Recommended approach for stair climbing with a quadruped in Nav2

[BryanBetancur]

Hello,

I’m working with a quadruped robot and would like some guidance on the recommended way to handle stairs and ramps using Nav2.

Since Nav2 is mainly 2D costmap–based, stairs are typically treated as obstacles for wheeled robots. However, for a quadruped, stairs and ramps can be traversable, while drop-offs / negative obstacles must be avoided.

Context:

Robot: Quadruped

Sensors: 3D perception (LiDAR / depth)

Optional: high-quality static 3D map (LAS) as a prior

Navigation: Nav2 (ROS 2 humble)

Questions:

• Is the recommended approach to model stairs as high-cost traversable areas instead of lethal obstacles?

• Would using a 2.5D elevation / traversability map upstream and feeding Nav2 a derived costmap be the right direction?

• How can the local costmap be prevented from invalidating valid global paths through stairs?

Thanks for any guidance or references.

[SteveMacenski]

Usually there are stairclimbing behaviors of quadrupeds from the manufacturer that you should leverage. When using its own vision, then the costmaps don't matter since you can engage that behavior from the behavior tree independent from the costmap. I believe most if not all quadupeds on the market now generate their own local risk maps for use in their aided-teleop / stairclimbing behaviors (which also may be good to add into your costmap, depending on how much you trust its built-in sensors).