Static Accelerometer Orientation Tumble Calibration Procedures
Static tumble calibration calculates accelerometer bias, scale factor, and cross-axis matrices by optimizing spatial vector residuals against local gravity.
Mechanical Settling Delay
Transient Wait
Configured wait periods programmed into automated testing sequences allow physical vibrations in a calibration stage to subside before data acquisition begins. Implementing a mechanical settling delay prevents the residual motion of the positioning stage from corrupting the static measurement of the sensor under test. This delay is placed immediately after any high-speed motion of the rotation table.
The duration of the pause is determined by the mechanical properties of the stage.
Calibration Latency
In high-throughput sensor production, the total test time is heavily influenced by these programmed pauses. If the mechanical settling delay is too long, the throughput of the calibration line decreases, raising the unit cost of each sensor. Conversely, a delay that is too short allows mechanical transients to enter the calibration dataset, leading to inaccurate bias calculations.
Engineers balance these priorities during the system design phase.
Vibration Attenuation
Structural resonances of the calibration fixture dictate the time needed for the system to reach static equilibrium. When a mechanical settling delay is active, the acceleration sensor output is monitored to ensure the amplitude of the residual vibration falls below the noise floor. High-frequency vibrations from the motor drive must decay fully before the sensor data is logged.
This process is verified by plotting the variance of the sensor signal over time after a motion block. If the variance remains high, the delay must be increased.
Trigger Threshold
Automation software utilizes these delays to guarantee that measurements are taken under static conditions. For a system with a mechanical settling delay, the trigger for data capture is delayed by a fixed interval or until the sensor output stabilizes. This step isolates the sensor from the dynamic effects of the positioning system.