The Nav2 Controller is a Task Server in Nav2 that implements the nav2_msgs::action::FollowPath action server.
An execution module implementing the nav2_msgs::action::FollowPath action server is responsible for generating command velocities for the robot, given the computed path from the planner module in nav2_planner. The nav2_controller package is designed to be loaded with multiple plugins for path execution. The plugins need to implement functions in the virtual base class defined in the controller header file in nav2_core package. It also contains progress checkers and goal checker plugins to abstract out that logic from specific controller implementations.
See the Navigation Plugin list for a list of the currently known and available controller plugins.
See its Configuration Guide Page for additional parameter descriptions and a tutorial about writing controller plugins.
The ControllerServer makes use of a nav2_util::TwistPublisher.