| 摘要 |
PURPOSE:To eliminate a centering spring at a steering angle control section, and make the steering angle control section and a drive source compact and lightweight by applying the constitution wherein even the steering angle of an abnormal steering system is calculated by a steering angle calculation section in a normal steering system for instruction to a steering angle control section, upon occurrence of failure. CONSTITUTION:A front wheel steering system is provided with a front wheel steering angle calculation section 6, and a rear wheel steering system with a rear wheel steering angle calculation section 7. Signals from a steering angle sensor 8 and a vehicle speed sensor 9 are respectively entered in the aforesaid calculation sections 6 and 7. A target steering angle is calculated in the aforesaid sections 6 and 7. Also, the steering angle calculation sections 6 and 7 make judgement as to whether the other calculation section 7 or 6 is normal or in failure, according to the reversal or non-reversal of a pulse signal to input sections 12 and 13 at every Tw second. If either calculation section is found to be out of order, steering angle calculation sections 14 and 15 for use upon occurrence of failure gradually change the target steering value of own steering system to an instruction value applicable at the time of failure, and also gradually changes the steering target value of the other steering system to an instruction value applicable at the time of failure. Finally, steering target value selector sections 18 and 19 supply the steering target value of the other steering system to steering control sections 5 and 4 as a rear wheel steering angle target value. |
