(PROBLEM) Skywalker X8 waveing during flight in AUTO mode

Vito

Hi guys,

I have problem with navigation of my Skywalker x8 in AUTO mode. As you see on the picture below, the plane cant fly straight between waypoints and also makes unnecessary turnings. I am using mission planner ver. 1.3.44.

First I tought the problem is with navigation tuning and tried to change some parameters, Here are the parameters from which I started:

NAVL1_PERIOD 22
NAVL1_DAMPING 0.8
RLL2SRV_P 1
RLL2SRV_D 0.02
RLL2SRV_I 0.04
PTCH2SRV_P 0.65
PTCH2SRV_D 0.02
PTCH2SRV_I 0.04

After that I tried to make some changes in the values but it didnt help. Do you have any idea which parameter can cause this issue? Some other parameter what I didnt change? Or could it be something else like compass error? The plane is flying well in manual and FBWA modes. I will appreciate any help!!

Skywalker x8 waveing problem

I also uploaded the logs to google drive, here is the link for download:

https://drive.google.com/file/d/0Bwtgo0Y55BmmQmQ0TldiNFZsVzA/view`

Sinamics

Hi Vito
I will check those logs later today. What type of Flight Controller did you use?
I have flown many X8 using Navio and Pixhawk without any issues. X8 flies great on standard PID`s. Normally when you have an error like this its caused by either:

GPS sat count
Compass error
Compass position is wrong. (Arrow not poiting forward)

Does the X8 flies great in Normal mode? COG is correctly adjusted?

Vito

Hi Sinamics
Thank you for your interest to help me, I am using APM Plane Pixhawk with latest firmware 3.7.1. The plane flies absolutely normal in manual and FBWA mode. When I am changing PIDs and NAVL1_PERIOD there is only difference in wave amplitude lenght.
I am going to try calibrate compass and adjust COG again. I am just also wondering if that problem can be caused by elevons, I am using this configuration: elevon settings

Could you send me your telemetry log? I would like to review and use all your parameters from that log. Thank you again!

kevinfjj

Sinamics
Hi Sinamics
I am new to RC plane and i am planning to fly the Skywalker x8 using the Pixhawk cube. However, i am not sure what Parameter should I go for, such as the initial PID values in the controller. I have tried to use the Hardware-in-the-loop to obtain the PID gain by autotuning the X8 but i failed to do. So i am wondering do you have some suggested value or flight log that i can analysis in Mission Planner. Thanks in advanced.

Sinamics

Vito
I agree, the Auto mode is terrible... I will look into the logfiles and see what i can find..

image 2017-03-13-17-35-42.png

Sinamics

Vito
Are you sure your yaw / rudder is compensating the correct direction? Seems like the rudder is working 100%

image 2017-03-13-18-06-34.png

When banking the aircraft left, the rudder should go right to keep the nose up. I could imagine if the rudder is reversed that this behaviour could occur.. Just a tought 🙄

Could you post your .tlog file as well?

Your Servo connection seems fine.
Have you tried the AutoTune function.. I did that on my last X8, and worked like a charm.
I dont have any fresh configuration file, as my last X8 flight was a while back.

vibmad strange behavior..the wrong COG won't do that

Agree.

vibmad

strange behavior..the wrong COG won't do that but more like going up & down and accelerating with no reason but not turning like that ? what about AHRS error ? or error compass variance ? sometimes once on the air gps has some glitch and dsiplay a message on MP ...make sure to put away the raspberry / 4g stick away from GPS ....

Vito

Sinamics

Here is a telemetry log from that flight. Sorry, I forgot to attach it before. Thank you for your help!

https://drive.google.com/file/d/0Bwtgo0Y55BmmdTBOUkZTdWM4b0E/view?usp=sharing

Sinamics

Vito
Your target roll versus actual roll is way off, that makes me think its related to PID.
Try AutoTune next time. It worked for me on a X8. 🙂

image 2017-03-13-19-34-55.png