Low frequency problems

Ben has found that when impacting the housing from the ends, he is getting a low frequency vibration of about 25Hz on sensors 3 and 4. This is happening regardless of which end is impacted.

results for impact from sensor 3 and 4 end (motor end of base)



results for impact from sensor 1 and 2 end (brake end of base)



for all these ffts we have decided to use the "short" version of the time domain signals (only cropped to the left) rather than the "shorter" version of the time domain signal (cropped left and right). Using N=8192 for the fft effectively crops the right hand side.




Possible problems

Firstly we checked that all the sensor bolts were tight (they were).

Next, to detemine if it was a sensor/ housing issue or a base issue, we bolted the housing and sensors on to the housing rotated by 180 degrees.

Below are the power spectrums for an impact near 3 and 4 (brake end of base)



impact near sensors 1 and 2 (motor end of base)