THESIS COLLOQUIUM

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THESIS COLLOQUIUM. Collision avoidance and coalition formation of multiple unmanned aerial vehicles in high density traffic environments. Joel George M. - PowerPoint PPT Presentation

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THESIS COLLOQUIUMCollision avoidance and coalition formation of multiple unmanned aerial vehicles in high density traffic environmentsJoel George M11Welcome, all, to the colloquium of the thesis titled Collision avoidance and coalition formation of multiple unmanned aerial vehicles in high density traffic environments. it was nevertheless - the first time in the history of the world in which a machine carrying a man had raised itself by its own power into the air in full flight, had sailed forward without reduction of speed, and had finally landed at a point as high as that from which it started.Details of first flight:Speed = 6.8 miles/hourRange = 120 feetAltitude = 10 feetOrville Wright22Orville Wright, who flew the first recorded heavier than air powered flight in 1903, once remarked it was nevertheless - the first time in the history of the world in which a machine carrying a man had raised itself by its own power into the air in full flight, (had sailed forward without reduction of speed, and had finally landed at a point as high as that from which it started.) I unquote.

The first flight, by Orville, covered 120 feet (37 m) at a speed of only 6.8 miles per hour (10.9 km/h) at about 10 feet (3.0 m) above the ground.Faster, Farther, Higher (and Safer)Slogan of aircraft design industryBoundaries of speed, altitude, range, and endurance have been pushedfurther and further33Ever since that modest flight, the aircraft design industry has made a huge leap, led by the slogan Faster, Farther, Higher (and Safer). And, over the years, boundaries of speed, height, range and endurance have been pushed farther and farther.Aircraft kept the tag machine carrying a manPresence of man in aircraft was always an important design consideration44However, aircraft always had had the tag of, as Orville Wright said, machine carrying a man. Man was always there in the design loop. Aircraft were designed with human considerations; consideration that human beings are going to be inside, or at least going to fly, these machines.

The questions that curtailed the imagination, creativity, and constructiveness of aircraft designers were like:

What is the point of designing an aircraft that can fly for 48 hours non-stop, when the pilot who is going to fly it is going to get fatigued in a few hours?

What is the point of designing a fighter aircraft that can take 16-g such a capability will give a fighter aircraft significant maneuvering advantage over the enemy. But, what is the point in such a design when the pilot flying it will black out at just 7 or 8-g? Elimination of pilot from a manned combat aircraft removes many of the conventional design constraints

This at once throws open the design parameter space and dramatic improvements in performance measures like increased speed, range, maneuverability, and payload can be achieved.Late Dr. S Pradeep55As my previous thesis supervisor, Late Dr. S Pradeep, remarked Elimination of pilot from a manned combat aircraft removes many of the conventional design constraints This at once throws open the design parameter space and dramatic improvements in performance measures like increased speed, range, maneuverability, and payload can be achieved.

Although he said this about an unmanned combat aerial vehicle, this statement is, in general, true about any unmanned aerial vehicle.Dull, Dirty, and Dangerous missionsIn some missions, human presence need not be thereIn some other missions, human presence should not be thereUnmanned Aerial Vehicles find applications inWhy Unmanned Aerial Vehicles (UAVs)?66Apart from these, there are some dull missions, like oil pipeline monitoring, in which the human presence need not be there. At the same time, there are some other set of dangerous missions, like hazardous chemical or nuclear leakage inspections, where the human presence should not be there. Thus, UAVs find a lot of applications in Dull, Dirty, and Dangerous missions.Why UAVs?Factors compelling the use of Unmanned Aerial Vehicles (UAVs)Design freedom (mission specific designs)

Dull, dirty, and dangerous missions

Low cost, portability, absence to human risk, 77To summarize, some of the factors that make the use of UAVs inevitable are:

Design freedom: Aircraft can be designed specifically tailored to certain missions without other considerations that are not specific and important to the mission.

UAVs find use in, as said earlier, dull, dirty, and dangerous missions, and

UAVs are usually less expensive than a manned aircraft; they are usually small, thus facilitating portability, and there is complete absence to human risk.

Why autonomous UAVs?UAVs can be remotely pilotedHowever, desirable to make UAVs autonomous88Given the inevitability of the use of UAVs for certain missions, it is desirable that they are made autonomous than being remotely controlled. This is because a lack of autonomy will cause some of the difficulties associated with manned flight, like pilot fatigue, to still linger around.Why multiple UAVs?Use of multiple UAVs leads to coordination problemsUAVs are often smallCollision avoidance, coalition formation, formation flying, Some missions are more effectively done by multiple UAVs99Since UAVs are usually small owing to portability requirements, it is often necessary to deploy a team of UAVs to accomplish certain missions. Also, there are some missions, like search and surveillance, that are more efficiently done by a group rather than a single UAV alone. In addition, the use of multiple UAVs will add to missions, a robustness that is achieved through redundancy.

Although the use of multiple UAVs for missions have several advantages, it will lead to operational issues. The UAVs will have to cooperate and coordinate with other UAVs, in the same as well as other groups, to effectively carry out the respective missions; especially so in high density traffic situations.

Some of the multiple UAV problems that require coordination and cooperation are: collision avoidance among UAVs, coalition formation, formation flying, This thesis addresses the problems ofCollision avoidance,

Coalition formation, and

Mission involving collision avoidance and coalition formationof multiple UAVs in high density traffic environments1010This thesis addresses the problems of collision avoidance and coalition formation among multiple UAVs in very high density traffic environments and gives conceptually simple and easy to implement algorithms, and discusses the applications of these in multiple UAV missions.OUTLINECHAPTER 1Introduction

CHAPTER 2Collision avoidance among multiple UAVs

CHAPTER 3Collision avoidance with realistic UAV models

CHAPTER 4Coalition formation with global communication

CHAPTER 5Coalition formation with limited communication

CHAPTER 6Coalition formation and collision avoidance in multiple UAV missions

CHAPTER 7Conclusions1111The thesis is organized as follows:

Chapter 1 introduces the problems that we address in the thesis, and reviews the relevant literature.

In Chapter 2, we develop collision avoidance algorithms for deconfliction in high density traffic environments. Algorithms are developed to handle both two and three dimensional conflicts; and through simulations we show the efficacy of the proposed algorithms.

In Chapter 3, we implement the collision avoidance algorithms developed on realistic UAV models, in simulation.

Chapter 4 addresses the problem of coalition formation among multiple UAVs to search and prosecute stationary targets in a region of interest.

Chapter 5 extends the algorithm developed in Chapter 4 to the case where the UAVs have only limited communication ranges. In this chapter, we also consider the prosecution of targets that are moving/maneuvering.

In Chapter 6, we look at some multiple UAV missions that require collision avoidance, or coalition formation, or both. In particular, we consider multiple UAV rendezvous under collision avoidance, and coalition formation under collision avoidance.

Chapter 7 concludes the thesis with a summary, discussion of some of the main results, and directions for further work in the area.CHAPTER 1Introduction1212Chapter 1. Introduction.Collision avoidance

Using information of positions and velocities of UAVs in the sensor range, a UAV needs to find an efficient safe path to destinationA safe path means that no UAV should come within each others safety zones during any time of flight

Efficiency less deviation from nominal path1313One common sub-problem in all multiple UAV missions is that the UAVs need to avoid each other. The problem of collision avoidance among UAVs acquires great importance in high density UAV traffic environments.

The figure depicts a typical scenario. We have several UAVs in free-flight, flying to their respective destinations. Each UAV has a limited sensor range within which it can detect the presence of, and positions and velocities of other UAVs. Each UAV has a safety zone around it; in the figure, for clarity, safety zone of only UAV U1 is shown.

UAVs on their way to respective destination encounter conflicts; sometimes multiple conflicts at same time owing to the high density. The objective is to find an algorithm, which when implemented by every UAV will result in efficient safe paths. A safe path means that no UAV should come within each others safety zones during any time of flight. Efficiency would mean that deviation of UAVs from their nominal paths, owing to collision avoidance maneuvers, are minimal.

Have been looked at from the robotics and air traffic management points of viewGround based robots can stop to finish the calculations Collision avoidance algorithms addressing air traffic management problem