仿鸟扑翼飞行器姿态镇定研究

针对仿鸟扑翼飞行器的欠驱动特性,提出了一种简化其飞行控制问题并实现其局部渐近稳定的控制方法．建立并分析了仿鸟扑翼飞行器的动力学和运动学模型,证明其控制问题等价于升力、推力独立可控情况下的姿态控制问题．进一步分析的结果表明,仿鸟扑翼飞行器的升力、推力都是独立可控的,其姿态控制为耦合输入下刚体的姿态控制问题．通过设计光滑时变反馈控制律实现姿态控制的局部渐近稳定,从而解决扑翼飞行器的飞行控制问题．     

Development of a Flying Robot With a Pantograph-Based Variable Wing Mechanism

We develop a flying robot with a new pantograph-based variable wing mechanism for horizontal-axis rotorcrafts (cyclogyro rotorcrafts). A key feature of the new mechanism is to have a unique trajectory of variable wings that not only change angles of attack but also expand and contract according to wing positions. As a first step, this paper focuses on demonstrating the possibility of the flying robot with this mechanism. After addressing the pantograph-based variable wing mechanism and its features, a simulation model of this mechanism is constructed. Next, we present some comparison results (between the simulation model and experimental data) for a prototype body with the proposed pantograph-based variable wing mechanism. Both simulation and experimental results show that the flying robot with this new mechanism can generate enough lift forces to keep itself in the air. Furthermore, we construct a more precise simulation model by considering rotational motion of each wing. As a result of optimizing design parameters using the precise simulation model, flight performance experimental results demonstrate that the robot with the optimal design parameters can generate not only enough lift forces but a 155 gf payload as well.      

基于高仿生形态布局的仿鸽扑翼飞行机器人系统设计

针对现有扑翼飞行机器人存在的飞行形态与实际鸟类相差较大, 以及翅膀、尾翼布局和俯仰、转向控制方式仿生度较低的问题, 提出一种形态布局与鸽子相仿的扑翼飞行机器人系统设计及实现方案. 通过设计弧面−折翼−后掠翅膀、仿鸟扇形尾翼以及尾翼挨近翅膀后缘布置的布局方式, 使扑翼机器人飞行形态更加接近真实鸟类, 提高扑翼机器人的形态仿生度. 在此基础上, 设计结合下扑角调控无需尾翼大角度上翘的俯仰控制方式, 以及不依赖于尾翼的翅膀收缩转向控制方式, 在提高仿生度的同时保证飞行控制的有效性. 在具体设计过程中, 首先参考鸽子翅膀型式选择不同类型翅膀并进行风洞测试, 确定出下扑角变化时仍能保持较优升推力性能的翅膀设计方案; 其次, 对各种尾翼型式进行分析和比较, 结合鸽子尾翼特点进行仿鸽尾翼及俯仰、转向控制机构设计, 并通过风洞测试验证; 最后, 设计飞控系统并装配整机, 进行外场飞行测试, 验证仿鸽扑翼飞行机器人平台的稳定性和可控性.     

Mechanical principles of dynamic terrestrial self-righting using wings

Terrestrial animals and robots are susceptible to flipping-over during rapid locomotion in complex terrains. However, small robots are less capable of self-righting from an upside-down orientation compared to small animals like insects. Inspired by the winged discoid cockroach, we designed a new robot that opens its wings to self-right by pushing against the ground. We used this robot to systematically test how self-righting performance depends on wing opening magnitude, speed, and asymmetry, and modeled how kinematic and energetic requirements depend on wing shape and body/wing mass distribution. We discovered that the robot self-rights dynamically using kinetic energy to overcome potential energy barriers, that larger and faster symmetric wing opening increases self-righting performance, and that opening wings asymmetrically increases righting probability when wing opening is small. Our results suggested that the discoid cockroach’s winged self-righting is a dynamic maneuver. While the thin, lightweight wings of the discoid cockroach and our robot are energetically sub-optimal for self-righting compared to tall, heavy ones, their ability to open wings saves them substantial energy compared to if they had static shells. Analogous to biological exaptations, our study provided a proof-of-concept for terrestrial robots to use existing morphology in novel ways to overcome new locomotor challenges.     

一款模拟昆虫飞行方式的微小型扑翼机

设计了一款模拟昆虫飞行方式的微小型扑翼机,仿照蜻蜓的两翼,直升机式尾翼,以STC15F2K60S2为主控芯片,应用主流无线模块来完成实现遥控仿生扑翼机的设计与制作,经过实际测试能够满足飞行要求.     

基于线驱转向的仿蝴蝶扑翼飞行机器人系统设计与控制

作为一种新型飞行机器人, 仿蝴蝶扑翼飞行机器人模仿自然界蝴蝶的生物结构和飞行方式, 能够有效地融 入并适应复杂环境, 在军民融合领域具有广阔的应用前景. 目前针对仿蝴蝶扑翼飞行机器人的研究大多停留在对生 物蝴蝶飞行机理的研究, 鲜有能够实现自由可控飞行的机器人系统. 本文设计了一款基于线驱转向的仿蝴蝶扑翼飞 行机器人, 名为USTButterfly-S, 其翼展50 cm, 重50 g, 可实现长达5分钟的自由可控飞行. 首先结合生物蝴蝶翅膀的 扑动特征, 设计了双曲柄双摇杆对称扑翼驱动机构. 然后模仿凤蝶的翅翼形状, 设计了仿蝴蝶翼型. 对翅膀的几何学 分析表明, USTButterfly-S的翅膀与凤蝶具有较好的形态相似性. 接着针对仿蝴蝶扑翼飞行机器人的转向控制问题, 首次采用线驱动机构拉动翅膀调节翅翼面积, 进而实现了USTButterfly-S的无尾航向控制. 最后集成自主设计的飞 控系统, USTButterfly-S能够实现室内盘旋飞行并进行实时航拍. 在实际飞行实验中, USTButterfly-S展现出类似生 物蝴蝶的飞行特征.     

Modeling and Simulation of the HADA Reconfigurable UAV

The “Helicopter ADaptive Aircraft” (HADA) is a reconfigurable UAV that performs both as a helicopter for take-off, landing and hovering flight, but that “morphs” in flight to a conventional fixed wing configuration for cruise flight, unfolding the wings that are beneath the fuselage and transferring power from the main rotor to a pusher propeller. This paper presents the dynamic model of the behaviour of the HADA in the transition phases. The model takes into account the aerodynamic effects and variable mass and inertia characteristics of variable sweeping wings which are present in the HADA design, incorporating wind tunnel data. Simulations of the wing deployment process of the HADA are also presented.     

Modeling Synchronous Muscle Function in Insect Flight: a Bio-Inspired Approach to Force Control in Flapping-Wing MAVs

Micro-aerial vehicles (MAV) and their promising applications—such as undetected surveillance or exploration of environments with little space for land-based maneuvers—are a well-known topic in the field of aerial robotics. Inspired by high maneuverability and agile flight of insects, over the past two decades a significant amount of effort has been dedicated to research on flapping-wing MAVs, most of which aim to address unique challenges in morphological construction, force production, and control strategy. Although remarkable solutions have been found for sufficient lift generation, effective methods for motion control still remain an open problem. The focus of this paper is to investigate general flight control mechanisms that are potentially used by real insects, thereby providing inspirations for flapping-wing MAV control. Through modeling the insect flight muscles, we show that stiffness and set point of the wing’s joint can be respectively tuned to regulate the wing’s lift and thrust forces. Therefore, employing a suitable controller with variable impedance actuators at each wing joint is a prospective approach to agile flight control of insect-inspired MAVs. The results of simulated flight experiments with one such controller are provided and support our claim.     

Modeling and emergence of flapping flight of butterfly based on experimental measurements

The objective of this paper is to clarify the principle of stabilization in flapping-of-wing flight of a butterfly, which is a rhythmic and cyclic motion. For this purpose, a dynamics model of a butterfly is derived by Lagrange’s method, where the butterfly is considered as a rigid multi-body system. For the aerodynamic forces, a panel method is applied. Validity of the mathematical models is shown by an agreement of the numerical result with the measured data. Then, periodic orbits of flapping-of-wing flights are searched in order to fly the butterfly models. Almost periodic orbits are obtained, but the model in the searched flapping-of-wing flight is unstable. This research, then, studies how the wake-induced flow and the flexibly torsional wing’s effect on the flight stability. Numerical simulations demonstrate that both the wake-induced flow and the flexible torsion reduces the flight instability. Because the obtained periodic flapping-of-wing flight is unstable, a feedback control system is designed, and a stable flight is realized.     

Virtual Chassis for Snake Robots: Definition and Applications

Abstract

Intuitively representing the motion of a snake robot is difficult. This is in part because the internal shape changes that the robot uses to locomote involve the entire body and no single point on the robot intuitively represents the robot’s pose at all times. To address this issue, we present a method of defining body coordinate frames that departs from the typical convention of rigidly fixing a frame to a link on the robot, and instead define a body frame that is based on the averaged position of all of the robot’s links. This averaged frame serves as a virtual chassis that effectively isolates the internal motion of the robot’s shape changes from the external motion, due to the robot’s interaction with its surroundings. This separation of motion allows much simpler models—such as those derived for wheeled vehicles—to accurately approximate the motion of the robot as it moves through the world. We demonstrate the practical advantages of using the virtual chassis body frame by estimating the pitch and roll of a snake robot undergoing dynamic motion by fusing readings from its internal encoders, gyros, and accelerometers with an extended Kalman filter.     

Robot motion control in zero-gravity conditions

We have considered the motion control of a space robot composed of a body and a telescopic manipulator arm. The robot is in the state of free passive flight. The vector of the number of movements and the kinetic moment of the robot relative to the center of mass are zero. The manipulator arm motion causes a corresponding motion of the robot body (change in the position of the center of mass of the body and its rotation). Unlike earlier results, we have revealed that the robot grip can be shifted from an arbitrary initial position to an arbitrary final position inside the operating area and, in addition, the required (most convenient for operations) angle between the manipulator arm and the robot body in the final position can be obtained.     

A Bio-Inspired Flapping-Wing Robot With Cambered Wings and Its Application in Autonomous Airdrop

Flapping-wing flight, as the distinctive flight method retained by natural flying creatures, contains profound aerodynamic principles and brings great inspirations and encouragements to drone developers. Though some ingenious flapping-wing robots have been designed during the past two decades, development and application of autonomous flapping-wing robots are less successful and still require further research. Here, we report the development of a servo-driven bird-like flapping-wing robot named USTBird-I and its application in autonomous airdrop. Inspired by birds, a camber structure and a dihedral angle adjustment mechanism are introduced into the airfoil design and motion control of the wings, respectively. Computational fluid dynamics simulations and actual flight tests show that this bionic design can significantly improve the gliding performance of the robot, which is beneficial to the execution of the airdrop mission. Finally, a vision-based airdrop experiment has been successfully implemented on USTBird-I, which is the first demonstration of a bird-like flapping-wing robot conducting an outdoor airdrop mission.      

Study on the structural optimization of a flapping wing micro air vehicle

The development of flapping wing micro air vehicles (MAVs) has yielded remarkable progress over the last decades. Achieving high component stiffness is often in conflict with low weight requirement, which is highly desirable for longer flight time and higher payload. Moreover, vibration originated predominantly from the wings, gears and frames excitations, may compromise the flapping wing MAV’s stability and fatigue life. In order to improve the vehicle’s efficiency and performance, optimization of these various parameters is necessary. In this work, we present the structural optimization of a flapping wing micro air vehicle. We focus particularly on the gearbox optimization using Simulia Tosca Structure in Abaqus, which is a robust tool for designing lightweight, rigid and durable components. Various numerical experiments have been conducted towards optimizing the components’ topology, aimed at increasing the stiffness and reducing weight. The finding and results provide a better understanding of the optimal design topology for a spur gear among other structural components used in MAVs.     

仿鸟类扑翼飞行器研究进展

仿生扑翼飞行器有着优异的气动性能和灵活的飞行能力,在军民领域均有广泛的应用前景,学者们在原理样机研制、扑翼气动机理、驱动机构、飞行控制等多领域取得了一系列重要进展.本文从总体设计方法、驱动机构设计与优化、气动机理等方面综述了仿鸟类扑翼飞行器技术的发展历程与研究进展.首先,从扑翼总体设计方法入手,总结了仿鸟类扑翼飞行器仿生构型,归纳了总体设计参数估算方法;其次,综述了多种构型曲柄连杆机构在扑翼驱动中的应用与优缺点;接着总结了扑翼气动机理研究的实验方法与数值计算方法,分析了不同扑翼气动算法针对不同应用场景在计算成本和准确度方面的优劣情况;最后,对仿鸟类扑翼飞行器系统设计研究现状进行总结,针对原理样机研制过程提出展望.     

基于优化配平的机翼故障飞机飞行性能分析

分析飞机机翼故障对飞行性能的影响,对飞机故障后能够安全着陆或返航有着重要意义,飞机的机翼作为产生力和力矩的主要部件对飞行性能起着重要的作用。提出一种基于单纯形优化的机翼故障飞机飞行性能分析方法,建立机翼故障参数模型,根据飞机爬升转弯飞行条件进行优化配平计算,得到在不同状态下不同机翼故障的配平数据库,分析了故障后飞机的飞行性能。仿真结果表明所提算法的有效性。     

Reachability Analysis of Landing Sites for Forced Landing of a UAS

This paper details a method to ascertain the reachability of known emergency landing sites for any fixed wing aircraft in a forced landing situation. With a knowledge of the aircraft’s state and parameters, as well as a known wind profile, the area of maximum glide range can be calculated using aircraft equations of motion for gliding flight. A landing descent circuit technique used by human pilots carrying out forced landings called high key low key is employed to account for the extra glide distance required for an approach and landing. By combining maximum glide range analysis with the descent circuit, all the reachable landing sites can be determined. X-Plane flight simulator is used to demonstrate and validate the techniques presented.     

Dissection of a Flexible Wing's Performance for Insect-Inspired Flapping-Wing Micro Air Vehicles

We present a computational study on the aerodynamic performance of flexible wings aiming to facilitate the design of insect-inspired flapping-wing micro air vehicles (FMAVs). First, we propose using a two-dimensional mechanical model for a flapping wing to help understand the mechanism underlying its unsteady deformation when exposed to aerodynamic and inertia forces. This is followed by comparative analyses of both flexible wings and fixed wings in flight. In particular, a 'swaying propulsion' mechanism is proposed to mimic the flapping of the winged insects, and a new concept of 'initial torsion angle' is introduced to provide an equivalent means to account for the asymmetry of the torsional stiffness of the thorax muscle during upstroke and downstroke flapping. Subsequently, the aerodynamic forces and power requirements for a bumblebee's wings under various flight conditions are systematically examined. Our results indicate that flexibility of the wings largely contributes to the high lifts and that gliding forces play a significant role in improving flight performance, suggesting that optimal design of the structure and flapping motions of wings could achieve improved efficiency in FMAVs. These studies promote a brand new design concept for future insect-inspired FMAVs.     

Towards efficient flight: insights on proper morphing-wing modulation in a bat-like robot

In this article, we address the question of how the flight efficiency of Micro Aerial Vehicles with variable wing geometry can be inspired by the biomechanics of bats. We use a bat-like drone with highly articulated wings using shape memory alloys (SMA) as artificial muscle-like actuators. The possibility of actively changing the wing shape by controlling the SMA actuators, let us study the effects of different wing modulation patterns on lift generation, drag reduction, and the energy cost of a wingbeat cycle. To this purpose, we present an energy-model for estimating the energy cost required by the wings during a wingbeat cycle, using experimental aerodynamic and inertial force data as inputs to the energy-model. Results allowed us determining that faster contraction of the wings during the upstroke, and slower extension during the downstroke enables to reduce the energy cost of flapping in our prototype.     

Efficient autonomous global localization for service robots using dual laser scanners and rotational motion

This study presents an alternative global localization scheme that uses dual laser scanners and the pure rotational motion of a mobile robot. The proposed method extracts the initial state of the robot’s surroundings to select robot pose candidates, and determines the sample distribution based on the given area map. Localization success is determined by calculating the similarity of the robot’s sensor state compared to that which would be expected at the estimated pose on the given map. In both simulations and experiments, the proposed method shows sufficient efficiency and speed to be considered robust to real-world conditions and applications.

     

A linearizing feedback for stabilizing a car-like robot following a curvilinear path

The path following problem for a car-like robot is considered. The control goal is to bring the robot to a pre-assigned curvilinear path and to stabilize its motion along the path. A new canonical change of variables is suggested. It reduces the problem of stabilizing robot’s motion to that of stability of the zero solution of the transformed system in the form that admits feedback linearization. A new control law is synthesized that ensures linearity of the closed-loop system and stabilizes robot’s motion along a given target path if the initial conditions belong to a known region. Comparison of the new control law with two earlier obtained linearizing feedbacks known from the literature demonstrates its unquestionable advantages.