DEVICE FOR ESTIMATING YAW RATE AND DIAGNOSING YAW RATE SENSOR TROUBLE

PURPOSE: To obtain highly accurate estimation values of yaw rate without phase delay and diagnosing trouble of yaw rate sensor with high accuracy. CONSTITUTION: A Karlman's filter 4 is provided to input a stearing angle signal θH and a rear stearing angle signal θR, and a static yaw rate estimation signal γW obtained based on converting speed difference between right and left rear wheels using a gain establishing device 6 for converting the yaw rate, while output a linear estimation value γK estimated from a numerical model by which behavior of a vehicle body is presented. When deviation between the estimation values γW and γK is not less than a threshold value, a highly accurate estimation value of the yaw rate can be obtained by correcting the linear estimation value γK, through for the case of an unusual driving condition, such as drifting. It is also possible to diagnose trouble using such estimation value. Further, it is possible to diagnose the trouble using a comparator by comparing an estimation value, comprising the difference between the yaw rate value detected by the sensor and the one estimated, with a reference threshold value, while in some abnormal state, it is effective to correct the reference threshold value for accomplishing the trouble diagnosis with higher accuracy.