LSM6DSV80X SFLP quaternion adaptation issue for racket game posture reset
Hi ST team,
We are using the LSM6DSV80X SFLP quaternion output for a smart racket project. The quaternion is used by the mobile APP to control the game character posture.
During our test, we found that when the racket is powered on in a flat/horizontal position, the SFLP Yaw output can stay close to 0°, which is expected. However, when the racket is powered on or reset in a tilted position, the Yaw value is affected by the current Pitch/Roll posture and cannot remain at 0°.
For example, when the racket is powered on in a tilted position, the output is:
Roll = -0.58°
Pitch = -37.61°
Yaw = -9.40°
For our racket game application, the expected behavior is:
When the game starts or when the user performs posture reset, the current racket facing direction should be defined as the game coordinate system Yaw = 0°. At the same time, Roll and Pitch should still reflect the real physical tilt of the racket.
So the requirement is not a full orientation reset. We only need a Yaw-only reset:
- Yaw should be reset to 0° at game start/reset;
- Roll and Pitch should keep following the real racket posture;
- The initial tilted Roll/Pitch should not be reset to 0°.
Currently, we cannot find a related SFLP register configuration to achieve this behavior directly. Therefore, we would like to ask whether ST can provide a recommended quaternion post-processing method for this use case.
Could you please help provide:
- A yaw-only reset algorithm based on the SFLP quaternion output;
- The correct method to remove only the initial Yaw offset without affecting Roll/Pitch;
- The recommended coordinate system definition and quaternion multiplication order;
- C reference code or pseudocode that we can integrate into the customer firmware or APP side.
This issue is important for the smart racket game posture alignment, because the current SFLP output cannot directly meet the expected game coordinate reset behavior when the racket starts from a tilted posture.
