I'm working on my first "robotic" project that involves a square platform that should drop one of the four sides at a time.

     side 1
  |          |
4 |          | 2
  |          |
     side 3

My idea is to mount {something} in each corner [A, B, C, D] and for example to drop to side 1 I would pull down corners A and B. Then back up again and drop another side. The platform will be circa 150 x 150 mm and has to tilt to circa 45° therefore that {something} has to go down by around 150 mm as well.

What is that {something} that I should use? I was googling for a while but I don't know the right names for the parts, that makes googling quite challenging. Is it a gear rack? Or Linear actuator? Or some kind of electric piston?

Is there any site somewhere for aspiring makers that lists the common parts and mechanism items? And ideally where to buy them cheap too (this is a little school project on a very limited budget).

  • $\begingroup$ what you are describing is a tilt table .... here is a simple example .... youtube.com/watch?v=EN-1pWblSAw $\endgroup$
    – jsotola
    Commented Jun 1, 2019 at 17:49
  • $\begingroup$ Ever sat in a chair or at a table and it won't stop wobbling? Tripods don't have this problem because any three points can exactly define one plane. If you have four points (as in your drawing), then you can no longer use your points to define an arbitrary plane. With four points all of your points must lie on an existing planar surface. (Near-)Perfect planes are hard to find in real life which is why the chair always wobbles. You'll face the same problem with this setup: if you don't move two actuators in perfect unison then either the actuators will bind or you'll bend the plane material. $\endgroup$
    – Chuck
    Commented Jun 24, 2019 at 18:49

1 Answer 1


This is called a Stewart platform. You can use any linear actuator type, hydraulic, pneumatic or electric.


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