scholarly journals Research on Optimal Landing Trajectory Planning Method between an UAV and a Moving Vessel

2019 ◽  
Vol 9 (18) ◽  
pp. 3708 ◽  
Author(s):  
Liguo Tan ◽  
Juncheng Wu ◽  
Xiaoyan Yang ◽  
Senmin Song
Keyword(s):  
Numerical Approach ◽  
Key Factors ◽  
Simulation Experiments ◽  
Accuracy Improvement ◽  
Flight Path Angle ◽  
Calculation Process ◽  
Aerial Vehicle ◽  
Heading Angle ◽  
Optimal Approach ◽  
Landing Trajectory

The location, velocity, and flight path angle of an autonomous unmanned aerial vehicle (UAV) landing on a moving vessel are key factors for an optimal landing trajectory. To tackle this challenge, this paper proposes a method for calculating the optimal approach landing trajectory between an UAV and a small vessel. A numerical approach (iterative method) is used to calculate the optimal approach landing trajectory, and the initial lead is introduced in the calculation process of the UAV trajectory for the inclination and heading angle for accuracy improvement, so that the UAV can track and calculate the optimal landing trajectory with high precision. Compared with the variational method, the proposed method can calculate an optimal turning direction angle for the UAV during the landing. Simulation experiments verify the effectiveness of the proposed algorithm and give optimal initialization values.

Trajectory optimization of unmanned aerial vehicle in dynamic soaring

2016 ◽  
Vol 231 (10) ◽  
pp. 1779-1793 ◽  
Author(s):  
Bing-Jie Zhu ◽  
Zhong-Xi Hou ◽  
Hua-Jiang Ouyang
Keyword(s):  
Unmanned Aerial Vehicle ◽  
Wind Field ◽  
Trajectory Optimization ◽  
Research Work ◽  
Flight Path ◽  
Dynamic Soaring ◽  
Gradient Wind ◽  
Flight Path Angle ◽  
Aerial Vehicle ◽  
Heading Angle

An aircraft can extract energy from a gradient wind field by dynamic soaring. The paper presents trajectory optimization of an unmanned aerial vehicle for dynamic soaring by numerical analysis and validates the theoretical work through flight test. The collocation approach is used to convert the trajectory optimization problem into parameters optimization. The control and state parameters include lift coefficient, bank angle, positions, flight path angle, heading angle, and airspeed, which are obtained from the parameter optimization software. To validate the results of numerical simulation, the dynamic soaring experiment is also performed and experimental data are analyzed. This research work shows that the unmanned aerial vehicle can gain enough flight energy from the gradient wind field by following an optimal dynamic soaring trajectory. Meanwhile, the variation of flight path angle, heading angle, and airspeed has a significant influence on the energy transform. The solution can provide theoretical guide to unmanned aerial vehicles for extracting maximum energy from gradient wind fields.

scholarly journals R-DFS: A Coverage Path Planning Approach Based on Region Optimal Decomposition

2021 ◽  
Vol 13 (8) ◽  
pp. 1525
Author(s):  
Gang Tang ◽  
Congqiang Tang ◽  
Hao Zhou ◽  
Christophe Claramunt ◽  
Shaoyang Men
Keyword(s):  
Path Planning ◽  
Google Earth ◽  
Simulation Experiments ◽  
Minimum Width ◽  
Coverage Path Planning ◽  
Optimal Paths ◽  
Planning Approach ◽  
Polygonal Area ◽  
Aerial Vehicle ◽  
Working Distance

Most Coverage Path Planning (CPP) strategies based on the minimum width of a concave polygonal area are very likely to generate non-optimal paths with many turns. This paper introduces a CPP method based on a Region Optimal Decomposition (ROD) that overcomes this limitation when applied to the path planning of an Unmanned Aerial Vehicle (UAV) in a port environment. The principle of the approach is to first apply a ROD to a Google Earth image of a port and combining the resulting sub-regions by an improved Depth-First-Search (DFS) algorithm. Finally, a genetic algorithm determines the traversal order of all sub-regions. The simulation experiments show that the combination of ROD and improved DFS algorithm can reduce the number of turns by 4.34%, increase the coverage rate by more than 10%, and shorten the non-working distance by about 29.91%. Overall, the whole approach provides a sound solution for the CPP and operations of UAVs in port environments.

The simulation of flight trajectory based on quasi-Newton and mesh simplification

2019 ◽  
Vol 33 (26) ◽  
pp. 1950311
Author(s):  
Yangyong Guo ◽  
Xiaoling Gao ◽  
Juan Wei ◽  
Jierui Wang ◽  
Mei Li ◽  
...  
Keyword(s):  
Prediction Accuracy ◽  
Simulation Experiment ◽  
Prediction Method ◽  
Mesh Simplification ◽  
Flight Trajectory ◽  
Key Factors ◽  
Aircraft Flight ◽  
Factors Influencing ◽  
Calculation Process ◽  
Quasi Newton

To address the problem of low accuracy of aircraft flight trajectory, a new prediction method for flight trajectory is proposed based on the quasi-Newton and mesh simplification algorithm. This method firstly proposes the calculation method of 3D aircraft flight trajectory, and simplifies the calculation process with mesh simplification algorithm. At the same time, the prediction accuracy is further improved with the quasi-Newton algorithm. At last, through the simulation experiment, we have made a deep study of the key factors influencing the prediction method. The result has shown that the method has good adaptability.

scholarly journals Comparative Analysis of Splash Erosion Devices for Rainfall Simulation Experiments: A Laboratory Study

Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1228 ◽  
Author(s):  
María Fernández-Raga ◽  
Julián Campo ◽  
Jesús Rodrigo-Comino ◽  
Saskia D. Keesstra
Keyword(s):  
Rainfall Simulation ◽  
Key Factors ◽  
Erosion Process ◽  
Rain Intensity ◽  
Significant Relation ◽  
Simulation Experiments ◽  
Rainfall Characteristics ◽  
Splash Erosion ◽  
Simulated Rain ◽  
Set Up

For the study of soil erosion it is important to set up the experiments well. In the experimental design one of the key factors is the choice of the measurement device. This is especially important when one part of the erosion process needs to be isolated, such as for splash erosion. Therefore, the main aim of this research is to list the general characteristics of the commonly used splash erosion devices and to discuss the performance, to be able to relate them, and make suggestions regarding their use. The devices we selected for this comparative comparison were: the splash cup, funnel, Morgan tray, Tübingen cup, tower, and the gutter. The devices were tested under the same conditions (rainfall characteristics, slope, and soil type) to assess their hydrological response under different intensities of simulated rainfall. All devices were installed on a sloping plot (10°) with sandy soil, and were exposed to 10 min. of simulated rain with intensities ranging from 60 to 172 mm/h to measure the splashed sediment, and to describe problems and differences among them. The results showed that the Tübingen cup was the best performing device to measure kinetic energy of the rain, but, because of its design, it is not possible to measure the detached splashed sediment under natural (field) conditions. On the other hand, the funnel device showed a significant relation with rain intensity because it loses little sediment to washing. In addition, the device is easy to use and cheap. Therefore, this device is highly recommended to estimated splash erosion. to the good performance measuring the actual splash erosion, because it loses little sediment by washing. The device is also cheap and easy to install and manage.

scholarly journals Fault-tolerant communication topology management based on minimum cost arborescence for leader–follower UAV formation under communication faults

2017 ◽  
Vol 14 (2) ◽  
pp. 172988141769396 ◽  
Author(s):  
Guoqiang Wang ◽  
He Luo ◽  
Xiaoxuan Hu ◽  
Huawei Ma ◽  
Shanlin Yang
Keyword(s):  
Graph Theory ◽  
Fault Tolerant ◽  
Minimum Cost ◽  
Formation Flight ◽  
Communication Cost ◽  
Topology Management ◽  
Simulation Experiments ◽  
Communication Topology ◽  
Aerial Vehicle ◽  
Management Method

A novel fault-tolerant communication topology management method for the leader–follower unmanned aerial vehicle (UAV) formation is proposed to minimize the formation communication cost while keeping the formation shape, even in the case of communication faults during the formation flight. This method is based on Edmonds’ algorithm for the minimum cost arborescence problem in graph theory. When a formation shape is given before the formation flight, this method can get the optimal initial communication topology with the minimum formation communication cost for keeping the formation shape. When some communication faults occur during the formation flight, which will cause the formation shape cannot be kept, this method can reconfigure the communication topology in time to guarantee the safety of all UAVs and recover the formation shape, and then it can reoptimize the communication topology by UAV position reconfiguration in the formation shape to minimize the formation communication cost for continuously keeping the formation shape. The effectiveness of this method is demonstrated through several simulation experiments.

Probabilistic Flow Modelling Approach for Kick Tolerance Calculations

2017 ◽  
Author(s):  
Dalila Gomes ◽  
Knut Steinar Bjørkevoll ◽  
Johnny Frøyen ◽  
Kjell Kåre Fjelde ◽  
Dan Sui ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Pore Pressure ◽  
Flow Model ◽  
Transient Flow ◽  
Probabilistic Approach ◽  
Numerical Approach ◽  
Free Form ◽  
Maximum Pressure ◽  
Fracture Pressure ◽  
Calculation Process

During drilling, there must be an evaluation of the maximum pressure that the formation can handle during a well kill scenario. This will depend on various parameters like fracture pressure, pore pressure, kick volume and several other factors. The depth of the next planned hole section will depend on if a kick of a certain size can be handled safely. This evaluation is often referred to as performing kick tolerances. When starting to drill a section, one will take a leak off test to get an indication of the fracture pressure at the last set casing shoe and this will be important information for the kick tolerance results. For HPHT wells the margin between pore and fracture pressures will be small, and one often has to resort to using transient flow models to perform the kick tolerances. However, there are many uncertain parameters that are affecting the results. Some examples here are pore pressure, type of kick and kick distribution. There is a need for trying to incorporate the uncertainty in the calculation process to give a better overview of possible outcomes. This approach has become more and more popular, and one example here is reliability based casing design. This paper will first describe the kick tolerance concept and its role in well design planning and operational follow up. An overview of all parameters that can affect the results will be given. In water based mud, the gas kick will be in free form yielding higher maximum casing shoe pressures compared to the situation when oil based mud is used where the kick can be fully dissolved. Then it will be shown how both an analytical and a transient flow model can be used in combination with the use of Monte Carlo simulations to generate a probabilistic kick tolerance calculation showing possible outcomes for maximum casing shoe pressure for different kick volumes. Here uncertain input parameters that can affect the calculation result will be drawn from statistical distributions and propagated through the flow model to estimate the casing shoe pressure. Multiple runs will be needed in the Monte Carlo simulation process to generate a distribution of the maximum casing shoe pressure. This will demand a rapid and robust flow model. The resulting maximum casing shoe pressure distribution will then be compared against the uncertainty in the fracture pressure at the last set casing shoe to yield a probability for inducing losses. The numerical approach for predicting well pressures and a schematic of the total calculation process will be given. Emphasis will also be put on discussing how this should be presented to the engineer with respect to visualization and communication. It will also be shown that one of the strengths of the probabilistic approach is that it is very useful for performing sensitivity analysis such that the most dominating factors affecting the calculation results can be identified. In that way, it can help in interpreting and improving the reliability of the kick tolerance simulation results.

scholarly journals Planar Smooth Path Guidance Law for a Small Unmanned Aerial Vehicle with Parameter Tuned by Fuzzy Logic

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Yang Chen ◽  
Jianhong Liang ◽  
Chaolei Wang ◽  
Yicheng Zhang ◽  
Tianmiao Wang ◽  
...  
Keyword(s):  
Fuzzy Logic ◽  
Unmanned Aerial Vehicle ◽  
Oscillation Amplitude ◽  
Mathematical Expression ◽  
Path Following ◽  
Simulation Experiments ◽  
Guidance Law ◽  
Smooth Path ◽  
Aerial Vehicle ◽  
The Stability

A guidance law has been designed to guide the small unmanned aerial vehicle towards the predefined horizontal smooth path. The guidance law only needs the mathematical expression for the predefined path, the positions, and the velocities of the vehicle in the horizontal inertial frame. The stability of the guidance law has been demonstrated by the Lyapunov stability arguments. In order to improve the path following performance, one of the parameters of the guidance law is tuned by using the fuzzy logic which will still keep its stability. The simulation experiments in the Matlab/Simulink environment to realize the square-, circular-, and the athletics track-style paths following are given to verify the effectiveness of the proposed method. The simulation results show that the path following performance will be improved with smaller overshoot and oscillation amplitude and shorter arrival time with the parameter tuned.

UAV Collision Detection Algorithm Design Based on Circle Overlapping Test

2012 ◽  
Vol 229-231 ◽  
pp. 1487-1491
Author(s):  
N.F.M. Radzi ◽  
M. Mubin ◽  
N.A. Rahim ◽  
N. Mokhtar
Keyword(s):  
Collision Detection ◽  
Algorithm Design ◽  
Detection Algorithm ◽  
Two Dimensional ◽  
Straight Path ◽  
Conflict Problem ◽  
Aerial Vehicle ◽  
Heading Angle ◽  
Conflict Information ◽  
Near Future

Each UAV require a robust collision detection in its operating system to ensure it can aware the potential of collision in near future. Collision detection algorithm is one of the important parts that need to be concerned in the CAS. This paper proposes a design of collision avoidance algorithm for unmanned aerial vehicle based on circle overlapping test. Assuming two moving UAV are flying in the same altitude and in straight path within a two dimensional plane as conflict problem. Both UAV are cooperative aircrafts which communication of position, heading angle, waypoint, and velocity are allowed. The proposed algorithm will determine the collision potential between the surrounding intruders according to the conflict information.

Offloading Operability With Heading Control of Side-by-Side Moored FLNG and LNGC

2012 ◽  
Author(s):  
Hyun Joe Kim ◽  
Hyun-Uk Kwak ◽  
Jonghun Lee ◽  
Se Eun Kim ◽  
Jong Soo Seo
Keyword(s):  
Relative Motion ◽  
Wind Wave ◽  
Model Tests ◽  
Shielding Effect ◽  
Key Factors ◽  
Natural Period ◽  
Heading Control ◽  
Heading Angle ◽  
The Impact ◽  
Drift Forces

In this study, a series of model tests was performed and the effect of the heading control on the offloading operability of side-by-side moored vessels in multidirectional environments was investigated. During the tests, hawser tensions, fender loads, and relative motions between two vessels were focused, which are the key factors defining the offloading operability. Basically, the heading control is designed to maintain the FLNG (LNG FPSO)’s heading at between wind wave and swell. In the model tests, several heading angles were selected to investigate the impact of the heading control on the offloading operability, which includes the heading angles aligned with swell and between swell and wind wave. The loading conditions of the FLNG and LNGC were chosen to have a similar roll natural period, and the period of swell was also selected close to the roll natural period, which realizes an worst situation. The model tests proved that heading control improves the offloading operability in the multi-directional environments. However, in the test, as vessel’s heading angle approaches to the direction of swell, the LNGC is exposed to wind wave as much as to increase the relative motion between the two vessels and deteriorate the offloading operability. In the model test campaign, the motion RAOs and horizontal drift forces/moment due to waves for the side-by-side moored vessels were measured and compared with the analytical calculations, which show the strong shielding effect on the wind wave by the FLNG.

Sign in / Sign up

Export Citation Format

Share Document