A fault diagnosis system for a yaw rate sensor

摘要

A monitor for a fault in sensor (1), for yaw in a vehicle controlled by a four-wheel steering system, compares the sensor output signal psi SENS with a value psi KALM derived directly from the differing speeds of the non-driven wheels (4R,4L) during turning. The derived value psi KALM is processed to take account of a number of relevant variables eg. steering (6) and rear-wheel (7) orientation and particularly the roughness of the terrain (14). The difference psi S-ENS - psi KALM is established by the module (2) and appears as an error psi ER for comparison with one of two threshold levels psi SHF in the diagnostic unit (3) depending on rough or smooth terrain.