ROS Task by 210983

210983/Readme.md

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+ # How to Run
+
+ 1). Create a catkin workspace using **catkin_make** in a suitable directory say, catkin_ws  
+ 2). Source the setup file using **source devel/setup.bash** or **source devel/setup.zsh** depending on your terminal.  
+ 3). Copy the **math** folder into the src folder of your workspace.  
+ 4). In your workspace, build the package using **catkin_make**.  
+ 4). To run the nodes, in a new terminal run **roscore**.  
+ 5). In new terminals, run **rosrun math input_node**, **rosrun math output_node** and **rosrun math add_two_numbers_server**.  
+
+ # Steps Followed
+ 1). First created a custom msg which holds a Float64 with a header(used for Time Sync in output node) and a serivce file called add_two_numbers.srv.  
+ 2). Wrote the code for the input node in C++ which publishes two msgs to two topics(topic1 and topic2) and makes a request to the previously created service.  
+ 3). Wrote the output node to subscribe to the two topics log the sum and also publish the sum to another topic(topic3) which currently has no subscribers. I had to use **message_filters** to syncronize the messages from the two topics to use a single callback function.  
+ 4). Wrote the server for add_two_ints service.  
+ 5). Added the neccesary lines in CMakeLists.txt to make the package successfully.  

210983/src/CMakeLists.txt

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+/opt/ros/noetic/share/catkin/cmake/toplevel.cmake

210983/src/math/.vscode/c_cpp_properties.json

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+{
+  "configurations": [
+    {
+      "browse": {
+        "databaseFilename": "${default}",
+        "limitSymbolsToIncludedHeaders": false
+      },
+      "includePath": [
+        "/opt/ros/noetic/include/**",
+        "/home/shivam/ROS/Assignment1/catkin_ws/src/math/include/**",
+        "/usr/include/**"
+      ],
+      "name": "ROS",
+      "intelliSenseMode": "gcc-x64",
+      "compilerPath": "/usr/bin/gcc",
+      "cStandard": "gnu11",
+      "cppStandard": "c++14"
+    }
+  ],
+  "version": 4
+}

210983/src/math/.vscode/settings.json

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+{
+    "python.autoComplete.extraPaths": [
+        "/opt/ros/noetic/lib/python3/dist-packages"
+    ],
+    "files.associations": {
+        "array": "cpp",
+        "string": "cpp",
+        "string_view": "cpp",
+        "ratio": "cpp"
+    }
+}

210983/src/math/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.0.2)
+project(math)
+
+find_package(catkin REQUIRED COMPONENTS
+  roscpp
+  rospy
+  std_msgs
+  message_filters
+)
+
+## System dependencies are found with CMake's conventions
+find_package(catkin REQUIRED COMPONENTS 
+roscpp 
+rospy 
+std_msgs
+message_filters
+message_generation 
+genmsg)
+
+## Generate messages in the 'msg' folder
+add_message_files(
+  FILES
+  number.msg
+)
+
+## Generate services in the 'srv' folder
+add_service_files(
+  FILES
+  add_two_numbers.srv
+)
+
+## Generate actions in the 'action' folder
+# add_action_files(
+#   FILES
+#   Action1.action
+#   Action2.action
+# )
+
+## Generate added messages and services with any dependencies listed here
+generate_messages(
+  DEPENDENCIES
+  std_msgs
+  # message_filters
+)
+
+catkin_package(
+ INCLUDE_DIRS include
+ LIBRARIES math
+ CATKIN_DEPENDS roscpp rospy std_msgs message_filters message_runtime
+ DEPENDS system_lib
+)
+
+###########
+## Build ##
+###########
+
+## Specify additional locations of header files
+## Your package locations should be listed before other locations
+include_directories(
+  include
+  ${catkin_INCLUDE_DIRS}
+)
+
+add_executable(input_node src/input_node.cpp)
+target_link_libraries(input_node ${catkin_LIBRARIES})
+add_dependencies(input_node math_generate_messages_cpp)
+add_dependencies(input_node math_gencpp)
+
+
+add_executable(output_node src/output_node.cpp)
+target_link_libraries(output_node ${catkin_LIBRARIES})
+add_dependencies(output_node math_generate_messages_cpp)
+
+add_executable(add_two_numbers_server src/add_two_numbers_server.cpp)
+target_link_libraries(add_two_numbers_server ${catkin_LIBRARIES})
+add_dependencies(add_two_numbers_server math_gencpp)

210983/src/math/msg/number.msg

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+Header header
+float64 num

210983/src/math/package.xml

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+<?xml version="1.0"?>
+<package format="2">
+  <name>math</name>
+  <version>0.1.0</version>
+  <description>The math package</description>
+
+  <maintainer email="sshivam21@iitk.ac.in">shivam</maintainer>
+
+  <license>BSD</license>
+
+  <buildtool_depend>catkin</buildtool_depend>
+  <build_depend>roscpp</build_depend>
+  <build_depend>rospy</build_depend>
+  <build_depend>std_msgs</build_depend>
+  <build_depend>message_filters</build_depend>
+  <build_export_depend>roscpp</build_export_depend>
+  <build_export_depend>rospy</build_export_depend>
+  <build_export_depend>std_msgs</build_export_depend>
+  <build_export_depend>message_filters</build_export_depend>
+  <exec_depend>roscpp</exec_depend>
+  <exec_depend>rospy</exec_depend>
+  <exec_depend>std_msgs</exec_depend>
+  <exec_depend>message_filters</exec_depend>
+  <build_depend>message_generation</build_depend>
+  <exec_depend>message_runtime</exec_depend>
+
+
+  <!-- The export tag contains other, unspecified, tags -->
+  <export>
+    <!-- Other tools can request additional information be placed here -->
+
+  </export>
+</package>

210983/src/math/src/add_two_numbers_server.cpp

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+#include "ros/ros.h"
+#include "math/add_two_numbers.h"
+
+bool add(math::add_two_numbers::Request &req, math::add_two_numbers::Response &res){
+    res.sum.num = req.num1.num + req.num2.num;
+    ROS_INFO("request: x=%f, y=%f", req.num1.num, req.num2.num);
+    ROS_INFO("sending back response: [%f]", res.sum.num);
+    return true;
+}
+
+int main(int argc, char **argv){
+    ros::init(argc, argv, "add_two_numbers_server");
+    ros::NodeHandle n;
+
+    ros::ServiceServer service = n.advertiseService("add_two_numbers", add);
+    ROS_INFO("Ready to add");
+    ros::spin();
+
+    return 0;
+}

210983/src/math/src/input_node.cpp

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+#include "ros/ros.h"
+#include "std_msgs/Float64.h"
+#include "math/number.h"
+#include "math/add_two_numbers.h"
+#include<stdlib.h>
+
+using namespace math;
+
+int main(int arc, char ** argv){
+    ros::init(arc, argv, "input_node");
+    ros::NodeHandle n;
+    ros::Publisher topic1_pub = n.advertise<math::number>("topic1", 1000);
+    ros::Publisher topic2_pub = n.advertise<math::number>("topic2", 1000);
+    ros::ServiceClient client = n.serviceClient<math::add_two_numbers>("add_two_numbers");
+    math::add_two_numbers srv;
+
+    ros::Rate loop_rate(10);
+    while(ros::ok()){
+        math::number num1;
+        math::number num2;
+        num1.num = rand();
+        num2.num = rand();
+        srv.request.num1.num = num1.num;
+        srv.request.num2.num = num2.num;
+        ROS_INFO("Publishing %f to topic 1", num1.num);
+        topic1_pub.publish(num1);
+        ROS_INFO("Publishing %f to topic 2", num2.num);
+        topic2_pub.publish(num2);
+        if(client.call(srv)){
+            ROS_INFO("Sum: %f", srv.response.sum.num);
+        }
+        ros::spinOnce();
+        loop_rate.sleep();
+    }
+
+
+    return 0;
+}

210983/src/math/src/output_node.cpp

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+#include "ros/ros.h"
+#include "std_msgs/Float64.h"
+#include "math/number.h"
+#include "message_filters/subscriber.h"
+#include "message_filters/time_synchronizer.h"
+
+// using namespace message_filters;
+using namespace math;
+
+ros::Publisher topic3_pubg;
+
+void callback(const math::number::ConstPtr& num1, const math::number::ConstPtr& num2){
+    ROS_INFO("I'm publishing %f", (num1->num) + (num2->num));
+    math::number num3;
+    num3.num = (num1->num) + (num2->num);
+    topic3_pubg.publish(num3);
+}
+
+int main(int argc, char **argv){
+    ros::init(argc, argv, "output_node");
+    ros::NodeHandle n;
+    message_filters::Subscriber<math::number> topic1_sub(n, "topic1", 1);
+    message_filters::Subscriber<math::number> topic2_sub(n, "topic2", 1);
+    ros::Publisher topic3_pub = n.advertise<math::number>("topic3", 1000);
+    topic3_pubg = topic3_pub;
+    message_filters::TimeSynchronizer<math::number, math::number> sync(topic1_sub, topic2_sub, 10);
+    sync.registerCallback(boost::bind(&callback, _1, _2));
+    ros::spin();
+
+    return 0;
+}

210983/src/math/srv/add_two_numbers.srv

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+number num1
+number num2
+---
+number sum