ROS与navigation教程-Configuring Layered Costmaps

ROS与navigation教程-Configuring Layered Costmaps

说明：

• 本教程旨在指导您在代价地图中创建自定义的一组图层。

• This will be accomplished using the costmap_2d_node executable, although the parameters can be ported into move_base.

Step 1: Transforms

• One basic thing that the costmap requires is a transformation from the frame of the costmap to the frame of the robot. For this purpose, one solution is to create a static transform publisher in a launch file.

    <node name="static_tf0" pkg="tf" type="static_transform_publisher" args="2 0 0 0 0 0 /map /base_link 100"/>

Step 2: Basic Parameters

• 接下来，需要指定costmap的行为。

• 创建一个将被加载到参数空间中的minimal.yaml文件。

plugins: []
publish_frequency: 1.0
footprint: [[-0.325, -0.325], [-0.325, 0.325], [0.325, 0.325], [0.46, 0.0], [0.325, -0.325]]

• We start out with no layers for simplicity.

• 为了方便进行调试，publish_frequency为1.0Hz，我们指定了一个简单的脚本，因为costmap需要定义一些footprint。

• 这些参数可以通过配置以下启动文件来加载

<rosparam file="$(find simple_costmap_configuration)/params/minimal.yaml" command="load" ns="/costmap_node/costmap" />

• 注意：如果您在没有插件参数的情况下运行costmap，则将采用预先配置的参数配置方式，并根据使用的代价地图自动创建图层。

Step 3: Plugins Specification

• 如果要指定图层，其需要将字典存储在插件数组中。 例如：

plugins: 
- {name: static_map,       type: "costmap_2d::StaticLayer"}

• 假设要发布一个类似以下内容的静态地图。

    <node name="map_server" pkg="map_server" type="map_server" args="$(find simple_costmap_configuration)/realmap.yaml"/>

• 可以在数组中添加额外的字典。

plugins: 
- {name: static_map,       type: "costmap_2d::StaticLayer"}
- {name: obstacles,        type: "costmap_2d::VoxelLayer"}

• The namespace for each of the layers is one level down from where the plugins are specified.

• 因此，需要扩展参数文件来指定障碍层的内容。

plugins: 
- {name: static_map,       type: "costmap_2d::StaticLayer"}
- {name: obstacles,        type: "costmap_2d::VoxelLayer"}
publish_frequency: 1.0
obstacles:
observation_sources: base_scan
base_scan: {data_type: LaserScan, sensor_frame: /base_laser_link,  clearing: true, marking: true, topic: /base_scan}

参考资料

• wiki.ros.org/costmap_2d/Tutorials/Configuring Layered Costmaps#Step_2:_Basic_Parameters