| 摘要 |
A vehicle steer by wire system which has a steering wheel 40 for setting a desired turn angle of a vehicle wheel 13, a steering wheel turn sensor 42 for sensing the desired turn angle, a hydraulic steering actuator 12 for turning the wheel, a wheel turn sensor 43 for sensing the current wheel turn angle and a control unit 23 for receiving the desired turn angle and current wheel turn angle signals. An electronically controlled steering actuator control valve means 14 is provided for supplying pressurised fluid to the steering actuator 12 via a steering circuit in response to signals from the control unit 23 to turn the wheel to the desired turn angle. A hydraulic motor 18 connected with the steering wheel 40 is provided to provide steering feedback to the steering wheel via a feedback circuit 17 which includes an electrically controlled hydraulic feedback control valve means 21,24 which directs fluid to and from the hydraulic motor 18 in response to the signals from the control unit 23 to generate the steering feedback. The steering system has a fail-safe mode in which fluid pressure from the hydraulic motor 18 provides steering of the wheel 13 in the event of a failure to electronically actuate the steering actuator control valve means 14. |
