@zhangsir I must say I enjoyed your description!
And I also must say this was a community effort project between myself, @bnsgeyer and @Ferrosan to make acro more suitable for helicopter and not so “lame”. The more direct stick-to-swash “feel” without the robotic stop-turn-go stuff makes it a pure pleasure to fly with a natural feel that a helicopter should have.
To get snappier handling in the pitch and roll and adjust yaw, adjust the following to your preference
And if you run up against the acceleration or rate limits adjust these:
To adjust the rate of decay (changes the “feel” of the virtual flybar) adjust these.
This new mode also makes it possible to fly the helicopter with the EKF blown. Tested here, and it works fine. It is only loosely connected to the attitude controller’s attitude solution. Since it constantly decays to actual attitude, it doesn’t really matter what it “thinks” actual attitude is. So it provides flybar redundancy for a FBL helicopter and when I blew the EKF, other than the ground station complaining about it, I could not tell it in the way the helicopter flew.
Other features of it - slope procedure is a piece of cake. You can hold constant cyclic pressure into the hillside just like a real one, and it won’t build up the rate command and tip your helicopter over. No more goofy nudge and center the stick and see what happens. The pilot actually has control of the machine the way Igor Sikorsky intended for helicopters to work.
In the end, getting it to work was a relatively simple thing. But it’s still a masterpiece and it took a lot of flight testing before I was happy with it. It has since been PR’d to master, but not merged (yet).