Rename possible_inscribed_cost into possible_circumscribed_cost in collision_checker.setFootprint

[alanxuefei]

Bug report

The name of possible_inscribed_cost in GridCollisionChecker::setFootprint may not be accurate.

void GridCollisionChecker::setFootprint(
  const nav2_costmap_2d::Footprint & footprint,
  const bool & radius,
  const double & possible_inscribed_cost)

Because nav2_smac_planner and smac_planner_lattice use circumscribed radius cost (outside circle) instead of inscribed radius cost (inside circle).

  _collision_checker.setFootprint(
    _costmap_ros->getRobotFootprint(),
    _costmap_ros->getUseRadius(),
    findCircumscribedCost(_costmap_ros));

Inscribed radius (inside circle) may not be sufficient for conduct collision check.

Should I create a PR to fix it?

[SteveMacenski]

I agree perhaps it could be renamed more clearly. possible_collision_cost?

We use the circumscribed radius as a check to see if its possible that any point on the robot might be in collision. I agree inscribed is an odd choice when I wrote that. We should update MPPI's Cost and Obstacle critics' variables of similar use while we're at it!

[alanxuefei]

I will create a PR within this week.