General Misc > Misc

make a robot follow you

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radhoo:
Unfortunately it doesn't or at least I wasn't able to overcome one major problem: the IR light gets reflected, and instead of detecting my position, the robot will head for a wall...

On the other hand I was able to make some progress on the Ultrasound approach:
Ultrasonic Barrier circuit

(Schematics are here: http://www.pocketmagic.net/2013/04/detecting-an-ultrasonic-beacon )

This has a nice range (up to 4 meters) and the output signal variates with distance. So not only that I am able to detect the beacon, but I also can estimate the distance to it. However getting this to a reliable method is not an easy path. There are some drawbacks here also, most annoying one is that motors also make ultrasonic sounds... creating a high amount of noise.

Still open to any suggestions..

jwatte:
Sound also reflects off walls and other objects. Also, ultrasonic sensors may be much less reliable (and have lower range) when you're outside, especially if it's windy.

If you have problems with wall reflections for IR, then the next step might be to use a camera and some image recognition code. For example, you could make a bright yellow ball of a known diameter and put it on top of the other device. The camera can scan for this object, and when it sees it, calculate the angle, as well as approximate the distance by measuring the size. This can be a very robust solution, but costs more both in dollars and compute power. (Not doable on an Arduino by itself.)

SushiKitten:
I managed to get a robot to follow my hand by using SHARP IR sensors. The algorithm went something along the lines of if the sensor readings are too low, go forward. I was only able to get the robot to follow forward, but with another robot that had six or seven sensors at different angles, I could get it to follow my hand along turns as well. Not sure how well it would work for following another robot.

radhoo:
Hi Sushi, unfortunately that can't be adapted to a case where the user walks and the robots needs to "walk" along.

However, I made some excellent progress today, and I am closer to achieving this project's goal. Here's a demo vid:
Ultrasound guided human following robot

Details on the construction and the algorithm are posted in the construction log, here:
http://www.pocketmagic.net/2013/02/android-controlled-robot-part-2/#130409

Now I'm building three additional ultrasonic sensor boards, to fix some of the current issues.  8)

newInRobotics:
Well done. Looks really good  :)

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