How to Adjust Rates on a Quadcopter?

[Mastrmindz]

Hello interwebiverse!

I have tried to get into multirotors for about nine months now. I started off with a tricopter that was a blast. However, I started having a couple of FC problems and ended up with a Flip 1.5. I had trouble with the tri-configuration, so I converted it into a quad. It looks really slick. Here is a pic:



I have only done some initial hover tests, but I am having trouble adjusting it. The quad reacts strong and twitchy on the controls, and I find myself over-correcting the quad. When adjusting for smooth, lighter controls with the Flip 1.5, can you adjust the controls on the transmitter (Spektrum dx6i in my case); or do you have to adjust the rates in the WinGui on the computer? Thanks for the help!

Mastrmindz -(not so much)

 

[x0054]

You need to tune your PID settings. This should give you a good idea on what they are and how to adjust them:

http://blog.oscarliang.net/quadcopter-pid-explained-tuning/

Small PID changes make a BIG difference, so take your time and get it set right. You quad looks like a square, so your roll and pitch should be very close to identical. Yaw you may have to work on. You have to change the setting in the GUI for the FC. You can buy a bluetooth serial module to make PID changes wirelessly, it really does make it a lot easier.

 

[jhitesma]

PID's probably do need fine tuning, but it's not a bad idea to check the rates either.

You can use rates in your TX, but most people use rates in the FC since it gives more resolution and finer control. On MW you'll want to look for the "RC Rate" and "PID Rate" settings. In the MW Configurator program The column for "RATE" to the right of the PID settings is the "PID Rate" while the "Rate" box next to the throttle graph is the "RC Rate".

RC Rate is an overall rate - 0.6 is a good soft starting point, 0.9 is a nice starting point for more experienced pilots, above 1 and you can start to do some flips and such, above 2 if you're a pro PID rate on the other hand only comes into play when you move the sticks far from center. So by raising the PID rate but keeping the RC Rate low you can have a copter that's relatively docile around center stick but still capable of flips when you use a lot of stick.

Though some of this is a little different between MW 2.2 and 2.3 and I believe RTFQ is still shipping 2.2 on their boards and that should get you in the right range.

 

[Cyberdactyl]

And after you have your rates in a comfortable region, you can smooth out your flying a bit more by adding in some expo.

 

[Mastrmindz]

You need to tune your PID settings. This should give you a good idea on what they are and how to adjust them:

http://blog.oscarliang.net/quadcopter-pid-explained-tuning/

Small PID changes make a BIG difference, so take your time and get it set right. You quad looks like a square, so your roll and pitch should be very close to identical. Yaw you may have to work on. You have to change the setting in the GUI for the FC. You can buy a bluetooth serial module to make PID changes wirelessly, it really does make it a lot easier.

Thanks for your help you guys.

Yea. I saw that bluetooth module. Looked really useful. With the android app, tho, I only saw it available for version 2.1. I believe my flip is running 2.3. Do you think that would be a problem? And where would be the best place to order one? I am not confident in RTF-Quads' customer service at the moment and would like to get one the quickest way I could.

 

[Mastrmindz]

PID's probably do need fine tuning, but it's not a bad idea to check the rates either.

You can use rates in your TX, but most people use rates in the FC since it gives more resolution and finer control. On MW you'll want to look for the "RC Rate" and "PID Rate" settings. In the MW Configurator program The column for "RATE" to the right of the PID settings is the "PID Rate" while the "Rate" box next to the throttle graph is the "RC Rate".

RC Rate is an overall rate - 0.6 is a good soft starting point, 0.9 is a nice starting point for more experienced pilots, above 1 and you can start to do some flips and such, above 2 if you're a pro PID rate on the other hand only comes into play when you move the sticks far from center. So by raising the PID rate but keeping the RC Rate low you can have a copter that's relatively docile around center stick but still capable of flips when you use a lot of stick.

Though some of this is a little different between MW 2.2 and 2.3 and I believe RTFQ is still shipping 2.2 on their boards and that should get you in the right range.

Thanks Jhitsema.

I was not familiar with the differences between PID and RC rates, nor the exact changes that PID rates and RC rates had on the sticks. Now are the PID rates just the P, I and D values and the RC rates are labeled as "rates", or are you talking about the rates on the Tx? Thanks.

 

[jhitesma]

Yea. I saw that bluetooth module. Looked really useful. With the android app, tho, I only saw it available for version 2.1. I believe my flip is running 2.3. Do you think that would be a problem? And where would be the best place to order one? I am not confident in RTF-Quads' customer service at the moment and would like to get one the quickest way I could.

Bluetooth makes tuning so nice and easy. They just work like "a cordless USB port" basically as long as you're running the right version of software on your phone to talk to the version on your FC you're set. And the android version covers both 2.2 and 2.3 so you're covered whether you're on the RTFQ code or if you upgrade to 2.3. You can get the BT modules on ebay and amazon.

Any of these would work - but they default to 9600 baud so you'd either have to change your MW setup to set the serial port that slow or you'll have to hook the module up with an FTDI adapter and change it to 115k.
http://www.amazon.com/Innogear-Wire...d=1410931390&sr=8-3&keywords=bluetooth+module

http://www.amazon.com/Baitaihem-Ard...d=1410931390&sr=8-2&keywords=bluetooth+module

http://www.amazon.com/KEDSUM®-Ardui...d=1410931390&sr=8-1&keywords=bluetooth+module

Or ebay - under $9 from a seller I've used multiple times and gotten very fast shipping and just what I ordered. And it comes already set to 115k ready to go with multiwii:
http://www.ebay.com/itm/Flight-Cont...Control_Parts_Accessories&hash=item58b0e5913f

Thanks Jhitsema.
I was not familiar with the differences between PID and RC rates, nor the exact changes that PID rates and RC rates had on the sticks. Now are the PID rates just the P, I and D values and the RC rates are labeled as "rates", or are you talking about the rates on the Tx? Thanks.

PID values are different than "PID RATES"

PID values are the grid of individual P I D values for the various parameters. Those will likely need tuning to get your copter flying it's best. The article linked by x0054 covers it very well but there are quite a few discussions of it in just about any multirotor discussion forum

The "PID Rates" are the last column after D and are labled "RATE" not every parameter has PID rates even if they have PID values. The first box covers both ail and ele the second box should be Yaw.


PID Rates and RC Rate are both different than TX rates You can set rates in your TX as well, but due to how the calculations in a flight controller work it's more accurate to setup different profiles with different rates in the flight controller.

Can you get a screen shot of your setup in the MW config program?

 

[Mastrmindz]

Thanks for that info, jhitesma.

Here is a pic of my gui:



I have not touched anything on here yet.

With the bluetooth modules, how would I install it on the Flip 1.5? On Witespy's site, I only see how to connect it to the Mega board.

 

[jhitesma]

Ok, so you don't have any PID Rates which is good if you want it tame right now, if you want to start trying to do flips I'd turn the Yaw/Pitch RC Rate up to about 0.45 or so to start. The Yaw rate you may want to turn up to around .35-.55 if you want faster yaw response. I like mine even higher since I like to spin quick.

Your RC Rate is at 0.9 which is a decent compromise - but for getting starting you may want to drop that down to 0.6 or even as low as 0.4 if things still feel twitchy.

In general the rates/expo determine how it will react to your inputs. So if it's flying but too twitchy for you I'd work on those before I looked at changing the PID Values.

As for the BT module looking at the connection diagram for the Flip 1.5 it looks like the row of connections next to the USB port are what you want. They appear to be: DTR / TX / RX / 5V / NC / GND

So you'll want the RX wire from the BT to go to TX and the TX wire from the BT to to go RX. VCC/V+ from the BT module would go to the 5V pin and GND from the BT goes to GND. NC is "Not Connected" and DTR is generally only used when programming the main processor over serial which you'll never do since you have USB built in. So you don't need to worry about those connections.

 

[Mastrmindz]

Awesome! Thanks so much for all of that info. Have you thought of making a video of all of this information? It is really helpful stuff. And with the new popularity with witespy's product I'm sure a lot of ppl would like it. I probably never would have known that info by myself. Thank God for forums. Lol. Thanks again jhitesma for that info.

 

[jhitesma]

I just got my mobius recently and am still getting used to setting up shots without a viewfinder It's also hard for me to do videos since most of the time I have to spend on this stuff in in the evening after my daughter goes to sleep...and our house is so small I can't really be making noise after she goes down. Our back room where my computer is is pretty well insulated from the rest of the house...but the light in there is horrible and I need to get some rolls of white LED's to make some better lights from. Oh yeah, my computer that's powerful enough to edit video is also out in the living room where I can't use it after my daughter goes to sleep (her room's door is just 4' from the living room TV, it's a small house.) I keep meaning to pickup a new video card for the old computer in the back room so I can get HDMI out on it and swap it with the good computer...just keep spending the money on RC stuff instead, need to go a few weeks without breaking anything

I've also had a nasty infection followed quickly by my seasonal allergies so my throat is all torn up right now and I'm coughing which isn't very good for narration

But I do hope to make more useful videos in the near future, I'll keep a topic like this in mind for something to try making one on when my throat is feeling better.

 

[Mastrmindz]

Here is a vid on the quad without the rates changed:

 

[Mastrmindz]

But I do hope to make more useful videos in the near future, I'll keep a topic like this in mind for something to try making one on when my throat is feeling better.

Sounds good.