Indoor ROS robot navigation commissioning record (experience in selecting expansion radius)

1. map layer

notes : In the diagram above , The red part represents the obstacles in the cost map , The blue part represents the obstacle with the expansion of the robot's inscribed radius , The red polygon represents the boundary of the robot (footprint). In order to make the robot avoid collision , The red boundary of the robot cannot intersect with the red part , The center point of the robot cannot intersect with the blue part .

Suppose there is a circular robot with a radius of 0.5m, that

Expansion radius , The expansion layer will expand the obstacle until the radius , Generally, this value is set to the diameter of the robot chassis .

problem 1： Theoretically , The minimum expansion radius is the radius of the robot , Otherwise, it is easy to hit obstacles ？ For example, the radius is 0.5m Robot , Whether the global expansion radius can be set as 0.5 A slightly larger value , for example 0.8m? [ To be verified ]

2. Common cost map layers

Static map layer ： Basically unchanged layer , Usually SLAM Build a static map
Obstacle map layer ： It is used to dynamically record the obstacle information perceived by the sensor
Expansive layer ： Expand on the static map and obstacle map layers （ Expand outward ）, To avoid the robot hitting obstacles
Other layers ： Other map layers implemented through plug-ins , For example, sensor map layer

3. Experience summary of expansion radius test

The expansion radius setting is too small , There may be movement against obstacles . The radius is 0.25m Robot , Set to 0.6m There will be obvious movement against obstacles , Set to 0.8m More appropriate .

The actual size of the robot is very important , Write the actual measurement , You can't write the size larger . The measured found , Actual radius of robot 0.254m, It has been written. 0.27m（ The idea was , Write the radius larger , Avoid hitting obstacles ）, The test results were found to be 0.27m, Global expansion radius 1.1m, Local expansion radius 0.1m, too 80cm Narrow road of , More difficult （ Setting the transition point is not enough ）. But change to the actual radius of the robot , Normal navigation can also be through 80cm Narrow road of .

Tests found , The global expansion radius has little effect on the robot passing through narrow roads , Pay more attention to the actual size and local expansion radius parameters when passing through narrow roads .

Reference link ：
costmap_2d-ROS Wiki