The present invention relates to a method for operating a vehicle occupant protection device of a steer-by-wire steering system having the features of the preamble of claim 1, and to a steer-by-wire steering system for motor vehicles having the features of the preamble of claim 9.
In steer-by-wire steering systems, the position of the steered wheels is not coupled directly to the steering wheel. There is a connection between the steering wheel and the steered wheels by means of electrical signals. The driver's steering request is tapped by a steering angle sensor, and the position of the steered wheels is controlled in accordance with the driver's steering request by means of a steering actuator. A mechanical connection to the wheels is not provided. In order to simulate the reactions of the row on the steering wheel with steer-by-wire steering it is necessary to provide on the steering wheel or the steering column a feedback actuator (FBA) which impresses a steering sensation in accordance with the reactions of the steering handle.
Steer-by-wire steering systems have a multiplicity of driver assistance systems which can make an autonomous or semi-autonomous driving mode of the motor vehicle possible. In an autonomous driving mode, the motor vehicle can detect the surroundings of the motor vehicle using various sensors of the driver assistance system and can control the motor vehicle completely automatically by specifying predetermined values. In contrast, in a semi-autonomous driving mode, the driver assistance system steers automatically by specifying a predetermined steering lock angle. This is the case, for example, during a semi-autonomous parking process. In this context, the driver assistance system assumes the steering of the motor vehicle, and the driver activates the accelerator pedal and the brake. In contrast, in a manual driving mode the driver assumes the control of the motor vehicle.
In a vehicle head-on impact there are, depending on the driving mode, different conditions which should be ideally taken into account in order to protect the driver.
Laid-open Patent Application DE 10 2012 014 762 A1 discloses a vehicle occupant protection arrangement in which in the event of a vehicle head-on impact the steering wheel can be moved between a first and a second position before the driver impacts against the airbag. In this case, in the event of the vehicle head-on impact the steering wheel moves toward the driver. This movement is disadvantageous since the time between the vehicle head-on impact and the impacting of the driver against the steering wheel is reduced, which increases the risk of injury.
An object of the present invention is to specify a method for operating a vehicle occupant protection device which reduces the risk of injury to the driver.
This object is achieved by a method for operating a vehicle occupant protection device of a steer-by-wire steering system having the features of claim 1, and to a steer-by-wire steering system having the features of claim 9. Advantageous developments of the invention are specified in the dependent claims.
In the text which follows a situation in which the driver has gripped the steering wheel is referred to as a hands-on situation, and a situation in which the driver has not gripped the steering wheel is referred to as hands-free travel, that is to say a hands-off situation, which corresponds to the terms used in these technical fields.
A method for operating a vehicle occupant protection device of a steer-by-wire steering system is provided, wherein the steer-by-wire steering system comprises a steering wheel and an adjustable steering column which is connected to the steering wheel and can be adjusted between a retracted position and a deployed position by means of an adjustment mechanism, and wherein the steer-by-wire steering system has a feedback actuator to which a driver's request for a steering angle can be applied by a driver via the steering wheel, and which outputs a feedback signal to the steering wheel in response to the driver's request and a driving state of the motor vehicle. The method comprises the following steps: detecting an accident, detecting a hands-off situation or a hands-on situation, if a hands-off situation has been detected, moving the steering column into an accident position by means of the adjustment mechanism and triggering a steering wheel airbag during the adjustment process or after the adjustment process. The position of the steering wheel can therefore be adapted to the situation (hands-on or hands-off), as a result of which the risk of injury to the driver can be reduced. The adjustment mechanism adjusts the steering column, in particular in terms of length, here.
In the case in which a hands-on situation has been detected after detection of an accident, the steering wheel airbag is preferably triggered in the current position of the steering column. There is no provision for adjustment of the steering column here.
In a preferred embodiment, the accident position comprises the retracted position of the steering column.
The detected accident is preferably a vehicle head-on impact.
There can further be provision that for the case in which an accident has been detected and a hands-off situation has been detected, the steering wheel is rotated into an advantageous rotational position by means of the feedback actuator. It is preferred here if the advantageous rotational position is the neutral position of the steering wheel.
The method preferably comprises the step that when the driver impacts against the steering wheel, the energy which is input into the steering wheel is absorbed by means of an energy absorption device.
The adjustment mechanism preferably has an electric motor with a threaded rod drive which shifts an inner steering column tube of the steering column with respect to an outer steering column tube of the steering column.
Furthermore, a steer-by-wire steering system for a motor vehicle is provided, comprising an electronically controllable steering actuator which acts on steered wheels, a feedback actuator to which a driver's request for a steering angle can be applied by a driver via a steering wheel and which outputs a feedback signal to the steering wheel in response to the driver's request and a driving state of the motor vehicle, and an adjustable steering column which can be adjusted between a retracted position and a deployed position by means of an adjustment mechanism. The steer-by-wire steering system is configured here to carry out the method described above.
A preferred embodiment of the invention is explained in more detail below with reference to the drawings. Identical or identically acting components are designated with the same reference symbols in the figures. In the drawings:
There may be provision that in the case of an accident and in a hands-off situation the steering wheel is additionally moved into an advantageous rotational position. The feedback actuator 5 of the steering column 4 can be used for this purpose. In the case of an accident in a hands-off situation, the steering wheel 2 is preferably adjusted into a straight-ahead position. In this neutral position of the steering wheel, the steered wheels, if coupled mechanically to the steering wheel, are in a straight running position.
As shown in
The steering column 4 preferably has an energy absorption device which, in the case of a vehicle head-on impact absorbs in a controlled fashion the energy which is input into the steering wheel by the driver.
The adjustment of the steering column 4 into the accident position can be carried out by means of a magnetic, pneumatic, hydraulic, electromechanical or pyrotechnic device and is not limited to the adjustment mechanism illustrated in the figures.
Number | Date | Country | Kind |
---|---|---|---|
10 2018 102 103.8 | Jan 2018 | DE | national |
Filing Document | Filing Date | Country | Kind |
---|---|---|---|
PCT/EP2019/052047 | 1/29/2019 | WO | 00 |