Morphin has the ability to recommend good steering commands to the arbiter, and also vetoes dangerous commands.|
Steering can be either left or right, over a range of turn radii. The
range of radii is discretized to form about twenty possible steering
commands. Each such command corresponds to a steering arc, calculated
by propagating the rover pose forward in time with that command in
Morphin evaluates each arc based on the average traversability and
certainty of grid cells along the arc, and the worst hazard encountered
on the arc. It uses these data to calculate a figure called merit.
Morphin recommends high merit steering commands to the arbiter, and
vetoes commands below a certain threshold as unsafe.
In the Morphin map shown above, the blue arcs are steering arcs under
evaluation. In this case, Morphin will recommend that the vehicle make
a left turn in order to travel through high-certainty, safe terrain.
Although Morphin is myopic and has no notion of a goal position, it
complements a global path planner with the following advantages:
- It requires little computational power, and can operate at high
resolution and high frequency.
- It does not make any assumptions about the robot having holonomic
motion or omni-directional sensing.