First flight ...

Here is the fists flights of the quad copter:

Note: Very windy conditions and still so stable !!!

At the flight time test ... amazing more than 10 minutes (14 to be more precise) with 4Ah Lipo. This is good time for a quad copter. 

Simple PID adjustment

I was just hit by a idea:
Adjusting PID parameters can be a pain in the ass if the adjuster have no idea what is he doing.
Adjusting as we fly it:
Step 1: have a flyable backup parameters that you can switch with a flip of a finger so you wont crash. This backup can be determined by holding the drone in your hand and see the response but for perfect parameters we need a method to calibrate PID inflight.
Step 2:use one of the AUX channels to activate PID adjustment P parameter (I and D are calculated), than use a VR (futaba like) to adjust the parameter until comfortable fly. I and D parameter can be calculated by the board using Ziegler-Nichols method.
Step3: as soon you have comfortable fly behavior (no woble), land and save the parameters.

The I and D parameters can be determined later by trial and error or/and using http://en.wikipedia.org/wiki/Ziegler%E2%80%93Nichols_method , but the P is important and makes the thing fly. I think we can have the P manual determined by inflight calibration and the I and D calculated by the Ziegler-Nichols method.

Usual the Roll/Pitch PID parameters are the same values for a Quad/Hexa/Octo copters. So why not adjust manually inflight the P parameter same for Pitch and Roll and let the I and D be calculated with the method Ziegler-Nichols. Like this you can achieve the best PID parameters.

Many of the people around here use wifi/bluetooth serial transceivers to do this from GUI. I think it can be implemented (like in flight calibration) to be available from tx also.

It is just a idea, so please do not jump on me. My quad-copter is calibrated by hand with trial and error. Same is my tri-copter.

I got this idea from experimenting with my helicopter the gyro gain in rate and head-hold. I use a VR potentiometer from my futaba to adjust the sensibility of head hold gyro until no wobble than I land my helicopter and check the settings (the value of the channel) and set it as default parameter for that helicopter.

I think this will solve the PID adjustment problem that many have and is not so difficult to be implemented in multiwii software so I will give it a try to code it and keep you informed.

Mongoose Multiwii 1.9 Download SourceCode

As I promised here is the current source code:
 
http://www.4shared.com/rar/wFnVAFjM/Mongoose_Multiwii.html

I will give more details for calibrating if you can not find it on MultiWii forum.

You can see in the picture below what board you must select for MONGOOSE 16MHz version:

 

As soon I will have time the difference that need to updated for multiwii will be posted on multiwii forum and hopefully will be included in the main distribution of the multiwii so we can get the updates directly from multiwii.

I will work from this point (the source you can download already) to implement and experimentation of the fuzzy logic to replace current PID controller and I will keep updating this blog with the latest implementation.

With the good willing of the Ckdevices guys I will receive the second MONGOOSE board and with this one I will develop the helicopter auto stabilization system and a flybarless controller.

So actually 3 projects will be in development from this point forward:

1- Flying Drone

2- Helicopter autopilot / Flybarless system. 

3- A mini quadrocopter less than 200g

I can say this: MONGOOSE is perfect for mini quadrocopter. For this mini I will use 1 Cell LiPoLI and build a small version of the quadrocopter to have fun indoor (in the comfort of your home).

Connecting motors and Radio Receiver to MONGOOSE

I have finally connected all the motors and made everything work.
Here are some pictures:

The next picture is the motor orientation:

 

The connection should be like this:

Motor Front Left: Pin  3 (PB3)

Motor Front Right: Pin 10 (PB2)

Motor Rear Left: Pin 9 (PB1)

Motor Rear Right: Pin 5 (PD5)

Servo Camera Stab: PD6

The PPM sum from my receiver I had to connect it to PD2 (Atmega328 pin 32)

 

As you can see you have to manual solder the pin 32.

I have added the Atmega 168 pin map because is the same with 328P. You can see the PB3 (Motor Front Left) is connected to MOSI connector that is available on Mongoose.

With some tweaks and bells I have managed to change the multiwii 1.9 to work with mongoose ckdevices board.
Here is the configurations I have tried:

Before i will release the source code, I need to wait a better weather so i can properly fly and test the quadrocopter. I tried some flying indoor in my house but the space is very limited and I did not wanted to risk crashing before I fly it. I did a little hover in Acrobatic mode (gyro only) in my house and it looks promising.
Today was minus 23 C degrees outside and full of snow and until 4-5  February it seems will be same cold outside so no chance to fly it.
Feel free to ask any questions about the connection diagram.

The project goes on

As i promised here are some pictures about the work in progress. I Hope this will guide you how to do it if you will choose the materials i choose to build this Quadrocopter.

  

As you ca see in the picture above, i had to manual solder pin 32 because i will need to have a hardware interrupt to read the PPM SUM from the radio receiver. To do this, you will need a soldering iron and some soldering skills.

My advice is to attach a small development PCB board and build there the POWER PINS, RX Pins and so on. Try to solder as little as you can on the MONGOOSE PCB or you could damage it if you solder many times.

As you can see I have soldered the RX plug to the PCB I have attached near MONGOOSE that i will call from now on  POWER BOARD.

The signal PPM SUM must go to pin 32 of the AtMega 328, the +5V and the GND of the RX and MONGOOSE must be connected in parallel.

The red and black wire will come from one ESC with +5V to power the mongoose and RX receiver.

When you will power the electronics ( Mongoose and RX receiver) from a +5V power source, it is safe to plug in the FTDI USB to USART (Serial). When FTDI and external power are plunged in  the MONGOOSE and RX will be powered by the external power and FTDI will get his power from USB.

In the above last picture I have powered the Mongoose and RX from a NIMH batery that gives +5V trough red and black wire and also FTDI is plugged in and connected to USB so as i said before it is safe to power like this, no smoke will be produced.

 In the pictures above you can see I have mounted the ESC on the quadrocopter frame. The pictures explain more than I could explain with words.

Now that i have soldered the ESC to motors and to the signal cables, I have to solder them to MONGOOSE digital PINS and also solder the servo for camera stabilization to the power board. 

  

Mongoose 9DOF arrived

In the meanwhile the Mongoose finally arrived.
I have to say i am very impressed with the job they did building this little powerful device. Of course the first thing i did was to mount the pins on the serial header so i can connect it with the FTDI USB to USART. and see if all works.
I was somehow expected to see it working but not as good i saw it working. Very fast response, ZERO problems and the size, well the size is comparable to pro mini and i am afraid that if i will snooze i will break it. It does look fragile but it is very robust device and very well built

I decided first to use MultiWii as base code and make the modifications to work with Mongoose board and do not worry i will make it public with parameters and so on. Actually i will make modifications of the default values to work with my setup, so if any of you will buy the parts i was using you will get a flying multicopter out of the box.

As soon i will have a flying version of the software based on multiwii (PID based) and win my prize from ckdevices :P, i will start working on a fuzzy version of the stabilization control that will be build from scratch based on mongoose.

I will post some photos tonight of the work done as soon i get home from work.

Quadcopter Frame Build Info

I finally got the time to start working on the frame.
The first things I noticed was that arms were not well glued and easily and with patience i take them apart piece by piece. It can be done with much care so you do not brake it.
Will be great if the manufacturer will sell them unmounted and unpainted.

With a little sand paper, allot of work and epoxy glue (A+B) I've put them back together after i removed some of the paint from the surface they will be glued on.

At the beginning i felt the arms to soft to hold on for the stress of flying but now after I re glued them they got allot of strength and I am confident they will withstand to any maneuvers i will make with my quadrocopter.

I will have to paint them again and i think i will choose X Quadrocopter flying so 2 red and 2 light grey.

I've also re glued the camera mount part.
I think the rest of the pieces will mount together with the plastic screws contained in the package. So actually this quadrocopter can be mounted and dismounted as many time you like, but i wold not recommend it.

I will try mount them with screws and also add some glue in some parts i will never unmounted.

I have to say that the plastic screws and nuts are very bad quality and i had to replace the plastic nuts with metal.

Parts Lists

As i promised here is the part list I'll be using for this quadrocopter:

• HobbyKing Quadcopter Frame V1   

 

         Overall this airframe looks sexy with a very good price. 

Cons: 

1. Being so cheap comes with a  major problem and that is bad quality on used glue to mount the preambled arms. The solution is to carefully disassemble the arms parts and re-glue them.
2. Too little stock avaible.
3. No spare parts, but for 14.99 USD you could buy 2-3 kits and use them as spare parts.

Pros:

1. Building is Ply wood and this material is light weight but strong.
2. All the parts come with a nice finish and painted.
3. Nylon nuts, bolts and spacers have been included to keep the flying weight down.
4. This frame have a camera mount with vibration dumpers that will receive a servo for vertical movement of the camera.

    I will use sandpaper on all unpainted parts than spray protective coat on all the kit to give it a nice finish look.

• Mongoose 9DOF IMU 1.0

Cons.:  I can not say anything. I need to wait to receive it and evaluate it.

Pros: Small, smart, light weight, complete sensors.

• Motors (4 of them) hexTronik DT750 Brushless Outrunner 750kv

• Propeller Counter Rotating combo 1147 (1147*1 & R1147*1) (2 x 3pc Each)

• ESC - 4 pieces

1. Hobbyking SS Series 25-30A ESC (card programmable)
2. Hobbyking SS Series 18-20A ESC (card programmable)

• Battery

1. Turnigy 2200mAh 3S 30C LiPo Pack
2. Turnigy nano-tech 2200mah 3S 35~70C Lipo Pack 

As a battery you can use any 3S with minimum 25-30C discharge and at least 2200mAh but be care full spare space and possible weight are limited in a flying drone. I will do some tests with a 4000mAh 20C when the flying will be possible and get back withe the results.

Mongoose fuzzy quadrocopter project start

Project Start 06 Dec 2011

    This is the wonderful start of a flying drone quadro-copter  based on the Mongoose 9DOF from ckdevices:

    The new things this project will bring, will be using fuzzy logic control to fly and control a flying drone using gyros, accelerometers, digital compass (magnetometer) and level altitude (barometric sensor).
    All sensors mentioned, combined with Atmega328Pmicrocontroler running on 16Mhz exists on the Mongoose board and they can be used as they are without any modifications.


    The next post will be with the necessary materials you need to start the project !!!

HobbyKing QuadroCopter airframe