In an actual aircraft where the vibration can be transferred to the control via the wiring it might make a difference. But it appears in this case the vibration is being directly applied to the control itself so I think the stiff USB cable has minimal effect for the test.
I think it is pretty well known that the V3/V3x will handle darn near anything on piston helicopters. I was running this one tonight, breaking in a new engine. That V3x is mounted on a homemade aluminum mount above the tail box, stuck to the aluminum plate with two strips of body mounting tape (the stuff they use to stick body moldings on cars and you have to use a prybar to get it off). It never clips the IMU’s even running it without blades on the ground, and zero drift on the attitude solution. Doing that will blow most other flight controls all to hell and the swashplate will be tipping back and forth like it’s nuts from the vibration. Engine is running at 10,000 rpm in this shot.
IMO this is the best test platform. I’m not even sure a speaker can simulate the vibrations of a real aircraft. Because the real aircraft has components all turning at different speeds and simultaneous different frequencies. You can pick the worst one and notch it and try to attenuate it in software. But that helicopter has five different shafts, all turning at different speeds in the transmission and driveline. From 160 some Hz from the engine to very high frequency vibrations from high-speed gear teeth mesh. In the end the flight control is either good and it handles it, or it don’t. You can’t “fix it” in software.
Have you noticed that when pixhack V3 is compared with V5 +, it has a value of 20 instead of 27 at 120Hz? This is the question I met when testing. If the test is standard, should it be 20 or 27? If the sensor is normal, it indicates that the force applied to the flight control during the test is not consistent. This makes me quite confused because I want to improve the shock absorption mode of IMU. If there is no definite standard, it has no reference significance. In addition, if you want more accurate results, my suggestion is to perform FFT on its log and observe its resonance frequency. Sometimes, the resonance frequency of IMU is higher than that of aircraft. Although it has certain damping effect, it is not a good thing. The correct damping method should be that the resonance frequency of IMU needs to be lower than that of aircraft.
Have you ever FFT the log? Through FFT, you can know the frequency of vibration on the aircraft and analyze the damping effect of different flight controllers
Interesting testing and discussion.
It seams like I did every possible mistake in building my Heli.
I used a clone Trex 700 (Hobbyking Assault 700 DFC) and replaced most of it to original Align part due to vibrations (bent shaft, poor parts quality, etc.)
Now I can see that the PH2.1 is the worse FC for helicopters.
So, now I’m working on a new Heli (I have the Gaui X7 frame which is a very solid frame) and would like to choose a FC.
The V3 cost around 350 USD (with Aluminium case) and the V3x is about 200 USD for all pack. Is it worth the extra 150 USD ?
Is there other good options for FC?
