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Mapping with sonar? RRS feed

  • Question

  • Hi there

     

    I want to create a map of my environment with my Fischerteknik robot that I made- It has 2 sonar detectors on it at the front of the robot at an angle from each other and I have rotation sensors on the wheels on the form of mechanical push buttons beign pushed roughly 25 times per full wheel rotation.

    Would like to know if there is a mapping addon to Robotics studio that I could use to easily do this or if anyone knows how I would map using sonar and Fischerteknik technology?

     

    Your help would be greatly appreciated

    Matthew

    Tuesday, September 30, 2008 7:55 PM

Answers

  • What you are talking about is a process called SLAM - Simultaneous Localization and Mapping. This has been the subject of research for many years and it is not an easy task.

     

    You have given yourself a difficult job with only two sonars and 25 "ticks per revolution" on your wheels. There will be a fair amount of uncertainty to deal with, both in the robot's position and in the sensors. The robot probably will have some amount of wheel slippage and the sonar sensors will get occassional bad readings.

     

    Sonar sensors view an arc in front of the robot. You will need to estimate the "field of view" of the sensors. Then for each measurement you can draw into the map a pie slice that matches the range obtained by the sensor. As you move you will have to update the robot's position in the map. As a first attempt you could just do this, but the map is likely to be unreliable and probably distorted.

     

    One of the classic textbooks on the SLAM is Probabilistic Robotics by Thrun, Burgard and Fox. However, there are other approaches.

     

    Maybe you will get replies from other forum members.

     

    Trevor

     

    Wednesday, October 1, 2008 3:10 AM