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Offworld-Robotics / numbat_software

Off World Robotics NUMBAT Backend
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Decide on initial designs to prototype for drive base #34

Open StephMc opened 10 years ago

StephMc commented 10 years ago

Pick 2 designs to flesh out more & do rough prototypes if necessary

Gwylim23 commented 10 years ago

Hey everyone mech and design related i have finished a rough design in CAD just so we can see what it looks like a bit easier, catch you all tomorrow

StephMc commented 10 years ago

I've done the motor calculations spreadsheet https://docs.google.com/spreadsheets/d/1ClQX6eNzlmo-wUl56UGNf4egd2rMxN_r7XBAuSIF1vI/edit?usp=sharing. Its based on http://www2.mae.ufl.edu/designlab/motors/EML2322L%20Drive%20Wheel%20Motor%20Torque%20Calculations.pdf. It'd be good if someone with a mechanical background could look over this.

The current spreadsheet has the motor values for a bag motor (http://www.vexrobotics.com/217-3351.html) with a 100:1 gearbox (http://www.vexrobotics.com/versaplanetary.html), one for each wheel. From the calculations it seems this could work with plenty of head room if we need more torque. This assumes we use the 42cm beach wheels.

Heads up for @Gwylim23 @yilserkabaran. Also for Daniel and Chris if I could find their github accounts...

StephMc commented 10 years ago

More motor specs (http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=6&ved=0CDQQFjAF&url=http%3A%2F%2Fwiki.team1640.com%2Fimages%2F9%2F91%2FMotor_Specs_2013.xls&ei=pMb2U4CaIsTHuASmloDIDQ&usg=AFQjCNFNzwDZzRDuINSnJB-OH5kLVz1SuQ&sig2=IA4ahmalh-_AgfqQ5s2cPg&bvm=bv.73373277,d.c2E&cad=rja) - todo: try using these values in caluclations spreadsheet since I think these are taken experimentally and may be better numbers than on the manufactorers website.

CJMilsey commented 10 years ago

@StephMc

Mech feels it is better to use 24cm wheels, does this impact motor selection?

StephMc commented 10 years ago

You can see the change it will make by editing the motor calc spreadsheet. I've just modified it so the wheels are 24cm. We can easily change the gearbox ratio to compensate for the speed drop (so use 50:1 instead of 100:1). Another option is to add a dual intake to the gear box (so it takes 2 of the bag motors). Not sure if you guys think this is needed but it will double the torque if we want it. (http://www.vexrobotics.com/217-3141.html)

StephMc commented 10 years ago

@Omnomnominous Angle gearbox http://www.andymark.com/product-p/am-2622.htm gearbox + motor http://www.andymark.com/product-p/am-2550.htm