search

haosulab / MPlib

a Lightweight Motion Planning Package
https://motion-planning-lib.readthedocs.io/
MIT License
109 stars 18 forks source link

Investigate why rrt connect results in jagged paths #12

Closed Lexseal closed 9 months ago

Lexseal commented 10 months ago

When planning with rrt connect, the arm frequently goes back and forth before finally reaching the goal pose. Moreover, even when there is a straight collision-free trajectory, the arm does not usually take this path.

As far as I remember, the moveit planner does not make such movements using the same rrt connect.

Steps to take:

  1. Set up similar scene in rviz that resembles the scene inside examples/avoid_collision.py
  2. Try moveit with rrt connect on that scene
  3. Compare the results and try some other planning algorithms
Lexseal commented 10 months ago

Looking at the RRT Connect paper notice it was done in 2000, just two years after the original RRT by the same author. The premise of this was to do a bidirectional RRT to reduce branching. It works sort of like a bidirectional BFS. On the other hand, RRT* was done in 2011, so connect has none of the reconnecting capability.

However, after trying RRT*, it might have made things worse. Some motion smoothing is needed.