[REVolution]

I'm helping with my high school's robotics team and I am in charge of the team that does the chassis and drive line. We typically get 4 SIM motors to run the gearbox. The team that is working on an arm attachment might need one of the motors which leaves me with 3. Unfortunately, I would need all 4 for added strength to move the robot. We got a kit with a lot of stuff in it and we don't have to use what is in the kit but we do have to use their motors and not anything else or any more of them. I would need to figure out what ratio gears I'd need to go faster yet have some torque to be able to carry 160+lbs on the robot. Is there any calculation to see what I need to figure out?? I want to be able to have that thing acclerate and have a decent speed yet have some torque. I don't need a 2 speed gear box to do it, since it would just complicate matters and it is a bit unnecessary. Any help would be great.

[jspookss]

:ohmy: *quietly tiptoes out*

[REVolution]

hahaha

[Scout]

There is a rock and a hard place you got stuck in. As you know you can lower the gears enough to move a mountain but not do it quickly. Since you want to keep some kind of speed and still have power is there a way to increase the power to the motor, or would that burn it up? What is the motor you are using? What are your other guidelines you have to stay within? What are you using for your power source, and are you allowed to alter that since you have to use the motor that is supplied?

[Speed Devil]

Your still in highschool man, aren't you a little too old to be a student XD

[bluestinger66]

How about a centrifugal clutch, like a mini bike, snowmobile or Jr dragster?
Its basically a low tech CVT

They arent cheap, about 650 bucks new, but used ones would work just as well with new springs and weights and belt.
I dont know about reversing though...

[REVolution]

I'll give you guys all the specs tomorrow when I go.

[REVolution]

Ok, so it took me a couple hours but I got the calculations done. I figured in the robot at 155lbs (safetynet) and the wheels we are using are 6" in diameter, and we are using a gear reduction of 4.67:1 from the motor in the gear box. From the out put shaft from the gear box we will have another gear reduction in a 12 sprocket gear to a 15 sprocket gear connected to the drive wheel. After all the calculations were done with about 80% efficiency in the chains we are using we got roughly 12ft/sec. I'll post pics up tomorrow when we have more finished products.

[REVolution]

Ok now I have to build a mini robot that is released by the host robot to climb a pole and hit a pressure plate which is a light switch in essense and has to climb back down the poll to signify the end of the game. Is there any way to post a PDF file on here so that people can see it to better understand what I am doing? It might shed some light on a lot of things...

[jspookss]

Post it as an attachment.

Might work

[REVolution]

http://www.tetrixrobotics.com/lib/galler...oD%2Bus%3D

This is the best I can do.

Based on the info I got, I have to figure out the top speed, how long it takes me to get to 102" (its a 10 foot poll but the minibot can't be deployed any higher than 18") and how long it'll take me to reach the top speed and how long it will take me to get back to below 102".

[REVolution]

The gears we are using that come with the kit are as follows...

40 tooth gear x 4
80 tooth gear x 2
120 tooth gear x 2

The wheel diameter is 4"

The max weight is 15lbs, but obviously the lighter the better. I am trying to figure out how much the battery weighs as well as the motor weights, but I don't have that info as of yet so I am trying to figure out the calculations using 15lbs as the max weight. I think I'll have to convert it into kgs and then back again for ease of calculations.