Introduction

Usually, when you are working with small robots you miss some sensors, like lasers. Of course, for most of the cases you do not need them, but in my case I needed sensors for advanced navigation algorithms (Area Center Method). As ePuck does not incorporate this kind of sensors, I decided to built a virtual one

Basic Idea

VirtualSensor InfraestructureWe have all the robots into a table, as the robots are small, we can put various of them. A camera is set over the table (zenith position), transmitting images of the robots.

Now, the basic process is the following:

  • Fetch an image of the environment current state
  • Find the robots
  • Process the sensor, according to the image
  • Transmit the sensor information to the robot

ePuck wearing a hatAs you see, the hole process is simple. For the robot finding, we will “wear” our robots with a funny hat. This hat is a mark that will make very easy the robot localization. I have used ArUcO, a fast library written in C++. Now, each sensor needs a particular algorithm. For the laser:

  • The robot centre is determined
  • The image is binarized
  • Each laser beam is calculated from the robot to the closest object (or maximum range)

The sensors

In the Virtual Sensor Library you will find the following sensors:

  • Laser: A basic laser sensor
  • Proximity: Distance (in mm) to other robots wearing a hat or special points you can set into the image
  • Compass: An ArUcO’s mark is used as North
Virtual Laser Sensor

Virtual Laser Sensor

proximity

Virtual Proximity Sensor

Videos

Here two videos, the first one shows how the laser and proximity sensors are used with two robots. Each robot have to travel to the opposite side of the table, avoiding the walls and the other robot

The next video shows the robot avoiding static obstacles in the travel to its target. In both videos, the robots are using the Area Centre Method for navigation

Publications

  • Hardware and software infrastructure to provide to small-medium sized robots with advanced sensors, Workshop of Physical Agents (WAF), 2012 XIII World Congress, ISBN: 978-84-940469-0-2. Manuel Martín-Ortiz, Javier de Lope, and Félix de la Paz. Download

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