I have been working on a quadplane project for the past few months with mixed results. This airframe is a 3 meter wing span custom design flying wing weighing between 12-15kg. I started off with a quad setup for the VTOL capabilities. I had some very unfortunate problems with the quad motors and ESCs though which led me to the decision of an X8 configuration. I loaded the latest Copter X8 firmware and started testing without the wings attached... all was well and I was able to tune the setup well and had good results. I then loaded the latest Plane firmware, leaving Q_Enable at 0 I bench tested the plane equipment and all seemed well. Then, I set Q_Enable to 1 and copied over the X8 PID settings. Once changing the Frame configuration to Octaquad (3) all kinds of things were screwed up... The plane motor esc was no longer receiving a PWM signal and the control surface servos were acting very strange, humming and moving on their own regardless of flight mode. The octa motors did however work normally. I tried plane firmware from 3.5 all the way to the latest 3.7 with the same results. I just loaded the beta 3.8 rc5 and this problem went away. All systems work properly. However, the motor mapping on the octaquad configuration is not right.
I setup with octaquad motors as suggested in the wiki:
Ch5 = motor 1
Ch6 = motor 2
Ch7 = motor 3
Ch8 = motor 4
Ch9 = motor 5
Ch10 = motor 6
Ch11 = motor 7
Ch12 = motor 8
I have the ESC labeled by location, not # to make things easier.
Ch5 - motor 1 = Front Right Top
Ch6 - motor 2 = Front Left Top
Ch7 - motor 3 = Rear Left Top
Ch8 - motor 4 = Rear Right Top
Ch9 - motor 5 = Front Left Bottom
Ch10 - motor 6 = Front Right Bottom
Ch11 - motor 7 = Rear Right Bottom
Ch12 - motor 8 = Rear Left Bottom
When I use the motor test menu, these are my results:
A spins motor A
B spins motor E
C spins motor F
D spins motor C
E spins motor G
F spins motor B
G spins motor D
H spins motor H
I was able to switch inputs around until A=A, B=B and so on but the mapping is still messed up in the firmware. Control inputs don't match motor outputs.
I checked the RC outputs to verify their channel mapping and they seem accurate:
Rc5 =33
Rc6=34
Rc7=35
Rc8=36
Rc9=37
Rc10=38
Rc11=39
Rc12=40
Does anybody have experience with this, or any suggestions on how to fix this?
Thanks,
Chris
Replies
FIXED!
I uploaded the latest beta firmware 3.8 rc6, then figured out that the Frame Type number is off by 1.
Frame Type:
0 = Quad
1 = Hex
2 = Octa
3 = Octaquad
4 = Y6
The actual correct type identifier for Octaquad is #4. Once I selected this, everything worked fine and I was able to complete two successful hover tests.
Parameters
UAS003_OCTAPLANE_7_5_17.param
After some creative motor mapping, I was able to have all channels working properly.. or so I thought.
I bench tested and everything seemed fine but its hard to tell while the aircraft is secured down. I took it outside and attempted a hover in QStabilize. Throttle, roll and pitch seemed fine but Yaw was not. I added a touch of right rudder and the plane yawed to the left and tried to flip over the nose. Not sure what this means other than there must be a mapping/control output issue.
If anyone is curious or has some suggestions, please advise.
Here is my param file.
I just found some more information over on arudpilot and it seems that a couple people are having the same or similar problems.
http://discuss.ardupilot.org/t/quadplane-octaquad-servo-buzzing/111...
Any resolution to this?