My team is building a mobile goal lift on the rear of our robot, pretty standard, picks the mogo up with two pieces of c channel and tilts it back into our robot. However, we are struggling to generate the necessary torque. We have two green cartridge motors (no red ones remaining), and a 2.33:1 ratio. Originally opted to not go to 7:1 because the metal gears we have dont fit on our high strength axles (i guess they changed at some point?). Is the better solution to file the edges of the high strength axles so the gears fit or seek out high strength cartridges? My other question is, for teams that have a similar lift, do you use a hold command to keep the mobile goal up when not moving the motor actively? and if you do, do you find it overheats motors?
Not sure what exactly the first part of your question means but I use a hold stopping on my mogo lift motor and it doesn’t cause any overheating for me, unsure if that is a common thing people run into with that command.
I’m trying to built a mogo pickup similar to the non-four bar one on 3859W (astrobots) and i need to up the torque. currently have 2.33:1, was wondering which would be a better solution: swapping the two green cartridges to red, or increasing the ratio thru different sized gears
This is entirely dependent on the torque load acting against the motors. If the stall torque isn’t great enough, the
hold function won’t work (in fact, all it is is a PID loop keeping the motor at a given position using the existing power the motor has to offer). There is no mechanical stop built into motors if that’s what you were implying.
It will force the motor to actively work for longer periods of time which could potentially overheat your motors. If your system is properly tuned, it shouldn’t be the case. Not in any capacity during a 2 minute match period at least.
They sell pinions that accept high strength shafts
You might want to try adding rubber bands to assist your mogo lift upwards. There is rarely a case where you should use a compound ratio so avoid it. They add lots of friction and complexity. The length of your mogo lift arms also affects the load on the motors (think of how a lever works).
Thanks for the info on the details of the hold command. As for the gears, we have them. However, for some reason, our high strength axles don’t fit in them. I was talking to our mentor and he said that one of the other teams had to file the corners a bit so they could fit in those gears. Not sure if we just have really old gears (some of these parts are a decade old i believe) and they’ve changed the dimensions, but this wasn’t a viable solution without some alteration to the axle. What makes it more weird is that the same axles do work with high strength gears of larger sizes. Also, what is so undesirable about a compound ratio?
More friction is added, and it can be heavier and bulkier than 2 gear ratios. For this game you shouldn’t ever need them unless you are building a PTO, but they are often seen in games like Turning Point and Nothing but Net, which had many flywheel robots which needed compound ratios to reach very high speeds