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Archive for January, 2009 - Page 2
Posted by Jack Crossfire | Jan 11, 2009 @ 03:22 AM | 3,670 Views
Quad cam 2 (3 min 59 sec)


Have some daylight video from the onboard cam. Hand launched automatic takeoffs, automated hovers, automated landing, manual abort, dead battery. The mane problem is loss of balance as the campaign wears on. Since she's upside down a lot for camera setup, the motors get misaligned constantly.

The humans seem to be getting more stable shots than the computers. The main weapon against instability is reducing position feedback. Position feedback currently tries to get the tightest position possible.
Posted by Jack Crossfire | Jan 09, 2009 @ 02:43 AM | 3,499 Views
Since any camera mount is going to require hand launches & landings, we did the hand launch & landing tests. Take a look.

hand launched VicaCopter (1 min 47 sec)


Got 1 hand landing before giving up on the idea. Hopefully your government won't command a hand landing program or your universal healthcare program is going to require a bailout.

Did 1 manual hand takeoff to show it was a bad idea. Hurls sideways for a long time before U get it under control.

Automated takeoffs R going to work for the camera mount. Ground landings R going to work for the camera mount because it won't flip over like a single rotor. To save battery power, U still have ground based manual takeoffs. Down to fabricating a stronger camera mount & lighter power supply. Also need a redundant battery for GPS.
Posted by Jack Crossfire | Jan 08, 2009 @ 09:58 PM | 3,420 Views
Should read the $parkfun blog more closely.

Gyros took another step down with the LISY300AL. Now only $12 per axis for the part & $30 per axis for the $parkfun board. That's cheaper than hacking PG-03's. U can build an IMU for under $50 in semiconductors or $110 in $parkfun boards. Expect thermopiles to die off shortly, & gyro stabilized toys to start appearing in malls.

Who knows how well the $12 gyros would do, but we suspect if U managed the voltages properly the cheap stuff could do just as well as the ADXRS150's. They could be the enabler for attitude that uBlox 5 was for position.

The trick with gyros is to get the quiescent voltage right in the middle of the A/D range & to keep the supply voltages exactly constant. A/D converters R nonlinear, so plugging 3.3V gyros directly into 5V microprocessors doesn't work. Not all voltage regulators R stable either.

Unfortunately we have no future IMU plans. UAV swarms, aerial refuelling, air launched daughter vehicles, they're all intriguing ways to waste time but they're not in the budget.

How about a VTOL which is dropped by a fixed wing to perform a mission & then snatched again by a skyhook mechanism on the fixed wing. Hopefully some rich Koreans R up to the task.

VicaCopters can be produced for under $600 in parts although we have no plans to move on it. The largest single cost is the uBlox GPS module.

To commercialize VicaCopter, U would need to do some things.

A Windows...Continue Reading
Posted by Jack Crossfire | Jan 08, 2009 @ 02:07 PM | 3,355 Views
90 minutes & $10 is what each crash is costing. You're in luck because GPS was in a good mood.

The fog was slightly clearer at 7:50, giving a huge GPS improvement. This detereorated hugely by 8:25 as fog increased & the satellite over Texas disappeared behind the hill. The satellites R in the same place every day, so U can mostly observe the effects of weather.

The slight algorithm changes & the 5Hz upgrade seem to be a success. When the air is still, the aircraft movement is a direct observation of GPS drift.
Posted by Jack Crossfire | Jan 07, 2009 @ 03:52 AM | 3,201 Views
So U think U can avoid the fog by flying earlier eh. Well, the only time it isn't foggy between commutes is when there aren't any good satellites.

During la ninas, Rain Ramon is socked in with fog instead of constant rain from Dec to Mar. In the 1990 la nina, the fog caused huge traffic pileups, killing almost as many people as the 1989 earthquake. La ninas cause very stable, cold airmasses to last for months in the Calif* valleys.

Today's crash was another bug in the landing software which caused her to shoot up 147ft without enough battery power to descend safely.

Today's flight times with no foam baffles:

Good 4Ah: 9m30s
Bad 4Ah: 6m57s
Posted by Jack Crossfire | Jan 06, 2009 @ 02:19 AM | 3,178 Views
So all of last week's styrofoam miracles R busted. The propeller baffles may have increased flight time slightly, but were too noisy. We need stealth in the communist sardine can.

Had fog, drizzle, & no GPS again. Can now guarantee you better keep around some human pilots if U intend to fly low & slow in fog.

One other thing. Our 57600 upstream Comca$t bandwidth may be related to Comca$t'$ new bandwidth throttling software. Those Romanian attackers R using it to turn everyone's $800/year plan into an $800/year brick by flooding everyone's IP address with garbage. Comca$t detects the attack as a bandwidth hog & shuts U down.

Finally, Hale Wayne or Wayne Hale or whatever his name is had a good story about NASA's management training classes this time.

Hale

In the private sector, company training is history, especially company training on mountain meadows in front of lodges. From the gourmet cafeterias to the dance classes, your government sounds like some kind of parallel universe from the 50's. Sheesh, heaven forbid your civil servants have to contribute to a health plan.

The irony is if any taxpayer found out their 70% a year was funding modern dance moves in the mountain meadows, Americans would probably vote to have their taxes raised even more to buy a proper dance floor.
Posted by Jack Crossfire | Jan 05, 2009 @ 05:10 AM | 3,447 Views
The first cam flight was impressive in terms of output, not in terms of flying. During manual takeoff, the takeoff position snapped to horizontal because of ground effect. Once airborn, the autopilot entered spirals until we commanded a turn. There was no vibration in the video. The only blurring was motion. Battery exhaustion occured just 5m35 seconds later.

Automatic takeoff didn't work. The computer couldn't handle the rapid snap to horizontal caused by ground effect. That was the end of the camera mount. The only economical solution seems to be hand launching & hand capturing.

Until your government commands a battery stimulus package, it's going to be mostly pencams. Would U believe they're still selling that crummy Aiptek from last year for the same price?

Quad cam without brightness

quad cam 1 (1 min 3 sec)


Quad cam with brightness

quad cam 1 (1 min 4 sec)
...Continue Reading
Posted by Jack Crossfire | Jan 04, 2009 @ 08:42 PM | 3,024 Views
So put on baffles to try to deflect rotor wash away from the fuselage.

Good 4Ah: 9m16s
Bad 4Ah: 8m0s
3.3Ah: 5m16s

But it was windy & we also changed PID constants. There's a chance with the baffles of having a styrofoam get sucked into a propeller.

The biggest problem is we never did full discharges with the 750mm motor spacing. They were just 1/2 battery flights.

For this week's video, we have timelapse hovers using different collective I constants. Thought I=0.0001 was the best. This video also has a vortex ring state which the computer recovered from.

collective tests (1 min 33 sec)


We have 2 ideas for vortex ring states. Stick with the current collective jamming or program some kind of routine which always ascends & descends briefly.

Comca$t lowered upload speeds to 57600 so it's now 1/2 as fast as the cell phone, so U can actually upload video faster on a cell phone than Comca$t....Continue Reading
Posted by Jack Crossfire | Jan 04, 2009 @ 04:03 AM | 3,149 Views
The theory with this is U can land & take off without being level. The main problem is it's going to give real short flight times. Also don't have a way to stick the styrofoam pieces together or attach it all to the fuselage. May be limited to pencams with the quad rotor.

Moved the motors closer in preparation for the camera mount. Got some current flight times with the closer positioning.

Damaged 4Ah: 5m51s
Good 4Ah: 8m51s
3.3Ah: 4m27s

Reason to believe the fuselage is interfering with the propulsion.

Also have finally converted the A/D values to battery voltages.

15800 = 11.9V
12600 = 11.2V
-1770 = 7.9V
-3830 = 7.5V

We've been quitting at 10.1V....Continue Reading
Posted by Jack Crossfire | Jan 03, 2009 @ 02:49 AM | 3,055 Views
The answer is yes. The uBlox 5 can do 5 Hz. Maybe that's why it's called the uBlox 5. When not locked in, U can force it to update at any rate U want, but it always clamps to 5 when it locks. So does a 5Hz uBlox fly any better than a 4Hz uBlox? Of course not! U think you're going to learn anything valuable from a free blog?

To the Blox's credit, it was windier during today's tests than any previous night test. We'll leave it on 5Hz because it feels good.

4 a good time, go to http://www.sfgate.com/webdb/jobcuts to find out whose head's about 2 B chopped off. You'd be surprised how much doesn't get covered by Time Warner & News Corp.

Some highlights:

E-Loan: 270
Symantec: 269
Boeing: 262
Ebay: 184
Vishay Semi: 97
National Semi: 151
Seagate: 91
Sandisk: 96
Thousands of healthcare layoffs
Thousands of insurance layoffs

But Time Warner said healthcare was an oasis. Fuggeddaboutit....Continue Reading
Posted by Jack Crossfire | Jan 01, 2009 @ 08:04 PM | 2,991 Views
If the Blox is bad in clouds, it's hopeless in drizzle. It couldn't acquire on the ground. Had to fly up manually to acquire, but even then the navigation wasn't there. The EM406 couldn't handle rain either, back in the day. WAAS status crashed on new years eve.

Had our first full batteries of manual flying. The quad rotor is indeed the most stable vehicle we've flown. Manual flying is more efficient than autopilot.

We seem to have done everything possible with the piano mockup. It's not as consistent as we hoped, but that could be mockup inconsistencies. Can't calibrate it without really playing it. The Dec & Jan paychecks went to paying for the HP & the Acer.

Still, our net worth decreased so much in 2008 that we would have been better off buying everything we wanted....Continue Reading