MultiWii as CP Helicopter FBL (or just stabilization)?

Re: MultiWii as CP Helicopter FBL (or just stabilization)?

Postby dialfonzo » Fri Jan 20, 2012 12:41 pm

Thanks, but i don't want to use it wit FBL right now.
Just normal flybar to have "AutoLevel" feature.. ;)
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Re: MultiWii as CP Helicopter FBL (or just stabilization)?

Postby PatrikE » Sun Jan 29, 2012 3:15 pm

The code is now updated to latest version. r486.

More info in the aeroplane thread.
http://www.multiwii.com/forum/viewtopic.php?f=8&t=364&p=8312#p8312

/Patrik
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Re: MultiWii as CP Helicopter FBL (or just stabilization)?

Postby dialfonzo » Sun Jan 29, 2012 3:18 pm

Thanks..!
Need to re-assemble my 500 before trying
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Re: MultiWii as CP Helicopter FBL (or just stabilization)?

Postby leadfeather » Wed Feb 15, 2012 11:57 pm

Hi Guys,

I've been working on using the MultiWii code and a Criuss flight control board on a 450 helicopter. I'm using a brushless tail motor on this project. I've got everything working. The only issue I have left is that there is too much vibration from the chopper and the swash servos jitter way too much. I need to smooth the signal from the gyro's and acc's. I think the best way to smooth the signal would be to incorporate a moving average of the signal...that should eliminate the spikes from vibration.

Does anyone have the code writing skills to do this?

Here is the thread on rcgroups for my WiiChopper http://www.rcgroups.com/forums/showthread.php?t=1592666
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Re: MultiWii as CP Helicopter FBL (or just stabilization)?

Postby Hamburger » Thu Feb 16, 2012 1:07 am

Which sensor do you use? Some allow explicit filtering internally.
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Re: MultiWii as CP Helicopter FBL (or just stabilization)?

Postby leadfeather » Thu Feb 16, 2012 1:11 am

Hamburger wrote:Which sensor do you use? Some allow explicit filtering internally.


Here is the thread for the Crius flight board http://www.rcgroups.com/forums/showthread.php?t=1551599

Here is a list of the on-board guts:

·Dimensions 50 mm X 50 mm
·Standard Mk style mounting holes 45mm X 45mm
·Weigh 13.9g
·SMD component design with atmega328P
·ITG3205 TRIPLE AXIS GYRO
BMA180 ACCELEROMETER
BMP085 BAROMETER
HMC5883L MAGNETOMETER
·Design with servo output for Camera Pitch and Roll
·Separate 3.3v regulated supply for the sensors
·On board logic level converter

Lite Version (Gyro + Acc only)
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Re: MultiWii as CP Helicopter FBL (or just stabilization)?

Postby Hamburger » Thu Feb 16, 2012 10:15 am

then you may start using this (from config.h) and check how far it gets you
Code: Select all
/* ITG3200 & ITG3205 Low pass filter setting. In case you cannot eliminate all vibrations to the Gyro, you can try
   to decrease the LPF frequency, only one step per try. As soon as twitching gone, stick with that setting.
   It will not help on feedback wobbles, so change only when copter is randomly twiching and all dampening and
   balancing options ran out. Uncomment only one option!
   IMPORTANT! Change low pass filter setting changes PID behaviour, so retune your PID's after changing LPF.*/
//#define ITG3200_LPF_256HZ     // This is the default setting, no need to uncomment, just for reference
//#define ITG3200_LPF_188HZ
//#define ITG3200_LPF_98HZ
//#define ITG3200_LPF_42HZ
//#define ITG3200_LPF_20HZ
//#define ITG3200_LPF_10HZ      // Use this only in extreme cases, rather change motors and/or props
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Re: MultiWii as CP Helicopter FBL (or just stabilization)?

Postby leadfeather » Fri Feb 17, 2012 5:43 am

Thanks!

I was shown a section under the imu tab that smooths the yaw gyro. I mimicked this code for roll and pitch and increased the value of the smoothing constants and this seemed to work pretty good. This video demonstrates the difference with and without signal conditioning.

http://www.youtube.com/watch?v=MAQVesubv-Y
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Re: MultiWii as CP Helicopter FBL (or just stabilization)?

Postby Reflex » Fri Feb 17, 2012 2:30 pm

Sub'd
watching with interest
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Re: MultiWii as CP Helicopter FBL (or just stabilization)?

Postby PatrikE » Fri Feb 17, 2012 3:17 pm

leadfeather wrote: I was shown a section under the imu tab that smooths the yaw gyro. I mimicked this code for roll and pitch and increased the value of the smoothing constants and this seemed to work pretty good.


Is it this part?
Code: Select all
  #if defined(TRI)
    gyroData[YAW] = (gyroYawSmooth*2+gyroData[YAW]+1)/3;
    gyroYawSmooth = gyroData[YAW];
  #endif

In that case it could look like this for three axis.
Code: Select all
   #if defined(HELICOPTER)   
static uint8_t Smoothing[3]  = {3,3,2}; // How much to smoothen with per axis
static int16_t gyroSmooth[3] = {0,0,0};
   
for (axis = 0; axis < 3; axis++) {
    gyroData[axis] = (gyroSmooth[axis]*(Smoothing[axis]-1)+gyroData[axis]+1)/Smoothing[axis];
    gyroSmooth[axis] = gyroData[axis];
   }
  #endif


Can you verify that i can include it in the code?

/Patrik
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