I have a racer that I’m trying to tune with Ardupilot.
I have tuned filters and harmonic notch based on ESC telemetry.
I fly the drone on Stabilize mode and defined 78 deg angle max.
On slow speeds and punches it feels pretty good, but the problem is when I want to make a fast straight line and push pitch and throttle to the limit, it seems that it starts it good but after a sec the pitch becomes sluggish and exceeds the angle limit down and pitch back up.
Does someone can help me figure out what I might do to fine tune this?
Looks like you’re hitting the limits of the motor outputs so there’s just no control authority left. You might have to start trying some different props to get more high end speed. I know @dkemxr has done some fast builds, maybe he has a suggestion.
Yea, @Allister has it right, you need higher thrust/weight for greater expectations. A hover throttle (Tho) of ~0.2 is fairly sedate for a Racer and because the Outputs are maxed out it’s not reaching max pitch and as he says Attitude will be compromised. It won’t matter at this point but tuning can be improved if you did gain more thrust as you have a few at default. Not sure what is going on with your battery monitor and no GPS for a indication of speed.
Building and tuning for max speed is a deliberative process. I did it on a few quads for max Auto Mission speed (search that on the forum) but it will give good performance in any mode. You should also review Andy’s 7" Long Range Blog post and video’s. He’s built and tuned for max Acro performance.
Just noticed one parameter that is way off base. 12Hz for the Gyro filter is way too low for even large craft let alone a Racer (fat fingered 120Hz?). And your notch filter settings and some related parameters (loop rate) leave much on the table.
If he had used the ArduPilot Methodic configurator, and would have posted the files, it would be a lot easier to help him. Plus he would need a lot less help, because he would be able to help himself.
Thanks for reply @dkemxr
So is there a way to limit throttle? in order to leave some power for the motors for attitude control. I want to just push the throttle stick till the end instead of being aware during flight where is my throttle stick, I couldn’t find THR_MAX in the parameters.
About the Gyro filter I will try to raise it as I noticed that when I put it on 24hz I had already oscillations. About notch filter, configured with ESC Telemetry over DSHOT, I took the strongest spike ok hz I saw in the batch sampler and put it in the INS_HNTCH_FREQ, seems that it filtered it pretty well no?
Would you use second notch for the spikes at around 350hz or the RPM filter does it by itself?
About loop rate as I’ve read it suggested to leave SCHED_LOOP_RATE at default of 400, it’s written that above it is for dev. do you think that it might help to raise it? how it works actually compares to Betaflight?
And my drone is 10" big racer with 8s battery and Matek H743 Slim V3.
That parameter hasn’t existed in years. You are on the wrong track with a throttle limit. Of course you can just reduce the angle_max parameter to something more reasonable for this craft.
But I think you should start over with a standard tuning plan. It could be The Configurator that @amilcarlucas linked to or manual tuning if you know how to do it. But this craft wasn’t configured with the proper Initial Tune parameters to start with.
Also, we have new tools for viewing Notch Configuration. Nobody uses Mission Planner for this any longer. Filter Review Tool
You can use it to predict a good config. Don’t be fooled by yours though because of the 12Hz Gyro filter. That will make anything look flat… This should be set to 42Hz to start BTW.
