Vision-Based Navigation Frame Mapping and Path Planning for Micro Air Vehicles

Path planning and obstacle avoidance involve planning a feasible path from the initial to goal conflgurations while avoiding obstacles. This paper presents a vision-based three dimensional navigation frame mapping and path planning technique for collision avoidance for Micro Air Vehicles (MAVs) using a forward-looking onboard camera. Using computer vision algorithms, a depth map representing the range and bearing to obstacles is obtained. Based on the depth map, we use the extended Kalman Filter (EKF) to estimate the range and azimuth to obstacles and the height of obstacles and use the joint compatibility branch and bound (JCBB) algorithm to associate the camera measurements with the existing obstacles. A three dimensional map, constructed in cylindrical coordinates, is then created in the navigation frame of the MAV. We employ the Rapidly-Exploring Random Tree (RRT) algorithm to flnd collision-free Dubins paths in the navigation frame. The simulation results show that the proposed technique is successful in solving path planning and multiple obstacles avoidance problems for MAVs.

MAVs (micro air vehicles) with a maximal dimension of 15 cm and nominal flight speeds of around 10 m s−1, operate in a Reynolds number regime of 105 or lower, in which most natural flyers including insects, bats and birds fly. Furthermore, due to their light weight and low flight speed, the MAVs' flight characteristics are substantially affected by environmental factors such as wind gust. Like natural flyers, the wing structures of MAVs are often flexible and tend to deform during flight. Consequently, the aero/fluid and structural dynamics of these flyers are closely linked to each other, making the entire flight vehicle difficult to analyze. We have recently developed a hummingbird-inspired, flapping flexible wing MAV with a weight of 2.4–3.0 g and a wingspan of 10–12 cm. In this study, we carry out an integrated study of the flexible wing aerodynamics of this flapping MAV by combining an in-house computational fluid dynamic (CFD) method and wind tunnel experiments. A CFD model that has a realistic wing planform and can mimic realistic flexible wing kinematics is established, which provides a quantitative prediction of unsteady aerodynamics of the four-winged MAV in terms of vortex and wake structures and their relationship with aerodynamic force generation. Wind tunnel experiments further confirm the effectiveness of the clap and fling mechanism employed in this bio-inspired MAV as well as the importance of the wing flexibility in designing small flapping-wing MAVs.

Micro Air Vehicles (MAVs) have become more attractive for various missions including surveillance or reconnaissance in recent years. MAVs should be capable of maintaining their attitudes through either inherent passive stability or active feedback in order to successfully perform their directives. Stability and Controllability Augmentation Systems (SCASs) are usually employed to enhance the flight performance of conventional aircrafts and Unmanned Aerial Vehicles (UAVs). However, it is no simple task to obtain an accurate numerical model for the flight dynamics of a MAV. An alternative approach for SCASs would be to incorporate reinforcement learning in order to address this numerical complexity. Such implementation has already been successful in other vehicles, such as unmanned ground vehicles (UGVs), because of their bettered stability compared to aerial vehicles. However, in order to train MAVs to learn how to fly, they must first be airborne. Similar to teaching infants how to walk, this paper presents a new method to provide an effective environment where a MAV can learn how to fly. A test setup was constructed to enable magnetic levitation of a MAV embedded with a permanent magnet. This apparatus allows for flexible experimentation: the position and the altitude of the MAV, the constraint forces, and the resulting moments are all adjustable and fixable. This ‘Pseudo Flight Environment’ was demonstrated with a fixed wing MAV model. In order for the model to maintain a constant altitude, a height hold control system was devised and implemented.

Missions envisioned for Micro Air Vehicles (MAVs) such as Intelligence, Surveillance and Reconnaissance (ISR) in urban environments require exceptional agility. These missions typically involve ight through or in close proximity to buildings, tunnels and trees, and require the MAVs to maneuver using sharp dives and climbs along with small-radius turns. The small size of MAVs allows such ight operations within con ned space but the control e ectors must provide su cient maneuverability, while maintaining stability, with only limited sensing capability onboard the platform. To meet these challenges, researchers have long been attracted by the amazing attributes of biological systems, such as those exhibited by birds and insects. Birds can y in dense ocks, executing rapid maneuvers with g-loads far in excess of modern ghter aircrafts, and yet never collide with each other, despite the absence of air tra c controllers. This paper introduces a novel framework for the design and control of a Micro Air Vehicle. The vehicle's conceptual design is based on biologically-inspired principles and emulates a dragon y (Odonata-Anisoptera). The author is borrowing ight mechanism features from the dragon y and merging them with indigenous designs in creating a novel version of a Flapping Wing MAV, called the QV. The QV design incorporates the simplicity of mechanical construction and the complexity of a sophisticated multi-layered Hybrid & Linear / Non-Linear controller to achieve extended ight times and improved agility compared to other Rotary and Flapping Wing MAV designs. The paper talks about the design and control features of the proposed QV design and gives an overview on the developmental e orts been made towards the prototyping of the QV yer. The potential applications for such a high endurance vehicle are numerous, including air-deployable mass surveillance in cluster and swarm formations. The disposability of the vehicle would help in battleeld deployment as well, where such a MAV would be made available to soldiers for proximity sensing and threat level assessment. Other applications would include search and rescue operations and civilian law-enforcement.

We present a novel stereo-based obstacle avoidance system on a vision-guided micro air vehicle (MAV) that is capable of fully autonomous maneuvers in unknown and dynamic environments. All algorithms run exclusively on the vehicle's on-board computer, and at high frequencies that allow the MAV to react quickly to obstacles appearing in its flight trajectory. Our MAV platform is a quadrotor aircraft equipped with an inertial measurement unit and two stereo rigs. An obstacle mapping algorithm processes stereo images, producing a 3D map representation of the environment; at the same time, a dynamic anytime path planner plans a collision-free path to a goal point.

We designed a X-type wing of flapping-wing Micro Air Vehicles (MAV) and doing some aerodynamic force testing by the flapping-wing MAV aerodynamic force testing device which designed by ourselves. In order to study the relationship of aerodynamic force on the flapping-wing models, we do these tests of different flapping-wing models in different angles of attack and flapping frequency. Found that X-wings flapping wing MAV rely mainly on aerodynamic wings folded back when the compressed gas emitted and received; increase the X-wings flapping wing MAV flapping frequency can significantly increase aerodynamic wings; and X-flapping wing MAV Aerodynamic wing root shoot ratio and aspect ratio with the decrease, inversely proportional to the relationship.

Micro Air Vehicles (MAVs) are a new type of aircraft maturing day by day and have reached unprecedented levels of growth recently. Similarly to larger Unmanned Air Vehicles (UAVs), MAVs have enormous potential in applications, both military and civilian, like reconnaissance over battlefields and surveillance of urban areas, data relay, air sampling etc. This article describes the development and selection of a fixed wing MAV with the analysis of simulated results. High wing theory with NACA 4412 aerofoil’s analytical data has been used to practically predict the performance of the MAV. KEY WORDS: Fixed wing; MAV; NACA 4412; Clark Y. DOI: http://dx.doi.org/10.3329/mist.v3i0.8048

Micro Air Vehicles (MAVs) will provide a low-cost, redundant means to perform reconnaissance missions in urban or traditional battlefleld environments. These miniaturized vehicles, however, will have extremely limited capacity for onboard navigation sensors, processors, and inter-vehicle communication. This paper explores the application of emerging consensus algorithms to the problem of distributed MAV coordination and control. Through the use of local information exchange (sensing or communication) links, MAV teams are able to initialize and maintain controlled formation geometries, efiectively forming a sensor web despite the lack of centralized leadership. Results demonstrate the ability of a twenty-MAV team to accurately assemble in a grid formation when all vehicles are initialized in su‐cient proximity to enable a (directed) information exchange topology that spans the MAV network. Without such connectivity, MAV sub-groups form, each of which assembles a smaller version of the original grid formation.

Integrated design of trajectory planning and control for micro air vehicles

Exploration and safe navigation in previously unknown GPS-denied obstructed areas are major challenges for autonomous robots when deployed in subterranean environments. In response, this work establishes an Exploration-Planning framework developed for the real-world deployment of Micro Aerial Vehicles (MAVs) in subterranean exploration missions. The fundamental task for an autonomous MAV to navigate in an unknown area, is to decide where to look while navigating such that the MAV will acquire more information about the surrounding. The work presented in this article focuses around 3D exploration of large-scale caves or multi-branched tunnel like structures, while still prioritizing the Look-Ahead and Move-Forward approach for fast navigation in previously unknown areas. In order to achieve such exploration behaviour, the proposed work utilizes a two-layer navigation approach. The first layer deals with computing traversable frontiers to generate the look ahead poses in the constrained field of view, aligned with the MAV’s heading vector that leads to rapid continuous exploration. The proposed frontier distribution based switching goal selection approach allows the MAV to explore various terrains, while still regulating the MAV’s heading vector. The second layer of the proposed scheme deals with global cost based navigation of the MAV to the potential junction in a multi-branched tunnel system leading to a continuous exploration of partially seen areas. The proposed framework is a combination of a novel frontier goal selection approach, risk-aware expandable grid based path planning, nonlinear model predictive control and artificial potential fields based on local reactive navigation, obstacle avoidance, and control for the autonomous deployment of MAVs in extreme environments.

PurposeThe purpose of this paper is to reformulate the governing equations incorporating major variables and parameters for the design a Micro Air Vehicle (MAV), to meet the desired mission and design requirements.Design/methodology/approachMathematical models for various spherical and cylindrical Coandă MAV configurations were rederived from first principles, and the performance measures were defined. To verify the theoretical prediction to a certain extent, a computational fluid dynamic (CFD) simulation for a Coandă MAV generic models was performed.FindingsThe major variables and parameters of Coandă MAV have been formulated into practical guidelines, which relate the lift (or thrust) produced for certain input variables, particularly the Coandă MAV jet momentum coefficient. The influences of the geometrical parameters are elaborated.Research limitations/implicationsThe present analysis on Coandă jet-configured MAV is focused on the lift generation due to the Coandă jet effect through a meticulous analysis. The effects of viscosity, the Coandă jet thickness, the radius of curvature of the surface and the stability of Coandă jet are not considered and will be the subject of the following work.Practical implicationsThe results obtained can be used for sizing in the preliminary design of Coandă MAVs.Originality/valuePhysical and mathematical models were developed which can describe the physical phenomena of the flow field near the Coandă MAV surfaces influenced by Coandă jet sheets and for obtaining a relationship between relevant variables and parameters to the lift of practical interest.

Recent advances in rotorcraft design, multi-rotor vehicle control, miniaturization of hardware, sensing, and battery technologies have enabled cheap, practical design of micro air vehicles (MAVs) for civilian and hobby applications. In parallel, several applications are being envisioned that bring together networks of MAVs to accomplish large tasks by coordinating with each other. Despite these advancements, and new FAA rules governing their use, it is still very challenging to experiment with multiple networked MAVs. To address this problem, we are engaged in a multi-year effort to develop an open software/hardware platform called the University at Buffalo's Airborne Networking and Communications testbed (UB-ANC1), and an associated emulation environment called the UB-ANC Emulator. Our goal is to design, implement, and test MAV networking applications in simulation, and provide seamless transition to deployment. In our prior work on the UB-ANC Emulator, we considered a simple network simulation in which nodes can communicate with each other if they are within a given range. However, this does not accurately reflect the performance of a MAV network where communication links are subject to interference and packet losses, and protocols at the data link, network, and transport layers have a significant influence on network throughput, latency, and reliability. To overcome this limitation, in this paper, we integrate the open-source discrete-event network simulator ns-3 into the UB-ANC Emulator. We demonstrate through link-level and end-to-end measurements how the UB-ANC Emulator can be used to holistically evaluate MAV networking applications with accurate modeling of mobility, control, wireless channel characteristics, and network protocols using ns-3.

Insect-sized flapping wing micro air vehicles (MAVs) are beginning to take flight but have many technical hurdles to overcome. One of the greatest challenges of MAV design is attaining lightweight microelectronic components of optimal size and shape. In this paper an inductor for incorporation onto a carbon fiber MAV body component is modeled using a multiphysics and lumped parameter approach. A magnetostatic simulation using finite elements provides insight into the magnetic flux density distribution of the inductor. Simulation allows the inductor to be adapted to various shapes and sizes. Lumped values are generated based upon desired values for a MAV inductor. Microelectromechanical systems (MEMS) processes are used to fabricate the inductor directly on a MAV carbon fiber body (e.g. fuselage) component. Fabrication is prototyped on a semiconductor wafer. The inductor (a major contributor to the MAV weight budget) forms the basis for a lightweight, voltage transformer. By transferring the copper conductors to a structural component, the circuitry becomes part of the vehicle structure. This type of MEMS fabrication allows for optimal sizing, weight reduction, a lower part count and much higher levels of integration. These parameters are critical for operational MAV applications.

This thesis studies a controllability approach for general resonant compliant systems. These systems exploit resonance to obtain a specific dynamic response at relatively low actuation power. This type of systems is often lightweight, is scalable and minimizes frictional losses through the use of compliant hinges. Some insect-inspired Flapping Wing Micro Air Vehicle (FWMAV) designs are based on such a resonant compliant system. These designs are carefully tuned such that a particular resonance response of the system corresponds to the desired wing flapping motion. The system’s resonance response depends strongly on its structural properties (i.e., mass, damping, stiffness and their spatial distribution). Resonance response modifications can, thus, be controlled using carefully selected structural property changes. This thesis contributes to the controllability of resonant compliant systems in general and the compliant FWMAV design in particular. Although there is yet no physical, controllable FWMAV design with integrated active components, the current research strongly indicates the applicability of structural property changes to reach controllability of this type of systems. Effective control requires an integrated approach that considers simultaneously the structure, the wings, the kinematics, the methods to induce property changes and the desired controllability.

Water sampling with autonomous aerial vehicles has major applications in water monitoring and chemical accident response. Currently, no robot exists that is capable of both underwater locomotion and flight. This is principally because of the major design tradeoffs for operation in both water and air. A major challenge for such an aerial-aquatic mission is the transition to flight from the water. The use of high power density jet propulsion would allow short, impulsive take-offs by Micro Air Vehicles (MAVs). In this paper, we present a high power water jet propulsion system capable of launching a 70 gram vehicle to speeds of 11m/s in 0.3s, designed to allow waterborne take off for an Aquatic Micro Air Vehicle (AquaMAV). Jumps propelled by the jet are predicted to have a range of over 20m without gliding. Propulsion is driven by a miniaturised 57 bar gas release system, with many other applications in pneumatically actuated robots. We will show the development of a theoretical model to allow designs to be tailored to specific missions, and free flying operation of the jet.