Re: motors/torque

[Steve Edwards <sedwards-at-awger.net>]

Frank Pittelli wrote:

> I get measure the velocity numbers fairly easily with a tape measure 
> and a stop watch, but I'm not sure how to effectively measure the 
> acceleration, since I don't have a speedometer on the vehicle.  Can 
> you approximate the acceleration if I give you (a) max speed with a 
> rolling start, (b) time to go 10 feet from a standing start and (c) 
> time to go 20 feet with a rolling start?


All data is good!

a)  standing start, time to 10'

b)  standing start, time to 20'

c)  "flying ten" -- accelerate to full speed, then time to traverse 10'

d)  neutral or pivot turn, time for 90 deg.

e)  neutral or pivot turn, time for 360 deg.

If you know there's a drastic difference between performance on  
pavement vs grass, above numbers for both.

Also, if you could please verify:

f)  drive sprocket outer diameter (this is friction drive, right?) and 
track thickness

g)  time to accelerate unloaded drivetrain to full speed (ie 
free-running treads, without vehicle weight). I'm guessing this is less 
than a second, but I thought I'd make sure.

h)  weight of vehicle (I've been using 100 lbs).

i)  current being drawn by the motors with drivetrain at full speed 
(unloaded and, if you can manage it, loaded as well)

    - Steve "yeah, it's a slow day" Edwards