Abdur Rosyid's Blog
Just a few notes on mechanical engineering and robotics
Different from ROS service which consists of request and response only, ROS action additionally provides feedback. An action consists off three main parts: request, feedback, and result (which is similar to response in service). While a service is appropriate to be used for a non-progressive task, an action is appropriate to be used for a …
The following are some steps to create a ROS1 service in Python: Step 1: Add the following in package.xml rospy std_msgs message_generation rospy std_msgs message_runtime Step 2: Add the following in CMakeLists.txt find_package(catkin REQUIRED COMPONENTS message_generation std_msgs rospy) add_service_files(FILES ServiceName.srv) generate_messages(DEPENDENCIES std_msgs) catkin_package( LIBRARIES package_name CATKIN_DEPENDS std_msgs rospy ) catkin_install_python(PROGRAMS script/service_server.py DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION} ) catkin_install_python(PROGRAMS …
The following are some steps to create a ROS1 service in C++: Step 1: Add the following in package.xml roscpp std_msgs message_generation roscpp std_msgs message_runtime Step 2: Add the following in CMakeLists.txt find_package(catkin REQUIRED COMPONENTS message_generation std_msgs roscpp) add_service_files(FILES ServiceName.srv) generate_messages(DEPENDENCIES std_msgs) catkin_package( LIBRARIES package_name CATKIN_DEPENDS std_msgs roscpp ) include_directories(${catkin_INCLUDE_DIRS}) add_executable(service_server src/service_server.cpp) add_dependencies(service_server ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS}) …
Different from topic, service is bidirectional communication between a service server and a service client. The service can be described as the following sequential mechanism: A service client makes a request to a service server The service server sends a response to the service client The communication between the service client and the service server …
In ROS, a node can publish a topic and subscribe (listen) to a topic. A topic is basically a unidirectional message in a certain data type containing some information. It is like a radio broadcast. The radio station is the topic publisher whereas the radio receiver is the topic subscriber. The topic is the radio …
A ROS package is a wrapper or container of a piece of code. By this definition, you can write any C++ or Python code and then wrap it in a ROS package in order to use it in ROS. There are two types of packages in ROS: 1) packages already built in ROS and 2) …
In ROS1, one machine/robot should serve as ROS Master whereas all the other machines/robots/devices in the same ROS network serve as ROS Clients. ROS Master can be a computer or a robot. The ROS Client can be a computer, a robot, or a device. The following is some steps to setup ROS1 network between multiple …
It is recommended to install an LTS ROS distribution, which is always to be installed on a certain LTS distribution of Linux Ubuntu. A specific ROS distribution can only be installed on a specific Linux Ubuntu distribution. ROS can be installed from either source or from binary (Debian installer). It is recommended to install the …
Based on my experience, here I summarize what to learn in Robot Operating System (ROS): 1 How to install ROS and prepare your development environment 2 How to create a ROS package and build it in your workspace 3 How to establish a ROS network between multiple machines and devices 4 Message communication in ROS: …
The main aspects of robotics can be summarized below: 1. Topology There are so many existing and possible-in-the-future body types and topologies of a robot. The existing ones include: 1) wheeled unmanned ground vehicles (UGVs), 2) track-chained UGVs, 3) biped, quadruped, and six-legged robots, 4) humanoids, 5) multi-rotor unmanned aerial vehicles (UAVs), 6) flapping aerial …