ByAllen Fan, Field Applications Engineer, ADI China Automotive Sales Team

Tilt measurement accuracy can easily be improved with a combined part of accelerometer and gyroscope. Frequently found in vehicles, single- or dual-axis accelerometers measure inclination of the electric park brakes (EPBs) that hold a vehicle stationary. For this, an X-/Y- or Z-axis low-g accelerometer is typically placed in a dedicated module of the EPB control unit.

Most modern vehicles also have ESC (electronic stability control) function that prevents the vehicle from side slipping and rolling over. ECS tends to combine a low-g accelerometer and gyroscope in a single chip, removing the need for a standalone EPB module, which avoids adding to the car’s size, weight and cost. However, because a combo part is typically used for ESC, it’s not necessarily optimised for tilt sensing, which makes it less accurate for this type measurement.

In a combo part, the X-axis is typically used for tilt measurement, whereas in EPB modules, traditional low-g accelerometers use the z-axis that’s installed vertically in the engine compartment. The sensing axis should be placed perpendicular to gravity for better accuracy.