Hi,
We are using a LSM6DSV16X unit to track pitch and roll in our product based on the quaternions reported by the unit's SFLP algorithm (High Accuracy ODR 120Hz)
During the operation and in what seem to be arbitrary times, the pitch and roll signals for such unit present some unexpected overshoot or oscillation (see below) before returning to the expected value.
The graph above shows the IMU pitch signal (purple) with the reading of an absolute encoder (blue) and both signals should be fairly similar. The roll signal below, although not compared to any other signal, should maintain the same oscilatory behavior that is seen before and after the anomaly (vertical axis in º). At the moment of the anomaly, no special movement happened that could have caused such readings.
We have other LSM6DSV16X units in the same usecase and we do not see such behavior as of now.
We were doubting whether this could be a calibration problem of the IMU? Is there any calibration procedure you recommend for these IMU units?
Could this maybe be somehow related to the limitation in the quaternion components variables stored in half precision floats? https://community.st.com/t5/mems-sensors/lsm6dsv-half-precision-error-at-180-degrees/td-p/628771
Thank you in advance,
Joan
Hi,
I am posting the last results we got from a test we did comparing two units of the LSM6DSV16X IMU.
Note that the IMU measurements are done simultaneously on both IMUs.
From the data, it is clear that the gyro sensor mounted on the right side is not working properly, as it shows sudden spikes of 400 deg/s.
@Smithson If this spike were to come from an external source, we would see these spikes on both IMU sensors.
It is annoying that the embedded self-test feature is not able to detect that this IMU unit is not working properly :(
My suggestion is to put the four circled signal in CSV format and upload them here. Your issue does not appear Random, but I am only a pure mathematician who was led astray by the lure of money.
PS Who is the dude who changes and moves posts?
