Servomotor Guide¶
The industrial term servomotor refers to a motor designed for closed-loop control. These normally incorporate a position sensor called an encoder, which may be either absolute or relative. We use servomotors which include a DC motor and encoder capable of measuring relative movement. As such, they are capable of unlimited travel, bidirectional movemenet, and velocity and position control, but only measure motion relative to the starting point.
It is not a hobby servo, even though we colloquially use the word servo to mean hobby servo. Hobby servos have a fixed range of travel, accept a PWM command signal, and do not expose the internal position sensing, so they act as output-only actuators with absolute position control.
goBILDA¶
We are evaluating servomotors from goBILDA as lab stock. These are marketed to education and frequently purchased by FIRST robot competition teams. They are competitively priced for their capability.
The goBILDA ‘Yellow Jacket’ series motors include:
a 12VDC motor with a stall current of 9.2A
quadrature encoder with 28 PPR of motor rotation operating on a 3.3 to 5V supply
planetary gearbox with ratios from 3.7:1 to 188:1
corresponding nominal speeds from 1620 to 30 nominal RPM
corresponding nominal torques from 5.4 kg-cm to 250 kg-cm (0.5 to 25 N-m, 75 to 3470 oz-in)
output shaft options include 8 mm hexagonal and 6 mm D
the 8 mm hexagonal series also offers a 1:1 output (nominal 6000RPM), 1.6 kg-cm torque
Distributors:
Previous purchases:
goBILDA 5202-2402-0027 motor
5202 Series Yellow Jacket Planetary Gear Motor
26.9:1 planetary gear reduction
223 RPM no-load speed
nominal 38 kg-cm (530 oz-in) stall torque
24mm Length 6mm D-Shaft, ⌀36mm Gearbox
four M4 mounting holes on 16 mm square pattern
3.3 - 5V quadrature encoder, 751.8 PPR at the output shaft, 4 pin JST XH connector
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1309 Series Sonic Hub
6mm D-Bore, dual clamp
four M4 mounting holes on 16 mm square pattern
overall diameter 32 mm, overall height 10 mm