LEGO NXT Rocker-Bogie Suspension Demo I

[holyhell5050]

Ugh, what annoying comments "blah blah blah I know better blah blah blah". Great job my friend.

I am working with NXT and primary schools and want to do some interesting stuff about the Mars science laboratory. If you could send me/forward me to some pictures from different angles or a building guide I would greatly appreciate it because I have little time to work this out myself.

[drknuth]

Thanks for the friendly comment! I started from the design in Brian Bagnall's book Maximum LEGO NXT. The axles he uses to transmit power to some of the wheels store energy and oscillate. So I replaced them with gears to bring the power down directly. I dont have instructions for my mods, but I would start with Brian's book. If I get a chance to take photos, I will get them to you.

[holyhell5050]

Thank you very much. A copy of Mr Bagnall's book is on its way to me now.

[aymx]

cooooooooooooooooooooooooL

[Bajwa909]

youd better be careful with that thing

[drknuth]

Slow, but forceful:

Power = speed x force

Speed is not the objective here.

Deliberate, unstoppable mobility is the objective.

[Degr8n8]

Whats the difference between power and force lol? btw the equation goes Force= mass X acceleration. Trust me i did physics. Btw suspension in an rc car like that is completely pointless ye i admit that its neat and u did a good job but a lot of the energy exertred from the motor is absorbed by the suspension. The only advantage to suspension is you get more traction but thats only true if you have a long car with the wheels far apart other wise its pointless.

[drknuth]

This isn't a car... its a rover.

The suspension system is called a Rocker-Bogie suspension and this is currently used on the Mars Rovers to give them mobility in hostile terrain.

Force and power are not equal... trust me I am a physicist. Power is conserved, since energy is conserved. This is the entire reason for having gears. With P = F v, you can increase the force but you sacrifice speed. Alternatively, you could increase the speed, but then you'd have to decrease the force.

[14080yo]

its not a romote conntrol car(rc car)it a great design that was custom programed into a 300 $ piece of machinary,with an awesome suspention system,btw great show drknuth!

[holyhell5050]

Just to hammer another nail into the coffin on this;

work = distance * force

power = distance / time * force

and since

distance / time = speed

power = speed * force

Don't forget that the equations you learn in physics at school are initially presented with the impression of being static, but with a bit of algebraic manipulation you can mix them up to make your own - if you should need to.

I realise it's 11 months ago but I can't help myself :P

[drknuth]

Ha HA!

Thanks again for the friendly comment and clarification. I find this thread funny since the kid above who doesn't know the difference between power and force says 'Trust me i did physics'. Unbeknownst to him, I am actually a physics professor and a former NASA scientist. Its a good thing he didn't take my class because he clearly doesn't do physics well.

[holyhell5050]

That comment of "trust me I did physics" touches a nerve with me - it's not the first time I've seen someone who doesn't know what they're talking about say such a thing hehe.

I had a physics teacher who almost screwed up our courseworks - he didn't because I suspected he was wrong. But because he "knows physics better than me" I had to get two maths teachers to confirm that I was right and sign off on it. How's that for arrogance? :)

Being a NASA scientist must have been nice :)

[magemager0]

you "did" physics?