Pub Date : 2024-09-09DOI: 10.1016/j.mechmachtheory.2024.105782
Shaoping Bai
In this work, mechanisms that admit efficient kinematic computations are studied. The computationally efficient mechanisms are a special class of linkages that their constraint equations contain lower-order terms than that of the ordinary linkages. The lower-order constraint equations are of low computational complexity and thus readily solved. In the paper, case studies are carried out for mechanisms up to 3 degrees of freedom (DOF) and some interesting kinematic results are revealed. Examples of computationally efficient mechanisms are also presented.
{"title":"Kinematics of computationally efficient mechanisms","authors":"Shaoping Bai","doi":"10.1016/j.mechmachtheory.2024.105782","DOIUrl":"10.1016/j.mechmachtheory.2024.105782","url":null,"abstract":"<div><p>In this work, mechanisms that admit efficient kinematic computations are studied. The computationally efficient mechanisms are a special class of linkages that their constraint equations contain lower-order terms than that of the ordinary linkages. The lower-order constraint equations are of low computational complexity and thus readily solved. In the paper, case studies are carried out for mechanisms up to 3 degrees of freedom (DOF) and some interesting kinematic results are revealed. Examples of computationally efficient mechanisms are also presented.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"203 ","pages":"Article 105782"},"PeriodicalIF":4.5,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0094114X2400209X/pdfft?md5=fa5931f7c93414d2e33966b82841f29f&pid=1-s2.0-S0094114X2400209X-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142158279","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 : 2024-09-03DOI: 10.1016/j.mechmachtheory.2024.105780
G. Lanaspeze, B. Guilbert, L. Manin, F. Ville
Intense competition between top-level track cycling athletes rEq.uires research to make optimisation possible. In this context, the energetic efficiency of roller chain drives is studied to improve understanding of loss sources and to propose improvements. Losses in chain drives are mainly caused by the meshing/un-meshing process of chain links on the sprockets. However, a preliminary study shows that losses caused by the motion of rollers along their associated tooth profile have a significant influence. The aim of this paper is therefore to explore this phenomenon. An original 2D quasi static model of a two-sprocket drive is presented. The global drive kinematics (including transmission error) is determined using specific sub-models for the tight and slack strands. A local sprocket sub-model is then introduced to calculate link tension, roller/sprocket contact force and roller location. This model can be used for different tooth profile geometries. Based on the results provided by the global and local model, the presented model calculates drive efficiency, considering the losses caused by meshing and roller motion. A comparison with literature is done to ensure the model validity.
{"title":"Quasi-static chain drive model for efficiency calculation - Application to track cycling","authors":"G. Lanaspeze, B. Guilbert, L. Manin, F. Ville","doi":"10.1016/j.mechmachtheory.2024.105780","DOIUrl":"10.1016/j.mechmachtheory.2024.105780","url":null,"abstract":"<div><p>Intense competition between top-level track cycling athletes rEq.uires research to make optimisation possible. In this context, the energetic efficiency of roller chain drives is studied to improve understanding of loss sources and to propose improvements. Losses in chain drives are mainly caused by the meshing/un-meshing process of chain links on the sprockets. However, a preliminary study shows that losses caused by the motion of rollers along their associated tooth profile have a significant influence. The aim of this paper is therefore to explore this phenomenon. An original 2D quasi static model of a two-sprocket drive is presented. The global drive kinematics (including transmission error) is determined using specific sub-models for the tight and slack strands. A local sprocket sub-model is then introduced to calculate link tension, roller/sprocket contact force and roller location. This model can be used for different tooth profile geometries. Based on the results provided by the global and local model, the presented model calculates drive efficiency, considering the losses caused by meshing and roller motion. A comparison with literature is done to ensure the model validity.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"203 ","pages":"Article 105780"},"PeriodicalIF":4.5,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0094114X24002076/pdfft?md5=a911b2d5aff7df6105283299c4218147&pid=1-s2.0-S0094114X24002076-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142128441","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 : 2024-09-02DOI: 10.1016/j.mechmachtheory.2024.105779
Pongsiri Kuresangsai, Matthew O.T. Cole, Guangbo Hao
Flexure-jointed grippers provide compliant grasping capability, have low-cost and flexible manufacturing, and are insusceptible to joint friction and wear. However, their grasp stiffness can be limited by flexure compliance such that loss-of-grasp is prone to occur for high object loads. This paper examines the application of inverted-flexure joints in a cable-driven gripper that can avoid flexure buckling and greatly enhance grasp stiffness and stability. To analyze behavior, an energy-based kinetostatic model is developed for a benchmark grasping problem and validated by hardware experiments. A multi-objective design optimization study is conducted, considering key metrics of peak flexure stress, grasp stiffness, and cable actuation force. Results show that the inverted-flexure design has significantly higher grasp stiffness (63% higher in a targeted design optimization) and requires lower actuation forces (¿20% lower in all optimization cases), compared with equivalent direct-flexure designs. An application study is conducted to validate the predicted operating performance under gravity loading of the grasped object. The results demonstrate that stable and high stiffness grasping can be achieved, even under overload conditions that lead to loss-of-grasp for conventional direct-flexure designs.
{"title":"Analysis and design optimization of a compliant robotic gripper mechanism with inverted flexure joints","authors":"Pongsiri Kuresangsai, Matthew O.T. Cole, Guangbo Hao","doi":"10.1016/j.mechmachtheory.2024.105779","DOIUrl":"10.1016/j.mechmachtheory.2024.105779","url":null,"abstract":"<div><p>Flexure-jointed grippers provide compliant grasping capability, have low-cost and flexible manufacturing, and are insusceptible to joint friction and wear. However, their grasp stiffness can be limited by flexure compliance such that loss-of-grasp is prone to occur for high object loads. This paper examines the application of inverted-flexure joints in a cable-driven gripper that can avoid flexure buckling and greatly enhance grasp stiffness and stability. To analyze behavior, an energy-based kinetostatic model is developed for a benchmark grasping problem and validated by hardware experiments. A multi-objective design optimization study is conducted, considering key metrics of peak flexure stress, grasp stiffness, and cable actuation force. Results show that the inverted-flexure design has significantly higher grasp stiffness (63% higher in a targeted design optimization) and requires lower actuation forces (¿20% lower in all optimization cases), compared with equivalent direct-flexure designs. An application study is conducted to validate the predicted operating performance under gravity loading of the grasped object. The results demonstrate that stable and high stiffness grasping can be achieved, even under overload conditions that lead to loss-of-grasp for conventional direct-flexure designs.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"202 ","pages":"Article 105779"},"PeriodicalIF":4.5,"publicationDate":"2024-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142122620","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 : 2024-09-01DOI: 10.1016/j.mechmachtheory.2024.105775
Wenjie Ju , Jingfu Zhao , Wenjie Zhang , Shiyu Li , Rongjie Kang , Jian S. Dai , Zhibin Song
Series elastic actuators with increasing nonlinear stiffness(NlSEA) have promising applications in human-machine interactions for the existence of a nonlinear elastic mechanism that supplies inherent safety and can implement high torque resolution under low load and quick dynamic response under high load. In this study, a novel design method for a nonlinear elastic mechanism that can be applied in NlSEA is proposed. By combining the S-shaped cantilever beam and specialized cam surface, this study proposed an analytical approach to design a nonlinear elastic mechanism satisfying a given stiffening torque-deformation relationship. The geometric parameters constraints were discussed to support parameter determination. Two kinds of cases of nonlinear elastic mechanisms with increasing and constant stiffness characteristics were conducted to verify the effectiveness and generalizability of the proposed design method by simulations. Moreover, a nonlinear elastic mechanism with an increasing stiffness characteristic was designed and a prototype was fabricated. A torque-deformation verification experiment, regulation response experiments, and sinusoidal tracking experiments were conducted to verify the accuracy, response performance, and tracking performance of the prototype. The designed nonlinear elastic mechanism has a large torque-to-mass ratio in a compact and lightweight structure.
具有增大非线性刚度的串联弹性致动器(NlSEA)在人机交互中具有广阔的应用前景,因为它是一种非线性弹性机构,具有固有的安全性,并能在低负载下实现高扭矩分辨率,在高负载下实现快速动态响应。本研究提出了一种可应用于 NlSEA 的新型非线性弹性机构设计方法。通过结合 S 形悬臂梁和专用凸轮表面,本研究提出了一种分析方法来设计满足给定刚化扭矩-变形关系的非线性弹性机构。讨论了几何参数约束,以支持参数确定。通过仿真验证了所提设计方法的有效性和普适性。此外,还设计了一种刚度特性递增的非线性弹性机构,并制作了原型。为了验证原型的精度、响应性能和跟踪性能,还进行了扭矩变形验证实验、调节响应实验和正弦跟踪实验。所设计的非线性弹性机构结构紧凑、重量轻、扭矩质量比大。
{"title":"A novel design method of a nonlinear elastic mechanism for series elastic actuators","authors":"Wenjie Ju , Jingfu Zhao , Wenjie Zhang , Shiyu Li , Rongjie Kang , Jian S. Dai , Zhibin Song","doi":"10.1016/j.mechmachtheory.2024.105775","DOIUrl":"10.1016/j.mechmachtheory.2024.105775","url":null,"abstract":"<div><p>Series elastic actuators with increasing nonlinear stiffness(NlSEA) have promising applications in human-machine interactions for the existence of a nonlinear elastic mechanism that supplies inherent safety and can implement high torque resolution under low load and quick dynamic response under high load. In this study, a novel design method for a nonlinear elastic mechanism that can be applied in NlSEA is proposed. By combining the S-shaped cantilever beam and specialized cam surface, this study proposed an analytical approach to design a nonlinear elastic mechanism satisfying a given stiffening torque-deformation relationship. The geometric parameters constraints were discussed to support parameter determination. Two kinds of cases of nonlinear elastic mechanisms with increasing and constant stiffness characteristics were conducted to verify the effectiveness and generalizability of the proposed design method by simulations. Moreover, a nonlinear elastic mechanism with an increasing stiffness characteristic was designed and a prototype was fabricated. A torque-deformation verification experiment, regulation response experiments, and sinusoidal tracking experiments were conducted to verify the accuracy, response performance, and tracking performance of the prototype. The designed nonlinear elastic mechanism has a large torque-to-mass ratio in a compact and lightweight structure.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"202 ","pages":"Article 105775"},"PeriodicalIF":4.5,"publicationDate":"2024-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142117584","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 : 2024-08-30DOI: 10.1016/j.mechmachtheory.2024.105774
Na Li , Fei Li , Hao Yang , Haijun Peng
Soft robots are high-dimensional nonlinear systems coupled with both geometric and material nonlinearity. Control of such a system is complex and time-consuming. In this study, a real-time trajectory tracking control framework is established based on the reduced order extended position-based dynamics. In contrast to the common nonlinear model order reduction methods that require to collect a large number of data to create the motion subspace, this article's motion subspace is constructed based on the model configuration and material properties. The linear modes of the model and the related modal derivatives provide the reduced order matrix, which streamlines and increases the efficiency of model construction. Then, coupled with the instantaneous optimal control, a real-time reduced order model-based control framework of soft robots can be constructed. Experiments on trajectory tracking of a soft manipulator are conducted to verify the accuracy and efficiency of the proposed controller. The average error of all experiments is within 1 cm; and the single-step calculation time of the controller is about 0.057 s, which is less than the sampling period 0.1 s.
软机器人是一种高维非线性系统,同时具有几何和材料非线性。对这样的系统进行控制既复杂又耗时。在本研究中,我们建立了一个基于减阶扩展位置动力学的实时轨迹跟踪控制框架。与需要收集大量数据来创建运动子空间的普通非线性模型降阶方法不同,本文的运动子空间是基于模型配置和材料属性构建的。模型的线性模态和相关模态导数提供了降阶矩阵,简化并提高了模型构建的效率。然后,结合瞬时最优控制,就能构建基于模型的软机器人实时减阶控制框架。通过对软机械手轨迹跟踪的实验,验证了所提控制器的准确性和效率。所有实验的平均误差都在 1 cm 以内;控制器的单步计算时间约为 0.057 s,小于采样周期 0.1 s。
{"title":"Real-time control of a soft manipulator based on reduced order extended position-based dynamics","authors":"Na Li , Fei Li , Hao Yang , Haijun Peng","doi":"10.1016/j.mechmachtheory.2024.105774","DOIUrl":"10.1016/j.mechmachtheory.2024.105774","url":null,"abstract":"<div><p>Soft robots are high-dimensional nonlinear systems coupled with both geometric and material nonlinearity. Control of such a system is complex and time-consuming. In this study, a real-time trajectory tracking control framework is established based on the reduced order extended position-based dynamics. In contrast to the common nonlinear model order reduction methods that require to collect a large number of data to create the motion subspace, this article's motion subspace is constructed based on the model configuration and material properties. The linear modes of the model and the related modal derivatives provide the reduced order matrix, which streamlines and increases the efficiency of model construction. Then, coupled with the instantaneous optimal control, a real-time reduced order model-based control framework of soft robots can be constructed. Experiments on trajectory tracking of a soft manipulator are conducted to verify the accuracy and efficiency of the proposed controller. The average error of all experiments is within 1 cm; and the single-step calculation time of the controller is about 0.057 s, which is less than the sampling period 0.1 s.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"202 ","pages":"Article 105774"},"PeriodicalIF":4.5,"publicationDate":"2024-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095195","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 : 2024-08-29DOI: 10.1016/j.mechmachtheory.2024.105759
Pietro Stano , Davide Lazzarini , Silvio Santoro , Mario Mihalkov , Umberto Montanaro , Alessandro Vigliani , Antonella Ferrara , Miguel Dhaens , Aldo Sorniotti
Road irregularities affect vehicle comfort by causing vertical and longitudinal acceleration oscillations. While the current ride comfort enhancement solutions are based on the compensation of the vertical acceleration of the sprung mass, the compensation of the longitudinal dynamics excited by road irregularities has been successfully explored only for in-wheel powertrains. The scope of this study is to demonstrate that also on-board electric powertrains with torsional dynamics of the half-shafts have the potential for effective compensation, thanks to the road profile preview. This paper presents a proof-of-concept nonlinear model predictive controller (NMPC) with road preview, which is assessed with a validated simulation model of an all-wheel drive electric vehicle. Three powertrain layouts are considered, with four in-wheel, four on-board, and two on-board electric machines. The control function is evaluated along multiple manoeuvres, through comfort-related key performance indicators (KPIs) that, for the four on-board layout along a road step test at 40 km/h, highlight >80% improvements. Finally, the real-time implementability of the algorithms is demonstrated, and preliminary experiments are conducted on an electric quadricycle prototype, with more than halved oscillations of the relevant variables.
{"title":"On-board electric powertrain control for the compensation of the longitudinal acceleration oscillations caused by road irregularities","authors":"Pietro Stano , Davide Lazzarini , Silvio Santoro , Mario Mihalkov , Umberto Montanaro , Alessandro Vigliani , Antonella Ferrara , Miguel Dhaens , Aldo Sorniotti","doi":"10.1016/j.mechmachtheory.2024.105759","DOIUrl":"10.1016/j.mechmachtheory.2024.105759","url":null,"abstract":"<div><p>Road irregularities affect vehicle comfort by causing vertical and longitudinal acceleration oscillations. While the current ride comfort enhancement solutions are based on the compensation of the vertical acceleration of the sprung mass, the compensation of the longitudinal dynamics excited by road irregularities has been successfully explored only for in-wheel powertrains. The scope of this study is to demonstrate that also on-board electric powertrains with torsional dynamics of the half-shafts have the potential for effective compensation, thanks to the road profile preview. This paper presents a proof-of-concept nonlinear model predictive controller (NMPC) with road preview, which is assessed with a validated simulation model of an all-wheel drive electric vehicle. Three powertrain layouts are considered, with four in-wheel, four on-board, and two on-board electric machines. The control function is evaluated along multiple manoeuvres, through comfort-related key performance indicators (KPIs) that, for the four on-board layout along a road step test at 40 km/h, highlight >80% improvements. Finally, the real-time implementability of the algorithms is demonstrated, and preliminary experiments are conducted on an electric quadricycle prototype, with more than halved oscillations of the relevant variables.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"202 ","pages":"Article 105759"},"PeriodicalIF":4.5,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S0094114X24001861/pdfft?md5=bad61528704aed0cb166c0e0228b3d1f&pid=1-s2.0-S0094114X24001861-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142095096","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}
In this paper, the impact of parameter variations on the deployable motion characteristics, mobility, input singularity, and deploying/folding performance of plane-symmetric Bricard mechanisms is studied. Firstly, two classes of revolute pair axes used to construct deployable polygon mechanisms (DGMs) are reviewed, and their value ranges are further refined. Secondly, all possible axes arrangement schemes for plane-symmetric 6R DGMs are presented for the first time. Then, an improved schematic synthesis method is proposed, which can be used to design all plane-symmetric 6R DGMs that belong to the plane-symmetric Bricard mechanisms. Thirdly, the improved design method is applied to create a series of single-degree-of-freedom plane-symmetric 6R DGMs. Then, feasible domain searches are performed, and some of them are prototyped. Subsequently, the input singularity of plane-symmetric 6R DGMs is analyzed. Finally, two deploying/folding performance indices are proposed to evaluate the performance of plane-symmetric 6R DGMs with different fully deployed and fully folded states based on actual application scenarios. This work expands the variety and quantity of DGMs, which will also advance the development of robotics, mechanical metamaterials, and kirigami mechanisms.
{"title":"Expanding the family of plane-symmetric 6R deployable polygon mechanisms by systematically exploring the layout of R-joint axes","authors":"Hao Chen , Weizhong Guo , Zhenghao Weng , Mingxuan Wang , Caizhi Zhou","doi":"10.1016/j.mechmachtheory.2024.105768","DOIUrl":"10.1016/j.mechmachtheory.2024.105768","url":null,"abstract":"<div><p>In this paper, the impact of parameter variations on the deployable motion characteristics, mobility, input singularity, and deploying/folding performance of plane-symmetric Bricard mechanisms is studied. Firstly, two classes of revolute pair axes used to construct deployable polygon mechanisms (DGMs) are reviewed, and their value ranges are further refined. Secondly, all possible axes arrangement schemes for plane-symmetric 6R DGMs are presented for the first time. Then, an improved schematic synthesis method is proposed, which can be used to design all plane-symmetric 6R DGMs that belong to the plane-symmetric Bricard mechanisms. Thirdly, the improved design method is applied to create a series of single-degree-of-freedom plane-symmetric 6R DGMs. Then, feasible domain searches are performed, and some of them are prototyped. Subsequently, the input singularity of plane-symmetric 6R DGMs is analyzed. Finally, two deploying/folding performance indices are proposed to evaluate the performance of plane-symmetric 6R DGMs with different fully deployed and fully folded states based on actual application scenarios. This work expands the variety and quantity of DGMs, which will also advance the development of robotics, mechanical metamaterials, and kirigami mechanisms.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"202 ","pages":"Article 105768"},"PeriodicalIF":4.5,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142088351","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 : 2024-08-27DOI: 10.1016/j.mechmachtheory.2024.105778
Rui Chen , Luna Zhou , Ke Wu , Lifu Liu , Yifan Liu , Xin Li , Guimin Chen , Gang Zheng , Jun Luo
Compliant deployable mechanisms (CDMs), as a novel and promising type of mechanisms, have been gradually used in medical industry, aerospace and other engineering fields that require high space utilization and compactness. Therefore, it is necessary to develop a general and efficient methodology to design and analyze CDMs. This paper proposes a general framework for designing and analyzing CDMs. The proposed framework has been verified by finite element method (FEM) first. Then, for practical validation, we design two types of compliant deployable mechanisms for different application scenarios within this framework, and experimental testing has been conducted to prove the feasibility of the proposed framework. Compared to the existing methods for designing CDMs, this framework demonstrates a more general scheme where different engineering scenarios can be taken into account to meet the design requirements, presenting several desired advantages over the existing methods, such as higher accuracy and less computational expense.
{"title":"A general framework for designing compliant deployable mechanisms via geometrically exact beam theory","authors":"Rui Chen , Luna Zhou , Ke Wu , Lifu Liu , Yifan Liu , Xin Li , Guimin Chen , Gang Zheng , Jun Luo","doi":"10.1016/j.mechmachtheory.2024.105778","DOIUrl":"10.1016/j.mechmachtheory.2024.105778","url":null,"abstract":"<div><p>Compliant deployable mechanisms (CDMs), as a novel and promising type of mechanisms, have been gradually used in medical industry, aerospace and other engineering fields that require high space utilization and compactness. Therefore, it is necessary to develop a general and efficient methodology to design and analyze CDMs. This paper proposes a general framework for designing and analyzing CDMs. The proposed framework has been verified by finite element method (FEM) first. Then, for practical validation, we design two types of compliant deployable mechanisms for different application scenarios within this framework, and experimental testing has been conducted to prove the feasibility of the proposed framework. Compared to the existing methods for designing CDMs, this framework demonstrates a more general scheme where different engineering scenarios can be taken into account to meet the design requirements, presenting several desired advantages over the existing methods, such as higher accuracy and less computational expense.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"202 ","pages":"Article 105778"},"PeriodicalIF":4.5,"publicationDate":"2024-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142084440","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 : 2024-08-26DOI: 10.1016/j.mechmachtheory.2024.105776
Yaodong Lu, Vigen Arakelian
The objective of this paper is to propose a novel approximate solution for determining the reactions of joints in mechanical systems, which involves the influence of Coulomb friction. It is widely acknowledged that if Coulomb friction is used in determining an exact solution to the equilibrium equations for a mechanism, then it will involve nonlinear systems of equations. With the abundance of computer tools now available, tasks of this kind, especially numerical computations, are not particularly challenging. However, new analytically tractable approximate methods are still valuable as a straightforward way of solving the problem. Several studies have been carried out in this field to find a simple solution. In this paper, a new approach based on friction circle concept and Babylonian algorithm is developed for various mechanisms, which is exceptionally well-suited for calculating and streamlining the solution process for mechanical systems by eliminating the necessity for iterative steps at each stage of the force analysis.
{"title":"A new solution to force analysis including Coulomb friction in mechanism joints","authors":"Yaodong Lu, Vigen Arakelian","doi":"10.1016/j.mechmachtheory.2024.105776","DOIUrl":"10.1016/j.mechmachtheory.2024.105776","url":null,"abstract":"<div><p>The objective of this paper is to propose a novel approximate solution for determining the reactions of joints in mechanical systems, which involves the influence of Coulomb friction. It is widely acknowledged that if Coulomb friction is used in determining an exact solution to the equilibrium equations for a mechanism, then it will involve nonlinear systems of equations. With the abundance of computer tools now available, tasks of this kind, especially numerical computations, are not particularly challenging. However, new analytically tractable approximate methods are still valuable as a straightforward way of solving the problem. Several studies have been carried out in this field to find a simple solution. In this paper, a new approach based on friction circle concept and Babylonian algorithm is developed for various mechanisms, which is exceptionally well-suited for calculating and streamlining the solution process for mechanical systems by eliminating the necessity for iterative steps at each stage of the force analysis.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"202 ","pages":"Article 105776"},"PeriodicalIF":4.5,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142077346","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 : 2024-08-24DOI: 10.1016/j.mechmachtheory.2024.105777
Qilong Du, Jizhuang Fan, Tian Xu, Xiulong Cui, Jinnong Liao, Weibin Xu, Yanhe Zhu, Jie Zhao
Small jumping robots widely adopt complex catapult mechanisms. This paper presents a novel jumping strategy using dead point instead of traditional catapult mechanisms, achieving efficient energy storage and release without increasing mechanical complexity. Single degree-of-freedom (DOF) planar six-bar linkages are widely used in bionic mechanism design due to their simple control and strong design flexibility. However, their complex configuration and numerous parameters make it challenging to carry out multi-objective and multi-constraint designs. In this paper, a design method of single DOF six-bar linkages based on dead-point constraints is proposed to design a frog-inspired leg mechanism. By enumerating the basic configuration atlas and using a stepwise closed-loop method, initial value screening is completed to improve the efficiency of objective function optimization. The dead-point constraints are simplified with graphical geometric properties. The resulting mechanism satisfies multiple objectives and constraints, including shape, motion posture and trajectory, demonstrating the feasibility of the method. Simulations and experiments confirmed the excellent jumping performance of the 147.1-g prototype, with a jump height of 8.55 times leg length and an energy-storing capacity of 35.39 J/kg.
{"title":"Kinematic synthesis and mechanism design of a six-bar jumping leg for elastic energy storage and release based on dead points","authors":"Qilong Du, Jizhuang Fan, Tian Xu, Xiulong Cui, Jinnong Liao, Weibin Xu, Yanhe Zhu, Jie Zhao","doi":"10.1016/j.mechmachtheory.2024.105777","DOIUrl":"10.1016/j.mechmachtheory.2024.105777","url":null,"abstract":"<div><p>Small jumping robots widely adopt complex catapult mechanisms. This paper presents a novel jumping strategy using dead point instead of traditional catapult mechanisms, achieving efficient energy storage and release without increasing mechanical complexity. Single degree-of-freedom (DOF) planar six-bar linkages are widely used in bionic mechanism design due to their simple control and strong design flexibility. However, their complex configuration and numerous parameters make it challenging to carry out multi-objective and multi-constraint designs. In this paper, a design method of single DOF six-bar linkages based on dead-point constraints is proposed to design a frog-inspired leg mechanism. By enumerating the basic configuration atlas and using a stepwise closed-loop method, initial value screening is completed to improve the efficiency of objective function optimization. The dead-point constraints are simplified with graphical geometric properties. The resulting mechanism satisfies multiple objectives and constraints, including shape, motion posture and trajectory, demonstrating the feasibility of the method. Simulations and experiments confirmed the excellent jumping performance of the 147.1-g prototype, with a jump height of 8.55 times leg length and an energy-storing capacity of 35.39 J/kg.</p></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"202 ","pages":"Article 105777"},"PeriodicalIF":4.5,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142058383","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}