| 摘要 |
PURPOSE:To hold energy consumption and step motor's heat generation down to the minimum by controlling the current value of a driving pulse to be fed to the step motor from a drive circuit to be larger when viscosity in a hydraulic fluid is high, namely, when load of the step motor is large enough. CONSTITUTION:This steering system is provided with a front-wheel steering angle sensor 61, a car speed sensor 62, a yaw rate sensor 63, a temperature (viscosity) sensor 64 and a turning angle sensor 65, and it takes their detected signals into a central processing unit 66c, determining a current value I conformed to a temperature T after referring to a first table in a read-only memory 66b, while it outputs a driving current control signal showing the said current value I to a drive circuit 67. Since this current value I is one that is reduced in proportion as making the temperature T is relation to viscosity in a hydraulic fluid go up, the drive circuit 67 comes to reduce the current value of the driving pulse into a step motor 56 according to a rise in the temperature T. In succession, a front-wheel steering angle factor conformed to a car speed V and a yaw rate factor are determined, through which a desired rear- wheel steering angle is calculated. |
