Throttle lag

[Timboj]

Hi guys, what setting should I be looking at that's causing the delay in my throttle closing?

It's felt most in circumstances like the second instance where I'm off throttle and clutch in but the revs continue to rise because the throttle stays open momentarily.

There are plenty of examples of the throttle following the target pretty closely in terms of responsiveness so my assumption is this is a setting.

[aerace_fab]

Dash pot settings is the first place to look. 

Share your tune file and a log file to better help out. 

[Timboj]

Dashpot doesn't appear to be activating around most of the instances in this log:

https://drive.google.com/file/d/1BAWqB2atEgnuyxi15vn1ulBy1J_kTi_0/view?usp=sharing, https://drive.google.com/file/d/1tOesf1BAuMzpr_5C4FXJku7h9w1c1_G8/view?usp=sharing

Example- all under RPM lockout condition:

[Adamw]

It appears to be mostly due to the idle position being close to the spring balance point for the throttle, so anytime you want to move above of below that a small amount it takes time for the closed loop integral to wind up to the large change in duty cycle needed.  

I would try doubling the current Integral gain in E-throttle settings and tune the feed-forward table.  Something like below would be about where I would start.

[Timboj]

Thanks Adam. I'll give it a shot.

[Timboj]

That's night and day @Adamw, thanks. For what looks like such a small change, particularly low speed gear changing, it has drastically improved the feel. It had gotten to the point where I thought I had some slack had been introduced into the drivetrain (but suspected it could have something to do with the tune) because that unresponsiveness was manifesting into engine speed undulation.

 

I could probably live with the config you've given me but how do I approach adjusting from here? In this example here do I dial back the 20% feed forward?

 

Or in this case, add some to my 4% (-15) cell?

 

 

Just want to understand how to interpret the data.

[Adamw]

If you set the PID setup to "E-throttle 1" then you can view/log the feed forward, P,I, & D that was working at the time to see where the overshoot is coming from.  I would generally look at "E-throttle 1 Motor DC" to see what DC is required on average to achieve a specific TP and use that for your feed foward.  You will notice there is a very large change right around the point where the motor force changes from pushing against the spring to pulling against it.  

I suspect your little overshoot may be improved by increasing derivative - I often end up maxed out at 65 for D.  

[Timboj]

@Adamw It's been slightly improved (larger overshoot/undershoot has been reduced) but I've noticed a lot of noise on the throttle position, and it's definitely noticeable in the rpm:

 

I assume it's the PID settings but I'm still wrapping my head around them...

Log and map:

https://drive.google.com/file/d/1GSQJJS7pe6VLhOybz0W_WHIXcemPYYaG/view?usp=sharing, https://drive.google.com/file/d/1YpblaNe9HfRxCbb5OEkzmDKGSZfepjdR/view?usp=sharing

[Timboj]

Any chance you guys could chime in on this one? Should I read this as reduce the proportional?

[Adamw]

Your throttle looks to be controlling quite well in that log, I doubt you would be able to feel the +/-0.1% movement in most conditions.  

I would think the lambda target of 1.1 in that cruise area would more likely be the cause of any surging or torque variation you can feel, you will need more like 45deg ign advance and nice big spark plug gaps to run with stable combustion at 1.1 lambda.  

You can possibly slightly improve throttle control with the latest firmware, released a couple of days ago.  In FW6.25 a user-configurable deadband has been added to the E-throttle control which will quieten E-throttle movement down when it is close to target.  0.05 - 0.10% has worked well on the couple of engines I have tested.  Also in 6.25 the max limit on E-throttle derivative gain has been increased so you could try also bumping the derivative up to say 80 which has resulted in improved stability on some problem throttles for me.  

 

[Timboj]

Cheers. I'll give that a go. And lower my lambda a touch