Converting my CS gimbal to a brushless gimbal

Without ever actually testing a reduction setup I assumed that this would be the case. Thanks for your input Ozkan. I had a long back and forth discussion about this topic with a builder long before this discussion started.

The user explained that the larger full size helicopter heads (not sure if Cineflex is one) use a reduction setup...well their systems and equipment are specifically tune to work together, not the case with our ragtag mismatch of parts and electronics. The great torque gains trick you into thinking all is working as it should be.

The problem is, most guys building these gimbals are not the guys out in the field actually filming and using them. Most likely the feedback they get from build clients are guys who are probably just getting into aerial filming and haven't been around to witness the evolution from using tail gyros, infrared heat signature sensors, flight control boards, and finally the picloc and radian era so they are clueless as to what performance returns they should be receiving.

I've recently seen brushless setups that looked like radians and servos were used and I have seen brushless setups running the Alexmos board that looked like it came from a Cineflex equipped copter. You can achieve Cineflex-like results using the Alexmos board...I know firsthand.

As Ozkan said, an ideal setup would be direct on roll and tilt and belt on pan. If you can getaway without using belt at all and all axis are holding in the air, don't use it.

 

Thanks to everybody’s help here (especially you, Bill Collydas), I got my rig airborne today!

 

Not reading here for some time now but indeed is it nice to look at the board with yaw, tilt and roll
Dit try to find one some weeks ago....best place to get hold of one or two as of today?
Regards.
Janne

 

Tuukka,

Reducing pan axis with belt might help your problem. I've had few different alexmos setups and not a single one of them has worked well without belt reduction on pan, now i get really good results even on high 10-15m/s winds with lighter cameras.

GB85-1 motors are great but i would still reduce it on pan if using RED. Also you might need to replace vertical boom on gimbal with something stiffer than 1mm CF, i had oscillating problems red on board with CF tubes. I've now used alumimiun some of the booms and it is much stiffer now.

But one other thing, can i ask why you are flying over kids playground in Toinen linja?

Best,

Kari

 

Hi Kari are you using plastic or alu clamps?
Just using alu clamps instead of plastic ones makes the cintstar gimbal much stiffer!

Best ragards.

Janne

 

I'm using alu clamps for construction, plastic only for attaching accessories and for tilt motor cages for saving some weight (as it's not flexing anyway at all in that point). My gimbal is very stiff now with alu tubes and can tighten clamps more than with CF tubes, almost no flexing at all if 3kg weight on. But with CF vertical and backside horizontal roll cage tubes it was bouncing quite much and i also broke those CF tubes almost every time when tightening alu clamps "enough" for red or hitting gimbal bit harder. I even used steel tube first but it was a bit overkill for aerial rig, but if i was doing handheld gimbal, steel would be my choice in critical parts though.

Best,

Kari

 

Good video Steve and congrats on getting your bird in the air! Horizon roll is extremely pronounced in your video. There is also some issues with tilt at times not holding position. What is your settings and are you running a 3 axis setup?

Just FYI, I'm not on here putting down anyone's work, I've seen countless times folks post videos and no one ever responds with constructive criticism, which is necessary. Meanwhile the FreeFly Movi guys are looking at this stuff and chuckling.

 

Thanks for the comments. I have a long way to go with tuning, both the gimbal and the copter. Quite frankly I’m surprised that it worked as well as it did. This is a 2-axis gimbal. If you look at the Vimeo video in situ, I have quite a bit of info in the description. It’s running a Viacopter 2-axis board at 5s with 5208 motors on tilt and roll. Not going to post my gains right now because...well, they’re pretty far off I suspect. But like I said, I think they’re close to as good as my Radians are after a year of tuning.

 

Thanks Steve. Why are you running 5s? Running 4s at at the appropriate power is enough. 5s is unnecessary weight. I'm curious as to what would cause horizon roll in some videos, is it the "I" setting that's set too low? Most likely bad imu calibration and placement. Maybe if you upload your settings we could get it nailed down quickly.

 

I was originally intending to use a 5D Mark III, and Grayson from BrushlessGimbals.com implied that I’d have better motor performance with the 5s batteries. However, I’ve determined that my 4S Cinestar isn’t going to have quite enough horsepower to do what I want with the 5D, so I’m sticking with my GH3 for now. I would actually prefer to use 4s, but I’m on holiday away from my shop and I don’t have the smaller 4s batteries here. Today’s task is to get the tilt control on my mx20 to work. I have the GR24 output wired to the Alexmos board and the GUI seems like it’s set up right, but so far it doesn’t seem to hear the signals. I’ve always had a mental block about how the various parts of the PPM chain work, so this is no exception. I had it working properly with my Radians, but I am missing something.

 

Hi Bill,

Here's one pic i found. This was old setup with smaller motors and dd drive in pan without reduction, but you can see the booms what i mean at least. I've also tested this particular setup with scarlet quickly with small motors and they were just fine too, only pan didn't hold enough and in heavier winds i think i would have had problems, so 85-1 is a way to go.
I'll post more fresh pics when get back to studio after holiday.

Best,

Kari View attachment 3860

 

OK, I’m trying to get one of my Graupner mx20’s knobs to control the tilt (“pitch”) on the Viacopter Alexmos board.

• I made a servo cable with only signal to go from the GR-24 to the Alexmos board. (this is similar to how I had the Radians configured, and I was able to use the knob to tilt my Radian)
• I configured the GUI as shown below
• I configured the mx20 to output CTRL8 to channel 10
• AFAIK, I don’t have to do anything for the MK FC to allow this, right? I didn’t for the Radians...
• I am getting nothing

I’m not sure where the problem is...any ideas? Are there any good diagnostics to see if there’s a signal coming out of the RX? I have a voltmeter...
I’ve tried switching things around in the GUI, and nothing seems to be working. I’ve also tried channel 12 and CTRL7, but that didn’t work, either.
Here are some photos of my setup. Thanks!

 

Looks great for the first time out Steve!! Congrats.

 

Hmm..I wonder who that is!

 

I think I see why your roll isn't as solid as it should be. I see that you have your camera positioned closer to the left tilt motor cage, so I believe to correct this imbalance, you shifted the rear roll boom to the right? am I correct?

Try this, start our by centering the rear roll boom and use the camera weight to balance the roll axis. Mount the IMU on the tilt boom under the camera, centered with the roll axis. Also, perform another 6-point calibration.

IDK all I can come up with for the roll performance.

 

Thanks. I'll give that a shot.