Robot arm with brushed DC motors

Community General Discussions
1

Hi,

I have a generic HW+SW system that can control multiple brushed DC motors (using A3950 controllers). I’m looking for a robot arm (~4dgr of freedom) to demonstrate the capabilities of this system. Something in <1000$ range. I would like to hook up directly to DC Motor input (A/B) and encoder signals.

Most robot arm options (e.g. Lynxmotion AL5D) come already equipped with servos that take PWM as input. Perhaps it’s not overly difficult to replace these servos with suitable DC motors + encoders, but I have not been able to find any confirmation of this.

So, my question is, does any of you have suggestions or recommendations how to easiest find or construct such robot arm?

For reference, my system can drive motors with power up to +/-2.8A and 36V.

Thank you in advance,
Alex.

2

The arms in the <$1000 range are almost all servo-based:
robotshop.com/en/robotic-arms.html
You could gut the servos and add your own encoders, but that’s not an easy feat.
We do not carry any in that price range which use DC motors and encoders.
robotshop.com/en/advanced-ro … ators.html

3

Thank you for the information. It is in line with my findings thus far.

After some further search I found perhaps option of using Makeblock kit (robotshop.com/en/makeblock-l … -blue.html ).

It seems to allow control using DC motors. It’s not ideal, but it should allow me to demonstrate my control system. Hopefully I should be able to put together a simple robot arm from that kit. Any thoughts, concerns?

Regards,
Alex

4

The motors included (those which fit their brackets) do not inherently include encoders, so you might have issues there.
Note too that these DC gear motors are not made to “lock” in place or retain a position under load.

5

Yeah. I found Makeblock motors with encoders on the manufacturer’s site: makeblock.cc/optical-encoder … 6v-185rpm/. I ordered the kits through RobotShop.com (since they were on sale), but the encoder motors through the other site. :slight_smile:

Hopefully, if things work right, my control system should be able to keep the motors somewhat steady.

Thanks for the help.

/Alex