Multiple UAV Rendezvous with Collision Avoidance

Joel George and Debasish GhoseGuidance, Control, and Decision Systems Laboratory

(GCDSL)Department of Aerospace Engineering,Indian Institute of Science, Bangalore

India 560012.

Introduction Rendezvous: meeting at a pre-planned time and

place Rendezvous of multiple UAVs

For simultaneous deployment of resources To exchange resources or critical information

Rendezvous of multiple UAVs when some of the UAVs have to do collision avoidance maneuvers en route

Assumptions Kinematic UAV model

is the position, is the velocity, is the heading, and is the turn rate command of UAV

Global communication between UAVs

cossin

i i i

i i i

i i

x vy v

a

( , )i ix y i

iaiv

i

Solution Approach Rendezvous via consensus on Estimated Time of

Arrival (ETA) at target ETA at target obtained from Dubins path to target Arrive at a consensus on ETA by adjusting

velocities.

(ETA )ii iv f N

Solution Approach

Average consensus

In principle, any consensus protocol can be used. Average consensus protocol is used for the purpose of illustration

1(ETA ) ETA ETA| |i

i

i i jji

f

NNN

Handling velocity bounds If a UAV hits the maximum velocity bound, it

stays with that velocity If a UAV hits the minimum velocity bound, it

stays with that velocity and in addition does a wandering maneuver (move away from target)

Wandering maneuver example Example of a case where one UAV (red) hits upper velocity bound while

other (green) hits lower velocity bound but still achieves a rendezvous

Rendezvous without collision avoidance Example of rendezvous of 10 UAVs

Rendezvous with collision avoidance Rendezvous of 5 UAVs with collision avoidance

Target tracking Target tracking with a stand-off radius Target tracking can be achieved by a little

modification in the rendezvous via consensus algorithm

Stand-off radius achieved by keeping the ETA to target constant

Target tracking Tracking a stationary target

Target tracking Tracking moving target

Remarks The algorithm developed for rendezvous via

consensus can be modified by adding a ‘bias’ to address the cooperative timing problem

Summary Algorithm for multiple UAV rendezvous under

collision avoidance achieved via consensus on ETA to target