Rotary Aircraft Research Articles

扑翼飞行器一致性编队控制二阶系统的研究

近年来，随着科学技术的发展，扑翼飞行器的研究受到了领域更多人的重视。由于扑翼飞行器与固定翼和旋翼飞行器相比具有明显的优势，许多国家斥巨资对此项目进行了各项基础研究，大大加强了在此领域的研究力度。一致性编队控制作为扑翼飞行器的一个重要研究分支，受到了不同领域的学者们越来越多的关注。将扑翼飞行器看成一个智能体，则本文就着重对多智能体一致性编队控制系统做了如下一些工作：首先，介绍了研究该课题应具备的代数图论知识，并运用图论与矩阵分析描述了多智能体之间的拓扑结构，介绍了验证一致性稳定性的理论，以及一阶系统、带领导者的二阶系统的控制协议。其次，介绍了多智能体的一阶系统、二阶系统的模型以及领导者的概念，并分别给出了控制协议。其中，带领导者的二阶系统给出了两种不同情况的模型，分别为：仅有一位主领导者的二阶系统和多位领导者并行的二阶系统。最后，对于所给出的具有一位主领导者的多智能体二阶一致性编队控制系统，运用数学的方法，从理论上证明了模型的正确性，同时利用计算机模拟仿真的结果也验证了理论的正确性。 In recent years, with the development of science and technology, more and more people pay more attention to flapping wing aircraft. Due to the obvious advantages of flapping wing aircraft compared with fixed wing and rotor aircraft, many countries have invested huge sums of money to carry out basic research on this project, which has greatly strengthened the research in this field. Consistent formation control, as an important research branch of flapping wing aircraft, has attracted more and more attention from scholars in different fields. The flapping wing aircraft is considered as an agent, and the following work is focused on the multi-agent consensus formation control system: first of all, the article introduces the knowledge of algebraic graph theory for studying the subject and describes the topological structure of multi-agent with the graph theory and matrix analysis. It also elaborates the theory of verifying the stability of the consistency, the first-order system and the control protocol of the two-order system with leaders. Secondly, the first order system of multi-agent, the model of two-order system and the concept of leader are introduced, and the control protocol is given respectively. Among them, the two-order system with leader gives two different models, namely, the two-order system with only one leader, and the two-order system with many leaders. Finally, for the two-order consensus formation control system with one master leader, the mathematical model is used to prove the correctness of the model. At the same time, the correctness of the theory is verified by computer simulation results.

混合式VTOL UAV动力学建模与仿真

混合式VTOL UAV是简单的将四旋翼和固定翼无人机结合在一起，不仅具备四旋翼飞行器的垂直起降、可悬停的特点，还具备固定翼飞行器的航程远、平飞速度快等特点，具有很重要的应用价值。在该飞行器布局中，四旋翼负责提供升力，工作在起飞和降落阶段；在起飞后则转换为固定翼飞行模式。本文建立了飞行器的动力学方程，并搭建Simulink仿真平台采用PID闭环控制的方法对其进行了仿真，结果表明设计的PID控制器能够使系统的输出有较好的稳定性。 Hybrid VTOL UAV is a simple combination of quad rotor and fixed wing UAV. It not only has the characteristics of the vertical take-off and landing of the quad rotor aircraft, but also has the characteristics of long distance and high speed, so it has important application value. In the layout of the aircraft, the quad rotor is responsible for providing lift, working in the take-off and landing phase; after taking-off it will be converted to fixed wing flight mode. This paper establishes the dynamic equation of the aircraft, and build a Simulink simulation platform by using the method of PID closed loop control of the simulation. The results show that the design of the PID controller can make the output of the system has a good stability.

水空両用マルチコプタの開発

水空両用マルチコプタの開発

Research on the Unmanned Aerial Vehicle Adaptive Control System based on Fuzzy Control and Chaos Mechanics

In this paper, we conduct research on the unmanned aerial vehicle adaptive control system based on fuzzy control and chaos mechanics. Four rotor aircraft is a kind of nonlinear systems with underactuated, strong coupling characteristic. Although in existing research, through the design of the control algorithm effectively inhibits both for flight control effect, but not fundamentally eliminate the effect of aircraft. Dynamic model of unmanned helicopter flight control system design is very approximate, need to gradually improve the modeling accuracy, so as to get the exact autonomous flight control, so you need to practice constantly required to modeling in the flight information, so the unmanned helicopter flight control system to have the ability to retrieve information modeling. This paper proposes the new idea on the issues that will be meaningful.

Stability contour maps with barrel cutters considering the tool orientation

The geometry of rotary aircraft engine components is usually defined by thin mechanical elements and complex surfaces that are only achievable by 5-axis machining due to either limited access or the design itself. Such thin-walled characteristics make these components susceptible to vibrations while machining and usually require careful manipulation of the toolpath parameters to minimize cutting forces and vibration. Moreover, the tool suppliers’ approach leans towards the feature-build design of cutter geometry to increase the productivity and quality of a machined surface. Some examples of those recent improvements for rotary aircraft engine components are barrel-shaped tools that attempt to increase the contact radius on the tool-part interface to minimize step-over while conserving the scallop height to meet roughness tolerances. This research aims to fill a gap in the current literature by proposing a stability model for barrel-shaped tools. Stability contour maps make use of a mechanistic dynamic force model for barrel-shaped tools. The force model is also capable of including tool runout and orientation angles, tilt and lead, as named in most CAM software. By simulating dynamic forces on the time domain, a contour map is presented to address unstable vibrations. Since forced vibrations and surface location error (SLE) may also appear when milling aircraft parts, SLE and surface roughness are also determined. Finally, given the complexity and number of parameters, validation of the stability maps is performed through experimental chatter tests using a thin wall component.

회전익항공기 상태감시시스템 임계값 최적화를 통한 비행안전성 확보기술

회전익항공기 상태감시시스템 임계값 최적화를 통한 비행안전성 확보기술

The Attitude Signal Processing of Four Rotor Aircraft based on a Kalman Filter

This paper puts forward Kalman filter algorithm to improve the accuracy and the stability of four rotor aircraft control. The algorithm principle is that making use of covariance to estimate the system optimal output.The flight and control theory of four rotor aircraft is first analysed, furthermore, it is found that the attitude angle has the biggest influence to its control. Then, the Kalman filter model is established for processing attitude angle information from gyro and accelerometer sensors. Finally, the algorithm is compared with complementary filter. The flight conditions is simulated in different flight environment, it is shown that Kalman filter algorithm can improve the precision and real time more greatly in attitude angle acquisition.

Techno-economic viability assessments of greener propulsion technology under potential environmental regulatory policy scenarios

Sustainability of the aviation industry, as any other industry, depends on the elasticity of demand for the product and profitability through minimising operating costs. Of paramount importance is assessing and understanding the interdependency and effects of environmentally optimised solutions and emission mitigation policies.This paper describes the development and application of assessment methodologies to better understand the effects of environmental taxation/energy policies aimed at environmental pollution reduction and the future potential economic impact they may have on the adaptation of “greener” novel technologies. These studies are undertaken using a Techno-economic Environmental Risk Assessment approach. The methodology demonstrated allows the assessment of the economic viability of new technologies compared to conventional technologies, for various CO2 emission taxation and fuel price scenarios. It considers relative increases in acquisition price and maintenance costs.A study undertaken as a ‘proof of concept’ compares a Counter Rotating Open Rotor aircraft with a conventional aircraft for short range operations. It indicates that at current fuel price and with no carbon taxation, a highly fuel efficient technology, such as the one considered, could be rendered economically unviable.The work goes on to demonstrate that in comparison to the conventional aircraft, any economic benefits that may be accrued from improvement in fuel consumption through such a technology, may well be negated through increases in acquisition price and maintenance costs. The work further demonstrates that if policy makers want to direct the industry towards greener propulsion solutions, then an increase in CO2 emission taxation may be appropriate.

Design and Research on Mechanism of Bionic Flapping-wing Air Vehicle

The fly mechanism and motion characteristics of the birds were analyzed. By the bionics principle, a new bionic flapping wing mechanism was proposed in order to imitate the motion of bird wing. The virtual prototype of this mechanism was established through ADAMS, then the kinematic simulation analysis was applied to the prototype in order to validate the feasibility of this mechanism. And a computational fluid dynamics software, named Fluent was employed to analyze the aerodynamic force of bionic wing. These results shorten the period of manufacturing of flapping wing mechanism, and can provide theoretical basis for the research and manufacture of bionic flapping wing robot. The Flapping-wing Air Vehicle (FAV) based on bionics is a sort of new aircraft which imitates birds. Compared with the traditional fixed wing and rotor aircraft, setting the lift, hovering and push functions in a flapping wing system is the main characteristics of Flapping-wing Air Vehicle and it has strong maneuverability (1). Flapping-wing Air Vehicle has advantages of high maneuverability, low noise, low cost, multifunction and potential applications to the modern war. In view of the FAV has great advantages in military and civilian applications, research institutions and universities around the world design various types of FAV. Research on this field has also been conducted in China. At present, the successful flight of FAV mostly adopts single crank rocker mechanism, such as MAV developed by northwestern polytechnical university (2). Although single crank rocker mechanism can achieve predetermined flapping frequency and angle, but itself is a symmetrical structure. The motion of both sides wings is asymmetry in the process of flapping flight and affects the flight stability and security. This paper analyzes the movement characteristics of bird wings from the perspective of bionics. A symmetric double sections flapping wing mechanism is designed in order to imitate the motion of bird wing. The virtual prototype of this mechanism is established through ADAMS, then the kinematic simulation analysis is applied to the prototype in order to improve the quality of the flapping wing flight. For the problem of the unsteady aerodynamic of flapping wing flight, by using the method of numerical simulation, the aerodynamic force is analyzed. The wing and tail are designed in the end. All these works are supposed to find the best design scheme and achieve sustainable flapping wing flight. 2. Design and Simulation Analysis of The Flapping -wing Mechanism

UAV Gesture Interaction Design for Volumetric Surveillance

Numbers of UAV such as four or six rotor aircraft has been dramatically increased over recent years. And the volumetric surveillance based on UAV has been found to be extremely useful in haze visibility detection. however, owing to biunique flight control mode, the cost is higher and flexibility is limited, therefore, an effective human-UAV interaction is needed urgently, so that the UAV array could be controlled naturally by human hand. In this paper, a novel UAV gesture interaction scheme based on Kinect sensor and 2-D camera is presented. In the method, a kind of interaction interface is designed, then the UAV array is controlled in single or double hand. For gesture interaction details, based on the text search method proposed by Shahrouz, a new algorithm called “dummy independently component” is presented. In this approach, the finger movement is classified based on it's coherence, consequently, the number of parameters and database dimension are decreased, and search speed is improved. To verify the feasibility and effectiveness of scheme proposed above, final output is rendered with computer simulation and practical experiment.

低雷诺数旋翼翼型设计及气动仿真

This research focuses on the thin circular arc rotor airfoils at a low Reynolds number.A novel thin circular arc airfoil with a convex structure was designed in consideration of its demand for high aerodynamic performance,high structural strength,lightweighting and easy manufacture.A convex curve on the upper surface of the airfoil was adopted to increase the thickness of airfoil at the partial chord and a stiffener in the airfoil was installed to improve the structural strength of blade span wise.The designed thin circular arc airfoil has the maximum thickness of 4.3%,a circular average thickness of 2.5%,the maximum camber of 5.5% and an average camber of 4.5%.Numerical simulations for computing the aerodynamic performance of the airfoil were performed at the representative Reynoldsnumber between 40,000 and 100,000,and the angle of attack(AOA)from-4°to 12°by using the two dimensional steady and incompressible Navier-Stoke equations.The pressure coefficient distribution line of airfoil surfaces and the velocity vector were acquired.A carbon fiber rotor with a diameter of 40 cm,a mass of 15 g and rotor pitch of 15.7cm was manufactured with the present airfoil,and the experiments on the lift force and the structural strength in a hover state were performed and the results show the performance of the airfoil meets the use requirments.At present,the developed rotor airfoil has been successfully used in a rotor aircraft.

INDI Control with Direct Lift for a Tilt Rotor UAV

The benefits of adding direct lift control capabilities to a high aspect ratio, low wing load, tilt rotor UAV within an Incremental Nonlinear Dynamic Inversion framework are presented in this paper. The primary motivation is the need for some gust alleviation scheme to mitigate the large sensitivity to turbulence of light weight, low wing loaded aircraft, such as small tilt rotor UAVs, designed to operate at low speeds. The highly nonlinear dynamic model of the tilt rotor aircraft was developed using the component buildup method associated with the lifting line theory. The effector redundancy was managed through a control allocation module based on the daisy chaining strategy. Classic aerodynamic effectors are used in forward flight, whereas thrust vectoring is required in hover. During transition phases aerodynamic effectors are preferred over thrust vectoring, which intervenes upon saturation of aerodynamic effectors or when they become ineffective at low speed. Since dynamic inversion exhibits poor performance in turbulence due to its intrinsic aggressive use of controls, direct lift is proposed in this paper for gust alleviation, improving performance and reducing overall control effort. Direct lift has been achieved adopting full span flaperons: symmetric deflection generates lift whereas differential deflection produces roll. Direct lift control has the benefit of providing direct, thus fast control of the vertical degree of freedom, whereas conventional elevators try to minimize vertical speed fluctuations through pitch attitude changes, resulting in considerable lags. Another desirable feature of direct lift control for tilt rotor application is the closer commonality between the forward and hover flight regimes, by providing direct control of the vertical motion in forward flight, as provided by thrust vectoring in hover. A comparison was done between similar control law schemes with and without direct lift. Simulations proved the effectiveness of the approach in improving reference tracking in presence of turbulence and reducing control effort.

Numerical study on flow fields and aerodynamics of tilt rotor aircraft in conversion mode based on embedded grid and actuator model

A method combining rotor actuator disk model and embedded grid technique is presented in this paper, aimed at predicting the flow fields and aerodynamic characteristics of tilt rotor aircraft in conversion mode more efficiently and effectively. In this method, rotor’s influence is considered in terms of the momentum it impacts to the fluid around it; transformation matrixes among different coordinate systems are deduced to extend actuator method’s utility to conversion mode flow fields’ calculation. Meanwhile, an embedded grid system is designed, in which grids generated around fuselage and actuator disk are regarded as background grid and minor grid respectively, and a new method is presented for ‘donor searching’ and ‘hole cutting’ during grid assembling. Based on the above methods, flow fields of tilt rotor aircraft in conversion mode are simulated, with three-dimensional Navier–Stokes equations discretized by a second-order upwind finite-volume scheme and an implicit lower–upper symmetric Gauss–Seidel (LU-SGS) time-stepping scheme. Numerical results demonstrate that the proposed CFD method is very effective in simulating the conversion mode flow fields of tilt rotor aircraft.

Control System Designed for a Four Rotors Unmanned Aerial Vehicle

In order to achieve the autonomous flight control of the quadrotor, an autonomous flight control hardware platform was set up, with a self-assembly aircraft as the body frame. The control system was designed according to the principle of quadrotor. It includes the hardware and code. A flight control model for the four rotor aircraft was established, so as to analyze and optimize the performance. Flight test was down. And the results showed that the quadrotor was able to flight stably and be well controlled.

Self-Scheduled and Robust Control for Tilt Rotor Aircraft

A kind of self-scheduled and robust control algorithm for the conversion mode of tilt rotor aircraft is proposed in this paper. The mathematical model of the aircraft is established by modeling each component and combining. Then the conversion corridor is obtained by trim results. The convex combination of several vertex system combined with two-dimensional interpolation is designed to solve the problem of self-scheduled while nacelle tilting. Last sufficient and necessary conditions for the existence of the state-feedback controller are given and a MATLAB tool is raised to ensure performance of the system.

Non-Linear PID Controller Parameter Optimization of Vertical Take-Off and Landing Stage for Tilt Rotor Aircraft

Proportion, integration and differential gain of nonlinear PID Controller is nonlinear function of controlling error. This paper performed the non-linear PID controller parameter optimization of vertical take-off and landing stage for tilt rotor aircraft using the genetic algorithm. Dual loop control is used. Inner loop is angular velocity loop. Outer loop is angular position loop. According to the features of stability control of vertical take-off and landing stage of tilt rotor aircraft, system ascend time, steady error, and weighted overshoot are chosen as objective function of optimization. Simulation results show that controller designed by the present method can meet the requirement of control.

Control Law and Simulation Analysis of Vertical Take-Off and Landing Stage of Tilt Rotor Aircraft

This paper utilized the genetic algorithm to optimize the PID controller of vertical take-off and landing stage of tilt rotor aircraft. According to the features of stability control of vertical take-off and landing stage of tilt rotor aircraft, system ascend time, steady error, and weighted overshoot are chosen as objective function of optimization. Simulation results show that PID controller designed by the genetic algorithm possess the excellent flexibility, adaptability and can produce the better control effect.

Design and Construction of a Quad Tilt-Rotor UAV using Servo Motor

Unmanned aerial vehicles (UAVs) that have been recently commercialized can largely be divided into fixed-wing aircraft and rotor aircraft by their styles and flight characteristics. Although the fixed-wing aircraft represents higher power efficiency, higher speed, longer flight distance and larger loading weight than the rotor aircraft, they have a disadvantage of requiring a space for take-off and landing. On the other hand, the rotor aircraft can implement vertical take-off and landing (VTOL) and represents various flight modes (hovering, steep bank turns and low-speed flights). But they require both precision take-off control and attitude control. In this study, we used a quad-tilt rotor UAV to combine advantages in both the fixed-wing aircraft and the rotor aircraft. The quad-tilt rotor (QTR) system was designed and constructed by adding a tilt device with a servo motor to a general quad-rotor vehicle.

Study of Mechanical Behaviour of Stir Cast Aluminium Based Composite Reinforced with Mechanically Ball Milled TiB<sub>2 </sub>Nano Particles

Metal matrix composites possess some glamorous properties like light weight, low density ,high strength-to-density ratio, formable to complex shape, lower manufacturing cost and are used more in commercial, industrial, marine, naval based industrial and are extensively used in automobiles and aerospace like empennage, wings, fuselage in fighter aircraft, bomber, transport, general aviation, rotary aircraft etc. Many researches are done on micro structural metals matrix composites and they result shows that composite of micro structural having good mechanical properties. Instead of using micro structural nanoparticles are used for better mechanical properties and better applications in aeronautical field. The present study is an attempt to prepare and analysis of mechanical properties of Aluminium 6061 reinforcement with TiB2 nanoparticles using liquid metallurgy. By the use of ball milling process the TiB2 micro particles are converted in to nanoparticles and reinforced with Aluminium 6061 in stir casting process. The addition level of reinforcement is being varied from 0-15wt% in step of 4 wt%.Test carried out on the fabricated composite included scanning electron microscopy, XRD, EDAX analysis, and Thermal analysis.

Study of a Four Rotor Aircraft Modeling

In order to design the four rotor aircraft attitude control system, take the hover state or low speed flight state as a benchmark, firstly, divide the aircraft model into linear motion model and the angular motion model and model it separately, the nonlinear mathematical model of aircraft can be obtained. And then use the small disturbance linearization principle to linear mathematical model for a simplified model. After substituting into the previous experimental data, the mathematical model which controller design needs is got.