MN501-S motor drivers for a quadruped robot

hardware support
1

Hi all!

I am new and interested in building a quadruped walking robot. It’s a project for a university science club, and we have a certain budget. Additionally, we already have some equipment from previous projects to start with:

-6 x BLDC Motor MN501-S KV300
-3 x ODrive v3.4 (one driver handles 2 motors)
-5 x AMT102-V Encoders (for testing purposes only; planning to use magnetic encoders, e.g. AS5048A, as we already have one)
-Several power resistors
-Various laboratory power supplies and a 6S 4000mAh Li-Po battery
-Debix Model A with 2GB RAM (includes CAN, but we are considering a switch to Raspberry Pi)

What we plan to do:

  • Creating a quadruped walking robot utilizing 12 motors (alternatively 8)
  • Constructing the frame using 3D printing for both gears and robot housing
  • Implementing closed-loop control for precise motion control using magnetic encoders
  • We are considering a change in ODrive controllers since the new v3.6 models are expensive, and we don’t have a sufficient quantity. Moreover, we already have the older versions 3.4.

I need advice to start; is it worth considering using b-g431_esc1 controllers in the project?
MN501-S motors operate at 24V with a peak current just under 40A, so cooling systems will be necessary. The current of 40A may occur in the case of heated motors; however, is it worth considering different motors due to such high currents?

Thanks!

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My prediction is that with 63mΩ resistance motors, you’ll burn a lot of B-G431-ESC1s… that board is quite sensitive, and with these motors I’ll expect the voltage spikes to be quite large if you suddenly change direction or load.

You can certainly try with these motors, ODrive should have no problem driving them, but 40A is a lot to manage, for your cables, drivers and the motor itself. Ok, so normally you would not let the current up to 40A, but what if the robot is stalled or something? Be sure to build in some protections both at software and hardware level, or you may find your robot catches fire :-/

There are several people on the forum who are working on quadrupeds, so maybe they have a more qualified opinion to offer than mine :slight_smile:

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