zomozoom November 10, 2015 at 07:59

“To collect a large copter without knowing anything about them?” - Yes, nonsense (Part 2)

It's time to talk about camera stabilization for the copter, namely about 3-axis suspensions that I installed on my hexacopter.

As I said earlier, assembling a copter is unlikely to be cheaper in the absence of the necessary knowledge. But ambition did the trick, and I decided it was time to switch from servo-to-gimbal to gimbal with brushless motors. We had them relatively recently and at the time of assembly there were not so many of them. It was possible to buy a ready-made suspension for about 20 thousand rubles. However, I decided that it would be cheaper to do it myself.

This time I approached the project more seriously. Designed a 3d suspension model based on analogues. Ordered 3 ipower 4008 150T * engines , carbon plates *2 mm thick, a controller for suspension on the ARMBGC website (there it was 2 times more expensive than in China, but a friend said that it was something better), and a vibration isolation board (not knowing which one I took, which one is suitable for a DSLR) .

The controller was a “red” main board, a sensor, and a 3rd axis board, which was mounted on top of the main board (convenient).

Without a machine at hand, all the details were cut out manually. There are no comments, I know that this is idiocy. And after a while the suspension was ready.

I wanted the suspension to rotate 360 degrees and the chassis did not interfere with the shooting. Then I decided to attach the “legs” to the 3rd axis so that they rotate with the camera and do not fall into the frame.

The suspension turned out to be normal. The camera was well balanced and it's time to install the electronics.

I will not stop for a long time on connecting and configuring the controller, since the setting for each suspension is individual. I can only say that the pitch and roll engines did their job relatively well, however, the yaw axis motor simply did not stretch the entire load with deviations of more than 20-30 degrees. Therefore, the 4008 engine was replaced with a 5208 180T.

In addition, the “whole” legs had a very bad effect on the yaw axis, as they resisted the whole plane with air during the flight and did not allow the suspension to work normally.

It became clear why on the "copters" the legs are made not whole but "frame" ... only the thin outline of the leg itself. Not wanting to cut anything else, I decided to simply remove them and launch the copter from my hands.

As a result, this suspension flew off for a rather long time.

By the way, the gimbal kit also included an AV converter for the Sony nex camera (since it does not have an analog video output) and a shooting mode switch (photo, video) and a receiver for controlling the gimbal.

For video transmission, a boscam transmitter * of 200 mw was used. The

suspension worked both with a 16 mm lens and with 16-55 ... but 50 mm worked more for show than for shooting quality ... I had to stabilize it programmatically.

And after a while I decided that it was time to buy another suspension. Which better stabilizes the picture and make it easier. The choice fell on such a 3-axis suspension * . An unfamiliar suspension company, MOY. Well, mine, then mine))

Advantages of the suspension:

1) Compact size.

2) It weighs 690 grams (600 lighter than the old suspension).

3) Closed motors. This is a really important indicator, since dust and dirt really worsen the suspension (I compare it with the old suspension with open engines).

4) The controller in a protective box.

5) The absence of the “right lever” of the gimbal makes it easy to configure the camera.

Cons of suspension:

1) A battery larger than 1000mah cannot be suspended (there simply is no space).

2) Ideal for a 16 mm lens, but for 18-55 there is not enough just a little hole in the mounting plate. As a result, the camera falls forward with the lens extended (when 55 mm). However, the engines still pull this imbalance to prove that below you will see a video without stabilization, shot at 50 mm.

3) The absence of the “right lever” of the suspension makes the camera less secure.

As a result, I got a good suspension for relatively little money and no problems.

And if with an old suspension the hexacopter flew like a loaded barge, now it is very fast and maneuverable.

Video in real speed + 3% stabilization.

By the way, the gimbal came quite quickly (unfortunately I won’t give a link to the seller, because he doesn’t already sell this gimbal) in such a cool box. Almost like an iPhone. :)

I can’t say that this is a “ready out of the box” suspension, since only 1 follow mode was configured and not very well tuned. As a result, I additionally configured the modes for different lenses and added the ability to control from the remote control. At the moment, I’m expecting a scarf to configure the suspension via Bluetooth * . As a result, you do not have to connect the wire to the controller each time and connect it to the computer. I must say right away that it’s better to do “quality” suspension settings because soldering the usb port on controllers is not so hot.

I came to this conclusion while setting up the old controller on the old suspension. While plugging the cord back and forth, the port fell off and inadvertently “slipped something.” As a result, even after soldering it back to the computer, this controller did not see it. The reason for this was the "black box" on the board. Thanks to the seller who agreed to send me this box for free (after all, replacing the controller would have cost a pretty penny). In the repair of mobile phones they soldered it to me for 200r. That is why I advise you to buy such a scarf for tuning via Bluetooth, because tuning is the thing: at home in front of the mirror it works according to one scenario, and in flight, when you are guided by the horizon, in a different way.

Now the suspension is not yet fully configured and does not require stabilization only when flying in calm weather with a 16 mm lens, and the horizon falls. The solution to the problem of blocking the horizon (as I understand it) is the “trust in the weights” parameter, but here you also need to know the balance between quality and the split of motors. Therefore, at this stage I’m not worried and I'm waiting for a scarf. :)

I want to note that in more modern versions of the controller Bluetooth is already built-in, so check this when ordering.

And, of course, the conclusion :

1) Assembling a gimbal on your own is not as easy as a copter. In addition, at the moment it is simply not advisable, because they are full on sale.

2) If you take the suspension, then only with closed motors, dust and dirt very negatively affect their work (especially random metal shavings). By the way, in the old version of the suspension, metal shavings often fell into the yaw axis engine ... literally 2-3 particles, while screwing bolts back and forth, disassembling, assembling, etc. As a result, these particles fell between the rotor and the motor stator and reduced its smoothness and created a "crack". Therefore, if your engine is “shooting” at your suspension, then this indicates “dirt” in the motors.

3) And another piece of advice not related to the suspension, but related to the converter for sony nex. At some point between the pilot and the operator the question of “communication” arises from a distance. That is, if the operator stands in place of the takeoff of the copter, and the pilot has gone a little further away for better visual control of the copter. For this purpose we have walkie-talkies. However, during operation at frequencies in the range of 400 MHz, this converter begins to freak out. The picture from the camera on the monitor is divided into 2 parts and swaps. For a long time they could not understand why such miracles were caused, but then it became clear that it was because of the walkie-talkies.

That's all I think. It seems that I did not forget to tell you anything. See the video from the copter below, and I went to write an article about something else)

And finally, the final list of my suspension components: