I flew AC 3.0 (rc5) at Sparkfun which required me to rethink my vibration dampening strategy. In other words I had to go from no strategy to something very robust. If you want to fly 3.0 in any AP mode you'll need to consider at least some of these methods. Once upgraded, my copter was able to hold a 1 foot loiter box with the crappiest RCTimer props/motors they sell without issue.
Here was my shopping list:
http://www.rangevideo.com/accessories/vibration-mount.html
http://hobbyking.com/hobbyking/store/__8999__peel_n_stick_foam_tape_10x5inch_4mm_thick.html
http://store.3drobotics.com/products/m3-vibration-damper
I attached the latex foam to the vibration mount with super glue which worked nicely. Adding the dollar coins with super glue under the floating vibration mount also worked well.
Even with motors vibrating so much that they looked burry, it still held a great loiter.
Jason
Comments
When MultiWii gets inertial navigation that allows you to fly waypoints at 30m/s with 1m accuracy you'll need to put some foam under it as well. You don't need this level of vibration insulation for stabilized or acro flights. The setup I'm showing stops a wide range of frequencies. If there were simply one frequency, then the solution would be much different. Frequencies come and go for a wide variety of reasons that are frame, wind, and power related.
Jason
Hi Jason,
Pretty much used the same strategy for vibration on "Big Bertha" and "Big Ugly" builds over on the fixed wing blog.
Some clearer pictures I used on Big Ugly, a 50cc gasser, APM1.
The idea is to make the APM heavy, and mount it on soft foam.
I suppose some engineer type person could explain it all with inertia and elasticity modulus type hokey pokey, I just thumbsuck :-)
Vibration logs were quite acceptable.
Main reason for pulling the plug on this project, time, excessive vibration on the camera, and oil everywhere behind the engine :-(
Has anyone tried that mound: http://www.infinity-hobby.com/main/product_info.php?cPath=239_236&a...
Does it fit?
Hi Gary
Thanks for the info. Alt hold is working fine. Flying around doing sharp banks loses some height, but thats to be expected i guess.
Loiter is also fine when my compass is reading ok. Never really looked at the compass settings, will take a look at them soon.
I don't understand why my multiwiis sucesses without ANY anti-vibration systems on frame, but my APM2.0 still sucks with foam and all things mentionned above... Same MPU, so is the code making us using these (stupid) setup with foam we dont know frequencies they filter ><
Hi Dan,
IMU accel numbers of plus and minus 1.5 (in hover) should be fine that is equivalent to 0.15G.
Pretty much anything in the vicinity of plus and minus 2 (0.2G) or less ought to remove vibration from being a significant issue.
The time will come when we will probably want to do better, but until we have a genuinely engineered solution, shoot for + and - 2 or less = 0.2G.
Previously on 2.9 with Alt Hold Z inertial control only, a half G was considered sufficient, but now with full inertial compensation it is definitely better to get it below that and will definitely improve the stability of your copter to do so.
Im running 2.9.1b with the ardupilot stuck to a stack plate using double sided sticky foam. (one layer)
The stack plate is mounted to the frame using rubber mounts which are pretty stiff, designed for a PC water cooling pump. My logs show vibration of +- 1.5
What value are we looking for, for the 3.0 release?
And Randy has posted 3.0...
Read more here:
http://www.diydrones.com/forum/topics/arducopter-3-0-ready-for-wide...
By the way, I have also tried (soft) Sorbothane and while it helps, its results do not appear as good as the already mentioned Gels.
Personally, I would like to see 3DR stocking and promoting Kyosho Zeal Gel.
It is just the right thickness, not too soft, quite durable, very effective and has good double sided tape on both sides. And one hunk of it should be good for at least five or six flight controller mounting jobs.
It is almost the perfect real world product for this.
On my DJI 330 and 450 FlameWheels, a 3/4" square of Kyosho Zeal Gel under each corner of APM on one and PX4 on the other secured with foam under a Velcro strap which is loosely tightened yields ~0.1G vibrations which are more than adequate.
Moon and Alpha Gel also work fine.
I have used the the four O-ring suspension mount system too which can yield nearly as good results but requires careful "tuning" of O-ring cross section and tension.
It is also important to provide a bit of a strain relief loop in the wiring to prevent vibration transferred through the wires.
For the motor and prop balancing proponents: Of course that can help, but unless you are a fanatic, you still need the above types of anti vibration flight controller mounting to get into the best range for version 3.0.
Which is the less than 0.2G vibration (less than 2 (shown in meters per second with Earth Gravity being 9.8 (look at Z axis)) as measured at the accels on the RAW or IMU log).
-
1
-
2
of 2 Next