Sensor Noise

Hello All,I am working on my first drone, using an E-Flite UltraStick. So far the build has been going well. I developed a system for switching between radio and arduino control. I am working on developing my PIDs. I got a decent bench test in today. So I tried mounting my sensors to the plane to make sure I would not have issues with electronic interference. As it turns out, I am having mechanical interference. When I hold the sensors above the plane, no problems. As soon as the sensor make contact with the plane with the motor running, my sensor values go all over the place. What should I do!!!I am leaving for a trip to Idaho next weekend, where I was planning the maiden flight of my system. If need be I can order new sensors to be delivered to our property...I am using some osepp brand sensor I bought from frys. They run an ADXL345 (accelerometer) and MPU 3050(gyroscope).I wrote a program to try and filter the values. I filled an array of the 20 previous values and took the median. This worked on an earlier project but is no longer sufficient. In addition, it creates a sizable delay in my sensor values...What should I do?

I think this is why ardupilot and matrix pilot (etc) use some sophisticated stuff to deal with all the noise, but that's only part of the issue. I've no experience with the MPU sensor. But there may be some things you can do to help reduce vibration noise if that's the cause. Balance your prop. Change how and where you mount the sensor package. Look at what quadcopter people do for sensor mounting. There's probably a lot of advice on ariplane sensor mounting / vibration damping, vibration isolation. Another thing is if you increase the resonant frequency you can low pass filter in hardware or software.

The lag you mention in software filtering... if you can increase the sampling rate it allows you to filter the same amount but with less lag. Well, there's much more to it I'm sure... I guess it depends on the frequency range of the noise among other things. If you know the freq range then you can start to forumlate a plan -- this is my guess, anyway. I've not actually had to do this because the on my ground rover, I found gyro sensors that were reasonably vibration resistant and so it was pretty much a non-issue.

Is the noise so bad that your algorithm doesn't work?

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Jay D Oliver February 4, 2013 at 2:19pm

Hello Brett,

I'm working on an overwhelming project also, right now all my time is being divided between work and studying this project.

I saw you're using a MPU-3050 Gyro and I'm having the hardest time finding a good working arduino sketch for it.

Would you be kind to share your code for the MPU3050?
Bot Thoughts July 21, 2012 at 11:54pm

I think this is why ardupilot and matrix pilot (etc) use some sophisticated stuff to deal with all the noise, but that's only part of the issue. I've no experience with the MPU sensor. But there may be some things you can do to help reduce vibration noise if that's the cause. Balance your prop. Change how and where you mount the sensor package. Look at what quadcopter people do for sensor mounting. There's probably a lot of advice on ariplane sensor mounting / vibration damping, vibration isolation. Another thing is if you increase the resonant frequency you can low pass filter in hardware or software.

The lag you mention in software filtering... if you can increase the sampling rate it allows you to filter the same amount but with less lag. Well, there's much more to it I'm sure... I guess it depends on the frequency range of the noise among other things. If you know the freq range then you can start to forumlate a plan -- this is my guess, anyway. I've not actually had to do this because the on my ground rover, I found gyro sensors that were reasonably vibration resistant and so it was pretty much a non-issue.

Is the noise so bad that your algorithm doesn't work?

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Sensor Noise

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