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Aerodynamic Performance of Three Flapping Wings with Unequal Spacing in Tandem Formation
编辑人员丨6天前
To better understand the aerodynamic reasons for highly organized movements of flying organisms,the three-flapping wing system in tandem formation was studied numerically in this paper.Different from previous relevant studies on the multiple flapping wings that are equally spaced,this study emphasizes the impact of unequal spacing between individuals on the aerodynamics of each individual wing as well as the whole system.It is found that swapping the distance between the first and second wing with the distance between the second wing and the rearmost wing does not affect the overall aerodynamic performance,but significantly changes the distribution of aerodynamic benefits across each wing.During the whole flap-ping cycle,three effects are at play.The narrow channel effect and the downwash effect can promote and weaken the wing lift,respectively,while the wake capture effect can boost the thrust.It also shows that these effects could be manipulated by changing the spacing between adjacent wings.These findings provide a novel way for flow control in tandem formation flight and are also inspiring for designing the formation flight of bionic aircraft.
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编辑人员丨6天前
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Design and Experimental Verification of a Roll Control Strategy for Large Wingspan Flapping-Wing Aerial Vehicle
编辑人员丨6天前
Most flapping-wing aircraft wings use a single degree of freedom to generate lift and thrust by flapping up and down,while relying on the tail control surfaces to manage attitude.However,these aircraft have certain limitations,such as poor accuracy in attitude control and inadequate roll control capabilities.This paper presents a design for an active torsional mechanism at the wing's trailing edge,which enables differential variations in the pitch angle of the left and right wings during flapping.This simple mechanical form significantly enhances the aircraft's roll control capacity.The experimental verification of this mechanism was conducted in a wind tunnel using the RoboEagle flapping-wing aerial vehicle that we developed.The study investigated the effects of the control strategy on lift,thrust,and roll moment during flapping flight.Additionally,the impact of roll control on roll moment was examined under various wind speeds,flapping frequencies,angles of attack,and wing flexibility.Furthermore,several rolling maneuver flight tests were performed to evaluate the agility of RoboEagle,utilizing both the elevon control strategy and the new roll control strategy.The results demonstrated that the new roll control strat-egy effectively enhances the roll control capability,thereby improving the attitude control capabilities of the flapping-wing aircraft in complex wind field environments.This conclusion is supported by a comparison of the control time,maximum roll angle,average roll angular velocity,and other relevant parameters between the two control strategies under identical roll control input.
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编辑人员丨6天前
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Elite Dung Beetle Optimization Algorithm for Multi-UAV Cooperative Search in Mountainous Environments
编辑人员丨6天前
This paper aims to address the problem of multi-UAV cooperative search for multiple targets in a mountainous environment,considering the constraints of UAV dynamics and prior environmental information.Firstly,using the target probability dis-tribution map,two strategies of information fusion and information diffusion are employed to solve the problem of environ-mental information inconsistency caused by different UAVs searching different areas,thereby improving the coordination of UAV groups.Secondly,the task region is decomposed into several high-value sub-regions by using data clustering method.Based on this,a hierarchical search strategy is proposed,which allows precise or rough search in different probability areas by adjusting the altitude of the aircraft,thereby improving the search efficiency.Third,the Elite Dung Beetle Optimization Algorithm(EDBOA)is proposed based on bionics by accurately simulating the social behavior of dung beetles to plan paths that satisfy the UAV dynamics constraints and adapt to the mountainous terrain,where the mountain is considered as an obstacle to be avoided.Finally,the objective function for path optimization is formulated by considering factors such as coverage within the task region,smoothness of the search path,and path length.The effectiveness and superiority of the proposed schemes are verified by the simulation.
Mountainous environment Multi-UAV cooperative search Environment information consistency Elite dung beetle optimization algorithm(EDBOA)...不再出现此类内容
编辑人员丨6天前
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试飞员选拔年龄和飞行时间及人格特征调查
编辑人员丨6天前
目的:探讨试飞员选拔的年龄和飞行时间及人格特征,为制订试飞员选拔技术规范提供理论基础。方法:随机抽取36名试飞大队试飞员,从中选取飞行时间≥2 500 h的30名试飞员进行访谈,对访谈资料编码整理,形成试飞员选拔的年龄及飞行时间。36名试飞员完成卡特尔16人格因素测验(Cattell's 16 Personality Factor,16PF)和明尼苏达多相人格测验(Minnesota Multiphasic Personality Inventory,MMPI)评估,按照年龄分为30~39岁组和40~49岁组,比较不同年龄组试飞员16PF和MMPI得分。结果:歼击机试飞员选拔年龄适用条件为30~35岁,飞行时间为1 000 h以上;轰炸机及运输机试飞员选拔年龄适用条件为30~35岁,无飞行时间限制;两类试飞员选拔均应符合高性能战斗机飞行员体格要求。MMPI得分中,30~39岁组试飞员的校正量表得分显著高于40~49岁组( U=97.50, P=0.040),精神分裂量表得分则显著低于40~49岁组( U=95.50, P=0.035),其他人格特征量表得分组间差异均无统计学意义( P值均>0.05)。 结论:不同机种试飞员选拔对飞行时间的要求不同。不同年龄段试飞员人格特征差异不显著,但仍需进一步研究试飞员选拔的年龄标准。
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编辑人员丨6天前
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军事飞行人员脑海绵状血管畸形10例及航空医学鉴定
编辑人员丨6天前
目的:探讨军事飞行人员脑海绵状血管畸形(cerebral cavernous malformations,CCM)的诊疗及航空医学鉴定。方法:收集空军特色医学中心2015—2021年收治的诊断为CCM的飞行人员临床资料及航空医学鉴定结论,结合国内外相关鉴定案例及文献进行分析。结果:共收集10例飞行人员病例,均为男性,年龄20~41岁,平均年龄28.3岁。其中飞行员8例,空中战技勤人员2例。飞行时间110~4 000 h,平均飞行时间1 102.0 h。病灶大小3~12 mm,其中<5 mm 2例,5~10 mm 6例,>10 mm 2例。病灶位置包括枕叶(1例)、额叶(4例)、颞叶(2例)、小脑半球(3例),均位于皮层下。10例飞行人员中,仅有1例首发症状为颅内出血(右侧小脑半球),予以手术治疗。3例飞行人员处于地面观察期,航空医学鉴定结论为暂时飞行不合格。其余7例飞行人员随访时间均超过6个月,复查MRI示病变均无改变、脑电图无异常,其中2例空中战技勤人员航空医学鉴定结论为飞行合格;1例直升机飞行员鉴定结论为飞行合格(限副驾驶),2例双座歼击机飞行员鉴定结论分别为飞行合格(限双座机)、飞行合格,2例单座歼击机飞行员鉴定结论为更改原机种后飞行合格(限轰炸机、运输机和直升机)。结论:对于CCM军事飞行人员应根据有无症状、病变部位和大小、失能可能性评估、治疗效果、地面观察随访结果以及飞行机种和职别做出航空医学鉴定结论。
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编辑人员丨6天前
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军事飞行人员颅内动脉瘤医学鉴定的探讨——附三例临床病例
编辑人员丨6天前
目的:探讨军事飞行人员颅内动脉瘤的航空医学鉴定原则。方法:分析空军特色医学中心影像学检查中检出的2例颅内动脉瘤歼击机飞行员,以及1例颅内动脉瘤致蛛网膜下腔出血的运输机通信员的临床诊治过程及最终医学鉴定结论,并进行相关文献复习。结果:2例歼击机飞行员均无临床症状、体征,于体检过程中行头颅磁共振血管成像检查意外检出直径小于<5 mm的微小动脉瘤。其中1例经数字减影血管造影确诊为颅微小动脉瘤,经双座飞行观察1年后最终建议降机种飞行;另1例经进一步影像学检查及专家阅片会诊,排除动脉瘤诊断,给予飞行合格、定期影像学随访结论。1例运输机通信员因蛛网膜下腔出血住院,经数字减影血管造影检查确诊为颅内小动脉瘤,行夹闭术后经13个月地面随访观察,无新发症状及体征,给予特许飞行合格。结论:航空环境的特殊性可能对动脉瘤的发生、发展有一定影响。歼击机飞行员颅内微小动脉瘤未治疗者飞行不合格。运输机等低载荷飞机飞行人员颅内微小动脉瘤未治疗者应结合飞行任务逐例进行分析,可能给予特许飞行;颅内动脉瘤经治疗后,无临床后遗症,可考虑给予特许飞行。
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编辑人员丨6天前
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飞行人员心脏瓣膜病临床诊治与特许飞行医学鉴定
编辑人员丨6天前
目的:分析飞行人员心脏瓣膜病发病特点、治疗方法,为规范心脏瓣膜病的术后航空医学鉴定提供参考依据。方法:收集2010年11月至2021年12月在空军特色医学中心(原空军总医院)住院治疗的患心脏瓣膜病的飞行人员病例资料,称为临床组;检索文献报道的国内飞行人员瓣膜病相关病例,称为文献组。根据飞行机种、病变部位、治疗方法、鉴定结果进行回顾性分析。结果:临床组20例,按检出例数从多到少其瓣膜位置依次为主动脉瓣(12例)、二尖瓣(7例)、三尖瓣(4例,均为伴发)、肺动脉瓣(1例);文献组11例,以主动脉瓣病变为主(10例),三尖瓣病变1例。其中主动脉瓣病变大部分以主动脉瓣二瓣化畸形(bicuspid aortic valve,BAV)为病理基础。主动脉瓣病变的病例中12例飞行合格,1例限定飞行,1例由歼击机改飞运输机,3例暂时飞行不合格,3例飞行不合格,2例特许飞行。二尖瓣病变病例中3例飞行合格,4例暂时飞行不合格。1例三尖瓣病变病例和1例肺动脉瓣病变病例均飞行合格。结论:病变累及瓣膜部位是影响航空医学鉴定的主要因素,飞行人员瓣膜病发病部位最多见的是主动脉瓣,其中BAV为最常见病理类型,需加强体检鉴定和防治。
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编辑人员丨6天前
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某型军用运输机机组氧气系统供氧防护性能的低压舱生理试验评价
编辑人员丨6天前
目的:评价某型军用运输机机组氧气系统供氧防护性能,为产品设计定型提供生理试验依据。方法:4具假人和4名健康志愿者配戴个体防护装备,使用某型军用运输机机组氧气系统,先后在低压舱内完成4项试验,包括氧气系统供氧性能物理试验、氧气系统迅速减压物理试验、6 h巡航高度供氧生理试验和12.0 km高空迅速减压生理试验。测试面罩内的氧气浓度、呼吸阻力、安全余压、迅速减压峰值面罩压、作用时间和稳压值等物理参数;监测志愿者心电图和血氧饱和度等生理参数。结果:假人肺通气量为20 L/min时,该型军用运输机机组氧气系统在12.0 km以下提供的供氧分压≥19.1 kPa,安全余压接通前系统呼气阻力≤441.3 Pa,吸气阻力≤490.3 Pa。假人肺容积为1.0 L时,系统的迅速减压峰值≤5.8 kPa。6 h巡航飞行时,氧气系统为志愿者提供的供氧氧分压均≥21.9 kPa。4名志愿者均完成12.0 km高空迅速减压生理试验,主客观反应良好。结论:该型军用运输机机组氧气系统防护性能可以满足地面至12.0 km高度供氧防护要求。
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编辑人员丨6天前
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高性能战斗机飞行员高原驻训后急性缺氧耐力情况调查
编辑人员丨6天前
目的:探讨高原驻训对飞行员急性缺氧耐力的影响,为航空卫生保障提供依据。方法:对18名参加高原驻训3个月,初下高原1周的高性能战斗机飞行员(驻训组)和36名未参加驻训的同机种飞行员(对照组)进行抗荷抗缺氧训练。以缺氧体验训练合格线2 min为界,每20 s记录1次飞行员的动脉血氧饱和度(arterial oxygen saturation,SaO 2)和心率。运用飞行员抗荷抗缺氧能力检测仪、BeneView T6型心电监护仪进行训练、评估和监测。 结果:随着缺氧时间的延长,从缺氧体验训练60 s开始,在相应的时间节点上,驻训组飞行员SaO 2均显著高于对照组,差异有统计学意义( t=2.63、3.32、4.79、4.32, P=0.011、0.002、<0.001、<0.001)。对照组飞行员的平均SaO 2随缺氧时间延长下降迅速,而驻训组随缺氧时间延长下降缓慢;驻训组飞行员的平均有效意识时间为(441.11±67.03)s,显著长于对照组的(195.00±31.49)s,是对照组的2.26倍,差异有统计学意义( t=17.74, P<0.001)。 结论:高原驻训后高性能战斗机飞行员急性缺氧状态下的SaO 2和有效意识时间得到显著提高。短期的慢性缺氧过程能显著提高飞行员的急性缺氧耐力,以利于有效应对高空缺氧。
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编辑人员丨6天前
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航母舰员眼科疾病谱分析与对策
编辑人员丨6天前
目的:通过调查某航母舰员眼部疾病种类及部门分布,分析致病原因,为进一步制定航母舰员眼科保健计划提供依据。方法:对某航母医疗中心2020年5-7月眼科就诊记录进行分析,统计疾病人数、部门分布、疾病种类等数据。结果:眼科就诊舰员总人数97例,男性74例,女性23例。患病人数前3位的部门为舰务、机电、行政,分别为36例(37.11%)、22例(22.68%)、19例(19.59%)。发病率前3位的疾病为干眼症、结膜炎、睑板腺功能障碍,分别为30例(30.93%)、28例(28.87%)、19例(19.59%)。结论:航母环境下舰员眼科疾病的防治措施包括加强人员眼卫生宣教,改善舱室照明及通风系统,加强高发病部门巡诊和针对性治疗。
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编辑人员丨6天前
