@SkaterBoy58 i think this fix is a bit out of my wheelhouse. @mmaner?
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The post was deleted so I don’t know.
He’s not complaining about the torque of his brakes. I’m having the same issue since updating to the latest firmware. Brakes are fine, then i get to about 2-3 mph and the motors lock up. It has nothing to do with releasing the break trigger… The max ERPM setting needs to be exposed for FOC, its as simple as that.
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These two topics should really be merged
I’m experiencing this as well on my new build. 6355, focbox, FOC, 16/40 belt. Slowing down/stopping from any speed above around 4mph is smooth - all the way to stand still. Anything below 4mph and it doesn’t matter how gentle I am on the brakes it just locks up and jerks.
Manageable but annoying. I’m using ackmaniac, has anyone found a solution other than editing the xmls yet?
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Editing XML didn’t work for me
Well that’s wank 
Yup I am subscribed to all these; hopefully a fix come about. It is present on all my builds. All ack firmware FOC sensored.
10s6p on 107s with 18/40 12s5p on 6shooters 20/60 6s3p on 83s with 14/36
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Still hate this “handbrake” thing.
Just set up my first FOC build and am joining this club. If anyone has any resources on exporting, editing and reloading an XML file with the VESC tool I would appreciate seeing them before I give it a shot.
In the PID Controllers section, reduce the value of “Minimum ERPM” and see if this fixes the problem. This value is used while braking, and if the current erpm is lower than this value, it switches to “duty cycle” mode and sets the duty cycle to 0 which I think causes this sudden sticky stop while doing low speed braking… Anyway, made it a lot better for me when i reduced this from 900 to 300, so you might wanna give it a try
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Where does it switch to duty cycle mode?
Doesn’t that just switch according to some hard coded 0.03? s_pid_min_erpm doesn’t get touched unless you’re in speed control.
Still no solution to this?
Mine was slightly lessened when I changed from a 15T to 18T pinion… But it’s definitely still there.
8" wheels on dual focboxes.
This was also being discussed over here. @Deodand said he was going to look into it but I am sure he will be way too busy for while.
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I wonder if you could just lower the hard coded value in @tsr 's codeblock. If the controller isn’t actually losing sync, then brakes would be fine.
anyone willing to test? risk of losing brakes at low speeds
Hey! Thanks so much for the advice. I have been messing with that value and it a lot better. Still not perfect, but I feel a lot more comfortable coming to a dead stop now. Thanks for taking the time to reply and share your knowledge.
For anyone else looking in on this, I run 100mm wheels and have set it to 450.
This is on my todo list, FYI in FOC the setting described doesn’t do anything it is used in BLDC only. That hard coded value of 0.03 is a percent duty cycle (3%) and when your motors get there the controller in braking switch from current control to duty cycle control and this causes the dramatic transition
I know the problem and am working on a fix but with everything going on it will prob be a few weeks out.
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