1. Introduction to RoboticsNavigation April 5, 2010

2. Review: Localization Localization is probabilistic Error propagation law Markov localization and Kalman Filter Simultaneous Localization and Mapping

3. Last Exercise Beacon-based Line-based Maps are used for LOCALIZATION

4. Today: Navigation How to find a collision-free, shortest path from A to B? Two approaches: Local planning: go towards goal while avoiding obstacles Global planning: calculate shortest path offline

5. Global Planning Workspace Configuration Space

6. Graph-based and Potential-field Planning Grid-decomposition Visibility Graph Potential field

7. Configuration Space Grow obstacles at least by radius of robot

8. Voronoi Decomposition

9. Exact Cell Decomposition

10. Adaptive Cell Decomposition

11. Graph-based planning Dijkstra/ Wavefront A*

12. Rapidly Exploring Random Trees Select a random point in the configuration space Grow tree into this direction from the closest point already in the graph Explores space quickly, and eventually completely

13. Potential-field based Planning Potential given by Distance to obstacles Direction to goal Possible to construct more complex behaviors

14. Calculate virtual force pulling at the robot Differential wheel robot Left wheel = Fx – Fy Right wheel = Fx + Fy Potential-Field based Planning x y

15. Reactive Obstacle Avoidance Goal Braitenberg behavior not sufficient (U-obstacle) Classic: bug-algorithms Easy to construct sub-optimal results

16. Vector Field Histogram

17. Practice Localization, actuation and obstacles are uncertain Combination of Local and Global Techniques

18. Debate Outline Constructive speeches 10 minutes pro 10 minutes contra Rebuttal 3 minutes affirmative 3 minutes negative Discussion and cross examination 5-10 minutes 4 Debates total

19. Debates Social: Robots putting humans out of work is a risk that needs to be mitigated. Robots should not have the capability to autonomously discharge weapons. Robotic cars should not be allowed to participate in urban traffic. … Technical: Swarms of simple robots are more attractive than monolithic, more capable robots. Robots do not need to be as cognitive as humans in order to be useful as making the environment intelligent is sufficient. Robots need to be made differently than from links, joints, and gears in order to reach the agility of people. … In both cases: debates should be driven by verifiable, technical arguments!

20. Debates Social: D1: Robots putting humans out of work is a risk that needs to be mitigated. D2: Robots should not have the capability to autonomously discharge weapons / drive around in cities (autonomous cars). Technical: D3: Robots do not need to be as cognitive as humans in order to be useful as making the environment intelligent is sufficient. D4: Robots need to be made differently than from links, joints, and gears in order to reach the agility of people. … In both cases: debates should be driven by verifiable, technical arguments!

21. Random assignments

22. Organization Week 12 + 13: Debates http://courses.csail.mit.edu/6.141/spring2009/pub/debates/Debates.html Week 14: Graduate student presentations Week 15: Final presentations Final exam: Monday, May 3 7:30 p.m. - 10:00 p.m.