Showing papers in "Aerospace Science and Technology in 2021"

TL;DR: In this article, a parametric analysis based on experiments and then parametric optimization that involves hovering efficiency and structural weight in objective functions are performed by surrogate-based optimization. And the results of experiment and optimization indicate that the effects of weight penalty play a leading role at low disk loading and hence in this case, the one with lighter structure is superior.

TL;DR: This study shows both the common parts and the fundamental differences in the modeling, guidance, control, and control allocation for each hybrid-VTOL-UAV type.

TL;DR: In this article, a trapezoidal strut was used to inject fuel jet into a coaxial supersonic air stream to augment fuel mixing and diffusion downstream by intensifying vortices inside the domain.

TL;DR: In this paper, a thermal buckling analysis of annular/circular microplates, which are made from functionally graded Graphene nanoplatelets (GNP) reinforced porous nanocomposite is presented.

TL;DR: In this article, a B-spline-based generative adversarial network (GAN) is used to filter out unrealistic airfoils for a reduced design space that contains all relevant airfoil shapes.

TL;DR: In this article, experimental and numerical results of a propeller of 0.3 m diameter operated at 5000 RPM and axial velocity ranging from 0 to 20 m/s and advance ratio of 0 to 0.8 are presented as a preliminary step towards the definition of a benchmark configuration for low Reynolds number propeller aeroacoustics.

TL;DR: Time-varying formation tracking control problems for the multi-UAV system are investigated, where a leader with dynamic input is considered and continuous and discrete formation tracking protocols are proposed by utilizing the neighboring relative information.

TL;DR: Each UAV takes its own spot in a parallel formation, whereby each aircraft's speed asymptotically tends to the final cruising speed of the formation while the course angle tends to final course angle, which helps keep the formation stable and its geometry precise.

TL;DR: A system-level insight is provided through mathematical modelling, parameter analysis and feedback control into dynamics applications of morphing camber that shows that the active compliant segment can be used to stabilise the morphing aircraft by using feedback control.

TL;DR: A coordinate-free adaptive event-triggered sliding mode controller is proposed to ensure the closed-loop system to be uniformly ultimately bounded, in which an adaptive fuzzy logic system is utilized to compensate the disturbance.

TL;DR: A three-dimensional robust nonlinear cooperative guidance law for multiple missiles to simultaneously attack a maneuvering target at desired impact angles is proposed and the fixed-time stability is proved through the Lyapunov theory and bi-homogenous property.

TL;DR: A novel explainable deep neural network-based path planner for quadrotor to fly autonomously in unknown environment and a novel model explanation method is proposed based on the feature attribution to get better understanding of the trained model.

TL;DR: Simulation results are verified to intuitively reveal the good tracking performance of the introduced composite controller in terms of the finite-time error convergence, strong robustness, fault tolerance, and saturation elimination.

TL;DR: This work proposes a machine learning enabled, surrogate-based framework that replaces the expensive adjoint solver, without compromising on predicting predictive accuracy, and shows that multiple optimization problems can be solved with the same machine learning model with high accuracy, to amortize the offline costs associated with constructing the authors' models.

TL;DR: Simulations and experimental results as well as comparison analysis demonstrate that the proposed distributed optimal fusion method can effectively identify and predict kinematic model error and further achieve globally optimal fusion results, leading to improved performance for integrated MIMU/GNSS/CNS UAV navigation.

TL;DR: A deep reinforcement learning based motion planning method is proposed to solve the complex constrained motion planning problem of free-floating dual-arm space manipulator.

TL;DR: A method of combining Damped Least Squares (DLS) and feedback compensation is developed to avoid dynamic singularities due to the inverse kinematics equations, which can improve the premature phenomenon of particle swarm optimization (PSO).

TL;DR: In this paper, the effects of the incident shock Mach number (Ma) on the ignition delay times in two reflectors are systematically investigated, and the conical reflector creates an abrupt pressure rise in the apex, resulting in a 64.5% increase in the reflected shock velocity compared with the planar reflector.

TL;DR: This work constructs black-box algebraic models to substitute the traditional turbulence model by the artificial neural networks (ANN) rather than correcting the existing turbulence models in most of current studies, and shows the prospect of turbulence modeling by machine learning methods.

TL;DR: In this article, the studies on standard and swept cantilevered ramp injectors are provided to reveal the mixing enhancement mechanism and the formation of the complex shock wave system, and some parameters are also taken into consideration to evaluate the flow field properties, including the mixing efficiency, the intensity of streamwise vorticity and total pressure recovery efficiency.

TL;DR: A deep learning model, named Dual Convolutional Neural Network (Dual-CNN) for the aero-engine turbines is established, which is more accurate than GPR and ANN in predicting efficiency and torque, whose error is within an acceptable range of optimization.

TL;DR: In this paper, the propagation of stress waves in thick porous graphene-reinforced cylinders (TPGRCs) is investigated using a meshless solution based on an axisymmetric model and moving least squares (MLSs) interpolation functions.

TL;DR: An indoor automatic test platform for autopilot systems aiming to significantly improve the development efficiency and safety level of UAVs is presented and an automatic test framework is proposed to traverse test cases during real-time flight simulation and assess the test results.

TL;DR: An active fault-tolerant control system for spacecrafts subject to model uncertainty, external disturbance and actuator fault simultaneously, using a robust fault observer with a simple structure is proposed.

TL;DR: A finite-time fault-tolerant trajectory tracking control for a quadrotor system against external disturbances, parametric uncertainties and actuator faults without the need of fault diagnosis mechanism is proposed.

TL;DR: Research proves that the tailless configuration flapping wing UAV is able to sustain a stable flight, which provides a new design possibility for future researches.

TL;DR: The results confirm that an active control of the relative blade phase angles between propellers can effectively modify the directivity pattern of the system.

TL;DR: In this article, the authors presented vibration and thermal buckling behavior of an annular sandwich plate that consists of two asymmetric piezoelectric surface layers and one GPLRC core layer.

TL;DR: The proposed RFR-MIC model exhibits good performance compared with linear regression, k-nearest neighbors, artificial neural network, and standard Random Forest Regression, and the results show that flight information on multiple air routes can certainly improve the accuracy of flight departure delay prediction.

TL;DR: The approach combines “navigation aware” planning with multi-vehicle task assignment, generating a solution that depends on the sensors embarked onboard the UAVs, and can be naturally extended to account for multi-sensor-based navigation architectures and ground-infrastructure support.