Abstract: A steering system functions in accordance with the “steer by wire” concept and has a normal operating system without positive coupling between the steering handle and the steered vehicle wheels, as well as an emergency operating system, which functions with positive coupling between the steered vehicle wheels and the steering handle. An auxiliary operating system is additionally provided, which, in response to malfunctions of the normal operating system, assumes its tasks and, in a transitional phase, adapts the performance characteristics of the steering system to those of the emergency system, which is switched on upon conclusion of the transitional phase. Thus, at the transition from the normal operating system to the emergency operating system, the driver is given time to become accustomed to the other steering performance.

Abstract: A steering system functions in accordance with the “steer by wire” concept and has a normal operating system without positive coupling between the steering handle and the steered vehicle wheels, as well as an emergency operating system, which functions with positive coupling between the steered vehicle wheels and the steering handle. An auxiliary operating system is additionally provided, which, in response to malfunctions of the normal operating system, assumes its tasks and, in a transitional phase, adapts the performance characteristics of the steering system to those of the emergency system, which is switched on upon conclusion of the transitional phase. Thus, at the transition from the normal operating system to the emergency operating system, the driver is given time to become accustomed to the other steering performance.

Abstract: In order to allow a traffic-lane following device in a vehicle to be used at relatively high vehicle speeds, a steering system is provided with a steering handle and a steering run which couples the steering handle to vehicle steered wheels. A servomotor is coupled to the steering run. A servovalve is arranged in the steering run and has a first control part (which is associated with a section on the steering handle side of the steering run) as well as a second control part (which is associated with a section on the vehicle steered wheel side of the steering run) to operate the servomotor as a function of relative movements between the control parts. An actuating drive is coupled to the section on the steering handle side of the steering run and is used to produce a steering force. A regulating and control arrangement uses a sensor system to determine required steering angle values which allow a traffic lane to be followed and uses a steering angle sensor to determine actual steering angle values.

Abstract: High functional reliability for a vehicle steering system that can be switched between a normal mode with a steer-by-wire level and an emergency mode with a fall-back level is achieved by providing that the fall-back level has a hydraulic system which contains a manual-side double-acting piston-cylinder unit which is actuated with a steering handle, e.g. steering wheel. The unit is positively coupled hydraulically to a wheel-side double-acting piston-cylinder unit which actuates steered vehicle wheels. A hydraulic charging system has a hydraulic pump, the inlet side of which is connected to a hydraulic-fluid reservoir. Switchable hydraulic couplings are provided for hydraulically coupling and decoupling the hydraulic system of the fall-back level and the hydraulic charging system to and from one another, respectively.