Analytical Die Stress Modeling and Hysteresis Compensation in MEMS Sensors
Analytical die stress modeling isolates mechanical package strain from sensor signals while hysteresis compensation algorithms eliminate viscoelastic offset drift.
Hysteresis Compensation
Algorithmic Correction
An algorithmic correction is implemented in sensor microprocessors to eliminate the difference in output values for the same input value approached from different directions. Under this scheme, hysteresis compensation applies mathematical models to adjust the sensor output based on the history of the measured signal. This correction is essential in precise positioning systems and pressure measurements where direction-dependent offsets occur.
It restores accuracy without requiring physical changes to the sensing element.
Model Formulation
Mathematical representations of path-dependent behaviors are used to calculate the necessary offset adjustments in real time. Dynamic algorithms like the Preisach approach capture the memory effect of the material by tracking previous extreme values of the input signal. The hysteresis compensation must run continuously to maintain an accurate trace of these states.
This computation is performed by the embedded digital signal processor using pre-calibrated coefficient matrices. If the memory trace is lost due to a power cycle, the system must undergo a reset routine to establish a known starting state.
Calibration Routine
Calibration cycles with rising and falling steps define the characteristic error curve. Data points gathered from these cycles generate the coefficients required for the hysteresis compensation routine. Automated systems verify these values at reference temperatures before the sensor leaves the factory.
Temperature Sensitivity
Thermal variations alter the magnitude and shape of the loop. Accurate hysteresis compensation depends on temperature-dependent coefficients stored in the non-volatile memory.