High-aspect-ratio aircraft are widely used in military and civilian fields,such as reconnaissance,surveillance,and attacks,due to their high lift-to-drag ratio,strong payload capability,significant endurance effect,an...High-aspect-ratio aircraft are widely used in military and civilian fields,such as reconnaissance,surveillance,and attacks,due to their high lift-to-drag ratio,strong payload capability,significant endurance effect,and good stealth performance.However,compared to conventional aircraft,high-aspect-ratio aircraft are more susceptible to gust disturbances during flight.In response to this phenomenon,a full-scale dynamic model of a high-aspect-ratio unmanned aerial vehicle was developed.Considering the coupling among control surfaces,structural forces,and aerodynamic forces,along with sensor,actuator,and delay effects,an H_(∞)control law was designed using the principle of singular value energy flow reduction and weighted function,with a PID(Proportional-Integral-Derivative)control law for comparison.The two controllers were then subjected to pulse-response and jury stability tests.Finally,wind tunnel tests were conducted to investigate the gust alleviation principle,in which gust disturbances were generated using gust generators and control surface self-excitation.The results present that the average wing root bending moment and wing tip overload under the PID control law decrease by approximately 30%,while under the H_(∞)control law,both the average wing root bending moment and wing tip overload reduction rate exceed 50%,with peaks reaching 60%.This validates the feasibility and efficiency of the designed H_(∞)controller.展开更多
A computational and test method for calibrating the flight loads carried by aircraft wings is proposed.The wing load is measured in real-time based on the resistance and fiber Bragg grating strain gauges.The linear st...A computational and test method for calibrating the flight loads carried by aircraft wings is proposed.The wing load is measured in real-time based on the resistance and fiber Bragg grating strain gauges.The linear stepwise regression method is used to construct the load equations.The mean impact value algorithm is employed to select suitable bridges.In the ground calibration experiment,the wing load calculation equations in both forward and reverse installation states are calibrated.The correctness of the load equations was verified through equation error and inspection error analysis.Finally,the actual flight load of the wing was obtained through flight tests.展开更多
In the highly fragmented landscape of central Europe, dispersal is of particular importance as it determines the long-term survival of animal populations. Dispersal not only secures the recolonization of patches where...In the highly fragmented landscape of central Europe, dispersal is of particular importance as it determines the long-term survival of animal populations. Dispersal not only secures the recolonization of patches where populations went extinct, it may also rescue small populations and thus prevent local extinction events. As dispersal involves different individual fitness costs, the decision to disperse should not be random but context- dependent and often will be biased toward a certain group of individuals （e.g., sex- and wing morph-biased dispersal）. Although biased dispersal has far-reaching consequences for animal populations, immediate studies of sex- and wing morph-biased dispersal in orthopterans are very rare. Here, we used a combined approach of morphological and genetic analyses to investigate biased dispersal of Metrioptera bicolor, a wing dimorphic bush-cricket. Our results clearly show wing morph-biased dispersal for both sexes of M. bicolor. In addition, we found sex-biased dispersal for macropterous individuals, but not for micropters. Both, morphological and genetic data, favor macropterous males as dispersal unit of this bush-cricket species. To get an idea of the flight ability ofM. bicolor, we compared our morphological data with that of Locusta migratoria and Schistocerca gregaria, which are very good flyers. Based on our morphological data, we suggest a good flight ability for macropters of M. bicolor, although flying individuals of this species are seldom observed.展开更多
Insect flight is a complex trait involved in different behaviors,from the search for sexual partners,food,or breeding sites.Many studies have postulated the adaptive advantages of certain morphological traits in relat...Insect flight is a complex trait involved in different behaviors,from the search for sexual partners,food,or breeding sites.Many studies have postulated the adaptive advantages of certain morphological traits in relation to increased flight capacity,such as low values of wing loading or high values of wing:thorax ratio and wing-aspect ratio.However,few studies have evaluated the relationship between variables related to flight and morphological traits in Drosophila.This work aimed to study morphological traits in males and females of two pairs of sibling species:Drosophila buzzati Patterson and Wheeler-Drosophila koeferae Fontdevila and Wasserman,and Drosophila melanogaster Meigen-Drosophila simulans Sturtevant,and to analyze its relationship with flight.We detected the highest proportion of flight time in D.koepferae and D.simulans compared to D.buzzati and D.melanogaster,respectively.Our results also revealed sexual dimorphism,with males exhibiting a higher proportion of flight time than females.Surprisingly,we did not find a general pattern to explain the relationship between morphology and the proportion of flight time because associations varied depending upon the analyses(considering all groups together or each sex-species combination separately).Moreover,these associations explained a low percentage of variation,suggesting that other nonmorphological components related to flight,such as physiological variables,should be taken into account.This work allowed us to show the variability and complexity of an aspect of flight,suggesting that the adaptive role of the morphological traits studied might have been overestimated.展开更多
Changes in the environmental conditions experienced by naturally occurring populations are frequently accompanied by changes in adaptive traits allowing the organ- ism to cope with environmental unpredictability. Phen...Changes in the environmental conditions experienced by naturally occurring populations are frequently accompanied by changes in adaptive traits allowing the organ- ism to cope with environmental unpredictability. Phenotypic plasticity is a major aspect of adaptation and it has been involved in population dynamics of interacting species. In this study, phenotypic plasticity （i,e., environmental sensitivity） of morphological adap- tive traits were analyzed in the cactophilic species Drosophila buzzatii and Drosophila koepferae （Diptera： Drosophilidae） considering the effect of crowding conditions （low and high density）, type of competition （intraspecific and interspecific competition） and cacti hosts （Opuntia and Columnar cacti）. All traits （wing length, wing width, thorax length, wing loading and wing aspect） showed significant variation for each environmental factor considered in both Drosophila species. The phenotypic plasticity pattern observed for each trait was different within and between these cactopbilic Drosophila species depending on the environmental factor analyzed suggesting that body size-related traits respond almost independently to environmental heterogeneity. The effects of ecological factors analyzed in this study are discussed in order to elucidate the causal factors investigated （type of com- petition, crowding conditions and alternative host） affecting the election of the breeding site and/or the range of distribution of these cactophilic species.展开更多
基金supported by the National Natural Science Foundation of China(Nos.12272104,U22B2013).
文摘High-aspect-ratio aircraft are widely used in military and civilian fields,such as reconnaissance,surveillance,and attacks,due to their high lift-to-drag ratio,strong payload capability,significant endurance effect,and good stealth performance.However,compared to conventional aircraft,high-aspect-ratio aircraft are more susceptible to gust disturbances during flight.In response to this phenomenon,a full-scale dynamic model of a high-aspect-ratio unmanned aerial vehicle was developed.Considering the coupling among control surfaces,structural forces,and aerodynamic forces,along with sensor,actuator,and delay effects,an H_(∞)control law was designed using the principle of singular value energy flow reduction and weighted function,with a PID(Proportional-Integral-Derivative)control law for comparison.The two controllers were then subjected to pulse-response and jury stability tests.Finally,wind tunnel tests were conducted to investigate the gust alleviation principle,in which gust disturbances were generated using gust generators and control surface self-excitation.The results present that the average wing root bending moment and wing tip overload under the PID control law decrease by approximately 30%,while under the H_(∞)control law,both the average wing root bending moment and wing tip overload reduction rate exceed 50%,with peaks reaching 60%.This validates the feasibility and efficiency of the designed H_(∞)controller.
基金supported by the National Natural Science Foundation of China(Grant No.11602237)the Middleaged and Young Teachers’Basic Ability Promotion Project of Guangxi(Grant No.2022KY1070)。
文摘A computational and test method for calibrating the flight loads carried by aircraft wings is proposed.The wing load is measured in real-time based on the resistance and fiber Bragg grating strain gauges.The linear stepwise regression method is used to construct the load equations.The mean impact value algorithm is employed to select suitable bridges.In the ground calibration experiment,the wing load calculation equations in both forward and reverse installation states are calibrated.The correctness of the load equations was verified through equation error and inspection error analysis.Finally,the actual flight load of the wing was obtained through flight tests.
文摘In the highly fragmented landscape of central Europe, dispersal is of particular importance as it determines the long-term survival of animal populations. Dispersal not only secures the recolonization of patches where populations went extinct, it may also rescue small populations and thus prevent local extinction events. As dispersal involves different individual fitness costs, the decision to disperse should not be random but context- dependent and often will be biased toward a certain group of individuals （e.g., sex- and wing morph-biased dispersal）. Although biased dispersal has far-reaching consequences for animal populations, immediate studies of sex- and wing morph-biased dispersal in orthopterans are very rare. Here, we used a combined approach of morphological and genetic analyses to investigate biased dispersal of Metrioptera bicolor, a wing dimorphic bush-cricket. Our results clearly show wing morph-biased dispersal for both sexes of M. bicolor. In addition, we found sex-biased dispersal for macropterous individuals, but not for micropters. Both, morphological and genetic data, favor macropterous males as dispersal unit of this bush-cricket species. To get an idea of the flight ability ofM. bicolor, we compared our morphological data with that of Locusta migratoria and Schistocerca gregaria, which are very good flyers. Based on our morphological data, we suggest a good flight ability for macropters of M. bicolor, although flying individuals of this species are seldom observed.
基金supported by funding of Agencia Nacional de Promocion Cientifica y Tecnologica granted to V.PC.(PICT-2018-00753 and PICT-2015-0277)and to JJF(PICT-2016-2256).
文摘Insect flight is a complex trait involved in different behaviors,from the search for sexual partners,food,or breeding sites.Many studies have postulated the adaptive advantages of certain morphological traits in relation to increased flight capacity,such as low values of wing loading or high values of wing:thorax ratio and wing-aspect ratio.However,few studies have evaluated the relationship between variables related to flight and morphological traits in Drosophila.This work aimed to study morphological traits in males and females of two pairs of sibling species:Drosophila buzzati Patterson and Wheeler-Drosophila koeferae Fontdevila and Wasserman,and Drosophila melanogaster Meigen-Drosophila simulans Sturtevant,and to analyze its relationship with flight.We detected the highest proportion of flight time in D.koepferae and D.simulans compared to D.buzzati and D.melanogaster,respectively.Our results also revealed sexual dimorphism,with males exhibiting a higher proportion of flight time than females.Surprisingly,we did not find a general pattern to explain the relationship between morphology and the proportion of flight time because associations varied depending upon the analyses(considering all groups together or each sex-species combination separately).Moreover,these associations explained a low percentage of variation,suggesting that other nonmorphological components related to flight,such as physiological variables,should be taken into account.This work allowed us to show the variability and complexity of an aspect of flight,suggesting that the adaptive role of the morphological traits studied might have been overestimated.
文摘Changes in the environmental conditions experienced by naturally occurring populations are frequently accompanied by changes in adaptive traits allowing the organ- ism to cope with environmental unpredictability. Phenotypic plasticity is a major aspect of adaptation and it has been involved in population dynamics of interacting species. In this study, phenotypic plasticity （i,e., environmental sensitivity） of morphological adap- tive traits were analyzed in the cactophilic species Drosophila buzzatii and Drosophila koepferae （Diptera： Drosophilidae） considering the effect of crowding conditions （low and high density）, type of competition （intraspecific and interspecific competition） and cacti hosts （Opuntia and Columnar cacti）. All traits （wing length, wing width, thorax length, wing loading and wing aspect） showed significant variation for each environmental factor considered in both Drosophila species. The phenotypic plasticity pattern observed for each trait was different within and between these cactopbilic Drosophila species depending on the environmental factor analyzed suggesting that body size-related traits respond almost independently to environmental heterogeneity. The effects of ecological factors analyzed in this study are discussed in order to elucidate the causal factors investigated （type of com- petition, crowding conditions and alternative host） affecting the election of the breeding site and/or the range of distribution of these cactophilic species.
