Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> This paper describes a control strategy to stabilize the position of a vertical takeoff and landing (VTOL) unmanned aerial vehicle (UAV) in wind gusts. The proposed approach takes advantage of the cascade structure of the system to design a hierarchical controller. The idea is to separate the controller in a high level controller devoted to position control and a low level controller devoted to stabilization and attitude control. Both controllers are designed by means of backstepping techniques that allow the stabilization of the vehicle's position while on-line estimation of the unknown aerodynamic forces. The global stability of the connected system is proven, and simulations as well as experimental results are presented <s> BIB001 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> This paper presents an experimental study on the development of a cyclogyro-based flying robot with a new variable angle of attack mechanism. A cyclogyro is a flying machine supported in the air by power-driven rotors that rotate about a horizontal axis, like the paddle-wheels of a steamboat. Machines of this type have been designed by some companies but there has been no record of any successful flights. Our design starts with a new variable angle of attack mechanism with an eccentric (rotational) point in addition to a rotational point connecting to a motor. The main feature of the mechanism with the eccentric rotational point is the ability to change attack of angles in accordance with the wing positions (as determined by the rotational angles of the cyclogyro) without actuators. The design parameters (wing span, the number of wings, and eccentric distance) of the flying robot are determined through a series of experiments. Experimental results show that the cyclogyro-based flying robot with the new variable angle of attack mechanism is capable of generating sufficient lift force for flying. <s> BIB002 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> We present in this paper a novel indoor blimp that is propelled by a propulsion technology that uses no moving mechanical parts and thus is noiseless and vibration free. In our prior work reported at IEEE/ASME AIM 2007, we demonstrated several prototype propulsive units (with asymmetric capacitor configurations) that lift themselves into air. Using these basic propulsive units (“Ionic Flyers”), we have recently developed an indoor flying blimp that has a propulsion system with no moving mechanical parts and thus generates no noise or vibration - the Ionic Propulsion Blimp. The key to successfully create this novel indoor flying system is the development of a power generation system that includes an 11.1V battery which is capable of generating ∼20kV DC voltage continuously over time for a load in the MΩ range. The architecture of this ionic power system will be presented. A detailed parametric analysis and an optimal design methodology of the Ionic Flyer are also discussed. Initial experimental results of the Ionic Propulsion Blimp are also summarized in this paper. <s> BIB003 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> 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. <s> BIB004 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> The kite mechanics including some basic aerodynamics is reviewed in order to set up a framework for the development of robotic kite systems. Some historical background is provided together with a brief review of kite applications, which have been numerous and diverse. Robotizing the kite is expected to enhance its capabilities and revive scientific kiting. Towards that direction a methodology for controlling the angular elevation (and the altitude) of a single-line kite by actively adjusting the length of its bridle strings is proposed together with the required implementation hardware. Preliminary simulations and proof-of-concept field testing using a box kite were carried out. <s> BIB005 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> This paper demonstrates the feasibility of accomplishing real-world inspection tasks beyond visual range with an autonomous helicopter using simple but effective methods. We propose a LIDAR-based perception and guidance system that enables a helicopter to perform obstacle detection and avoidance, terrain following, and close-range inspection. The system has been implemented on board the CSIRO unmanned helicopter and flight tested in a number of different mission scenarios in unknown environments. We have successfully completed 37 missions and recorded more than 14 hours of autonomous flight time. Missions beyond visual range were executed without a backup pilot. The system has achieved a high success rate and has proven to be dependable. <s> BIB006 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> In recent years, there has been an increasing interest in autonomous navigation for lightweight flying robots in indoor environments. Miniature airships, which are an instance of such robots, are especially challenging since they behave nonlinearly, typically are under-actuated, and also are subject to drift. These aspects, paired with their high-dimensional state space, demand efficient planning and control techniques. In this paper, we present a highly effective approach to autonomous navigation of miniature blimps in mapped environments which applies a multi-stage algorithm to accomplish strongly goal-directed tree-based kinodynamic planning. It performs path-guided sampling and optimally selects actions leading the robot towards sampled subgoals. Based on this, our approach can quickly provide a partial trajectory, which is extended and refined in the consecutive planning steps. The navigation system has been implemented and is able to reliably operate a robotic blimp in a real-world setting. Further experiments demonstrate that our approach outperforms a standard tree planner. <s> BIB007 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> In this article we present a mathematical model of a spincopter - an inherently stable and easy to control unmanned aerial vehicle (UAV). Although the devised model represents only the first approximation of spincopter's physics, it captures basic phenomena that are sufficient for derivation and testing of a simple control algorithm. Results obtained by simulations in Simulink®, presented herein, demonstrate efficient performance of the proposed simple controller structure. Further tests, including investigation of complex aerodynamics effects and hardware-specified limitations, have been done using X-Plane® software package. Finally, the proposed controller has been tested experimentally. Both, X-Plane® and experimental results confirmed the outcome from Simulink®. <s> BIB008 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> Autonomous navigation in obstacle-dense indoor environments is very challenging for flying robots due to the high risk of collisions, which may lead to mechanical damage of the platform and eventual failure of the mission. While conventional approaches in autonomous navigation favor obstacle avoidance strategies, recent work showed that collision-robust flying robots could hit obstacles without breaking and even self-recover after a crash to the ground. This approach is particularly interesting for autonomous navigation in complex environments where collisions are unavoidable, or for reducing the sensing and control complexity involved in obstacle avoidance. This paper aims at showing that collision-robust platforms can go a step further and exploit contacts with the environment to achieve useful navigation tasks based on the sense of touch. This approach is typically useful when weight restrictions prevent the use of heavier sensors, or as a low-level detection mechanism supplementing other sensing modalities. In this paper, a solution based on force and inertial sensors used to detect obstacles all around the robot is presented. Eight miniature force sensors, weighting 0.9g each, are integrated in the structure of a collision-robust flying platform without affecting its robustness. A proof-of-concept experiment demonstrates the use of contact sensing for exploring autonomously a room in 3D, showing significant advantages compared to a previous strategy. To our knowledge this is the first fully autonomous flying robot using touch sensors as only exteroceptive sensors. <s> BIB009 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> This paper presents a cooperative system architecture that extends the flight duration of multiple gliding fixed-wing Unmanned Aerial Vehicles (UAVs) for long endurance missions. The missions are defined by a set of Points of Interest (PoI) and UAVs should pass through them. A module to detect and identify thermals is implemented to exploit their energy and extend the flight duration, known as static soaring. A collision-free trajectory planner based on the RRT* (Optimal Rapidly-exploring Random Trees) planning algorithm is implemented. The proposed system allows applications in real time because of its low computational needs. Simulations and experiments carried out in the airfield of La Cartuja (Seville, Spain) show the performance and advantages of the proposed system. <s> BIB010 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> This study describes the design and implementation of several bioinspired algorithms for providing guidance to an ultra-lightweight micro-aerial vehicle (MAV) using a 2.6 g omnidirectional vision sensor. Using this visual guidance system we demonstrate autonomous speed control, centring, and heading stabilisation on board a 30 g MAV flying in a corridorlike environment. In addition to the computation of wide-field optic flow, the comparatively high-resolution omnidirectional imagery provided by this sensor also offers the potential for image-based algorithms such as landmark recognition to be implemented in the future. <s> BIB011 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> We describe the design and implementation of a modular vertical take-off and landing vehicle, which can be assembled and flown in an unlimited number of arbitrary configurations. This vehicle is intended to be used as a testbed for evaluating distributed estimation and control algorithms. We present the custom hardware, dynamics model, method of state estimation, and a parameterized control strategy capable of controlling any flight-feasible configuration of the vehicle. In terms of the control strategy, we describe a method for optimizing its parameters in order to achieve the best possible performance subject to the system's physical constraints. We then show a straightforward method of mapping the configuration space of our vehicle to the control parameter space. Experimental results are included, demonstrating flight for a variety of configurations both indoors and outdoors. <s> BIB012 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> This paper presents the design, development, and verification of a miniature integrated jumping and gliding robot, the MultiMo-Bat, which is inspired by the locomotion strategy of vampire bats. This 115.6 g robot exhibits high jumping and gliding performance, reaching heights of over 3 m, to overcome obstacles in the environment. The MultiMo-Bat was developed by a novel integrated design strategy that combines jumping and gliding locomotion modes and minimizes the necessary actuation and structural components by sharing a significant portion of the components required for each mode; nearly 70% of the total robot mass is utilized by both modes. This results in overall low mass, low volume, and high co-operation between the modes which allows for the preservation of over 80% of the performance of the independent jumping locomotion mode when combined. This not only allows for two high-performance locomotion modes, but also for all of the necessary actuation components to be on board. Key considerations and components of the design are discussed in the context of the integrated design approach. A prototype of the system is constructed and experimentally tested in various configurations to elucidate the overall system and integration performance. Finally, metrics are developed to begin to quantify the level and performance of the integrated approach as well as allow it to be compared to other mechanical and biological systems. This type of jumping and gliding robot can be used to explore, inspect, and monitor unstructured environments for security and environment monitoring applications. <s> BIB013 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> In this work, we present a flying saucer, a kind of unmanned aerial vehicle(UAV), lifted based on Coandă effect. Coandă effect is an interesting fluid dynamic phenomenon that the interaction between the flow and curved surfaces produce attraction, which results in the lifting of the object. The flying saucer adopting Coandă effect is easy to hover while keeping its posture stable, and vertical take-off and landing(VTOL) is possible. Its design procedures via optimization and manufacturing procedures are explained in details, and the preliminary tests in the indoor and outdoor are successfully demonstrated. <s> BIB014 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> We present the control design, system integration, and free flight evaluation of a novel 227 g swashplateless coaxial helicopter. This micro aerial vehicle (MAV) achieves authority over roll, pitch, and yaw orientation as well as maneuvering thrust using only two propellers directly affixed to two motors. No additional aerodynamic control surfaces or actuators are introduced. Instead, cyclic control is obtained through the underactuated dynamic response of the main rotor itself to a modulated drive torque. Comparisons are drawn to conventional four-motor quadrotors and four-actuator fixed pitch coaxial helicopters in terms of mechanical complexity and actuator mass fraction. Trim power consumption in hover is reported across a range of symmetric and asymmetric loading states. Closed loop trajectory tracking maneuvers are demonstrated in a motion capture environment. <s> BIB015 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> Aerial cargo delivery, also known as airdrop, systems are heavily affected by atmospheric wind conditions. Guided airdrop systems typically employ onboard wind velocity estimation methods to predict the wind in real time as the systems descend, but these methods provide no foresight of the winds near the ground. Unexpected ground winds can result in large errors in landing location, and they can even lead to damage or complete loss of the cargo if the system impacts the ground while traveling downwind. This paper reports on a ground-based mechatronic system consisting of a cup and vane anemometer coupled to a guided airdrop system through a wireless transceiver. The guidance logic running on the airdrop system's onboard autopilot is modified to integrate the anemometer measurements at ground level near the intended landing zone with onboard wind estimates to provide an improved, real-time estimate of the wind profile. The concept was first developed in the framework of a rigorous simulation model and then validated in the flight test. Both simulation and subsequent flight tests with the prototype system demonstrate reductions in the landing position error by more than 30% as well as a complete elimination of potentially dangerous downwind landings. <s> BIB016 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> Online pose estimation and mapping in unknown environments is essential for most mobile robots. Especially autonomous unmanned aerial vehicles require good pose estimates at comparably high frequencies. In this paper, we propose an effective system for online pose and simultaneous map estimation designed for light-weight UAVs. Our system consists of two components: (1) real-time pose estimation combining RTK-GPS and IMU at 100 Hz and (2) an effective SLAM solution running at 10 Hz using image data from an omnidirectional multi-fisheye-camera system. The SLAM procedure combines spatial resection computed based on the map that is incrementally refined through bundle adjustment and combines the image data with raw GPS observations and IMU data on keyframes. The overall system yields a real-time, georeferenced pose at 100 Hz in GPS-friendly situations. Additionally, we obtain a precise pose and feature map at 10 Hz even in cases where the GPS is not observable or underconstrained. Our system has been implemented and thoroughly tested on a 5 kg copter and yields accurate and reliable pose estimation at high frequencies. We compare the point cloud obtained by our method with a model generated from georeferenced terrestrial laser scanner. <s> BIB017 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> In this paper we present the design and control of a novel six degrees-of-freedom aerial vehicle. Based on a static force and torque analysis for generic actuator configurations, we derive an eight-rotor configuration that maximizes the vehicle's agility in any direction. The proposed vehicle design possesses full force and torque authority in all three dimensions. A control strategy that allows for exploiting the vehicle's decoupled translational and rotational dynamics is introduced. A prototype of the proposed vehicle design is built using reversible motor-propeller actuators and capable of flying at any orientation. Preliminary experimental results demonstrate the feasibility of the novel design and the capabilities of the vehicle. <s> BIB018 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> This paper is devoted to the performance optimization of an aerial manipulation system composed of a Flettner-helicopter and 7 DoF manipulator. With experiments we demonstrate that the time delays in signal propagation between perception and actuation modules play an important role for the overall performance of an aerial manipulator system using visual servoing. We present an approach for estimation of the perception-action time delay and its active compensation based on the predicted motion of the manipulator end-effector. <s> BIB019 </s> Recent Developments in Aerial Robotics: A Survey and Prototypes Overview <s> F. Octocopter, Glider, Blimp, and Ionic Flyer UAVs <s> This paper presents the “monospinner”: a mechanically simple flying vehicle with only one moving part. The vehicle is shown to be controllable in three translational degrees of freedom and two rotational degrees of freedom. The vehicle has a single scalar control input, the thrust magnitude, and is controlled by a cascaded control strategy with an inner attitude controller and an outer position controller. The vehicle design is chosen based on two robustness metrics: the ability to maintain hover under perturbations and the probability of input saturation based on a stochastic model. The resulting mechanical and control designs are experimentally demonstrated, where it is also shown that the vehicle is sufficiently robust to achieve hover after being thrown into the air. <s> BIB020
An octocopter (Fig. 12 (a)-(b) ) BIB017 , BIB018 is a UAV with eight rotors. Schneider et al. BIB017 demonstrate an octocopter with a multiple fisheye-camera system that can perform a simultaneous localization and mapping (SLAM) function ( Fig. 12 (a) ). Different from a conventional octocopter, Brescianini and D'Andrea BIB018 build a octocopter that has eight rotors facing to eight different direction in the 3D space ( Fig. 12 (b) ). This unique configuration allows the UAV to have 6 DoF and to hover stably at any attitude. More importantly, the octocopter is able to control its force in the 3D space and is useful for applications such as aerial manipulation. (Fig. (a)-(c) ) BIB006 - BIB019 , coaxial helicopters (Fig. (d)-(f) ) BIB009 , BIB015 , BIB011 , and ducted-fan UAV (Fig. (g) ) BIB001 appear in the reviewed papers. See text for details. Fig. 12 : Prototypes of octocopters (Fig. (a)-(b) ) BIB017 , BIB018 , multirotor (Fig. (c) ) BIB012 , gliders (Fig. (d)-(e) ) BIB013 , BIB010 , blimp (Fig. (f) ) BIB007 , and Ionic Flyer (Fig. (g) ) BIB003 appear in the reviewed papers. See text for details. A multirotor is a UAV with more than one rotor and has simple rotors configuration for flight control. Oung and D'Andrea BIB012 design a modular multirotor system, where each rotor aircraft has a hexagonal shape and can be assembled into a multirotor aircraft with different configuration. With a distributed state estimation algorithm and a parameterized control strategy, the multirotor is able to fly in any flightfeasible configuration both indoors and outdoors (Fig. 12 (c) ). A glider (Fig. 12 (d) -(e)) BIB013 , BIB010 is a UAV that uses its wings and aerodynamics to glide in the air. Glider normally has a outlook like a fixed-wing UAV but does not rely on an active propulsion system during gliding performance. For instance, Cobano et al. BIB010 demonstrate multiple gliders that can glide cooperatively in the sky (Fig. 12 (d) ). To glide for a long time in the sky without active propulsion control, the gliders detect thermal currents and exploit their energy to soar and continue to glide in the air. Inspired by a vampire bat, Woodward and Sitti BIB013 build a different type of glider UAV, where their UAV can jump from the ground and then uses its wings to glide in the air (Fig. 12 (e) ). A blimp, also known as a non-rigid airship, is a lighterthan-air UAV that relies on helium gas inside an envelope to generate lifting force. Different from a Montgolfière or hot air balloon, a blimp keeps its envelope shape with the internal pressure of helium gas and has actuation units for motion control. By using a motion capture system, Müller and Burgard BIB007 present an autonomous blimp that can navigate in an indoor environment with an online motion planning method (Fig. 12 (f) ). Poon et al. BIB003 aim to design a UAV that is noiseless and vibration-free by using ionic propulsion, where they call their UAV Inoic Flyer (Fig. 12 (g) ). Instead of using rotors, they create a propulsion unit that has no moving mechanic parts and relies on high electrical voltage to create thrust by accelerating ions. G. Cyclocopter, Spincopter, Coandǎ, Parafoil, and Kite UAVs A cyclocopter ( Fig. 13 (a)-(b) ) BIB002 , BIB004 is a UAV that flies by rotating a cyclogyro wing with several wings positioned around the edge of a cylindrical structure. Generally, the wings' angles of attack are adjusted collectively by a servo motor to generate required forces. Tanaka et al. BIB002 built a cyclocopter that can the angles of attack using a novel eccentric point mechanism without additional actuators ( Fig. 13 (a) ). Hara et al. BIB004 developed a cyclocopter based on a pantograph structure, where diameters of the wings can be expanded or contracted (with reference to the rotational axis) for flight control (Fig. 13 (b) ). A spincopter (Fig. 13 (c)-(d) ) BIB008 , BIB020 is a UAV that spins itself during flight. Orsag et al. BIB008 designed a spincopter that can spin the central wings (and the whole aircraft) using two small motors mounted at the edge of the virtual ring of the UAV (Fig. 13 (c) ). The motors adjust their output thrust symmetrically/asymmetrically for vertical/horizontal motion control. By using a asymmetrical design and cascaded control strategy, Zhang et al. BIB020 demonstrate a spincopter that has three translational DoF and two rotational DoF with only one rotor ( Fig. 13 (d) ). A Coandǎ UAV is an aircraft that produces lifting force by utilizing the Coandǎ effect. Specifically, the Coandǎ effect is caused by the tendency of a jet of fluid to follow an adjacent surface and to attract the surrounding fluid. Thanks to the Bernoulli principle, in which pressure is low when speed is high, a Coandǎ UAV can generate enough lifting force to hover in the air when the Coandǎ effect is strong enough. Han et al. BIB014 developed a Coandǎ UAV in a flying saucer shape ( Fig. 13 (e) ). By attaching additional servo motors onto the UAV for flap control, their Coandǎ UAV is able to perform VTOL and horizontal movements in the air. Parafoil UAVs (Fig. 13 (f) ) BIB016 and kite UAVs ( Fig. 13 (g) ) BIB005 resemble the shapes and flying principles of a parafoil or kite. For an aerial cargo delivery application, Cacan et al. BIB016 improved the landing accuracy of an autonomous parafoil UAV with the assistance of a ground-based wind measurement system ( Fig. 13 (f) ) while Christoforou develop a robotic kite UAV that can surf automatically in the air (Fig. 13 (g) ) BIB005 .