# Minibot Ramp

I’ve been reading through all the minibot threads on Chief Delphi that include ramps in the deployment design, and i have found very little in-depth description of their designs. I’m essentially wanting to know, what it is the best angle/diameter for the ramp to maximize the speed/minimize the time of the minibot reaching the top? Im assuming weight, magnets, friction, etc. would factor in. If someone could post the math to figure this out, or what they did to maximize efficiency would be greatly appreciated.
Thanks from team 461,
-Duke

A cycloid might be like a good idea.

If I remember the rules correctly, any ramp or similar device is not allowed to have any effect on the minibot’s speed.

Ramps or the deployment methods are only allowed to move the minibot into a legal “deployed” position.

From that deployed position the minibot has to climb without carrying any momentum or other assistance across the interface between the deployment process and the climbing process.

So (if I am right) I think your question is irrelevant?

Blake

As I understand it, the nature of the ramp would allow the minibot moving itself, to the pole, to be at the best speed possible when it actually climbs the pole unlike other deployments where the minibot sits there possibly on until it hits the pole. A car already in motion moves faster than a car that has to beat inertia and then go for example.

did anyone think of having a “U” so that the mini-bot goes down a pole, then that energy is converted into upward motion, there would be no launch, so it should be legal.

Right … And I think that converting any deployment momentum into climbing assitance is 100% illegal/forbidden in Logomotion.

If the deployment mechanism is a ramp, and the minibot generates it’s own kinetic energy, then it is all legal. The ramp cannot be in contact with the minibot as it crosses the 18 inch line, so it has to be short.

With no friction and constant thrust (torque with no slip) then I believe the optimal to be a cycloid. You really want the math? If you have already reached top speed, then I believe you would just want an arc.

Someone correct me if I"m wrong but I’m pretty sure teams such as 254, 973, 368 and 233 had minibots going up ramps before they even touched the pole. Here’s a video of what the OP is asking about: http://www.youtube.com/watch?v=mmT9nTWqDOU

Also, I clearly remember these minibots with these ramp deployment devices being used at the Championship event so I’m almost 100% sure they’re legal. The rule you are looking at is <G19> and it states:

MINIBOTS must remain completely autonomous and move up the POST solely through electric energy provided after the start of DEPLOYMENT by the permitted, unaltered battery and converted to mechanical energy by the permitted unaltered motors (and associated, appropriate circuitry). <G19> means that HOSTBOTS are not allowed to launch the MINIBOT up the pole at the TARGET, or otherwise contribute to the vertical movement of the MINIBOT. Energy for vertical movement may not be stored in the MINIBOT before DEPLOYMENT (except that which is contained within the battery and excluding incidental kinetic energy stored in the motors or wheels, but NOT, for example, in a flywheel).

While hostbots may not “launch” minibots up the pole, I believe that these teams basically start the minibot’s motors while it is on the ramp so it will use the ramp as a track to gain speed before it gets to the pole (under its own power); therefore, there is no violation of <G19>

You’ll find an interesting discussion of ramps (and their legality) here:

**

I’m gonna make an attempt to divert this discussion back to what the OP was asking about.

We too have been thinking of making this setup on our robot just to have fully optimized the task even if it wasn’t at the competition.

I know I would love to get some input from teams like 233, 190, 254, 1114, 2056, 217, 71, 973, 368, 1986, 177, and any and all others that I couldn’t think of on Duke461’s questions and any other details on how they managed to pull off the awesomeness that is the ramp deployment.

Thank you Jay.
I’d like to keep this focused on my original question, not the legality. There are a multitude of other threads to discuss that and that was not an intended part of this discussion.

That would be illegal. The upward motion has to come SOLELY from the motors of the minibot, not gravity and acceleration gained from the U. but thats another discussion for another thread.

Exactly.

Thank you Richard
Im not the most studied on my physics and whatnot yet, but on wikipedia it says the Cycloid is for “the curve of fastest descent under gravity”. Does this method still apply for upward descent? Thanks.

Other suggestions and statements regarding minibot ramps, and not their legality, are greatly appreciated.
Thanks,
-Duke

I understand how this works, but do you have any suggestions as to performing the experiment?
Thanks.

My opinion: Straight horizontal ramps are legal. All energy comes from the minibot.

Ramps that go down or “U shaped” ramps are not, as potential energy is gained.

we just used some good old fashion guesswork and intuition

As i said before, this is not a thread for discussing legality.

Yay for guessing :]

The cycloid curve solves the classic (~300 year old) brachistochrone problem. The important feature of a such a “curve of fastest descent” it that it converts all of the falling particle’s energy from vertical to horizontal motion in the least time. Applying the same criterion in reverse, to convert a minibot’s energy from horizontal to (upward) vertical motion, will yeild the same curve.

Ah. Thanks for all the help.

Our team thought the same as you. When we saw several ‘ramp’ teams at championships who had a significant downward angle to their ramp so I questioned the lead inspector in Archimedes. Several of these teams were among the fastest in the field, and the downward angle allowed them to use larger axles (gravity helped the acceleration of the bot).

He confirmed that gravity CAN be used to accelerate the minibot (again, according to the lead inspector).

Had we understood that intricacy of the rule, we certainly would have gone ramp and our deployment would have been very very different.

Anyway - thanks for the cycloid. I wasn’t aware of the interesting history behind it.

In these cases, I’m assuming the minibot was under 30" from the ground at all times, correct? If not, one could argue that <G22> was being violated.

Indeed, in the instances we questioned they were under the deployment line at all times.