How does a global planner differ from a local planner in navigation stacks?

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How does a global planner differ from a local planner in navigation stacks?

Asked on Oct 21, 2025

Answer

In robotics navigation, a global planner and a local planner serve distinct roles in path planning and execution. A global planner generates an overall path from the robot's starting position to the target destination, considering the entire environment map. In contrast, a local planner focuses on real-time adjustments and obstacle avoidance, ensuring the robot follows the global path while reacting to dynamic changes in its immediate surroundings.

Example Concept: A global planner, such as Dijkstra's or A* algorithm, calculates an optimal path based on a complete map of the environment, ensuring the path is feasible and efficient. The local planner, often using algorithms like Dynamic Window Approach (DWA) or Timed Elastic Band (TEB), refines this path by making real-time adjustments to avoid obstacles and handle dynamic environments, ensuring smooth and safe navigation.

Additional Comment:

Global planners are typically used in static environments where the map is known and does not change frequently.
Local planners are crucial in dynamic environments where obstacles can appear unexpectedly, requiring quick adjustments.
Both planners are integral parts of a navigation stack, often used in conjunction with ROS navigation frameworks.
Effective navigation requires a balance between global path efficiency and local path adaptability.

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