Abdur Rosyid's Blog
Just a few notes on mechanical engineering and robotics
tf Broadcaster and Listener tf broadcaster node written in C++ can be found here: In the code above, the node is subscribing to the pose of robot given by “turtle_name” parameter. Upon receiving the pose topic, it will run “poseCallback” callback function which basically broadcast the transformation between the robot frame and the world frame. …
tf Broadcaster and Listener tf broadcaster node written in Python can be found here: In the code above, the node is subscribing to the pose of robot given by “~turtle” parameter. Upon receiving the pose topic, it will run “handle_turtle_pose” callback function which basically broadcast the transformation between the robot frame and the world frame. …
tf and tf2 are ROS packages that handles frame transformation in the time frame. This means, we can get information about “What is the relative pose of Frame B with respect to Frame A at 10 seconds ago.” Frame transformation is extremely important in robotics as a robot itself typically consist of several frames, such …
The URDF robot description can be used to simulate the robot in Gazebo. This can be done through the following steps. For the example below, the folders “urdf”, “config”, “rviz”, and “launch” used in the example are all inside “my_robot_description” package. Step 1: Install gazebo_ros_pkgs package which connect between Gazebo and ROS. Step 2: Install …
xacro is a language defined in ROS to be used to: simplify URDF; make URDF cleaner make it easier to change the URDF’s parameters create a modular URDF xacro:property Use case 1: Using xacro:property, we can use constants as variables so that it is easier to change them or to avoid redundancy (repetition) in their …
URDF is the description of your robot. It describes how your robot looks like (the number of links, properties of the links, types of joints, where the joints located, properties of the joints, etc) and how the links of the robot move relative to each other. The kinematics of your robot is based on the …
The following are some differences between ROS1 and ROS2. Difference 1: Master-Slave vs Distributed Network Architecture ROS1 communication is based on TCPROS (a custom TCP communication) with master-slave network architecture, where one computer/robot should serve as ROS Master while the others serve as slaves. If ROS Master fails, the whole network fails. ROS2 is based …
Below are the steps to create a ROS2 action using Python. Notice that we are going to have two packages involved: 1) a package called “my_package” which contains the action file, and 2) a package called “action_nodes_python” which contains the action server and client nodes. Separating the package which contains the action file(s) like this, …
Below are the steps to create a ROS2 action. Notice that we are going to have two packages involved: 1) a package called “my_package” which contains the action file, and 2) a package called “action_nodes_cpp” which contains the action server and client nodes. Separating the package which contains the action file(s) like this, in general, …
In ROS1, we write a launch file in XML. In ROS2, there are three ways to write a launch file: Using Python Using XML Using YAML Since the API of ROS2 launch is written in Python, you have a lower level access to the launch features if you write your launch file in Python. This …