The external rotor hub motor adopts direct drive mode,no deceleration drive device,and has a compact *** axial size is smaller than that of a deceleration-driven hub motor,which greatly reduces the weight of the vehic...
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The external rotor hub motor adopts direct drive mode,no deceleration drive device,and has a compact *** axial size is smaller than that of a deceleration-driven hub motor,which greatly reduces the weight of the vehicle and increases the cruising range of the *** of the limited special working environment and performance requirements,the hub motor has a small internal space and a large heat generation,so it puts forward higher requirements for heat dissipation *** the external rotor hub motor,a new type of in-tank watercooled structure of hub motor was proposed to improve its cooling effect and ***,the threedimensional finite element model of the motor is established to analyze the characteristics of motor loss and temperature field ***,the cooling performance of different cooling structures in the tank was ***,the thermal network model and three-dimensional finite element analysis were used to optimize the water-cooled structure in the tank,and the power density of themotor was improved by improving the cooling performance under the condition of volume limitation of the hub *** results show that the cooling effect of the proposed water-cooled structure in the tank is significant under the condition of constant power *** to natural ventilation,the maximum temperature was reduced by 33.13°C and the cooling effect was increased by about 27.7%.
The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram *** dynamic expansion of the cavity induces liquid pressure variations...
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The cavity characteristics in liquid-filled containers caused by high-velocity impacts represent an important area of research in hydrodynamic ram *** dynamic expansion of the cavity induces liquid pressure variations,potentially causing catastrophic damage to the *** studies mainly focus on non-deforming projectiles,such as fragments,with limited exploration of shaped charge *** this paper,a uniquely experimental system was designed to record cavity profiles in behind-armor liquid-filled containers subjected to shaped charge jet *** impact process was then numerically reproduced using the explicit simulation program ANSYS LS-DYNA with the Structured Arbitrary Lagrangian-Eulerian(S-ALE)*** formation mechanism,along with the dimensional and shape evolution of the cavity was ***,the influence of the impact kinetic energy of the jet on the cavity characteristics was *** findings reveal that the cavity profile exhibits a conical shape,primarily driven by direct jet impact and inertial *** expansion rates of both cavity length and maximum radius increase with jet impact kinetic *** the impact kinetic energy is reduced to 28.2 kJ or below,the length-to-diameter ratio of the cavity ultimately stabilizes at approximately 7.
Ammonia-diesel dual fuel(ADDF)engines for transportation applications are an important way to reduce carbon *** order to achieve better combustion of ammonia in diesel engines.A small-bore single-cylinder engine was c...
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Ammonia-diesel dual fuel(ADDF)engines for transportation applications are an important way to reduce carbon *** order to achieve better combustion of ammonia in diesel engines.A small-bore single-cylinder engine was converted into an ADDF engine with the help of mature computational fluid dynamics(CFD)simulation software to investigate the performance of an engine with a high ammonia energy ratio(AER),and to study the effect of spray tilt angle on ADDF *** results showed that the increase in AER reduced nitric oxide(NO)and nitrogen dioxide(NO2)emissions but increased nitrous oxide(N2O)and unburned ammonia *** in the range of 50%-70%achieved lower greenhouse gases(GHG)emissions than the pure diesel *** to the pure diesel mode,when the AER was 60%,the indicated thermal efficiency(ITE)was increased by 0.2%and the GHG emissions were decreased by 22.3%,but carbon monoxide(CO)and Hydrocarbon(HC)emissions were *** the in-cylinder combustion temperature or high-temperature region range of the ADDF engine could reduce GHG *** an AER of 60%,an increase in the spray tilt angle helped the ammonia combustion in the residual gap to reduce the unburned ammonia *** to the pure diesel mode with a spray tilt angle of 75°,an AER of 60%with a spray tilt angle of 77.5°improved the ITE by 1.5%,and reduced theGHGemissions by 25.7%.Adjusting the spray tilt angle of theADDFengine also *** is an effective way to improve ADDF engine performance by adjusting the spray tilt angle.
Background: The condition that vehicles are prone to skidding during emergency lane changing, an anti-rollover constraint is added to the trajectory planning. Methods: The evaluation index is constructed by the latera...
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In order to reduce the labor intensity of high-altitude workers and realize the cleaning and maintenance of high-rise building exteriors,this paper proposes a design for a 4-DOF bipedal wall-climbing bionic robot insp...
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In order to reduce the labor intensity of high-altitude workers and realize the cleaning and maintenance of high-rise building exteriors,this paper proposes a design for a 4-DOF bipedal wall-climbing bionic robot inspired by the inchworm’s *** robot utilizes vacuum adsorption for vertical wall attachment and legged movement for *** enhance the robot’s movement efficiency and reduce wear on the adsorption device,a gait mimicking an inchworm’s movement is planned,and foot trajectory planning is performed using a quintic polynomial *** velocity constraints,foot trajectory optimization is achieved using an improved Particle Swarm Optimization(PSO)algorithm,determining the quintic polynomial function with the best fitness through ***,through comparative experiments,the climbing time of the robot closely matches the simulation results,validating the trajectory planning method’s accuracy.
Brain–computer interface (BCI) systems, such as the P300 speller, enable patients to express intentions withoutnecessitating extensive ***, the complexity of operational instructions and the slow pace of characterspe...
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Brain–computer interface (BCI) systems, such as the P300 speller, enable patients to express intentions withoutnecessitating extensive ***, the complexity of operational instructions and the slow pace of characterspelling pose challenges for some patients. In this paper, an image segmentation P300 selector based on YOLOv7-mask and DeepSORT is proposed. The proposed system utilizes a camera to capture real-world objects forclassification and tracking. By applying predefined stimulation rules and object-specificmasks, the proposed systemtriggers stimuli associated with the objects displayed on the screen, inducing the generation of P300 signals in thepatient’s brain. Its video processing mechanism enables the system to identify the target the patient is focusing oneven if the object is partially obscured, overlapped, moving, or changing in number. The system alters the target’scolor display, thereby conveying the patient’s intentions to caregivers. The data analysis revealed that the selfrecognitionaccuracy of the subjects using this method was between 92% and 100%, and the cross-subject P300recognition precision was 81.9%–92.1%. This means that simple instructions such as “Do not worry, just focuson what you desire” effectively discerned the patient’s intentions using the Image Segmentation-P300 selector. Thisapproach provides cost-effective support and allows patients with communication difficulties to easily express theirneeds.
In this paper, we explore a distributed online convex optimization problem over a time-varying multi-agent network. The network aims to minimize a global loss function through local computation and communication with ...
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In this paper, we explore a distributed online convex optimization problem over a time-varying multi-agent network. The network aims to minimize a global loss function through local computation and communication with neighboring agents. To effectively handle the optimization problem which involves highdimensional and structural constraint sets, we develop a distributed online multiple Frank-Wolfe algorithm that circumvents the expensive computational cost associated with projection operations. The dynamic regret bounds are established as O(T1-γ+ HT) with the linear oracle number O(T1+γ), which depends on the horizon（total iteration number） T, the function variation HT, and the tuning parameter 0 < γ < *** particular, when the prior knowledge of HTand T is available, the bound can be enhanced to O（1 +HT）. Moreover, we explore the significant advantages provided by the multiple iteration technique and reveal a trade-off between dynamic regret bound, computational cost, and communication cost. Finally,the performance of our algorithm is validated and compared through the distributed online ridge regression problems with two constraint sets.
Accurate prediction of the state-of-charge(SOC)of battery energy storage system(BESS)is critical for its safety and lifespan in electric *** overcome the imbalance of existing methods between multi-scale feature fusio...
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Accurate prediction of the state-of-charge(SOC)of battery energy storage system(BESS)is critical for its safety and lifespan in electric *** overcome the imbalance of existing methods between multi-scale feature fusion and global feature extraction,this paper introduces a novel multi-scale fusion(MSF)model based on gated recurrent unit(GRU),which is specifically designed for complex multi-step SOC prediction in practical *** correlation analysis is first employed to identify SOC-related *** parameters are then input into a multi-layer GRU for point-wise feature ***,the parameters undergo patching before entering a dual-stage multi-layer GRU,thus enabling the model to capture nuanced information across varying time ***,by means of adaptive weight fusion and a fully connected network,multi-step SOC predictions are *** extensive validation over multiple days,it is illustrated that the proposed model achieves an absolute error of less than 1.5%in real-time SOC prediction.
Hybrid deposition with microrolling is a promising arc-based direct energy deposition technique to rapidly build complex parts,whose performance is comparable to that of their wrought *** forming conditions and bead m...
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Hybrid deposition with microrolling is a promising arc-based direct energy deposition technique to rapidly build complex parts,whose performance is comparable to that of their wrought *** forming conditions and bead morphologies pose difficulties in controlling the morphologies from a single weld bead to built part profiles,and these difficulties hinder the widespread application of the ***,a model that can automatically generate optimal process parameters on the basis of the infrared image,including thermal information and the point cloud information of the target weld bead,is *** show that the errors in critical parameters,namely,feed speed,travel speed,and rolling force,are below 0.4%,0.9%,and 2%,respectively,indicating that the proposed technique outperforms the compared ***,validation reveals that the actual depositing bead is similar(deviation below 0.05 mm)to the target *** proposed strategy provides an effective foundation for dynamic path planning and can considerably improve printing efficiency and precision.
Understanding the dynamic response of composite material cartridges during the firing process is of great significance for improving their reliability and safety.A theoretical model describing the dynamic response of ...
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Understanding the dynamic response of composite material cartridges during the firing process is of great significance for improving their reliability and safety.A theoretical model describing the dynamic response of composite material cartridges is established based on the thick-walled cylinder theory and rate-dependent constitutive model of composite *** correctness of the theoretical model is validated through finite element simulations of cartridge *** influence of chamber pressure and cartridge wall thickness on the cartridge's deformation process and stress distribution is *** results indicate that the primary deformation of composite material cartridges inside the chamber is elastic *** to metal cartridges,composite material cartridges require higher pressure for touching-chamber and are more prone to developing gaps after unloading to ensure smooth *** the deformation process,the touching-chamber behavior of the cartridge can improve the stress *** the same chamber pressure,the touching-chamber behavior can reduce the circumferential stress by approximately 30%.The inner wall surface of the cartridge is a critical area that requires *** touching-chamber behavior can be facilitated by appropriately reducing the cartridge wall thickness while ensuring overall *** study can provide guidance for the optimization design of composite material cartridges.
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