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This method outlines the standard procedure for testing the hardness of bearing components. Bearings covered by this test method shall be any rolling element bearing used in airframe control.
ACBG Rolling Element Bearing Committee
This SAE Aerospace Recommended Practice (ARP) provides criteria for the design, installation, operation, and training aspects of head-up display (HUD) systems in transport category aircraft, with emphasis on pilot interface and operational requirements. The recommendations apply to permanently installed (including stowable) HUDs that display primary flight information, including those integrating enhanced flight vision system (EFVS) imagery. The intent is to ensure HUDs are designed and used in a manner that improves pilot situational awareness and flight technical performance across all phases of flight, up to and including low-visibility operations. While technical design standards (optical performance, hardware specs, etc.) are defined in documents like ARP5288 and AS8055, this document focuses on pilot usage considerations and human factors. HUD systems addressed here are typically designed to support a fail-passive operational concept applicable to Category III instrument approach
S-7 Flight Deck Handling Qualities Stds for Trans Aircraft
The intent of this specification is for the procurement of carbon fiber epoxy prepreg product with 250 °F (121 °C) cure for aerospace applications; therefore, no qualification or equivalency threshold values are provided. Users that intend to conduct a new material qualification or equivalency program must refer to the production quality assurance section (see 4.3).
AMS P17 Polymer Matrix Composites Committee
Causal reasoning is the task to identify causal relations between a pair of events in a given context. However, causal reasoning in natural language remains a challenging task for large language models (LLMs), since they tend to mix correlation and causality and exhibit bias in their reasoning, especially by mistaking temporal proximity for causal relations. The problem is exacerbated by the models’ propensity to generate spurious justifications that confuses co-occurrence rather than actual causal relationships. Although CoT prompting has shown effectiveness in enhancing multi-step reasoning, it is prone to hallucination and spurious inferences, which generally dampens their capability to provide correct causal explanations. The variant of CoT, CoT-SC, is a more promising attempt at yielding consistent outputs by randomly sampling multiple reasoning paths, and voting for the most probable answer. However, for its implementation, CoT-SC also demands expensive computations. The
Yang, JiaoyunQi, BotaoLiu, LiLi, LianAn, Ning
Surface electromyography (EMG) signals are essential for facilitating intuitive interactions between humans and bionic hands. However, their inherent non-stationarity, low signal-to-noise ratio, and significant inter-individual variability present considerable obstacles to precise decoding. To overcome these challenges, this study proposes a novel recognition framework combining wavelet packet decomposition and a dynamic graph convolutional-Transformer model. The process starts with multi-layer wavelet packet decomposition and adaptive threshold denoising, effectively removing noise while retaining critical signal features. Subsequently, a dynamic graph convolutional network is employed to capture spatial interactions among multi-channel electrodes, and a Transformer encoder models long-term temporal dependencies within the signals. By integrating these methods, the model generates a fused feature representation that incorporates both spatial and temporal correlations. Experimental
Huang, RuiZhao, YueYang, PenghuaZhu, JintaoXiong, Xibei
The design process of mining supports is often complicated due to their intricate structure and numerous dimensional dependencies, leading to a cumbersome modeling process and low design efficiency. To address these challenges, this paper introduces a parametric design system for mining supports built on the SolidWorks platform. The system integrates modular design concepts, module-matching principles, dimension-driven techniques, and API development. By adopting a modular assembly modeling approach, the system offers an efficient solution for managing the dimensional relationships between the various components of mining supports. Additionally, the system supports adaptive processing of 2D engineering drawings, facilitating the rapid design and manufacturing of mining supports. Engineering case studies demonstrate that this system enhances the design efficiency of mining supports by over 90%, significantly shortening the product development cycle, ensuring product quality, and
Rui, LichaoSong, JiahaoYang, ZhiqingLi, HelongDing, Lijian
This study addresses data loss in photovoltaic (PV) power generation systems resulting from factors such as adverse weather and sensor failures. To obtain more accurate and reliable PV data, we propose a data imputation method based on a Bidirectional Long Short-Term Memory Generative Adversarial Network (Bi-LSTM-GAN). In this model, the Generative Adversarial Network (GAN) serves as the overarching framework, while the Long Short-Term Memory (LSTM) and its bidirectional variant, the Bidirectional Long Short-Term Memory (Bi-LSTM), form the core components for learning and reconstructing missing data sequences. The key innovation of this method lies in replacing the traditional fully connected layer in the GAN with a Bi-LSTM-based architecture, which enables the model to effectively capture the latent temporal information in PV power generation data. The temporal correlation module is designed to capture the temporal dependencies and the characteristics of event series. Furthermore, by
Shi, ZhuangRen, ManmanDing, Lei
To enhance the safety and efficiency of power batteries for new energy vehicles, a high-fidelity thermal management simulation model for lithium-ion batteries was established using a multi-scale coupled approach encompassing "cell-module-pack" levels. Charge/discharge experiments within the 15–45°C temperature range and under various State of Charge (SOC) conditions were conducted to obtain cell characteristic parameters. A second-order RC equivalent circuit model was constructed and validated. A three-dimensional thermal model of the battery pack was developed using the NX and STAR-CCM+software platforms and validated through high/low-temperature humidity tests. Results indicate that simulation errors for battery pack temperature and cooling line pressure were both below 3%. The model accurately simulates thermal behavior from microscopic cell characteristics to macroscopic battery pack dynamics.
Luo, ZhaoyangSong, Lan
Active collision avoidance methods are crucial components of vehicle active safety systems, which can effectively prevent collisions or mitigate collision-induced losses. To address the limitations of existing methods, particularly their insufficient foresight in dynamic traffic environments, this paper proposes an active collision avoidance control method based on driving intention recognition and an improved Driving Safety Field (DSF) model to enable more proactive and stable collision avoidance. First, a Hidden Markov Model (HMM) is trained using vehicle trajectory data from a public dataset to accurately identify the driving intentions of the obstacle vehicles, including Lane Change Left (LCL), Lane Keeping (LK), and Lane Change Right (LCR). Then, an improved potential field model is established, which incorporates vehicle acceleration to more comprehensively quantify the driving risk faced by the host vehicle within the DSF model framework. Subsequently, an active collision
Pan, YuxiangChen, JinWang, HaitaoBai, Xianxu
With the rapid growth of renewable energy sources such as photovoltaics, energy storage systems, and wind power, hybrid AC/DC microgrids (H-MGs) are gradually emerging as a key technology for achieving efficient interconnection between generation units and load demands. However, issues such as communication delays, unequal power sharing, and the restoration of voltage and frequency in hybrid microgrids have posed serious threats to the stable operation of microgrids. We also need to appropriately adjust the simulation parameters to ensure that the proposed control framework maintains sufficient flexibility under different load conditions and achieves high operating efficiency in simulation. To tackle these challenges, this paper proposes a distributed secondary control strategy grounded in coordinated consensus and combined with droop-based interlinking converters (ICs) to realize power coupling between the AC and DC subgrids. The proposed method enables precise active-power sharing
Yu, PeijieZhang, FanghaiSun, WeiYuan, WeiboPeng, Bo
To address the issues of battery overcharge damage caused by voltage imbalance and excessive grid-connected inrush current when high-rate charge-discharge energy storage batteries are connected to the DC side of cascaded energy storage converters, this paper proposes a three-stage pre-charging control strategy considering battery characteristics. This strategy achieves rapid charging and voltage balancing control of energy storage modules through the orderly connection of three stages: “uncontrolled rectification - sorting and voltage balancing - balancing maintenance”. In the first stage, an uncontrolled rectification method with series soft-start resistors is adopted to reduce the inrush current at power-on. In the second stage, based on the FPGA parallel full-comparison sorting algorithm, the DC-side voltage of each sub-module is quickly balanced by switching sub-modules. In the third stage, the number of fixed sub-modules to be cut off is maintained to continuously optimize the
Gu, CongWu, RuiZhou, WenCai, WenjieTian, YunxiangYang, Zhiqing
While large language models (LLMs) offer a convenient natural language interface for logistics optimization problems, it remains challenging to directly generate reliable mathematical models and executable code from unstructured text requirements. LLMs tend to produce invalid constraints or syntactically incorrect code. In addition, traditional logistics optimization methods lack the flexibility to adjust warehouse rules or operational goals without manual expert intervention. To address these issues, we propose LOOP (a Language-Model Orchestrated Optimization Pipeline), which automatically translates natural-language requirements into optimization algorithm code while retaining the rigor of classical models and solvers. LOOP leverages task-specific agents to construct accurate mathematical models and adopts a difference-driven code generation approach. First, it synchronizes model changes into executable code via semantic mapping and ensemble difference analysis. Second, it
Ding, RuiqingLi, QianyingLi, Xiaojian
Although carbon fiber-reinforced aluminum-lined hydrogen storage vessels (Type III) exhibit outstanding specific strength and specific stiffness, the constraints imposed by their design parameters on fatigue performance and ultimate load-bearing capacity remain incompletely elucidated. We propose a fatigue life prediction method for high-pressure vessels that couples progressive damage in the fiber composite with cumulative damage in the metallic liner, aimed at forecasting the fatigue performance of Type III pressure vessels under cyclic loading. Furthermore, a finite element analysis systematically investigates the influence of key design parameters, for nominal pressure, liner diameter and liner thickness, on fatigue performance and ultimate load-bearing capacity. Results indicate that fatigue life significantly decreases with increasing nominal pressure and liner diameter, with nominal pressure exerting a more pronounced effect. Notably, altering the autoclave pressure alone cannot
Bi, ZhihaiZhang, Qian
The rapid development of autonomous driving technology has brought emerging opportunities to optimize the omnidirectional vehicle driving performance. However, its compliance with driving habits directly determines its social acceptance. Therefore, how to balance consistency between performance improvement and driving habits has become an important bottleneck restricting the rapid promotion of autonomous driving technology. Manual driving vehicles mostly focus on the safety of both longitudinal and lateral movements, and cannot cope with the vertical movement, let alone the performance of economy, comfort, and efficiency. In this context, this paper proposes an anthropomorphic trajectory optimization method incorporating vehicle omnidirectional dynamic characteristics and corresponding driving habits. Firstly, this paper explores vehicle dynamic characteristics in longitudinal, lateral, and vertical directions, and reveals the coupling effect of motion states during driving
Liao, PengZhang, DefengNing, DonghongLi, SijiaWang, Tao
Currently, with the continuous development of electric vehicles, DC microgrids have attracted widespread attention due to their flexible access methods and high energy transmission efficiency. However, since the distributed secondary control of DC microgrids relies on information exchange through communication networks, false data injection (FDI) attacks on these networks may cause control algorithms to fail, leading to voltage deviations, output current imbalance, and in severe cases, system instability. This study focuses on DC microgrids based on parallel DC–DC buck converters and proposes a distributed secondary control strategy based on a sliding mode observer to address FDI attacks. By treating the system's FDI attack signals as an extended state, an extended sliding mode observer is designed to track the attack signals. Based on the observed attacks, a control algorithm is proposed that compensates the control inputs through the observer, ensuring proportional sharing of bus
Sun, WeiChen, JingYu, JinzhuYuan, WeiboPeng, BoLin, Fei
This paper presents the design of a novel intelligent monitoring platform for low and medium altitudes, aiming to offer a new solution for the development of intelligent equipment operating in this airspace. Current monitoring tasks are primarily performed by fixed-wing and multi-rotor UAVs, but these platforms face significant technical bottlenecks in flight endurance and monitoring precision. This research aims to address these deficiencies. The platform is based on a small-scale unmanned airship featuring a semi-rigid, hybrid lift-body structure. Improvements were made upon the traditional ellipsoidal hull; the hull profile was optimized using a geometric superposition method, introducing an aerodynamic camber line with a maximum camber (m) of 4% to enhance aerodynamic performance at small angles of attack. In terms of its energy system, the platform is powered by a purely electric energy system composed of solar panels and batteries; solar energy is used during the day, while
Song, ZiangGao, WenxuanCao, XiaochuanZheng, XingZhao, Chong
This article focuses on the problem of high labor cost, low processing efficiency and poor automation of the existing equipment in the postharvest processing of Chinese cabbage. It will design and produce an automated Chinese cabbage processing method called Smart Fresh Pack. Root removal, leaf removal, washing, loading, weighing, packaging and labeling functions were integrated, and smart dexterous intelligence was applied to core concepts and this can be used in the bulk production scenario of supermarkets in the city and countryside Compared with traditional assembly line equipment, obvious advantages in terms of structure, function and processing capacity: Key innovations include: Low-pressure air jet cleaning replaces water washing, which prevents a second contamination and weighing error due to surface moisture; pneumatic gripper and multi-DOF robotic arms combine to package and dynamically weigh simultaneously, streamlining these tasks; machine vision relies on an SSD
Chen, YuhuiZhang, YixuanRuan, JiaZhu, HuayunHe, LianzhengZhao, Ping
Robotic ultrasound scanning technology is a research hotspot in the field of medical imaging, and can achieve standardized and high-precision data acquisition. However, large force tracking errors occur during scanning, especially in complex human tissues, which can severely degrade image quality and diagnostic accuracy. Therefore, we propose an adaptive speed-regulated impedance control strategy to address this challenge, which innovatively combines the spline real-time interpolation and impedance control for constant force tracking. Firstly, the discrete ultrasound scanning paths are fitted to generate a smooth and synchronized interpolation trajectory. Then, the speed of the reference trajectory is adjusted in real time based on the Taylor formula to reduce the force tracking error. Experimental verification was conducted, and the results showed that the force tracking error increases with the increase of trajectory speed. In addition, at high speeds (e.g., 10 mm/s), the mean
Min, KangZhang, LeShi, YudongFang, JinMo, HangjieLi, Xiaojian
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Huang, DeLu, JiaweiYang, ZhiqingXv, ZiyiXing, Hui
Aimed at the high energy consumption for battery heating of a light hybrid truck in low-temperature winter, this paper proposes an optimized battery thermal management scheme based on motor waste heat and PTC cooperation. Then it verifies its energy-saving performance based on multi-condition simulation and testing. Taking the constant-speed condition at -5°C as an example, firstly, the accuracy of the battery thermal management model is verified by comparative simulation and test. Then, based on the verified model, the battery thermal management model is simulated under typical winter conditions at 0°C and 5°C. The analysis results show that, when the battery temperature is raised from the initial state to a certain target, the energy consumption of the motor waste heat-assisted PTC heating scheme is obviously less than that of PTC heating. The energy saving rates are 33.137% at -5°C, 32.45% at 0°C, and 32.56% at 5°C, respectively. The research results have proved that the effective
Meng, ShunZhang, DongZhang, YuZhang, ChunyuYao, MingyaoQiu, LiangQian, Yejian
With the continuous economic development and the rapid advancement of urbanization, the stable operation of distribution networks has become a key factor in ensuring the reliability of power systems. In response to the problems of high risk, high labor intensity, and low efficiency in distribution network operations, this paper designs an auxiliary operation mechanical arm for distribution networks. This auxiliary operation mechanical arm is fixed on the working bucket of an insulated boom truck. The main body is a two-degree- of-freedom SCARA mechanical arm that moves in a plane, and the end is connected to a three-degree-of-freedom end effector through a flange to cooperate in completing the pitch, deflection, axial feed, and clamping of insulated rods, achieving coarse positioning in the plane and precise positioning of the target. The auxiliary mechanical arm operation platform adopts a fully insulated design. The platform is made of glass nylon material, and the edges are rounded
Wang, JingjieChen, ZhenningFeng, YuWu, ShaoleiZhang, YuxiDou, HangWang, Wei
Identifying driving heterogeneity is critical for enhancing the strategy learning capabilities of autonomous driving systems, as well as improving their safety and efficiency. This research proposes a novel driving heterogeneity identification framework. The framework consists of three core processes: action phase extraction, action relationship modeling, and behavior heterogeneity identification. First, a rule-based segmentation method is employed to systematically decode and interpret the inherent variations in human driving behavior. Subsequently, an action relationship modeling method is introduced to characterize the temporal relations between the acquired action phases. Finally, to mitigate the inaccurate identification caused by the sparse distribution of critical driving events in long-sequence data, a semantic encoding method is applied to remap the driving behavior space. Experimental results on the Lyft level-5 dataset validate the effectiveness of the proposed framework
Yin, HuiZhang, QinyaoLi, XiaojianMo, Hangjie
End-to-end autonomous driving in urban environments faces three core challenges. First, camera and LiDAR sensor heterogeneity causes cross-modal perception inconsistencies and sensor fusion instability. Second, diffusion models suffer from training instability due to scale variance and distribution changes, which limits generalization. Third, traditional trajectory decoders lack structured interaction with semantic elements, thereby undermining planning rationality. To address these issues, CMFPNet introduces an integrated framework with three key modules. The HGCF-Backbone integrates LiDAR and camera features using channel focus, deformable cross-focus, and state space modeling to enhance semantic alignment. The NST module maps physical trajectories to normalized space, employing truncated diffusion sampling for stable generation in just 2–4 steps. The NDA models trajectory generation as a semantic narrative, utilizing a six-stage semantic attention flow incorporating BEV context
Qu, YanweiMo, Hangjie
As the “digital brain” and core foundational support for the development of intelligent transportation and connected vehicles, the performance of data centers directly determines the operational capability of intelligent transportation systems. In the process of advancing the vehicle-road-cloud collaborative architecture, the demand for high-performance computing power in data centers has experienced explosive growth. The substantial increase in computing tasks has posed severe challenges to thermal management, making efficient and reliable cooling systems an indispensable core component. Centrifugal compressor water-cooling units are the mainstream cooling solution for large-capacity scenarios, and their design optimization is crucial for improving the energy efficiency and performance of the entire cooling system. This paper proposes a one-dimensional performance prediction method for centrifugal compressors based on an empirical loss model, and realizes the iterative calculation of
Zhu, MinhaoJiang, BinLi, MinZeng, ZihuiGu, Yunhui