Can't get ArduCopter off the ground

My friends at DIY Drones:

Following the Arducopter online manual, I have finished building my first Arducopter, calibrated my ESCs, initialized it with the configurator, setup the RC, and ran successfully through the Pre-Flight test. As far as I know, I followed all the steps correctly.

In terms of parts and configuration, I have a pretty standard Arudcoputer:

Software:  Arducopter_alpha_1.0
ESCs: Turnigy Basic 18A 
Motors: KDA20-22L
Front/Back Props:  APC 10x4.7 Propellers, lettering facing up
Side Props: APC 10x4.7-P Pushers, lettering facing up
RC: Futaba T10CHG Tx (in airplane mode) & 8-channel Rx.
Frame Arms:  aluminum arms from beta kit
Frame center:  several thin sheets of perforated aluminum, same size as beta kit
Battery: zippy 2200 3 cell lipo
Total Weight:  967 grams

I just did my first flight test. I arm the motors. Then I push the throttle forward. The front and back props spin proportionally to how far I push the throttle forward. The left and right props don't spin if I push steadily forward, but if I tilt the joystick to the left or right, then they'll come on, but at the same time, the forward and back props go off (even though the throttle is well on). As I move the joystick around, the front/back spin hard or the left/right spin hard, but seldom do they spin together (though sometimes rarely they do). My first question: Is this normal behavior? I guess I assumed all the props would be spinning more-or-less all the time to a greater or lesser degree. I wasn't expecting two props to go off when the other two props go on.

As I do this, even when when I push the throttle all the way on, the arducopter does not lift off. It's not even attempting or struggling to almost lift off. It's working extremely hard at something, but taking off isn't it. As I move the throttle joystick around (or the right joystick also) I can see the motors responding and the unit rocks back and forth, and tries to turn, as it changes the engine speeds, but no lift off at all. 

My first thought was that I have the propellers on backwards or something, or the motors are spinning backwards, but I tried to be careful on those points when I assembled it (When I first built it, I did switch the direction of two motors by switching two of the ESC wires so that the motors were turning consistently with the diagram in the manual).

So, I'm not sure what the problem is. If any of this sounds familiar, or if you could help narrow my tests and diagnostics, I would appreciate it. It could be that you'll hear these symptoms and know from experience where I've gone wrong.

At this point, with out any further information, I'm going to start a general diagnostic process to see if I can isolate the problem: 

1. When I got to the motor calibration step in the manual, I tried to do that properly, but the beeps are a bit hard to interpret (I come from the robotics world rather than the RC world, so ESCs and this type of brushless motors are new to me).

2. I'll double check all my motor/prop directions to make sure the right ones are CW and CCW, etc. Maybe in my attempts to make sure I got these on right, I did it exactly backwards or something.

Any clues you can provide to help me in my diagnosis of the problem would be much appreciated.


Tags: arducopter, no, take-off

Views: 542

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Replies to This Discussion


ModeratorPermalink Reply by Sgt Ric on October 9, 2010 at 12:41pm
Since none of the 'copter people have replied yet, let me jump in here... I hope I am not wasting your time, but here goes.

A few years ago I made the change from nitro engined flight to electrics and found that often the electric props are not always as obvious as to the correct way to mount them so they are facing forward, especially a simitar type prop.

The first time I installed one facing what I thought was forward, the EZ flew pathetically and seemed unable to gain altitude.
There seemed to be a good amount of prop wash pushing it, but once I "reversed" the prop after some advice, it was amazing the difference.

Maybe this doesn't apply, but it's all I can suggest, especially if your motor/esc/battery combination has worked for others(?)

P.S> I see you have thought of this and made the changes, (even documenting the lable side of the props) so this is probably not going to help at all.

3D RoboticsPermalink Reply by Chris Anderson on October 9, 2010 at 12:52pm
It sounds like you've got your RC set up wrong. Did you configure your RC with the Configurator? Are you in airplane or helicopter mode with your RC?
Permalink Reply by Robert Beatty on October 9, 2010 at 1:18pm
Yes, I did configure the RC with the configurator. That seemed to go smoothly and it all made sense to me at the time. However, this is my first experience with RC, so it's quite possible I missed something there.

Regarding airplane vs. helicopter: I thought the Arudcoputer was more like a helicopter, so I bought a Futaba defaulted for a helicopter. But then I learned more and realized that airplane mode would probably be better, so I switched the Futaba's mode over to airplane mode (it's capable of both, but it came with helicopter by default).

When you say, "RC setup wrong", do you mean I have things plugged into the wrong channels on the Rx or that the RC Rx needs to be re-configured in some way or that I didn't initialize properly in the Configurator? Or perhaps any/all of the above?

ModeratorPermalink Reply by John Church on October 9, 2010 at 1:17pm
Hi,
The sure-fire way to see if everything is responding/spinning the right direction is to get your safety gear on and hold the quad above your head and apply throttle. Also raise throttle to 25-50% and check control response from each stick. See if you can even feel it trying to pull away. Please post results of this test.
Permalink Reply by Dror Caspi on October 9, 2010 at 1:40pm
Check your rotation directions! From your description it sounds like all the rotors are spinning in the opposite to what they're supposed to do, and your thrust is downwards.

Dror
Permalink Reply by Robert Beatty on October 9, 2010 at 6:52pm
I have now removed the propellers and checked the rotational direction of the motors. Front and Back are CW, Left and Right are CCW, which I believe to be correct.

I have also checked to make sure that each ESC is plugged into the correct pins on the APM/IMU and that the Rx channels are plugged into the correct pins on the APM/IMU.

Can someone confirm that all four propellers should be mounted with the lettering facing upward?

JDronesPermalink Reply by Jani Hirvinen on October 9, 2010 at 7:43pm
All propellers should be mounted letters facing up. You cannot make propeller are a pusher by just turning it upside down. You need to have propellers that are made to be pushers and pullers already on factory.

If you motor rotations are as marked in Wiki pages. And you have checked that they really spin that way eg Front/Rear CW, Left/Right CCW. Correct way to mount your propellers is that they all "push" air down that tries to get up.

Here is a picture how Pusher and Puller looks next to each other. (These props will be on our shop in few weeks too)

Permalink Reply by Robert Beatty on October 9, 2010 at 8:03pm
OK, thanks for that confirmation, Jani. All my propellers/pushers are facing with lettering up and they are in the right positions and the motors are turning the correct directions. I have it setup like the Wiki pages.

With the propellers off, I hooked the unit back up to the configurator and re-did the calibration process. After I completed the calibration process, I clicked the Update button, which I assume updates the microcontroller with the new information. I then ran through the Pre-Flight Test and everything checked out OK there, just as it did before. One thing that I did notice just before re-doing the calibration process was that the Trim on the throttle was set to 8 in the Tx, so I set that to 0 before doing anything else. I don't know if that would make a difference or not.

My unit is still on the bench right now. When I test it with the motors on, I still get the same behavior that when I increase throttle, and then also move the stick to the left and right at the same time, one or two of the side motors will stop, or one or two of the front/back motors will stop, almost like they want to alternate. Although sometimes I can get them all going at the same time. With the throttle on medium to strong, should any of the motors ever stop like?

Chris mentioned at the top that he thought it sounded like an RC problem. What should I look for in the transmitter that would cause this behavior?

JDronesPermalink Reply by Jani Hirvinen on October 9, 2010 at 11:33pm
on low throttle yes we still have some issues on motors that stops but after you give throttle more than 25% it should not happen unless you tilt quad -+90 degrees on your hand or rotate it 180°. But these "hand maneuvers" are not normal anyways.

Hmm can you also give some output examples from your serial monitor, hit 'S' in serial monitor and paste few lines of it. From there you should see also your radio values with 'U' command. 'X' stops sending those.
Permalink Reply by Robert Beatty on October 10, 2010 at 9:34am
Jani,

I've now run the tests you described. Sitting stationary, motors not powered, RC not on:

5,1,-1,-1,0,1,1,0,1040,1040,1040,1040,-38,11,443
5,1,-1,1,0,2,2,0,1040,1040,1040,1040,-38,12,444
5,2,0,-1,0,3,2,0,1040,1040,1040,1040,-39,12,444
5,1,-1,-1,0,5,3,0,1040,1040,1040,1040,-38,12,444
5,1,-1,0,0,6,3,0,1040,1040,1040,1040,-39,11,443
5,1,-1,0,0,6,4,0,1040,1040,1040,1040,-38,12,443
5,1,-2,-1,0,7,5,0,1040,1040,1040,1040,-38,11,444
5,1,-1,0,0,8,5,0,1040,1040,1040,1040,-39,11,445
5,0,-1,-1,0,9,5,0,1040,1040,1040,1040,-39,12,444
5,0,-1,-1,0,10,5,0,1040,1040,1040,1040,-40,11,445
5,1,-1,-1,0,10,6,0,1040,1040,1040,1040,-39,11,442
5,-1,-1,0,0,12,6,0,1040,1040,1040,1040,-38,11,442

With me rocking the unit manually with my hand (motors not powered, RC not on):

5,17,106,22,0,111,-75,0,1040,1040,1040,1040,114,18,431
5,-104,62,-61,0,169,-59,0,1040,1040,1040,1040,62,5,470
5,-116,48,-31,0,175,-61,0,1040,1040,1040,1040,35,-57,425
5,-101,27,28,0,168,-60,0,1040,1040,1040,1040,-2,-58,430
5,-66,88,-60,0,151,-101,0,1040,1040,1040,1040,16,-75,426
5,-113,88,-80,0,174,-101,0,1040,1040,1040,1040,13,-76,417
5,-161,113,2,0,197,-121,0,1040,1040,1040,1040,9,-78,472
5,-181,-62,-23,0,206,-35,0,1040,1040,1040,1040,-55,-128,404
5,-96,-58,-40,0,165,-32,0,1040,1040,1040,1040,-80,-148,395
5,-76,-63,-24,0,156,-17,0,1040,1040,1040,1040,-123,-76,450
5,-26,-79,32,0,132,-7,0,1040,1040,1040,1040,-109,-33,450
5,-64,-64,64,0,150,-13,0,1040,1040,1040,1040,-74,0,418
5,-47,-223,53,0,142,67,0,1040,1040,1040,1040,-50,51,378
5,-82,-225,3,0,159,88,0,1040,1040,1040,1040,-23,144,461
5,-78,-145,36,0,157,55,0,1040,1040,1040,1040,-22,127,408
5,-79,-104,12,0,157,39,0,1040,1040,1040,1040,-76,191,407
5,-58,73,28,0,147,-48,0,1040,1040,1040,1040,-96,203,435
5,-143,262,86,0,188,-158,0,1040,1040,1040,1040,-111,190,414
5,-259,100,66,0,244,-87,0,1040,1040,1040,1040,-110,104,392


On this one, I turned on the RC, armed the motors with the RC (although the motors were not powered), pushed the throttle slowly to max, then came down to 50%, then move the throttle stick to the right and left, then came down to 0% throttle.

1499,1496,1497,1106,1748,1247,1500,1500,1500
1499,1496,1497,1106,1748,1247,1500,1500,1500
1499,1496,1497,1106,1749,1247,1500,1500,1500
1499,1496,1497,1106,1749,1247,1500,1500,1500
1499,1496,1497,1106,1748,1247,1500,1500,1500
1502,1500,1501,1106,1748,1247,1500,1500,1500
1500,1499,1500,1106,1748,1247,1500,1500,1500
1502,1500,1501,1106,1748,1247,1500,1500,1500
1502,1500,1501,1106,1749,1247,1500,1500,1500
1500,1499,1499,1106,1748,1247,1500,1500,1500
1502,1500,1501,1106,1749,1246,1500,1500,1500
1502,1498,1499,1105,1749,1247,1500,1500,1500
1502,1500,1501,1105,1748,1247,1500,1500,1500
1502,1500,1501,1105,1748,1247,1500,1500,1500
1502,1500,1500,1115,1749,1247,1500,1500,1500
1500,1499,1500,1258,1748,1247,1500,1500,1500
1502,1498,1499,1269,1748,1247,1500,1500,1500
1502,1500,1501,1270,1748,1247,1500,1500,1500
1502,1500,1501,1271,1748,1247,1500,1500,1500
1502,1500,1501,1273,1748,1247,1500,1500,1500
1500,1501,1507,1275,1748,1247,1500,1500,1500
1502,1502,1504,1294,1748,1247,1500,1500,1500
1501,1502,1504,1314,1749,1247,1500,1500,1500
1500,1503,1504,1324,1749,1247,1500,1500,1500
1503,1501,1502,1355,1749,1247,1500,1500,1500
1503,1501,1502,1358,1748,1247,1500,1500,1500
1503,1501,1502,1358,1749,1246,1500,1500,1500
1503,1501,1501,1371,1749,1247,1500,1500,1500
1503,1501,1502,1403,1748,1247,1500,1500,1500
1503,1501,1502,1403,1748,1247,1500,1500,1500
1503,1501,1502,1425,1748,1246,1500,1500,1500
1503,1501,1501,1450,1748,1247,1500,1500,1500
1503,1500,1501,1471,1748,1247,1500,1500,1500
1501,1499,1500,1520,1748,1247,1500,1500,1500
1501,1500,1501,1538,1748,1247,1500,1500,1500
1502,1500,1501,1541,1748,1246,1500,1500,1500
1502,1500,1501,1542,1748,1247,1500,1500,1500
1499,1497,1497,1540,1748,1247,1500,1500,1500
1499,1496,1497,1557,1749,1247,1500,1500,1500
1499,1496,1497,1661,1748,1247,1500,1500,1500
1499,1496,1497,1681,1748,1246,1500,1500,1500
1499,1496,1497,1692,1748,1247,1500,1500,1500
1499,1496,1497,1700,1748,1247,1500,1500,1500
1499,1496,1497,1728,1748,1247,1500,1500,1500
1499,1496,1497,1801,1748,1247,1500,1500,1500
1499,1496,1497,1835,1749,1247,1500,1500,1500
1499,1496,1497,1916,1748,1247,1500,1500,1500
1499,1496,1497,1930,1749,1247,1500,1500,1500
1499,1496,1497,1931,1749,1247,1500,1500,1500
1499,1496,1497,1931,1749,1247,1500,1500,1500
1499,1496,1497,1931,1749,1247,1500,1500,1500
1499,1496,1497,1931,1749,1247,1500,1500,1500
1499,1496,1497,1931,1749,1247,1500,1500,1500
1499,1496,1497,1915,1748,1247,1500,1500,1500
1503,1500,1501,1844,1748,1247,1500,1500,1500
1501,1499,1513,1778,1749,1246,1500,1500,1500
1499,1497,1516,1745,1748,1247,1500,1500,1500
1499,1496,1517,1721,1748,1247,1500,1500,1500
1499,1496,1541,1698,1748,1247,1500,1500,1500
1499,1496,1579,1696,1748,1247,1500,1500,1500
1499,1496,1705,1620,1749,1247,1500,1500,1500
1499,1496,1763,1605,1748,1247,1500,1500,1500
1499,1496,1827,1606,1754,1247,1500,1500,1500
1499,1496,1889,1607,1749,1247,1500,1500,1500
1499,1496,1937,1607,1748,1247,1500,1500,1500
1499,1496,1992,1608,1748,1247,1500,1500,1500
1499,1496,1996,1670,1748,1247,1500,1500,1500
1499,1496,1995,1704,1749,1247,1500,1500,1500
1499,1496,1996,1707,1748,1247,1500,1500,1500
1499,1496,1996,1683,1749,1247,1500,1500,1500
1499,1496,1948,1681,1748,1247,1500,1500,1500
1499,1496,1761,1682,1749,1247,1500,1500,1500
1499,1496,1667,1684,1748,1247,1500,1500,1500
1499,1496,1529,1713,1748,1247,1500,1500,1500
1499,1496,1499,1718,1749,1247,1500,1500,1500
1499,1497,1452,1725,1748,1247,1500,1500,1500
1499,1497,1409,1732,1748,1247,1500,1500,1500
1499,1497,1350,1733,1748,1247,1500,1500,1500
1499,1497,1291,1733,1748,1247,1500,1500,1500
1499,1497,1233,1734,1749,1247,1500,1500,1500
1499,1497,1178,1735,1748,1246,1500,1500,1500
1499,1497,1110,1742,1748,1247,1500,1500,1500
1499,1496,1031,1792,1748,1247,1500,1500,1500
1499,1496,1011,1794,1748,1247,1500,1500,1500
1499,1496,997,1787,1749,1247,1500,1500,1500
1499,1496,997,1788,1748,1246,1500,1500,1500
1499,1496,997,1788,1749,1247,1500,1500,1500
1499,1496,997,1784,1748,1247,1500,1500,1500
1499,1496,1057,1753,1749,1247,1500,1500,1500
1499,1496,1168,1726,1748,1254,1500,1500,1500
1499,1496,1223,1699,1748,1247,1500,1500,1500
1499,1496,1310,1667,1748,1247,1500,1500,1500
1499,1496,1364,1666,1748,1247,1500,1500,1500
1499,1496,1404,1664,1748,1247,1500,1500,1500
1499,1496,1437,1663,1748,1247,1500,1500,1500
1501,1496,1511,1673,1749,1247,1500,1500,1500
1499,1497,1500,1674,1749,1247,1500,1500,1500
1500,1497,1498,1676,1749,1247,1500,1500,1500
1500,1496,1497,1675,1748,1247,1500,1500,1500
1500,1497,1498,1674,1748,1247,1500,1500,1500
1501,1498,1499,1674,1748,1247,1500,1500,1500

Here is a section of the last one I did, which is the same as above, but with the lip connected to the ESC/motors this time (although, when I turn on the U command, the motors don't actually spin):

1499,1496,1996,1652,1748,1247,1500,1500,1500
1499,1496,1996,1652,1749,1247,1500,1500,1500
1499,1496,1934,1652,1748,1247,1500,1500,1500
1499,1496,1860,1649,1748,1247,1500,1500,1500
1499,1496,1734,1647,1748,1247,1500,1500,1500
1499,1496,1577,1620,1748,1247,1500,1500,1500
1500,1496,1467,1585,1749,1247,1500,1500,1500
1499,1497,1426,1550,1748,1247,1500,1500,1500
1500,1497,1378,1542,1748,1247,1500,1500,1500
1499,1496,1319,1539,1748,1247,1500,1500,1500
1500,1496,1246,1513,1748,1247,1500,1500,1500
1500,1496,1158,1458,1749,1246,1500,1500,1500
1499,1496,1084,1447,1749,1247,1500,1500,1500
1499,1496,1043,1450,1748,1247,1500,1500,1500
1499,1497,1008,1452,1748,1247,1500,1500,1500
Permalink Reply by Greg Fletcher on October 9, 2010 at 7:57pm
Sounds like a yaw control problem. Thats how a quad controls yaw by increasing one set of opposing props while decreasing the other set. This creates differential torque around the vertical axis with out tilting the x or y axes. You seem to have way to much yaw control - all left or all right. There must be a yaw gain setting way off by a couple of decimal places. Re-check your configuration an look for the yaw gain? I haven't tried a quad yet so am not familiar with the configurator, but I know how a quad works.

ModeratorPermalink Reply by John Church on October 9, 2010 at 9:14pm
OK- Post a picture?

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