MultiWii / NAZE / SP Racing F3 HK MultiWii Mega Board w/ MTK 3329 PID Tuning

[HighFlight2k2]

This is my first DIY quad. I have an mqx that I learned on. It has been an experience for sure. I have it flying after working through several "noob" issues. But I can't seem to get it to fly any where near as well as my little mqx.

Hobby King X650F frame (CG'd dead center)
MultiWii 2.3
11x4.7 props
750kv motors
3s 3000 40C batteries

I have sync'd the ESC. Props are balanced the best I could. I have covered the board with open foam as I read that helps the barometer. ACC and MAG work fine on the bench. They are very steady and MAG is on the money. Barometer, however, is not. It fluctuates +/- .75. GPS currently isn't sending a signal but didn't think that mattered. I have no hold options selected as of yet.

With the default PID settings (3.3/.030/23 for roll and pitch and 6.8/.045/0 for yaw) it will hover but after a few seconds wobbles uncontrollably and crashes. I tried lowering all of them to close to zero and I was able to get it to fly better, but any stability is at the pilots discression, not the on board brain.

Is there a rule of thumb for setting up the PID? One tutorial I found said to start with P and I at zero and work with D only at first. Then introduce P and I back in. I want to make sure my approach is sound. Also, that my setup is good.

Any advice is greatly appreciated. I am working in baby steps but my goal is a good camera and fpv platform. It seems to have plenty of power to support the added weight.

Thanks very much!

Jon

 

[mattjb]

I'm in the same predicament as you. I have had mine flying but it drifts A LOT!

I've seen quite a few videos on "string tuning" quads to get an idea of where the PID should be. Seems a good place to start (although requires a fair bit of work to set up securely). You don't mention what ESCs you are using and if so, what firmware they are running too. That could help.

I think my problem at the moment is crappy motors (NTM 28-30 from HobbyKing). Going to invest in some better quality motors soon, and try setting up again.

After that, time to try a different controller.

 

[HighFlight2k2]

Ironically I just got it worked out yesterday. I bought a KK and had the same problem. So that narrowed it down to motors and esc's. It was that the esc's didnt have multirotor compatiple code in them. I have the Turnigy AE-30. I bought the programmer for the SciLabs chipset and put the BLHeli code on them and it flies great now. It comes down to multirotor esc's needing to react very quickly to changes as opposed to doing some sort of averaging like the stock firmware did.

I hope this helps.

 

[mattjb]

Thanks for that. I have the Turnigy 25A Plush ESCs flashed with BLHeli. I think I will reflash them with the latest hex firmware and see if that makes any difference. Maybe some of my BLHeli settings got messed up in the first round of updating.