Which motor does the RX-28 dynamixel use?

[vik]

Hi, I'm trying to create a dynamic model for the RX-28 dynamixel, and need to know the motor specs for the dynamixel. I know that it uses a Maxon RE-MAX motor, however I haven't been able to figure out which model has been used based on the nominal voltage, current and dynamixel size provided in the specs.

So if anyone could clarify this, it would be much appreciated.

Regards,

Vik

[jotwe]

Hi,

it's a Maxon RE-max 17 with the part number 214897. Rated at 12V and 4W. You can find the datasheet here:

http://shop.maxonmotor.com/ishop/app?la ... ountry=INT

Regards,

Janis

[billyzelsnack]

Hmm. Interesting. Maybe this is a coincidence, but it looks like Robotis rated the servo directly from the motor stall torque and the gear ratio of the servo.

14.4Nf-mm stall torque * 193 gear ratio in kgf-cm = 28.339952991

The official RX-28 pdf lists "stopping torque" at 28.3 kgf-cm. "Stopping torque" sounds like stall torque to me.

Now let's try doing the same thing with speed.

11500rpm / 193 gear ratio in (Sec/60 degrees) = 0.167826087

Offical RX-28 pdf lists speed at 0.167

I guess the official specifications are just ideal gearmotor numbers, not real world numbers.

Anyone know any of the other motor part numbers to see if the same applies to them as well?

[jotwe]

The RX-64 uses a RE-max 21 with the part number 250003. Rated at 15V and 6W. The updated datasheets on robotis.com give a more realistic rating of speed and torque:

http://support.robotis.com/en/techsuppo ... /rx-28.htm

http://support.robotis.com/en/techsuppo ... /rx-64.htm

[billyzelsnack]

Yep. Looks like the older RX-64 spec was ideal gearmotor values too.

31.6 N-mm * 200 gear ratio in kgf-cm = 64.4
Older spec says 64.4

10600 rpm / 200 gear ratio in sec/60 degrees = 0.1886
Older spec say 0.188