Self-Collision Detection and Prevention for Humanoid Robots

1. Self-Collision Detection and Preventionfor Humanoid Robots James Kuffner et al. presented by Jinsung Kwon

2. Mobile Robots are free of self-collisions in most cases Self-Collision

3. Self-Collision Ariticulated robots are typically at high risk of self-collision

4. Objective Develop efficient geometric method detect and prevent self-collision suitable for complex articulated robots H7 Humanoid (31 Links)

5. Challenges Large number of distance computations in short time N = 31 P = 435

6. Challenges Single distance computation itself is also very expensive

7. Strategies Eliminate unnecessary pairs from distance computation

8. Strategies Eliminate unnecessary pairs from distance computation

9. Strategies Protective Hulls approximation to the complicated geometry

10. Strategies Protective Hulls

11. Implementation Trajectory Sampling : discretization of the trajectory into a finite set of samples

12. Implementation No Collision if xmax < dmin during ∆t with dx = J dq |dq/dt| < (dq/dt)max Velocity Bounds and Collision-free Guarantees xmax dmin

13. Implementation Voronoi-clip for distance computation Running time depends on the geometric complexity and posture changed Running relatively in constant time with high coherency Limited to convex polyhedrons

14. 0 1 2 3 1 2 3 4 2 3 4 5 3 4 5 6 Implementation Final Posture by Emergency Stop Control Strategy Read joystick command Calculate 3-step trajectory Check new trajectory for self-collision

15. Results

16. Results

17. Results Comparison

18. Future Work Automatic selection of active pairs for given joint angle ranges Alternative minimum distance determination method allowing non-convex protective hulls