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}
Pub Date : 2024-11-26DOI: 10.1016/j.mechmachtheory.2024.105861
Jinhao Duan , Hanqing Liu , Le Yan , Zhufeng Shao , Zhaokun Zhang , Xiaoqiang Tang , Minjian Huang , Zixiang Peng
Anti-disturbance performance reflects the core performance of cable-driven parallel robots (CDPRs) to resist external wrenches and exert wrenches to the outside world, which plays a significant role in the design and control of CDPRs. However, existing analysis methods encounter the issue of dimensional collapse when analyzing the anti-disturbance performance of redundant CDPRs, thereby failing to reflect the influence of tension distribution. In this paper, the augmented wrench space and Augmented Available Wrench Set (AAWS) are proposed for the analysis and tension distribution of redundant CDPRs, establishing the complete mapping between cable tensions and terminal wrenches of redundant CDPRs. The AAWS resolves the issue of dimensional collapse encountered in existing methods, and clarifies the comprehensive impact of tension distribution on the performance of redundant CDPRs. A tension distribution method is developed based on the AAWS to enhance the anti-disturbance performance of redundant CDPRs. Simulation indicates that the proposed AAWS-based tension distribution method effectively improves the anti-disturbance performance compared to the commonly used 2-norm-based method and the centroid method. This paper presents an efficient and universal approach for analyzing, evaluating, and improving the anti-disturbance performance of redundant CDPRs.
{"title":"Enhancing anti-disturbance performance of redundant cable-driven parallel robots: Analysis and tension distribution method","authors":"Jinhao Duan , Hanqing Liu , Le Yan , Zhufeng Shao , Zhaokun Zhang , Xiaoqiang Tang , Minjian Huang , Zixiang Peng","doi":"10.1016/j.mechmachtheory.2024.105861","DOIUrl":"10.1016/j.mechmachtheory.2024.105861","url":null,"abstract":"<div><div>Anti-disturbance performance reflects the core performance of cable-driven parallel robots (CDPRs) to resist external wrenches and exert wrenches to the outside world, which plays a significant role in the design and control of CDPRs. However, existing analysis methods encounter the issue of dimensional collapse when analyzing the anti-disturbance performance of redundant CDPRs, thereby failing to reflect the influence of tension distribution. In this paper, the augmented wrench space and Augmented Available Wrench Set (AAWS) are proposed for the analysis and tension distribution of redundant CDPRs, establishing the complete mapping between cable tensions and terminal wrenches of redundant CDPRs. The AAWS resolves the issue of dimensional collapse encountered in existing methods, and clarifies the comprehensive impact of tension distribution on the performance of redundant CDPRs. A tension distribution method is developed based on the AAWS to enhance the anti-disturbance performance of redundant CDPRs. Simulation indicates that the proposed AAWS-based tension distribution method effectively improves the anti-disturbance performance compared to the commonly used 2-norm-based method and the centroid method. This paper presents an efficient and universal approach for analyzing, evaluating, and improving the anti-disturbance performance of redundant CDPRs.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105861"},"PeriodicalIF":4.5,"publicationDate":"2024-11-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723656","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 : 2024-11-25DOI: 10.1016/j.mechmachtheory.2024.105860
J. Sanchez-Espiga , M. Fuerst , A. Fernandez-del-Rincon , M. Otto , F. Viadero , K. Stahl
This work presents a study focused on the behaviour of low-speed planetary gear sets with 3 to 7 equally spaced planets affected by their inherent geometrical characteristics. On the one hand, this work identifies the conditions that make the transmission act as fixed, even including floatability in the sun gear, due to their inherent geometrical factors in transmissions with an even number of planets. On the other hand, this work extends the criteria employed to classify the kinds of planetary gearboxes according to their geometry, including the order of the sequence in a sequentially phased transmission. A new expression is proposed in order to take this order into account. Then, several different transmissions are modelled covering the possible configurations. To observe the impact that these aspects have in the transmission’s behaviour the load sharing ratio and the orbits described by the sun gear are extracted. These results confirm the importance of the mentioned sequence order in the behaviour of these transmissions.
{"title":"On the behaviour of n-planets planetary gear sets influenced by geometrical design factors","authors":"J. Sanchez-Espiga , M. Fuerst , A. Fernandez-del-Rincon , M. Otto , F. Viadero , K. Stahl","doi":"10.1016/j.mechmachtheory.2024.105860","DOIUrl":"10.1016/j.mechmachtheory.2024.105860","url":null,"abstract":"<div><div>This work presents a study focused on the behaviour of low-speed planetary gear sets with 3 to 7 equally spaced planets affected by their inherent geometrical characteristics. On the one hand, this work identifies the conditions that make the transmission act as fixed, even including floatability in the sun gear, due to their inherent geometrical factors in transmissions with an even number of planets. On the other hand, this work extends the criteria employed to classify the kinds of planetary gearboxes according to their geometry, including the order of the sequence in a sequentially phased transmission. A new expression is proposed in order to take this order into account. Then, several different transmissions are modelled covering the possible configurations. To observe the impact that these aspects have in the transmission’s behaviour the load sharing ratio and the orbits described by the sun gear are extracted. These results confirm the importance of the mentioned sequence order in the behaviour of these transmissions.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105860"},"PeriodicalIF":4.5,"publicationDate":"2024-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723103","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}
Pub Date : 2024-11-24DOI: 10.1016/j.mechmachtheory.2024.105863
Guangbo Hao
{"title":"Comments on “Design and optimization of a planar anti-buckling compliant rotational joint with a remote center of motion” by R. Chen et al. published in [Mechanism and Machine Theory 203 (2024) 105816]","authors":"Guangbo Hao","doi":"10.1016/j.mechmachtheory.2024.105863","DOIUrl":"10.1016/j.mechmachtheory.2024.105863","url":null,"abstract":"","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105863"},"PeriodicalIF":4.5,"publicationDate":"2024-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723102","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 : 2024-11-23DOI: 10.1016/j.mechmachtheory.2024.105864
Tao Ke , Huafeng Ding , Andrés Kecskemethy
Automatic transmissions (AT) configuration with more pleasant driving and convenient operation have seen increasing attention in the fast-growing automobile industry. This paper presents a new matrix model describing the planetary gear train (PGT) structure, shifting elements layout and clutching sequence of AT configuration. An automatic configuration synthesis method of multi-speed AT is proposed based on this model. Firstly, feasible PGT structures are synthesized by generating corresponding structural matrices subject to structural constraints. Secondly, the shifting elements layouts of each structural matrices are synthesized through distributing brakes and clutches. Thirdly, automatic kinematic analysis of all possible gears is performed to acquire the feasible clutching sequence matrices. Finally, taking the thirteen-speed AT configuration synthesis as an example, the proposed automatic configuration synthesis method was applied to obtain five feasible configurations. Furthermore, the proposed method can automatically synthesize the configuration of other multi-speed AT with multiple planetary gear sets (PGSs) and multiple shifting elements by setting new design constraints.
{"title":"Automatic Synthesis Method for Multi-speed Automatic Transmission Configuration","authors":"Tao Ke , Huafeng Ding , Andrés Kecskemethy","doi":"10.1016/j.mechmachtheory.2024.105864","DOIUrl":"10.1016/j.mechmachtheory.2024.105864","url":null,"abstract":"<div><div>Automatic transmissions (AT) configuration with more pleasant driving and convenient operation have seen increasing attention in the fast-growing automobile industry. This paper presents a new matrix model describing the planetary gear train (PGT) structure, shifting elements layout and clutching sequence of AT configuration. An automatic configuration synthesis method of multi-speed AT is proposed based on this model. Firstly, feasible PGT structures are synthesized by generating corresponding structural matrices subject to structural constraints. Secondly, the shifting elements layouts of each structural matrices are synthesized through distributing brakes and clutches. Thirdly, automatic kinematic analysis of all possible gears is performed to acquire the feasible clutching sequence matrices. Finally, taking the thirteen-speed AT configuration synthesis as an example, the proposed automatic configuration synthesis method was applied to obtain five feasible configurations. Furthermore, the proposed method can automatically synthesize the configuration of other multi-speed AT with multiple planetary gear sets (PGSs) and multiple shifting elements by setting new design constraints.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105864"},"PeriodicalIF":4.5,"publicationDate":"2024-11-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723101","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 : 2024-11-22DOI: 10.1016/j.mechmachtheory.2024.105855
Weiguang Yu , Daokui Qu , Fang Xu , Fengshan Zou , Mingmin Liu , Shichang Liu
Aiming at smoothing discontinuous corners in robotic tool paths, a novel spline named “Composite Trajectory Spline”(CT-Spline) is proposed in this paper. Based on CT-Spline, the real-time position path smoothing for robotic manipulators is realized. CT-Spline enables analytical trajectory planning and interpolation without curve length computation, significantly enhancing trajectory generation efficiency and avoiding numerical errors. By directly controlling resultant trajectory acceleration, CT-Spline avoids decomposing it into tangential and normal accelerations, ensuring adherence to the maximum acceleration constraint while fully utilizing acceleration potential. The geometric shape of CT-Spline is determined by three control points and a trajectory model. This paper further develops C1 and C3 continuous CT-Splines based on two different trajectory models, combined with a velocity look-ahead algorithm to achieve real-time local smoothing of path corners. Additionally, an adaptive control algorithm of smoothing error is introduced to dynamically maximize trajectory velocity. Simulations and experiments validate the effectiveness of CT-Spline, and demonstrate that the proposed C3 continuous trajectory smoothing method has several advantages over the method based on Pythagorean-hodograph splines in terms of kinematic constraints, velocity, smoothing errors, and real-time performance.
{"title":"Real-time position path smoothing for robotic manipulators by constructing Composite Trajectory Spline","authors":"Weiguang Yu , Daokui Qu , Fang Xu , Fengshan Zou , Mingmin Liu , Shichang Liu","doi":"10.1016/j.mechmachtheory.2024.105855","DOIUrl":"10.1016/j.mechmachtheory.2024.105855","url":null,"abstract":"<div><div>Aiming at smoothing discontinuous corners in robotic tool paths, a novel spline named “Composite Trajectory Spline”(CT-Spline) is proposed in this paper. Based on CT-Spline, the real-time position path smoothing for robotic manipulators is realized. CT-Spline enables analytical trajectory planning and interpolation without curve length computation, significantly enhancing trajectory generation efficiency and avoiding numerical errors. By directly controlling resultant trajectory acceleration, CT-Spline avoids decomposing it into tangential and normal accelerations, ensuring adherence to the maximum acceleration constraint while fully utilizing acceleration potential. The geometric shape of CT-Spline is determined by three control points and a trajectory model. This paper further develops C1 and C3 continuous CT-Splines based on two different trajectory models, combined with a velocity look-ahead algorithm to achieve real-time local smoothing of path corners. Additionally, an adaptive control algorithm of smoothing error is introduced to dynamically maximize trajectory velocity. Simulations and experiments validate the effectiveness of CT-Spline, and demonstrate that the proposed C3 continuous trajectory smoothing method has several advantages over the method based on Pythagorean-hodograph splines in terms of kinematic constraints, velocity, smoothing errors, and real-time performance.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105855"},"PeriodicalIF":4.5,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723100","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 : 2024-11-22DOI: 10.1016/j.mechmachtheory.2024.105862
Wei Wang , Yanxun Zhou , Yimin Zhang , Hao Lu
Dynamic performance of ball screw feed system is negatively affected by the vibration and friction, which are mainly related to the contact characteristics of rolling kinematic joints. In this study, starting from clarifying the friction mechanism, a coupling dynamic model of a feed system was developed. The excitation forces and moments are analyzed to investigate the contribution to the vibration characteristics. Based on the coulomb and viscous friction theories, the viscous friction, sliding friction and elastic hysteresis friction are formulated. According to the benefits of the comprehensive model, the vibration responses and friction forces can be obtained by solving the dynamic equations, which avoids the iterative formula of contact loads and angles. Vibration testing experiment is performed to prove the validity. In particular, the effects of excitation force, feeding acceleration and eccentric distance on the vibration and friction characteristics are investigated. Furthermore, the model can supply some theoretical principles to suppress vibration and friction. The study also helps to improve the performance of a ball screw feed system.
{"title":"Dynamic modeling and friction force analysis of ball screw feed system with eccentric load and high acceleration","authors":"Wei Wang , Yanxun Zhou , Yimin Zhang , Hao Lu","doi":"10.1016/j.mechmachtheory.2024.105862","DOIUrl":"10.1016/j.mechmachtheory.2024.105862","url":null,"abstract":"<div><div>Dynamic performance of ball screw feed system is negatively affected by the vibration and friction, which are mainly related to the contact characteristics of rolling kinematic joints. In this study, starting from clarifying the friction mechanism, a coupling dynamic model of a feed system was developed. The excitation forces and moments are analyzed to investigate the contribution to the vibration characteristics. Based on the coulomb and viscous friction theories, the viscous friction, sliding friction and elastic hysteresis friction are formulated. According to the benefits of the comprehensive model, the vibration responses and friction forces can be obtained by solving the dynamic equations, which avoids the iterative formula of contact loads and angles. Vibration testing experiment is performed to prove the validity. In particular, the effects of excitation force, feeding acceleration and eccentric distance on the vibration and friction characteristics are investigated. Furthermore, the model can supply some theoretical principles to suppress vibration and friction. The study also helps to improve the performance of a ball screw feed system.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105862"},"PeriodicalIF":4.5,"publicationDate":"2024-11-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142723099","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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