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Electrostatic Adhesion help required!

  1. Sep 7, 2012 #1

    I've got a little robotics project that I'm working on, and I've been thinking of adding a little electro-static adhesion gripper to it.

    This gripper will used to pick up an aluminium softdrink can (300ml I think), which weighs 100gm. At the moment, I don't care what it can pick up - I'd even be happy with having it pick up a few small pieces of paper!

    But here's where I get stuck - I have little, or no experience with anything like this - so I'll need layman's terms to explain how to do this. I'm just wondering if anyone could give me a few-paragraph explination on how to make it perhaps?

    I've observed that you are able (somehow) to get 2 pieces of foil, whether that be aluminized mylar, or aluminum foil, feed some power into it, and automagically it picks up objects - I've tried some of this, but without success.

    I have little money to buy parts with, but here's what I got so far:

    - 7.4v 3.6A Li-po battery
    - Aluminium Foil (the kind used in cooking...)
    - Some other kind of foil - not quite sure what it consists of
    - Paper to pick up!

    Any ideas? Will I have to look at getting some kind of transformer to boost up the voltage? I really know nothing, and any help will be appreciated
  2. jcsd
  3. Sep 9, 2012 #2
    Picking up paper with electrostatics may not always work depending on the moisture content of the paper. Paper always contains some water because it absorbs it from the air. Aluminum foil works better. You can just put a piece of aluminum foil on the ground, place a plastic foil above it and rub it and the aluminum should stick to the plastic. Same works with a soda can. If it's empty it only weighs about 10g.

    If you don't want to rub the foil and use high voltage instead you need thin plastic foil with aluminum foil glued to it. Metallized mylar could work but you need to check if the metal side is really conductive. If you place two pieces of this metallized foil onto an aluminum can with the plastic side facing the can and apply a high enough voltage to the two foils they will stick to the can. The voltage you need depends on the thickness of the insulating layer. The thicker it is the more voltage you need. The insulating layer in this case is the mylar + whatever plastic foil the manufacturer may have wrapped around the can. I'm guessing a few hundred volts will do it. Also it would probably be better to use ac because with dc the charge of your foil will eventually get neutralized by ions of opposing polarity settling on the mylar.

    Another option is to use plastic foil that is not metallized, let it touch the can and then "spray" charge on it with a metal needle that has a few thousand volts dc applied to it (or an air ionizer).

    You could also use a mechanical grapple. Or suction cups. Or put an iron object into the can and use an electro magnet.
  4. Sep 9, 2012 #3

    Thankyou very much for this help - I'm a year 10 student, and I have not much experience, this has been very valuable advice - I'll try to remember to post the results here, when I get a chance to test it, I'm in the middle of moving house at the moment (Really - the furniture was taken not a few hours ago!).

    I'm really wanting to stick with electrostatic adhesion - just for the "Wow Factor" of the robot. I'm hoping to put all of this onto my next robot, at the moment I'm preparing a different robot for the National competition of "RoboCup Junior Australia".

    The 'soda' can will be filled with rice to bring it's total weight to 100 grams.

    Thanks Again!

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