Originally Posted by WoodSnarfer *snip*
Next, I'm off to do some acceleration calculations...I wonder how quickly we should expect a 150 pound gantry to accelerate from zero to 2.5 inches per second...
*snip* |
Use Newton's formula for acceleration: F = ma (or, in this case, a = F/m).
F force in newtons,
a acceleration in m/s^2,
m mass in kilograms.
I'm not sure what has to be done to make this formula work with imperial units; perhaps the easiest is to translate your units to SI ones:
m = 150 pounds = ca 68 kg
F = 377 lbf = ca 1677 N
v (target velocity) = 2.5 in/s = 0.0635 m/s
a = F/m = 1677/68 = ca 24.5 m/s^2. So taking only the mass of the gantry in consideration you would reach 2.5 in/s in just 0.0635/24.5 or just under 3 ms! This won't be the case of course, because of screw and motor inertia, friction (which makes the available force less than the ideal, calculated one), motor inductance (it takes some time for the motor to develop full torque), and probably a lot of other things too.
Arvid