Little more feedback. I would say flying around in POS HOLD is not a good experience (wishy washy) with PSC_ACC_P & I down at 0.1~0.3 range - suggests I may have been correct about the controller not happy with values below it’s hard 1.0 lower limit.
Yeah, I’ve had another go at it and pushed PSC_ACCZ_P as hard as possible and the thing is definitely better. I can only get up to 0.30 but it’s so much better than 0.185 I ended up with before. (added some D also , but I don’t think it does much)
I think someone needs to take a look at that controller as my conclusion is as before - It’s just not happy with low values.
Quad does sink occasionally in ALT Hold but has not hit the ground and goes back up again now
I’m afraid we can’t let comments like, “EK3 is broken” just slide by without some better description and analysis. Have you got an onboard log?
I fear what is happening is various parameters are being changed at the same time without much understanding of what they do. I really think to get the best outcome a more methodical approach is required involving:
clearly stating the issue & providing a log demonstrating the issue
analysis and suggested param changes (by the likes of @andyp1per and I)
implementation of those changes and re-testing
… and then we repeat this iteratively until we get it flying better or we come up with code issues that need fixes or enhancements and/or improved documentation.
Randy, That’s off topic and emotional - You have no idea how much you have pissed me off!! and certainly not half a clue to the amount of time and effort I have put in to giving you some accurate quality feedback.
This has a lot to do with the size of the aircraft. Andy uses very small aircraft where I spend most of my time with medium sized aircraft. We attempted to drop the default filter setting to 10 Hz but too many people needed to adjust their Alt_Hold tunes. I run with 10 on all aircraft because I don’t need the responsiveness and expect alt hold to be accurate and smooth to minimise interference with the quality of the attitude hold. But this does require slightly lower pid values on PSCZ.
I find the instructions on the tuning page work very well for all aircraft. Andy does not need his filters set this high. He has a tendency to take all his filters as high as he can but this is not necessarily the best thing to do for overall performance. This is why I said I run 10 Hz on all aircraft.
OK. This for example. The craft flies well generally but the commanded motor output at forward speed is oscillating and bouncing off of Motor Min. Is this a attitude control issue, a PSC Control issue or is it simply high thrust to weight and hard to tune? There has been quite a bit of forum activity around this recently.
It looks like the attitude controller is oscillating. If it wasn’t for the protectins in the attitude controller and motor mixers this aircraft would simply crash on take off.
The reason for the difference in defaults to what I recommend is because if we set my recommended parameters as defaults anybody who has not changed the defaults already will find their parameters change.
So when you upgrade if you have not changed a default value and that default value changes then you get the change. So in order to not risk messing up peoples tune I have to suggest people change the defaults.
For example, when we reduced the default IMU ACCEL FILT default to 10 a bunch of people started see oscillation in Alt Hold. So we had to move it back to 20 Hz. But this didn’t change my recommendation to set it to 10 Hz.
That is exactly what we need - I don’t want to say most of the settings do nothing but that is what I found, certainly with PSC_ACC_P &I down to 0.1/0.3 range the controller does not seem too.
With more interest in smaller craft maybe a look into how this controller scales is needed.
At least then anyone putting the time and effort in tuning would be able to feedback which settings do little.
The problem here is that most users do not understand this image:
So if people don’t understand the impact of filters on a PID loop, and they do not need to be changed from the defaults, then it does not make sense to talk about them in a tuning guide. It would serve as a distraction to more important parameters.
I am building up diagrams of the control loops in the 4.1 release that we will make available on the wiki for people that do have an understanding of guidance and control. So I hope that will fill that small gap.
In this case I think your comment is what I expect most users to experience:
Reading through this I think the working at the end could be improved:
“AltHold starts to move up and down the position and velocity controllers may need to be reduced by 50%.”
This could be interpreted as gentle slow movement when it is referring to vertical oscillation or maybe fast bouncing. People may be interpreting poor alt hold performance as “movement up and down” and then reduce these parameters making the problem worse. So I will fix this.
@Leonardthall
Well all I can add is the Alt and Position controller do not work properly for me then.
I understand what filters do and I’ve opened them up and closed them down, Think I also mentioned I have to push PSC_ACC_P&I close to Oscillation to get anything better than Altitude hold not even using ALT or POS Hold controller !!
The Only thing I did not do was try the filters with PSC_ACC_P&I in what I feel is a range the controller starts to work properly.
I think we are not going to get anywhere with this until You or a Dev has a little Copter to try yourself.