Hello, so this year is the second year my team has been together. We are still working on building our first robot for our first league competition.
We are trying to use pneumatics to pull down on our catapult with a rubber band tensioner on the back so we can get both high and low goals. After getting the rubber band tensioner attached we found that we were unable to tension the rubber bands enough to get the high goal. We can get the low goal easily but not the high. This is because we are trying a 2:2 gear ratio but the gears seem to slip because of so much tension.
My idea to fix this was to either use a gear ratio with chains instead of just strait gears. Another ideas was to use no gear ratio and just the rubber bands strait to the motor.
What are your thoughts on this?
Any help would be welcomed.
The reason why your pnemautics are not tensioning it enough is because the stroke of the cylinder (the distance it travels). So alternatively instead of pulling the rubber band down think about the air in the cylinder and how it can be used as a spring. So if you tune the psi to let’s say 30 psi and you pull down on the catapult against this force you will have 30 psi worth of spring tension. This will allow you to shoot both the high and low goal. It just requires tuning so be patient and learn in the proccess.
Hello there! We also experienced a simillar problem. Originally, we had a 2:2 gear ratio (same as yours), but the tensioner would refuse to turn past a specific point. Thus, we opted for a 2:10 gear ratio (12 tooth gear to 60 tooth gear), which gave it enough torque to reach the high goal. I hope this helps! Another tip I would give you is to use a mechanism like the swish mechanism or choo-choo. It is often a lot more reliable to use those than pneumatics.
Ah yes my mistake. But to some extent you can control it by using more cylinders or adding rubber bands or something like that. Though some teams have managed to do this with two cylinders. Check it out on YouTube you’re likely to see it somewhere.