A simple tool to split the lidar data into multiple areas, just like multiple ultrasonic sensors
Author: Sunshengjin @MindPointEye [email protected]
Because the ultrasonic sensor is not so reliable, and in the mobile robot or some area protection tasks, it is necessary to detect and warn the obstacles in a specific range or area, so i made this small tool and used the reliable data of the lidar to be divided into multiple programmable areas to detect obstacles.
Recommended system environment: Ubuntu16.04 + ROS Kinetic
- Note:It not rely heavily on a specific system environment, It can also run smoothly on other system versions, Such as Ubuntu14.04 + ROS Indigo.
Copy this package into your {ros_workspace}/src
$ cd catkin_workspace/src
$ git clone https://github.com/Sunshengjin/lidar_obstacle_avoidance.git
$ cd ../
Compile your ros workspace
$ catkin_make
$ rospack profile
Please run your lidar driver node Note:Make sure your lidar publish topic is as seem as the topic setting which in the demo.launch.
Then you can run this tool:
$ roslaunch lidar_obstacle_avoidance demo.launch
This tools just subscribe the lidar scan topic ,and it will publish several topic based on the number you set the areas. The configuration file is {ros_workspace}/src/lidar_obstacle_avoidance/launch/demo.launch.
demo.launch
<arg name="Pi" value="3.1415926"/>
<node name="loa_node" pkg="lidar_obstacle_avoidance" type="loa_node" output="screen" respawn="true">
<param name="scan_topic" type="string" value="/scan"/>
<param name="num_of_area" type="int" value="5"/>
<param name="area_1_min_ang" type="double" value="-90"/>
<param name="area_1_max_ang" type="double" value="-60"/>
<param name="area_1_max_range" type="double" value="3"/>
<param name="area_1_min_range" type="double" value="1"/>
<param name="area_1_filter_size" type="int" value="3"/>
<param name="area_2_min_ang" type="double" value="-50"/>
<param name="area_2_max_ang" type="double" value="-20"/>
<param name="area_2_max_range" type="double" value="3"/>
<param name="area_2_min_range" type="double" value="1"/>
<param name="area_2_filter_size" type="int" value="3"/>
<param name="area_3_min_ang" type="double" value="-10"/>
<param name="area_3_max_ang" type="double" value="20"/>
<param name="area_3_max_range" type="double" value="3"/>
<param name="area_3_min_range" type="double" value="1"/>
<param name="area_3_filter_size" type="int" value="3"/>
<param name="area_4_min_ang" type="double" value="30"/>
<param name="area_4_max_ang" type="double" value="50"/>
<param name="area_4_max_range" type="double" value="3"/>
<param name="area_4_min_range" type="double" value="1"/>
<param name="area_4_filter_size" type="int" value="3"/>
<param name="area_5_min_ang" type="double" value="60"/>
<param name="area_5_max_ang" type="double" value="90"/>
<param name="area_5_max_range" type="double" value="3"/>
<param name="area_5_min_range" type="double" value="1"/>
<param name="area_5_filter_size" type="int" value="3"/>
</node>
<!--ang to rad :rad = PI/180 * ang -->
<!--How to calculat the Yaw set -->
<!-- Yaw = (max_ang + min_ang)/2 * (PI / 180) -->
<node pkg="tf" type="static_transform_publisher" name="lidar_to_range1" args="0.0 0.0 0.0 -1.309 0.0 0.0 /laser /range1 40"/>
<node pkg="tf" type="static_transform_publisher" name="lidar_to_range2" args="0.0 0.0 0.0 -0.611 0.0 0.0 /laser /range2 40"/>
<node pkg="tf" type="static_transform_publisher" name="lidar_to_range3" args="0.0 0.0 0.0 0.0872 0.0 0.0 /laser /range3 40"/>
<node pkg="tf" type="static_transform_publisher" name="lidar_to_range4" args="0.0 0.0 0.0 0.698 0.0 0.0 /laser /range4 40"/>
<node pkg="tf" type="static_transform_publisher" name="lidar_to_range5" args="0.0 0.0 0.0 1.309 0.0 0.0 /laser /range5 40"/>
</launch>
If you want to change the configuration to what you need,just follow the steps below:
Step 1
Make sure your lidar publish topic is as seem as the topic setting which in the demo.launch.
<param name="scan_topic" type="string" value="/scan"/>
Step 2
Set the number of the defence area.
<param name="num_of_area" type="int" value="5"/>
Step 3
Set parameters for each area.
example:
<param name="area_1_min_ang" type="double" value="-90"/>
<param name="area_1_max_ang" type="double" value="-60"/>
<param name="area_1_max_range" type="double" value="3"/>
<param name="area_1_min_range" type="double" value="1"/>
<param name="area_1_filter_size" type="int" value="3"/>
- min_ang : start angle of the area [ang]
- max_ang : end angle of the area [ang]
- max_range : maximum range value [m]
- min_range : minimum range value [m]
- filter_size : The size of the data filter.If the number of obstacle sampling points is less than the set value,this data will be ignored.
Step 4
Set the transform tree for each area
example:
<node pkg="tf" type="static_transform_publisher" name="lidar_to_range1" args="0.0 0.0 0.0 -1.309 0.0 0.0 /laser /range1 40"/>
Note:you only need to set the 4th parameter of the args tags,you need to manually calculate the value of this parameter yourself. The calculation formula is {Yaw = (max_ang + min_ang)/2 * (PI / 180)}
Step 5
Now you can run this tools ,and you can subscribe the range topic : /rangeX (X is which of the area range data you want to get).
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