MultiWii / NAZE / SP Racing F3 Bad MultiWii Pro? Advice appreciated

[HighFlight2k2]

I have been struggling with this since I got it. I worked through noobie issues but now I can't help but feel I am past that and am possibly dealing with a bad board.

Basically, I can't get the thing to fly stable at all. It's always oscilating. To get it to fly without crashing, I have to turn the PIDs down so low (1.0, .01, 0 for example) it negates the benefits. Even then, it still has oscilations. I started with defaults then through reading tried the I and D at zero working on P until it oscilates. I don't get very high.
I have calibrated the ESC's on the copter (USB plugged in for power, arm, full throttle, connect battery, wait for music, low throttle, after music unplug all). I have calibrated ACC and MAG. They are smooth as silk when plugged in. I have tried 2.1, 2.2, and 2.3 clearing the board before each upload. The BAR is not steady even when sitting on the bench. I do have foam over it. This might be normal...not sure. Props balanced. CG perfect.

My goal was to get position hold. I want to do FPV with head track eventually. That's why I got the MultiWii Pro. I am wishing I threw a KK2.1 into the order at the same time so I could test with it.

Any ideas?

 

[RTRyder]

The Baro trace will fluctuate sitting perfectly still indoors, that part is normal. Unless something is badly mismatched, motors, props, battery, etc, it should at least get off the ground and hover controllably on the default settings with 2.2 and 2.3 firmware. May have some oscillations with the defaults but it shouldn't be so bad that you can't control it.

Before I could make any recommendations I'd need to know a lot more about the gear on the quad, where did you get the M/W board from, what are the motors, prop sizes, and what battery are you using? A screen shot of the M/W GUI with the quad powered up and sitting on the bench would be useful as well.

Ken

 

[HighFlight2k2]

Thanks for the assistance Ken. I'll try to answer all your questions.

The motors, ESCs and props are all matched from a model and age perspective. Is there more to matching? This is my second quad. My first was a Blade mQX. So that's the only point of reference I have. I can hover that no problem. Even in light wind. With the default settings (I will include a snap), I can get it to hover inside but can easily induce a "freek out" simply by a slight left then right on the roll. Outside it will freek out eventually just hovering once a bit of wind hits it. With the PIDs way down, it will hover even with some dramatic input. But obviously it's not self stabilizing.

All my parts are from Hobby King. I tried to pick good stuff in the hopes to avoid early spoilage.

MultiWiiPro http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=39478
Motors AX-2810Q-750KV http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=47692
ESCs Turnigy AE-30A http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=30699
Battery ZIPPY Flightmax 3000mAh 3S1P 40C
Props Slow Fly Electric Prop 11x4.7 http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=38927

I have now uploaded the default 2.3 code. The only changes I have made in config.h are #define QUADX, min and max throttle, and #define FFIMUv2.

Thanks again for any assistance.

Jon

 

[HighFlight2k2]

I also took a quick video of it. I tried to keep it close to the ground for obvious reasons. But notice at ~1:20+ the oscilations. If I tried to fly it around, it would almost immediately freek out. I can slow that down with the super low PIDs but again, at times, it is still unstable.

Thanks.

http://youtu.be/f-Rt_uV0qLk

 

[RTRyder]

It actually doesn't look that bad once it gets off the ground, the oscillations should be able to be tuned out if it's that stable at take off. One thing I do notice in the screen shot is that there are no traces showing activity from the Accelerometer, are you sure you have the correct board selected in config.h? Usually no accel activity means one of two things, the wrong configuration for it in the firmware or it's broken. I would strongly suspect the first to be the case, done it myself a couple times with some of the lesser knock-off copies from China.

If you do have the wrong config in the firmware that would explain pretty much everything you're seeing happen once it gets in the air. I'd start there and verify all the correct bits of code are being loaded, that may mean having to find the accel chip on the board so you can identify for certain what it is and then find what code is being loaded to make sure they match. If the wrong accel code is loaded there's a good chance the gyros aren't right either and that could explain the instability when you try to move out of a hover.

HK website says the board has the following...
• ITG3205 Triple Axis Gyro
• BMA180 Accelerometer
• BMP085 Barometer
• HMC5883L Magnetometer

I'd double check the board and the code, sometimes they make changes in the components but never update the website.

Ken

 

[HighFlight2k2]

I wasn't really sure what to put in the screen shot. The ACC's definitely are working. The pitch, roll and artificial horizon track perfectly if I pick it up and move it around. I wasn't sure how to get a video of that process. The documentation and forum entries I found said to enable FFIMUv2 rather than each component...but I will check the board and see if they match up directly. I will try anything at this point.

I did get an extra motor and ESC when I ordered everything. I am thinking about swapping the motor and ESCs one at a time to see if there is any difference. It does always seem to be the front right to back left diagonal that has issues. You can see that in the video.

The first time I took it off and it was a little shakey I was hopeful and throught to myself "cool, this will just take a little tweeking". But I haven't been able to tune it out. I am frustrated to say the least.

I am also going to be on the lookout for a KK. But ultimately I want something with position hold. What is the step up from the MultiWii Pro? Would that be the Naza?

Thanks.

Jon

 

[Electro 2]

This is the "red board" made by Holybro Hobby with the design flaw. Heavily detailed early on, in the other forum. A 5V regulator in series with a 5V external supply yields low voltage to following sensor regulator, Hence low voltage to sensor suite. It has to be modded to function correctly or used with an external voltage supply of above 6V, i.e. a 6V BEC. Could be the source of your issues. (I have one of these cards, too.)

 

[rwilabee]

Where can you find info on the mod that needs to be done.

Rich

This is the "red board" made by Holybro Hobby with the design flaw. Heavily detailed early on, in the other forum. A 5V regulator in series with a 5V external supply yields low voltage to following sensor regulator, Hence low voltage to sensor suite. It has to be modded to function correctly or used with an external voltage supply of above 6V, i.e. a 6V BEC. Could be the source of your issues. (I have one of these cards, too.)

 

[Electro 2]

Where can you find info on the mod that needs to be done.

It is to remove the 5V regulator and shunt around it. If this statement doesn't ring any bells or you're not comfortable with SMD solder work, the mod is not for you. The external 6V BEC route is the way to go. It was contained within the thread dedicated to this board on the other forum. Early in the thread, maybe a year ago. Don't remember the poster's avatar, sorry.

 

[brewski]

Go to RCGroups & run search on your board. I personally would return board for refund as HK know it has a manufacturing fault. Buy a genuine Crius AIOP V2 & you will have no issues provided you use it with external BEC with 5.5V output. You require this due to a diode on incoming 5V (if using ESC BEC) dropping approx. .5V & running AtMega2560 dangerously close to its minimum voltage.