Now that the 3d printer is working it's time to move on to the next thing. I'm finally starting up my self-balancing unicycle project and I'm working through the planning stages. This will be loosely based on the Orbis Urban Mobility Vehicle
. A couple of the things I already have on hand and I'll be acquiring the rest shortly.
I'll be using:
Arduino Uno - GOT IT!
Sparkfun Triple Axis Accelerometer & Gyro - MPU-6050 (part# SEN-11028)
Currie 24V 450W motor w/ 11 tooth gear - GOT IT!
Batteries - start off with some small SLAs and graduate to LiFePo4s or something.
MX350 mini dirtbike rear wheel assembly w/ 80 tooth sprocket (12.5" rim, so maybe 15" total dia.?)
Motor controller: I'm still up in the air, I may go with the OSMC, MegaMotor Plus or the Pololu 24v23 CS. The MegaMotor is preferred as it's a shield for the Arduino and it has decent power handling for a reasonable price. (I'm trying to figure out how to set it up according to the manual but it's a bit confusing. Help would be appreciated.)
I did some basic calculations and think the 450W motor should work well, tell me if I'm wrong.
450w / 24v = 18.75a
450w / 746 = .6hp
(.6hp / 2600rpm) * 62,025 = 14.54 ft-lbs
80 tooth / 11 tooth = 7.27:1 ratio
14.54 ft-lbs * 7.27 = 105.78 ft-lbs
2600rpm / 7.27 = 358rpm at wheel
358rpm * 40" circ (47"?) = 14,320 ipm (16,826?)
((14320 / 12) * 60) / 5280 = 13.5mph
I think the Ratio may be wrong. Should I be using the relative diameters instead of the tooth count? Either way, I think this should provide me plenty of oomph and a decent speed.
I'll need some help with the Arduino coding, but most of it will be there - lots of guys online have their segway clones code up, shouldn't be too hard to convert to one wheel and adjust the inputs from the IMU. Anyone that wants to be involved is more than welcome.