Implementation of ROS to receive and process information from several sensors and send orders to actuators.
To communicate the control messages it uses a geometry_msgs::Twist format as the following:
This node was made for [ROS Kinetic](ROS Kinetic), and tested in an environment using gcc (Ubuntu 5.4.0-6ubuntu1~16.04.9).
In order to build the executable node the next steps are suggested:
- Make the root folder miniROSCar a catkin workspace,
- Go to the miniROSCar and execute
catkin_make
- Go to the miniROSCar and execute
- Wait until the building process is finished and execute
source devel/setup.bashnow the node is ready to run.
The standard notation package and node is enough to run the node...
roscorerosrun kontrollieren kontrol_trajectory_node
The node subscribes to three signals from different sensors, thanks to the wrapping facilities of ROS it's just a matter of asking to the correct topics. Wich in this case will be three:
- "/turtle1/cmd_vel" (geometry_msgs::Twist robot_position)
- This one is special, it's a node from the turtle sim package which listens to a given input on the keyboard.
- "/ultrasound" (sensor_msgs::Range robot_positionRange)
- "/imu" (sensor_msgs::Imu robot_positionImu)
The node publishes the control signals (which go direct into another node inside an arduino to control two actuators in a little car).
- geometry_msgs::Twist command_msg (geometry_msgs::Twist in the topic "/kontrolliert")
The format of the control signal is the following:
For geometry_msgs::Twist using:
dummy.linear.x
dummy.linear.y
dummy.angular.z
The node frome turtlesim needed is:
rosrun turtlesim turtle_teleop_key
To change the "mode of operation" of the car (from manual control to following and object) is:
rostopic pub /turtle1/cmd_vel geometry_msgs/Twist '[0.0, 1.0, 0.0]' '[0.0, 0.0, 0.0]'