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A* ALGORITHM BASICS FOR PATH FINDING & HEURISTICS METHODS : ARTIFICIAL INTELLIGENCE

 A* ALGORITHM BASICS FOR PATH FINDING A* , widely used  known form of best-first search & path planning algorithm nowadays in mobile robots,games. this is the function for A*,                                     f(n) = g(n) + h(n) g ( n ) is the cost of the path from the start node to n , and h ( n ) is a heuristic function that estimates the cost of the cheapest path from n to the goal This will find cheapest f(n) value in neighbor nodes to archive goal node. check below image  A to B path finding with g(n),h(n),f(n) value In the final level check below image Now we will check the Algorithm // A* Search Algorithm 1. Initialize the open list 2. Initialize the closed list put the starting node on the open list (you can leave its f at zero) 3. while the open list is not empty a) find the node with the least f on the open list, call it "q" b) pop q off the open list c) generate q's 8 successors

Create ROS Package

Hi let see how to create ros package package createing command eg : catkin_create_pkg  <pkg_name>  [depend1]  [depend2] ... catkin_create_pkg :- this is a keyword to create pkg pkg_name :- u have to choose ur pkg name depend : it means ur pkg depend in what. for a eg if u like to do ur programming in python u need to add depend as rospy like wise   python --> rospy   c++       --> roscpp msge    --> std_msgs lets create one sample pkg name call robin . First  u need to go catkin Dir. then u need to go src folder .bcz all pkgs located inside. u have to create ur pkg inside the folder copy& paste in ur terminal catkin_create_pkg robin rospy roscpp std_msge output :- Created file robin/CMakeLists.txt Created file robin/package.xml Created folder robin/include/robin Created folder robin/src Successfully created files in /home/robinrobotics/catkin_ws/src/robin. Please adjust the values in package.xml. in this folder if u like to add c++ c

Navigating the ROS Filesystem

For this tutorial we will inspect a package in ros-tutorials, please install it using        sudo apt-get install ros-<distro>-ros-tutorials rospack allows you to get information about packages       rospack find [package_name] roscd , It allows you to change directory        roscd [locationname[/subdir]]   pwd , print the working directory using the Unix command        pwd  echo , display the output in terminal        echo $ROS_PACKAGE_PATH rosls  It allows you to ls directly in a package by name rather than by absolute path.         rosls [locationname[/subdir]] rospack = ros + pack(age) roscd = ros + cd rosls = ros + ls  

Understanding ROS Nodes

Its a basic thing & main part in ROS . Nodes are executables that can communicate with other processes using topics, services, or the Parameter Server. Node can be create in python , c++ , Lisp Two nodes can communicate each other using topics (interchange meassage/data  ) Every nodes have to named by programmer.that name used to communicate or identified by other node. roscpp is lib to create ros node in c++ & rospy for python language In ROS have some  commands to retrieve the running nodes information rosnode info node : This prints information about the node rosnode kill node : This kills a running node or sends a given signal rosnode list : This lists the active nodes rosnode machine hostname : This lists the nodes running on a particular machine or lists the machines rosnode ping node : This tests the connectivity to the node rosnode cleanup : This purges registration information from unreachable nodes   rqt_graph :  Provides a GUI

Setting up Arduino lib in ROS & Arduino IDE

 Hi guys let see how to setup arduino with ros(robot operating system) Before this step u need to install arduino & ros in ubuntu Then after u need to copy & paste this code in ur terminal and press ENTER        sudo apt-get install ros-indigo-rosserial-arduino       sudo apt-get install ros-indigo-rosserial  press enter . then u need to find out arduino lib folder in ur HOME & open ther terminal on it then u need to copy & paste this code in that terminal          rosrun rosserial_arduino make_libraries.py  and press enter . then open the arduino IDE and upload a sample code in ur board  Now let see how to do in ros . check whether ur ros arduino lib is install or not. start the ros master using " roscore " connect the arduino with ros           roslaunch rosserial_python arduino_one.launch   in arduino publisher node name is chatter ..  we can check its work or not  using " rostopic list " we can display the chatter node u

obstacle avoidance using laser scanner in ROS

ROS node to perform obstacle avoidance using the values from the laser scanner Simulate the designed robot in Gazebo ROS node  coded in python Code is below link  click here

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