Will it Balance? Learning how to balance a Famous Hobby Gimbal
Before I jump into wiring and programing this beast I really wanted to have a greater understanding of the mechanical aspects of things, where and how to make adjustments and just how difficult will it is to balance.
I know from my experience working with the DJI Zenmuse gimbal that being slightly unbalanced or having any point of sticking or binding, however slight, will result in vibrations in your images. In order to get incredibly smooth images your gimbal has to be in top working condition: Perfectly Smooth. (I realize there are other contributing factors to vibs related to the multi-rotor, but I’m not concerned with that yet)
This gimbal is designed for large cameras such as the Red or Sony FS700, but I’m working with my Canon 6D today just to get the hang of things. I’ve also removed the arched tilt bar thingy (mentioned in Day 2), the gimbal will work fine without it and for the size and weight of the 6D I think it’s overkill. I anticipate that I’ll have to figure out how to get that mounted eventually, but for now I’m pulling it out of the equation. For now I’m also ignoring the pan axis, I’ve taped the tube attached to the motor that controls pan to the handlebar to prevent it from swinging.
Before heading to the workbench I did a quick Google “how to balance gimbal” and came up with two videos that were helpful:
- From AerialPixel (where I’ve purchased my Alexmos board):
Balancing DSLR Cameras for Alexmos Brushless Gimbals
- From GetFPV (I’ve ordered gear from these guys too):
AlexMos Gimbal Pre-Tuning Step-by-Step Set-up Guide
The second video will be more applicable later on, but since I came across it and it was loaded with helpful information I’m leaving it in.
Here’s what I’ve picked up from watching these videos:
- First balance the roll, balance the tilt axis second
- A correctly balanced gimbal will remain in any position that you put it
- Motion on all axis must be perfectly smooth, no sticking points, no binding
From my experience with the Zenmuse I knew that balancing can be a very finicky process, and I was presently surprised at how quickly I was able to get things in the ball park and then fine-tune. It still took me a few hours, but much less time than anticipated.
(continued below gallery)
The digital calipers and the digital pitch gauge mentioned in Day 2 came in really handy today. Most adjustments on the gimbal need to be made symmetrically on both sides of the gimbal, using the calipers I was able to measure the adjustments to ensure they matched. The horizontal arms have the potential to droop, using the digital pitch gauge I can compare their angle with the handle bar to ensure they are perfectly parallel.
Because my camera is much smaller, I adjusted the depth of the tilt supports. Two screws on each side hold these supports onto the tilt pivots. The right pivot has wires running through it which I had to remove to make this adjustment. What I discovered (and what I suspected) is that these wires are running through some spinny thingy (I tried googling to figure out what this is called. EDIT: Thanks to Klaus in the comments I’ve learned that this is called a “slip ring”) that allow them to rotate freely.
EDIT: Kopterworx has an example of a slip ring with 10 cables which fits inside of a gimbal motor:
If this is your first time balancing a gimbal take your time, think carefully about what adjustments need to be made to make things balance, it’s not always obvious. Make small adjustments, using a measuring tool, and don’t try to get it perfect all at once, you’ll have to jump around dialing it in as you go.
Also remember to remove the lens cap! Keep in mind that wires, batteries, lens caps, memory cards all make a huge difference in how it balances.