Hi alll~
I’m building a 3-DOF attitude control system for a 1U CubeSat simulator as my final year project. The architecture is one B-G431B-ESC1, one Sunnysky V4008 380KV, and one AS5600 per axis, controlled by an ESP32 over UART. All three ESCs flashed, firmware compiled, mechanical bench rig ready. Original plan is torque mode with foc_current sub-controller, which has worked really well in simulation
The problem is my AS5600 modules shipped with non-diametric magnets. I ordered more from multiple sources but shipping is slow in my region, and there’s no guarantee on whether those magnets are diametric or not. And I have a hard deadline 26 days out. Project must demonstrate working hardware on three independent axes (single-axis demo per motor is acceptable) or I fail and repeat the year.
I need advice or a plan that works with my existing hardware, assuming worst case where no working magnet arrives in time. Two options I’m considering:
Option A:
Change sensor to FluxObserverSensor, tune flux_linkage, keep foc_current.
My concern: my reaction wheels operate over a wide speed range including low/zero speed, where I read the flux observer is unreliable. Has anyone successfully used the flux observer on a B-G431B-ESC1 for an application that needs operation across a wide speed range including low RPM? How much tuning effort was involved?
Option B:
Drop FOC entirely, drive the motor open-loop at a commanded velocity. Outer loop on the ESP32 would output a velocity setpoint instead of a current setpoint, and I’d retune the attitude PID for the new actuator dynamics. Less elegant than FOC but no sensor required.
My concern: bidirectional reaction torque from a wheel running open-loop, is the resulting torque enough for attitude control, or is the commutation roughness going to dominate?
Are there any other sensorless options on the B-G431B-ESC1 I’m not considering? Are there any known sources of genuinely diametric AS5600 magnets that ship quickly? I’ve already been burned once on a non-diametric magnet sold as diametric :")
I’ll happily share my full firmware, Simulink model if anyone is curious about a similar application. Any pointers are welcome and appreciateddd, this community has been invaluable alreadyy
