On Improving the Clearance for Robots in High-Dimensional Configuration Spaces

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On Improving the Clearance for Robots in High-Dimensional Configuration Spaces Roland Geraerts and Mark Overmars IROS 2005

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On Improving the Clearance for Robots in High-Dimensional Configuration Spaces. Roland Geraerts and Mark Overmars IROS 2005. Outline. Related work Retraction algorithm Algorithmic details Experiments Conclusions. d. d. Related Work. Preprocessing techniques - PowerPoint PPT Presentation

Transcript of On Improving the Clearance for Robots in High-Dimensional Configuration Spaces

Page 1: On Improving the Clearance for Robots in High-Dimensional Configuration Spaces

On Improving the Clearance for Robots in High-Dimensional Configuration Spaces

Roland Geraerts and Mark OvermarsIROS 2005

Page 2: On Improving the Clearance for Robots in High-Dimensional Configuration Spaces

Outline• Related work• Retraction algorithm• Algorithmic details• Experiments• Conclusions

Page 3: On Improving the Clearance for Robots in High-Dimensional Configuration Spaces

Related Work• Preprocessing techniques

– Extract path from graph with cycles– Create path along the medial axis

• Post processing technique– Retract path to the medial axis (MA)

d

d

Page 4: On Improving the Clearance for Robots in High-Dimensional Configuration Spaces

Related Work• Preprocessing techniques

– Extract path from graph with cycles– Create path along the medial axis

• Post processing technique– Retract path to the medial axis (MA)

Page 5: On Improving the Clearance for Robots in High-Dimensional Configuration Spaces

Related Work• Preprocessing techniques

– Extract path from graph with cycles– Create path along the medial axis

• Post processing technique– Retract path to the medial axis (MA)

Initial path Retraction to MA Retraction to ridges

Page 6: On Improving the Clearance for Robots in High-Dimensional Configuration Spaces

Retraction Algorithm

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Algorithmic Details – Metric

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Algorithmic Details – Vector

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Algorithmic Details – Validate

maximumstep size

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Experimental Setup• Pentium 4 (2.66GHz)• Comparison of retraction techniques

– Workspace (1 run)– Configuration space (100 runs)

• Environments / paths

planar (2 dofs) hole (6 dofs) manipulator (6 dofs)

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Experimental Results

min avg timeinitialworkspaceC-space

0.351.801.79

2.844.494.47

0.01.5

15.0

initial paths workspace C-space

n.a.

Clearance

min avg timeinitialworkspaceC-space

0.210.441.27

1.553.374.69

0.01.5

50.0

min avg timeinitialworkspaceC-space

0.01 n.a.0.16

0.13 n.a.0.33

0.0 n.a.60.0

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Conclusions• Clearance along paths is improved

– No complicated data structures are needed– The algorithm can handle robots with an

arbitrary amount of DOFs• Running times are too high for online usage

– Does not matter for high-cost environments– Smarter implementation decreased the running

times by an order of magnitude

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Current Work• Retraction of a roadmap yields online performance

Reachability roadmap Retracted roadmap

Page 14: On Improving the Clearance for Robots in High-Dimensional Configuration Spaces

Current Work• Retraction of a roadmap yields online performance

Reachability roadmap Retracted roadmap