IMU position data (x,y,z) is all zero

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jbroo163
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Joined: Tue Feb 01, 2022 9:51 pm

IMU position data (x,y,z) is all zero

Post by jbroo163 »

We are seeing that the position values reported by the Hedge are all zero. Initially we did not have IMU reporting enabled in the hedge's interface settings. After enabling all of those options we saw that fusion messages were being sent to the hedge. The quarternion values were populated, but the X,Y,Z values were still all zero. The raw data coming from the Hedge is zero so this is not due to a data parsing issue (although there is a separate data parsing issue, see below). We see that in the dashboard the Hedge has an "IMU" label below it's position values so I believe that the IMU is in fact running (it is enabled). I'm guessing that there's a bug somewhere preventing the reporting from being properly enabled, but obviously the Hedge code is closed source so I can't verify that.

- Software Version: 7.0
- Non-inverse architecture
- Using C API in Linux and Linux x86 dashboard

Note: There is a separate bug that I noticed which to be clear is NOT the root cause of our issue, but just something else I noticed while debugging. In marvelmind.c process_imu_fusion_datagram, the Y and Z data is parsed as 16 bit integers rather than 32 bit integers. The raw data indexing is presumably correct (4 byte separation), and since the data is encoded as little endian you are going to end up reading the 2 least significant bytes of each value, which I believe will just constrain your range of values to +/- 32,767 mm.

https://github.com/MarvelmindRobotics/m ... c/issues/2

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