ros_gmapping_movebase

This ROS package provides three behaviors for controlling a simulated mobile robot using gmapping and movebase rospackages. You can get to know more about the detatils of the source code using the documentation provided for this rospackage.

Installing and runnning

Here is the instruction for using the package:

$ mkdir -p catkin_ws/src

$ cd catkin_ws/src

$ git clone https://github.com/aliy98/ros_gmapping_movebase

$ cd ..

$ source /opt/ros/<distro>/setup.bash

$ catkin_make

$ source devel/setup.bash

$ sudo apt install konsole

$ roslaunch final_assignment simulation_gmapping.launch

in order to run the movebase node, open a new terminal in the same directory and run the following commands:

$ source devel/setup.bash

$ roslaunch final_assignment move_base.launch

For initializing the master node also, in a new terminal run the following commands:

$ source devel/setup.bash

$ roslaunch final_assignment master.launch

then you can choose robot's behaviour by inputing the corresponding number

Software Architecture

Software architecture in this project is based on three nodes:

1. Master Node: gets user request to choose robot behaviour using robot_state rosparam
2. Movebase Client Node: gets desired position from user and sends it to movebase node using actionlib and if the goal is not reached before timeout cancels it
3. Teleop Twist Keyboard Node: it can implement two behaviours on robot: 1: moving without obstacle avoidance: user can move the robot using keys it publishes the desired movements to cmd_vel topic 2: moveing with obstacle avoidance: subscribes scan topic and uses it to detect obstacles. user can move the robot using keys and it also avoids the robot from colliding the obstacles

Pseudocode

***
  master node:
  
  main()
  {
        set the initial state of robot_state rosparam as 0 (master node)
        initialize the master node
        while (1)
        {
              if robot_state is 0 (master node)
              {
                    get user request for selecting the robot behaviour
                    set robot_state rosparam as the chosen robot behaviour to enable the corresponding node
              } 
              else 
              {
                    wait for other nodes' response 
              }
        }
  }

  
***
  movebase client node:
  
  main()
  {
        initialize movebase client node
        while(1)
        {
              get robot_state rosparam to detect user choice
              if robot_state is 1 (movebase_client node)
              {
                    get target point from user
                    call movebase node to send target point as an action 
                    detect if the target has been reached before timeout
              } 
              else 
              {
                    wait for master node's response
              }
        }
  }

***
  teleop twist keyboard node:
  
  main()
  {
        initialize teleop twist keyboard node
        while(1)
        {
              get robot_state rosparam to detect user choice
              if robot_state is 2 (manual teleop twist keyboard)
              {
                    get user command for moving the robot
                    publish the corresponding twist to cmd_vel topic
              } 
              else if  robot_state is 3 (assisted teleop twist keyboard)
              {
                    subscribe laser scan topic to detect obstacles
                    get user command for moving the robot
                    if there is an obstacle 
                    {
                          don't move the robot toward it
                    } 
                    else 
                    {
                          publish the corresponding twist to cmd_vel topic
                    }
              } 
              else 
              {
                    wait for master node's response
              }
        }
  }