Mechanism and Machine Theory最新文献

英文中文

Design and investigation of ground micro-gravity experimental system for large space spinning structures

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-24 DOI: 10.1016/j.mechmachtheory.2024.105891

Guo Wei, Jialiang Sun, Xinyuan Li, Jiaojiao Guo, Dongping Jin

On-orbit dynamic stability of a spacecraft system with a large space structure is affected by external forces and actuator-induced perturbations. To effectively predict the on-orbit dynamic behavior of large space structures, it is urgent to validate them by ground experiments. This paper designs a novel micro-gravity experimental system for simulating the on-orbit operation state of a large space structure and conducting its ground vibration testing research. Firstly, the experimental system uses a spherical air-bearing and a gear-rotating device to achieve frictionless rotational motion of the large space structure. Secondly, two eccentric rotors are employed to simulate an actuator, serving as an on-orbit perturbation source to excite the dynamic characteristics of the large space structure. At the same time, a real-time digital image correlation (DIC) deformation measurement system captures the full-field displacement. Finally, an on-orbit dynamic experiment is conducted on the large space structure in the ground micro-gravity experimental system, and the effectiveness of the experimental system is validated through numerical simulation results.

{"title":"Design and investigation of ground micro-gravity experimental system for large space spinning structures","authors":"Guo Wei, Jialiang Sun, Xinyuan Li, Jiaojiao Guo, Dongping Jin","doi":"10.1016/j.mechmachtheory.2024.105891","DOIUrl":"10.1016/j.mechmachtheory.2024.105891","url":null,"abstract":"<div><div>On-orbit dynamic stability of a spacecraft system with a large space structure is affected by external forces and actuator-induced perturbations. To effectively predict the on-orbit dynamic behavior of large space structures, it is urgent to validate them by ground experiments. This paper designs a novel micro-gravity experimental system for simulating the on-orbit operation state of a large space structure and conducting its ground vibration testing research. Firstly, the experimental system uses a spherical air-bearing and a gear-rotating device to achieve frictionless rotational motion of the large space structure. Secondly, two eccentric rotors are employed to simulate an actuator, serving as an on-orbit perturbation source to excite the dynamic characteristics of the large space structure. At the same time, a real-time digital image correlation (DIC) deformation measurement system captures the full-field displacement. Finally, an on-orbit dynamic experiment is conducted on the large space structure in the ground micro-gravity experimental system, and the effectiveness of the experimental system is validated through numerical simulation results.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105891"},"PeriodicalIF":4.5,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166303","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}

引用次数: 0

Modeling, optimization, and control of a variable stiffness pneumatic rotary joint with soft-rigid hybrid twisting modules

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-24 DOI: 10.1016/j.mechmachtheory.2024.105899

Zhujin Jiang , Ketao Zhang

Soft actuators have seen significant advancements in recent years, driven by their potential for adaptive and safe actuation in various applications. However, soft pneumatic actuators may exhibit undesirable deformation, bringing challenges in kinematic modeling and motion control. To address these issues, this paper systematically investigates a soft-rigid hybrid pneumatic rotary joint that integrates two antagonistic twisting modules in series—one performs clockwise helical motion, and another produces anticlockwise helical motion. Theoretical models for the rotary joint's angular displacement, output torque, and stiffness are revealed and verified through simulation and experiments. Experimental results show that the rotary joint can adjust its angular displacement, output torque and stiffness by changing the pressures of two bellows muscles. Additionally, with a classical PID controller, the rotary joint can follow triangle waves with a frequency of 0.5 Hz with a mean absolute error of 3.35° and resist an external disturbance of 1 Nm. The variable stiffness pneumatic rotary joint contains no electronic components, thereby having the potential for applications in electronics-free robots operating in extreme environments, such as nuclear power stations, and explosive gas platforms.

{"title":"Modeling, optimization, and control of a variable stiffness pneumatic rotary joint with soft-rigid hybrid twisting modules","authors":"Zhujin Jiang , Ketao Zhang","doi":"10.1016/j.mechmachtheory.2024.105899","DOIUrl":"10.1016/j.mechmachtheory.2024.105899","url":null,"abstract":"<div><div>Soft actuators have seen significant advancements in recent years, driven by their potential for adaptive and safe actuation in various applications. However, soft pneumatic actuators may exhibit undesirable deformation, bringing challenges in kinematic modeling and motion control. To address these issues, this paper systematically investigates a soft-rigid hybrid pneumatic rotary joint that integrates two antagonistic twisting modules in series—one performs clockwise helical motion, and another produces anticlockwise helical motion. Theoretical models for the rotary joint's angular displacement, output torque, and stiffness are revealed and verified through simulation and experiments. Experimental results show that the rotary joint can adjust its angular displacement, output torque and stiffness by changing the pressures of two bellows muscles. Additionally, with a classical PID controller, the rotary joint can follow triangle waves with a frequency of 0.5 <em>Hz</em> with a mean absolute error of 3.35° and resist an external disturbance of 1 <em>Nm</em>. The variable stiffness pneumatic rotary joint contains no electronic components, thereby having the potential for applications in electronics-free robots operating in extreme environments, such as nuclear power stations, and explosive gas platforms.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105899"},"PeriodicalIF":4.5,"publicationDate":"2024-12-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165143","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}

引用次数: 0

Dynamic characteristics analysis and multi-source disturbances rejection control of a 6-PUS parallel stabilization mechanism on floating base

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-20 DOI: 10.1016/j.mechmachtheory.2024.105888

Chaoxiong Lin , Baogeng Xin , Shuojie Wang , Songlin Zhou , Weixing Chen , Feng Gao

The safety and efficiency of marine transfers are significantly influenced by the vessel motion under random wave excitations. The conventional ship-mounted stabilization platforms based on the Stewart-Gough platform design face limitations such as inadequate vertical workspace and additional inertial forces. To overcome these challenges, this study introduces a novel parallel stabilization mechanism, with kinematic and dynamic models that incorporate the motion of the floating base and the inertia characteristics of the limbs. To tackle the control difficulties posed by various marine disturbances, an innovative composite control scheme is proposed. This scheme employs a non-singular terminal sliding mode control, designed using a double power reaching law, to enhance tracking speed and vibration suppression. Additionally, a disturbance estimator is developed to mitigate external disturbances by generating a compensatory signal on the input channel that counteracts the effects of these disturbances. Theoretical analysis confirms the stability of the proposed approach, while simulation results further demonstrate its effectiveness and superior performance.

{"title":"Dynamic characteristics analysis and multi-source disturbances rejection control of a 6-PUS parallel stabilization mechanism on floating base","authors":"Chaoxiong Lin , Baogeng Xin , Shuojie Wang , Songlin Zhou , Weixing Chen , Feng Gao","doi":"10.1016/j.mechmachtheory.2024.105888","DOIUrl":"10.1016/j.mechmachtheory.2024.105888","url":null,"abstract":"<div><div>The safety and efficiency of marine transfers are significantly influenced by the vessel motion under random wave excitations. The conventional ship-mounted stabilization platforms based on the Stewart-Gough platform design face limitations such as inadequate vertical workspace and additional inertial forces. To overcome these challenges, this study introduces a novel parallel stabilization mechanism, with kinematic and dynamic models that incorporate the motion of the floating base and the inertia characteristics of the limbs. To tackle the control difficulties posed by various marine disturbances, an innovative composite control scheme is proposed. This scheme employs a non-singular terminal sliding mode control, designed using a double power reaching law, to enhance tracking speed and vibration suppression. Additionally, a disturbance estimator is developed to mitigate external disturbances by generating a compensatory signal on the input channel that counteracts the effects of these disturbances. Theoretical analysis confirms the stability of the proposed approach, while simulation results further demonstrate its effectiveness and superior performance.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105888"},"PeriodicalIF":4.5,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166302","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}

引用次数: 0

Generalized optimization approach to design in-plane distributed compliant remote center of motion mechanism

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-20 DOI: 10.1016/j.mechmachtheory.2024.105890

Zhaowei Zhang , Michael Pieber , Johannes Gerstmayr

Remote center of motion (RCM) mechanisms are widely used because their center of rotation is outside the mechanical device. Usually, compliant RCM mechanisms use a linkage-based design with flexure hinges to achieve relative motion. It is still an open question to design a distributed compliant RCM mechanism using flexural beams. Addressing this, the paper proposes a generalized optimization approach for the design. The optimization approach is implemented in two steps. First, we use beams to establish a dual-layer ground structure. Using a genetic algorithm and considering the relative density of beams as variables, we obtain the optimized topology. Second, based on the topology and employing curved beams for size-shape optimization, we achieve optimized distributed compliant RCM mechanisms. Based on this approach, we explore and identify four distinct topologies and four detailed distributed compliant RCM mechanisms. With the comparison of stiffnesses and rotational axis shift, two kinds of optimized distributed compliant RCM mechanisms are considered. For verification, the commercial finite element software ABAQUS and experimental testing were utilized, demonstrating excellent alignment. Ultimately, this approach can be generalized for optimizing distributed compliant RCM mechanisms.

{"title":"Generalized optimization approach to design in-plane distributed compliant remote center of motion mechanism","authors":"Zhaowei Zhang , Michael Pieber , Johannes Gerstmayr","doi":"10.1016/j.mechmachtheory.2024.105890","DOIUrl":"10.1016/j.mechmachtheory.2024.105890","url":null,"abstract":"<div><div>Remote center of motion (RCM) mechanisms are widely used because their center of rotation is outside the mechanical device. Usually, compliant RCM mechanisms use a linkage-based design with flexure hinges to achieve relative motion. It is still an open question to design a distributed compliant RCM mechanism using flexural beams. Addressing this, the paper proposes a generalized optimization approach for the design. The optimization approach is implemented in two steps. First, we use beams to establish a dual-layer ground structure. Using a genetic algorithm and considering the relative density of beams as variables, we obtain the optimized topology. Second, based on the topology and employing curved beams for size-shape optimization, we achieve optimized distributed compliant RCM mechanisms. Based on this approach, we explore and identify four distinct topologies and four detailed distributed compliant RCM mechanisms. With the comparison of stiffnesses and rotational axis shift, two kinds of optimized distributed compliant RCM mechanisms are considered. For verification, the commercial finite element software ABAQUS and experimental testing were utilized, demonstrating excellent alignment. Ultimately, this approach can be generalized for optimizing distributed compliant RCM mechanisms.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105890"},"PeriodicalIF":4.5,"publicationDate":"2024-12-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166264","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}

引用次数: 0

Singularities of ABB’s YuMi 7-DOF robot arm

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-17 DOI: 10.1016/j.mechmachtheory.2024.105884

Milad Asgari , Ilian A. Bonev , Clément Gosselin

ABB’s YuMi is a unique, innovative cobot but it is also one of the most challenging 7-degree-of-freedom (DOF) robot arms on the market, in terms of kinematics. Indeed, unlike some other 7-DOF robot arms with revolute joints, in YuMi, consecutive joint axes are normal to each other, but not intersecting. And despite being invented over a decade ago, there is surprisingly little information available about its kinematics. To effectively incorporate this manipulator into motion planning tasks, it is essential to have a comprehensive grasp of its arm angle and singularities. In this paper, we use the screw dependency approach with a novel combinatorial technique and Grassmann geometry of lines to identify and categorize, for the first time, the kinematic singularities of YuMi based on simple geometrical conditions. This methodology allows for a systematic and clear understanding of the robot’s singular configurations. In addition, we provide the definition of the arm angle used by ABB and a formula for the angle calculation. Then, we describe the representation singularity, and explain the algorithmic singularities that are related to the arm angle.

{"title":"Singularities of ABB’s YuMi 7-DOF robot arm","authors":"Milad Asgari , Ilian A. Bonev , Clément Gosselin","doi":"10.1016/j.mechmachtheory.2024.105884","DOIUrl":"10.1016/j.mechmachtheory.2024.105884","url":null,"abstract":"<div><div>ABB’s YuMi is a unique, innovative cobot but it is also one of the most challenging 7-degree-of-freedom (DOF) robot arms on the market, in terms of kinematics. Indeed, unlike some other 7-DOF robot arms with revolute joints, in YuMi, consecutive joint axes are normal to each other, but not intersecting. And despite being invented over a decade ago, there is surprisingly little information available about its kinematics. To effectively incorporate this manipulator into motion planning tasks, it is essential to have a comprehensive grasp of its arm angle and singularities. In this paper, we use the screw dependency approach with a novel combinatorial technique and Grassmann geometry of lines to identify and categorize, for the first time, the kinematic singularities of YuMi based on simple geometrical conditions. This methodology allows for a systematic and clear understanding of the robot’s singular configurations. In addition, we provide the definition of the arm angle used by ABB and a formula for the angle calculation. Then, we describe the representation singularity, and explain the algorithmic singularities that are related to the arm angle.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105884"},"PeriodicalIF":4.5,"publicationDate":"2024-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166263","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}

引用次数: 0

Horizon-stability control for wheel-legged robot driving over unknow, rough terrain

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-14 DOI: 10.1016/j.mechmachtheory.2024.105887

Kang Xu , Shoukun Wang , Lei Shi , Jianyong Li , Binkai Yue

Maintaining the horizontal and stable posture of a robot while traversing unfamiliar, rugged terrain poses a significant challenge in various applications such as wounded rescue and disability assistance. This paper introduces a horizontal-stability control framework designed for a wheel-legged hybrid robot to ensure the stability and horizontal orientation of the robot's trunk when encountering unknown and rough terrain conditions. This framework primarily comprises a compliance controller and a terrain adaptation controller. The compliance controller is geared towards establishing compliant interactions with the terrain and tracking the desired ground reaction forces. This is achieved through the implementation of a novel adaptive impedance control method to uphold torque equilibrium in the robot's trunk. To conform to the variable terrain, the terrain adaptation controller is employed. This controller decouples posture adjustments and regulates control outputs to adapt to terrains featuring unknown topographical changes. A series of numerical simulations and experimental trials are carried out to validate the proposed methods on a wheel-legged hybrid robot, followed by comparative evaluations to assess its performance.

{"title":"Horizon-stability control for wheel-legged robot driving over unknow, rough terrain","authors":"Kang Xu , Shoukun Wang , Lei Shi , Jianyong Li , Binkai Yue","doi":"10.1016/j.mechmachtheory.2024.105887","DOIUrl":"10.1016/j.mechmachtheory.2024.105887","url":null,"abstract":"<div><div>Maintaining the horizontal and stable posture of a robot while traversing unfamiliar, rugged terrain poses a significant challenge in various applications such as wounded rescue and disability assistance. This paper introduces a horizontal-stability control framework designed for a wheel-legged hybrid robot to ensure the stability and horizontal orientation of the robot's trunk when encountering unknown and rough terrain conditions. This framework primarily comprises a compliance controller and a terrain adaptation controller. The compliance controller is geared towards establishing compliant interactions with the terrain and tracking the desired ground reaction forces. This is achieved through the implementation of a novel adaptive impedance control method to uphold torque equilibrium in the robot's trunk. To conform to the variable terrain, the terrain adaptation controller is employed. This controller decouples posture adjustments and regulates control outputs to adapt to terrains featuring unknown topographical changes. A series of numerical simulations and experimental trials are carried out to validate the proposed methods on a wheel-legged hybrid robot, followed by comparative evaluations to assess its performance.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105887"},"PeriodicalIF":4.5,"publicationDate":"2024-12-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166262","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}

引用次数: 0

Applications of dynamics metamodels of an eccentric crank-slider mechanism in the initial phase of their design

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-13 DOI: 10.1016/j.mechmachtheory.2024.105886

Andrzej Urbaś, Jacek Stadnicki

The concept of dynamics metamodels to predict the behavior of an eccentric crank-slider mechanism is presented. The mathematical model of the system is elaborated using the formalism of joint coordinates, homogeneous transformations matrices, and Lagrange equations of the second kind. The flexibility of the drive and links, friction in joints, and external impact on the slider, for example, in the form of a bumper, are considered in the proposed model. The appropriate indicators are introduced to assess the mentioned phenomena based on the values of the kinetic energy of the slider and driving torque.

引用次数: 0

NURBS curve interpolation strategy for smooth motion of industrial robots

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-13 DOI: 10.1016/j.mechmachtheory.2024.105885

Yonghao Guo, Wentie Niu, Hongda Liu, Zengao Zhang, Hao Zheng

Smooth motion is crucial for industrial robots to efficiently execute accurate path tracking tasks. This paper proposes a NURBS curve interpolation strategy for smooth motion of industrial robots to reduce roughness and contour error. The strategy ensures smooth motion through two stages: feedrate planning and interpolation point parameter calculation. During the feedrate planning stage, kinematics and dynamics constraints, including torque and torque change rate, are considered in the parameter domain. Round-off error is considered, and an S-curve feedrate planning approach is employed to ensure the planned feedrate is smooth after transitioning from the parameter domain to the time domain. In the interpolation point parameter calculation stage, the displacement guidance curve is generated and updated based on the current situation. Interpolation point iteration compensation is conducted to ensure the interpolation output feedrate is smooth. Simulations and experiments are conducted to validate the effectiveness of the proposed strategy. The simulation results indicate that the proposed strategy effectively smooths the interpolation output feedrate while maintaining efficiency. The experimental results show that the strategy effectively reduces roughness and contour error.

{"title":"NURBS curve interpolation strategy for smooth motion of industrial robots","authors":"Yonghao Guo, Wentie Niu, Hongda Liu, Zengao Zhang, Hao Zheng","doi":"10.1016/j.mechmachtheory.2024.105885","DOIUrl":"10.1016/j.mechmachtheory.2024.105885","url":null,"abstract":"<div><div>Smooth motion is crucial for industrial robots to efficiently execute accurate path tracking tasks. This paper proposes a NURBS curve interpolation strategy for smooth motion of industrial robots to reduce roughness and contour error. The strategy ensures smooth motion through two stages: feedrate planning and interpolation point parameter calculation. During the feedrate planning stage, kinematics and dynamics constraints, including torque and torque change rate, are considered in the parameter domain. Round-off error is considered, and an S-curve feedrate planning approach is employed to ensure the planned feedrate is smooth after transitioning from the parameter domain to the time domain. In the interpolation point parameter calculation stage, the displacement guidance curve is generated and updated based on the current situation. Interpolation point iteration compensation is conducted to ensure the interpolation output feedrate is smooth. Simulations and experiments are conducted to validate the effectiveness of the proposed strategy. The simulation results indicate that the proposed strategy effectively smooths the interpolation output feedrate while maintaining efficiency. The experimental results show that the strategy effectively reduces roughness and contour error.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105885"},"PeriodicalIF":4.5,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166260","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}

引用次数: 0

Redefining ball screw kinematics: Analysing the limitations of traditional formulations for orbital and angular speed

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-13 DOI: 10.1016/j.mechmachtheory.2024.105882

Pello Alberdi, Aitor Arana, Aitor Oyanguren, Jon Larrañaga, Ibai Ulacia

The orbital and angular speeds of the balls are fundamental kinematic variables for predicting the dynamic performance of ball screws, including power losses, vibration analysis, ball passing frequency, and wear phenomena. However, the theoretical formulation employed in the literature to calculate these variables does not account for the effect of transversal velocity component introduced by the helix angle. The present work introduces a new formulation that fully incorporates this effect, demonstrating substantial differences between the two approaches, especially at high helix angles. Additionally, a novel experimental methodology is presented to measure the orbital speed by calculating the ratio between the orbital rotation of the ball and the angular displacement of the screw. The experimental results show strong agreement with the predictions of the proposed formulation, offering more accurate results than existing models in the literature. A detailed analysis of the error is conducted, comparing the proposed formulation with traditional literature models across various ball screw geometries. Finally, an analysis of the rolling and sliding state of the contact on the kinematics of the ball is conducted, by studying the impact of the slide-to-roll ratio.

{"title":"Redefining ball screw kinematics: Analysing the limitations of traditional formulations for orbital and angular speed","authors":"Pello Alberdi, Aitor Arana, Aitor Oyanguren, Jon Larrañaga, Ibai Ulacia","doi":"10.1016/j.mechmachtheory.2024.105882","DOIUrl":"10.1016/j.mechmachtheory.2024.105882","url":null,"abstract":"<div><div>The orbital and angular speeds of the balls are fundamental kinematic variables for predicting the dynamic performance of ball screws, including power losses, vibration analysis, ball passing frequency, and wear phenomena. However, the theoretical formulation employed in the literature to calculate these variables does not account for the effect of transversal velocity component introduced by the helix angle. The present work introduces a new formulation that fully incorporates this effect, demonstrating substantial differences between the two approaches, especially at high helix angles. Additionally, a novel experimental methodology is presented to measure the orbital speed by calculating the ratio between the orbital rotation of the ball and the angular displacement of the screw. The experimental results show strong agreement with the predictions of the proposed formulation, offering more accurate results than existing models in the literature. A detailed analysis of the error is conducted, comparing the proposed formulation with traditional literature models across various ball screw geometries. Finally, an analysis of the rolling and sliding state of the contact on the kinematics of the ball is conducted, by studying the impact of the slide-to-roll ratio.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105882"},"PeriodicalIF":4.5,"publicationDate":"2024-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143166315","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}

引用次数: 0

Improving the in-plane bearing stiffness in folded beam diaphragm flexures

IF 4.5 1区工程技术 Q1 ENGINEERING, MECHANICAL

Mechanism and Machine Theory

Pub Date : 2024-12-12 DOI: 10.1016/j.mechmachtheory.2024.105883

Moeen Radgolchin , Shorya Awtar , Ruiyu Bai , Guimin Chen

Diaphragm flexures are commonly used to generate precise out-of-plane motion while providing in-plane load bearing in various precision applications. The basic diaphragm flexure exhibits a parasitic rotation about the out-of-plane direction. While this rotational error motion can be eliminated by the use of folded beams in diaphragm flexures, the unsupported end of the folded beams leads to an elastokinematic drop in the in-plane stiffness with increasing out-of-plane displacement. In this paper, a novel sandwich design for folded beam diaphragm flexures is proposed that significantly improves this in-plane stiffness drop by mitigating the under-constraint of the unsupported ends of the folded beams. The superior performance of the sandwich design is demonstrated via non-linear Finite Element Analysis (FEA) and explained by several design insights derived from closed-form analysis. Six different diaphragm flexures including asymmetric simple beam, asymmetric folded beam, symmetric folded beam, and their sandwich versions, are investigated and categorized according to their out-of-plane stiffness, in-plane stiffness, and parasitic rotation performance. Several design guidelines are proposed to select the appropriate design based on the specific requirements of the diaphragm flexure's intended application.

{"title":"Improving the in-plane bearing stiffness in folded beam diaphragm flexures","authors":"Moeen Radgolchin , Shorya Awtar , Ruiyu Bai , Guimin Chen","doi":"10.1016/j.mechmachtheory.2024.105883","DOIUrl":"10.1016/j.mechmachtheory.2024.105883","url":null,"abstract":"<div><div>Diaphragm flexures are commonly used to generate precise out-of-plane motion while providing in-plane load bearing in various precision applications. The basic diaphragm flexure exhibits a parasitic rotation about the out-of-plane direction. While this rotational error motion can be eliminated by the use of folded beams in diaphragm flexures, the unsupported end of the folded beams leads to an elastokinematic drop in the in-plane stiffness with increasing out-of-plane displacement. In this paper, a novel sandwich design for folded beam diaphragm flexures is proposed that significantly improves this in-plane stiffness drop by mitigating the under-constraint of the unsupported ends of the folded beams. The superior performance of the sandwich design is demonstrated via non-linear Finite Element Analysis (FEA) and explained by several design insights derived from closed-form analysis. Six different diaphragm flexures including asymmetric simple beam, asymmetric folded beam, symmetric folded beam, and their sandwich versions, are investigated and categorized according to their out-of-plane stiffness, in-plane stiffness, and parasitic rotation performance. Several design guidelines are proposed to select the appropriate design based on the specific requirements of the diaphragm flexure's intended application.</div></div>","PeriodicalId":49845,"journal":{"name":"Mechanism and Machine Theory","volume":"205 ","pages":"Article 105883"},"PeriodicalIF":4.5,"publicationDate":"2024-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143165142","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}

引用次数: 0

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Mechanism and Machine Theory

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