Hardware recommendations to synchronously drive Dual 50A hobby RC motors

hardware support
1

I need to synchronously drive two high speed flywheels. I want to do it with consumer level, accessible hardware cheaply available to anyone. I can easily drive hobby RC airplane motors using ESCs and a microcontroller, but in this application the relative speeds of the two flywheels is critical and simply pushing a pair of identical hobby motors/ESCs with a common PWM signal produces unsatisfactory results.

Despite the hardware being the same, the flywheels often have observably different rotational velocities. I am assuming this is due to variations in physical properties of the hardware. FOC would seem a good way to manage the speeds and I started on a learning journey with SimpleFOC.

The target velocities for the flywheels are in the 10s of thousands of RPM, with initial testing at around the 10,000 PRM mark.

I am currently looking into literally gluing magnets to the motors and using Proportional Integral Derivative Control with the ESCs and AS5048s to synchronise the flywheels because I keep starting fires with the MKS DUAL FOC V3.2 I purchased.

I don’t want to reinvent the wheel and it seems to me the SimpleFOC libraries have already done the work.

I am a “Jack of all Trades, Master on none” and am overwhelmed at the prospect of designing my own board. Even understanding what the wizards in this community are discussing in the hardware threads about board design is beyond my skill level.

I would like to use ESP32s as I am somewhat familiar with them and have some on hand. I have a need to control multiple motors, both high speed like these NEEBRC 3542 920KV/1400KV Outrunner Brushless Motors, as well as lower speed high torque ones like the GM6208-150T Gimbal Motors I purchased, and also servos or stepper motors to drive screw jacks that accurately adjust physical component parameters, and record output from a load cell…

I need to data log the relative velocities of the motors, positions of servos, and collect load cell values. I was planning on using EPS32 Now to bring these together.

SimpleFOC would seem to me to have already done the heavy lifting for all this.

Can anyone suggest some hardware that might suite the purpose? I would love to simply be able to get some made with a service like PCB Way. Any such board would need to be publicly useable, if not under a public license.

All/any suggestions welcome. :cowboy_hat_face:

2

What issues are you facing with that approach? To be honest, it seems much simpler and “off-the-shelf” than using SimpleFOC. You would have to glue the diametric magnets anyways for the position sensor in either approach. At 10K rpm and an ESP32, and any commonly available pid library taking the position sensor as input and ESC servo signal as output, you will probably get acceptable results.

3

Thanks @motormaker

None as yet. I may just be impatient, the magnets I ordered have been stuck with Canada Post since Nov 6th I was thinking that I would skip the magnets/sensors on a FOC solution after reading @dekutree64’s suggestion, thinking to to simplify the hardware.

You have convinced me to give it a whirl. Pun fully intended.

4

I like the idea of using regular ESCs since SimpleFOC can be difficult to reach ultra-high speeds, but the magnet and AS5048 seems like overkill when all you need is a speed measurement. A single hall sensor placed where it can detect the motor magnets would do the trick. Or perhaps an optical sensor to detect a mark passing by on each revolution.

5

You guys rock. I am a fan of KISS and it usually tell me I am on the right path when the simple solution offers itself.

I just happen to have a few Hall sensors hanging around, noticed them last night when cleaning up and thought I had wasted my money buying them too!

getting excited again. :grinning: