So I hear … shame that is so … if it’s that obvious, it should be something that can be addressed.
I was more interested in talking about smaller planes without Vnav, but just Alt Hold & VS
I’ve just spent an hour watching twitch flight sim streamer Bish fly one of the business jets that comes with the premium deluxe version (forgot the plane’s name) and it had the exact same issue:
The issue manifested at 40000 feet. When he descended to 30000 feet the issue disappeared.
I am really not sure what you are hinting at, but…
Been trying out the TBM tonight and the AP have become very very abrupt or non smooth for the lack of a better term. Selecting VS up or down the plane reacts abruptly. The same in selecting alt hold, the plane jerks but holds that altitude. This was not the case before.
That’s the Cessna Longitude. I’m having that roll oscillation as well and have a thread in the bug forum for it. Haven’t tried the airliners, but I hear they’re all having the same issue as well. Looks like too much differential gain in the AP’s PID settings for ailerons.
Noticed this as well in the TBM. Looks like a case of too much proportional gain in the AP PID settings. Otherwise though, I haven’t seen the oscillations, so integral and differential gains seem to be good finally. It’s not perfect, but I can deal with that sudden change.
I haven’t really noticed any difference in the AP in the other planes as of yet, but I haven’t had time to really fly them other than short test flights.
They seem to have turned up the gain in the AP, and altered its PID, so its response time has been reduced by about 30%. Its faster, but still has the same damping.
This “should” be altered to match the dynamics of the plane.
In the case of the C172, its vertical stability oscillation is about 1 cycle / 10 seconds.
The #4 AP was about 1 cycle per 3 seconds
The #5 AP is down to 1 cycle per 2 seconds.
So yes, the AP will be more abrupt / jerky.
LOL so in effect "In terms that we ignorant simmer canUnderstand" , they have actually made it “Twitch faster, but with the same amount of Twitch”
Rather than just randomly adjust PID setting and see how the plane flies, it would be a lot easier & quicker to get these values closer with some Impulse Response testing.
Then take the plane for a final spin, and confirm it is operating as expected from your Impulse response testing.
The idea goal being close to the Center Graph- to Bottom Center
They have gone from Mid left to center Top. faster response, but still severe overshoot.
Well said. It’s been almost 25 years since I last looked at PID stuff, but I still recognize those curves and understand them lol. I think you’re 100% correct.
And on the Longitude and airliners’ roll, it’s basically top left graph but with lower proportional gain.
Well I have to say to all you guys above, you completely left me on the station with all the PID stuff, but one thing is for sure, having just paid 4.1m$ for my brand new TBM I dont want to bang my head in the ceiling every time I hit alt hold. Lol…
The difference is, when you bought your $4.1m TBM, when they installed the AP, they adjusted its response to meet the factory spec settings for that GPS, for that Plane.
They did not just throw it in and tell you to go fly it, and tell them what YOU think needs adjusting , nor did they give the Tug Driver “Dude” the task of adjusting it for you !
Nor did they try to Tweak it to compensate for that big 500Ib Tool box, you insist in carrying in the rear baggage compartment,
If you are using a controller go into the controller settings and under sensitivity set a deadline of at least 5%. You may need more just look at where the ball stops on the line after you move the stick. If it is still on the curve increase the dead zone if it is on the flat part of the line then you should be good. This won’t fix 100% of the issues but it should prevent most random turns in most planes.
I noticed a new behavior with the co-pilot. I tried the 787. It still doesn’t accurately follow the flight path, and now it rocks the wings back and forth. The descent and airspeed seems improved, but it still fails to initiate the approach or land. It just flies past the airport and keeps on going.
I also noticed some differences when trying to use the autopilot features in the cockpit (without using the copilot). LNAV seems to be much improved, as the plane accurately follows the flight path. Yay! But I couldn’t seem to get the autothrottle to work. It could be that I just don’t know what I’m doing - but with everything turned on and set, the plane would continue to accelerate or decelerate past the autothrottle settings as though it wasn’t turned on. Also pressing VNAV caused wild erratic behavior, pitching the plane at extreme angles.
Other glitches from previous updates are still there, including multiple legs flying back and forth to the same waypoint on the VFR map, co-pilot just flying off in random directions, just to name a couple.
Next I’ll try clearing the cache and community folders to see if that makes a difference.
I am wondering what happened for them to delay 3 days the update. They said they had found something in the AP, but it keeps working bad. I feel the AP wants to kill us.
It stands for Proportional Integral Differential control. It’s basically how pretty much every dynamic closed loop system is controlled based on a measured input signal. In very basic terms, the 3 parameters dictate how much control signal is applied to a system, how fast it’s applied, and how that control signal changes over time as what you’re trying to control reaches the state you want it to be at (equilibrium).
