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Aiming at the core problems of abrupt changes in dynamic characteristics and poor smoothness in mode switching during the cross-medium operation of amphibious wing-in-ground (WIG) craft, this paper develops an intelligent switching and control system based on multi-sensor fusion. The system integrates measurement data from the Global Navigation Satellite System (GNSS), Inertial Measurement Unit (IMU), and Light Detection and Ranging (LiDAR) to construct a state observation module for mode switching decision-making. On this basis, a fuzzy switching logic centered on flight altitude and sea state characteristics is proposed, and a hybrid control strategy combining Linear Quadratic Regulator (LQR) and Proportional-Integral-Derivative (PID) is designed to realize the smooth transition between water surface and flight modes. Numerical simulations conducted in Python demonstrate that the proposed control scheme can accurately determine the mode switching timing, stabilize the pitch angle fluctuation within ±3° during the transition process, and effectively enhance the ability of WIG craft to operate autonomously and stably of the WIG craft in complex sea conditions.
Zhang, Qihao, Yan, Yifei, Cao, Fengshuo, Xiong, Yueling, Liu, Qing, Deng, Yanpeng, Wu, Peng
The prediction of air target trajectories is important. It is necessary to integrate time-series data in the motion of air targets, such as timestamps, spatial coordinates, kinematic parameters, etc. To cope with the challenges of air target trajectory prediction in complex electromagnetic environments, this paper proposes the MSDTransformer model. The SMSAE and DDE modules are introduced, and this method improves the performance of air-target trajectory prediction. The sensitivity analysis of system hyperparameters verifies the rationality of model parameter configuration. The experimental results show that, among the simulated air target data, MSD-Transformer achieves lower prediction errors and demonstrates strong overall performance, compared with 5 main methods (iTransformer, Informer, PatchTST). It can support the understanding and prediction of target situations, provide an accurate basis for the analysis of the intentions of air targets and the prediction of the evolution of situation evolution, and then improve the situation awareness ability. It has important application value for trajectory prediction in modern aerospace surveillance and situation awareness.
Zhang, Yongzhuang, Sun, Peng, Zhang, Jieyong, Yang, Guangwei, Jiang, Jianxiong, Li, Tianxin, Zhong, Yun
In space gravitational wave detection, the verification of the mass release capture phase determines subsequent mission advancement. Existing control algorithms are primarily validated through simulation, though ground-based experimental verification remains indispensable. This paper develops a two-stage torsion pendulumbased ground hardware-in-the-loop (HIL) simulation system to simulate and verify the position and attitude degrees of freedom of the test mass. An Expansive State Observer and State Feedback Control (ESO-SFC) disturbance rejection and capture controller based on an ESO and SFC was designed and compared with a PID controller. Numerical simulation results demonstrate that the ESOSFC controller outperforms the PID controller. Experimental validation was conducted on a HIL simulation system. Results confirmed the system's capability to achieve capture functionality while validating the effectiveness of both the ESO-SFC and PID control algorithms. The ESO-SFC demonstrated superior control performance to PID, with experimental outcomes consistent with simulation results. This provides a reference for test mass release capture control algorithms.
Ping, Shanyan, Ren, Yuqi, Cui, Bing, Zhang, Chu, Xia, Yuanqing, Duan, Li, Kang, Qi
In response to the challenges of autonomous obstacle detection and landing site selection during the soft-landing approach phase of the Chang'e probes, this paper proposes a method based on Fractal Brownian Motion (FBM) for local lunar terrain reconstruction and obstacle identification. Using passive optical imagery and incorporating statistical models of crater morphology and distribution, the method approximates the 3D structure of candidate landing areas and estimates local slopes. Combined with texture analysis (TA) via K-means clustering evaluated by silhouette coefficients, and by integrating slope and roughness metrics, feasible landing zones are autonomously identified. Simulation results demonstrate that the proposed approach can rapidly reconstruct terrain and select suitable landing areas, showing good mission adaptability.
Zhu, Hanxi, Wu, Peng, Wu, He, Li, Yixiu, Tang, Weipeng, Deng, Yanpeng
This paper investigates the design problem of a fusion filtering algorithm for nonlinear networked rectangular descriptor systems with multi-source information. A set of independent Bernoulli random variables is introduced to characterize the phenomenon of denial of service (DoS) attacks, where the attack probability consists of a nominal probability and an uncertain term with a known upper bound (UB). Firstly, a full-order transformation method is introduced to transform the rectangular descriptor system into a non-descriptor system, where the local filters are constructed. Then, by employing the elementary inequality, the upper bounds on both the prediction error covariance and the filtering error covariance are derived and characterized by matrix difference equations. The local filter gain is designed by minimizing the obtained UB of the filtering error covariance. Subsequently, based on the covariance intersection fusion rule, a new fusion filtering algorithm is presented for addressing the descriptor system. Lastly, the effectiveness of the proposed algorithm is verified through a simulation experiment.
Feng, Qiushi, Zhang, Wenxin, Luo, Ruonan, Hu, Jun, Wu, Zhihui
Time series forecasting is a practical cornerstone for decision-making in diverse fields including finance, energy management and meteorology, yet conventional Transformer-based models are plagued by high computational complexity inherent in their attention mechanism, as well as poor efficiency in capturing long-range dependencies when processing long-sequence time series data. Meanwhile, the recently proposed Mamba model built on a linear-complexity state space model has achieved strong performance in long-sequence modeling tasks, but the vanilla Mamba model still has obvious limitations in time series forecasting scenarios, including insufficient discriminability of channel features, unsatisfactory prediction accuracy, and information loss during feature transmission in the encoder layer. To address these issues, this paper proposes An Enhanced Mamba Integrating Dynamic Compression Ratio Channel Attention and Progressive Projection for Multivariate Time Series Forecasting, which incorporates three core improvement strategies: a lightweight dynamic compression ratio channel attention, a residual-optimized encoder, and a progressive prediction head. These strategies realize adaptive weighting of channel features, lossless information transmission in the encoder and gradual refinement of forecasting results respectively. Extensive experiments on multiple public time series datasets show that compared with the vanilla Mamba model and mainstream Transformer-based forecasting methods, the proposed model achieves significant improvements in prediction accuracy, along with stronger robustness and higher practical application value.
Zhu, Yongdong, Zou, Lei, Li, Na, Wang, Chenxi
This paper presents GBC-YOLOv5s, a lightweight vehicle detection model designed for unmanned aerial vehicle (UAV) applications in the growing low-altitude economy sector. By utilizing the baseline YOLOv5s architecture, we integrated three structural enhancements to achieve an optimal trade-off between algorithmic precision and processing expenses. First, ghost convolution is used to exploit feature map redundancy, substantially cutting both parameter count and computational overhead. Second, a Bi-Level routing attention (BRA) mechanism is integrated. This allows the model to capture global context along with fine-grained local features of vehicle targets effectively. Third, standard upsampling is replaced with content-aware reassembly of features (CARAFE). This better preserves feature details, which proves particularly important for detecting small objects. Testing was conducted on a custom UAV-based vehicle dataset. GBC-YOLOv5s achieves 86.6% average precision (AP) with only 4.7 M parameters. This represents a 34.7% reduction from the original YOLOv5s with 7.2 M parameters. The accuracy drop is merely 0.2%. Ablation experiments validate both the individual impact and synergistic nature of each proposed module. Results show that GBC-YOLOv5s reaches a practical balance between performance and efficiency. It offers a workable solution for real-time vehicle detection on resource-limited UAV platforms and intelligent traffic monitoring applications.
Zhang, Qingpei, Yu, Tianhao, Zhao, Zheming
The research concentrates on the Gaussian approximation fusion filtering (GAFF) issue for multi-sensor nonlinear systems under Markov denial of service (DoS) attacks. This paper aims to propose a fusion filtering algorithm for the addressed systems to cope with DoS attacks within the Gaussian approximation filtering framework, where the attacks follow the Markov property. In particular, a prediction compensation strategy is adopted to reduce the impact caused by the attacks as much as possible. In light of the available measurements, the Gaussian approximation local filtering unified framework is given, where the Gaussian weighted integrals are addressed by means of the cubature Kalman method. By using the sequential inverse covariance intersection fusion criterion, the GAFF algorithm is obtained to improve estimation accuracy. Finally, a simulation experiment with comparison tests is introduced to validate the effectiveness of the proposed GAFF method.
Luo, Ruonan, Hu, Jun, Jia, Chaoqing, Dao, Wen
This study investigates the coupling effect between rotating components of a satellite equipped with flexible appendages and the satellite’s unconstrained modes. A modal synthesis method based on mixed coordinates is adopted to establish the dynamic model of a satellite with multiple flexible appendages. The vibration equations under the excitation of disturbance torques induced by rotating components are derived for the flexible appendages in an unconstrained state. The on-orbit unconstrained modal frequencies and their mode shape vectors are calculated. Based on this, the analytical expressions for the satellite’s unconstrained modal responses and attitude angular velocity under the influence of driving disturbances from rotating components are obtained. Furthermore, the coefficient matrix that characterizes the amplification of attitude angular velocity induced by flexible vibration is analyzed when the drive frequency of rotating components is coupled with the satellite’s unconstrained modal frequencies. Taking a sun-synchronous orbit satellite with a single solar array as an example, the on-orbit unconstrained modal frequencies as a function of solar array angles are calculated. By applying harmonic disturbance torque generated by a rotating component, the attitude angular velocity and constrained modal coordinates are obtained through simulation. When the drive frequency of the rotating component matches the satellite’s unconstrained modal frequency, the corresponding mode shape (eigenvector) is analyzed. Based on the eigenvector values, the constrained mode of the solar array exhibiting the maximum coupling vibration is identified. The amplification coefficient matrix of attitude angular velocity resulting from coupling with the drive disturbance of the rotating component is validated. The damping coefficient associated with the unconstrained mode is estimated using the simulation data.
Sun, Shang, Niu, Wenting, Zhang, Kaicheng, Yang, Yulong, Zhang, Yanzhao
With the continuous advancement of collaborative unmanned aerial vehicle (UAV) swarm applications, the importance of intent recognition for aerial swarms in UAV management and control has become increasingly evident. To address the shortcomings of existing intent recognition methods, this paper proposes a knowledge-driven aerial swarm target intent recognition method designed for few-shot scenarios. First, a target trajectory clustering algorithm is designed by combining trajectory similarity measurement (which considers directional features) with density peaks clustering. This algorithm groups targets exhibiting the same or similar motion trends, thereby transforming the swarm target intent recognition problem into a swarm member intent recognition problem, which reduces the complexity of intent recognition. Second, considering the behavioral dynamics inherent in aerial swarm collaborative applications, a target intent inference model is constructed based on a Dynamic Bayesian Network (DBN). Utilizing the characteristic information of swarm targets at different time points, this model achieves intent inference and recognition through a hierarchical process: “sub-intent inference → accumulation of historical sub-intent sequences → intent inference.” Finally, simulation experiments are conducted to verify the feasibility and effectiveness of the proposed method.
Jiang, Jianxiong, Gui, Yang, Sun, Peng, Yang, Xinyu, Yang, Guangwei, Zhong, Yun
Low Earth Orbit (LEO) remote sensing satellites exhibit significant limitations in emergency response operations, primarily due to the constraints of orbital mechanics and a traditional reliance on ground-involved, open-loop operational models. Current response latencies often span several hours, rendering acquired data less effective for disasters with rapid temporal dynamics. We propose a new intra-pass autonomous reaction application mode to solve this key problem in emergency response. We build the mode on an agile satellite platform operating in an 800 km sun-synchronous orbit. We equip the platform with two core sensors through an innovative design. The two sensors are an optical camera with 0.5-meter resolution and a forward-looking infrared camera. The infrared camera has a 600-kilometer swath and a 10-meter nadir resolution. We take onboard artificial intelligence technologies as the research core. The technologies support real-time and autonomous analysis of forward-looking infrared image data. This analytical capability facilitates the real-time detection and autonomous confirmation of stochastic events, such as wildfires, by leveraging onboard artificial intelligence (AI) to perform real-time analysis of IR imagery. This subsequently triggers immediate autonomous re-tasking for high-resolution follow-up observation within the same orbital pass. We establish an optimization model for the satellite system. The model is used to solve the key balance problem between the sensor forward-looking angle, achievable reaction time, and actual detection resolution. We conduct a detailed engineering time budget analysis for the whole satellite operation system. Analysis results show that a specific forward-looking angle must be set for the infrared camera to obtain a 70-second autonomous response window of the satellite. The 70second window contains 30 seconds for AI cognitive analysis, a maximum of 33.6 seconds for platform attitude maneuvering, and 10 seconds for platform stability adjustment. The minimum forward-looking angle required for the infrared camera is about 33.6 degrees. The ground sampling distance of the infrared camera will decrease to 12.2 meters at this angle. The resulting 12.2-meter ground sampling distance (GSD) remains sufficient to meet the practical requirements of early-stage detection. The proposed Intra-Pass Autonomous Reaction (IPAR) mode reduces emergency response times from hours to seconds, significantly enhancing the proactive observation capabilities of LEO platforms.
Qiu, Hu, Zhao, Xinwei, Liu, Dongfusheng, Wang, Honghai
Series hybrid tiltrotor aircraft operate under highly dynamic and multi-phase flight missions. This paper addresses the resulting energy management challenge. Moving beyond the direct application of existing optimization algorithms, this study proposes a novel codesign framework that synergizes offline global optimization with online fuzzy adaptive control. The key theoretical innovation lies in transforming the online, real-time optimization problem of determining the optimal equivalent factor into an offline global optimization problem for the parameters of a fuzzy-PI controller. This is achieved through a hybrid particle swarm optimization and genetic algorithm (PSOGA), which optimizes the controller's scaling factors and gains. The optimized controller embeds mission-level economic information into the online generation of the equivalent factor, so that the power-split decision is determined not only by the instantaneous operating conditions, but also by the overall economic objective of the mission. Simulation results under typical and stochastic flight conditions validate the framework's effectiveness. Compared to benchmark strategies, the proposed PSOGA-Fuzzy-A-ECMS achieves a 6.7% improvement in fuel economy while robustly maintaining the battery state of charge within a safe and stable range. This study provides a systematic and theoretically-grounded design paradigm for real-time energy management in complex, time-varying systems.
Wang, Zhihao, Wang, Xiangyang
In traditional multi-unmanned aerial vehicles (UAVs) cooperative strategies within complex irregular regions, the low coverage efficiency, boundary constraint failure, and insufficient robustness bring the challenges. This paper proposes a cooperative search-andattack algorithm, which integrates adaptive mission area discretization and distributed intelligent particle swarm optimization (DIPSO). An adaptive grid model is constructed with ray casting algorithm to discretize arbitrary polygonal mission areas precisely. It can effectively reduce the invalid searches in non-mission zones by abandoning the traditional rectangular assumption. Moreover, a multi-objective fitness function (MOFF) is designed by incorporating coverage ratio, path length, collision penalty, and load balancing. With the discrete path manipulation operators (PMOs) and dynamic learning factors, the proposed method achieves distributed trajectory planning in convex polygonal spaces. Simulation results demonstrate that compared with counterparts, the proposed method performs closer boundaries to actual ones. Furthermore, it achieves 100% coverage while shorten the mission time significantly, validating its adaptability in various convex polygonal scenarios.
Zhou, Yunbo, Zhang, Di, Xia, Wei
Investigating the load-bearing capacity of Titanium Matrix Composites (TMCs) open-hole panels and their mechanically connected components is of great significance for the application of titanium matrix composites in the aerospace field. This paper investigates the failure behavior of TMC open-hole panels with a [45°/45°/-45°/-45°] laminate configuration under tensile loading. Tensile tests were conducted in conjunction with finite element modeling to analyze the damage evolution process and identify the failure modes of the tensile samples. The results show that the simulation outcomes exhibit good consistency with the experimental results, providing a foundation for the structural optimization and theoretical study of TMC open-hole panels.
Gao, Ximan, Jia, Qiuyue, Liu, Shanshan, Meng, Fanling
In recent years, the sales volume of new energy vehicles (NEVs) in China has maintained a steady growth trend, and consumers have paid increasing attention to vehicle range. Against this backdrop, the demand for lightweighting of various core components of NEVs has significantly increased. As a key component of automobiles, the wheel hub accounts for a relatively large proportion of the unsprung mass, and its lightweighting is of great significance for improving the driving range and enhancing vehicle performance. In this paper, sunflower and bridge truss are integrated as design elements, and a small-sized new energy sports utility vehicle (SUV) is selected as the reference vehicle model to design a lightweight wheel hub. Creo is used for 3D modeling of the wheel hub, and static stress, radial fatigue, bending fatigue, and modal simulations are performed in ANSYS Workbench. The results show that all wheel hub performance indicators meet the service requirements. Meanwhile, the quality evaluation indicates that the weight of the designed wheel hub is 10.95 kg, which is 3.90 kg lighter than the original wheel hub, representing a weight reduction of 26.3% compared with the original one, thus meeting the lightweighting standards.
Li, Chang
Because of the imprecision of length quantification in the manufacturing of flat wire windings for flat wire motors, empirical allowances have long been a common practice in production, which in turn leads to considerable material waste and elevated production costs. This paper presents an integrated solution that fuses material experiments, reverse engineering, simulation iteration and parametric design, realizing accurate prediction and quantitative calculation of winding forming length. First, high-precision elastic-plastic constitutive relationships of flat wires are acquired through room-temperature uniaxial tensile tests. On this basis, reverse engineering is applied to derive the initial geometric characteristics and process motion paths of flat wire windings from the 3D model of finished products. Next, an innovative closed-loop iterative compensation algorithm is constructed, with the forming height of the innermost flat wire layer serving as an absolute reference; finite element simulation is then utilized to dynamically optimize the forming length of each flat wire layer. Finally, a parametric design system with a visual interactive interface is developed, which enables an intelligent workflow where precise cutting lengths and equipment motion curves are automatically generated upon input of key design parameters. Production validation results show that this method drastically reduces the length allowances of flat wires, markedly lowers the production scrap rate, and shortens the process debugging cycle of new motor models by more than 80%.
Li, Wenbin, Zhu, Ye
To overcome the trade-off between airflow rate and efficiency in a multi-blade centrifugal fan for automotive air-conditioning systems, as well as the low optimization efficiency of conventional simulation- or experiment-based approaches resulting from the large number of impeller design parameters, a surrogate-model-based optimization framework coupled with an intelligent optimization algorithm is proposed for impeller design. Latin hypercube sampling was employed to generate 120 samples within the design space, and an XGBoost model was integrated with a Bayesian optimization strategy to perform the optimization process. Validation results indicate that the prediction error of the surrogate model is less than 3%. Under the final optimized impeller configuration, the airflow rate is increased by 22% at the design operating condition, while the total pressure efficiency is improved by approximately 20%, satisfying the prescribed design requirements.
Yan, Yaqin, Yue, Chen
While Unmanned Aerial Vehicles (UAVs) hold immense potential for transforming the low-altitude economy, developing an agent that combines both intelligence and flexibility remains a significant challenge. To this end, we propose a novel aerial navigation system, Aeroseek, to search for executable paths that coherently transition from cognitive understanding to physical movement, enabling more autonomous and flexible navigation with instruction guidance. Specifically, given a navigation instruction, we follow a fast-andslow thinking procedure inspired by human pilots by breaking down complex decisions into manageable sub-tasks and initiating motion planning immediately upon the completion of each sub-task for realtime movement. By integrating a multi-branch Chain-of-Thought, Aeroseek is capable of combining reasoning with spatial recognition and self-verification to search for robust sub-goals under expected constraints. For sub-goal navigation, we introduce Online Kinodynamic Monte-Carlo Path Planning (OnKi-MCPP), a novel motion planning approach handling both kinodynamic constraints and path search, while ensuring obstacle avoidance for UAVs. Benefiting from the proposed two-tier searching protocol, Aeroseek demonstrates comprehensive capabilities in processing complicated instructions and adapts to dynamic aerial conditions. Extensive experiments demonstrate the advantages of Aeroseek across tasks of varying complexity.
Luo, Guoan, Xu, Tian, Zhou, Jiacong, Wang, Xianyun
In the production of polyester fibers from recycled polyethylene terephthalate (rPET), the drying and crystallization of plastic bottle flakes are crucial for ensuring the consistency and strength of the finished fibers. Traditionally, rPET production lines still rely on vacuum drum dryers, which have been suffering from issues including agglomeration, uneven heating, and high energy demand. In this work, we developed a novel continuous system that is capable of achieving a total throughput of 1300 kilograms per hour. The design consists of a pulsating fluidized-bed crystallizer and two cylindrical drying towers operating in parallel. Structural performance of the main systems was analyzed using finite element analysis under material load, thermal expansion, and internal air pressure. Airflow behavior and temperature distribution inside the units were studied using Computational Fluid Dynamics (CFD) models, where the flake bed was treated as a porous medium based on experimental bulk density and pressure drop. Results showed that the drying tower maintained a minimum safety factor above 3 under full-load conditions, while the crystallizer also remained well within allowable stress limits. Additionally, flow-field analysis results indicated stable countercurrent airflow, adequate mixing near the inlet region, as well as acceptable axial temperature gradients for moisture removal below 50 ppm. Compared with conventional drum drying, we believe the continuous configuration simplifies operation and reduces heat loss. Our design approach has been combined with analytical calculations on structural and flow simulation, and can be beneficial when applied to similar rPET drying applications.
Wu, Ye, Wu, Tianqi, Ge, Yuchen, Ni, Hongjun, Tan, Linwei, Lv, Shuaishuai
In the process of design and verification of the aircraft ice protection system, a prediction model of ice protection system performance based on Severity Index(IPSI) is proposed, which quantifies the relationship between input and output energy of the ice protection system. In this research, a theoretical calculation method is developed, and the water total collection coefficient and convective heat transfer coefficient on the skin surface were obtained using CFD calculations and rapid neural network prediction methods. The consistency between IPSI and ice protection system performance is verified through an aircraft wing ice protection wind tunnel test. The results show that the lower the slat skin temperature in the ice protection area, the higher the IPSI value, which means the more severe the ice protection system performance. The ice protection performance severity analysis method is carried out for the cases in the CCAR/FAR/CS-25 continuous maximum(CM) envelope of an aircraft, and the IPSI values of each case at some altitudes are calculated, as well as the distribution of the ice protection system performance severity cases in the CM altitude-temperature envelope. The ice protection system performance severity cases are not the highest or lowest atmospheric static temperature in the CM envelope, in which atmospheric static temperature ranges from -8°C to -23°C from low altitude (1500 ft) to high altitude (22000 ft). When the flight speed is constant, and the atmospheric static temperature is gradually reduced, the IPSI value decreases. When the atmospheric static temperature is constant, and the flight speed increases gradually, the IPSI value increases. The influence of water evaporation heat transfer on ice protection performance severity is greater than that of convection heat transfer. The total air temperature for the most severe condition is always 0°C at every altitude. The IPSI calculation model can be used to quickly predict the severity of ice protection system performance in other ice protection areas of aircraft, even wind blades.
Hu, Weixue
Traditional warehousing suffers from low efficiency, high manual error rates, substantial labor costs, and complex deployment, while existing sorting devices remain poorly adaptable for small- and medium-sized operations. To address these issues, this paper presents an intelligent gantry-type grasping device for logistics warehousing based on the MaixCam. The device integrates mechanical design, computer vision, and electronic control. An Arduino Mega2560 serves as the main control board, with 57-series and 42-series stepper motors and servo motors driving the gantry and gripper. The mechanical structure adopts a miniaturized gantry architecture constructed from alloy steel, enabling operation in confined workspaces. A YOLOv5s model with transfer learning was trained for cargo box recognition using a dataset of 654 images collected under various lighting conditions and backgrounds. The model achieves a recognition accuracy of 93%–96% with inference times of 10–14 ms at 25–28 FPS. The proposed device provides a viable solution for automated sorting in small-to medium-sized warehouses, balancing recognition performance, power consumption, and cost.
Xiang, Chang’an, Zhou, Dan, Fan, Zhiwei
To realize automated grasping of randomly placed C-type circlips in automotive and mechanical assembly processes, this paper proposes an identification method based on the improved YOLOv11 algorithm and an exclusive association strategy. First, a detail enhancement convolution (DEConv) module is introduced into the C3k2 module of the YOLOv11 network to enhance the ability to capture the edges and high-frequency details of the circlips; Second, the parallel patch-aware attention (PPA) module is adopted in the detection head instead of the traditional convolution, and through multi-branch fusion and channel-spatial attention mechanism, it adaptively focuses on the key areas of small targets; Finally, the normalized Wasserstein distance (NWD) loss function is used instead of the IoU loss to alleviate the gradient disappearance problem in the positioning of small targets and improve the model’s detection accuracy. Based on precise detection, this paper innovatively proposes a circlip-hole association strategy based on multi-level spatial constraints, achieving accurate pairing of randomly placed circlips through bounding box-inclusive attribution judgment, distance screening, and selection of the best circlip-pair. Experimental results show that compared with the original YOLOv11 model, our model improves the mAP50 and mAP50-95 significantly by 5.7% and 3.3%, respectively; its association accuracy reaches above 95%, and the average processing time is 142 ms. Both in terms of accuracy and speed, our model meets the requirements of industrial real-time grasping and provides reliable prior information for the subsequent precise clamping of the robotic arm.
Wang, Chuang, Li, Jiyan, Wang, Yongming, Tan, Libin
The curvic coupling configuration serves as a foundational element for the joining and torque transmission of aero-engine rotors. The uneven contact stress distribution at its fitting surface can cause tooth surface wear and failure, which in turn leads to the vibration of the entire engine. The curvic couplings are fixed by the pretightening force. The pretightening force greatly influences the contact stress distribution characteristics at the fitting surface. The influence of the pretightening sequence and times on the contact stress distribution characteristics under pretightening force is analyzed in this paper. To reduce the non-uniformity of the contact stress profile, a pretightening force correction model under different pretightening conditions was established. The impacts of the pretightening forces before and after correction on the homogeneity of the contact stress profile were compared. The results show that multi-time pretightening and an appropriate pretightening sequence improve the contact stress profile characteristics. Applying the corrected pretightening force significantly reduces the non-uniformity of the contact stress profile. Specifically, applying the corrected pretightening force multiple times in sequence is effective in further reducing the dispersion of contact stress distribution at the fitting surface. Pretightening in a diagonal sequence is more efficient in improving the homogeneity of contact stress. The research will contribute to precision manufacturing as well as the regulation of aero-engine rotor systems.
Liu, Enxiao, Zhang, Meng, Dong, Jiaxu, Li, Zhibin, Tong, Jinyu, Zheng, Jinde, Liu, Yongmeng
To address the poor cushioning performance of traditional rail car systems, this study proposes a track rail car equipped with a two-stage buffer system. Based on the dynamic principles of the two-stage buffer system, SolidWorks was used to model both the rail car body and its buffer components. The force distribution on the rail car under identical impact loads served as the evaluation metric for cushioning performance. Through theoretical calculations, the optimal spring stiffness configuration that minimized car body stress was identified. Motion simulation software was employed to conduct dynamic analysis and modeling of these configurations. Following this, 3D printing and assembly were performed, with experimental testing conducted on the assembled rail car to compare the effects of different spring types and damping mechanisms on cushioning performance. Performance parameters were optimized accordingly. Results demonstrated that, based on the optimal stiffness combination of the secondary buffering system, a friction damper could be added to further optimize buffer performance.
Zhang, Chi, Yao, Hai