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CSU Chico Tilt Rotor Flying Machine, (Airframe and Electronics, 2 of 3).

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Patrick

Wed Jun 13 2012, 05:41PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

AndrewM wrote ...

This idea also reminded me - you might consider attaching a number of 4' long wooden sticks to your models primary axes. These will greatly increase your moments of inertia while adding fairly little mass. It will be much easier to fly and tune.

An example is these popular coaxial helicopters:
250

There is, in fact, nothing inside that fail boom; its just a thin plastic shell. However its not purely decorative; without that boom it is completely unflyable as the gyro and control loop cannot damp the oscillations.

thats a great idea, ill do that and report back!

EDIT: ill only put one rod on the roll axis, thats the only axis thats really problematic.

EDIT: It worked... Duh! now i see what steve and andrewM meant, when i lifted the CL above the CG i was creating a vertical pseudo-rod, which helped the pitch some what. As for roll, the rod worked perfectly, even the high freq oscillations in RPM are gone. it's like flying a wholly different machine now!!! Both my ace pilot Corey Koehler and I can fly it...he better than I, but with accerlometers i can definatly program a waypoint and computer pilot, and then generate a SLAM model in real time.

AI flight and IARC 2012 are now within my grasp.

Patrick

Thu Jun 14 2012, 03:33PM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Ok here are the modified pics of the airframe...

48" long wood rod with steel washers.

Torque tube and Power 10 motor.

Servo and Fan section.

All up machine.

Im still trying to figure out video, so give me awhile. I dont want to kill the sites storage...

Steve Conner

Thu Jun 14 2012, 09:33PM

Registered Member #30 Joined: Fri Feb 03 2006, 10:52AM
Location: Glasgow, Scotland
Posts: 6706

I think the easiest way to post video on here is: upload it to noobtube, make it unlisted so regular Youtube users can't view or comment on it, and allow embedding. Then use the YouTube button in the forum editor to add a link to it, and the video will appear right in the thread.

Patrick

Fri Jun 15 2012, 06:35AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Im still trying to figure out video clips so please excuse the breif lame clip below, ill also trying to get a YouToob channel up soon.

CSU Chico Flight Club, Tilt Rotor UAV for IARC 2012.

Description: "Tilt Rotor UAV Drone Test, CSU Chico Flight Club. Flight test conducted by Corey Koehler (A Main Hobbies.com) and Patrick Coleman (EE, CSU Chico), seen in the above clip is the dreaded roll oscillation. This problem has since been solved."

This clip shows the rapid oscillations in the roll axis (left and right tweaking out), then we land it, as of now the rod suggested by AndrewM, has solved this problem entirely.

EDIT: I think this is my YouTube channel, is it?

I dont know how to put text bubbles pointing to places in the video, which for tecnichal demonstrations is kind of important.

Patrick

Sat Jun 16 2012, 04:58AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

New pics of servo horns...

Old horn on top, new horn being made on bottom.

Broke a tap, consequently i have started drinking tonight...

Notice the recessed nut hole for the ball stud.

Ball socket turnbuckle, made from hardened titanium, 2.350 inches long.

Patrick

Tue Jun 26 2012, 01:50AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

oops! crashed it!!

it works well, CG, CR, CL have all been balanced and tuned to the point where it holds a hover, however its still difficult for me to fly. And i crashed it in, broke a titanium gear. Anyway i still need to generate a velocity PID controller to operate from data provided from the 9 DOF gyro-mag-accel MEMS IMU....

Patrick

Wed Jun 27 2012, 02:06AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

Ok having evaluated the recent crash and damage, i believe it is vulnerable to "pitch tip-stalling" . however i dont know what to do about it (other than reducing the angle once it approaches critical). Need input please.

tobias

Thu Jun 28 2012, 02:04AM

Registered Member #1956 Joined: Wed Feb 04 2009, 01:22PM
Location: Jersey City
Posts: 172

Does it needs to have this configuration? Why not to go for a proved/simple design?

Patrick

Thu Jun 28 2012, 02:53AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

tobias wrote ...

Does it needs to have this configuration? Why not to go for a proved/simple design?

this design was choosen for some of the advantages over the quad rotor, like better lift better flight time, and most importantly a can have better views of the compition arena for my sensors...but the liability is that its more difficult than a quad to stabilize.

Patrick

Sat Jun 30 2012, 12:34AM

Registered Member #2431 Joined: Tue Oct 13 2009, 09:47PM
Location: Chico, CA. USA
Posts: 5639

It works ! ! ! * (though I did crash it)

Pitch instability problem... solved!
Roll oscillations... solved!

It can lift more than 1.7Kg's! AUW (3.7 pounds)
landing gear will be changed to the 700 sized heli skids.

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