SK450 Dead Cat - PID tuning advice sought

I'm trying to figure out where to go with my SK450 "Dead Cat" build. I have it flying, but just barely and very difficult to control. Here's what I've got - I'm willing to try other hardware, but I'm hoping someone can give me some advice to get closer than I am now to making a flying machine that I can use. Eventually, I hope to mount a camera, but not until I can fly it quite a bit better. I've been and will continue to experiment with PID values, but am not sure if I'm wildly off in some critical way, so I'm asking here for advice.

Here's a video of what it looks like when I try to fly it (it's ugly) with "Angle" mode enabled: http://vimeo.com/79695015

The build:

SK450 quad with "Dead Cat" conversion

Motors: NTM Prop Drive 28-26 1000KV / 235W

Props: 8045 (carbon fiber)

Controller: MultiWii 328P Flight Controller with Blutooth module (ACC/GYRO/BAR/MAG)

ESCs: TURNIGY Plush 25amp Speed Controller

Battery: Turnigy 2200mAh 4S 35C Lipo Pack - 257 grams

I have some lighter 3S batteries as well, and some 1045 props I can work with. I'd eventually like it to carry a camera mounted on the forward platform that weighs 165 grams. The present total weight of the quad with the 4S battery is 1290 grams.

Here are the current PID values (In P, I, D ordering):

Roll: 2.5, 0.030, 23

Pitch: 2.5, 0.030, 23

Yaw: 5.5, 0.045, 0

ALT: 7.1, 025, 24

Pos: 0.10, 0.0

PosR: 2.0, 0.08, 0.045

NavR: 1.4, 0.20, 0.080

LEVEL: 9.0, 0.010, 100

MAG: 4.0

Thr Mid: 0.30

Thr Expo: 0.00

RC Rate: 0.94

RC Expo: 0.81

Thr PID attenuation: 0.00

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Replies

  • Based on the sounds in the video I think you have a fast oscillation problem.  Your P terms are probably too high.  How does the quad fly with the default settings?  

  • I had/have a similar issue with my KK2.1 controlling my deadcat (alien/reptile)  And I got the same amount of support that you have.  

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