BMI270 Gyro issue :: drift in zero-rate offset

[JCAeron]

@BSTRobin @Minhwan @Vincent @o_o 

A random change is observed in the bias values of BMI270 Gyro data in its stable state. This change in the zero-rate offset values is random and can be seen on all X, Y, Z axes. Also I have used the latest BMI270 API version. BMI270 is tested on different boards to ensure that the issue is not board specific. The Gyro data output remains to be erratic. I am using only the Gyro for my application. Hope this is not the expected behaviour.

Any explanation on why is it so? Has anybody else observed this issue with BMI270?

Graphs attached below. Hope to get a reply back soon.

[JCAeron]

Yes BSTRobin 

We keep the Gyro off for 30 seconds before turning ON.

[BSTRobin]

Hello JCAeron,

We have contacted with you via email, you could give us more feedback in the email. Thanks.

[steve-landers]

We see something that sounds similar to the issue reported in this thread.  As you can see in the attached plot, we see sudden jumps on some gyroscope axes on the BMI270 (y axis - rad/s, x axis - gyro samples @ 100Hz).  What could cause this issue?

[JCAeron]

Hello Steve, @steve-landers 

The following points were suggested by Sensortec team. See if it helps.

Test environment

The device is mounted on a static platform while taking logs. All three axis data is recorded at the same time. The time difference between each run is 1 minutes and the device is turned OFF during this time. Axis 1, 2, 3 corresponds to sensor axis x, y, z respectively.

1. keep the sensor stationary;
2. record gyroscope data 1 minute;
3. close gyro off for 30 seconds before turning gyro on. Repeat step 2 four times to record the gyroscope data.

For step 3, did you add enough delay time until gyro stable after turning on gyro?

There were four version BMI270 sensor API on githubhttps://github.com/boschsensortec/BMI270-Sensor-API, which sensor API(BMI270 base, BMI270 context, BMI270 legacy, BMI270maximum FIFO) you used?

BMI270 (base)

• Any motion, No motion, Significant motion detectors
• Wrist worn Step counter and Step detector (Pedometer)
• Activity change recognition
• Still
• Walking
• Running
• Wrist gestures
• Push arm down
• Pivot up
• Wrist shake jiggle
• Flick in
• Flick out
• Wrist wear wake up

BMI270 Context

• Step counter and Step detector (Pedometer)
• Activity change recognition
• Still
• Walking
• Running

BMI270 Legacy

• Any motion, No motion, Significant motion detector
• Orientation detector (Advanced Potrait-Landscape)
• High-G, Low-G (Freefall) detector
• Flat detector
• Tap detection (Single, Double, Triple taps)
• Smartphone Step counter and Step detector (Pedometer)
• Activity change recognition
• Still
• Walking
• Running

BMI270 Maximum FIFO

• Supports a 6kB FIFO

[steve-landers]

We've seen this issue on 2 BMI270 units.  Units were entirely stationary, and were recorded exhibiting this behavior on different days.

We're currently using this version of the driver: https://github.com/boschsensortec/BMI270-Sensor-API/releases/tag/v2.63.1

When you were emailed by Bosch support, did they have any advice as far as potential sources of this issue, or potential fixes for it?