Modellsimulation in Webots und Simulationen mit ROS2

Autoren: Arfat Kamal
Betreuer: Prof. Schneider
Art: Praxissemester
Projektlaufzeit: 02.11.2021-20.02.2022

Abb. 1 AlphaBot Simulation in Webots

Introduction

In order to simulate, a 3D model of a 4 wheeled robot is created inside Webots first. That robot is simulated with a controller which is written in C inside the text editor of Webots. That robot is later imported in Webots in Ubuntu and customised with a servo, an ultrasonic sensor and a caster wheel to resemble the Alphabot robot of our project. Finally, it is programmed with ROS2 and it runs in Webots as an obstacle avoiding robot.

Overview

Documentation

Creation of a 3D Model of a 4-Wheeled-Robot in Webots

Abb. 2 - 3D view of 4-Wheeled-Robot

A 4-Wheeled-Robot is created in Webots from scratch by following tutorial 6 in Cyberbotics. The robot consistes of a body, 4 wheels and two distance sensors(IR sensors). The figure above shows the 3D view of the end result.

Co-ordinate System

Abb. 3 - Co-ordinates

The co-ordinate system of the robot works exactly as the picture above depicts. The red arrow shows the X-axis and it defines the right and left of the robot. The green arrow shows the Y-axis and it can be used to move the robot upwards and downwards. The blue arrow is the Z-axis and it is related to forward and backward movement of the robot. By default the co-ordinates system is turned off in Webots. It can be turned on by following these steps: "View >> Optional Rendering >> Show Coordinate System" or by simply pressing "Ctrl+F1".

Top View in a Grid

Abb. 3 - Co-ordinates

The figure above shows the top view of the robot. It is inside a grid to understand the dimensions of the robot. The dimension of the grid is 0.2 × 0.3 meters.

Weiterführende Links

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