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Steady flight of miniature fixed-wing unmanned aerial vehicle flocking by using biological algorithm

INTERNATIONAL JOURNAL OF MODELLING IDENTIFICATION AND CONTROL 2019年第3-4期32卷 219-225页

作者： Jia, Yongnan Li, Qing Zhang, Weicun Univ Sci & Technol Beijing Sch Automat & Elect Engn Beijing 100083 Peoples R China

This paper focuses on solving cohesive flocking problem from the biological point of view. Twelve variables are adopted to draw the kinematic characteristics of the fixed-wing UAV. A weighted and undirected graph is applied to describe the time-variant and distance-related interaction relationship among the UAVs. Based on the proposed model and the communication mechanism, a distributed cooperation approach is designed to force groups of miniature fixed-wing UAVs to be capable of collaboratively accomplishing such predefined task like a flock of birds. During the evolutionary process, three constraint conditions should be considered. The first one is that each UAV flies under small roll angle and small pitch angle. Second, one forward speed is necessary for the flight of each fixed-wing UAV. The last constraint condition is that the shorter the adjustment time, the better within the error margin of steady-state value. Three constraint conditions are skilfully taken as evaluation criteria to determine the communication network's coupling strength. Numerical simulations are provided to validate the feasibility of the proposed approach.

关键词： steady flight fixed-wing unmanned aerial vehicle cohesive flocking biological algorithm

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Prediction of Reference Crop Evapotranspiration in China's Climatic Regions Using Optimized Machine Learning Models

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WATER 2024年第23期16卷

作者： Hu, Jian Ma, Rong Jiang, Shouzheng Liu, Yuelei Mao, Huayan Sichuan Agr Univ Coll Water Resources & Hydropower Yaan 625014 Peoples R China Sichuan Univ State Key Lab Hydraul & Mt River Engn Chengdu 610065 Peoples R China Sichuan Univ Coll Water Resource & Hydropower Chengdu 610065 Peoples R China Jianyang Xintianfu Agr Technol Co Ltd Jianyang 641400 Peoples R China

The accurate estimation of reference crop evapotranspiration (ET0) is essential for crop water consumption modeling and agricultural water resource management. In the present study, three bionic algorithms (aquila optimizer (AO), tuna swarm optimization (TSO), and sparrow search algorithm (SSA)) were combined with an extreme learning machine (ELM) model to form three mixed models (AO-ELM, TSO-ELM, and SSA-ELM). The accuracy of the ET0 estimates for five climate regions in China from 1970 to 2019 was evaluated using the FAO-56 Penman-Monteith (P-M) equation. The results showed that the predicted values of the three mixed models and the ELM model fitted the P-M calculated values well. R2 and RMSE were 0.7654-0.9864 and 0.1271-0.7842 mmd-1, respectively, for which the prediction accuracy of the AO-ELM model was the highest. The performance of the AO-ELM combination5 (maximum temperature (Tmax), minimum temperature (Tmin), total solar radiation (Rs), sunshine duration (n)) was most significantly improved on the basis of the ELM model. The prediction accuracy for the stations in the plateau mountain climate (PMC) region was the best, while the prediction accuracy for the stations in the tropical monsoon climate region (TPMC) was the worst. In addition to the wind speed (U2) in the temperate continental climate region (TCC)-which was the largest variable affecting ET0-n, Ra, and total solar radiation (Rs) in the other climate regions were more important than relative humidity (RH) and wind speed (U2) in predicting ET0. Therefore, AO-ELM4 was selected for the TCC region (with Tmax, Tmin, Rs, and U2 as inputs) and AO-ELM5 (with Tmax, Tmin, Rs, and n as inputs) was selected for the TMC, PMC, SMC, and TPMC regions when determining the best model for each climate region with limited meteorological data.

关键词： reference crop evapotranspiration climate regions extreme learning machine biological algorithm modeling

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An approach based on biological algorithm for three-dimensional shape optimisation with fracture strength constrains

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COMPUTER METHODS IN APPLIED MECHANICS AND ENGINEERING 2008年第49-50期197卷 4383-4398页

作者： Peng, D. Jones, R. Monash Univ Dept Mech Engn CRC Railway Engn Clayton Vic 3800 Australia Monash Univ Dept Mech Engn DSTO Ctr Expertise Struct Mech Clayton Vic 3800 Australia

This paper presents an innovative approach to shape optimisation of three-dimensional damage tolerant structures for residual static strength. In this approach, a new and simple method, which we termed FAST (Failure Analysis of Structures), for estimating the stress intensity factor for cracks at a notch, as well as an extension of the biological algorithm was employed to study the problem of optimisation with fracture strength as the design objective. This method is ideal for use in structural optimisation as accurate results are obtained without the need to explicitly model a crack, i.e. it is only necessary to model the uncracked structure. Methodology and software to automate damage tolerance calculations were developed using CAD and FAST software. The numerical examples illustrate the use of the damage tolerance optimisation software and prove that stress optimised geometries are not necessarily optimised for residual static strength or fatigue life. (c) 2008 Elsevier B.V. All rights reserved.

关键词： Stress intensity factor Shape optimisation biological algorithm Finite element analysis

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Three-dimensional structure optimal design for extending fatigue life by using biological algorithm

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THEORETICAL AND APPLIED FRACTURE MECHANICS 2008年第1期49卷 26-37页

作者： Peng, D. Jones, R. Pitt, S. Monash Univ Dept Mech Engn Clayton Vic 3800 Australia Def Sci & Technol Org Air Vehicles Div Fishermans Bend Vic 3207 Australia

This paper presents some applications of a new structural shape optimization procedure for maximizing fatigue life or inspection intervals for damage tolerant structures. In this approach, a new and simple method, which we termed FAST (Failure Analysis of Structures), for estimating the stress intensity factor for cracks at a notch, as well as an extension of the biological algorithm was employed to study the problem of optimization with fatigue life as the design objective. Research by the authors has demonstrated that the optimum shape for minimizing stress is not necessarily the optimum shape for static strength or fatigue life of a damage tolerant structure. The examples are presented that highlight this difference. The optimal shapes for stress are compared with optimized shapes found for static strength with different crack lengths. These are also compared with optimized shapes found for maximum fatigue life. The choice of initial crack size was found to have a significant effect on the optimal shapes for the structures presented. (c) 2007 Elsevier Ltd. All rights reserved.

关键词： fatigue life shape optimization technique biological algorithm finite element analysis

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Residual strength optimisation of a vent hole in an aircraft component using a heuristic method

Residual strength optimisation of a vent hole in an aircraft...

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International Conference on Structural Integrity and Failure

作者： Das, Raj Jones, Rhys Univ Auckland Dept Mech Engn Auckland 1010 New Zealand Monash Univ Dept Mech Engn Melbourne Vic 3168 Australia

ISBN: (纸本)9783037851760

The paper presents application of damage tolerance optimisation principles to the design of industrial components. It is illustrated via design optimisation of a Fuel Flow Vent Hole (FFVH) located in the Wing Pivot Fitting (WPF) of an F-111 aircraft. The aim is to determine the shape of the cutout that will maximise its residual strength under the operating loading conditions. Damage tolerance shape optimisation is performed using a heuristic optimisation method known as the 'biological algorithm'. The maximum stress intensity factor (SW) for all of the cracks around the boundary of the optimal cutout is found to be significantly lower compared to that of the initial shape. This shows that an improved residual (fracture) strength is achieved for the optimal designs. The variability in SW around the cutout boundary is reduced, thereby making the shape more evenly fracture critical. The shapes of the residual strength optimal vent holes are found to depend on the initial crack sizes. It is also shown that a damage tolerance optimisation additionally produces a lighter WPF component design, which is highly desirable for aerospace industries.

关键词： Damage tolerance Residual strength Shape optimisation biological algorithm

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Human Society Inspired Routing For Wireless Sensor Network

Human Society Inspired Routing For Wireless Sensor Network

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36th Annual IEEE Conference on Local Computer Networks (LCN)

作者： Cheraghchi, Hamideh Sadat Nayebi, Abbas Inst Res Fundamental Sci IPM Sch Comp Sci Tehran Iran

ISBN: (纸本)9781612849287

biological systems have been an influential source of inspiration for designing localized and adaptive algorithm in networking domain. In this paper, we propose a human-inspired routing protocol for WSN utilizing ideas from Social Cognitive Theory (SCT). In this context, geographical aware sensors exhibit some localized human traits to higher their throughput while keeping in mind energy metric. The simulation results encourage the application of this model.

关键词： Wireless Sensor Network Geographical Routing Social Cognitive theory biological algorithm

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A CAD-based on biological method for designing optimal fatigue life

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STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION 2009年第3期37卷 295-304页

作者： Peng, D. Jones, R. Monash Univ Dept Mech Engn Clayton Vic 3800 Australia

This paper presents an innovative approach to shape optimisation of three-dimensional, damage-tolerant structures. In this approach, a new and simple method, which we termed Failure Analysis of Structures (FAST), is used to estimate the stress-intensity factor for cracks at a notch. The methodology and software used to automate damage-tolerance calculations are developed using computer-aided design and FAST codes. The worst crack locations are found by modeling many cracks along fractured critical edges of the structure by using FAST. This software is then used to evaluate damage-tolerance objective functions for optimisation algorithms. A particular stress-based biological growth method is employed to study the problem of optimisation with fatigue life as the design objective. This work confirms that a stress-optimised structure does not necessarily give the longest fatigue life by numerical examples.

关键词： Fatigue life Shape optimisation biological algorithm Finite element analysis

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Development of a 3D biological method for fatigue life based optimisation and its application to structural shape design

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INTERNATIONAL JOURNAL OF FATIGUE 2009年第2期31卷 309-321页

作者： Das, R. Jones, R. CSIRO Math & Informat Sci Melbourne Vic 3168 Australia Monash Univ Dept Mech Engn Clayton Vic 3168 Australia

Damage tolerance design philosophy assumes that numerous cracks can be present at various arbitrary locations in a structure, which makes fatigue life based shape optimisation very computationally intensive. As a result, there have been limited applications of fatigue life based optimisation. To address this, the paper presents a gradient-less 3D biological algorithm that uses fatigue life as the design objective for shape optimisation of damage tolerant structures. This formulation is used for optimisation with numerous 3D cracks located along the structural boundary. Fatigue life based shape optimisation is demonstrated via the problem of optimal design of 'a through-hole in a rectangular block made of linear elastic isotropic material under biaxial loading'. A range of different initial flaws were analysed to investigate the effects of crack parameters on optimal shapes. A semi-analytical method was employed for computation of the stress intensity factors (SIF). These were subsequently used for evaluating fatigue life by allowing the cracks to grow up to an acceptable final size. The optimum hole shapes were approximately elliptical with the aspect ratios being dependent on the initial and final crack sizes, and the local geometry. A significant enhancement in the fatigue life of a structural component is achieved. A fatigue life optimisation leads to the generation of a 'near uniform' fatigue critical surface. The effect of initial flaw aspect ratio on the optimal solutions was investigated, and it is found that the fatigue crack growth law governs the nature of variation of the optimal shapes. It is also shown that the fatigue life optimised shape can be quite different from the corresponding fracture strength or stress optimised solution. This emphasises the need to explicitly consider fatigue life as the design criteria for optimisation of damage tolerant structures. (C) 2008 Elsevier Ltd. All rights reserved.

关键词： Structural optimisation biological algorithm Damage tolerance Fatigue life Fracture strength Stress intensity factor

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Damage tolerance based design optimisation of a fuel flow vent hole in an aircraft structure

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STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION 2009年第3期38卷 245-265页

作者： Das, R. Jones, R. CSIRO Math & Informat Sci Clayton Vic 3168 Australia Monash Univ Dept Mech Engn Clayton Vic 3168 Australia

This paper investigates the design optimisation of a fuel flow vent hole (FFVH) located in the wing pivot fitting (WPF) of an F-111 aircraft assuming a damage tolerance design philosophy. The design of the vent hole shape is undertaken considering the basic durability based design objectives of stress, residual (fracture) strength, and fatigue life. Initially, a stress based optimised shape is determined. Damage tolerance based design optimisation is then undertaken to determine the shape of the cutout so as to maximise its residual strength and fatigue life. For stress optimisation, the problem is analysed using the gradient-less biological algorithm and the gradient-based nonlinear programming methods. The optimum designs predicted by the two fundamentally different optimisation algorithms agree well. The optimum shapes of the vent hole are subsequently determined considering residual strength and fatigue life as the distinct design objectives in the presence of numerous 3D cracks located along the vent hole boundary. A number of crack cases are considered to investigate how the crack size affects the optimal shapes. A semi-analytical method is employed for computation of the stress intensity factors (SIF), and an analytical crack closure model is subsequently used to evaluate the fatigue life. The 3D biological algorithm is used for designing the cutout profiles that optimise residual strength and fatigue life of the component. An improved residual strength/fatigue life (depending on the optimisation objective) is achieved for the optimal designs. The variability in SIF/fatigue life around the cutout boundary is reduced, thereby making the shape more evenly fracture/fatigue critical. The vent hole shapes optimised for stress, residual strength, and fatigue life are different from each other for a given nature and size of the flaws. This emphasises the need to consider residual strength and/or fatigue life as the explicit design objective. The durability based opt

关键词： Shape optimisation Damage tolerance Fatigue life Residual strength Stress intensity factor biological algorithm Nonlinear programming method Finite element analysis Industrial application

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