OK. Here’s a challenge for evryone. This is not easy to do but is possible. See what the highest possible speed you can attain with your VEX is. Post pictures of your bots online. My speed record was a little over 14 fps. I challenge anyone to break that record. I’ll see if I have any pictures of the bot that I did it with but I’m not sure. It was 2 transmissions 4 motor drive so it was fast! I challenge all VEX users to beat my record or go for speed records with different drives such as tread or omni. Anyway post your robots on the forums.
Just wondering, how many wheels did that robot have 3 or 4?
Also, did it go 0-14 feet in one second or was it going full speed when you “started the clock”?
do you have a picture of this fast robot by any chance? it seems to me like a dragracing contest has been started
. I challenge anyone to break that record. I’ll see if I have any pictures of the bot that I did it with but I’m not sure. It was 2 transmissions 4 motor drive so it was fast! I challenge all VEX users to beat my record or go for speed records with different drives such as tread or omni. Anyway post your robots on the forums.
what is a fps?
Feet per second?
exactly. fps = feet per second.
This sounds like fun since i cant get a robot to type “hello world”.
dude thats fast for a vex bot!!!
what gear ratio were you using??
sounds hard to beat, i think ill try!!
OK, to answer the first question here the robot had 4 wheels. However it really only needed 3. The idea of 3 wheels just never occured to me. As for pictures, I’m still looking to see if I have any. I probably don’t but I may rebuild the bot. Next, I’m afraid I don’t remember the gear ratios but I do remember that it started at more than 1:1 and shifted to a ratio that the motors can’t turn without a running start. and lastly, I didn’t actually time the robot to get its speed. I programmed a rotation sensor to measure the number of rotations of the wheel in a second then start over and calculate how many feet it had moved in a second based on the wheel’s circumference. I then had the robot constantly printing to screen the top speed so after I ran it I just plugged it in and saw what came up.
Sounds like a good challenge. However, the speed you calculated might be a bit off, the optical shaft encoders aren’t amazingly accurate - they’re very prone to vibrations.
The speed certainly seemed about right. It is about the max the VEX can attain.
This challenge has flaws though. Not everyone will tell the truth. The top speed is limited to the amount of money you have. The person with the most motors and gears wins. Thats what I think.
Not true. The shifter I built could be done with the starter kit. Granted that is for one and I used two but that partially hurt it because they wouldn’t always shift equally. Also, a smaller and lighter robot can be faster than a big and heavy one with lots of motors.
Oops. I forgot to add this. As for telling the truth, people don’t lie about your speeds. Anything above about 15-17 fps is ridiculous. The VEX simply can’t attain that kind of speed. Also, if someone’s speed seems high they can post pics of their robot so other people can recreate it to prove their speed.
Basically what you just said was that if anyone beats your speed they lied and that you have the fastest VEX robot that can be built. I dont care what you say read your last post and see what you think it really means to everyone else. If someone goes faster than you get over it and try again.
That was a bit scathing. That’s not the way I meant it. My speed can be beat, though according IFI’s specs on the motors maybe not by much. But it is nearly physically impossible for the VEX motors to achieve a speed much faster than 15 or 16 fps.
as of now i only have a starter kit (parts on order) and i made a gear ratio that was extremely fast, but couldn’t pull the robot.
Yeah, that’s what makes this a challenge. The VEX motors are really very weak and the way to make them fast is to use some form of innovative drive train such as transmissions or maybe some form of belt or chain drive.
Again you basically just said you built the fastest vex robot that can be built. If yours does 14-15 FPS and the max is 15-16 then your pushing the extremes of the motors. Im sorry for sounding rude but it seems as though you have set a bar that cant be beat.
I’m curious, what part of the IFI Specs do you think places a constraint of 15-16 FPS on the top speed of a Vex Bot? I don’t remember seeing enough info there to let someone determine a top speed.
I’m thinking that the primary limiting factors will be wind resistance and drive train losses to friction (in everything from any gears used, to the rolling resistance of the wheels); not the capabilities of the motors. Am I overlooking something or perhaps not making the same assumptions you are making?
There’s a spec sheet on the speed the motors can attain with different gearings and chain ratios here. Where the picture is red the motor can no longer start turning from a standstill. And if Tmaxxguy would care to read my original challenge proposal, a regular drive is not the only one I challenge people to set records in. I have never built a fast tread, omni, crab, or servo steered drive. I challenged everyone to set records in any way they want not just the overall fastest. A regular wheeled drive will always be fastest for that because the wheels have the greatest diameter. Also, yes I do believe my speed is near the absolut top, however: A. it can be beaten, and B. there is going to be a absolute top speed the VEX can achieve under any conditions due to the weakness of the motors. There’s nothing I can do if my speed is the fastest the VEX can achieve. So I’ll change my challenge to this: I challenge anyone to match or beat 14fps in a regular drive or set their own records in other types.