I’m running v6 float package and on curb drops if I don’t land directly over the tire, the board trotters and it sketches me out. Right now I can’t accelerate into a drop, or do that little nose push thing on slow drops to clear the tail because the nose will dip. What setting should i mess with to fix it?
Definitely experiment with Rate P! This accelerates the board based on the nose’s angular velocity, rather than the angle itself. It allows those quick pushes you’re thinking of, as well as dampens harsh teetering movements. The default value of 0.6 really should be solid for this purpose, but I’ve experimented with values like 0.8, 0.9, and even a bit higher, though higher can start experiencing negative side effects.
If you’ve changed things beyond default, including an XML of your current settings really helps for questions like this.
You called it. Increased Rate P from 6 to 7.5 and decreased Angle P from 20 to 19. That was able to fixe 80% of the issues. Will continue to experiment with PID to get it dialed!
I think most of my tuning are still on default values, except for mahony kp 2.3 (from 2.0) and booster is 8, 4, 40, field weakening 30, 65, 500, 2
My specs is stock XR battery no BMS
For reference I’m 200lbs, maybe that has something to do with the board needing more Rate P on drops?
ok on curb drops it feels mostly ok, as long as I land reasonably balanced (still not as stable as my FM boards but good enough).
But on repeated drops like stairs that last little bit of sketchy-ness really adds up. There is a flight of stairs, like a series of small drops (8x 7cm drop every 1.5m ish), that’s throwing me. On my current vesc tuning it just nose dips and taildrags like crazy. I’m running 1/4in lower tfl center steez on my vesc but I can’t imagine clearance or skill being the issue since I was able to clear it on my 1/2in lowered GT consistently and easily. On GT I just lean forward heavily on repeated drops and the board handles the rest with minimal tail drag.
I experimented with PID and Filter but couldn’t get the desired results. I’ve attached my app and motor config.
vesc_appconf.xml (11.8 KB)
vesc_mcconf.xml (10.4 KB)
Can you include your Float Package XML? Your app and motor configs don’t tell us much.
oh sorry, here!
vesc_floatconf.xml (3.5 KB)
I don’t think this is the primary issue, but if you’re concerned with tail drags, I probably wouldn’t use Brake Tilt. Maybe leave the strength at 0 for now, unless you really need it to get the ride feel you need.
For your IMU settings, there’s a few things. First, I noticed one of your Gyro offsets is very extreme, which seems odd. I would go to the IMU Wizard and do the Gyro calibration step. Make sure they all stabilize before saving. If you were already perfectly calibrated, these should all read near 0 for the offsets before you save, but I have a feeling this is not the case.
Other things I would try is maybe giving Accelerometer Z Low Pass Filter of 1Hz instead of 2Hz a shot. I haven’t had too much of a chance to test myself, but I’ve heard it actually works pretty well and delivers better results without negative side effects so far. I also have an Accelerometer Confidence Decay of 0.02 instead of 0.01, though I don’t think this would make any noticeable difference.
Last thing I would consider is calibrating the Accelerometer, which you haven’t done. Most IMU’s don’t need it to perform well, but it’s definitely worth doing if you’re getting weird behavior, as it could cause the kind of drifting you are describing. You can do so either manually (https://youtu.be/XacXjwFKKF8?t=347), or using the Accelerometer section of the IMU Wizard, which is basically an assisted version of the same process so that you don’t have to look at graphs. Wish I had a good video showing how this is done, but unfortunately I do not yet.
It’s definitely better now after trying out the settings you suggested, but the nose still dips a little when I accelerate into a drop, and when I land I have to intentionally press the tail down to prevent the nose from hitting the ground. Also maybe this is a related issue but when I do a regular to fakie front side revert on my vesc, I have to put a lot of weight on the battery side of the board, where in FM boards more weight should always be put on the controller side. If I revert the way I do it on a FM board, the vesc will nosedive as I revert. Regular to fakie reverts have always thrown me off when switching back n forth between my vesc and my FM boards. Maybe this is a tuning issue related to the nose dips on drops?
Example of nose dip on drops (0:21): Riding my VESC in NYC (w/ commentary) - YouTube
Can you take a look at my settings again plz. Here are the key updates:
- Calibrated my gyro and accelerometer to the best of my abilities
- Tried both 1Hz and 2Hz for Accelerometer Z Low Pass Filter but I can’t really tell that big of a difference.
- calibrated orientation to level out my w rails
- tried turning off brake tilt but I really don’t like how it rides. can’t press tail down for nudges and bonks
- found out that my motor crunch was caused by Motor/FOC/General/Motor Inductance(L) being out of reasonable range from my calibration. still have a bit of crunch on extreme braking on w rails but it’s better now
Thank you for your help!!! Generally I’ve been loving my vesc and have been posting yt videos on it now.
Did you find the solution for your nose hunting off curb drops? I am playing around with a mate’s board who is doing the same thing whereas my original focer running 5.3 did not have this problem.
I did not find a solution, but I heard from a fb chat that dado said this is normal for focer and there is no fix… would be great if someone could verify
I’ll add my two cents since I have been working on the code lately. The example in the video at :21 is a really good footage for this issue I think. It looks like the board lands fine but then nose dips maybe 200ms after the landing. It’s it odd that this does not happen for all boards and i have not had this problem personally.
This could be a fundamental issue with the mahony filter and the IMU but I think it might be simpler than that. The first thing I would do is disable anything that can change your setpoint. I think a fix for braketilt strength just got implemented so update your package. Confirm while you are riding that AppUI setpoints are not changing. Then see if you can repeat the issue. This would help narrow down the cause.
There are a couple reasons why I think a setpoint change might be the cause of the issue. When you accelerate off a curb you are likely to engage the “running wheel slip” condition. In this condition any setpoints your board has off zero degrees pitch will be reduced by a couple percent every 1.2ms. Then once you land the wheel slip condition stops and normal setpoints can reengage.
I see you have ATR strength of 1.5. When you land from a curb drop your wheel acceleration can change suddenly causing ATR to change your setpoint suddenly. In combination with the wheel slip condition which temporary dampens the response, this might cause the setpoint to engage quicker then expected.
A possible fix for this could be modifying the ATR biquad filter rate. I believe a lower frequency dampens the reaction. I have also found the combination of high ATR strength and max angle can be problematic for street, but works fine for trails. You might consider either high ATR strength or high angle but not both for street riding. Just my personal feel on it.
Finally, if you can capture some RT data, I find that can be helpful in adding another perspective to what is going on. Not too much data though. It has to be zoned in on the problem or else there is too much data to consider.
Just got my vesc’s up and running and plan to get you some data shortly, if your still interested, as this is occurring to me with the standard float package settings.
Would be awesome to get this sorted as my nose has hit the ground multiple times after accelerating into curb drops.
update for anyone still running into nose hunting:
- disable all tilt settings in float pkg (ATR, turn tilt, variable tiltback, constant tiltback)
- make sure sensorless ERPM is set at 2000
- use dado’s recommended motor config settings How To Configure Motor
- calibrate IMU / accelerometer
- loop hertz is set correctly for your hardware. 832 for focer 3.1, 800 for everything else (i’m pretty sure…? but check the docs on the manufacture’s page for specs). There is more than 1 place to set this, in float pkg specs page, also in app config > IMU > sample rate
- zero vector frequency has a huge effect on board stability. Ubox defaults to 30khz, I’m currently running 22khz and the difference in stability is night and day. FM hardware I think is set to ~14khz. Don’t copy my setting but instead play around with this value until you find a good tune. anywhere around 20k-30k should be acceptable. The most consistent test I found for troubleshooting nose hunting is going over chunky cobblestones.