami-based arrays","authors":"Clark Roubicek, Philip B. Klocke, Davis Wing, Spencer P. Magleby, Larry L. Howell","doi":"10.1016/j.mechmachtheory.2025.105936","DOIUrl":"10.1016/j.mechmachtheory.2025.105936","url":null,"abstract":"<div><div>Creating ways to achieve precision positioning in large-motion deployable origami-based systems through improving accuracy and repeatability in the deployed state could enable better performance and new applications, such as optics. Precision positioning of origami-based arrays can be a challenge because of the high number of interconnected panels, large motion between stowed and deployed states, and challenge identifying volumes for precision alignment systems given the thin aspect ratio of the panels. This work introduces and tests a design for a precision coupling suitable for origami-based deployable arrays. The coupling is placed in a Z-fold mechanism and in two degree-four vertex (D4V) mechanisms, which are fundamental components of many origami-based arrays. The alignment and repeatability of these mechanisms are tested using a 3D scanner and the best-fit plane. The Z-fold mechanism has a repeatability of about 0.50° and 0.50 mm, and the D4V mechanisms have a repeatability of about 0.15° and 0.50 mm. These values show potential for certain optical applications and demonstrate that precision couplings can be implemented in origami patterns to increase performance of origami-based arrays.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"206 ","pages":"Article 105936"},"PeriodicalIF":4.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143156154","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}
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}