| 摘要 |
PURPOSE:To improve the reliability of an apparatus by having a car speed detector and a car speed estimator and by using a car speed for drive control at the time of normal running and an estimated speed in place of the car speed, when abnormality occurs in a car speed signal. CONSTITUTION:The signal of a trailing-wheel speed detector 12 and that of a car speed estimator 14 are inputted to a switching logic circuit 15, a trailing- wheel speed is usually selected and outputted to a current command rate-of- change compensator 13, and the output to the current command rate-of-change compensator 13 is switched to an estimated car speed, when abnormality occurs in a trailing-wheel speed signal. In a switching logic, the trailing-wheel speed is the speed of a car body having a large mass and suffers no sudden change of time, and the deviation of a detection speed is monitored always and abnor mality is judged, when the deviation exceeds a specified value. |
