Navigating tight spaces

The focus of any motion planner is collision detection and avoidance. Hence, the precision of the generated safe paths is a very important factor.

The PRM planner relies on the random points it placed during the mapping phase. If the random points do not land inside a narrow space, the robot will think it is blocked, even if there is plenty of room. A larger Number of samples and more Edges per sample will produce a finer-grained roadmap which will take longer to generate, but will lead to a more precise solution.

Smart Motion includes a Constrained Space option for such tricky spots. When this is on, the solver is forced to operate in joint space rather than cartesian space. By doing so, it ensures that when a pose is tested, the system identifies a unique joint configuration, which prevents issues related to multiple possible solutions for a single cartesian pose. In short, this helps the planner remember the robot's position and configuration to ensure the found path is preserved.