MultiWii / NAZE / SP Racing F3 The Nano Killer
- Thread starter Neverdone
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The latest versions of firmware for Multiwii are a huge improvement over just a year or so ago, that said if you've never used a Multiwii you're in for a steep learning curve. Tuning a Multiwii is a lot more hands on than many of the newer flight controllers from China but once you understand how it works and how to set it up for your own flying style they are a very capable controller for not a lot of $.
Best advice is to start with the basics, once you have it able to get off the ground and hover, no matter how twitchy that may be, then start working on the tuning. If you get the basic manual flight dialed in the rest is fairly easy, if the basic PID settings for pitch and roll aren't right nothing else is going to work right. Once you have that part set then start with one advanced function at a time, the autolevel comes next followed by altitude hold. When it can maintain altitude reliably and has a stable hover in autolevel mode then work on GPS which can be the most difficult to tune, especially if the other functions aren't fully dialed in. Make sure the compass is properly calibrated and I've found it best to tune the GPS in a large open area and have plenty of charged batteries on hand.
Ken
Thanks for the input!!!
I am new to the multirotor/multiwii world. I have quite a bit of flying experience/RC experience in general. Besides that I build and fab a lot of my own stuff. I have worked with an Arduino before but not in a flight controller so I have a little know how there. Besides that I work as an electrical engineer so I have some programing experience. I will be looking for some pointers and some base code to start with but after that I think I will be able to handle it.
Do you have any on board controls or LCD for debug or how do you make your adjustments? I do plan to start with all the basics then move up. Figure once I get all motors to run and in the right direction I will be doing good.
Other question is what radio are you running?? I have a DX6i now that I am going to get rid of and move up a step, but not sure if an 8 will work or go bigger?
I am new to the multirotor/multiwii world. I have quite a bit of flying experience/RC experience in general. Besides that I build and fab a lot of my own stuff. I have worked with an Arduino before but not in a flight controller so I have a little know how there. Besides that I work as an electrical engineer so I have some programing experience. I will be looking for some pointers and some base code to start with but after that I think I will be able to handle it.
Do you have any on board controls or LCD for debug or how do you make your adjustments? I do plan to start with all the basics then move up. Figure once I get all motors to run and in the right direction I will be doing good.
Other question is what radio are you running?? I have a DX6i now that I am going to get rid of and move up a step, but not sure if an 8 will work or go bigger?
The base firmware default settings usually work well enough to get the craft in the air and actually fly it around a bit, might be a bit wobbly but it should fly unless you have an unusual frame layout which can take some time consuming tuning sessions before they fly right.
You can attach a Bluetooth module and tune the basic parameters via Android smartphone. I've used it in the past and it's a tremendous help to be able to land, tweak a setting and then take off and see how it flys. Haven't used it in quite a while so I have no idea of the current state of the app and what it supports these days. I've had enough experience with Multiwii now that I can get the basic setup pretty close during the build, the rest is a matter of a few flights at the field with a laptop to make changes between flights.
FRSky Taranis, JR 11X, Futaba 10C, Spektrum DX7, I've used all of them at one time or another with Multiwii Pro boards. If you want to take full advantage of the advanced functions you'll need to have at least 2 - 3 way switches that can be assigned to Aux 1 and 2, and if possible also at least a 2 way switch for Aux 3. With all 3 switches you can setup just about any combination of functions you could need to use. At the very minimum you want at least one 3 way switch to allow manual, autolevel/altitude hold, and GPS modes, so that should be a big consideration when deciding on a radio. The Taranis is probably the best in terms of the number of switches and configurability but they're near impossible to get your hands on one without signing on to a wait list and waiting 3 months for the next production run, I waited nearly 4 months to get the one I have. Last year I was using the Futaba radio for most of my FPV since it could use the FRSky module, now that I have the Taranis I'll be moving all the models off the Futaba to it so I have the full telemetry available with voice alerts, hard to read a TX display screen with FPV goggles on
Ken
SoCal Blur
Member
Ken, maybe you can list some of the methods you use to determine what needs to be changed in the basic Multiwii setup during the build. I got my Multiwii from ReadyToFlyQuads and it was pre-loaded with the approprite firmware for my Octo so there wasn't a lot to change but I know that if you obtain it from other suppliers that it could be close to a blank slate. The info may be helpful to those considering the Multiwii but may be a bit gun shy because it isn't a plug-n-play FC.
I have to say the first thing I noticed on my FrSky Taranis was the number of switches and pots that are available. Fortunately I only had to wait 2 weeks for it to be back in stock at a US based company. 1 hour after I ordered it, it was again out of stock. It definately is a hot item.
I ordered my Taranis right after the first batch hit the USA and wait times were measured in months, now I hear it's down to a couple weeks usually but you do have to grab one as soon as they hit stock or wait again.
I don't recall where I found this or who the author was, but it has proved to be a very good guide to tuning not just the Multiwii but any controller that uses a PID based firmware. If you look at the section General Guidelines, that is pretty much how I tune mine. I use the M/W on small quads almost exclusively so I start with the default settings and go from there, they seem to be pretty close for a standard 350 to 550mm quad. Only ones I use very different settings on are my aerobatic quads that only ever get flown in manual mode, ever try a flip with autolevel accidently engaged? ...
I disabled it after the rebuild... Here's the tuning guide, author unknown...
*****************************
PID tuning theory and configuration guide for MultiWii
Now updated for multiwii >1.9
P is the dominant part of PID and gets you in the ballpark for good flight characteristics.
Basic PID Tuning - on the ground
Set PID to the designers default recommended settings
Hold the MulitiRotor securely and safely in the air
Increase throttle to the hover point where it starts to feel light
Try to lean the MultiRotor down onto each motor axis
You should feel a reaction against your pressure for each axis.
Change P until it is difficult to move against the reaction. Without stabilisation you will feel it allow you to move over a period of time. That is OK
Now try rocking the MultiRotor. Increase P until it starts to oscillate and then reduce a touch.
Rrepeat for Yaw Axis.
Your settings should now be suitable for flight tuning.
Advanced Tuning - understanding impact of P, I and D
P - proportional
P provides a proportional amount of corrective force based upon the angle of error from desired position. The larger the deviation, the larger the corrective force.
A higher P value will create a stronger force to return to desired position.
If the P value is too high, on the return to initial position, it will overshoot and then opposite force is needed to compensate. This creates an oscillating effect until stability is eventually reached or in severe cases, the overshoot becomes amplified and the multirotor becomes completely destabilised.
Increasing value for P:
It will become more solid/stable until P is too high where it starts to oscillate and loose control
You will notice a very strong resistive force to any attempts to move the MultiRotor
Decreasing value for P:
It will start to drift in control until P is too low when it becomes very unstable.
Will be less resistive to any attempts to change orientation
Aerobatic flight: Requires a slightly higher P
Gentle smooth flight: requires a slightly lower lower P
Integral
I provides a variable amount of corrective force based upon the angle of error from desired position. The larger the deviation and / or the longer the deviation exists, the larger the corrective force. It is limited to prevent becoming excessively high.
A higher I will increase the heading hold capability
Increasing value for I:
Increase the ability to hold overall position, reduce drift due to unbalanced frames etc
Decreasing value for I:
Will improve reaction to changes, but increase drift and reduce ability to hold position
Aerobatic flight:
Gentle smooth flight:
AP: Requires a slightly lower I to minimise wobbles / jitter
D - this moderates the speed at which the MultiRotor is returned to its original position.
A lower D will mean the MultiRotor will snap back to its initial position very quickly
Increasing value for D:
Dampens changes. Slower to react to fast changes
Decreasing value for D:
Less dampening to changes. Reacts faster to changes
Aerobatic flight: Lower D
Gentle smooth flight: Increase D
Advanced Tuning - practical implementation
For Aerobatic flying:
Increase value for P until oscillations start, then back of slightly
Change value for I until until wobble is unacceptable, then decrease slightly
Decrease value for D until recovery from dramatic control changes results in unacceptable recovery oscillations, then increase D slightly
Repeat above steps
For stable flying (RC):
Increase value for P until oscillations start, then back of quite a bit
Decrease value for I until it feels too loose /unstable then increase slightly
Increase value for D
General guidelines:
For stable flying with less wobble / jitter ( AP / FPV):
Lower P if you have fast wobbles
Lower I if you have slow wobbles
Higher D to smooth changes
For acro flying:
Lower D to make sharper snappier movements
You will have to accept a compromise of optimal settings for stable hover and your typical mode of flying. Obviously factor it towards your most common style.
Other factors affecting PID
Taking known good PID values from an identical configuration will get you close, but bear in mind no two MultiRotors will have the same flying characteristics and the following items will have an impact on actual PID values:
Frame weight /size / material / stiffness
Motors - power / torque /momentum
Position - Motor-->motor distance
ESC / TX - power curves
Prop - diameter / pitch / material
BALANCING
Pilot skills
Ken thanks for all your help and advice!! My FC came from HK, so I have not even hooked it up yet to see what firmware is on it. I will more than likely be ordering the bluetooth module for tuning purposes until I get the hang of it.
SoCal has good point, could you post up how you know what to change in the setup?
I looked at the Taranis radio and yeah that does look to be a pretty good bang for the buck. I just don't want to spend the loot and not end up with something that I want or not have enough channels. All my stuff now currently runs with spektrum so I really need to stay with something that can run spektrum equipment. Looks like the Taranis can do that. I think I will keep an eye out for one of them.
SoCal has good point, could you post up how you know what to change in the setup?
I looked at the Taranis radio and yeah that does look to be a pretty good bang for the buck. I just don't want to spend the loot and not end up with something that I want or not have enough channels. All my stuff now currently runs with spektrum so I really need to stay with something that can run spektrum equipment. Looks like the Taranis can do that. I think I will keep an eye out for one of them.
Well this has long been abandoned. But I just dropped some cash on it. Picking up a DX9 Black as soon as they are released, have one ordered through the shop with my name on it. Also picked up a Fat Shark FPV set. Also ordered through the shop. Can't wait for the stuff to show up! In the spring time this baby will be in the sky!
Struggling, but getting somewhere. Have the GUI working, but can not get the dumb thing to arm. Recieving good info from radio, but it will not arm. Adjusted radio endpoints, played with min and max throttle values, tried the ESC calibrate, nothing seems to work. Plug in batteries and a few seconds later the blue and green LEDs come on and start flashing as well as a Red LED flashes. Can anyone tell me what this means?
Any help would be great.
Also for the OBD put in a PIN header for the serial 1 port, and tried using that by defining for serial 1, but that doesn't seem to work either. Can anyone help with that?
I am uploading a copy of my config file as a TXT document. If anyone would care to look for something wrong.
Any help would be great.
Also for the OBD put in a PIN header for the serial 1 port, and tried using that by defining for serial 1, but that doesn't seem to work either. Can anyone help with that?
I am uploading a copy of my config file as a TXT document. If anyone would care to look for something wrong.
STUPID STUPID STUPID
Yaw direction was reversed in the radio. Corrected that and the pitch direction was off also. Now it will arm and spin up. Now need to mount some stuff down and try a test flight. Then work on getting GPS and OBD working. After that start setting up the FPV gear and other stuff......
Video of the first spin up......
http://vid248.photobucket.com/album... Killer/Hex Getting Dangerous_zpsqpwtdvun.mp4
Yaw direction was reversed in the radio. Corrected that and the pitch direction was off also. Now it will arm and spin up. Now need to mount some stuff down and try a test flight. Then work on getting GPS and OBD working. After that start setting up the FPV gear and other stuff......
Video of the first spin up......
http://vid248.photobucket.com/album... Killer/Hex Getting Dangerous_zpsqpwtdvun.mp4
I was finally able to get this thing off the ground recently. After many efforts with the Multiwii I bailed out off of that. Switched to a quick simple CC3d to give it a shot. First flash it took right off. I switched to 12x5.5 props due to lack of power. It would fly on the 10s but nothing like I had hoped. With the 12s it works great. But I have been having issues now with breaking motor mounts. Not sure why or what is happening to cause it. I started fabricating my own out of 1/8x2" aluminum. Should have those done soon and be ready to try again.
I did balance them all initially in my truspin. The last few flights I have had were very short lived. It almost sounds like the props are hitting something, but there is no evidence of it. One prop specifically seems to be having the most trouble. It does show signs of contact with something, also the last one that broke the motor mount. Since the mount is broke significantly I assume it actually did hit but after it came back down. None the less I should have the new mounts done soon, then will exchange that prop for a spare and try again.
Got the new motor mounts done. Test installed one. I need to get some longer bolts to proceed with this mission. New mounts may not be as pretty, but seem much more functional. Weigh a little more but not to noticeable to the calibrated hand. Not like weight is going to be an issue for this thing anyway.