Path planning

A set of path planners for robots operating in planar environments with configuration \(\vec{q} \in \mathbb{R}^2\) or \(\vec{q} \in \mathbb{R}^2 \times S^1 \sim \SE{2}\). All inherit from PlannerBase.

Some planners are based on code from the PathPlanning category of PythonRobotics by Atsushi Sakai.

Planner	Plans in	Discrete/Continuous	Obstacle avoidance
`Bug2`	\(\mathbb{R}^2\)	discrete	yes
`DistanceTransformPlanner`	\(\mathbb{R}^2\)	discrete	yes
`DstarPlanner`	\(\mathbb{R}^2\)	discrete	yes
`PRMPlanner`	\(\mathbb{R}^2\)	continuous	yes
`LatticePlanner`	\(\SE{2}\)	discrete	yes
`DubinsPlanner`	\(\SE{2}\)	continuous	no
`ReedsSheppPlanner`	\(\SE{2}\)	continuous	no
`CurvaturePolyPlanner`	\(\SE{2}\)	continuous	no
`QuinticPolyPlanner`	\(\SE{2}\)	continuous	no
`RRTPlanner`	\(\SE{2}\)	continuous	yes

Using a planner

The planners do not share one call signature, because the algorithms need different things at different times. They fall into four families, and the verbs a planner has are the ones that make sense for it.

Family	Planners	`plan`	`query` or `run`
Plan for a goal, then query many starts	`DistanceTransformPlanner`, `DstarPlanner`, `RRTPlanner`	`plan(goal)`	`query(start)`, Dstar also takes a `sensor` function
Build a map of the space, then query both ends	`PRMPlanner`, `LatticePlanner`	`plan(npoints)` or `plan(iterations)`	`query(start, goal)`
Nothing to plan	`DubinsPlanner`, `ReedsSheppPlanner`, `QuinticPolyPlanner`, `CurvaturePolyPlanner`	none	`query(start, goal)`
Reactive	`Bug2`	none	`run(start, goal)`

Failure

ValueError: the arguments are invalid, for example the start is inside an obstacle or has the wrong length.
NoPathError: the problem is valid but has no solution, for example the goal is unreachable or the robot is trapped. It is a RuntimeError.
RuntimeError: query was called before plan.

Animation

Planners that can animate take animate and movie arguments at the constructor, which set the default for the planner and can be overridden by the same arguments of the method that runs the animation. A movie implies animate.