Problem setting Low quality paths
Often long detours Discontinuity Unnecessary motions
Quality criteria Length Clearance Combination
Path Quality – Length
Path pruning Fast and simple heuristic Translational dist. improves
considerably Rotation is more difficult to remove
Path Quality – Length
Weakness of the shortcut heuristic Path can still contain many redundant
(rotational) motions Creating shortcuts on large portions
will fail Partial shortcut
Query path Shortcut Partial shortcut
Path Quality – Clearance Method
Remove redundant nodes Retract path to medial axis Remove branches
Can help improving path length
Query path Retracted path No branches
Path Quality – Combination Technique
Retract path to medial axis Increase size of robots Create partial shortcuts
Result Reasonable short path Path has a particular minimum
amount of clearance where it is possible
Experimental Setup – Path Length
Environment SAMPLE 3 test scenes/paths
Focus Free flying objects Post processing
Experiments – Simple Corridor Simple scene, cylinder Many motions are redundant Redundant motions are easy to remove
Experiments – Simple Corridor Simple scene, cylinder Many motions are redundant Redundant motions are easy to remove
0
200
400
600
Initial path Redundantnodes
Shortcut MA +Shortcut
Partialshortcut
MA+Partialshortcut
Optimal
Pat
h l
eng
th
translation
rotation400%
27% 16% 14% 1% 2% 0%
Experiments – Corridor Elbow shaped object is forced to rotate Little clearance to corridors
0
250
500
750
Initial path Redundantnodes
Shortcut MA +Shortcut
Partialshortcut
MA+Partialshortcut
Optimal
Pat
h l
eng
th
translation
rotation
256%
65%24% 24
%11% 5% 0%
Experiments – Hole Object must rotate to get through the
hole Clearance is small inside the hole
0
40
80
120
Initial path Redundantnodes
Shortcut MA + Shortcut Partial shortcut MA+Partialshortcut
Optimal
Pat
h le
ng
th
translation
rotation
41% 14% 0%
184%
112%
36%
23%