rotation-shim-controller

To rotate a differential-drive robot in place before path following in ROS 2 navigation, you can use a rotation shim controller. It aligns the robot's heading with the new path direction at the start of a navigation goal before handing off to your primary controller.

Your robot attempts path following before facing the right direction due to misalignment between its heading and the path's starting orientation. An in-place rotation controller resolves this by first rotating the robot to align with the path trajectory.

Yes, you can use a rotation shim with MPPI, DWB, or RPP controllers in ROS 2. The shim wraps around your chosen primary controller, performing the initial in-place rotation and then transferring control to the primary controller for path following.

To configure in-place rotation, you set parameters like angular_dist_threshold, forward_sampling_distance, and simulate_ahead_time. The controller uses these values to define rotation limits and runs a collision-check loop during the alignment process.

The best way to ensure smooth navigation startup when a new path faces a different direction is applying an initial in-place rotation. This guarantees safe, aligned startup on differential-drive robots before the primary path following controller engages.

Yes, in-place rotation during ROS 2 navigation goals checks for obstacles. The rotation controller includes a built-in collision-check loop that monitors the environment while the robot performs the initial alignment rotation.