Pub Date : 2024-12-05DOI: 10.1016/j.mechmachtheory.2024.105871
Anand Varadharajan , Pablo López García , Stein Crispel , Dirk Lefeber , Tom Verstraten
Mechanical transmission losses account for a significant portion of energy dissipation in electromechanical actuators. These actuators generally use a combination of high-speed electrical motors with a high-ratio gearbox. For such high-ratio gear transmission, even minor deviations in meshing can lead to substantial power loss. To mitigate this, rollers can be used as redundant elements along with gears. This paper highlights the importance of such redundant rollers that function in tandem with gears to facilitate optimal gear meshing through a specific gearbox design which enables to asses the contribution of rollers and gears individually and in combined manner. The findings reveal that overall, rollers significantly reduce gearbox losses both under no-load and loaded conditions. Especially at high speed and high torque regimes, where the gearbox usually suffers severe losses, the efficiency remains consistently high due to improved meshing.
{"title":"Effect of redundant rollers in planetary gearbox","authors":"Anand Varadharajan , Pablo López García , Stein Crispel , Dirk Lefeber , Tom Verstraten","doi":"10.1016/j.mechmachtheory.2024.105871","DOIUrl":"10.1016/j.mechmachtheory.2024.105871","url":null,"abstract":"<div><div>Mechanical transmission losses account for a significant portion of energy dissipation in electromechanical actuators. These actuators generally use a combination of high-speed electrical motors with a high-ratio gearbox. For such high-ratio gear transmission, even minor deviations in meshing can lead to substantial power loss. To mitigate this, rollers can be used as redundant elements along with gears. This paper highlights the importance of such redundant rollers that function in tandem with gears to facilitate optimal gear meshing through a specific gearbox design which enables to asses the contribution of rollers and gears individually and in combined manner. The findings reveal that overall, rollers significantly reduce gearbox losses both under no-load and loaded conditions. Especially at high speed and high torque regimes, where the gearbox usually suffers severe losses, the efficiency remains consistently high due to improved meshing.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105871"},"PeriodicalIF":4.5,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166259","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}
This paper presents a methodology for the design and control of Parallel Kinematic Robots (PKRs). First, one focuses on the problematics of design. In particular, given a parallel mechanism defined by its design parameters and its kinematic modeling as well as its prescribed workspace, the idea is to certify the absence of any numerical instabilities (computational and physical singularities) that may jeopardize the integrity of the robot. This is achieved through two complementary approaches: a global method using symbolic computation and a local one based on continuation techniques and interval calculus, accounting for uncertainties in the design. The methodology is then applied to real PKR examples. Secondly, the paper proposes a control strategy that limits the active joint velocities to ensure the robot remains within its certified workspace. It will be applied to a special class of parallel robots: Spherical Parallel Manipulators (SPM) with coaxial input shafts (CoSPM).
{"title":"Certified kinematic tools for the design and control of parallel robots","authors":"Alexandre Lê , Fabrice Rouillier , Guillaume Rance , Damien Chablat","doi":"10.1016/j.mechmachtheory.2024.105865","DOIUrl":"10.1016/j.mechmachtheory.2024.105865","url":null,"abstract":"<div><div>This paper presents a methodology for the design and control of Parallel Kinematic Robots (PKRs). First, one focuses on the problematics of design. In particular, given a parallel mechanism defined by its design parameters and its kinematic modeling as well as its prescribed workspace, the idea is to certify the absence of any numerical instabilities (computational and physical singularities) that may jeopardize the integrity of the robot. This is achieved through two complementary approaches: a global method using symbolic computation and a local one based on continuation techniques and interval calculus, accounting for uncertainties in the design. The methodology is then applied to real PKR examples. Secondly, the paper proposes a control strategy that limits the active joint velocities to ensure the robot remains within its certified workspace. It will be applied to a special class of parallel robots: Spherical Parallel Manipulators (SPM) with coaxial input shafts (CoSPM).</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105865"},"PeriodicalIF":4.5,"publicationDate":"2024-12-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166256","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}
Pub Date : 2024-12-04DOI: 10.1016/j.mechmachtheory.2024.105869
Ruiyu Bai , Nan Yang , Zhiwei Qiu , Shane Johnson , Ke Wu , Bo Li , Guimin Chen
Compliant constant-torque mechanisms (CCTMs) maintain constant-torque without the need for complex closed-loop feedback systems, broadening their applications in rehabilitation devices, surgical tools, and cooperative robotic arms. However, CCTMs present considerable design challenges due to the pronounced nonlinearities that arise due to large deflections and multi-axial loadings. Traditional CCTM design strategies focus on managing post-buckling phenomena, often leading to increased stresses and an imbalance in positive and negative stiffness, compromising torque consistency and stroke capacity. This study introduces a novel CCTM that effectively decouples the multi-axial loadings and releases axial forces, isolating beam bending forces. This decoupling is achieved by incorporating a parallel-guided compliant mechanism at the fixed end of the beam, which reduces stress and enhances torque stability throughout the operational range. Through the partical swarm optimization of geometric design parameters using the chained beam constraint model, this research has produced a CCTM capable of maintaining torque fluctuations below 0.39% over a rotational range of 18° to 68°. Experimental validations confirm the design’s superiority in providing an extended constant torque stroke and improved consistency, distinguishing it from conventional straight-beam CCTMs.
{"title":"Achieving high-quality and large-stroke constant torque by axial force release","authors":"Ruiyu Bai , Nan Yang , Zhiwei Qiu , Shane Johnson , Ke Wu , Bo Li , Guimin Chen","doi":"10.1016/j.mechmachtheory.2024.105869","DOIUrl":"10.1016/j.mechmachtheory.2024.105869","url":null,"abstract":"<div><div>Compliant constant-torque mechanisms (CCTMs) maintain constant-torque without the need for complex closed-loop feedback systems, broadening their applications in rehabilitation devices, surgical tools, and cooperative robotic arms. However, CCTMs present considerable design challenges due to the pronounced nonlinearities that arise due to large deflections and multi-axial loadings. Traditional CCTM design strategies focus on managing post-buckling phenomena, often leading to increased stresses and an imbalance in positive and negative stiffness, compromising torque consistency and stroke capacity. This study introduces a novel CCTM that effectively decouples the multi-axial loadings and releases axial forces, isolating beam bending forces. This decoupling is achieved by incorporating a parallel-guided compliant mechanism at the fixed end of the beam, which reduces stress and enhances torque stability throughout the operational range. Through the partical swarm optimization of geometric design parameters using the chained beam constraint model, this research has produced a CCTM capable of maintaining torque fluctuations below 0.39% over a rotational range of 18° to 68°. Experimental validations confirm the design’s superiority in providing an extended constant torque stroke and improved consistency, distinguishing it from conventional straight-beam CCTMs.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105869"},"PeriodicalIF":4.5,"publicationDate":"2024-12-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166258","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}
Pub Date : 2024-12-03DOI: 10.1016/j.mechmachtheory.2024.105833
Zhibin Song , Yuanhao Zhang , Yifan Wu , Shiyu Li , Lixuan Zhao , Hongyu Cao , Rongjie Kang , Liwei Shi , Jian S. Dai
The majority of underwater vehicles currently use screw propellers as propulsion method. Despite screw propellers are being promoted to increase the efficiency through better designs and technologies, the circumferential flow caused by the rotation of screw propeller results in wasted energy. This paper proposes an ideal reciprocating straight propulsion paradigm that eliminates this waste by implementing straight backward thrust based on a foldable mechanism. This mechanism can implement a maximized propulsion during the propelling stroke and a minimized resistance during recovery by folding and unfolding the mechanism, which can be adjusted passively via the relative motion between the thruster mechanism and water avoiding using sensors and actuations. This principle makes the reciprocating straight propulsion simple and reliable to be achieved in practice. Besides, a modularized propulsion system with four identical independently thrusters based on the proposed mechanism was proposed, achieving various motion modes in underwater vehicles. The proposed propulsion mechanism was theoretically analyzed and verified through simulations and prototype tests. In mooring tests, the thrust provided by the proposed mechanism is similar to the simulation results. The propulsion performance indicator of an underwater vehicle with the proposed propulsor reached 66 %. The mechanism could turn even with one-sided propulsion.
{"title":"A new reciprocating straight propulsion for high propulsive hydrodynamic efficiency","authors":"Zhibin Song , Yuanhao Zhang , Yifan Wu , Shiyu Li , Lixuan Zhao , Hongyu Cao , Rongjie Kang , Liwei Shi , Jian S. Dai","doi":"10.1016/j.mechmachtheory.2024.105833","DOIUrl":"10.1016/j.mechmachtheory.2024.105833","url":null,"abstract":"<div><div>The majority of underwater vehicles currently use screw propellers as propulsion method. Despite screw propellers are being promoted to increase the efficiency through better designs and technologies, the circumferential flow caused by the rotation of screw propeller results in wasted energy. This paper proposes an ideal reciprocating straight propulsion paradigm that eliminates this waste by implementing straight backward thrust based on a foldable mechanism. This mechanism can implement a maximized propulsion during the propelling stroke and a minimized resistance during recovery by folding and unfolding the mechanism, which can be adjusted passively via the relative motion between the thruster mechanism and water avoiding using sensors and actuations. This principle makes the reciprocating straight propulsion simple and reliable to be achieved in practice. Besides, a modularized propulsion system with four identical independently thrusters based on the proposed mechanism was proposed, achieving various motion modes in underwater vehicles. The proposed propulsion mechanism was theoretically analyzed and verified through simulations and prototype tests. In mooring tests, the thrust provided by the proposed mechanism is similar to the simulation results. The propulsion performance indicator of an underwater vehicle with the proposed propulsor reached 66 %. The mechanism could turn even with one-sided propulsion.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105833"},"PeriodicalIF":4.5,"publicationDate":"2024-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142759066","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}
Pub Date : 2024-11-30DOI: 10.1016/j.mechmachtheory.2024.105866
Vivek Soni, Anand Vaz
A bond graph model for the kinematics and kinetics of a knee assistance exoskeleton for sit-to-stand (SiTSt) or stand-to-sit (StTSi) motions is presented. The exoskeleton is actuated by a wire rope connected to a lead screw and slider nut assembly driven by an electric motor. An energy storage spring (ESS) is used for energy storage and regeneration. The ESS and wire rope apply opposite forces on the slider nut resulting in switching of contact surfaces. The kinematics of the lead screw and slider nut assembly is discussed and a bond graph model for the same is developed considering switching of contact surfaces and friction. Kinetics equations are derived from the model and verified by free body diagram (FBD) analysis. The efficacy of the developed model is demonstrated through simulations, where the switching and effects of friction are captured elegantly. Further, mechanics of wrapping is discussed considering the friction between the wire rope and the pulley. Finally, the bond graph model of the proposed exoskeleton is developed. Simulations are carried out by varying the stiffness of ESS and friction coefficients. A reduction in the assistance motor torque, power and energy requirements due to ESS and wrapping is demonstrated.
{"title":"Kinematics and kinetics of a knee assistance exoskeleton for sit-to-stand and stand-to-sit motions with energy storage and regeneration: A bond graph approach","authors":"Vivek Soni, Anand Vaz","doi":"10.1016/j.mechmachtheory.2024.105866","DOIUrl":"10.1016/j.mechmachtheory.2024.105866","url":null,"abstract":"<div><div>A bond graph model for the kinematics and kinetics of a knee assistance exoskeleton for sit-to-stand (SiTSt) or stand-to-sit (StTSi) motions is presented. The exoskeleton is actuated by a wire rope connected to a lead screw and slider nut assembly driven by an electric motor. An energy storage spring (ESS) is used for energy storage and regeneration. The ESS and wire rope apply opposite forces on the slider nut resulting in switching of contact surfaces. The kinematics of the lead screw and slider nut assembly is discussed and a bond graph model for the same is developed considering switching of contact surfaces and friction. Kinetics equations are derived from the model and verified by free body diagram (FBD) analysis. The efficacy of the developed model is demonstrated through simulations, where the switching and effects of friction are captured elegantly. Further, mechanics of wrapping is discussed considering the friction between the wire rope and the pulley. Finally, the bond graph model of the proposed exoskeleton is developed. Simulations are carried out by varying the stiffness of ESS and friction coefficients. A reduction in the assistance motor torque, power and energy requirements due to ESS and wrapping is demonstrated.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105866"},"PeriodicalIF":4.5,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746387","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}
Pub Date : 2024-11-30DOI: 10.1016/j.mechmachtheory.2024.105854
S. Portron, Pedro M.T. Marques
Geared transmission systems operate under increasingly severe conditions that tend to promote micropitting on the gear flanks. Micropitting leads to an increased local coefficient of friction, in particular due to an increase in the average roughness of the damaged surfaces. Micropitting is hard to predict, but also hard to detect, since it mainly affects the contact conditions, which affect friction forces. On global signals such as input/output torque, these friction forces are one to two orders of magnitude lower than the normal forces and tend not to be detectable due to the noise in the experimental setup. This paper aims at studying the effect of micropitting on the vibrational levels of a geared system, by coupling the gear dynamics model developed by Osman and Velex with the roughness-dependent coefficient of friction formulation from Xu et al., and by representing micropitting by a local increase of the composite roughness. The simulations show that micropitting has a clear impact on the system dynamic behaviour, especially in the direction perpendicular to the plane of contact. Finally, it was shown that the bearing forces and the pinion acceleration are suitable candidates for micropitting detection, even with noisy signals.
{"title":"A model to study the effect of micropitting on the dynamic behaviour of a geared system","authors":"S. Portron, Pedro M.T. Marques","doi":"10.1016/j.mechmachtheory.2024.105854","DOIUrl":"10.1016/j.mechmachtheory.2024.105854","url":null,"abstract":"<div><div>Geared transmission systems operate under increasingly severe conditions that tend to promote micropitting on the gear flanks. Micropitting leads to an increased local coefficient of friction, in particular due to an increase in the average roughness of the damaged surfaces. Micropitting is hard to predict, but also hard to detect, since it mainly affects the contact conditions, which affect friction forces. On global signals such as input/output torque, these friction forces are one to two orders of magnitude lower than the normal forces and tend not to be detectable due to the noise in the experimental setup. This paper aims at studying the effect of micropitting on the vibrational levels of a geared system, by coupling the gear dynamics model developed by Osman and Velex with the roughness-dependent coefficient of friction formulation from Xu et al., and by representing micropitting by a local increase of the composite roughness. The simulations show that micropitting has a clear impact on the system dynamic behaviour, especially in the direction perpendicular to the plane of contact. Finally, it was shown that the bearing forces and the pinion acceleration are suitable candidates for micropitting detection, even with noisy signals.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105854"},"PeriodicalIF":4.5,"publicationDate":"2024-11-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746386","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}
Pub Date : 2024-11-28DOI: 10.1016/j.mechmachtheory.2024.105858
Buşra Aktaş
This study aims to investigate the algebraic forms of the constraint manifolds of and planar and spherical closed chains in Lorentzian space. For this purpose, firstly, the structure equations of closed chains are obtained by using the structure equations of planar and spherical open chains in Lorentzian space. Then, using these equations, the algebraic forms of the constraint manifolds of and planar and spherical closed chains in spacelike and timelike mechanisms are constructed and it is shown which curves these manifolds correspond to.
{"title":"On constraint manifolds of planar and spherical mechanisms in Lorentzian space","authors":"Buşra Aktaş","doi":"10.1016/j.mechmachtheory.2024.105858","DOIUrl":"10.1016/j.mechmachtheory.2024.105858","url":null,"abstract":"<div><div>This study aims to investigate the algebraic forms of the constraint manifolds of <span><math><mrow><mn>4</mn><mi>R</mi></mrow></math></span> and <span><math><mrow><mn>6</mn><mi>R</mi></mrow></math></span> planar and spherical closed chains in Lorentzian space. For this purpose, firstly, the structure equations of closed chains are obtained by using the structure equations of planar and spherical open chains in Lorentzian space. Then, using these equations, the algebraic forms of the constraint manifolds of <span><math><mrow><mn>4</mn><mi>R</mi></mrow></math></span> and <span><math><mrow><mn>6</mn><mi>R</mi></mrow></math></span> planar and spherical closed chains in spacelike and timelike mechanisms are constructed and it is shown which curves these manifolds correspond to.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105858"},"PeriodicalIF":4.5,"publicationDate":"2024-11-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142746385","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}
Pub Date : 2024-11-27DOI: 10.1016/j.mechmachtheory.2024.105835
Zeeshan Qaiser , Shane Johnson , Tanzeel ur Rehman , Bi Shun , Ying Zhou
An adjustable constant force environment is critical in engineering applications, including precision manipulation, surgical robots, and advanced manufacturing, all requiring a wider range of force regulation and adjustment. Traditional adjustable constant force mechanisms (ACFMs) have significant limitations in achieving a wide range of constant force (CF) adjustments due to factors like stress and interference. Existing ACFMs typically offer only a 2–4 times change in CF, which is insufficient. This research aims to provide an order-of-magnitude increase in CF adjustment range while remaining compact and preserving CF quality through section optimization. An analytical model demonstrates the efficacy of adjusting CF by an order-of-magnitude in prismatic and non-prismatic beams for CF adjustment method selection. Additionally, finite element analysis and design optimization of the non-prismatic serpentine beam with an out-of-plumbness imperfection angle and polynomial section description were conducted to maximize CF adjustability and quality. Experimental validation showed a 38 times change in CF adjustability for 5 percent variation in the CF, 18 times improvement in compactness, and high Energy Similarity Index compared to the prismatic benchmark mechanism. This proposed system may be implemented in several applications, including load control, impact and vibration mitigation, space exercise, wearables, etc.
{"title":"Order-of-magnitude increased range of constant force adjustment via section optimization","authors":"Zeeshan Qaiser , Shane Johnson , Tanzeel ur Rehman , Bi Shun , Ying Zhou","doi":"10.1016/j.mechmachtheory.2024.105835","DOIUrl":"10.1016/j.mechmachtheory.2024.105835","url":null,"abstract":"<div><div>An adjustable constant force environment is critical in engineering applications, including precision manipulation, surgical robots, and advanced manufacturing, all requiring a wider range of force regulation and adjustment. Traditional adjustable constant force mechanisms (ACFMs) have significant limitations in achieving a wide range of constant force (CF) adjustments due to factors like stress and interference. Existing ACFMs typically offer only a 2–4 times change in CF, which is insufficient. This research aims to provide an order-of-magnitude increase in CF adjustment range while remaining compact and preserving CF quality through section optimization. An analytical model demonstrates the efficacy of adjusting CF by an order-of-magnitude in prismatic and non-prismatic beams for CF adjustment method selection. Additionally, finite element analysis and design optimization of the non-prismatic serpentine beam with an out-of-plumbness imperfection angle and polynomial section description were conducted to maximize CF adjustability and quality. Experimental validation showed a 38 times change in CF adjustability for 5 percent variation in the CF, 18 times improvement in compactness, and high Energy Similarity Index <span><math><msub><mrow><mi>S</mi></mrow><mrow><mi>C</mi><mi>F</mi></mrow></msub></math></span> compared to the prismatic benchmark mechanism. This proposed system may be implemented in several applications, including load control, impact and vibration mitigation, space exercise, wearables, etc.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105835"},"PeriodicalIF":4.5,"publicationDate":"2024-11-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723659","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}
Pub Date : 2024-11-26DOI: 10.1016/j.mechmachtheory.2024.105852
Ziqiang Zhang , Tianyu Kang , Wenjun Yan , Zhenyun Shi , Zhi Wang , Ye Lu
Most manipulators require extensive operational space; however, in environments where space is limited, these devices must be compact during periods of inactivity. To address this challenge, a redundant rigid-flexible coupling deployable manipulator has been developed that optimizes space utilization and enhances operational capabilities. This development is informed by a detailed examination of the structure and motion performance of the Kresling origami unit. Equivalence principles for the mechanism are proposed, and an optimal rigid-flexible coupling equivalent mechanism unit is selected by integrating motion feasibility analysis with the significance of flexible structures. A 3RUU mechanism unit is chosen, and six such units are serially connected to construct a deployable manipulator. The workspace and mechanical properties of the manipulator are characterized, and principles for implementing reach-point motion are proposed to ensure superior overall performance. Experimental results show that the designed manipulator achieves a folding ratio of 2.58, supports a maximum load of 2611.1 g, and exhibits high flexibility and excellent overall performance in reach-point motion. These findings provide a solid foundation for the broader application of this type of manipulator.
大多数机械手都需要很大的操作空间；然而，在空间有限的环境中，这些设备在闲置期间必须保持紧凑。为了应对这一挑战，我们开发了一种冗余刚柔耦合可部署机械手，它能优化空间利用率并增强操作能力。我们对克瑞斯林折纸装置的结构和运动性能进行了详细研究，并以此为基础进行了开发。提出了该机构的等效原理，并通过将运动可行性分析与柔性结构的重要性相结合，选择了最佳的刚柔耦合等效机构单元。选择了一个 3RUU 机构单元，并将六个这样的单元串联起来，构建了一个可展开的机械手。对机械手的工作空间和机械性能进行了表征，并提出了实现到达点运动的原则，以确保卓越的整体性能。实验结果表明，所设计的机械手实现了 2.58 的折叠率，支持 2611.1 g 的最大载荷，并在触点运动中表现出高度灵活性和卓越的整体性能。这些研究结果为这种机械手的广泛应用奠定了坚实的基础。
{"title":"Design and analysis of an origami-inspired redundant rigid-flexible coupling deployable manipulator","authors":"Ziqiang Zhang , Tianyu Kang , Wenjun Yan , Zhenyun Shi , Zhi Wang , Ye Lu","doi":"10.1016/j.mechmachtheory.2024.105852","DOIUrl":"10.1016/j.mechmachtheory.2024.105852","url":null,"abstract":"<div><div>Most manipulators require extensive operational space; however, in environments where space is limited, these devices must be compact during periods of inactivity. To address this challenge, a redundant rigid-flexible coupling deployable manipulator has been developed that optimizes space utilization and enhances operational capabilities. This development is informed by a detailed examination of the structure and motion performance of the Kresling origami unit. Equivalence principles for the mechanism are proposed, and an optimal rigid-flexible coupling equivalent mechanism unit is selected by integrating motion feasibility analysis with the significance of flexible structures. A 3RUU mechanism unit is chosen, and six such units are serially connected to construct a deployable manipulator. The workspace and mechanical properties of the manipulator are characterized, and principles for implementing reach-point motion are proposed to ensure superior overall performance. Experimental results show that the designed manipulator achieves a folding ratio of 2.58, supports a maximum load of 2611.1 g, and exhibits high flexibility and excellent overall performance in reach-point motion. These findings provide a solid foundation for the broader application of this type of manipulator.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105852"},"PeriodicalIF":4.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723657","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}
Pub Date : 2024-11-26DOI: 10.1016/j.mechmachtheory.2024.105859
Hui Yang, Hong Liu, Liang Zeng, Jianxu Wu, Yan-an Yao
This study proposes an octopod platform with a reconfigurable trunk to enhance walking patterns and terrain adaptability in closed-chain-legged systems. An 8R reconfigurable mechanism generates various gaits, classified into wide and narrow categories based on platform width. These include straight-line walking, zero-radius turning, pitching climbing, and folding rolling gaits, totaling eight configurations. Posture control and width switching are achieved through gait changes. Kinematic models analyze motion singularities and motion strategies are established. A probabilistic model evaluates obstacle climbing proficiency. Dynamic simulations and prototype validation assess walking speed, climbing, and mobility in pipeline terrains. Platform stability on slopes is quantitatively analyzed, as are capabilities within pipeline environments. The study confirms that a reconfigurable trunk improves adaptability to various gaits and terrains in closed-chain-legged platforms.
{"title":"Design and analysis of a novel octopod platform with spatial 8R reconfigurable trunk","authors":"Hui Yang, Hong Liu, Liang Zeng, Jianxu Wu, Yan-an Yao","doi":"10.1016/j.mechmachtheory.2024.105859","DOIUrl":"10.1016/j.mechmachtheory.2024.105859","url":null,"abstract":"<div><div>This study proposes an octopod platform with a reconfigurable trunk to enhance walking patterns and terrain adaptability in closed-chain-legged systems. An 8R reconfigurable mechanism generates various gaits, classified into wide and narrow categories based on platform width. These include straight-line walking, zero-radius turning, pitching climbing, and folding rolling gaits, totaling eight configurations. Posture control and width switching are achieved through gait changes. Kinematic models analyze motion singularities and motion strategies are established. A probabilistic model evaluates obstacle climbing proficiency. Dynamic simulations and prototype validation assess walking speed, climbing, and mobility in pipeline terrains. Platform stability on slopes is quantitatively analyzed, as are capabilities within pipeline environments. The study confirms that a reconfigurable trunk improves adaptability to various gaits and terrains in closed-chain-legged platforms.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105859"},"PeriodicalIF":4.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723658","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}
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