Accelerometers for vehicle chassis systems

Accelerometers are needed for providing a measure of vehicle body movement for use in electronically controlled suspension systems, passive restraint (e.g. air bag) systems and advanced braking systems. These accelerometers must accurately measure low level accelerations from DC (or close to DC) up to around 50 Hz or above depending on application. To do this the accelerometer must have a high sensitivity, the characteristics must be very stable in an automotive environment and the response must be essentially flat over the measurement frequency range. Additionally, the accelerometers required for crash sensing will probably require some form of self-diagnostics for early detection of sensor failure. The author briefly discusses the main accelerometer technologies: wound coil; piezoelectric thick film, thin film; and silicon. The application of accelerometers in vehicles is also discussed