Numerical multidisciplinary optimization of aircraft with flight dynamic stability constraints

TL;DR: In this paper , the analysis of flying qualities of most often used unconventional configurations: canard, flying wing, three surface tandem wing and box wing is presented in terms of basic static stability and full 6 DoF dynamic analysis.

TL;DR: The paper presents lessons learned while designing, building and testing new UAVs in the configuration of the flying wing. It includes the use of 3D printing technology for manufacturing integrated pressure ports, investigation of the adverse yaw effect on the flying wing configuration and the effectiveness of winglet rudders in producing yawing moment.

TL;DR: A multidisciplinary analysis and structural optimization approach for the aeroelastic sizing of a UAV wing using open-source code integration is presented. The approach iteratively finds the optimal wing structure considering aeroelasticity effects and utilizes open-source software and frameworks for analysis and optimization.

Abstract: Purpose This paper aims to investigate trajectory optimization and optimal control of an e-vertical take-off and landing (eVTOL) unmanned aerial vehicle (UAV) during the transition phase. The transition is a maneuver that guides the aircraft from hovering to forward flight. Electric vertical flight vehicles suffer from insufficient energy density of onboard storage devices, which causes a decrease in range and endurance of the aircraft. Therefore, searching for energy-saving solutions is vital in extending the mission time. This study uses methods of optimal control, addressing a gap in the literature and a need to mitigate the restrictions caused by modern batteries. Design/methodology/approach The approach presented in this study is centered around optimal control and mathematical modeling of a quad-plane eVTOL UAV and consists of two phases. In the first phase, the authors used direct nonlinear optimal control for a simplified 3-degrees-of-freedom (DOF) model, along with a set of constraints on the motion, to derive optimal trajectory with the objective of minimizing energy consumed during transition. In the second phase, a feedback control system (linear-quadratic regulator) is used to realize the trajectory for a full 6-DOF model. The mathematical models used in the derivation of equation of motion are based on CFD and wind tunnel tests. Optimal control problem was transcribed in the ICLOCS2 software, and the optimization problem was solved with interior point optimizer (IPOPT) solver. Findings The results show a 70% decrease of energy consumption in comparison to a simple zero-pitch reference trajectory. The results indicate that the undertaken approach is valid, and that the method could be used with success to improve the range and energy consumption of the quad-plane. Moreover, this approach can be also applicable to other eVTOL aircraft types with transitional flight phases. Originality/value This paper postulates that the most savings for and already designed and existing eVTOL can be obtained by optimizing the transition maneuver, as this flight phase offers the most freedom in shaping the trajectory. The findings show that significant savings can be achieved, and it is a promising method to use in UAV mission planning to mitigate the challenge of insufficient electric energy onboard the aircraft.

TL;DR: In this article, the authors investigated the study of lateral dynamic stability in a flying wing aircraft with the engines in rear position and used the center of gravity location to determine on the Dutch roll damping curve a point beyond which the lateral model is instable.

TL;DR: The paper presents selected aspects of using the multidisciplinary optimization in aeronautical engineering with special focus onMultidisciplinary aircraft design.

TL;DR: The preliminary design of an aircraft wing through the use of a fully automated design environment, coupled with surrogate-based optimization, is presented and a parametric modeling framework was developed based on the seamless integration of several commercial software through built-in scripting languages.

TL;DR: 3D, multi-fidelity aerodynamic models used in morphing wing optimization reveal information unavailable with simplified models, and it is demonstrated that providing a smooth surface on wing gives substantial improvement in multi-purpose aircrafts.