Birds in nature exhibit excellent long-distance flight capabilities through formation flight,which could reduce energy consumption and improve flight efficiency.Inspired by the biological habits of birds,this paper pr...Birds in nature exhibit excellent long-distance flight capabilities through formation flight,which could reduce energy consumption and improve flight efficiency.Inspired by the biological habits of birds,this paper proposes an autonomous formation flight control method for Large-sized Flapping-Wing Flying Robots(LFWFRs),which can enhance their search range and flight efficiency.First,the kinematics model for LFWFRs is established.Then,an autonomous flight controller based on this model is designed,which has multiple flight control modes,including attitude stabilization,course keeping,hovering,and so on.Second,a formation flight control method is proposed based on the leader–follower strategy and periodic characteristics of flapping-wing flight.The up and down fluctuation of the fuselage of each LFWFR during wing flapping is considered in the control algorithm to keep the relative distance,which overcomes the trajectory divergence caused by sensor delay and fuselage fluctuation.Third,typical formation flight modes are realized,including straight formation,circular formation,and switching formation.Finally,the outdoor formation flight experiment is carried out,and the proposed autonomous formation flight control method is verified in real environment.展开更多
The ABCD law for the complex parameter q of the TEM00 Gaussian beam is generally not valid for high-order modes. It can be used for the high-order modes or their superposition when the spot size w in the virtual part ...The ABCD law for the complex parameter q of the TEM00 Gaussian beam is generally not valid for high-order modes. It can be used for the high-order modes or their superposition when the spot size w in the virtual part of the parameter q is substituted by the Rayleigh range ZR of a certain resonator. The focus characteristics of long distance flying optics are studied in this paper theoretically and experimentally for the TEMmn Gaussian beams between the two types of resonators without and with distortion. It is very important for the applications of the flying optical processing, the laser space craft and the spatial filter in the large laser project.展开更多
The influence of taper contamination on the static and dynamic characteristics of a slider is studiedin detail. Two models of taper contamination, including the effect of skew angle and the number of the railwith tape...The influence of taper contamination on the static and dynamic characteristics of a slider is studiedin detail. Two models of taper contamination, including the effect of skew angle and the number of the railwith taper contamination as well as the amount of contaminator on the taper,are investigated respectively. Anequivalent scheme is applied to evaluate the frequency responses with different flying attitudes in three de-grees of freedom. Ca1culations show that whether model is considered and how many tapers are contaminated,the static and dynamic characteristics of the slider change little in a very large contamination scale,but oncethe amount of contaminator exceeds some limit,the flying attitude of the slider is degraded catastrophically,which is easy to cause the slider crash. The skew angle,when it is large enough,may ameliorate or deterioratethe flying characteristics of the slider depending on the slider attitude when the transverse air flow passesthrough it.展开更多
基金This work was supported in part by the National Natural Science Foundation of China(Grant No.62233001)Shenzhen excellent scientific and technological innovation talent training project(Grant No.RCJC20200714114436040)the Basic Research Program of Shenzhen(Grant No.JCYJ20190806142816524).
文摘Birds in nature exhibit excellent long-distance flight capabilities through formation flight,which could reduce energy consumption and improve flight efficiency.Inspired by the biological habits of birds,this paper proposes an autonomous formation flight control method for Large-sized Flapping-Wing Flying Robots(LFWFRs),which can enhance their search range and flight efficiency.First,the kinematics model for LFWFRs is established.Then,an autonomous flight controller based on this model is designed,which has multiple flight control modes,including attitude stabilization,course keeping,hovering,and so on.Second,a formation flight control method is proposed based on the leader–follower strategy and periodic characteristics of flapping-wing flight.The up and down fluctuation of the fuselage of each LFWFR during wing flapping is considered in the control algorithm to keep the relative distance,which overcomes the trajectory divergence caused by sensor delay and fuselage fluctuation.Third,typical formation flight modes are realized,including straight formation,circular formation,and switching formation.Finally,the outdoor formation flight experiment is carried out,and the proposed autonomous formation flight control method is verified in real environment.
文摘The ABCD law for the complex parameter q of the TEM00 Gaussian beam is generally not valid for high-order modes. It can be used for the high-order modes or their superposition when the spot size w in the virtual part of the parameter q is substituted by the Rayleigh range ZR of a certain resonator. The focus characteristics of long distance flying optics are studied in this paper theoretically and experimentally for the TEMmn Gaussian beams between the two types of resonators without and with distortion. It is very important for the applications of the flying optical processing, the laser space craft and the spatial filter in the large laser project.
文摘The influence of taper contamination on the static and dynamic characteristics of a slider is studiedin detail. Two models of taper contamination, including the effect of skew angle and the number of the railwith taper contamination as well as the amount of contaminator on the taper,are investigated respectively. Anequivalent scheme is applied to evaluate the frequency responses with different flying attitudes in three de-grees of freedom. Ca1culations show that whether model is considered and how many tapers are contaminated,the static and dynamic characteristics of the slider change little in a very large contamination scale,but oncethe amount of contaminator exceeds some limit,the flying attitude of the slider is degraded catastrophically,which is easy to cause the slider crash. The skew angle,when it is large enough,may ameliorate or deterioratethe flying characteristics of the slider depending on the slider attitude when the transverse air flow passesthrough it.
