Model Of UAV Research Articles

A209 通信途絶を考慮したマルチUAVシステムのフォーメーション制御に関する実験的検証(OS11 自律知能無人ビークルの運動と制御2)

This paper deals with an experimental validation of a formation control algorithm for a multi-UAV(Unmanned Aerial Vehicle) system by using LMI(Linear Matrix Inequality) conditions. First, we show a linearized model of UAVs like quadrotors, and then, we introduce a formation control algorithm based on a consensus algorithm, a leader-follower structure, graph theory and Lyapunov stability theorem for a liner system. Second, we show the control algorithm using Lyapunov theorem and LMI conditions in the case of intermittent communication. Then, experimental results show the stability of the proposed formation control even if some network links are disconnected.

EVALUATION OF SMALL UNMANNED AIRCRAFT FLIGHT TRAJECTORY ACCURACY / IŠORINIŲ FAKTORIŲ ĮTAKOS NEDIDELIO AUTONOMINIO ORLAIVIO SKRYDŽIO TRAJEKTORIJOS TIKSLUMUI VERTINIMAS

Today small unmanned aircraft are being more widely adapted for practical tasks. These tasks require high reliability and flight path accuracy. For such aircraft we have to deal with the chalenge how to compensate external factors and how to ensure the accuracy of the flight trajectory according to new regulations and standards. In this paper, new regulations for the flights of small unmanned aircraft in Lithuanian air space are discussed. Main factors, which affect errors of the autonomous flight path tracking, are discussed too. The emphasis is on the wind factor and the flight path of Dubbin’s trajectories. Research was performed with mathematical-dynamic model of UAV and it was compared with theoretical calculations. All calculations and experiments were accomplished for the circular part of Dubbin’s paths when the airplane was trimmed for circular trajectory flight in calm conditions. Further, for such flight the wind influence was analysed. Nedideli autonominiai orlaiviai yra vis plačiau pritaikomi praktinėms užduotims, kurioms reikalingas aukštas skrydžio patikimumas bei trajektorijos tikslumas, vykdyti. Kuriant bei naudojant tokius orlaivius, reikia vertinti egzistuojančių standartų bei taisyklių reikalavimus ir išorinių faktorių įtaką skrydžių trajektorijos tikslumui. Darbe aptariamos naujausios skrydžių autonominiais orlaiviais Lietuvoje taisyklės bei pagrindiniai faktoriai, darantys įtaką skrydžio trajektorijos paklaidoms. Darbe didžiausias dėmesys skirtas vėjo faktoriaus įtakos skrydžio trajektorijai vertinti, kai automatinio valdymo sistema nesiima koreguojamųjų veiksmų. Tyrimas atliktas remiantis teoriniais skaičiavimais bei traktuojant, kad orlaivis – taškinis kūnas. Šie rezultatai palyginti su gautaisiais panaudojus orlaivio dinaminį modelį.

Controller Optimization of Quadrotor UAV

Adjusting method of traditional PID controller is complicated. The controller obtained by adjusting method of traditional PID may be not optimal. Therefore, present paper utilized the genetic algorithm to optimize the PID controller parameter of roll channel of quadrotor UAV. According to the feature of lateral stability control model of quadrotor UAV, ascend time of system, steady state error, and weighted overshoot are chosen as objective function. In order to obtain the better control effect, penalty function is used to limit the oscillation of system. Simulation results show that PID controller designed by the genetic algorithm possess the excellent flexibility, adaptability and can produce the better control effect.

Experimental Research of Tandem-Scheme UAV Model Aerodynamic Characteristics

Abstract Tandem-wing aerodynamic scheme became widespread for tube launch UAV due to possibility of required flight performance realization under tight dimension constraints. In this work results of wind tunnel weight and visual tests of UAV model with wingspans about 1 m are presented. Model aerodynamic characteristics were defined by six-component wind tunnel balance at Mach number 0.075 and Reynolds number 187 000 calculated for one wing chord of 0.11 m. Model stagger (390, 490, 590 mm), rear wing dihedral angle (0°, -5°, -9°), forward-to-rear wingspan ratio (0.67; 0.9; 0.92; 1.24) were variable. It was determined that model is longitudinal and directional static stable, has high maximal lift-drag ratio (in range from 10.6 to 13.7) and acceptable maximal lift coefficient without flaps (from 1.05 to 1.09) and critical angle of attack (from 15.1 to 16.4°). Stagger increasing leads to zero or positive maximal lift-drag ratio increasing. If forward wing span is larger than rear wing span than stagger increasing is more effective with zero dihedral angle. If rear wing span is larger than forward wing span than stagger increasing is more effective with negative dihedral angle.

Investigation of the Aerodynamic Characteristics of an Aerofoil Shaped Fuselage UAV Model

This paper explains the fabrication of an UAV having aerofoil shaped fuselage using NACA 4416 profile and compare the result between the aerodynamic characteristics with that of the same model obtained from CFD investigation. Open circuit subsonic wind tunnel has been used to test the fabricated UAV model and collection of data. The wind tunnel is associated with Versatile Data Acquisition System (VDAS) to measure the lift & drag force coefficients and point surface pressures. This paper explains the design parameters and investigation of the aerodynamic characteristics of the fabricated ‘Aerofoil Shaped Fuselage’ UAV model. This type of model might be used for many military and civil applications like scientific data gathering, surveillance for law enforcement & homeland security, precision agriculture, forest fire monitoring, geological survey etc. The aerodynamic characteristics of Aerofoil Shaped Fuselage UAV model have been carried out at two different Reynolds Number (1.37 x 105 and 2.74 x 105 respectively) with different angles of attack from -3o to 18o. The stalling angle of this design is found at about 14o during experimental investigation. The aerofoil shaped fuselage UAV model might be used for designing the future UAV.

Sensor and Actuator FDI Applied to an UAV Dynamic Model

In this paper, an approach to isolate the sensor and control surface/actuator failures affecting the innovation of Kalman filter was proposed and applied to an UAV dynamic model. To diagnose if the fault is a sensor fault or an actuator fault, a two-stage Kalman filter (TSKF) insensitive to actuator faults is developed. In the proposed method, sensor faults are isolated by the normalized innovation of Kalman filter. Furthermore, an adaptive linear adaptive TSKF algorithm is used to estimate the loss of control effectiveness and the magnitude of degree of stuck faults in a UAV model. Control effectiveness factors and stuck magnitudes are used to quantify faults entering control systems through actuators. In the simulations, the longitudinal and lateral dynamics of the UAV model is considered, and detection and isolation of sensor and control surface/actuator failures are examined.

RobustD-Stability Controller Design for a Ducted Fan Unmanned Aerial Vehicle

This paper deals with the aerodynamic modeling of a small ducted fan UAV and the problem of attitude stabilization when the parameter of the vehicle is varied. The main aerodynamic model of the hovering flight UAV is first presented. Then, an attitude control is designed from a linearization of the dynamic model around the hovering flight, which is based on theH∞output feedback control theory withD-stability. Simulation results show that such method has good robustness to the attitude system. They can meet the requirements of attitude control and verify further the feasibility of such a control strategy.

Decentralized Control of Multi-UAVs for Target Search, Tasking and Tracking

This paper considers integrated target search, tasking and tracking using multiple fixed-wing UAVs in urban environments. The problem is to design autonomy for each individual UAV autonomous and distributed tasking. Control logic design based on finite state automaton (FSA) model, integrating the four modes of operations, i.e., takeoff mode, fly-to-AO (area of operation) mode, search mode and tracking mode, is developed. An efficient distributed multi-UAV target search algorithm is also presented. UAV guidance and control is built based on combined urban road map and target detection probability map information. For target tracking, by using geometric relations (relative position, orientations, speed ratio, and minimal turning radius), a systematic algorithm is developed to generate an optimal path online for a fixed-wing UAV to track a moving target. In addition, control method for a group of UAVs to keep track a target convoy is also addressed. Finally, the proposed decentralized algorithms are evaluated by simulations adopting a real UAV model.

RESEARCH OF WING DIHEDRAL ANGLE EFFECT ON AERODYNAMIC PERFORMANCE OF TANDEM-WING UNMANNED AERIAL VEHICLE

In the last decade folding tube launch UAV became common, for which aerodynamic scheme "tandem" is reasonable. By the time tandem-wing aerodynamic characteristics are researched much less than ones of traditional scheme. Particularly it concerns wing dihedral angle effect on lift-to-drag ratio about which no quantitative data were found.Forward or rear wing dihedral angle appearance result in circulation redistribution and changing of rear wing induced drag. Rear wing dihedral angle effect on longitudinal aerodynamic performance of tandem-wing UAV model was researched through wind tunnel experiment. Geometry variables were forward and rear wing spans, rear wing dihedral angle and longitudinal stagger. Lift, drag and longitudinal moment coefficients were defined.The possibility of lift-to-drag ratio increasing at cruise regime was proofed. Rear wing negative dihedral angle application is able to increase maximal lift-to-drag ratio by more than 1.0 or about 10 %.It was found that wing dihedral angle effectiveness depends from relation of forward and rear wing spans and from longitudinal stagger. Longitudinal stagger increasing results in dihedral angle effectiveness falling if forward wing span is higher than rear wing. For bigger rear wing span increasing of longitudinal stagger results in dihedral angle effectiveness gaining. The hypothesis was declared that proposes theoretical explanation of experimentally founded dependencies.Also dihedral angle appearance increases lift slope because of rear wing carrying capacity gain and has almost no influence on maximal lift coefficient.All dependencies founded for rear wing negative dihedral angle are correct for forward wing positive dihedral angle except the last one is increasing longitudinal and lateral stability.

Transient Characteristics of a Fuel Cell Powered UAV Propulsion System

In this paper, the transient characteristics of a fuel cell powered UAV propulsion system are investigated through effective time constants and step command responses in the time domain. A fuel cell powered UAV model is obtained by modifying the Aerosonde UAV model with a fuel cell system and an electric motor. The influence of the model parameters on the transient response characteristics of a fuel cell powered UAV propulsion system is studied through parametric studies. In addition, the linearized longitudinal model of a fuel cell powered UAV is compared with that of a conventional gas powered configuration to illustrate the impact of the significant time delay associated with a fuel cell system.

Optimal control and line‐of‐sight guidance formation flight

PurposeThe purpose of this paper is to design an integrated guidance and control design for a formation flight of four unmanned aerial vehicles to follow a moving ground target.Design/methodology/approachThe guidance law is based on the line‐of‐sight. The control is optimal. The guidance law is integrated with the optimal control law and is applied to a linear dynamic model.FindingsThe theoretical results are supported by the numerical simulations that illustrate a coordinated encirclement of a ground maneuvering target.Research limitations/implicationsA linear dynamic UAV model and a liner engine model were employed.Practical implicationsThis is expected to provide efficient coordination technique required in many civilian circular formation UAV applications; also the technique can be used to provide a safe environment required for the civil applications.Social implicationsThe research will facilitate the deployment of autonomous unmanned aircraft systems in various civilian applications such as border monitoring.Originality/valueThe research addresses the challenges of coordination of multiple unmanned aerial vehicles in a circular formation using an integrated optimal control technique with line‐of‐sight guidance.

Mathematical Model for Studying the Evolution of Multi-Role Unmanned Aerial Vehicle in Turbulent Atmosphere

The paper purpose is to present some aspects regarding the control system of unmanned aerial vehicle - UAV, used for local observations, surveillance and monitoring of interest area or as a training target for anti-aircraft systems. The calculus methodology allows a numerical simulation of UAV evolution in bad atmospheric conditions by using a nonlinear model, as well as a linear one for obtaining the guidance command. The UAV model which will be presented has six DOF (degrees of freedom), and an autonomous control system. This theoretical development allows us to build the stability matrix, command matrix and the control matrix and finally to analyze the stability of autonomous UAV flight. A robust guidance system, based on Kalman filter will be evaluated for different fly conditions and the results will be presented. The flight parameters and guidance will be analyzed. The paper is inspired by national project SAMO (Autonomous Aerial Monitoring System for Interest Areas of Great Endurance). Keywords: UAV, Simulation, Control, Guidance, Endurance, Surveillance, Monitoring, Kalman filter

RAPID ACQUISITION OF ENVIRONMENTAL INFORMATION AFTER ACCIDENTS WITH HAZARDOUS CARGO THROUGH REMOTE SENSING BY UAV

Abstract. The aim of the study was to present procedures of using remote sensing by UAV to aid in the rapid evaluation and monitoring of environmental impacts caused by accidents involving transport of dangerous cargoes on highways. From the data collected and the UAV model defined, it was developed a methodology of operating a UAV to generate the potential benefits identified in the application. A Mini UAV or Close Range class was considered appropriate. It was created the procedures for imaging, the emergency activation of an UAV, the generation parameters of the images and forms of environmental information extraction. The study does not eliminate the necessity of testing the technology for this application, but indicates the possibility of generating more detailed and faster information.

쿼드로터 무인기 비선형 적응 자세제어기 설계

본 논문은 쿼드로터 무인기의 비선형 적응 자세 제어기 설계에 대한 것이다. 쿼드로터 무인기는 4 개의 추력기를 갖는 불완전한 비선형시스템으로써 모델 파라미터가 변화하기 때문에 특별한 제어기가 필요하다. 본 연구에서는 산업 응용에 따른 페이로드의 변화에 따라서 무인기의 모델파라미터가 변화하더라도 페이로드에 따른 튜닝을 자동으로 할 수 있도록 적응제어기를 설계하였다. 특히, 무인기의 수학적 모델을 이용하여 비선형 적응제어기를 설계하였고 리야프노프 함수를 이용하여 이론적으로 안정성을 분석하였고 페이로드 변화에 따른 시뮬레이션을 통해서 제어기의 성능과 파라미터 추정법칙의 유효성을 입증하였다. This paper is discussed the design on non-linear adaptive attitude controller for quadrotor UAV. Quadrotor UAV featured to have four rotor, required the special controller to compensate for the model parameter uncertainties as the unstable nonlinear system. In this research, we designed the adaptive controller to compensate for the payload changes even though it is changed with industrial applications. Especially, based on the mathematical model of UAV, non-linear adaptive controller is suggested and the stability is verified using the Lyapunov function and finally proved its performance and effectiveness of update laws with various payload by simulation.

Distributed filtering over sensor networks for autonomous navigation of UAVs

The paper studies the problem of autonomous navigation of a multi-UAV system with the use of the Unscented Information Filter (UIF) and the Distributed Particle Filter (DPF). It is considered that $m$ UAV (helicopter) models are monitored by $n$ different ground stations. At each monitoring station a filter is used to track each UAV by fusing measurements which are provided by various UAV sensors, while by fusing the state estimates from the distributed local filters an aggregate state estimate for each UAV is obtained. The UIF and DPF estimated state vector is in turn used by a flatness-based controller that makes the UAV follow the desirable trajectories.

Static Analysis of a Small Scale Ducted-Fan UAV using Wind Tunnel Data

This paper discusses the mathematical modeling of a small scale ducted-fan UAV and examines its results in comparison to the wind tunnel test. A wind tunnel test is first performed, producing a substantial amount of test data. The acquired set of wind tunnel test data is then categorized and approximated as mathematical functions. Finally, the mathematically modeled forces and moments acting on the UAV are compared with the acquired wind tunnel data. The analysis involves a gradient-based algorithm and is applied to extract trim states with respect to various flight conditions. Consequently, a numerical analysis demonstrates that there exists a reasonable flight status with respect to airspeed.

Modeling and Hovering Control of an Ducted-Fan UAV in Low Speed Crosswind

National University of Defense Technology has begun a research program to investigate and test ducted-fan propeller architecture for UAV designing. Development of a prototype continues to support ongoing research in the area of autonomous systems. In this paper, we build a nonlinear dynamic model of Ducted-Fan UAV for verifying appropriate controller behavior, and design a hierarchical controller for hovering flight of the UAV.

Reactive collision avoidance of multiple realistic UAVs

PurposeUnmanned aerial vehicles (UAVs) have a wide variety of applications such as surveillance and search. Many of these tasks are better executed by multiple UAVs acting as a group. One of the main problems to be tackled in a high‐density UAV traffic scenario is that of collision avoidance among UAVs. The purpose of this paper is to give a collision avoidance algorithm to detect and resolve the conflicts of projected path among UAVs.Design/methodology/approachThe collision avoidance algorithm developed in the paper handles multiple UAV conflicts by considering only the most imminent predicted collision and doing a maneuver to increase the line‐of‐sight rate to avoid that conflict. After the collision avoidance maneuver, the UAVs fly to their destinations via Dubins shortest path to minimize time to reach destination. The algorithm is tested on realistic six degree of freedom UAV models augmented with proportional‐integral controllers to hold altitude, velocity, and commanded bank angles.FindingsThe paper shows, through extensive simulations, that the proposed collision avoidance algorithm gives a good performance in high‐density UAV traffic scenarios. The proposed collision avoidance algorithm is simple to implement and is computationally efficient.Practical implicationsThe algorithm developed in this paper can be easily implemented on actual UAVs.Originality/valueThere are only a few works in the literature that address multiple UAV collision avoidance in very high‐density traffic situations. This paper addresses very high‐density multiple UAV conflict resolution with realistic UAV models.

소형 연료전지 무인기의 전기추진시스템용 전력원 모델링 및 시뮬레이션

본 논문에서는 소형 무인기의 전기추진 시스템에 대한 모델링 및 전력 시뮬레이션에 관하여 기술하였다. 각 전력원 모델링 및 시뮬레이션을 위해 Matlab/Simulink를 사용하였고, 연료전지와 배터리를 주 전력원으로 사용하는 200 W급 전기추진 시스템에 대하여 4시간 30분의 비행 시험결과와 시뮬레이션 한 결과를 비교하였다. 그 결과, 시뮬레이션은 각 전력원의 성능 및 동특성을 적절히 모사하였고, 이를 통해 다른 급의 전기추진 시스템에 대한 전력특성변화를 예측하는 도구로 활용 가능함을 알 수 있었다. A modeling and power simulation of a small UAV's electric propulsion systems is described. Each power source is modeled and simulated in Matlab/Simulink and it is compared flight test data during 4 hr 30 min with simulation results about 200 W electric propulsion system using fuel cell and battery as a main power sources. In result, it is properly simulated performance and dynamic characteristic of each electric power source. Through this, it is revealed that the simulation is available as a means of predicting power characteristic variation for electric propulsion systems of different class.

Survey and application of sensor fault detection and isolation schemes

Model-based sensor fault detection, isolation and accommodation (SFDIA) is a direction of development in particular with UAVs where sensor redundancy may not be an option due to weight, cost and space implications. SFDIA via neural networks (NNs) have been proposed over the years due to their nonlinear structures and online learning capabilities. The majority of papers tend to consider single sensor faults. While useful, this assumption can limit application to real systems where sensor faults can occur simultaneously or consecutively. In this paper we consider the latter scenario, where it is assumed that a 1 s time gap is present between consecutive faults. Furthermore few applications have considered fixed-wing UAVs where full autonomy is most needed. In this paper an EMRAN RBF NN is chosen for modelling purposes due to its ability to adapt well to nonlinear environments while maintaining high computational speeds. A nonlinear UAV model is used for demonstration, where decoupled longitudinal motion is considered. System and measurement noise is also included in the UAV model as wind gust disturbances on the angle of attack and sensor noise, respectively. The UAV is assumed to operate at an initial trimmed condition of speed, 32 m/s and altitude, 1000 m. After 30 separate SFDIA tests implemented on a 1.6 GHz Pentium processor, the NN-SFDIA scheme detected all but 2 faults and the NN processing time was 97% lower than the flight data sampling time.