How can I shake a thin box up and down sinusoidally without a cam?

  • Level: Undergrad 
  • Thread starter Thread starter secureprivacy
  • Start date Start date
  • Tags Tags
    Movement Vertical
Join the discussion
Registration is free. Start your own thread to ask a follow-up.
Sign up Log in
7 replies · 4K views
secureprivacy
Messages
3
Reaction score
0
Hi

I have a thin box (e.g. like an A4 book) I would like to shake up and down sinusoidally. At the moment I have a flywheel connected to a beefy motor. I have tried using a cam to do it but it has proven not so ideal. What other methods can I use?

Thanks
 
Physics news on Phys.org

Discussion

What's your budget? What period do you need? What amplitude do you need?

You could buy an linear actuator and have complete control over all those parameters. A little bit expensive that's all. :-)
 
Yea its for a school physics competition - so I am keeping things as simple as possible - 1 to 10 Hz and about 5cm max of amplitude?
 
5cm and 1-2Hz seems possible with an actuator. But will be expensive.

Depending on the mass, you could also use a spring?

5cm and 10Hz is quite fast... are you sure your thin cardboard box won't fly apart?
 
Oh just to clarify, its a thin perspex box which weighs about 500g?
 
At 0.05m peak to peak and 10 Hz, the maximum acceleration is
(2 * pi * 10)^2 * 0.05/2 = 98 m/s^2 = about 10G.
You will need a rigid connection that can pull the box down as well as push it up, and the force on the box will be 10 times the weight of the box.

For a simple cam you need to keep the acceleration below 1G, otherwise the box will lift off the cam when it is moving down. That will limit you to about 3 Hz with an peak to peak amplitude of 0.05m.
 
Why not use something like the crank off a bicycle?