I have also wobble problems at speed and it could be the FW4.0 because I tried everything else to solve it without success. It always happens between 44-46km/h (27.3-28.6mph). Setup: Vesc6, 220kv, 1:6.25 gearing, 9".
I recorded some log files and recognized that the duty cycle seems strange. When the wobble happens the value jumps around. Blue line is speed an pink duty cycle.
Sounds like you hit the max erpm programmed into the tool. I did also notice that Ack firmware is super smooth with that, and the 4.1 is very abrupt when you hit top speed it jerks around a lot.
I think the reason I’m not noticing wobbles — but I notice the very jerky max erpm backoff — is because I’m using single drive.
It looks like when one motor backs off, it speeds up the other motor because of the way the trucks are, which then causes that motor to back off and the other one reengage (because it’s now slowed down a tad) causing a feedback loop.
That’s my hypothesis, anyway.
BTW I’m using Control Mode: Current Hyst Reverse With Brake
One more vote for something ERPM related, since there isn’t any tuning of the speed PID for each specific board this looks exactly like and overshoot and over correct while being under dampened
@Trampa I’m a big fan of having specific real world examples of points I’m trying to make. This is one of those very examples.
Do you recall a certain stable/unstable discussion recently and how the lack of a dev/stable cycle can be problematic?
You have multiple users, including @rich (whom I’m particularly fond of thanks to his sweet choice in hubs and also greatly trust his experience/insight), reporting issues.
This is going to happen. It’ll keep happening. It’s part of hardware development.
Which is exactly why it should be happening as an opt-in dev branch so users have visibility & choice.
This is my first foray away from the rock-solid @Ackmaniac code, and only for the HFI feature. Which, by the way, is a new “essential feature” on any of my skates
