Rotational.world File Reference

Detailed Description

A highly contrained parallel platform so that it only has rotational degrees of freedom. We took this example form Juan Cortés as a test for our path planner.

We used this example in our IJRR-12 paper.

The key data for this problem are:

Ambient space dimension 27
Configuration space dimension 3
Average planning time with bin/cuikatlasGBF (in seconds) 0.7

Note that these figures correspond to a redundant formulation of the problem. A non-redundant formulation produces lower dimensional ambient and configuration spaces, but this does not necessarily result in lower execution times. Moreover, we only consider collisions between the moved peg and the obstacles (in blue), but not self-collisions of the parellel mechanisms (leg crossing might occur in some cases).

This example is treated following these steps (from the main CuikSuite folder):

  • Adjust the parameters: Different algorithms use different parameter settings. Just check the parameter file (Rotational.param) and uncomment the appropriate lines. Moreover, ensure that parameter REPRESENTATION is set to LINKS (or just not set).
  • Solve the path planning problem: using the graph-based search
  • An alternative way to solve the path planning problem: using a RRT-like algorithm
  • Solving with pre-existing methods: Both methods are RRT-based
  • Visualize the solution path:
    • scripts/cuikplayer examples/ParallelPlatform/Rotational examples/ParallelPlatform/Rotational_path
  • Smooth the path:
  • Visualize the smoothed path:
    • scripts/cuikplayer examples/ParallelPlatform/Rotational examples/ParallelPlatform/Rotational_path_s

Definition in file Rotational.world.