Advances in Mechanical Engineering最新文献

{"title":"Design of a personalized knee rehabilitation exoskeleton with high motion compliance","authors":"Yong Zeng, Xiaobo Peng, Zhenfeng Dai, Ying Huang, Fang Chen, Yingxi Peng","doi":"10.1177/16878132241273520","DOIUrl":"https://doi.org/10.1177/16878132241273520","url":null,"abstract":"During the motion of a knee joint, the instantaneous center of rotation (ICR) of the tibia relative to the femur is not fixed but moves along a curve decided by the joint structure. Adapting to wearer’s personalized knee joint structure is important to improve the wearing comfort and rehabilitation effect of the exoskeleton. The paper proposes a design method of a personalized knee rehabilitation exoskeleton with high human-machine compliance. Firstly, an instantaneous center curve (ICC) generation algorithm is proposed, which extracts feature points of the tibia from the medical images of the wearer’s knee joint, generates ICRs of the tibia at different knee joint angles, and then fits the ICRs into the ICC of the knee joint. Secondly, a four-bar linkage model for the knee joint is applied, and the structure parameters of the linkage are optimized by minimizing the deviations between the ICRs of the linkage and the wearer. Finally, a lower limb rehabilitation exoskeleton is implemented, adopting a lightweight transmission scheme using conjugate cams combined with Bowden cables. The experimental results show that the designed exoskeleton is lightweight and has small relative movement and small interaction forces with the wearer, realizing good wearing comfort and motion compliance.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"14 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200735","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical study on the efficiency of an electrostatic precipitator having the shape of a truncated cone","authors":"Chahine Nejma, Khaoula Ben Abdelmlek, Fayçal Ben Nejma","doi":"10.1177/16878132241272211","DOIUrl":"https://doi.org/10.1177/16878132241272211","url":null,"abstract":"This paper presents a comprehensive numerical study of a truncated conical precipitator. The main objective was to enhance the efficiency of the precipitator by exploring the influence of several parameters on particle trajectories and the evolution of the collection efficiency. The studied parameters include the cone coefficient ( D), flow velocity, applied voltage, conduit diameter and length, as well as relative permeability. For each parameter, analyses were conducted on the evolution of the collection efficiency for particles with various diameters, ranging from 0.01 to 10 μm. The results obtained from the numerical simulation on COMSOL Multiphysics<jats:sup>®</jats:sup> indicate that, regardless of the value of D, the precipitator exhibits optimal efficiency in collecting particles with extreme diameters (0.01 and 10 μm) due to the dominance of the electrical force. In contrast, particles with intermediate diameters (0.1–1 μm) present a challenge, as the drag and electric forces are too weak to ensure effective particle collection. The study highlights that a sharper tip at the top of the precipitator significantly enhances its efficiency. Increasing the applied voltage and selecting lower inner radii of the collecting electrode reinforce the electrical force and enhance particle collection. Furthermore, increasing the height of the precipitator directs particle trajectories more effectively toward the collecting electrode. The results provide valuable insights for the design of more efficient precipitators and propose practical guidelines for improving their effectiveness. These contributions are particularly important for air pollution control technologies, offering significant advancements in this field.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"15 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An efficient bivariate three-point Lagrange interpolation method based on coordinate transformation","authors":"Xianjun Sheng, Zhijie Zhao, Ning Liu, Kexin Wang","doi":"10.1177/16878132241272208","DOIUrl":"https://doi.org/10.1177/16878132241272208","url":null,"abstract":"This paper proposes a bivariate three-point interpolation method based on coordinate transformation. The transformation significantly improves computational efficiency by converting radial sampling points into interpolation nodes, while enabling high-precision computation of coordinates and normal vectors for any surface point. Numerical experiments validate the effectiveness of the bivariate three-point interpolation method based on coordinate transformation. Although its accuracy is slightly lower than that of the NURBS surface method, it still meets the requirement for high precision. In particular, the proposed method drastically reduces the computation time by more than 50% compared to the NURBS surface method. In addition, it seamlessly computes coordinates and normal vectors for any surface point. It is significantly helpful for the improvement of computational efficiency in engineering for the measurement and evaluation of aircraft radomes.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"3 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200737","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Descriptive parameter optimization method for energy-saving gait planning of biped robots","authors":"Yun Meng, Zhiqiang Lu, Peipei Wang","doi":"10.1177/16878132241260583","DOIUrl":"https://doi.org/10.1177/16878132241260583","url":null,"abstract":"Low energy efficiency is an important factor restricting the application and development of biped robots. In this article, an energy-saving walking control method using descriptive parameter optimization to obtain the gait type with minimum energy consumption is proposed. The algorithm evaluates the energy consumed during walking considering the load torque and angular velocity of all joint actuators of the five-mass simplified model of the robot. A gait database with the step length, gait type and stability margin as the input and gait parameters and energy consumption as the output is constructed, and the gait adapted to the zero-moment point region is dynamically adjusted during walking to realize a compromise between the robot walking stability and energy consumption. In the gait parameter optimization part of the algorithm, a mapping relationship between the descriptive parameters and body trajectory is established. Through parameter sampling and inverse kinematics calculations, seeds are selected from the sample set according to the stability margin, and the gradient descent method of directional acceleration is used to approximate the minimum energy consumption under the descriptive parameters in the neighborhood of the seeds. In the gait synthesis part of the algorithm, according to the given walking task and the energy consumption-related items in the gait database, the walking trajectory with minimum energy consumption is planned. In real-time walking, the database is queried according to the planned step sequence, the gait parameters are obtained, the robot joint movement is controlled, the feedback zero-moment point is calculated from the robot foot pressure, and the database input query is adjusted according to the trajectory deviation to simultaneously achieve walking stability and reduce energy consumption. To determine the effectiveness of the algorithm, dynamic simulation experiments and real robot walking experiments are carried out. The experimental results show that our algorithm has a significant energy-saving effect. The experimental videos are available at https://github.com/xkluzq/biped-robot .","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"95 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200738","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and simulation optimization of key device of water jet grassland root cutting machine","authors":"Jianguo Qin, Bo Yang, Haitang Cen, Haixia Gong, Hongyan Yang, Yunhe Zou, Sijia Guo","doi":"10.1177/16878132241265860","DOIUrl":"https://doi.org/10.1177/16878132241265860","url":null,"abstract":"In view of the current situation of gradual degradation of grassland, this paper designs a water jet grassland root cutting machine based on root cutting improvement technology. The machine achieves the purpose of restoring grassland by the impact of high-pressure fluid on soil. In order to improve the working efficiency, an adaptive position adjustment device (following is referred to as APA device) is designed, which can ensure the adaptability of the fluidic sprinkler to the ground. In this regard, the overall structure and working principle of the water jet grassland root cutting machine are first analyzed. Furthermore, the dynamic model of the APA device is established based on the Lagrange equation, and the motion process of the device is simulated by MATLAB/SimMechanics. The results show that the APA device has good working efficiency in the smooth ground, and there is a significant vibration response in the protuberant ground. In order to reduce the vibration interference, the structure of the APA device is optimized based on the simulation results. The optimized simulation results show that the vibration response generated during the operation of the APA device is reduced, the vibration interference is reduced, and the optimization effect is significant.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"76 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932641","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Numerical investigation on thermal behaviors of Heat Sinks and Hybrid Heat Sinks with different PCMs for electronic cooling","authors":"Burcu Çiçek","doi":"10.1177/16878132241269229","DOIUrl":"https://doi.org/10.1177/16878132241269229","url":null,"abstract":"In this study, a numerical method was used to investigate the melting process of PCM-Heat Sink and PCM-Hybrid Heat sinks for electronic cooling. Firstly, three different PCMs, designated as RT-28HC, RT-31, and RT-54HC, with varying thermophysical properties, were used within aluminum finned heat sink and three-dimensional time-dependent analyses was conducted using the ANSYS Fluent software, at heat fluxes of 3.6, 4.2, and 4.8 kW/m<jats:sup>2</jats:sup>. To calculate the enhancement ratio in the PCM-Heat Sink, setpoint temperatures of 45°C and 60°C were selected. The results revealed that RT-54HC is the best option among them, since it produced the lowest heat sink base temperature at the end of 120 min simulation period. At last, two hybrid heat sink models, designated as HPCM1 and HPCM2 were designed and their cooling performances were analyzed at heat transfer coefficients of 5, 10, and 15 W/m K. The RT-54HC was used as the PCM for hybrid heat sinks at a heat flux of 4.8 kW/m<jats:sup>2</jats:sup>. It was observed that HPCM1, with heat conductivity coefficients of 10 and 15 W/m<jats:sup>2</jats:sup> K were more effective than PCM-HS models for cooling. In conclusion, this study provides useful guidelines for designing heat sinks and selecting PCM types for electronic cooling.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"3 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932642","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimum analysis of inclined angle of mixing blades in planetary mixer based on discrete element method","authors":"Wenmin Lu, Shumei Chen, Jinan Zheng, Xinyuan Fu, Guohua Fu, Jia Zhong, Qingyang Li, Zhuangbin Zhen","doi":"10.1177/16878132241269238","DOIUrl":"https://doi.org/10.1177/16878132241269238","url":null,"abstract":"Based on production practice, it is known that the mixing scraper is an important mechanical part that the planetary mixer directly contacts with the concrete. Its structural shape will directly affect the mixing effect of the mixer, and the inclination angle of the mixing scraper is one of the most important factors affecting the mixing efficiency of the mixer. In this paper, based on the discrete element numerical analysis method, a three-dimensional simulation model of the vertical axis planetary concrete mixer is established, and the concrete mixing process is simulated, and the inclination angle of the mixing scraper is optimized based on the simulation results. An automatic precast concrete mixing experiment platform was built, and the simulation results were verified experimentally. The research results show that the experimental data and the simulation results are very consistent, which verifies the accuracy of the discrete element dynamics simulation model. It can be seen from the simulation and experimental results that the mixing efficiency of the mixer is the highest when the inclination angle of the mixing blade is 45°, and the number of collisions between different types of material particles in the mixing tank is the highest.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"46 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"One improved YOLOX-s algorithm for lightweight section-steel surface defect detection","authors":"Jian-Zhou Pan, Chi-Hsin Yang, Long Wu, Xiao Huang, Sijie Qiu","doi":"10.1177/16878132241266456","DOIUrl":"https://doi.org/10.1177/16878132241266456","url":null,"abstract":"This study introduces an improved lightweight section-steel surface detection (ILSSD) YOLOX-s algorithm model to enhance feature fusion performance in single-stage target detection networks, addressing the low accuracy in detecting defects on section-steel surfaces and limited computing resources at steel plants. The ILSSD YOLOX-s model is improved by introducing the deep-wise separable convolution (DSC) module to reduce parameter count, a dual parallel attention module for improved feature extraction efficiency, and a weighted feature fusion path using bi-directional feature pyramid network (BiFPN). Additionally, the CIoU loss function is employed for boundary frame regression to enhance prediction accuracy. Based on the NEU-DET dataset, experimental results demonstrate that the ILSSD YOLOX-s algorithm model achieves a 75.9% mean average precision with an IoU threshold of 0.5 (mAP@0.5), an improvement of 7.1 percentage points over the original YOLOX-s model, with a detection speed of 78.4 frames per second (FPS). Its practicality is validated through training and validating it with a lightweight section-steel surface defect dataset from an industrial steel plant, further confirming its viability for industrial defect detection applications.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"22 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of wheel brow structures of a van considering rainwater pollutants based on discrete phase model","authors":"Yu Shi, Dan Zhang, Yan Zheng, Lanchun Zhang, Tianbo Wang, Jun Yang","doi":"10.1177/16878132241269243","DOIUrl":"https://doi.org/10.1177/16878132241269243","url":null,"abstract":"Four optimization models were proposed to reduce the impact of pollutants from vans on themselves and surrounding vehicles. The adsorption of pollutants on the body of the van in rainy conditions and the diffusion of pollutants into the external environment were numerically investigated using the Discrete Phase Model (DPM) for vans having different wheel brow structures. The pressure distribution on the surface of the van, the surrounding flow field, and the raindrop distributions of various external positions on and around the van were analyzed and compared. The results indicated that the van with externally covered wheel brow model was most effective in inhibiting the diffusion of rainwater pollutants from the van under rainy conditions. Compared with the original model, the reduction in the polluted area was 11.19%, the reduction in the influence of the visual field on the rear vehicle was 25.4%, and the reduction in the diffusion of pollutants on the bodies of the side vehicle was 20.7%.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"85 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932522","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Type synthesis of 3-DOF spherical hybrid mechanisms with fixed centers of rotation","authors":"Shuyang Shi, Kai Li, Zheng Ma, Huiqiang Wang, Xuesong Qiu, Yulin Zhou","doi":"10.1177/16878132241258634","DOIUrl":"https://doi.org/10.1177/16878132241258634","url":null,"abstract":"To improve the load-bearing capacity and the rotation range about the normal of the moving platform in a spherical parallel mechanism (SPM), a type synthesis method for spherical hybrid mechanisms (SHMs) with fixed centers of rotation is proposed by coupling a serial transmission chain with the central passive limb chain of the SPM near its center area. Based on the analysis of the spherical mechanism configuration’s research status with a fixed rotation center, a method for systematically synthesizing SHMs is given, and four types of limb chains are developed. The possible limb constraint systems provided by each type of limb chain are analyzed via screw theory, and the type synthesis of each type of limb chain is carried out. Screening rules are proposed to obtain the preferred limb chains from the limb chain configuration results. By selecting and permuting preferred limb chains based on the mechanism’s center position of rotation and the constraint type, a series of SHMs that rotate unrestricted about the normal of the moving platform are produced. Selecting the RBR-2RRR SHM as an example, its workspace, singularity, dexterity, and stiffness are analyzed to verify the effectiveness of the research. This work enriches the configuration types of SHMs and provides theoretical support for the design and applications of SHMs in engineering.","PeriodicalId":7357,"journal":{"name":"Advances in Mechanical Engineering","volume":"36 1","pages":""},"PeriodicalIF":2.1,"publicationDate":"2024-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141932640","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}