Posted by Aldo Vargas on January 21, 2010 at 9:30am
Hi everybody!!!I'm making a stabilization system for a helicopter, hehehe, another one...First of all i want to show my hardware:- ArtTech Falcon 3DRotor Diameter: 24.8"Tail Rotor Diameter: 5.98"Weight: 19.5 oz.Length: 26.4"Servos: 4 9g servosTransmitter: 6 channel 72MHzReceiver: 6 channel dual conversionBattery: 3S 1300mAhr 10C LiPoMotor: Brushless B20/10TESC: 18A Brushless
- The great Arduino as Avionics- IMU 6DOF Razor ( http://www.sparkfun.com/commerce/product_info.php?products_id=9431 )- Small arduino shield build by me, just with the purpose of holding and connecting the razor to the arduino.Software:- DCM modified by Automatik, 10x a lot man!!! ( i had made some modifications, for making the arduino control servos for pitch and roll)- LabView VI made by Automatik, 10x again man!! ( with a little bit of modifications )What have i done so far:- I've had a lot of problems with vibration!!!! its the thing that had stop everything!!!- We try several configurations, with foam, and other stuff.- The configuration that work the best, its a base with rubbers and velcro, a little hard to explain in english, so ill just paste a picture....
In this picture, the heli is showing the base, and you can see the rubbers.
You can see the shield and the arduino, mounted inside the landing gear.
You can see the usb port, its on the back of the heli.
I just uploaded a video, with the first test with the rubbers and velcro, sorry, its in spanish, because it was for my faculty advisor, hehehehehttp://diydrones.com/video/instrumentation-with-rubbersVibration Issues:In the next pics you can see the problems i had with the excesive vibration produced by the helicopter, and this issue make the stabilization impossible!!!! Because the angles are completly crazy!!!This test was conducted with the DCM filter and half throttle.
This test was conducted with the kalman filter and half throttle.
What do i want right now??In this moment i just want to focus on stabilization, and mainly in pitch and roll, i will not take care of yaw...Any help, comment will be greatly appreciated!!!10x a lot!!Saludos!!
If you power the Xbee unit completely seperately you may not experience too much EMI (besides radiating), or you could try and implement a band stop filter at that frequency on your sensors
Yes, thats a problem!!! i tought on using a xbee module, but the EMI generated by the xbee, its going to affect in a great way the IMU, so, my solution to that is to peal the usb cable, make it very thin and flexible...
I could avoid the communication between the pc and arduino, but i need to record the angles, for the neural network training, or, using a memory logger system, any idea??
I had a thought, that maybe having the arduino connected to the PC while operating the helicopter could be dampening your rubber bands considerably (if you're just letting the cable hang off), which could increase vibration picked up by the accelerometer.
I would spend some time on the mechanical setup of the helicopter. Balance the blades firstto have the same spanwise center of gravity, then add weight at the cg to balance the pair. Pull the main shaft and head and balance the head. Check that your tail blades are equal weight to within .1 gram. And then make sure the main blades are tracking perfectly. Every time you have any sort of a crash, however minor, pull all the shafts, inclding the spindle shaft, and make sure they are true.
If any of that does not make sense the mini and micro heli areas on rcgroups are a great resource.
Nice progress so far! I am working on the same thing, except with different sensors (and ultra-low budget lol).
Unfortunately I haven't got mine hooked up to helicopter yet, I know I'm going to need to grapple with vibration issues. Your setup looks really nice and neat, I think I'll give it a try!
very cool, care to post your implementation? looks cool.
I can see the accelerometer having that much noise but the gyro should be pretty clean. What's the performance specs of your gyro?
Comments
I could avoid the communication between the pc and arduino, but i need to record the angles, for the neural network training, or, using a memory logger system, any idea??
10x for all the comments!!
If any of that does not make sense the mini and micro heli areas on rcgroups are a great resource.
Unfortunately I haven't got mine hooked up to helicopter yet, I know I'm going to need to grapple with vibration issues. Your setup looks really nice and neat, I think I'll give it a try!
The gyros are the LPR530al ±300°/s range
Datasheet: http://www.sparkfun.com/datasheets/Sensors/IMU/lpr530al.pdf
What part of the implementation would you like??
I can see the accelerometer having that much noise but the gyro should be pretty clean. What's the performance specs of your gyro?