Search Results (172)

Aiming at analyzing the load characteristics and friction torque of triple-row hub bearings for new energy vehicles, this work established a comprehensive theoretical and experimental methodology for predicting the internal load distribution and friction torque. Firstly, considering the preload effect via an initial negative clearance, deformation coordination and force balance equations for the triple-row bearing under axial load were formulated, to analyze the external loads under various driving conditions. Based on contact deformation theory, a quasi-static model was developed to combine radial, axial, and moment loads. The Newton–Raphson iterative algorithm was employed to solve the ball load distribution equations, and the correctness was verified by using the finite element method. Furthermore, accounting for the elastic hysteresis, differential sliding, and spin sliding, the theoretical models for friction torque components were established, to investigate the influence of structural parameters and the total friction torque under different driving conditions. Finally, to confirm the effectiveness and the precision of the model, a finite element simulation and experimental measurements of friction torque were conducted, respectively, which showed good agreement with theoretical calculations. The main innovations include proposing a mechanical modeling method for triple-row hub bearings that accounts for preload effects, and establishing an integrated friction torque analysis model applicable to multiple driving conditions. This work provides theoretical support and a methodological foundation for the design of next-generation hub bearings for new energy vehicles. Full article

In large-scale Unmanned Aerial Vehicle (UAV) and task environments—particularly those involving obstacles—dimensional explosion remains a significant challenge in Multi-Robot Task Allocation (MRTA). To this end, a novel heuristic MRTA framework based on Topological Graph Construction (TGC) is proposed. First, the physical map is transformed into a pixel map, from which a Generalized Voronoi Graph (GVG) is generated by extracting clearance points, which is then used to construct the topological graph of the obstacle environment. Next, the affiliations of UAVs and tasks within the topological graph are determined to partition different topological regions, and the task value of each topological node is calculated, followed by the first-phase Task Allocation (TA) on these topological nodes. Finally, UAVs within the same topological region with their allocated tasks perform a local second-phase TA and generate the final TA result. The simulation experiments analyze the influence of different pixel resolutions on the performance of the proposed method. Subsequently, robustness experiments under localization noise, path cost noise, and communication delays demonstrate that the total benefit achieved by the proposed method remains relatively stable, while the computational time is moderately affected. Moreover, comparative experiments and statistical analyses were conducted against k-means clustering-based MRTA methods in different UAV, task, and obstacle scale environments. The results show that the proposed method improves computational speed while maintaining solution quality, with the PI-based method achieving speedups of over 60 times and the CBBA-based method over 10 times compared with the baseline method. Full article

The transition to battery electric vehicles (BEVs) is enabling the significant redesign of key subsystems, including braking systems. This work presents a physics-based optimization framework for the preliminary design of a distributed electro-hydraulic brake-by-wire (DEHB) system tailored for electric vehicles. The DEHB system is modeled as a two-phase actuation process captured through a coupled electro-mechanical and hydraulic model: initial pad–disc clearance closure and subsequent pressure buildup. Sensitivity analysis is employed to identify critical design parameters, and a multi-objective genetic algorithm is used to minimize electrical power consumption, peak current, and maximum torque while satisfying performance constraints. The optimized configuration is benchmarked against commercially available solutions and validated against a multiphysics simulation, showing deviations below 8% for current and power. A dynamic analysis incorporating vehicle-level ABS logic demonstrates the improved performance and energy efficiency of the DEHB system during emergency braking, with a reduction of 50% in required power if compared to a non-optimized system. The results confirm the effectiveness of the proposed method for early-stage sizing and highlight the potential of DEHB architectures in future electric vehicle platforms. Full article

Autonomous-rail Rapid Transit (ART) systems operate on standard roadways while maintaining dedicated right-of-way privileges. Owing to their sustainability, punctual operation, and cost efficiency, ART systems have emerged as a promising solution for medium-capacity urban transit. However, the exclusive lane usage for ART systems frequently leads to inefficient lane utilization, thereby intensifying congestion for non-ART vehicles. This study proposes a moving-block-based lane-sharing strategy for ART with a leading eco-driving approach. First, dynamic lane-access rules are introduced, allowing non-ART vehicles to temporarily use the ART lane without forced clearance or signal coordination. Second, a modified eco-driving trajectory optimization algorithm is constructed on a discrete time–space–state network, allowing the ART trajectory to be obtained through an efficient graph-search procedure while simultaneously guiding following vehicles toward energy-efficient driving patterns. Finally, simulation experiments are conducted to evaluate the impacts of traffic demand, arrival interval, and non-ART vehicles’ compliance rate on system performance. The results demonstrate that the proposed strategy significantly reduces delay and energy consumption for non-ART vehicles by 72.6% and 24.6%, respectively, without compromising ART operations efficiency. This work provides both technical insights and theoretical support for the efficient management of ART systems and the sustainable development of urban transportation. Full article

Background/Objectives: We evaluated Goreisan, a traditional Chinese medicine, for its effects on nephrotic syndrome in a rat model. Methods: Male Sprague–Dawley rats underwent right nephrectomy at 5 weeks of age, followed by adriamycin administration (5 mg/kg) at 6 and 8 weeks of age to induce nephrotic syndrome. At 10 weeks, rats were divided into three groups: vehicle (control), Goreisan 0.5 g/kg (GL), and Goreisan 1.0 g/kg (GH). Goreisan was administered daily for 4 weeks. At 14 weeks, blood, urine, mRNA expressions, and kidney histopathology were analyzed. Data were analyzed using one-way ANOVA followed by Tukey–Kramer post hoc testing. Results: Goreisan prevented worsening kidney function, with reduced glomerular and tubulointerstitial damage, lower systemic and intrarenal 8-hydroxy-2′-deoxyguanosine levels, and lower plasma aldosterone levels and expression of intrarenal renin–angiotensin–aldosterone system (RAAS)-related factors. Urine volume significantly increased in GL and GH groups compared with the control group. In the GH group, urine volume increased markedly (Δ urine volume: 10.0 ± 2.6 mL/day), whereas it tended to decrease in the Vehicle group (Δ urine volume: −1.3 ± 2.5 mL/day). Urine osmolality was lower in the GH group, with a larger decrease in Δ urine osmolality (−616.3 ± 132.8 mOsm/L). These changes occurred without an increase in urinary sodium excretion, suggesting an aquaretic effect independent of natriuresis. Creatinine clearance (CCr/kg) declined markedly in the Vehicle group but was significantly preserved in the GH group (Δ CCr/kg: −2.2 ± 0.19 vs. −0.7 ± 0.28), indicating renoprotective effects. No differences were found in serum arginine–vasopressin levels. Real-time PCR and immunohistochemical staining showed no significant differences in aquaporin (AQP) mRNA expression (AQP1, AQP2, AQP3, and AQP4), but AQP2 localization to the apical membrane in the collecting ducts was reduced with Goreisan treatment. Conclusions: Goreisan demonstrates kidney-protective and diuretic effects in nephrotic syndrome, potentially through reducing systemic oxidative stress, modulating RAAS activation, and altering AQP2 trafficking. Full article

The steering linkage represents a key subsystem of any automobile, playing a direct role in vehicle handling, driving safety, and overall comfort. Within this mechanism, the tie rod and tie rod end are crucial for transmitting steering forces from the gear to the wheel hub. A typical issue that gradually develops in these components is the clearance appearing in the spherical joint, caused by wear, corrosion, and repeated operational stresses. Even small clearances can noticeably reduce stiffness and natural frequencies, making the system more sensitive to vibration and premature failure. In this work, the effect of spherical joint clearance on the dynamic behavior of the tie rod-tie rod end assembly was analyzed through numerical simulation combined with experimental observation. Three-dimensional CAD models were meshed with tetrahedral elements and subjected to modal analysis under several clearance conditions, while boundary constraints were set to replicate real operating conditions. Experimental measurements on a dedicated test rig were used to assess joint clearance and wear in service parts. The results indicate a strong nonlinear relationship between clearance magnitude and modal response, with PTFE bushing degradation identified as the main source of clearance. These findings link the evolution of clearance to the change in vibration characteristics, providing useful insight for diagnostic approaches and predictive maintenance aimed at improving steering reliability and vehicle safety. Full article

This paper proposes a comprehensive framework, Theory–Simulation–Experimental Verification, for the elasto-aerodynamic analysis of elastic foil gas bearings (EFGBs). In contrast to many studies that approximate the foil structure using simplified two-dimensional models, the present work adopts a macro-element beam theory model that incorporates the actual 3D geometry, nonlinear elasticity, and frictional contact effects, and couples it directly with the Reynolds equation. To improve accuracy and robustness, the macro-beam results are validated against a fully coupled fluid–structure interaction (FSI) model developed in COMSOL Multiphysics. Emphasis is placed on quantifying the influence of foil thickness, clearance, and eccentricity, where the pressure distribution, foil deflection, and load capacity are obtained through the coupled solver. The results reveal that increasing foil thickness from 0.1 mm to 0.2 mm elevates the peak gas film pressure from 1.36 × 10⁵ Pa to 1.97 × 10⁵ Pa while simultaneously reducing displacement and pressure fluctuations, thereby enhancing bearing stability. Smaller clearances are shown to increase load capacity but also induce stronger oscillatory flow behavior, indicating a stiffness–stability trade-off. Additionally, prototype experiments with a 0.05 mm clearance confirm practical lift-off at 4300–7000 rpm under 10–30 N external loads, with measured torques of 0.18–0.30 N·m. By combining computational efficiency, 3D fidelity, and experimental validation, the proposed framework provides quantitative guidance for the design and optimization of EFGBs used in high-speed turbomachinery, such as aviation and compact energy systems, including turbine-based air-cycle refrigeration units and small gas-turbine rotors for unmanned aerial vehicles. Full article

Path planning is a critical capability for unmanned aerial vehicles (UAVs) operating in complex 2D environments such as agricultural fields or indoor facilities—scenarios where flight altitude is often constrained and safe, smooth trajectories are essential. While the sampling-based Bidirectional RRT* (BI-RRT*) algorithm offers asymptotic optimality and improved computational efficiency, it frequently generates paths that lack the curvature continuity, obstacle clearance, and low turning angles required for stable drone flight. To address these limitations, this paper proposes a bi-directional rapid exploration random tree algorithm based on cooperative expansion strategy (CE-BI-RRT*) specifically designed for UAVs path planning in cluttered 2D settings. In terms of expansion, for different environments, the algorithm successively tests the direct expansion strategy, the intelligent deflection strategy and the improved artificial potential field method, as these strategies can quickly guide the two trees to the target while avoiding obstacles. In terms of ChooseParent and Rewire, the path length, path smoothness and safety distance are comprehensively considered in the path cost function, and a rotation strategy is applied to make the path away from obstacles after rewiring, so as to realize the gradual optimization of the path. The final path is further refined using a cubic Bezier curve optimization technique to ensure smooth transitions and continuous curvature. Evaluation results confirm its search performance when benchmarked against mainstream randomized motion planning algorithms. Full article

The umbilical cable plays a critical role in deep-sea mining systems by connecting the surface support vessel to the mining vehicle. If the spatial configuration of the umbilical cable is unsuitable for mining vehicle operations, it may experience overloading, slack, seabed contact, or be run over by the mining vehicle. To address these issues, this study focuses on double-stepped, steep-wave, and S-shaped configurations and develops a coupled dynamic model of the surface support vessel–umbilical–mining vehicle system using the lumped-mass method, which incorporates hydrodynamic loads induced by currents and irregular waves, as well as motion excitations from the surface support vessel. The spatial configurations and mechanical responses of three umbilical configurations were evaluated, including maximum effective tension, lateral drift amplitude, and the mining vehicle’s overturning moment. The results indicate that the double-stepped configuration offers superior performance in terms of ground clearance, effective tension, and collaborative operation of the mining vehicle, although it faces an increased risk of fatigue failure due to dual buoyancy sections. The S-shaped configuration exhibits improved control of lateral drift and bending response under ocean current excitation, while the steep-wave configuration demonstrates intermediate behavior. In addition, the study analyzed the local compression of the umbilical cable and the variation trends of the mining vehicle’s overturning moments. These findings offer insights into the optimization of umbilical design and operational parameters, enhancing the safety, reliability, and efficiency of deep-sea mining systems. Full article

Aging plays a major role in the development of numerous chronic diseases, one of which is a marked decline in skeletal health. Beyond diminishing bone mass and strength, mammals of advanced age experience a decline in skeletal mechanotransduction—that is, the ability of the skeleton to respond adaptively to mechanical perturbation. One possibility for the loss of mechanotransduction in bone with aging is an age-associated increase in the population density of senescent cells—those cells that have undergone irreversible cell cycle arrest, resistance to apoptosis, and production of a modified secretome (the SASP) that has damaging effects to nearby healthy (non-senescent) cells. We investigated whether the presence of senescent cells might drive some of the diminished mechanical response observed in aged bone, by testing the hypothesis that the clearance of senescent cells via intermittent senolytic treatment promotes mechanical responsiveness in an aged skeleton. C57BL/6 mice aged 6 months and 22 months were treated weekly with the senolytic cocktail Dasatinib and Quercetin (D + Q) for 1 month, then subjected to low level in vivo mechanical loading of the ulna for 1 week. The 6-month-old mice exhibited a doubling of load-induced ulnar periosteal bone formation when treated with D + Q, compared to vehicle-treated mice, but the periosteal response to loading was not significantly altered by D + Q in the aged (22-month) mice. We further probed the efficacy of D + Q in mechanotransduction by switching to an endocortical model—the axial tibia loading system. Here, the 22-month-old mice had nearly double the load-induced endocortical bone formation compared to vehicle-treated mice. We further assayed the cortical bone gene expression profile in loaded and control tibias from treatment-naïve 6-month and 22-month mice, to determine whether there is significant overlap between mechanically induced signaling genes and SASP genes. We found significant load-induced changes among several SASP genes, suggesting that inhibition of the SASP (i.e., senomorphics) might interfere with mechanical signaling from otherwise healthy cells. In summary, clearance of senescent cells via intermittent D + Q treatment is effective at improving endocortical mechanical responsiveness in the aged skeleton, which is commonly diminished throughout the course of aging. Full article

The traditional intermittent bus lane control struggles to achieve an effective balance between bus priority and lane utilization efficiency. To address this limitation, this study proposes a dynamic control strategy that enables the borrowing of intermittent bus lanes in mixed traffic flow environments and constructs a connected vehicle control model encompassing both the target intersection and its upstream segment. First, a dynamic clearance framework is established on the dedicated lane based on the real-time speed of buses. Concurrently, the target connected and automated vehicle (CAV) predicts the traffic signal status upon its arrival at the stop line to determine its traversable zone at the bus lanes. Subsequently, a coordinated control strategy is designed for the dynamic clearance framework and the traversable zone, leading to the development of lane-changing decision models under four distinct scenarios. This approach allows CAVs to dynamically utilize residual lane resources without compromising bus operations. Finally, using average vehicle delay as the evaluation metric, a comparative simulation analysis is conducted against the traditional bus lane utilization method across four dimensions: connected vehicle penetration rate, traffic flow saturation, right-turn proportion, and bus departure frequency. The experimental results demonstrate that the proposed strategy significantly improves both bus priority and overall traffic efficiency. Full article

Traffic incident management (TIM) practices have been widely demonstrated to reduce congestion and secondary crashes. TIM performance measures have evolved over the years and have been a critical tool for agencies to benchmark their operations and identify opportunity for improvement. This paper discusses how the deployment of incident resources can be tracked to improve the fidelity of those performance measures to help guide their TIM program management. Specifically, the paper focuses on integrating a new TIM reference point that identifies when all necessary recovery resources are on scene (T_4,ANRR)_. The value of this reference point is explained through four detailed case studies, and the ability to tabulate this value at scale is demonstrated for 128 incidents. Subsequently, statistics from 128 incidents are presented. Median recovery resource mobilization time for car crashes, semi crashes, car fires, and semi fires were 32, 42, 45, and 66 min, respectively. However, the upper quartile values for those same types of incidents increased to 55, 66, 69, and 105 min, respectively. Of particular note, the paper demonstrates the importance of careful proactive planning for response resources on incidents involving large vehicles that require significant recovery resources and how those response times extend incident clearance times. Tracking T_4,ANRR is a first step toward identifying training and perhaps incentive programs to mitigate delays in obtaining all of the needed recovery resources on scene. Full article

This study explores and evaluates different methodologies for designing the edge-of-traveled-way turning paths at right-angle at-grade intersections, with emphasis on low-speed maneuvers involving large design vehicles. Three geometric approaches are examined as follows: the standard AASHTO configuration, the German RAS-K-1 triple-radius method, and a clothoid-based transition curve design. Simulations using representative design vehicles, conducted under speeds ≤ 15 km/h, are used to assess each method’s performance in terms of spatial efficiency, steering continuity, and lateral clearance. The findings suggest that while the AASHTO asymmetric compound curve offers an effective balance between clearance and compactness, clothoid curves may improve transition smoothness and provide an alternative option for designing the edge-of-traveled-way turning paths at right-angle at-grade intersections. Full article

This study examines the modernization of the 61-4179 TVZ passenger coach for transporting light automobiles up to 3 tons, addressing the efficiency of multifunctional rail use. The objective was to assess how additional mass–dimensional loading influences strength, load distribution, and the dynamic stability of the vehicle–track system. Finite element simulations in ANSYS Workbench 2021 R2 determined stress distribution, deformations, and safety margins, while multibody dynamics modeling in Universal Mechanism evaluated wheel–rail contact forces, carbody accelerations, and stability coefficients. Field tests on curves with radii of 350 m and 300 m at 60 km/h validated the models. Carbody accelerations were 0.65–0.68 m/s², below the 0.7 m/s² regulatory limit; wheelset attack angles remained under 0.01 rad; and derailment safety coefficients were 1.6–1.8, all meeting international standards. Uniform load distribution maintained stability and suppressed oscillations. However, critical scenarios (wheel wear, extreme flange clearance, higher speeds) produced parameters approaching threshold values. To mitigate risks, clearance adjustment per δ₀ standards, a 1:20 guard-rail inclination, and optimized crossing profiles are proposed. These measures reduced lateral dynamic forces by 12–15% and raised the strength coefficient by 1.2–1.3. The results confirm technical feasibility, operational safety, and extended service life, supporting sustainable multimodal transport development. Full article

Path planning for unmanned aerial vehicles (UAVs) in mountainous environments requires satisfying terrain clearance and obstacle avoidance constraints while optimizing path length, flight time, and energy consumption. To address these challenges, this paper proposes EC-MOPSO (Epsilon-dominance and Crowding-distance-based Multi-Objective Particle Swarm Optimization). Inspired by the principle of symmetry, the algorithm integrates an adaptive parameter adjustment mechanism with a $\epsilon -$ dominance–crowding archiving strategy to balance global exploration and local exploitation through spatially symmetric archive management. A safety-repairable B-spline trajectory model ensures smooth and feasible flight paths under complex terrain conditions. Simulation results show that EC-MOPSO reduces path length by 10–40%, improves normalized hypervolume by over 25%, and decreases performance variance by 20–25%, confirming faster convergence and higher robustness compared with representative multi-objective optimization approaches. Ablation studies further verify that both the adaptive parameter mechanism and the $\epsilon -$ dominance–crowding strategy significantly enhance convergence stability and overall optimization performance. Overall, EC-MOPSO provides an adaptive and reliable optimization framework for generating efficient, safe, and energy-aware UAV trajectories in real-world mountainous rescue missions. Full article