MaritimeSurveillance

borderpatrol

CommercialJet

StratosphericTelecommunications

Airship

High-AltitudeImagery

Tactical LawEnforcement

EnvironmentalSensing

Media/TrafficReporting

Velocity Obstacle (absolute)Translations of the relative

VO along ��’

Every velocity vector ofUAV A lying inside VOAB arebound to collide with UAV B

Shadowof UAV BVelocity

Velocity Obstacle (relative)A triangle limited by the two tangent

line of UAV B avoidance spherefrom UAV A

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AvoidanceSphere

UAV AUAV B

Distance

RelativeVelocity

OriginalFlight Path

Inside cooperative sphereAvoidance maneuvers arebased on cooperative rules,while still considering theoriginal flight path

Inside non-cooperative sphereAvoidance maneuvers are strictlyconducted to escape as soon aspossible to safety

Protected Zone

Non-cooperativeSphere

CooperativeSphereTraffic

WarningSphere

1.1 span40 sec25 sec

1.5 sec

1% 0.001% 0% 0.003% 0% 0.005% 0% 0.007% 0%2.5% 4% 1%

Collision Probabilitiesvia MonteCarlo Simulationin Area 1 km x 1 km

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BackgroundLike any other technology which first started at military bases,UAVs will start affecting civilian live in just a couple years fromnow. Currently there are already industries that provides lowend UAVs technologies for various non-military purpose, mostof them are remote-controlled toys. However, with theincreasingly faster advancement of technology, these UAVswill soon be more than toys. Department like Police and FireBrigade began to count the possibility of deploying UAVs forspecific missions, frequently, and in a non-secluded area.Previous researches give several predictions on what willbecome of UAVs in the future that affects civilians life.

Civilian purposes UAVs will of course required to fly in a non-secluded area, or even in some populated area. This situationcan be hazardous, for the (1) UAV itself, (2) other (civilians)UAVs, (3) the manned-flight, and most importantly, (4) peoplein the flight area. Therefore, in order to be used widely in anon-secluded area, or also known as the National AirspaceSystem (NAS), UAVs are required to have an well standardizedCollision Avoidance System, which should be able todemonstrate an equivalent level of safety.

Thus, the research aims to define and investigate theautonomous collision avoidance system (ACAS) forUAVs, in context of integrating UAVs into the NationalAirspace System.

Cooperative and Non-cooperative Avoidance

The avoidance structure for UAVs is set to have two layer ofsafety. These are the Cooperative, and the Non-cooperativeavoidance layer. The first one use a common rules ofavoidance which expected to be followed by every UAVinvolved. The later is avoidance purely by trheating the otheUAV as a rogue obstacle/intruder

Avoidance Algorithm: Velocity Obstacle Method

A method called the Velocity Obstacle (VO) Method , orsometime the Forbidden Zone Beam Method, is used to defineavoidance criteria. The VO-method was chosen due to itssimple implementation and geometrically understandablecompare to others. To be suitable for the implementation inUAVs ACAS, however, several modifications were made,producing a new branch of the Velocity Obstacle Method,which be referred as the Selective Velocity Obstacle Method(SVO).

SVO will also acomodate rules that form the cooperativeautonomous collision avoidance system for UAVs (Co-ACAS)

Rules of Cooperative Avoidance

Adapted form the Rules of Air in the manned-flight, the rulesfor are:

1. On encounter, The one on the right handhave the right of way

2. On encounter, both UAV should move to theright side

3. On , the one that are about to be takenover have the right of way

4. Avoidance should not go over or under, or in front ofother UAV that have right of way

Having the Right of way means the UAV could keep goingmaintaining its original flight path, while expecting the otherUAV will conduct the avoidance, hence resolve the conflict. Ifnot resolved, then the non-cooperative avoidance should beconducted.

Converging

Head-on

Taking Over

SimulationsUsing the VO-method and cooperative avoidance rules, a 2-Dimensional simulations were conducted for all converging,head-on and taking over encounters. The simulation weredone using Matlab program that was developed throughoutthis research, which are able to simulate up to 5 agents of UAVin various conditions and configurations.

Collision Probabilities (Monte Carlo Simulations)

To predict the collision probabilities from various initialconditions and configurations, several Monte Carlosimulations were set. Using 1000000 number of samples, andrandomly distributed positions (Cartesian), airspeed, andheadings.

Three set of Monte Carlo Simulation were conducted, i.e, forscenario (1) without any ACAS implemented, (2) with ACASimplemented but no rules (non-cooperative), and (3) with Co-ACAS implemented.

The result were in favor of the Co-ACAS, resulting zerocollisions in all samples.

1. SenseDepends on sensorscapabilities, obstacle

type, and environmentalconditions

2. DetectCalculate a few steps aheadthe probabilities of collisions,depends on UAVs sizes andVelocities, and Headings

3. AvoidanceChange flight pathto ensure safety.Depends on UAVsmaneuverabilityand performance.

UAV AWith Sense, Detect,

and Avoid System

UAV BThe Obstacle

sensing range

Non-Cooperative Avoidance

• just avoid as fast as possible, using everydegree of freedom (thus, )

• Avoidance could be conductedsphere, or

, whichever comes first

• Avoidance conducted to to theprotective sphere

• Sensors areNoise are expected

Several Sensor use in the research are new and small withvery limited performance to be light for UAVs. This create anew challenge of avoidance: Sense and Avoid, withoutDetection

No Rules,3D

at the edge of the 1.5sas soon as obstacle sensed and/or

conflict detected

avoid collisions

on-boards, high frequency, and shortranges.

and its still continuing

What Next?

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Real experiment on UAVs Cooperative Avoidance usingwith simulated ADS-B

Setting up standard requirements for UAV to integratewith the National Airspace System

Setting up standard sensor requiremnets for specific UAVcategories

Hybrid Modeling on avoidance and control

Simulation for Non-cooperative avoidance and escapemaneuver

Publications- Y.I. Jenie, E. van Kampen, B. Remes (2013) “Cooperative Autonomous Collision Avoidance System for Unmanned Aerial Vehicles”, CEAS EuroGNC 2013 conference, Delft (To be Presented)- Y.I. Jenie, E. van Kampen, C.C. de Visser, Q.P. Chu (2013) “Selective Velocity Obstacle Method for Cooperative Autonomous Collision Avoidance System for UAVs”, AIAA Guidance,

Navigation and Control Conference, Boston Massachusetts (Abstract Submitted)- Y.I. Jenie, (2013) “Hybrid Modeling of Velocity Obstacle Method in Autonomous Collision Avoidance System for UAVs “, AIAA Modeling and

Simulation Technology Conference,E. van Kampen, C.C. de Visser, Q.P. Chu

Boston Massachusetts (Abstract Submitted)

Predictions on what will become of UAVs in the future that affectscivilians life

Cooperative and Non-Cooperative Avoidance structure definitions From top, simulations of (1) Converging encounter, (2) Head-on Encouinter(3) Taking Over, and (4) Eight symmetric converging

Definitions of Sense-Detect and Avoid. Several sensors are so light andsimple that cannot be used to conduct detection

Velocity Obstacle Method graphical explanations

Monte Carlo simulation result on collision probabilities of cooperativeavoidance for UAV, Number of Samples : 1000000

Autonomous collision

avoidance system for UAVsTowards integration with National Airspace System

PhD Candidate : Yazdi Ibrahim JenieDepartment: C&OSection: Control and SimulationsSupervisor: E. van KampenPromoter: M. MulderStart date : 06-06-2011Funding: IDB Merit for High TechnologyCooperations: -

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space

Engin

eering