Steps for Execution the Turtlesim

Start ROS in the terminal using the command:

$ roscore

Start the turtlesim node on a new terminal using the command:

$ rosrun turtlesim turtlesim_node

Execute the program using the following command:

$ rosrun my_package turtlesim.py 2.0

Below is the implementation:

Python3

#!/usr/bin/env python
# author : Sumanth Nethi
import rospy
from geometry_msgs.msg import Twist
import sys
 
 
def turtle_circle(radius):
    rospy.init_node('turtlesim', anonymous=True)
    pub = rospy.Publisher('/turtle1/cmd_vel', 
                          Twist, queue_size=10)
    rate = rospy.Rate(10)
    vel = Twist()
    while not rospy.is_shutdown():
        vel.linear.x = radius
        vel.linear.y = 0
        vel.linear.z = 0
        vel.angular.x = 0
        vel.angular.y = 0
        vel.angular.z = 1
        rospy.loginfo("Radius = %f", 
                      radius)
        pub.publish(vel)
        rate.sleep()
 
 
if __name__ == '__main__':
    try:
        turtle_circle(float(sys.argv[1]))
    except rospy.ROSInterruptException:
        pass

Output:

Draw a circle using Turtlesim in ROS-Python

In this article, we are going to see how to draw a circle using Turtlesim in ROS-Python.

ROS stands for Robot Operating System. ROS is a set of libraries and tools that help build robot applications. It’s extensively used in robotics projects. ROS is an open-source, meta-operating system for robots. The software in the ROS ecosystem has both language-dependent and language-independent tools. ROS supports Python, C++, Lisp and other languages.

rospy is a pure Python client library ROS. We shall make use of this library to implement our code. Turtlesim is a common tool specifically made to teach ROS and ROS packages.

The idea is to import Twist from geometry_msgs.msg library and assign appropriate values for velocity components. Twist expresses the velocity of turtle in 3D space broken into 3 linear components and 3 angular components. Turtle here is 2D and is governed by 1 linear component (x-component) and 1 angular component (z-component). This is because the turtle cannot move in y or z directions. Hence. all other components are equated to 0.

Tags:

#python-modules #Project #Python #Python Programs #python

Stepwise implementation:

Steps for Execution the Turtlesim

Python3

Draw a circle using Turtlesim in ROS-Python

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