The Vex Speed Challenge

[Arkorobotics]

I was at the testing field I go to to test my Kamikaze Prototype #2 http://www.chiefdelphi.com/media/photos/25233 (VEX). I was thinking, "why am I doing this?" then I thought "I want to be the person with the fasting moving vex". So I came up with this challenge:

++The VEX Speed Challenge++

The challenge is to make a the fastest moving vex robot.

Prerequisites that qualify a bot as a "VEX" Robot:
(1) The robot must have the VEX Microprocessor (controller) or as I like to call it the "brain", along with the radio system. This means you need to use the remote control that came with the Vex set.

(2) The body can be made of any material.

(3) It must be ground based and wheels are not required (you can do something like a hover craft if you want)

(4) Propulsion: It must be electronic. No explosives or chemicals of any sort. It must be motor powered. All energy propelling the craft must be from itself I.E.- no external propellant.

(5) Battery requirements: The robot is allowed 3 Batteries all of which can be running at the same time. No limit on Volts and Amps.

(6) Weight Limit: 10lbs

(7) Speed controllers, spikes, and any extra electronic parts such as motors are allowed at unlimited amounts.

(8) Steering is not required

(9) Must start and end on a flat (or very close to flat) surface such as concrete, cement, etc.

Official Timing procedures (proving speed):

You must submit a video of your robot completing the official Speed Check (available below in image 1). Also a picture of your machine along with a brief description of the propulsion and control.

Speed Check System:
The vehicle has unlimited time and distance to accelerate to line marker A and speed is calculated by mesuring the amount of time from line marker A to B(distance between A and B is 15 feet). I suggest having a timer or two. Record this on video and either post it up your own server or you can email me at dotuplink@gmail.com and I will host it for you.

http://www.arkorobotics.com/images/speedcheck.jpg

Official Due Date: All videos, pictures, and descriptions must be submitted by September 4th, 2006. Post it either on this thread or email me. Official website for the challenge: http://www.arkorobotics.com/projects/

For any questions just post it on here or email me at dotuplink@gmail.com.

*Note: All your action upon this challenge are voluntary, any damage or injury is your own reponsiblity*

Good Luck and be safe.

[lukevanoort]

Oooh, where's me 2005 FP motors driving banebots, say 2:1 (If they make it) and Home Depot light switches + servos? 3 13V NiCd batteries in series, for a power to the motor of 39V? (Hey, it only has to run once) I estimate, with 3in wheels a top speed in excess of 200 mph. (assuming at least 30,000 rpms on the FP given the extreme voltages, maybe even in excess of 300 or more)

[Arkorobotics]

Oooh, where's me 2005 FP motors driving banebots, say 2:1 (If they make it) and Home Depot light switches + servos? 3 13V NiCd batteries in series, for a power to the motor of 39V? (Hey, it only has to run once) I estimate, with 3in wheels a top speed in excess of 200 mph. (assuming at least 30,000 rpms on the FP given the extreme voltages, maybe even in excess of 300 or more)

First off this needs to be controlled by a VEX set, and it can't exeed 13V even when you wire them to give you 39V.

[Tristan Lall]

First off this needs to be controlled by a VEX set, and it can't exeed 13V even when you wire them to give you 39V.Now you know why the FIRST rule-writers have such a headache when they release their rules.

You didn't specify total system voltage, you said "Max Volts on battery". That implies the singular, so 13 V per battery, 39 V for the system seems like a reasonable assumption—unless you're saying that the battery is a collection of up to 3 smaller batteries (that's possible, given the definition of a battery as a collection of connected cells, but represents rather unusual word usage). Also, I'm not sure whether you're looking at the rated voltage on the battery, or the actual measurement at the terminals; these, of course, can be different. Furthermore, if you are looking at rated voltage, a battery can be hotwired to put its cells in series; if you have a battery that is rated with parallel combinations, an enterprising person could rewire it so that it runs at a higher voltage. (I'm sure that that violates the spirit of the rule—but it can't hurt to be specific.) Adding a modifier like "total system voltage is to be measured immediately before the test, and must not exceed 13 V" (or "39 V", if that's what you meant) would simplify matters.

Similarly, the current rating is ambiguous; is it peak system current, or something else? Is it measured at the battery, or at the output devices?

And, if one really wanted to mess with the rules, one might attach a step-up circuit to the battery, to provide some large voltage to the motors at low current. If the current rule applies at the outputs, this could theoretically be somewhat useful.

And as for energy input, I assume that a push start is forbidden, but what about a ramp start? That's the robot's gravitational potential energy being used up, rather than the robot's electrical energy. (Incidentally, the batteries are a form of chemical energy storage; surely you don't mean to exclude them under the no chemicals rule....) And while we're at it, you didn't say that capacitors aren't allowed—say hello to my 100-aerogel-capacitor (http://downloads.solarbotics.com/PDF/Powerstor_aerogel_PS-5102.pdf) array at 250 V; who needs a battery? Similarly (though they wouldn't be too useful), photovoltaics aren't restricted either.

And if you really want to get "out there", and had a budget to match, there's no specification as to the nature of the test surface. If I happened to have, for example, a few thousand Nd-Fe-B magnets, and a very long evacuated metal tube, I could fashion a maglev vehicle powered by a linear induction motor. I wonder how much energy one could store in 10 pounds (less the VEX controller and motor) of ultracapacitors? It's an inside-out railgun operating in a vacuum, so it ought to be interesting to play with.

I'm not picking on you. I'm thinking of alternatives (even crazy ones). So, if you're writing the rules, you need to plan ahead, or prepare to be surprised with what people come up with.

By the way, his system seems like it could be controlled by a VEX set: VEX RC -> servo -> linkage -> light switch (which connects motors).

[Arkorobotics]

And as for energy input, I assume that a push start is forbidden, but what about a ramp start? That's the robot's gravitational potential energy being used up, rather than the robot's electrical energy. (Incidentally, the batteries are a form of chemical energy storage; surely you don't mean to exclude them under the no chemicals rule....) And while we're at it, you didn't say that capacitors aren't allowed—say hello to my 100-aerogel-capacitor (http://downloads.solarbotics.com/PDF/Powerstor_aerogel_PS-5102.pdf) array at 250 V; who needs a battery? Similarly (though they wouldn't be too useful), photovoltaics aren't restricted either.

And if you really want to get "out there", and had a budget to match, there's no specification as to the nature of the test surface. If I happened to have, for example, a few thousand Nd-Fe-B magnets, and a very long evacuated metal tube, I could fashion a maglev vehicle powered by a linear induction motor. I wonder how much energy one could store in 10 pounds (less the VEX controller and motor) of ultracapacitors? It's an inside-out railgun operating in a vacuum, so it ought to be interesting to play with.


Ok! Ok! Ok! Look I am changing the rules to no voltage limit and no amp limit. When I said chemicals I meant like no baking soda and vinegar ideas, no sort of explosive to fire it.

Ramps are out of the question it must start and end on a FLAT (or very close to flat) concrete, cement solid floor. With no grease or anything on it.

Please stop over analizing the rules because you need to see that it is a very simple thing. Loop holes are looked down upon if you really take it to the extreme.

[Arkorobotics]

New Rule changes #1:

(5) No limit on Volts and Amps.

(9) Must start and end on a flat (or very close to flat) surface such as concrete, cement, etc.