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Purpose The purpose of this paper is to improve autonomous flight performance of an unmanned aerial vehicle (UAV) having actively sweep angle morphing wing using simultaneous UAV and flight control system (FCS) design. Design/methodology/approach An UAV is remanufactured in the ISTE Unmanned Aerial Vehicle Laboratory. Its wing sweep angle can vary actively during flight. FCS parameters and wing sweep angle are simultaneously designed to optimize autonomous flight performance index using a stochastic optimization method called as simultaneous perturbation stochastic approximation (SPSA). Results obtained are applied for flight simulations. Findings Using simultaneous design process of an UAV having actively sweep angle morphing wing and FCS design, autonomous flight performance index is maximized. Research limitations/implications Authorization of Directorate General of Civil Aviation in Turkey is crucial for real-time UAV flights. Practical implications Simultaneous UAV having actively sweep angle morphing wing and FCS design process is so beneficial for recovering UAV autonomous flight performance index. Social implications Simultaneous UAV having actively sweep angle morphing wing and FCS design process achieves confidence, high autonomous performance index and simple service demands of UAV operators. Originality/value Composing a novel approach to improve autonomous flight performance index (e.g. less settling and rise time, less overshoot meanwhile trajectory tracking) of an UAV and creating an original procedure carrying out simultaneous UAV having actively sweep angle morphing wing and FCS design idea.

Purpose Throughout an aircraft development process, the conceptual design phase is an extremely important milestone; hence, the quality and success of this step directly affect the overall cost and lead time of the project. Because of this fact, the purpose of this study is to provide outputs and suggestions to the designing engineer regarding the requirements for reducing overall design time as well as costs and creating an ideal design at the early phases of the project by optimizing the aircraft development process. Design methodology approach The system has been prepared parametrically and presents some performance specifications for the aircraft in the early phases of the design, for example, coefficients for lift CL as well as drag CD and weight as well as fuel estimations. The software uses a combination of well-known design techniques within just one platform in contrast to many other applications. Because of this feature, it is not needed to use different sub-platforms which would require an appropriate environment and even though would lead to complications with regard to the connectivity. The system also presents relevant information about the aircraft performance like velocity versus load factor (V-n) diagrams, maximum turn rate of climb, turn rate and climb angle graphs in contrast to many other open-source conceptual design platforms. Findings In this study, authentic General Dynamics F-16 Fighting Falcon and McDonnell Douglas F-15 Eagle data were used as input to the system, and advanced geometric and/or performance graphs were obtained and compared to the literature where a good agreement of the results was observed. These results with regard to the aircraft performance are typically product specific and quite rare in the literature. These data obtained by use of the software during the aircraft design are, thus, of major interest, especially for the design of new aerospace platforms. In this study, all of these graphs (especially the remarkable V-n diagram) are obtained on one platform. Originality value The aircraft conceptual design and analysis system software provides information and suggestions regarding the requirements for reducing the overall design time, reducing the design costs and creating an optimized design at the early phases of a project by optimizing the aircraft development process within just one convenient, that is, user friendly, platform, where it uses a combination of varying methodologies. Besides presenting one interface, which is quite typical for conceptual design tools, it allows applications of methods like vortex lattices and finite differences for obtaining aerodynamic performance parameters.

© 2022, Ismail Saritas. All rights reserved.In recent years, the interest in unmanned aerial vehicles (UAV) has increased. They have penetrated into all areas of life. However, studies on UAV control have been a frequently discussed topic by researchers. In this study, a hexarotor in which yaw flight is tried to be controlled by changing the arm lengths during flight (morphing) is discussed. The hexarotor mathematical model is linearly derived using Newton's equations of motion. The equations of motion are modeled using the state space model approach. Hexarotor has been drawn in Solidworks program in accordance with the reality of all morphing states. Morphing estimation and accordingly proportional-integral-derivative (PID) coefficients were estimated using Simultaneous Perturbation Stochastic Approximation (SPSA). SPSA was preferred because it converged to the optimum result faster than similar algorithms. Hexarotor simulations were performed in Matlab/Simulink environment. Hexarotor yaw flight stability was achieved by minimizing the SPSA generated cost function based on design performance criteria. The cost function converged in 3-4 iterations and approached the optimum result. Accordingly, the design performance criteria have also improved and successfully followed the given trajectory.

Quadrotor modeling has been done with collective and differential morphing. Quadrotor initial state and morphing states are drawn in the Solidworks program. Newton-Euler approximation was used for quadrotor modeling. The mass and moment of inertia values required for modeling and simulation were obtained from the Solidworks program. Matlab / Simulink environment and state-space model approaches are used for simulations. A simultaneous perturbation stochastic approximation (SPSA) algorithm was used to determine the quadrotor morphing rates. If the morphing state obtained by SPSA is not included in the values obtained from the drawings, here it is provided to find the moments of inertia with the method based on learning by using the data obtained with the Artificial Neural Network(ANN). Proportional Integral Derivative (PID) is used as the quadrotor control algorithm. PID coefficients are also determined by SPSA.

Aircraft are classified in two categories as manned and unmanned. Unmanned aerial vehicles are preferred for tasks such as search, rescue, research and observation. Conditions such as the payload it can carry and the flight time cause limits in the design of the aircraft. There was a need for aircraft with the same payload capacity that could penetrate areas where conventional aircraft could not navigate. This need and the applicability of systems that can change shape as a result of the studies of birds in nature have been the subject of research. In this study, the system design and control of a morphing quadrotor with the same payload capacity and the same flight time as the quadrotor unmanned aerial vehicle was carried out. It could be controlled with a PID controller, which is unstable. Thanks to the MEMS and obstacle detection sensors on the aircraft, it is aimed to energize the actuator, which will change the angle of intersection between the arms of the quadrotor, and to avoid obstacles in the closed environment and continue its course by reducing the angle. The effects of the configuration change, which occurred as a result of the shape change of the aircraft while cruising, on the flight characteristics were examined. These results are presented within the scope of this study., Hava araçları insanlı ve insansız olarak iki kategoride sınıflandırılır. İnsansız hava araçları arama, kurtarma, araştırma, gözlemleme gibi görevler için tercih edilmektedir. Taşıyabileceği faydalı yük, uçuş süresi gibi durumlar hava aracının tasarımında limitler oluşmasına sebep olmaktadır. Geleneksel hava araçlarının seyir edemediği alanlara nüfuz edebilecek ve aynı faydalı yük kapasitesinde hava araçlarına ihtiyaç olmuştur. Bu ihtiyaç, doğadaki kuşların incelemeleri sonucunda şekil değiştirebilen sistemlerin uygulanabilirliği araştırmalara konu olmuştur. Bu çalışmada dört rotorlu insansız hava aracı ile aynı faydalı yük kapasitesi ve aynı uçuş süresine sahip şekil değiştirebilen dört rotorlunun sistem tasarımı ve kontrolü gerçekleştirildi. Kararsız yapıda olan dört rotorlu PID (oransal integral türev) kontrolör ile kontrol edilebildi. Hava aracı üzerinde bulundurduğu MEMS (Mikro Elektro-Mekanik Sensör)’ler ve engel algılama sensörleri sayesinde dört rotorlunun kolları arasındaki kesişim açısını değiştirecek aktüatörün enerjilendirilmesi ile açı azaltılarak kapalı ortamda engellerden sakınması ve seyrine devam edebilmesi amaçlandı. Hava aracının seyir halinde şekil değiştirmesi neticesinde meydana gelen konfigürasyon değişikliğinin uçuş karakteristiğine olan etkileri incelendi. Elde edilen bu sonuçlar, bu çalışma kapsamında sunuldu.

Bu çalışmada, dört rotorlu bir İHA pervanesi üzerinde uçuş hızı ve dönme hızının pervanelerin aerodinamik performansı açısından büyük önem arz eden itme katsayısına olan etkilerini incelemek amacıyla sayısal araştırma gerçekleştirilmiştir. Bu amaçla 11-inç çapında bir pervane üzerinde dik uçuş koşulları altında farklı uçuş hızları ve dönüş hızlarında hesaplamalı akışkanlar dinamiği analizleri gerçekleştirilmiştir. Hesaplamalarda kullanılacak optimum ağ elemanı sayısını belirlemek için aynı zamanda ağdan bağımsızlık çalışması da gerçekleştirilmiştir. Sonuç olarak, k-ω SST türbülans modeli ile gerçekleştirilen analiz sonuçları, dönüş hızındaki artışın daha yüksek türbülans kinetik enerjisine sebep olduğunu göstermiştir. Ayrıca, yine dönüş hızındaki artışın deneysel sonuçlarla sayısal tahminlerin arasındaki farkı artırdığı, fakat uçuş hızından ise daha bağımsız hale getirdiği görülmüştür., In this article, a numerical investigation was performed on a quadrotor UAV propeller with the aim of examining effects of airspeed and rotational speed on thrust coefficient, which is one of the most important parameters on propeller aerodynamic performance. In that purpose, Computational Fluid Dynamics (CFD) analyses of an 11-inch propeller were carried out at different airspeeds and rotational speeds in vertical climbing flight condition. In order to have optimum number of mesh elements in computational domain, mesh independence analyses were also conducted. In conclusion, results of the analyses with k-ω SST turbulence model were shown that, increase in rotational speed was leaded to higher turbulent kinetic energy. Furthermore, higher rotational speeds also resulted in higher differences between numerical estimations and experimental data, but found to become more independent from airspeed.