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as replic said many matches we ran 50%, apperently switching our gearbox from plastic to steel gears was really a bad idea, we had sooo much torque we kept destroying the transmissions on the drills, they really need to come up with better motor mounts next year
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It was still a very neat tranny thoug. Very well designed
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The torque situation is fixed though, thankfully. It was a nightmare replacing the motors in our highschool, but moreso in Annapolis because we didn't have the luxury of time as we did before shipping.
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The problem with our drive train was that the drills were mounted to absorb any forces from stopping too quickly with the drill brakes engaged. This turned into a problem when the mount was actually twisting the motors out of position, and dismounting the transmission. That is why we ended three matches with our drill tranys laying dead on the field. :( We fixed this, in quite a hurry I might add, by making the mounts rigid, now it works like a dream, and faster too!!! :) :D
It was a little hard to see it through the boxes, but we had a little too much speed. The bot actually got some air off of the ramp during autonomous mode and flew through the boxes! :D And if anyone was wondering why our bot was cutting out during elimination rounds, it was because we had all four drive motors and the compressor running (voltage at sometimes was down to 6v). Anyone have the stats on how many amps the compressor draws so we can fix this problem? |
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There is a rule this year that allows teams to control the compressor via speed controller. I'm thinking about using that along with code that will analyze how fast the drive motors are running and adjust the current to the compressor accordingly.
If that doesn't work then we will disable the compressor during matches, our speed is way too important this year. |
If im not mistaken, you only use pneumatics for the grippers to stack and on those extruding bars on your arm. You really only need to charge up the compressor before a match and leave it off. Even the Van Door motor can be off, cause you dont really raise the arms to begin with, just autonomous. You guys didnt really attempt stacking that much. You guys are pretty smart, im sure you will come up with someting that works lol
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Hmmmm.... you're right. Suggestion duly noted!
I guess we'll have to see how many times we can use wings and stackers in conjunction with only the storage cylinders. |
We thought of that before, we only can open and close the arms 3 times with the 2 fully charged tanks and no compressor. We need 1 for autonomous mode, and if we have to plow the oppontents boxes we may need more. And yes the grippers are using pneumatics, but chances are that we are going to change them to something more sutable to our strategy.
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acctually, we always keep the van door motor on, to keep it in the position its in if we dont, it will slowly fall |
Not true Mike, if the arm is all the way in the down position it is turned off.
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See we on the other hand have that problem. Our arm stays 90 degreez to the ground, therefore, the van door is always running keeping it up. What rage_25 just said is what i thought. you guys always fold your arms down, i believed that you would disable the van door from holding it up.
We have a compressor switch, you guys should put one on too. We always left it on, but you guys can have it off and let it pump up again then turn it off. Believe me, you all didnt use pneumatics that much right?? just in Autonomous, and what an automomous that it. The quickest by far!! |
Couple suggestions
First be thankful that this problem hasn't cause your Robot Controller to enter Safe Mode during the voltage drop (when the voltage is lower than radio needed voltage). That happened to MOEhawk at VCU about every match until we re-geared it. The only way to get out of safe mode is to reset.
If you need to run your compressor, run it only when your drive system is in neutral, such as after autonomous routine has executed (takes like 5 sec for your fast bot) or when the joystick is in the deadzone (just add the compressor to the deadzone code). The compressor is notorious for surging at turn on (lil' MOE blows a 20A fuse at every event). As tjrage_25 mentioned before the compressor can run on a speed controller so u can implement a digital filter to bring it up to speed, avoiding the surge. Also, make sure the pressure switch is not bouncing on u turning it on and off rapidly. We always put a delay before we turn off so the pressure will not instantly drop below 120 psi after turn off. For your Van Door Motor powered arms u might want to try the dynamic braking feature of the Victor speed controllers. Pull off (or set to AB) the jumper on the Victor (normally set to BC for coast) to select dynamic breaking mode. These settings only affect the behavior of the speed controller in neutral (PWM 127). Dynamic braking works by connecting the 2 leads of the motor together, essentially causing there to be no voltage across the motor thus no movement (think of it as forced movement on the motor generating a voltage that is fed back into the motor to drive it the opposite direction of the motion). This dynamic brake is not 100% efficient (mostly due to wire resistance), but depending on the force needed to backdrive your gearing and the moment of inertia of the arm it may work. So try the dynamic braking, since it only requires a simple jumper and code change, and it may solve your current draw problem by not running the van door constantly (also save u from van door burnout). I like your proverb "that which doesn't kill us makes us stronger. NOTHING comes easy for team 25" Here is a proverb I came up with while fixing MOEhawk's wings "He who takes everything from everybody is going to lose an arm in the process" Good Luck. See you in Houston and probably about 5 invitationals after that. |
thanks for the help Lucas and Serg. You guys were great at Annapolis.
As for seeing Geronimoe in competition again, I look forward to it, as we've never played against eachother. |
there's always the off season....
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