refactor: Modify the readme

Signed-off-by: Tony Zhang <hitxfd.tony@gmail.com>

readme.md

@@ -4,7 +4,7 @@
 (3) Please also install libpcap-dev.
 
 ####  2. Install
-(1). Copy the whole rslidar directory into ROS workspace, i.e "~/catkin_ws/src".
+(1). Copy the whole rslidar ROS driver directory into ROS workspace, i.e "~/catkin_ws/src".
 
 (2). Check the file attributes:
 
@@ -22,10 +22,10 @@ cd ~/catkin_ws
 catkin_make
 ```
 #### 3. Configure PC IP
-By default, the RSLIDAR is configured to **192.168.1.200** as its device IP and **192.168.1.102** as PC IP that it would communicate. The default MSOP port is 6699.
+By default, the RSLIDAR is configured to **192.168.1.200** as its device IP and **192.168.1.102** as PC IP that it would communicate. The default **MSOP port is 6699** while **DIFOP port is 7788**.
 So you need configure your PC IP as a static one **192.168.1.102**.
 
-#### 4. Run and view real time data
+#### 4. Run as independent node
 We have provide example launch files under rslidar_pointcloud/launch, we can run the launch file to view the point cloud data. For example, if we want to view RS-LiDAR-16 real time data:
 (1). Open a new terminal and run:
 
@@ -43,10 +43,25 @@ rviz
 Set the Fixed Frame to "**rslidar**".
 Add a Pointcloud2 type and set the topic to "**rslidar_points**".
 
-#### 5. About the lidar data
-Under "**rslidar_pointcloud/data**" directory, you can find the lidar data files for the exact sensor. By default the launch file "rs_lidar_16.launch" load the three files:
+#### 5. Run as nodelet
+We can also run the driver node and cloud node as a nodelet.
+Open a new terminal and run:
+
+```
+cd ~/catkin_ws
+source devel/setup.bash
+roslaunch rslidar_pointcloud cloud_nodelet.launch
+```
+Then we can run view the pointcloud via "rviz"
+
+#### 6. About the lidar calibration parameters
+Under "**rslidar_pointcloud/data**" directory, you can find the lidar calibration parameters files for the exact sensor. By default the launch file "rs_lidar_16.launch" load the three files:
 - rslidar_pointcloud/data/rs_lidar_16/angle.csv
 - rslidar_pointcloud/data/rs_lidar_16/ChannelNum.csv
 - rslidar_pointcloud/data/rs_lidar_16/curves.csv.
 
 If you have more than one RSLIDAR, you can create new sub-directories under the "**rslidar_pointcloud/data/**", and put the data files into it.Then you need rewrite the launch file to start you lidar. We have put an example launch file "two_lidar.launch" to load two lidars together for reference.
+
+**Begin from 2018.09.01**
+In the launch file, we could set the MSOP port and DIFOP port.
+MSOP port is used for receive the main point cloud data, while DIFOP port is used for receive the device information data. If we set the right DIFOP port, we will get the lidar calibration parameters from the DIFOP packets not from the files, so can ignore the local lidar calibration files. About how to check the DIFOP port, please reference the Appendix G in RS-LiDARR manual.

rslidar_pointcloud/launch/rs_lidar_16.launch

@@ -1,18 +1,23 @@
 <launch>
+  <arg name="model" default="RS16" />
+  <arg name="device_ip" default="192.168.1.200" />
+  <arg name="msop_port" default="6699" />
+  <arg name="difop_port" default="7788" />
+  <arg name="lidar_param_path" default="$(find rslidar_pointcloud)/data/rs_lidar_16/"/>
+
   <node  name="rslidar_node" pkg="rslidar_driver" type="rslidar_node" output="screen" >
-    <param name="model" value="RS16"/>
+    <param name="model" value="$(arg model)"/>
+    <param name="device_ip" value="$(arg device_ip)" />
+    <param name="msop_port" value="$(arg msop_port)" />
+    <param name="difop_port" value="$(arg difop_port)"/>
     <!--param name="pcap" value="path_to_pcap"/-->
-    <param name="device_ip" value="192.168.1.200"/>
-    <!-- Set the Lidar data port on the PC side, default is 6699 -->
-    <param name="msop_port" value="6699"/>
-    <param name="difop_port" value="7788"/>
   </node>
 
   <node  name="cloud_node" pkg="rslidar_pointcloud" type="cloud_node" output="screen" >
-    <param name="model" value="RS16"/>
-    <param name="curves_path" value="$(find rslidar_pointcloud)/data/rs_lidar_16/curves.csv" />
-    <param name="angle_path" value="$(find rslidar_pointcloud)/data/rs_lidar_16/angle.csv" />
-    <param name="channel_path" value="$(find rslidar_pointcloud)/data/rs_lidar_16/ChannelNum.csv" />
+    <param name="model" value="$(arg model)"/>
+    <param name="curves_path" value="$(arg lidar_param_path)/curves.csv" />
+    <param name="angle_path" value="$(arg lidar_param_path)/angle.csv" />
+    <param name="channel_path" value="$(arg lidar_param_path)/ChannelNum.csv" />
   </node>
 
   <node name="rviz" pkg="rviz" type="rviz"  args="-d $(find rslidar_pointcloud)/rviz_cfg/rslidar.rviz" />

rslidar_pointcloud/launch/rs_lidar_32.launch

@@ -1,18 +1,24 @@
 <launch>
+  <arg name="model" default="RS32" />
+  <arg name="device_ip" default="192.168.1.200" />
+  <arg name="msop_port" default="6699" />
+  <arg name="difop_port" default="7788" />
+  <arg name="lidar_param_path" default="$(find rslidar_pointcloud)/data/rs_lidar_32/"/>
+
   <node  name="rslidar_node" pkg="rslidar_driver" type="rslidar_node" output="screen" >
-    <param name="model" value="RS32"/>
+    <param name="model" value="$(arg model)"/>
+    <param name="device_ip" value="$(arg device_ip)" />
+    <param name="msop_port" value="$(arg msop_port)" />
+    <param name="difop_port" value="$(arg difop_port)"/>
     <!--param name="pcap" value="path_to_pcap"/-->
-    <!--param name="device_ip" value="192.168.1.200"/-->
-    <!-- Set the Lidar data port on the PC side, default is 6699 -->
-    <param name="msop_port" value="6699"/>
   </node>
 
   <node  name="cloud_node" pkg="rslidar_pointcloud" type="cloud_node" output="screen" >
-    <param name="model" value="RS32"/>
-    <param name="curves_path" value="$(find rslidar_pointcloud)/data/rs_lidar_32/curves.csv" />
-    <param name="angle_path" value="$(find rslidar_pointcloud)/data/rs_lidar_32/angle.csv" />
-    <param name="channel_path" value="$(find rslidar_pointcloud)/data/rs_lidar_32/ChannelNum.csv" />
-    <param name="curves_rate_path" value="$(find rslidar_pointcloud)/data/rs_lidar_32/CurveRate.csv" />
+    <param name="model" value="$(arg model)"/>
+    <param name="curves_path" value="$(arg lidar_param_path)/curves.csv" />
+    <param name="angle_path" value="$(arg lidar_param_path)/angle.csv" />
+    <param name="channel_path" value="$(arg lidar_param_path)/ChannelNum.csv" />
+    <param name="curves_rate_path" value="$(arg lidar_param_path)/CurveRate.csv" />
   </node>
 
   <node name="rviz" pkg="rviz" type="rviz"  args="-d $(find rslidar_pointcloud)/rviz_cfg/rslidar.rviz" />