MPU6000 and VR

Hello,

While trying to test the MPU6000 using a shaker, we have encountered VR or Vibration Rectification on the Z axis.

We used SWEEP as well as RANDOM vibration patterns.

VR is a phenomenon where for some complicated reason the mean value (or DC value) of the measured acceleration is biased or changed even though the input acceleration is symmetric with respect to zero.

The MPU6000 encounters VR at 7 G-rms noise vibration and 9G-peak sine wave sweep. We placed the MPU so that the Z-axis felt 1g. We then used different vibration patterns ,on the z axis,which were all symmetric with respect to zero. We configured the MPU to work in a 4g range with 40Hz SR and 5HZ DLPF in normal power mode.

We know VR exists in every ACC MEMS. We didnt find any information regarding the VR in the datasheet of the MPU.

Did you encounter any VR at your tests when you qualified the sensor? Any chance this VR is actually something else? We used the shaker for quite some time now, and only recently discovered this phenomenon- when we began testing the Z axis.

Thanks,
John