Technical Papers - SAE Mobilus

SAE Technical Papers are written and peer-reviewed by experts in the automotive, aerospace, and commercial vehicle industries and provide the latest advances in technical research and applied technical engineering information.

Items (128,746)
In the United States, pedestrian deaths account for 18% of roadway fatalities and have increased 78% since their lowest point in 2009. U.S. consumers are increasingly purchasing larger vehicles that are responsible for a disproportionate number of pedestrian injuries. This study examined a dataset of pedestrians struck by passenger vehicles in Michigan from 2015 to 2024 to identify the unique characteristics of the tallest vehicles, large SUVs and pickups, which are contributing to increased injury. Vehicle height was categorized as the hood leading edge (HLE) height compared with the estimated pedestrian hip and waist heights from anthropometric measures. Maximum abbreviated injury scale and injury sources by body region were tabulated for three vehicle height categories. Typical kinematic patterns were observed for each relative height category and the corresponding injury frequency and impact locations. For vehicles with high hood heights, head and torso injuries were commonly from the front of the vehicle —the grille, headlights, and HLE. In contrast, head injuries sustained when pedestrians were struck by medium-height and short vehicles were primarily from the vehicle hood and windshields. Even among the tallest vehicles where the bumper was much higher than the pedestrian’s knee, leg injuries from the vehicle bumper and valance were frequent, suggesting that evaluating these vehicle components is also necessary to address lower extremity injuries. This study identified the unique pedestrian impact locations associated with the tallest vehicles, which can help guide vehicle designers when considering impact attenuation strategies to reduce injury in crashes with pedestrians.
Mueller, BeckyJermakian, Jessica
Non-traditional vehicle seating postures challenge traditional occupant protection paradigms that promote pelvis lap belt engagement. Seat-integrated restraints may promote pelvis lap belt engagement in alternative seating postures but have not been evaluated with post-mortem human subjects (PMHS) in vehicle seats. The goal of this research was to perform three 38.8 g, 56 km/h frontal impact sled tests with small-sized female PMHS in a crash environment with a vehicle seat designed for alternative seating positions. PMHS pelvis kinematics, lap belt engagement, and submarining response were compared to that of the Hybrid III 5th female (HIII-5F) in the same environment. The seat was in the rearmost seat track position, reclined 40° from vertical, and incorporated a leg rest, which elevated the feet off the floor. A seat cushion airbag (SCAB), large passenger airbag (PAB), shoulder belt pretensioner (SB P/T), and seat-integrated belt (BIS) were incorporated into the testing environment. The SCAB restricted initial downward translation of the pelvis and induced 7.7°–11.8°of initial pelvis rearward rotation. Lap belt loading of the abdominal soft tissue occurred in each test via three distinct interactions: (1) initial pelvis lap belt engagement followed by pelvis fracture and subsequent submarining; (2) lack of initial pelvis engagement and direct abdominal loading; (3) initial pelvis lap belt engagement followed by submarining. In a matched test environment, the HIII-5F did not submarine nor reproduce the entire lap belt pelvis interactions observed by the PMHS. Future research must develop better tools for predicting lap belt engagement in alternative seating positions.
Newman, RachelShin, JeesooSochor, SaraMorgan, Neal R.Gepner, Bronislaw D.Kerrigan, Jason R.Kim, YongtaeKim, Sung Rae
Applicability of the CDTire tire model in vehicle handling and stability simulations is studied in this paper by comparison with the PAC2002 tire model. Based on the physical tire 245/50 R20, corresponding CDTire and PAC2002 models are established and assembled on the multibody dynamics model of an SUV. After simulating 5 handling and stability conditions, it is found that the CDTire calculation is more time-consuming compared with PAC2002, but the increased time cost does not exceed 10%. In addition, the relative errors of the 17 evaluation indices obtained based on CDTire compared to PAC2002 do not exceed 5%. Therefore, in terms of both computational accuracy and efficiency, CDTire is suitable for application in vehicle handling and stability simulation.
Gao, FenglingWu, WenwenFei, Yuanjun
In this research, the design of a digital twin system for a Robot-Assembled Workpiece Transfer Station (RAWTS) and virtual commissioning with it were detailed, aiming for debugging high-repeatability, high-precision robotic motions. The system employs a structured three-layer digital twin framework, Physical, Digital, and Information Fusion layers, interconnected via an OPC UA communication architecture to enable real-time virtual-physical data synchronization. The 6-axis industrial robot’s kinematic model is established using the D-H parameter method, and the translational end-effector’s kinematic relationships are configured with defined OPEN/CLOSE poses. A behavior-driven digital twin model is constructed within NX MCD, incorporating lightweight-processed 3D geometry from SolidWorks. Virtual commissioning involves PLC and robot program integration, OPC UA-based signal mapping, and kinematic path planning with reachability validation to avoid singularities and collisions. Key joint angles at critical path points are optimized, and virtual-physical integration debugging is performed, resulting in first-attempt success in physical operation. The study demonstrates that the NX MCD-based digital twin approach effectively validates control logic, optimizes robot trajectories, reduces on-site debugging time, and enhances operational precision and safety, offering a practical reference for digital twin applications in robotic systems.
Zang, YupingWang, YeFu, HudaiLi, WeiweiJiang, ZhiyuWang, Dayu
Assembly sequence planning is a crucial part of process preparation in aircraft final assembly. A scientifically designed assembly sequence can significantly improve assembly efficiency and reduce costs in aircraft production. Efficient planning not only streamlines the workflow but also minimizes potential errors and rework, which are critical in high-stakes aviation manufacturing. This paper examines the constraint relationships in aircraft assembly from the perspectives of cabin constraints and system constraints, covering both spatial layout restrictions and functional logical dependencies to ensure the comprehensiveness of constraint analysis. It establishes a directed graph for the aircraft assembly outline and generates the corresponding adjacency matrix, which converts the complex constraint relationships into a structured mathematical expression for easier subsequent algorithmic processing. The Warshall algorithm and Johnson algorithm are used to check and extract contradictory constraints from the directed graph. The adjacency matrix is then employed to calculate the reachability matrix, which helps identify redundant constraints and reduces the computational effort in assembly sequence planning. Finally, the optimized constraint relationships are used to calculate the aircraft’s final assembly sequence, which generates a Gantt chart for assembly sequence planning, guiding the on-site assembly order and accelerating aircraft development efficiency. The integrated approach effectively addresses the key challenges in complex aircraft assembly sequence planning.
Guo, JingjingCun, WenyuanZhao, JiongYu, YangYang, RuiYu, Long
The shuttle vehicle is a critical piece of handling equipment in automated logistics warehouses. As its primary load-bearing component, the load plate is subject to spatial constraints, requiring both a compact structure and effective prevention of structural deformation that could compress the battery. For a shuttle vehicle load plate developed by a company—with a rated load of 1500 kg and a maximum allowable deformation of ≤ 2 mm—this study first adopts the finite element method (FEM) to analyze its structural characteristics and establish a hybrid mesh model consisting of 1D beam elements, 2D shell elements, and 3D solid elements. Symmetry constraints are applied to reduce the computational scale. The structural deformation and stress under two constraint schemes (fixed constraints and surface-to-surface contact constraints) are compared and analyzed. The results indicate that surface-to-surface contact constraints should be adopted under this working condition, and potential design risks are identified. During the analysis, mesh independence is verified to determine an appropriate mesh size, thereby avoiding errors induced by mesh dimensions. Finally, an optimization design is conducted with the goal of lightweighting. Taking the cross-sectional dimensions of the load plate’s stiffeners and the thickness of the load plate as variables, and deformation as the constraint condition, the overall structural weight is reduced from 32.7 kg to 29.6 kg through multiple gradient-based iterative optimizations, effectively achieving the lightweighting objective. Experimental results show good consistency with the computational predictions. Additionally, the manufacturing process requirements and cost impacts of the optimized scheme are analyzed, and a manufacturing solution that meets technical requirements while ensuring economic feasibility is proposed.
Liu, RuiShen, JieChen, Meng
The range energy consumption testing of electric vehicles is usually completed in an environment where the environmental chamber and chassis dynamometer are built. The vehicle is bound to the chassis dynamometer to simulate the range performance on a real road, and the vehicle's fixing method is particularly important, as it even affects the test results. In order to investigate the impact of vehicle fixation as a key testing factor on the range test results of electric vehicles, this study conducted comparative experiments using rigid fixation test vehicles at different positions. By relying on a chassis dynamometer to simulate road resistance and following the Chinese Light Vehicle Test Code (CLTC-P), a range test is conducted on the same electric vehicle under strictly controlled environmental conditions. The experiment collected data on endurance mileage, total energy consumption, and segmented energy consumption. By comparing the differences in simulated resistance and electric energy change trends of chassis dynamometer under different binding methods of test vehicles during the test process, the comprehensive energy consumption results were different. The results showed that the rigid fixation at different positions significantly affected the sliding results of the test vehicle chassis dynamometer, leading to differences in the comprehensive endurance energy consumption results. The comprehensive endurance mileage difference reached 24 kilometers, and the comprehensive energy consumption difference reached 4Wh/km. This study reveals potential sources of system bias in laboratory testing and analyzes the impact of vehicle fixation methods on comprehensive range energy consumption results. The research conclusions can provide a theoretical basis and empirical reference for improving the current standards for energy consumption and range testing of electric vehicles, and enhancing the accuracy and reproducibility of test results.
Zhou, MengJiang, ZhijieGeng, Peilin
Transient gas-liquid two-phase flow in aero-engine fuel pipelines was examined using numerical simulations, focusing on the influence of flow rate on phase change behavior. Under low-flow conditions, phase change occurred repeatedly near the pipe wall, where vapor layers formed and collapsed in an intermittent manner. These processes introduced noticeable unsteadiness in the local mass flow and pressure fields. When the flow rate was increased, vapor generation was largely confined to a narrow region adjacent to the wall, and the overall flow exhibited a more stable character. The results suggest that flow-rate-dependent phase change plays an important role in determining the stability of fuel transport and should be considered in the fire safety assessment of aircraft fuel systems.
Wu, BinXin, BoZeng, TaiSu, Zhengliang
Quayside container cranes (QCCs), essential for cargo handling in seaport operations, are particularly vulnerable to damage under strong wind conditions. This study investigates the wind-induced dynamic behavior of QCCs equipped with active anti-wind systems, focusing on the mechanisms that govern cable stress and sliding instability. A five-degree-of-freedom mathematical model is established, incorporating nonlinear cable stiffness, restricted sliding through a Kelvin-Voigt collision model, and a combined Stribeck-Coulomb friction model for the wheel-rail interface. Parametric studies are conducted to evaluate the influence of three key factors, the anti-wind cable diameter, the sliding displacement of the QCC wheel, and the wheel-rail friction coefficient, on cable stress responses. The results show that increasing the cable diameter and friction coefficient significantly reduces peak cable stress, whereas greater sliding displacement increases stress accumulation and structural vulnerability. Sensitivity analysis reveals that cable diameter has the most dominant effect on cable stress, followed by sliding displacement and friction coefficient. This work might provide theoretical foundations for the design and optimisation of wind-resistant QCC structures, as well as for the development of more reliable anti-wind protection systems in extreme conditions.
Xiang, LeiJi, HuanyuLiu, ZhiweiWang, ZiyouXu, Xinyue
Amid the rapid development of the new energy vehicle industry, the vehicle frame, as the core load-bearing component of the entire vehicle, plays a direct role in the vehicle’s safety, lightweight design, and power performance through its design and performance. Although research on new energy vehicle frames has matured, issues related to the lightweighting of drive shaft-associated structures and the balance between weight reduction and strength/stiffness still require in-depth exploration. This study focuses on the chassis of new energy vehicles, utilizing Q295 low-alloy high-strength steel. Based on the vehicle’s dimensions and mass parameters, a simplified 3D model was constructed using SolidWorks. Static analysis under bending and torsion conditions, along with a 6th-order modal analysis, was conducted using ANSYS software. Based on the analysis results, optimizations were implemented at both structural and material levels: structurally, the central crossbeam was widened, holes were opened on the crossbeam’s vertical plane to reduce weight, and the longitudinal beam welding process was optimized; materially, Q295 steel was retained in high-stress zones, while aluminum alloy replaced it in low-stress zones. The optimized frame achieved a 15% reduction in torsional stress, a 16% decrease in bending stress, a 2% reduction in torsional deformation, and a 3% decrease in bending deformation. Total mass decreased by 12.7 kg, with both strength and stiffness meeting design requirements. This approach synergistically enhances frame lightweighting and performance, providing technical support for optimizing the overall performance of new energy vehicles.
Guo, LihongWang, YiyouYang, Zihao
To safely, efficiently, and high-quality complete the mechanical testing of batch-produced manned spacecraft during the China Space Station (CSS) phase, a series of optimization measures were proposed based on system engineering principles. These measures cover the entire mechanical testing process from preparation to implementation, including: establishing a standardized mechanical testing documentation system; reducing the number of mechanical sensors that do not affect result evaluation; pre-identifying and measuring background noise; digitizing test notching and evaluation methods; and standardizing and automating testing procedures. Additionally, targeted measures for test safety and quality control were implemented, including regular inspections of reusable spacecraft components, strict control of test hazards and operational risks, and standardized management of ground support equipment (GSE) through regular inspections. The proposed optimization and control measures have been validated through applications in batch-produced manned spacecraft during the CSS phase. The results show that: the generalization rate of mechanical testing documentation exceeds 80%; the number of mechanical sensors has been reduced by more than 10%; the test preparation period has been shortened by over 4 days; test efficiency has been improved by 30%; the single-direction test duration has been reduced by more than 50%; and the total test cycle has been shortened by 25%. These results indicate that the proposed optimization and control measures are reasonable and feasible, which effectively reduces redundant test operations and items, lowers potential test risks, improves test efficiency, shortens the overall test cycle, enhances test safety, and ensures the high-quality completion of mechanical testing for batch-produced manned spacecraft.
Peng, HuakangWang, Mengchen
Aiming at the inherent instability, strong nonlinearity, and high dynamic characteristics of normal-conducting maglev suspension systems, this paper adopts a composite supervisory control scheme integrating PD control and an RBF neural network. First, a high-speed maglev train-track coupled dynamics model considering track elasticity is established. On this basis, a phased control strategy is designed: the initial phase employs a PD controller to ensure system stability, after which control is seamlessly handed over to an RBF neural network. The weights of this network are continuously refined online via a gradient descent algorithm, enabling progressive enhancement of control precision. Simulation results validate the effectiveness of this approach, confirming its superior performance in both precise suspension gap regulation and robust disturbance rejection. Consequently, the proposed method not only underpins the stable operation of maglev trains but also constitutes a reliable intelligent control framework for high-speed maglev systems.
Yu, YongZhang, JieWang, YuLiang, Shi
The construction of overhead power transmission lines in remote mountainous regions frequently relies on aerial ropeway systems, as conventional ground transportation is often impractical. However, complex terrain conditions combined with highly variable wind environments can significantly threaten the operational stability and structural safety of these cargo ropeway systems. To investigate these effects, a refined finite element model of a ropeway support was developed in ANSYS, and stochastic, time-varying wind fields were generated in MATLAB. The simulated wind time histories were applied to the numerical model to perform nonlinear transient dynamic analyses, enabling the evaluation of wind-induced displacement responses under different wind angles of attack. Based on the simulated response histories, critical stress- and displacement-sensitive regions of the support structure were identified, and the implications for structural detailing and design optimization of cargo ropeway supports were discussed.
Lv, YanfengYang, ZhonglvSun, MinggangJin, Hengdong
The vigorous rate of new spacecraft being launched has made the accurate estimation of in-orbit environmental disturbances torques paramount to reducing attitude control performance corrosion. Leveraging telemetry from an asset in low-earth-orbit, we present a novel Adaptive Super-Twisting Sliding-Mode Observer, which interlinks three techniques heretofore decoupled: 1) saturation-constrained angular-acceleration adaptation; 2) Kalman-filter preconditioning of angular velocity; and 3) state-weighted logarithmic gain with dual leakage. Denoising of raw Euler angle sequences and detection of quasi-steady epochs are achieved with a customized Kalman update, while an adaptive band-pass stage isolates the torque-related acceleration signature. Casting these filtered data into the super-twisting form, we update the log gain on-the-fly, and twin leakage terms remove excess energy with accompanying chatter rejection—without compromising bandwidth. Head-to-head telemetry tests show a positive margin headroom on noise attenuation that has to be compared with the power-gain type counterpart and that increases with the signal roughness, thereby validating the fact that this technique refines environment torque estimates and hence strengthens robustness design envelopes in next-generation attitude-control systems.
Yin, XuDeng, YuhuiChi, Dongxiang
This paper focuses on the critical issue of lubrication performance in journal bearing manufacturing, employing numerical simulation techniques to investigate how manufacturing errors from processing accuracy impact lubrication behaviors. As core components in mechanical systems—especially diesel engine crankshaft bearings operating under complex conditions—journal bearings’ lubrication performance directly determines equipment stability, energy efficiency, and service life. Manufacturing deviations-induced poor lubrication can cause increased friction, severe wear, or even failures, underscoring the research’s practical value. The study constructs a refined numerical model based on the Navier-Stokes equations within the Computational Fluid Dynamics (CFD) framework, ensuring it reliably depicts fluid flow in bearing clearances. It then systematically analyzes the lubrication responses of diesel engine crankshaft bearings under diverse operational scenarios, varying key manufacturing-related parameters: roundness degrees and clearance dimensions, which mimic real production discrepancies like tool wear or machining vibration. Additionally, the research explores shaft center trajectory variations under two extreme operating conditions, as shaft movement reflects the lubrication film’s loadbearing and stability capacities. Surface roundness and clearance are identified as pivotal to journal bearing performance: they significantly alter oil film thickness distribution—critical for avoiding metal contact—and determine the maximum fluid pressure within bearings, a key load-bearing indicator. Moreover, the amplitude and phase angle of roundness fluctuations (often overlooked) exert substantial impacts on lubrication stability and load-bearing properties, offering insights for optimizing manufacturing processes to mitigate such adverse effects: -Journal bearings. -hydrodynamic lubrication. -Form error.
Liu, JunLiu, Deliang
Inertial Friction Welding (IFW) equipment is essential for the welding process of aircraft engine shaft components. However, the absence of comprehensive fault-handling standards for domestically produced inertial friction welding equipment has hindered its further development. This study focuses on the connecting rod and motor of the 30T-IFW equipment, employing a model-based fault detection method. Through simulation, the deformation of the connecting rod and the frequency response of motor vibration acceleration under different working conditions are obtained. Additionally, a monitoring platform is proposed to collect real-time data on connecting rod deformation and motor vibration from actual welding equipment. By establishing a quantitative correlation model of connecting rod deformation-force and revealing the coupling mechanism between motor eccentricity faults and modal frequency vibrations, a hybrid diagnostic framework that combines simulation of primitive warning and measurement of calibration is proposed. At last, the simulation and experimental results verify the effectiveness of the fault diagnosis method proposed in this paper.
Yang, HaifengYuan, MingqiangSun, TaoLiang, WuGong, MaolinAn, XingyiWang, QisongLiu, Dan
Conventional aero-engine fault detection techniques tend to have problems simultaneously extracting local anomalies in sensor data and long-term temporal dependencies. To solve this problem, we propose a new fault detection scheme that only uses a Dual-Path Temporal Convolutional Network (Dual-TCN) and a Gated Recurrent Unit (GRU) module. The model, in turn, takes advantage of dual parallel branches of TCNs to extract local and global features and integrates these features with the GRU to model the progression of faults in time. Validated on the dataset of the National Aeronautics and Space Administration, called C-MAPSS, the proposed technique achieves a detection accuracy of 91.39%, which is better than CNN and LSTM baselines, demonstrating interesting improvements in the precision, recall, and F1-score. Experimental results further demonstrate the effectiveness of the dual-path feature extraction and GRU fusion strategy; this method is potentially useful to realize the real-time and accurate detection of faults in complex aero-engine systems.
Yan, ShaokaiZhang, Yongjian
The performance of modern high-speed aircraft is intrinsically linked to structural mass. As a key component that generates lift, the shape and lightweight of the wing are crucial for improving aircraft performance. This study employs the bi-directional evolutionary structural optimization (BESO) method to perform topology optimization on the wingrib structure of a modern high-speed fighter aircraft. Minimize the overall strain energy as the objective and use the wing rib volume fraction as the constraint to perform topology optimization design on the wing ribs. Based on element stress/strain energy density criteria, the method iteratively adds or removes material to efficiently construct optimal load-transfer paths within the rib configuration. Following the redesign according to the optimized topology, the structural mass was reduced by 39.236% while satisfying strength and stiffness constraints. Results demonstrate that the BESO methodology effectively generates high-efficiency load-bearing configurations for wing ribs, significantly improving material utilization efficiency and structural performance while substantially reducing wing mass. This research provides an effective approach for lightweight design and performance enhancement of critical load-bearing structures in modern high-speed aircraft.
Zhou, LeiWang, WeiGong, QuanweiZhou, JingchaoGuan, Shenxiaoge
Against the backdrop of the rapidly developing aviation manufacturing industry, there is an increasingly urgent demand for the high-volume and high-quality delivery of aircraft landing gear doors, which are critical components for ensuring flight safety. Traditional assembly methods face numerous bottlenecks, making it difficult to meet the industry’s evolving requirements. Consequently, a design study has been conducted on the assembly units for aircraft landing gear. By analyzing the structural characteristics and assembly process flow of the landing gear doors, the assembly procedures were optimized and reorganized. A pulsatile assembly unit incorporating dual-attitude modular assembly devices, an automatic transportation system, curing devices with heating, and module storage facilities was designed. Digital simulation technology was employed to perform a simulation analysis of the assembly process, verifying the feasibility of the proposed scheme. This production addressed issues such as long curing cycles for liquid gaskets, low efficiency in layered hole-making, and difficulties in transporting modular fixtures. It achieved semi-automation and intelligence in the assembly, curing, and transportation processes of landing gear doors. Compared to the production mode during the development phase, the production cycle for individual products was reduced by 50%, and annual delivery capacity increased by 100%. The research findings provide effective technical support for achieving efficient and high-quality assembly of aircraft landing gear doors.
Bo, DonghaiGao, ChunlinZhou, HouchaoChen, Yilong
To address the core requirement of “layered ripeness and non-destructive harvesting” in tobacco-growing hilly regions of China, a specialized tobacco leaf harvester was developed. Considering the challenges posed by scattered plots and complex terrain, a four-wheel steering chassis system was proposed. The platform adopts a four-wheel independent drive and steering (4WID-4WIS) configuration, powered by DC servo motors and integrated with a microcontroller-based ROS system. The resulting drive chain—comprising motors, gear reducers, and off-road tires—achieves a maximum operating speed of 0.5 m/s. A novel rotary cross-blade harvesting module was designed in conjunction with a conveyor-based transmission mechanism, enabling stratified harvesting and leaf transport. Full-condition field tests were conducted. In terms of mobility, the harvester achieved stable operation at 0.5 m/s on cement roads, 0.1–0.2 m/s in fields, and demonstrated slip-free climbing on 20° slopes. In terms of harvesting performance, the system’s adjustable modules accommodated varying plant heights; however, issues with blade grip were observed when handling irregularly slanted stalks, affecting collection efficiency. During continuous field entry and exit operations, no mechanical failures occurred, verifying the prototype’s operational stability. This study introduces an innovative combination of omnidirectional mobile chassis and stratified blade modules, offering technical support for the modernization of tobacco agriculture. Further refinement of the harvesting strategy will be pursued to enhance practicality.
Guo, TingGu, JinLi, WenTang, XiaomingLong, ChaoYang, Dongchao
With the continuous improvement of performance requirements for aviation equipment, the importance and complexity of hydraulic systems as the core carrier of flight control are becoming increasingly prominent. The cleanliness of aircraft hydraulic pipelines directly affects the reliability and flight safety of hydraulic systems, and it is necessary to use specialized cleaning and testing equipment during design and manufacturing to achieve efficient cleaning. The design of traditional cleaning equipment relies on experience-driven development, with mechanical, hydraulic, and electrical systems developed independently. There are problems such as unclear requirement definitions, low efficiency of interdisciplinary collaboration, and lagging validation, making it difficult to achieve the goal of forward design. Therefore, this study introduces Model-based Systems Engineering (MBSE) method in the development process of pipeline cleaning test equipment, proposes a modeling process based on RFLP (Requirements-Function-Logical-Physical), and uses SysML system modeling language to construct a top down design model system for aircraft hydraulic pipeline cleaning equipment. Through requirement analysis modeling, functional behavior definition, and system architecture design, the significant advantages of MBSE method in the development of complex aviation test equipment have been verified, effectively improving the bold design capability and top down design efficiency. MBSE method can not only improve the design efficiency of equipment, but also promote the intelligent and efficient operation of equipment, which has important significance for the development of intelligent manufacturing and electromechanical integration technology.
Zhang, YuxinMa, ZichenLi, QiSong, GuoqiuLi, HaiweiZhang, Jingjing
To meet the need for optimizing the dynamic performance of asymmetric gear transmissions operating under high-speed and heavy-load conditions, this study presents a refined stiffness modeling approach. A tooth-surface contact stiffness model is formulated based on Hertzian contact theory. By integrating the energy method, a coupled stiffness model is established that incorporates bending, shear, axial compression, and foundation stiffness components. Stable curves depicting the variation of mesh stiffness with the path of contact are subsequently derived by leveraging the principle of stiffness superposition. The findings demonstrate that the proposed mathematical model accurately represents the stiffness behavior of asymmetric gears as governed by the changing contact length, thereby providing a theoretical foundation for enhancing gear dynamics and extending the service life of transmission systems.
Zhao, ZeyiSun, XiaoyanWu, ZihengTang, XinLiu, YanxiaLi, Fajia
During the operation, a spring in the built-in safety valve of a dangerous goods tanker. A comprehensive failure analysis of the material was conducted through macroscopic and microscopic inspections, metallographic analysis, energy spectrum analysis (EDS), and hardness tests. The failure mode of the broken spring was brittle fracture. The fracture morphology was like that of ice sugar, and the chemical composition of the spring steel met the specified requirements. The main cause of fracture failure is the mechanical damage to the inner surface during the spring manufacturing process, which leads to stress concentration in the damaged area and ultimately results in fracture. In addition, manufacturers should strengthen and standardize the production process to prevent mechanical damage and select high-purity spring steel to improve the durability of the springs.
Yang, LijunLi, QingshanXiong, MingmingLiu, MingmingWu, JunyaoYu, LangZhang, ZeweiXie, Xumeng
To strictly balance orbital insertion precision with engineering constraints during Mars aerocapture, we present an angle-of-attack (AoA) trajectory optimization framework based on adaptive differential evolution. First, a three-degree-of-freedom flight dynamics model was established utilizing the Mars-GRAM 2024 atmospheric standard. Subsequently, we formulated a penalty function centered on apoapsis altitude deviation to enable constraint-oriented dynamic optimization. Within this framework, we introduced an adaptive, direction-guided mutation strategy that integrates global optimal individuals with elite solutions. Furthermore, a parameter update mechanism driven by mutation success rates was developed to significantly enhance algorithmic robustness and computational efficiency. The AoA command sequence for the capture phase was parameterized using a piecewise constant formulation. Comparative simulations under ±30% atmospheric uncertainty demonstrate that, within critical velocity ranges, our improved algorithm elevates the trajectory altitude by approximately 36 km compared to fixed AoA methods. Notably, it reduces convergence time by 50% while strictly adhering to spacecraft physical performance boundaries. These results underscore the method's capability to provide robust, high-precision orbital adjustment support for aerocapture missions in uncertain atmospheric environments.
Tao, Kemeng
This work introduces a novel parameter measurement model for an infrared detector. Firstly, the models for calculating the parameters of an infrared detector are studied and established, such as hysteresis, repeatability, and sensitivity. Then, experiments are implemented to validate and analyze the aforementioned parameters, demonstrating the accuracy and validity of the parameter computation model. This research has guiding significance for the accurate measurement of the index parameters of infrared detectors, and it is also helpful for the calibration method, error analysis and correction of infrared detectors.
Hu, ChangdeLi, YongQiangMiao, QiGao, SiliLiu, XiangyaoLi, Kunqi
Aiming at the problem of shaft alignment disturbed by the centroid distribution of the raft in the ship propulsion system, the quantitative influence of centroid offset on bearing load distribution and axis deformation is revealed. Based on the theory of an elastically supported continuous beam, the finite element model of the raft-shaft coupling system is established. By adjusting the position of the raft counterweight mass point (longitudinal offset range ±0.5 m) to simulate the centroid change, the static solution algorithm is used to analyze the key parameters, such as bearing load and axis alignment accuracy, under multiple groups of centroid offset conditions. It is concluded that when the centroid of the raft moves to the propeller end, the load of the 1# and 2# bearing near the propeller end increases, and the load of the 3# and 6# bearing near the thrust plate end decreases. The lateral offset of the center of mass increases, the axial offset at the stern bearing increases, the maximum deflection of the shafting increases, and the deformation of the raft structure increases. The centroid distribution of the raft is a disturbance source of the shafting alignment state, and its offset will reconstruct the bearing load distribution and cause the axis deformation. It is recommended to control the lateral offset of the center of mass at the design stage and reserve the dynamic compensation margin for the shafting alignment.
Yin, HongJin, YongWang, JunTian, Jiabing
Extreme winter weather often leads to ice accretion on transmission lines. Manual removal is inefficient, costly, and poses safety risks. To address this issue, this paper presents the design of a de-icing robot to replace manual operations for transmission line de-icing. The main content focuses on the detailed structural design of the robot, including the mobile platform, de-icing mechanism, and adaptive adjustment module. Finite element simulations are conducted on key components to verify the structural rationality and the correctness of material selection. The proposed de-icing robot enhances the safety of the de-icing process, improves operational efficiency, and provides a valuable reference for transmission line de-icing methods, demonstrating significant practical value.
Chang, HaoZhen, ChenHan, FengmeiLi, Cheng
For vibration issues induced by coupling effects between flexible barrel guide mechanisms and moving bodies in high-speed dynamic systems, this study investigated their interaction mechanism using flexible multibody dynamics principles. A solid model was developed in 3D CAD software. The modal neutral file (MNF) of the guide mechanism was generated in ABAQUS, and its contact dynamics with the moving body were simulated in ADAMS via flexible contact theory and the modal superposition method. Comparative simulations revealed that incorporating structural flexibility yielded smoother fluctuations in the moving body’s axis inclination angle, providing more accurate system behaviour characterization. Exit velocity and spin rate errors remained below 5% against theoretical values, demonstrating model reliability.
Zhu, QingCheng, ZixiangZhuo, Changfei
The brake test bench is an effective method for studying wheel-rail interaction by simulating the braking process of rail vehicles. To ensure the safe and reliable operation of the brake test bench, this article focuses on introducing a comprehensive single-wheel brake test device. A finite element model of the wheelset assembly and test bench was established, and the strength, mode, and dynamic performance of the wheelset assembly and braking system were analyzed by simulating the braking process. The analysis results indicate that the wheelset assembly and braking system meet the strength requirements of the braking test process, and the test speed is maintained below the critical speed of the test bench. This validates the rationality and safety of the brake testing device and provides a foundation for subsequent brake research.
Jing, YuhangHe, TaixiongSong, Ye
Airplane pipe assembly is an important part of the aircraft manufacturing process. There are some limitations, such as poor adaptability and a long manufacturing cycle, in conventional clamps used for clamping pipes. To avoid these limitations, this paper developed a pipe clamping system with the capability of adapting pipes with different shapes and diameters. The least squares method was used to build a coordinate system for the pipe and pipe clamp system. The kinematical model of the pipe clamp system was analyzed. A method of finding the inverse solution of mechanical kinematical parameters was proposed, and was utilized to drive a mechanism performing a positioning function. The experiment, detailed in this paper, authenticated that the positioning precision of the pipe clamp system satisfies the requirements of airplane manufacture.
Xu, JunZhao, XiWang, Wei
The hydraulic system of the mechanical lever locking device of the internal mixer and the hydraulic system of the gear rack swing hydraulic cylinder are developed. The AMESim simulation models of the two systems are established, and the simulation parameters of each hydraulic element are reasonably set. Firstly, the relationship between the opening time of the mechanical lever locking device of the internal mixer and the charging volume and pressure of the accumulator is analyzed. It is found that the locking time of the mechanical lever locking device of the internal mixer needs about 10 s, while the unlocking time is less than 0.05 s. The unlocking and rubber discharging speed is very fast, and the opening time of the mechanical lever locking device of the internal mixer will become shorter when the pressure or volume of the accumulator air bag becomes larger; Through the analysis of the hydraulic system of the rack and pinion swing hydraulic cylinder, it is obtained that when the air bag volume of the accumulator is 7.557 L, the displacement of the piston rod of the rack and pinion swing hydraulic cylinder rises fastest, which is shortened from 20 s to about 15 s; The greater the air bag pressure of the accumulator is, the faster the displacement of the piston rod of the gear rack swing hydraulic cylinder rises, which is shortened from 20 s to 18 s.
Zhang, HaoqiangCai, Liu
This paper focuses on the control challenge of the movable ladder section of an offshore boarding ladder. A dynamic sliding mode control (DSMC) method based on the backstepping approach is proposed. To address the disturbance mismatch problem in traditional control strategies, the backstepping approach is adopted for the hierarchical design of the control law, decomposing the complex nonlinear system into low-order subsystems for step-by-step processing. Meanwhile, by integrating the strong anti-disturbance advantage of DSMC, a composite control framework with disturbance compensation capability is constructed, which effectively suppresses the nonlinear disturbances caused by external disturbances and system parameter perturbations during the movement of the movable ladder section. The stability of the proposed control method is strictly proven using the Lyapunov function. Simulation results show that the speed response adjustment time of the movable ladder section is less than 10.3 ms, and the position tracking error is controlled within 1.03 mm. Compared with the traditional PID control, the rise time of DSMC is improved by 89.16%, and the tracking accuracy is improved by 90.98%. Facts fully prove that the effectiveness of the proposed method is solidly established.
Yang, LixinGuo, LidongXu, Liang
To enhance China’s disaster and accident emergency response capabilities and strengthen the digital battlefield system for emergency rescue, an integrated multi-payload unmanned aerial surveillance and communication support system has been developed for extreme weather conditions and ‘triple-disconnection’ disaster scenarios. This paper sets out to address the limitations of traditional emergency drones, including poor environmental adaptability, weak payload capacity, and operational inconvenience. The system’s resistance to wind and rain has been significantly enhanced through the optimization of its airframe design. The innovative design incorporates dual-station symmetric conjugate antennas with planar blind-spot coverage systems, integrating public and self-organizing network base stations to achieve three-dimensional signal coverage and heterogeneous network integration. This enhances ground cellular network resilience. Multi-functional reconnaissance payloads are integrated and compatible with day/night and smoke/rain scenarios, thus overcoming the limitations of single-source visual information perception. The system employs zero-length deployment and parachute recovery methods, thereby facilitating rapid deployment and terrain-independent take-off and landing capabilities. The simulation results obtained demonstrate excellent aerodynamic performance, thus permitting safe operation in wind conditions up to Force 8. The antenna system under discussion is innovative in nature and has been developed to achieve 360° three-dimensional signal coverage. The primary function of this system is to ensure sustained communication link integrity. The field trials further corroborate the aircraft’s stable low-altitude cruising capability in Force 8 winds, thereby averting congestion in constrained rescue airspace. The dual-base station design, incorporating symmetric conjugate antennas and blind-spot compensation antennas, has been demonstrated to reliably restore public ground network signals within a 6.7-kilometre radius. The development of this unmanned aerial patrol system addresses a significant gap in low-altitude rescue capabilities for intelligent unmanned equipment in harsh environments. It underpins the integrated emergency command and operations system for intelligence, command, and execution, as well as the integrated emergency communication support system spanning the air, land, and sea domains. This advancement has been demonstrated to enhance disaster response efficiency and auxiliary decision-making effectiveness under extreme conditions.
Bian, LuFang, YudongYang, JixingZhang, ChenHu, BinZhang, Mingyue
With the acceleration of population aging, the number of disabled older people is increasing, and the demand for home care is also rising. In the case of a narrow space and no gap between the bed and the ground, the transfer of patients between the wheelchair and the bed has become a challenge. Current solutions suffer from bulky designs, require caregiver assistance, and pose potential safety risks. In order to solve the above problems, this paper proposes an intelligent transfer wheelchair with voice interaction and autonomous navigation function. The wheelchair innovatively adopts a cantilever transfer device, which can enable safe and stable transfer without requiring bed-floor clearance, and has the dual functions of a wheelchair and a transfer device, effectively saving family space. The stability of the structure is verified by finite element analysis. Under the action of a 500 N load, the maximum stress and maximum displacement are within the safety limit of the material. The wheelchair is also equipped with an advanced human-computer interaction system with voice interaction and autonomous navigation functions. Users can control the operation of the wheelchair through voice. The navigation module of SLAM and the hybrid A*/Dynamic Window Approach (DWA) path planner realizes the high-precision docking of the wheelchair and the bed. The results show that the design can realize the safe transfer of disabled people between wheelchair and bed, and provide a solution for home intelligent nursing.
Wang, ShunliPeng, LiZhao, Liang
As special pressure-bearing vessels, spherical tanks are widely used in chemical, oil refining, and other fields. However, their safe operation faces the dual challenges of structural failure and leakage diffusion. Meanwhile, due to its low lower explosive limit and the low ignition energy required, propane will evaporate rapidly after leakage to form an explosive mixed gas, which may further trigger severe accidents such as combustion and explosion. Therefore, this paper takes a 3000 m3 propane spherical tank as the research object, comprehensively applies the finite element analysis method, and systematically researches stress distribution, aiming to provide theoretical support for the safety design of spherical tanks and accident prevention and control.
Huang, YuanxuanTao, GangZhang, Lijing
Fracture failure of girth welds in high-grade steel pipelines poses a critical threat to pipeline integrity. Leveraging enhanced digitalization in pipeline engineering, a statistical database has been developed to support reliability analysis based on actual operational data. This study utilizes real project data to analyze the failure probability and key influencing factors of girth welds containing crack defects, thereby providing theoretical support for safety design and risk management. To overcome the conservatism of traditional deterministic methods, a probabilistic reliability model was established, incorporating a modified PRCI-CRES ultimate tensile strain criterion. Addressing the inefficiency of standard Monte Carlo (MC) simulation in high-dimensional low-probability contexts, an efficient Hamiltonian Monte Carlo-Subset Simulation (HMC-SS) strategy was introduced. Results show that HMC-SS improves computational efficiency by 99.95% over MC, with only 0.90% relative error. Key findings include: crack depth has the strongest influence – variation from 0.92 mm to 3.68 mm, which increases failure probability by 103 times; the strength matching coefficient is dominant, and higher values reduce failure risk; strain demand exhibits a positive correlation with failure probability and couples with material properties. It is concluded that high- or equal-strength material matching should be emphasized in welding, and reliability-informed design should account for multi-parameter interactions to ensure global safety.
Yang, KaiWang, KaihongWang, BinShao, JiaYu, WeichaoZhang, Dong
In view of the problems that it is difficult to accurately control the spraying area of the mining sprinkler, and the resource waste caused by the mis-spraying material stacking area, as well as the failure of traditional radar monitoring in the complex electromagnetic environment, this paper proposes an anti-splashing system for the mining sprinkler. By combining millimeter wave radar and visual recognition fusion technology, the overall scheme of the anti-splash system is proposed. Then the control simulation of the whole system is carried out. The results show that the problem of poor control in traditional sprinkler operation can be effectively solved, and the sprinkler area can be adjusted intelligently. Finally, in order to verify the accuracy of the algorithm used in this paper, different algorithms are used for comparative experimental verification. The results show that the Modified YOLOv4 algorithm has a high accuracy of 98.75 %, which has good applicability and provides a theoretical basis for subsequent research.
Hou, Lin
Head-cover-to-stay-ring bolts in pumped-storage plants face fatigue fracture risks due to axial alternating loads, with catastrophic failure cases reported globally. In China, the absence of a unified design code in early projects produced widely divergent bolt designs. This study proposes a hybrid “field measurement and Computational Fluid Dynamics (CFD) correction” method to analyze bolt forces under turbine load-rejection transients (max. stress: 780 MPa, error <3.1%), benchmarks three Chinese standards (GB/T 22581-2024, NB/T 10135-2019, GB/T 15468-2020) for preload design, and refines their technical clauses to provide actionable guidance for future tender specifications and long-term bolt maintenance.
Long, ZheGuo, MeichaoKang, CainiLi, Chengjun
Gear-shift execution is critical to power delivery, vehicle acceleration, and driver workload in Formula Student racing vehicles. Conventional shifting solutions for sequential gearboxes are often limited by driver-dependent operation, insufficient actuator authority, incomplete torque coordination, or the absence of closed-loop gear-state confirmation. This study develops and validates a clutchless electro-pneumatic gear-shifting system for a CF700-powered Formula Student vehicle equipped with an integrated sequential dog-engagement gearbox. The system is treated as a shift-assist form of automated manual transmission, in which the driver retains gear-selection authority while shift actuation and engine torque coordination are performed electronically. Although pneumatic shifting systems are already established in motorsport applications, the present work focuses on their vehicle-specific integration through measured shift-load characterization, geometry-based actuator design, gear-position-based closed-loop control, and electronic-throttle-assisted torque intervention. Vehicle tests were conducted under straight-line acceleration, high-speed obstacle-avoidance, and endurance-oriented training conditions. Across 76 recorded shift events, no failed gear transition or missed target-gear confirmation was observed. In straight-line acceleration tests, the mean target-gear confirmation time for recorded upshifts was 96 ± 5 ms, and the representative gear-position transition interval was approximately 20 ms. The full Engine Control Unit (ECU)-controlled upshift event was 0.50 ± 0.10 s because it included the calibrated low-torque dwell and torque-recovery phase, and should therefore be interpreted as a control-event window rather than the mechanical shift duration. After powertrain-specific actuation and torque-control calibration, the developed system provides an implementation basis for similar electronically controlled sequential-gearbox racing platforms, with potential to reduce shift time and driver workload and to support improved autocross drivability and performance.
Cao, Yuanyi
As a high-precision transmission core component, the RV reducer’s performance depends on the time-varying stiffness of its core components. Building a time-varying stiffness model is essential for studying its dynamic characteristics. This paper addresses the lack of key factors in existing dynamic studies by creating a multi-factor coupled dynamic model. It analyzes the time-varying stiffness of the crankshaft bearing, involute gear, and cycloid gear-pin gear. The study also focuses on building a dynamic analysis model for the crankshaft bearing. By measuring changes in oil film thickness and initial assembly clearance caused by temperature rise, it explains how combined clearance affects bearing performance. To verify the model, a domestic RV reducer is modeled and assembled in SolidWorks. The simplified model is imported into ADAMS for simulation. Under set load and speed conditions, dynamic parameters like angular velocity and acceleration of core components are obtained. This provides a more scientific analysis method and data support for understanding the dynamic characteristics and improving the transmission performance of RV reducers.
Xuan, LiangTeng, ShaoweiHuang, RuizheWan, ZefuShao, MengqiYu, ZhishenWang, Ziyue
With the complexity of chemical warfare threats and the diversification of battlefield environments, traditional toxic agent detection methods are facing bottlenecks such as response delays, coverage blind spots, and personnel safety risks. This research focuses on the application of unmanned aerial vehicle (UAV) carried toxic agent sensor systems, aiming to analyze the methods of mounting and deploying the sensors on the UAVs, and to construct a rapid response, high-precision, and highly resistant toxic agent monitoring system. Its significance lies in two aspects: 1. Tactical value: It breaks through the time and space limitations of manual reconnaissance, realizes real-time dynamic perception and early warning of toxic agent contamination, and provides key decision-making support for battlefield command; 2. Application expansion: The research results can be transferred to counter-terrorism, nuclear, biological, and chemical emergency response fields, providing theoretical support and engineering paradigms for the development of unmanned and intelligent chemical defense equipment.
Liang, TingWen, HaoQi, YelinYan, RuiMa, TengboYang, Wen
Steel structures subjected to complex loading conditions undergo various types of damage, including fatigue, crack propagation, plastic deformation, and corrosion. As time and loads accumulate, these damages may lead to structural failure. The investigation of the damage mechanisms and constitutive models for special equipment steel structures under complex loading has been a significant challenge in engineering. This study develops a constitutive model for steel structure damage under static and dynamic loads, as well as vibration disturbances, through a normalization approach. The proposed model is validated via simulation to assess its feasibility. The findings offer a theoretical foundation for the design, life prediction, and health monitoring of steel structures in special equipment, aiming to enhance their safety and reliability. This research provides critical insights into damage analysis, failure prediction, and the optimization of repair strategies for steel structures, with significant practical implications in engineering applications.
Wang, JunYu, ZhenHuang, Yong-qiangChen, Wei-bi
In this work, molecular dynamics simulations are applied to systematically examine the influence of varying temperatures (300 K, 500 K, and 700 K) on the Elevated-temperature compression behavior and micromechanical characteristics of polycrystalline Al-Mg-Si aluminum alloy. A nanopolycrystalline model was established to analyze the stress–strain response, dislocation evolution, and crystal structure changes occurring during the deformation process. The simulation results show that the yield strength and elastic modulus both decline as temperature increases, indicating a pronounced thermal softening effect. During the early stage of plastic deformation, dislocations mainly have their nucleation sites at grain boundaries and then propagate into the grain interiors, where they form interconnected networks along with stacking faults and twin structures. This work reveals the thermal deformation mechanisms of Al-Mg-Si aluminum alloy at the atomic scale and provides theoretical guidance for the optimization of its hot-working processes.
Sun, RuifengLiu, ShoukuiWang, RuiSun, XuemeiDing, ShuliMa, Xiaofei
This study proposes an intelligent automotive roof frame design method based on the middle layer and component technology on CATIA. It aims to solve core roof modeling issues: determining geometric input quantity but uncertain attributes (tangent vectors, normal vectors, number of curve segments, number of surface patches, and boundaries), high manual interaction dependence, and poor knowledge reuse, to realize efficient design knowledge reuse. Methodologically, it builds a feature-driven parametric template, develops a knowledge rule-embedded componentized UDF library (reducing repeated modeling and geometric reconstruction needs), and integrates knowledge engineering for geometric input verification and operation direction control, eliminating curve/surface attribute uncertainty impacts. Verification shows the template stably generates roof crossbeams under simple/complex inputs, improving model robustness and reuse rate, reducing design workload, shortening verification cycles, and providing an extensible solution for white body design.
Jin, ChunningFu, XinyuHou, Wenbin
Auxiliary fuel tank systems for civil aircraft are typically employed in extended-range aircraft. As a critical structure for fuel storage, the structural safety of auxiliary fuel tanks directly impacts aircraft safety. Such tanks are generally constructed from honeycomb sandwich composite panels. Owing to their outstanding advantages, including high specific strength, light weight, and corrosion resistance, honeycomb sandwich composite panels have become the material of choice for civil aircraft fuel tanks. However, to meet the safety requirements for ventilation and leakage drainage in the sandwich structure of fuel tanks, dedicated flow channels must be created by slotting inside the honeycomb composite panels to ensure timely discharge of fuel vapor and accumulated fluid from the tank sandwich. Conventional flow channels are symmetrically arranged on the end faces of the honeycomb core, making it difficult for ventilation airflow to penetrate the center of honeycomb cells. This results in ventilation and drainage blind spots within the cells, which tend to cause accumulation of fuel vapor and residual fluid over prolonged service. Consequently, the aging of the core layer is accelerated, compromising the structural integrity of the composite panel and the service life of the fuel tank. This paper proposes an asymmetric ventilation flow channel design. By optimizing the slotting position, size, and distribution pattern of the flow channels, the limitations of the traditional symmetric layout are overcome. To accurately investigate the effect of this design on the internal ventilation performance of honeycomb composite panels, a three-dimensional flow field model of the honeycomb sandwich composite panel is established using computational fluid dynamics (CFD). The ventilation airflow distribution, velocity, and flow rate characteristics under different flow channel designs are simulated and compared with those of the conventional symmetric flow channel design. The results demonstrate that the asymmetric ventilation flow channel design improves the ventilation uniformity inside the honeycomb cells and completely eliminates the ventilation and drainage blind spots at the cell center inherent in the traditional design. Meanwhile, the design significantly enhances the ventilation gas velocity and flow rate at the center of honeycomb cells, accelerating the discharge of fuel vapor and drainage of accumulated fluid. The overall ventilation efficiency is considerably higher than that of the traditional symmetric design. This study provides a theoretical basis and technical support for the safety design of honeycomb composite panels used in auxiliary fuel tanks of civil aircraft.
Yao, LijunChen, Jun
Impact testing utilizing instrumented hammers and accelerometers is a widely adopted technique in dynamic testing. The mass loading effect of the accelerometer alters the dynamic response of the test structure, leading to deviations between the measured frequency response functions (FRFs) and their true values. Furthermore, the effects on the FRFs are contingent upon the positioning of the accelerometer, thereby causing the measured FRFs between two points to fail to meet the principle of reciprocity. This paper investigates the compensation method for the mass of a single accelerometer in impact testing. Compensation formulas for both origin–FRF and cross–FRF are derived using the frequency domain substructure decoupling method. Numerical simulations on a cantilever beam and experimental tests with milling tools validate the proposed methodology. The compensation formulas for FRFs presented in this paper are expected to enhance the measurement accuracy of FRFs in modal testing of small structures, particularly relevant for lightweight components in aerospace, aircraft, and transportation systems, where precise dynamic characterization is critical.
Tang, ZhenrongYao, Zhenqiang
In response to the challenges of training and rehabilitation for patients with leg dysfunction, this research focuses on two core requirements: “bionic adaptation” and “safety assistance”. It introduces a novel exoskeleton leg rehabilitation robot designed to support diverse rehabilitation exercises for individuals with leg disabilities during therapy. The robot system consists of a lumbar support structure, thigh mechanical components, calf mechanical components, leg fixation straps, and foot mechanical structures, and achieves multi degree of freedom motion simulation through three main joints: hip joint, knee joint, and ankle joint. Each mechanical leg has three independent degrees of freedom, which can effectively simulate the natural movements of the human lower limb, such as flexion, extension, abduction, etc., during the gait cycle, thus meeting the functional needs of patients for different movement modes during rehabilitation training. On the basis of structural design, this study further utilizes multi-body dynamics simulation software ADAMS to conduct kinematic and dynamic analysis of the exoskeleton robot. By simulating the joint torque of the exoskeleton legs under ideal working conditions, the rationality and smoothness of the mechanism design are verified. The simulation results not only reflect the performance of the robot in typical rehabilitation actions, but also provide a theoretical basis and data support for the selection and parameter matching of key execution components (such as servo motors, reducers, etc.), laying an important foundation for the physical development and control strategy optimization of the robot system.
Mu, XiaoqiMa, ChaoLi, WeijiePu, ShuaiLiu, JiaqiWang, RuiyinZhang, Xiaodong
With the strategic expansion of low-altitude economies, there is a growing demand for unmanned aerial vehicles (UAVs) with enhanced structural reliability and performance. This study investigates the integrated design and precision manufacturing of a heavy-lift quadrotor UAV, focusing on developing a system capable of sustaining substantial payloads. The UAV features an innovative locking mechanism at the base of its arms, which facilitates easy disassembly—this design simplifies maintenance while improving operational flexibility. Structural integrity was evaluated using the Static Structural module in Ansys Workbench under three operational conditions: no-load, full-load, and extreme-load. Results demonstrate that the airframe meets strength requirements under all conditions, though localized nonlinear deformations were observed in the arms under extreme loads. In response to these findings, the Response Surface Optimization methodology was systematically applied to refine the UAV arm’s design parameters, with the dual goals of minimizing structural mass and reducing displacement. Experimental results show that under the most demanding operating condition, the maximum displacement was reduced by 43.6% compared to the pre-optimization state, while the arm’s weight was reduced by 20.2%. These findings provide critical insights for advancing UAV design, particularly in agricultural and logistics applications that require high payload capacity and robustness.
Huang, KanghuiLi, GuiyingYu, ZhigangYang, JingruWang, YongZhang, Chao
The heating, ventilation, and air-conditioning (HVAC) systems are one of the main factors that contribute to the building’s energy usage. Achieving an effective balance between reducing energy use and maintaining acceptable thermal comfort is the key challenge in conventional HVAC systems. To overcome this challenge, integrating the occupant-centric controls coupled with digital twins into HVAC systems is another potential technique for this effective balance. For this purpose, computational fluid dynamics (CFD) offers the potential, in combination with other surrogate models for real- time applications to enhance the system's performance further. In general, the CFD is applied to investigate indoor airflow/temperature distributions. These are essential for occupant health, comfort, and energy optimisation for the HVAC design state. The objective of this study is to propose an initial step toward building an occupant-centric HVAC digital twin by validating a CFD model of an office against dense in-situ sensing data. The model has been used to resolve airflow and temperature stratification under conventional HVAC operations, using ANSYS Fluent. The boundary conditions have been derived from measured supply parameters, internal gains, and local weather conditions. The results from this study show that the air velocity and temperature at selected durations follow the same trend with low errors, compared to the sensing and measurement data. The model validation from this study establishes the basis for a weather- aware, occupant-feedback digital twin for larger floorplates and multi-zone systems. To achieve the target of the energy and comfort co-optimisation in Industry 4.0-ready buildings, the future work will focus on surrogate modelling to enable near-real-time inference for closed-loop occupant-centric controls, which will directly support dynamic set-point adjustments and multi-zone system ventilation.
Larpruenrudee, PuchaneeHellany, AliFamakinwa, TosinShrestha, SurendraAttwater, RogerCalheiros, Rodrigo Neves
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