3️⃣Hardware Integration
Launch the robot's motor and sensor drivers.
Run
rosnode list
to find the names of the ROS nodes of the drivers.Run
rosnode info <node>
, where <node> is the name of the nodes determined from step 2. Sample output:$ rosnode info /motors_ctrl -------------------------------------------------------------------------------- Node [/motors_ctrl] Publications: * /odom [nav_msgs/Odometry] * /odom_euler [std_msgs/String] * /robot_batt_perc [std_msgs/Int16] * /rosout [rosgraph_msgs/Log] * /tf [tf2_msgs/TFMessage] Subscriptions: * /cmd_vel [geometry_msgs/Twist]
From the information displayed from running step 3, make sure that:
The robot motor driver node subscribes to the topic
/cmd_vel
for velocity commands.The Lidar driver node publishes laser data to the topic
/scan
If the topic names are not set as in step 4, remap them in the launch files of the drivers by adding a line in the launch files in the following format:
<node ... <remap from="<original topic name>" to="/cmd_vel"/> </node>
While the robot base and lidar are launched, run
rosrun rqt_tf_tree rqt_tf_tree
and check that the frames are linked in this order: odom → base_link → laser.If the frames of base_link and laser are not linked correctly, there are two options you can link them. You can select one of them. (Prefer use Broadcast a transformation)
Broadcast a transformation refer to this link.
Create static transformation. Add the following line in the launch file of the lidar drivers:
<node pkg="tf" type="static_transform_publisher" name="base_link_to_laser" args="0.22 0 0.1397 0 0 0 base_link laser 100" />
In “args”, x = 0.22, y = 0, z = 0.1397, yaw = 0, pitch = 0, roll = 0 for this example. This should provide a transformation between the base_link and laser frame If you use static transformation, there will be several issues, one of the most is localizer mode, the UI won't visualize a laser scan in localizer mode.
With the driver nodes running, run RVIZ using:
rosrun rviz rviz
, do the following checks:Laser data
("/scan")
can be seen and is orientated in the correct direction.Movement direction during teleoperation is correct.
Robot odometry
("/odom")
is updating correctly during teleoperation.
Last updated
Was this helpful?