CURRENT_SENSE_SATURATION at lower current than expected

Hi everyone!

I am using 56V ODrive V3.6 to control two Turnigy Aerodrive SK3 - 5045 - 500 KV Brushless Outrunner motors ( with E3 Optical Kit Encoders (E3 | US Digital).

When using either one or both motors, the ODrive will throw an ERROR_CURRENT_SENSE_SATURATION and sometimes an ERROR_DRV_FAULT when the current nears 35 amps with trap_traj position control.

Here are some of the current ODrive settings (Full motor.config dumps below):
current_lim = 55
current_lim_margin = 5
requested_current_range = 120
calibration_current = 16
dc_max_nagative_current = -55
current_control_bandwidth = 2000

Motor 0 Tuning:
pos_gain = 19
vel_gain = 0.135
vel_integrator_gain = 0

Motor 1 Tuning:
pos_gain = 19
vel_gain = 0.0845
vel_integrator_gain = 0

Appreciate any ideas you have! Thanks!

Hmm, what CPR encoders did you get? Everything else looks fine. 0 vel_integrator gain is weird but should work just fne.

I believe that the CPR is 4000, but I will need to double check that after Thanksgiving. Would an incorrect CPR be able to cause this issue?

The vel_integrator gain is 0 because I wasn’t able to get the liveplotter working at the time of tuning. It works now, but I haven’t gone back to update it.

After double checking: The Cycles per Revolution of the encoders is 1,000 and the Pulse per Revolution = Count per Revolution is 4,000 (which is what the CPR is set to).

Additionally, I have raised the vel_integrator gains based on the instructions in the documentation (0.5 * bandwidth * vel_gain) after finding a bandwidth of around 200 Hz (5 ms settling time) from the live plotter

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This sounds to me like it has something to do with the current controller, but that can be influenced heavily by the encoder. What do you have set for the encoder bandwidth?

Currently encoder.config.bandwidth is set to 1000 for both motors. I don’t believe those values were changed from the default.

Just wanted to provide an update:

We had been using a Valefod LM2596 DC to DC Voltage Regulator to step down two 4s Lipo batteries to 25 volts. We didn’t realize that the Voltage Regulator had a low max output current (documented at 3 amps). After switching to a single 6s Lipo and not using the regulator, the ODrive appears to be functioning as expected!

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