I am taking part in a robotics competition, where the challenge is to create a pair of robots which successfully navigate a series of obstacles. However, the rules state that of the two robots, only one must have a driving actuator. The other must somehow be moved by the other robot, WITHOUT PHYSICAL CONTACT.

I could think of either having sails on the non-driving robot, and moving it with fans on the driving one OR electromangnets on the driving one and permanent magnets with the opposite polarity on the non-driving one. However the problem with both is that efficiency falls off drastically with distance. Thus, I am looking for possible ways to overcome this problem. Thanks :)

Also, the driving robot has a cable power supply, while the non-driving one may only have batteries.

Rulebook: http://ultimatist.com/video/Rulebook2016_Final_website_1_Sep_15.zip

  • 1
    $\begingroup$ Throw things at it. $\endgroup$
    – Octopus
    Commented Sep 10, 2015 at 19:58
  • $\begingroup$ "Must be moved by" - moved or controlled by? For clarity, if you call them master/slave, doesn't the slave get a battery pack? What is the point of giving it batteries if it can't have an actuator? $\endgroup$
    – Chuck
    Commented Sep 11, 2015 at 2:09
  • $\begingroup$ Does "no contact" eliminate towing by a string? $\endgroup$
    – Paul
    Commented Sep 11, 2015 at 4:12
  • $\begingroup$ @Chuck : the rules state "moved by". Also, the challenge is to use some non contact force. The batteries can be used to steer the slave bot. $\endgroup$
    – Vaibhav
    Commented Sep 11, 2015 at 6:28
  • 4
    $\begingroup$ Please post a link to the rules already! This guesswork ain't leading anywhere. $\endgroup$ Commented Sep 11, 2015 at 10:39

2 Answers 2


There are very limited options for effectively transmitting force across a distance, other than with projectiles of some kind which won't achieve your goals or be allowed under the rules.

Based on the rules as given (which mentions having an arm on the hybrid robot), I would assume that the hybrid robot is expected to extend an arm above the eco robot's track to either "push" or "pull" the robot using wind power or magnetism. This gets around the distance issue, provided you can reliably keep the arm from making contact with the eco robot.

Another possible route to take which may or may not work would be to mimic the various bristle bots that are out there (toothbrush head robots, hexbugs, etc) and vibrate the entire table to cause the eco robot to move forward, although that would require fairly significant levels of vibration and some way of orienting the bristles to steer.


Attach a metal square-shaped frame to the first robot, fill the edges with magnets, take your second robot (should have non actuated free moving wheels, like the ones on chairs) and fill it with opposite magnets on all sides, put it inside that metal square, drive your first robot.


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