[gp][1st seminar][presentation]

Computer and Information Science | Computer Systems Department

1st Seminar 28/2/2013

Co-Swarm: Cooperative area exploration using a swarm of mobile robots February 2013 11st Seminar

http://coswarm.wordpress.com/

• Team – Ahmed Mohamed Emad– Abdelrahman Ehab Soliman– Muhammed Aly Huessin– Anas Awad Ismail

• Academic Supervisors – Prof. Hossam El-Din Fahem– Dr. Wael S. El-Kilany– TA. Agwad Hammad

Team Members



• Area Exploration Problem:– Problem definition.– Previous Work.

• Cooperative Swarm:– Swarm Robotics – Why Swarm?!– Goal. – Frontier-Based Exploration. – System Architecture.

• Robots Capabilities:– Sensors, Brains, Cameras, … etc.– Tools and Environment.

• Timeline:– Our Status.

Outline Introduction Co-Swarm Timeline References

Outline



Problem Definition “In Robotics, the exploration problem deals with the use

of a robot to maximize the knowledge over a particular area. The exploration problem arises in mapping and search and rescue situations, where an environment might be dangerous or inaccessible to humans ”



Introduction|Area Exploration


Problem Overview– The exploration problems appeared when the humans think to use

robots to discover unknown areas that may be dangerous or inaccessible for humans.

– Robot needs a map to operate in a particular environment.

– Autonomous Exploration : The ability of robots to autonomously travel around an unknown environment gathering the necessary information to obtain a useful map for navigation.

– Optimization Problem





Previous Work• In absence of global position information, (SLAM) techniques are

deployed to construct a map.• State of the art:

– Classic non-coordinated strategies– Classic coordinated strategies– Integrated non-coordinated strategies – Integrated coordinated strategies

Outline Introduction Co-Swarm Timeline Our Status




Previous Work• In absence of global position information, (SLAM) techniques are

deployed to construct a map.• State of the art:

– Classic non-coordinated strategies– Classic coordinated strategies

• Frontier-Based Exploration using Multiple Robots – Brain Yamuchi 1998

– Integrated non-coordinated strategies – Integrated coordinated strategies

Outline Introduction Co-Swarm Timeline Our Status




What’s Swarm ?!!• New bio-inspired approach to control the coordination of (Multi-

Robot System)MRS, which consists of large numbers of mostly simple physical robots.

• This collective behavior leads to the field of Artificial Swarm Intelligence.


Co-Swarm | Swarm Robotics



Why Swarm ?!!• Simple and Elegant.

– Can be represented by State Machine.

• Scalable.• Decentralized.• Usage of local interactions.





Goal“Speedup the area exploration mission using swarm of Mobile Robots”





Central Idea • Gain the most new information about the world.• Move to the boundary between open space and uncharted space.


Co-Swarm |Frontier-Based Exploration



Evidence Grid• Our Spatial Representation for the Environment.• A Cartesian Grid containing cells and each cell contains its state

whether it is Open , Occupied or unknown.

Frontier Detection• Frontiers are regions on the boundary between open space and

unexplored space.• A process analogous to edge detection and region extraction in

computer vision is used to find the boundaries between open space and unknown space.





Navigate to Frontiers• The robot attempts to navigate to the nearest accessible

unvisited frontier.• Motion Planning with Obstacle Avoidance.• Path Finding Algorithm A*.





Multi-Robot Exploration






Co-Swarm |System Architecture



Robocars• 4-wheels car:

– with 4 DC motors and encoders


Co-Swarm |Capabilities



Microcontroller• ISP flash memory for 128 KB Internal Programming.• 4 KB EEPROM.• 4 KB Internal SRAM.





Sensors• Position Sensitive Device (PSD)

– Range: 10 cm 80 cm

• Ultrasonic :– Range: 10 cm 10 m

• Infra-red:– For line tracking Applications





Bluetooth Module• Used in communication to exchange map information





Camera• Our system will not depend on vision system.• Capturing the surroundings and pass the data to a base

station.– 3D Area reconstruction.





Brains





• AVR Studio


Co-Swarm |Tools and Environment




Timeline ID Task name start finish 11 12 1 2 3 4 5

1 problem characterization 1/11 15/11

2 literature survey on cooperative mapping using multirobot systems

15/11 1/1

3 Testing robo-car capabilities 15/11 15/12

4 Developing a set of simple behaviors to control the motion of

robo-car, obstacle avoidance

25/1 20/2

5 Developing a robo-car framework to work with

20/2 6/3

6 Implementing exploration on one robot

25/2 10/3

7 Developing a fusion technique for combining local maps into global

map

10/3 5/4




Timeline

ID Task name Start finish

11 12 1 2 3 4 5

8 Studying coordinated mobility model mobility and anti-flocking

model mobility and their effect on the mapping process

10/3 5/4

9 Implementation 15/11 1/5

10 Performance evaluation and refinement

15/4 15/5

11 Final Report 1/12 30/5

12 Presentation and final delivery



Framework • Obstacle detection and Avoidance (1 moving robot)


Timeline| Our Status



Framework • Obstacle detection and Avoidance (3 moving robots)





Framework• Robot Motion:– Description – PID Control








D=2*∏*rr= 42 mm

∅=D/RR= 116 mm

VL /(R-L/2) = VR /(R+L/2)L = 24 cm





Framework – Control Theory

• Systems (Velocity) : it is the component which describe what is the system doing now .• System output (Rotations): is the result or the signals which generating from the system .• Sensor(Encoder): it is the feedback system which can sense the output of the system .• Reference(Target Velocity) : it is the target of the system or what we need the system actually

do.• Controller(PWM) : the component which convert the Measured error to control signals.


Framework • Motion Control : PID Control





Framework • Motion Control :

– PID Control effect





Framework • PID Control:





Framework • Communication:

– Sending and receiving data using Bluetooth





Area Exploration• We finished the first phase of Frontier-Based approach





Area Exploration




Stop

Avoid Obstacles

Rotate

Move

Gather Information & Creating Local Grid

Explore

No Avail. Path

Avail. Path

Find obstacle

New pathReached way point

New path

New path


Area Exploration• Now , We are working on the following :-

– Implementation of a mapping technique.– Implementation path planning:

• Data Structure Metric Mapping.• Algorithm A* for static environment .





• Frontier-Based Exploration Using Multiple Robots – Brain Yamauchi – 1998.

• A Frontier-Based Approach for Autonomous Exploration – Brain Yamauchi – 1997.

• A comparison of path planning strategies for autonomous exploration and mapping of unknown environments – Miguel Juliá – 2012.

• Probabilistic Robotics – Sebastian Thrun.

• An Introduction to AI Robotics – Robin R. Murphy.

• Embedded Robotics – Thomas Braunl.

• Robocar user Manual.


References



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