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

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

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

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

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

Challenges Single distance computation itself is also very expensive

Strategies Eliminate unnecessary pairs from distance computation

Strategies

Strategies Protective Hulls approximation to the complicated geometry

Strategies Protective Hulls

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

Implementation Velocity Bounds and Collision-free Guarantees d min x max No Collision if x max < d min during ∆t with dx = J dq |dq/dt| < (dq/dt) max

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

Implementation Control Strategy Read joystick command Calculate 3-step trajectory Check new trajectory for self-collision Final Posture by Emergency Stop

Results

Results

Results Comparison

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