Description of issue:
-first year seriously considering mecanum drive on a competition bot, played with it last year
-after adding robot level weight to our mecanum (using old dead batteries), we began to experience dramatic drop in Battery Charge. In simulating a match (2:30 sec), driving around at 100% speed, and some pneumatic operation, the battery charge would drop from 130% to 65-75%
-After each cycle, the cims, battery lead, and talons would be fairly hot
-After testing the bot in tank mode, the battery dropped only a difference of 10%
Theories regarding issue roots:
-wheels aren’t perfectly aligned, with a difference of about 1 in L vs W.
-amperage issue? we aren’t currently monitoring amperage pull per cim and my controls people don’t seem to have any clue as to how. I’ve heard the number 15 for amps, but I don’t know how much we are pulling.
-hardware failure? control board or other major board is failing?
-not a singular battery issue
-likely not a battery beak issue
Any ideas or comments would be greatly appreciated. We really don’t want the purchase of wheels to go to waste and interfere with out strategy.
I have coached teams that have used some version of mecanum drives for over 5 years. From my experience, what you are describing does not seem unreasonable. The physics of mecanum drives mean you loose half of your force vector just driving forward. Strafing is VERY inefficient as well. If you tack on a compressor, that charge loss is expected.
P.S.: Not to down play mecanum. It is an excellent drive.
P.P.S.: make sure you have set your wheel in the “X” formation.
sorry for the quick answer, but i’ve been up late with a 7 month old with a bad case of RSV for the past two nights. The ratio of 1:1 of the forward and perpendicular vectors was a mistake stemming from a long held assumption (and wrong I might add) that mecanum works the same way an omni drive does. I believe you proved this assumption wrong with this quick paper back in 2010.
I would ask the OP what gear ratio/FPS they are running with.