Robot doesn't turn in high gear

[Andy Baker]

Originally Posted by JohnMorenski

well i know that this has been posted before but i also know that other teams are having this problem and im sure they want all the info they can get. it seems that we are not getting the full potential out of our andy mark shifters not in low gear, low gear works great, but in high gear. we cannot turn in high gear, the battery voltage on the O/I drops and the motors seem to stall, we are using 1 big cim and 1 little cim on each gearbox any input????

would it be a smarter choice to switch to 2 small cims on each gearbox??

thanks

How fast are you going while in low gear? It sounds like your after-gearbox ratio may be too low... you may need bigger sprockets on your wheels to slow down a bit.

Andy B.

[MrForbes]

Also it will help us help you if you give a complete description of your drivetrain/chassis....ratios, width, wheelbase, number of wheels, tread type, whether the center wheels are lower than the end wheels and by how much, etc.

Long, narrow, 4 wheel robots with sticky tread, and not much final drive reduction, just don't turn easily. Wide, short, 6 wheel bots with lowered center wheels, not so aggressive tread, and more final reduction turn just fine in high gear.

[kramarczyk]

Originally Posted by squirrel

Also it will help us help you if you give a complete description of your drivetrain/chassis....ratios, width, wheelbase, number of wheels, tread type, whether the center wheels are lower than the end wheels and by how much, etc.

Long, narrow, 4 wheel robots with sticky tread, and not much final drive reduction, just don't turn easily. Wide, short, 6 wheel bots with lowered center wheels, not so aggressive tread, and more final reduction turn just fine in high gear.

I'm guessing a 4x4 with a long wheelbase... take a look at this white paper. <edit> Titled: Drive Train Basics
(How to Be Sure Your Robot Will Turn)</edit>
http://www.chiefdelphi.com/media/papers/1443