For those unfamiliar with our team, here are some of the features our our robot - “The Ocho”! Always ready to play and spin up 4 rotors!
It starts by showing our unique floor gear pickup
deployment in slow motion.
The video also shows our side gear auto mode
that also drives to the other side of the field. This allows us to start cycling gears as soon as teleop starts.
Our floor pickup automatically retracts
when sensing a current spike in the Talon controlling the intake wheels.
We close by showing our** pilot-free gear drop**
off and fast climb.
Yes, the current-monitoring to pickup the gear is pretty sweet. We implemented that too when we added the gear pickup for Pine Tree.
I believe we only have two buttons for all things gears: 1) “harvest gear” which deploys pickup, begins spinning in roller, and waits for a current spike to stop spinning the roller and retract the arm and 2) “place gear” which makes the fluid motion to tilt out the arm to get it at the right angle for placing, then makes the little dance of spitting out the gear, lowering the gear arm, and backing up… then stowing the gear arm when done.
Sounds very similar to what we run with the exception that 319 pulls the gear into our collector at a constant low amperage to help hold it tighter as we travel the field.
Interesting. We solved that problem by compressing the gear collector roller with our retraction cylinders. The red crossbar pushes the roller into the gear clamping it in place. See this pic.
(Sorry to hijack, back to the regularly scheduled programming)
Each setup will be different. We experimented with different current values and time. If you look for only a value and do not have a duration, it will trip the current value on motor startup. Our lead programmer would be happy to show how we did it this weekend.
Also, it’s been a while since we’ve held up a blue banner. Getting the double last weekend was quite the experience.
PS: We are thrilled to have finally made the full switch to all Talons!
Those are exactly the concerns that our head programming coach brought up immediately. We’d love to get chatty with your programmer(s) about it at DCMPs. See you there!
This can be improved by implementing the Talon’s ramp rate feature. If you’re slamming full voltage into the motor at startup, it will draw quite a bit more current than if you ramp the voltage to the motor over time.
As the operator, I only press 2 buttons for gears also, but except for monitoring current spike, we just have a banner sensor that is looking to be tripped.
What motor do you use to do this? We were considering doing the same, but we didn’t want to burn out the motor. We’re using a bag motor on a 10:1 versaplanetary. Also, is it necessary to use control the current or can you just set the output at a low value?
Assuming that no motion occurs (gear is fully sucked back and motor stalls) then setting a voltage is just a form of open-loop current control.
Also, to convert the Vex locked rotor at voltage data to currents (at least in the portion where the motor has not yet begun to fail), multiply the voltage by the stall current / 12V.
If a motor has a stall current of 135 Amps at 12V, then it’s stall current at 2V will be 2/12*135 = 22.5 Amps.
Using the talon current limit is better/easier than doing open loop voltage because you don’t have to turn the motor up to a higher voltage if the object slips to be sucked back in.
