Hey y’all. 7480A made it to the Illinois State competition!! We have no chance against better teams so we are going for innovate or design award. We are exploring a six motor double flywheel, adding on two motors on our already four motor double flywheel. What do you guys think?
It’s worth a shot. We tried it on our single flywheel, but we were apparently using bent metal, so the mounts for the extra 2 motors added more friction than the extra motors added power, and the flywheel performed better with 4 motors. Just make sure you use good, straight metal, and you should see a performance boost. Also, if you don’t already have a motor to motor axle to attach 2 motors to each side, you might try that. It reduces friction by removing a gear and axle, and it’s more compact.
Coming from a team that had competed against you just work on you angle and put a velocity pid on it and you will be good and design and innovation doesn’t qualify you for worlds so… Also you only have 2 weeks to build it and tweak It…
Ok, can do. We would not be able to go to worlds anyway.
Couple issues with this, I just finished as a finalist at the Michigan state championship with a 6 motor flywheel. The 2 extra motors were the best decision we ever made. They allowed us to have a 2 ball per second fire rate, while also maintaining 30/32 accuracy on the preloads.
We used a QID to maintain accuracy along with increasing our fire rate in the field. We brought down our fire rate in the finals for strategy reasons but otherwise we went as fast as the robot could. I say put the extra motors on. Battery drain was not an issue for us, we did the preloads at the end of the match all day and never had any issues.
We don’t have any videos on our channel of just our current robot, but it is shown at the end of our states video.
You all should be in the Middle School State Championship so you won’t have to go against the 321s, 333s, 355s, and 1526s in the state ( and hopefully 9571s if we get a skills invite). 99960A looked pretty good in their last event but with either a good field bot or a good full court shooter you all should still be competitive. I would suggest looking at the control side of your shooter, but if you have the 2 extra motors to spare and your shooter is giving out throughout your shots then it might be good to add them to your flywheel. I will add here though that adding or taking away two motors has nothing really to do when it comes to the design award. It is more geared to how well your team’s utilization of the engineering process was along with your recording quality in the engineering notebook. Congratulations on qualifying and good luck in the competition!
QID? Did you mean PID?
Nope I mean QID, Q stands for quadratic.
Actually this is not true. I have a 6 motor single flywheel which I’ve had all season. We ran our entire state tournament on 3 batteries, only replacing the main battery halfway through quarter-finals. You have to wire it right. First you take the motors spinning the same direction, and take one signal directly through the cortex to the motor. the second signal is then run through the power expander and then to the motor. The final motor (the one in counter rotation) is just run from the cortex or power expander. I ran half of my base and two of the motors from my flywheel on power expander. If you do this then you can use twelve motors and not use ports 1 & 10 which have a different voltage curve and response time. Also prevents burnouts of ports because the MC29s will fry before the short can reach the cortex.
It may just be because you have 4 motors, and it sounds crazy, but running the motors at higher control values burns batteries faster since they want to produce more speed, and thus take more current per unit torque than each of a 6 motor. You could also just have bad batteries. My school has found some batteries which charge to >8V, but then don’t even take more than 400mAh of power with an aftermarket charger used for testing (we only use it to discharge batteries completely and to a safe level to preserve their life since most batteries are not useful below 7.2v, but charge batteries on vex smart chargers for competition). They also can’t source more than 3A of current. We test batteries by taking a 25W 10Ohm resistor and applying to the battery with an ammeter and voltmeter in the loop. We can measure the drop and watch as new batteries (charged with a vex charger) hold at 7.8V under load, from >8v, and source 4.5A-5A of current, and some older ones start at 8.0v, drop to 6V and source only 2-3 amps. I’d suggest testing the batteries
we have ran a six motor single flywheel for awhile, and we don’t really have issue with accuracy. Also, we used a total of 8 batteries through out 13 matches, so i don’t think batteries will be much of an issue.
May I ask how this concept works?
Given that there is no proportional term, and quadratic graphs are parabolas (x^2 or y^2), I would guess that a QID controller uses error^2 instead of error * kP. That’s a neat idea, and I will get my team to at least play with it.