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A large-deflection deformation reconstruction method for semi-flexible plate nozzle based on strain-moment relationship 基于应变矩关系的半柔性板喷管大挠度变形重建方法
Q3 Engineering Pub Date : 2022-12-01 DOI: 10.1051/jnwpu/20224061312
C. Yu, Zhili Zhang, Xuqing Nie, Long Zhang
To enhance the health detection capability of the semi-flexible plate nozzle in a supersonic wind tunnel, a large-deflection deformation reconstruction algorithm for a semi-flexible plate nozzle based on the strain-moment relationship is developed. The multi-jack semi-flexible plate nozzle in the supersonic wind tunnel is studied; its mechanical model of contour assembly is established. The differential equation of flexible plate contour curve is deduced, and the elliptic integral expression of the flexible plate deformation is given. Based on the deformation theory of a rectangular thin plate, the deformation reconstruction algorithm is modified, and its correction effect is simulated and analysed with the finite element method. The maximum deviation after correction is only 10.78% compared with that before correction. The 0.3 m semi-flexible plate nozzle is used as the experimental platform to carry out the experimental study. The experimental results show that under the 6 Mach number, the large-deflection deformation reconstruction results based on strain-moment relationship are in good agreement with the experimental results. The coordinate deviation of the nozzle throat position is about 6.12% compared with the structural deformation, thus verifying that the deformation reconstruction algorithm in this paper is effective and accurate.
为了提高半柔性板喷管在超音速风洞中的健康检测能力,提出了一种基于应变-矩关系的半柔性板喷管大挠度变形重建算法。研究了超声速风洞中多孔半柔性板型喷管;建立了其轮廓装配的力学模型。推导了柔性板轮廓曲线的微分方程,给出了柔性板变形的椭圆积分表达式。基于矩形薄板的变形理论,对变形重建算法进行了改进,并用有限元法对其修正效果进行了仿真分析。校正后的最大偏差仅为校正前的10.78%。采用0.3 m半柔性板型喷嘴作为实验平台进行实验研究。实验结果表明,在6马赫数下,基于应变-矩关系的大挠度变形重建结果与实验结果吻合较好。与结构变形相比,喷管喉部位置的坐标偏差约为6.12%,从而验证了本文的变形重建算法的有效性和准确性。
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引用次数: 0
Fault detection method of secondary sound source in ANC system based on impedance characteristics 基于阻抗特性的ANC系统二次声源故障检测方法
Q3 Engineering Pub Date : 2022-12-01 DOI: 10.1051/jnwpu/20224061242
Haijian Dai, Kean Chen, Yang WANG, Haoxin Yu
As an indispensable component in an active noise control system, the working states of the secondary sound sources affect directly noise reduction and the robustness of the system. Therefore, it is very crucial to detect the working states of the secondary sound sources in the process of active control in real time. In this study, a real-time fault detection method for secondary sound sources during the process of active control is presented, and the corresponding detection algorithm is numerically given and experimentally verified. By collecting the input voltage and output current of the speaker unit, the sound quality factor is calculated to comprehensively judge the working state of the secondary sound sources. The simulation and experimental results show that the present method is simple and has low computational cost, can accurately reflect accurately the working states of the secondary sound sources in real time, and provides a basis for judging the operation of the active noise control system.
二次声源作为有源噪声控制系统中不可或缺的组成部分,其工作状态直接影响系统的降噪效果和鲁棒性。因此,在主动控制过程中,实时检测二次声源的工作状态至关重要。本文提出了一种主动控制过程中二次声源的实时故障检测方法,并对相应的检测算法进行了数值计算和实验验证。通过采集扬声器单元的输入电压和输出电流,计算出音质因子,综合判断二次声源的工作状态。仿真和实验结果表明,该方法简单、计算成本低,能够实时准确地反映二次声源的工作状态,为判断有源噪声控制系统的运行提供了依据。
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引用次数: 1
WSN latency optimization based on path calculation method 基于路径计算方法的WSN时延优化
Q3 Engineering Pub Date : 2022-12-01 DOI: 10.1051/jnwpu/20224061394
P. Zhu, J. Ren, Zhiyuan Ren
随着物联网(IoT)行业的快速发展, 无线传感器网络(WSN)融合云计算技术面临着任务处理时延高、传感器节点能量有限的挑战。因此, 提出了一种基于云雾网络架构的路径计算方法, 利用雾计算层的网络边缘设备计算资源, 将WSN监测任务合理地部署到指定边缘设备上完成处理, 以减少能耗制约下的任务处理时延。为了将任务有效地分配到雾计算层, 采用了一种任务映射规则, 将有向无环图表示的监测任务映射到无向图表示的雾计算层网络; 结合时延和能耗约束建立了一个关于寻求最优映射关系的二值优化问题; 采用模拟退火-离散二值粒子群优化(SA-BPSO)算法实现了对该优化问题的求解。仿真结果显示, 在数据量为10 Mb时, 该方法的时延性能相比较WSN融合云计算技术提高了约40%。
随着物联网(IoT)行业的快速发展, 无线传感器网络(WSN)融合云计算技术面临着任务处理时延高、传感器节点能量有限的挑战。因此, 提出了一种基于云雾网络架构的路径计算方法, 利用雾计算层的网络边缘设备计算资源, 将WSN监测任务合理地部署到指定边缘设备上完成处理, 以减少能耗制约下的任务处理时延。为了将任务有效地分配到雾计算层, 采用了一种任务映射规则, 将有向无环图表示的监测任务映射到无向图表示的雾计算层网络; 结合时延和能耗约束建立了一个关于寻求最优映射关系的二值优化问题; 采用模拟退火-离散二值粒子群优化(SA-BPSO)算法实现了对该优化问题的求解。仿真结果显示, 在数据量为10 Mb时, 该方法的时延性能相比较WSN融合云计算技术提高了约40%。
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引用次数: 1
Lateral attitude control of solar-powered UAV with high aspect ratio 高纵横比太阳能无人机横向姿态控制
Q3 Engineering Pub Date : 2022-12-01 DOI: 10.1051/jnwpu/20224061223
Bo Wang, Heng-wei Zhang, Z. Gao
A solar-powered UAV usually has a high-aspect-ratio and flexible structural design. Its aerodynamic and mass characteristics are different from those of a conventional aircraft. This paper compares the differences in lateral aerodynamic data with those of Class I and Class III aircrafts. Based on the rigid-body dynamics theory, the effects of flexible wing deformation on the stability of the UAV are analyzed. Then, by combining the structural deformation, inertia variation and aerodynamic derivative, the solar-powered UAV's lateral stability is analyzed based on the root locus method. The variation of eigenvalues with wing deformation is also investigated. The rolling moment equation is combined with the kinematic equation to reveal the roll attitude limitation envelope constrained by the kinematic coupling and aileron effects. Taking into account the aerodynamic characteristics of the solar-powered UAV, its wing deformation and roll attitude limitation problem, this paper proposes an adaptive back-stepping control method with strong robustness to achieve the accurate control of the roll attitude of the solar-powered UAV.
太阳能无人机通常具有高展弦比和灵活的结构设计。它的空气动力学和质量特性不同于传统飞机。本文比较了一类和三类飞机在侧向空气动力学数据方面的差异。基于刚体动力学理论,分析了柔性机翼变形对无人机稳定性的影响。然后,结合结构变形、惯性变化和气动导数,基于根轨迹法对太阳能无人机的横向稳定性进行了分析。还研究了特征值随机翼变形的变化。将滚转力矩方程与运动学方程相结合,揭示了受运动学耦合和副翼效应约束的滚转姿态限制包络。考虑到太阳能无人机的气动特性、机翼变形和滚转姿态限制问题,本文提出了一种具有较强鲁棒性的自适应后退控制方法,以实现对太阳能无人机滚转姿态的精确控制。
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引用次数: 2
Research on transition corridor boundary of distributed propulsion VTOL fixed wing 分布式推进垂直起降固定翼过渡通道边界研究
Q3 Engineering Pub Date : 2022-12-01 DOI: 10.1051/jnwpu/20224061195
Yuxuan Cheng, Zhou Zhou, Kelei Wang
The transition state is the most critical and dangerous state of the VTOL fixed wing aircraft in the whole flight process. In this paper, a transition corridor for a distributed propulsion VTOL fixed-wing aircraft is studied based on the lift characteristics of the wing and the power constraints of the power unit. Firstly, according to the sliding flow theory, the dynamic characteristics models of the lift fan system in the front part of the fuselage and the distributed duct system in the rear part of the fuselage were established by introducing the influence factor of the duct, and verified with the test data. Secondly, according to the lift characteristics of the wing, the transition curves of the aircraft at different angles of attack are calculated, in which the transition curves corresponding to the zero-lift attack angle and stall attack angle constitute the lift characteristics transition corridor of the distributed propulsion VTOL fixed-wing aircraft. Finally based on the dynamic performance of the power unit model, calculate the lift characteristic transition each state point in corridor corresponding power demand, according to the power limit of the lift fan system, distributed duct system and power unit total power limitation, get distributed to promote vertical take-off and landing a fixed wing aircraft power limitation in lifting features and power unit under the condition of complete transition corridor. The final results show that the minimum forward velocity is inversely proportional to the attack angle. The power required by the tail distributed duct system will exceed the limit when the aircraft is in low speed and small dip angle transition. For the power limit boundary required, the power limit condition of individual component is stricter than the total power limit condition. The research results of this paper can provide some reference for the transition corridor research of such VTOL fixed-wing aircraft, and on this basis, the subsequent work such as parameter sensitivity analysis and control system design of transition corridor can be carried out.
过渡状态是垂直起降固定翼飞机在整个飞行过程中最关键、最危险的状态。基于机翼的升力特性和动力装置的功率约束,研究了分布式推进垂直起降固定翼飞机的过渡通道。首先,根据滑流理论,引入风管的影响因素,建立了机身前部升力风扇系统和机身后部分布式风管系统的动力学特性模型,并与试验数据进行了验证。其次,根据机翼的升力特性,计算了飞机在不同迎角下的过渡曲线,其中零升力迎角和失速迎角对应的过渡曲线构成了分布式推进垂直起降固定翼飞机的升力特性过渡走廊。最后,基于动力单元模型的动态性能,根据提升风机系统、分布式风管系统和动力单元总功率限制的功率限制,计算出走廊中各状态点对应功率需求的提升特性转换,在完全过渡走廊条件下,固定翼飞机在升力特性和动力单元上的功率限制。最后的结果表明,最小前进速度与攻角成反比。当飞机处于低速小倾角过渡时,机尾分布式风管系统所需的功率将超过极限。对于所需的功率限制边界,单个组件的功率限制条件比总功率限制条件更严格。本文的研究成果可为此类垂直起降固定翼飞机的过渡通道研究提供一些参考,并在此基础上开展过渡通道参数灵敏度分析和控制系统设计等后续工作。
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引用次数: 0
Infrared and visible image fusion algorithm based on split-attention residual networks 基于分散注意残差网络的红外与可见光图像融合算法
Q3 Engineering Pub Date : 2022-12-01 DOI: 10.1051/jnwpu/20224061404
Kun Qian, T. Li, Zhe Li, Meishan Chen
在红外和可见光图像融合算法中, 图像信息的丢失始终是制约融合图像质量提升的关键问题, 为此, 提出了一种基于拆分注意力残差网络的红外和可见光图像融合算法, 使用带有拆分注意力模块的深层残差网络拓展感受野和提高跨通道信息融合能力, 运用平滑最大值单元函数作为激活函数进一步提升网络性能; 特征提取后运用零相位分量分析和归一化算法得到融合权重后完成图像融合。实验结果表明, 融合后的图像细节丰富, 边缘锐利; 在峰值信噪比、结构相似性指数度量和基于梯度的融合性能等指标上与经典的6种算法相比均有不同程度提升。
In infrared and visible light image fusion algorithms, the loss of image information is always a key issue that restricts the improvement of fusion image quality. Therefore, a infrared and visible light image fusion algorithm based on split attention residual network is proposed, which uses a deep residual network with split attention module to expand receptive field and improve cross channel information fusion ability, Using smooth maximum unit functions as activation functions to further improve network performance; After feature extraction, zero phase component analysis and normalization algorithm are used to obtain fusion weights and complete image fusion. The experimental results show that the fused image has rich details and sharp edges; Compared with the classic six algorithms, it has improved to varying degrees in indicators such as peak signal-to-noise ratio, structural similarity index measurement, and gradient based fusion performance.
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引用次数: 0
A dense obstacle avoidance algorithm for UAVs based on safe flight corridor 基于安全飞行走廊的无人机密集避障算法
Q3 Engineering Pub Date : 2022-12-01 DOI: 10.1051/jnwpu/20224061288
L. Fan, Haozhe Zhang, Zhao Xu, Mingwei Lyu, Jin-wen Hu, Chunhui Zhao, Xiaobin Liu
Aiming at the problem of autonomous obstacle avoidance of fixed-wing UAVs in a complex, dense and multi-obstacle environment, a path planning algorithm for fixed-wing UAVs based on a safe flight corridor is proposed. The difficulty of avoiding dense obstacles lies in the choice of obstacle circumvention and traversal: although circumvention is safer, the flight cost is greater; although the traversal cost is lower, the safety threat is higher. How to quickly solve the optimal path is the core issue. This paper firstly defines a safe flight corridor innovatively based on the maneuvering characteristics of fixed-wing UAVs and the Dubins curves. By comprehensively considering UAV flight safety and flight costs, an obstacle threat evaluation function is constructed. Secondly, in view of the computational complexity caused by the dense obstacles, an obstacle clustering algorithm based on obstacle density is proposed, and the nonlinear evaluation function in a high dynamic environment is quickly approximated by Monte Carlo sampling method. Finally, simulations verify the effectiveness of the proposed algorithm in solving dense obstacle avoidance for fixed-wing UAVs.
针对固定翼无人机在复杂、密集、多障碍环境中的自主避障问题,提出了一种基于安全飞行走廊的固定翼无飞行器路径规划算法。避开密集障碍物的困难在于障碍物规避和穿越的选择:尽管规避更安全,但飞行成本更大;尽管遍历成本较低,但安全威胁较高。如何快速求解最优路径是核心问题。本文首先根据固定翼无人机的机动特性和Dubins曲线,创新性地定义了安全飞行走廊。通过综合考虑无人机飞行安全和飞行成本,构建了障碍物威胁评估函数。其次,针对密集障碍物带来的计算复杂性,提出了一种基于障碍物密度的障碍物聚类算法,并采用蒙特卡罗采样方法快速逼近高动态环境下的非线性评价函数。最后,仿真验证了该算法在解决固定翼无人机密集避障问题中的有效性。
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引用次数: 1
Image enhancement method based on exposure fusion for UAV aerial photography 基于曝光融合的无人机航拍图像增强方法
Q3 Engineering Pub Date : 2022-12-01 DOI: 10.1051/jnwpu/20224061327
Liangliang Li, Jian-lin Ren, Peng Wang, Z. Lyu, Mengyu Sun, Xiaoyan Li, Wuqi Gao
针对无人机航拍图像光照不均匀及自然雾导致影像质量退化问题, 提出了一种无人机航拍图像增强算法。利用改进的低照度图像增强算法均衡亮度对比度; 为了解决均衡后图像过增强问题, 提出了联合去雾及曝光融合的色彩矫正增强方法; 为了保留增强图像的边缘纹理信息, 设计了一种效果更佳的细节增强算法, 处理后统计直方图更为平滑, 可在一定程度上抑制部分噪声, 细节纹理信息更强。实验结果表明, 所提的航拍图像增强算法, 能够有效解决因光照不均或自然雾引起的影像退化现象, 提高了无人机航拍图像的质量, 主客观图像质量评价指标优于现有绝大多数主流算法, 性能更佳。
A drone aerial image enhancement algorithm is proposed to address the issue of uneven lighting and degradation of image quality caused by natural fog in drone aerial images. Utilize an improved low illumination image enhancement algorithm to balance brightness contrast; To solve the problem of image over enhancement after equalization, a color correction and enhancement method combining defogging and exposure fusion is proposed; In order to preserve the edge texture information of the enhanced image, a more effective detail enhancement algorithm has been designed. After processing, the statistical histogram is smoother, which can suppress some noise to a certain extent, and the detail texture information is stronger. The experimental results show that the proposed aerial image enhancement algorithm can effectively solve the phenomenon of image degradation caused by uneven lighting or natural fog, improve the quality of unmanned aerial vehicle aerial images, and the subjective and objective image quality evaluation indicators are superior to the majority of existing mainstream algorithms, with better performance.
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引用次数: 0
Improved reduce-order modeling of bidirectional interleaved boost with coupled inductors converter 耦合电感变换器双向交错升压降阶模型的改进
Q3 Engineering Pub Date : 2022-10-01 DOI: 10.1051/jnwpu/20224051046
Yuchen Zhang, Ruiqing Ma, P. Fan
In this paper, an improved reduced-order average modeling method for the bidirectional interleaved boost with coupled inductors (BIBCI) converter is proposed, based on the PWM and phase-shift dual-degree-of-freedom modulation and traditional reduced-order average model. Considering the power loss of the coupled inductor, the core loss, and the parasitic parameters of the inductors, capacitors, and switches in the circuit topology, the new model reflects the dynamic performance of the converter in a wide frequency domain more accurately than the traditional model. The small-signal model and transfer function are further deduced to provide a basis for the design of closed-loop controllers and have good engineering practicability. According to voltage source load or resistive load, the double-loop or triple-loop controller is designed correspondingly. The two models are theoretically analyzed and compared, and the proposed controller is verified by a 1.5 kW prototype.
提出了一种基于PWM和相移双自由度调制和传统降阶平均模型的双向交错升压耦合电感(BIBCI)变换器改进的降阶平均建模方法。考虑耦合电感的功率损耗、铁芯损耗以及电感、电容和开关在电路拓扑中的寄生参数,新模型比传统模型更准确地反映了变换器在宽频域的动态性能。进一步推导了小信号模型和传递函数,为闭环控制器的设计提供了依据,具有较好的工程实用性。根据电压源负载或电阻性负载,设计相应的双环或三环控制器。对两种模型进行了理论分析和比较,并通过1.5 kW样机对所提出的控制器进行了验证。
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引用次数: 1
Relationship of fracture behavior and stress triaxiality of additive manufactured Ti-6Al-4V 增材Ti-6Al-4V断裂行为与应力三轴性的关系
Q3 Engineering Pub Date : 2022-10-01 DOI: 10.1051/jnwpu/20224050962
B. Gao, Wei Huang, Shen Wang, Shuangyin Zhang, Xianmin Chen
It is significant to study the relationship between the stress triaxiality and the fracture behavior for analyzing the failure process of additive manufactured titanium alloy. This paper combined the tensile test of smooth round bar specimens and notched round bar specimens with the numerical simulation to obtain the stress triaxiality distribution and fracture strain in order to study fracture behavior of additive manufactured titanium under different stress triaxiality. Fracture analysis was proceeded by using scanning electronic microscope to analyze the correlation between the stress triaxiality and the fracture behavior. Results show that the fracture strain decreases while the stress triaxiality increases and the location of the crack initiation moves from the center to the edge of the minimum cross-section while the radius of the notch decrease.
研究应力三轴度与断裂行为之间的关系,对分析添加剂制造钛合金的失效过程具有重要意义。本文将光滑圆棒试样和缺口圆棒试样的拉伸试验与数值模拟相结合,获得了应力三轴度分布和断裂应变,以研究添加剂制备的钛在不同应力三轴向度下的断裂行为。利用扫描电子显微镜进行断裂分析,分析应力三轴度与断裂行为之间的相关性。结果表明,随着应力三轴度的增加,断裂应变减小,裂纹萌生位置从最小截面的中心向边缘移动,缺口半径减小。
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引用次数: 0
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西北工业大学学报
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