Path planning for a mobile robot

in an unknown environment using D* lite

Final report[Special Topics in Robotics]

Jakub Tomášek

Outline

1.Introduction– Homemate robot

– Project definition

2.My solution of the problem– Obstacle detection and mapping

– D* lite

– Moving the robot

3.Conclusion, remarks, questions

Homemate v3

● Intelligent Systems Research Institute

+ Yujin

● Mobile manipulation robot

● Humanoid with one arm :-)

● Helping elderly

Homemate v3

● 10 IR range-finders● 8 motors● Robotic hand● Stargazer● 3D camera

● Linux machine controls HW

● Windows notebook is the brain– Ethernet

Note: stargazer

Project goal

● Navigation in unknown environment for Homemate

● D* lite● C++● Obstacle detection using

processed 3D image in form of octree cells

Environment

2 by 3 metres marked area

Outline

1.Introduction– Homemate robot

– Project definition

2.My solution of the problem– Obstacle detection and mapping

– D* lite

– Moving the robot

3.Conclusion, remarks, questions

3D vision and octree cell representation

ISRC develops cognitive recognition systemOctree cells are used for object segmentationand recognition to make decision

Lee et al. 2012

Obstacle detection

● I simply assume that each there is an obstacle in place of the octree cell

● Mapping of the octree cells into 2D map

● Grid size: 10cm

Octree mapping

Octree mapping

Outline

1.Introduction– Homemate robot

– Project definition

2.My solution of the problem– Obstacle detection and mapping

– D* lite

– Moving the robot

3.Conclusion, remarks, questions

D* lite● Koenig, S., and M. Likhachev. “Improved Fast Replanning

for Robot Navigation in Unknown Terrain.” In IEEE International Conference on Robotics and Automation, 2002. Proceedings. ICRA ’02, 1:968–975 vol.1, 2002. doi:10.1109/ROBOT.2002.1013481.

● Koenig, S., and M. Likhachev. “Fast Replanning for Navigation in Unknown Terrain.” IEEE Transactions on Robotics 21, no. 3 (2005): 354–363. doi:10.1109/TRO.2004.838026.

Interface

Outline

1.Introduction– Homemate robot

– Project definition

2.My solution of the problem– Obstacle detection and mapping

– D* lite

– Moving the robot

3.Conclusion, remarks, questions

Moving the robot

Moving the robot in reality: troubles and issues

● Closed platform : limited control of the robot– Move forward/backward X cm

– Turn left/right X Degrees

● Cannot apply any feedback trajectory tracker → moving

● But feedforward and slipping → very inaccurate → limiting the grid size

Outline

1.Introduction– Homemate robot

– Project definition

2.My solution of the problem– Obstacle detection and mapping

– D* lite

– Moving the robot

3.Conclusion, remarks, questions

Conclusion

What I achieved● D* lite and obstacle

mapping seem to work well

● Robot is most of time able to navigate to the goal in the simple environment but it is troublesome

Problems● Not obstacle forgetting● In more complex

environment the robot fails

What did I taken from the project

● I wish I use a smaller robot● Robots are fun but life is never as easy as the

simulations● It is useful to know Korean when working on Korean

computer :-)● Confirmed again Murphy's laws

– "Anything that can go wrong, will go wrong".

→Opt for more theoretical thesis :-)

Special thanks to

Ahmed M. Naguib

Thank you. Please ask me anything!