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2012 | Buch

Lighter than Air Robots

Guidance and Control of Autonomous Airships

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Über dieses Buch

An aerial robot is a system capable of sustained flight with no direct human control and able to perform a specific task. A lighter than air robot is an aerial robot that relies on the static lift to balance its own weight. It can also be defined as a lighter than air unmanned aerial vehicle or an unmanned airship with sufficient autonomy. Lighter than air systems are particularly appealing since the energy to keep them airborne is small. They are increasingly considered for various tasks such as monitoring, surveillance, advertising, freight carrier, transportation.

This book familiarizes readers with a hierarchical decoupled planning and control strategy that has been proven efficient through research. It is made up of a hierarchy of modules with well defined functions operating at a variety of rates, linked together from top to bottom. The outer loop, closed periodically, consists of a discrete search that produces a set of waypoints leading to the goal while avoiding obstacles and weighed regions. The second level smoothes this set so that the generated paths are feasible given the vehicle's velocity and accelerations limits. The third level generates flyable, timed trajectories and the last one is the tracking controller that attempts to minimize the error between the robot measured trajectory and the reference trajectory.

This hierarchy is reflected in the structure and content of the book. Topics treated are: Modelling, Flight Planning, Trajectory Design and Control. Finally, some actual projects are described in the appendix. This volume will prove useful for researchers and practitioners working in Robotics and Automation, Aerospace Technology, Control and Artificial Intelligence.

Inhaltsverzeichnis

Frontmatter
Chapter 1. Introduction
Abstract
An aerial robot is a system capable of sustained flight with no direct human control and able to perform a specific task. A Lighter Than Air Robot (LTAR) is an unmanned lighter than air vehicle with sufficient autonomy. Robotic airships can also be called Aerobot. Lighter-Than-Air-Vehicles are becoming more popular in aerial missions. A Lighter Than Air Robot behaves and functions differently to a heavier than air craft: airplane and helicopter. It does not require any motor action to maintain a certain altitude and position in the space as it relies on low density gas inside the envelope to balance its own weight. It uses buoyancy to float in the air.
Yasmina Bestaoui Sebbane
Chapter 2. Modeling
Abstract
Nowadays, non rigid airships with a cigar shaped profile are the most common type. These airships do not have any rigid internal framework. The objective of this chapter is to present kinematics and dynamics models of a lighter than air robot, taking into account wind effect. Newton-Euler and Hamilton-Lagrange approaches are used for this discussion then the translational model is presented. Here, motion is referenced to a system of orthogonal body axes fixed in the airship, with the origin assumed to coincide with the bow. Finally, some aerology characteristics are briefly discussed.
Yasmina Bestaoui Sebbane
Chapter 3. Mission Planning
Abstract
Planning can be considered as the generation of a set of paths from a set of initial states to a set of goal states of a vehicle through an environment with obstacles. Many approaches have been investigated for solving these problems. All involve some kinds of simplification aiming to capture key elements of the task in a form suitable for practical computation. For many aerial robot applications, a point vehicle representation is usually used as an assumption that simplifies the problem.
Yasmina Bestaoui Sebbane
Chapter 4. Trajectory Design
Abstract
As the lighter than air robot is under-actuated, i.e. less control inputs than degrees of freedom, the set of feasible trajectory will be restricted and consequently, the problem of trajectory generation becomes more complicated than a simple interpolation. Care must be taken in the selection of the basic primitives.
Yasmina Bestaoui Sebbane
Chapter 5. Control
Abstract
The control methods implemented on lighter than air robots lie in two categories: traditional control methods and advanced control methods. The traditional control methods achieve autonomous control goals via classical control algorithms. These control methods have the advantage of being easily implemented and providing reliable control performance while the weaknesses include the costs of computation to model the system and tuning the control parameters. The most basic nonlinear control laws are the On-off control and Gain scheduling. Most of the advanced control methods are faced with highly nonlinear and time varying control system, in which it is difficult to obtain an accurate dynamic model of the LTAR and the environment. Several control methods have been developed such as back stepping control, robust control, model-prediction control and other intelligent control methods.
Yasmina Bestaoui Sebbane
Chapter 6. General Conclusions
Abstract
General conclusions and perspectives are presented in the sixth and last chapter.
Yasmina Bestaoui Sebbane
Backmatter
Metadaten
Titel
Lighter than Air Robots
verfasst von
Yasmina Bestaoui Sebbane
Copyright-Jahr
2012
Verlag
Springer Netherlands
Electronic ISBN
978-94-007-2663-5
Print ISBN
978-94-007-2662-8
DOI
https://doi.org/10.1007/978-94-007-2663-5

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