Method for operating a steering system
A method for operating a steering system of a vehicle is proposed, wherein the steering system comprises a steering mechanism and at least one electric motor cooperating with the steering mechanism, wherein a moisture parameter correlating with the moisture in the steering system is determined, wherein, in order to determine the moisture parameter, the steering mechanism is brought into a defined test position and/or blocked in the test position, and the electric motor is actuated with an excitation signal, and wherein the moisture parameter is determined in that, during the actuation of the electric motor with the excitation signal, a motor torque of the electric motor and a rotor position angle of the electric motor is monitored and a change in the motor torque is evaluated according to the rotor position angle.
1 . A method for operating a steering system of a vehicle, wherein the steering system comprises a steering mechanism and at least one electric motor cooperating with the steering mechanism, the method comprising:
determining a moisture parameter correlating with a moisture in the steering system by, bringing the steering mechanism into a defined test position and/or blocking the steering mechanism in the defined test position,
actuating the electric motor with an excitation signal, and
determining the moisture parameter by monitoring a motor torque of the electric motor and a rotor position angle of the electric motor during the actuation of the electric motor with the excitation signal, and by evaluating a change in the motor torque according to the rotor position angle,
wherein at least one control parameter of a steering controller of the steering system for actuating the electric motor is adapted based on the moisture parameter.
2 . The method according to claim 1 , wherein the moisture parameter is determined using a derivative of the motor torque according to the rotor position angle or a difference quotient of motor torque and rotor position angle.
3 . The method according to claim 1 , the determining the moisture parameter further comprising:
comparing the change in the motor torque according to the rotor position angle with a reference value.
4 . The method according to claim 1 , wherein a linearization is used to determine the moisture parameter.
5 . The method according to claim 1 , wherein a current temperature is taken into account when determining the moisture parameter.
6 . The method according to claim 1 , wherein:
the moisture parameter is determined in a high load range; and
the electric motor is actuated by the excitation signal such that the motor torque is within an upper half of a nominal range of the electric motor.
7 . The method according to claim 1 , wherein the electric motor is actuated by the excitation signal such that the motor torque is continuously increased up to a maximum motor torque.
8 . The method according to claim 7 , wherein:
the motor torque is continuously increased in both steering directions with the steering mechanism blocked in the test position; or
the motor torque is continuously increased in one steering direction up to the maximum motor torque with the steering mechanism not blocked in the test position.
9 . A method for operating a steering system of a vehicle, wherein the steering system comprises a steering mechanism and at least one electric motor cooperating with the steering mechanism, the method comprising:
determining a moisture parameter correlating with a moisture in the steering system by, bringing the steering mechanism into a defined test position and/or blocking the steering mechanism in the defined test position,
actuating the electric motor with an excitation signal, and
determining the moisture parameter by monitoring a motor torque of the electric motor and a rotor position angle of the electric motor during the actuation of the electric motor with the excitation signal, and by evaluating a change in the motor torque according to the rotor position angle,
wherein the moisture parameter is compared with a limit value; and
wherein a safety measure is initiated in response to the moisture parameter falling below or exceeding the limit value.
10 . The method according to claim 1 , wherein the moisture parameter is determined when the vehicle is stationary and/or in a parked state of the vehicle.
11 . The method according to claim 1 , wherein the moisture parameter is determined at regular time intervals to monitor a change in the moisture parameter.
12 . The method according to claim 1 , wherein:
the steering mechanism comprises at least one steering assembly configured as a servo train;
a steering regulator element of the servo train is positioned in a region of a mechanical end stop of the steering system to determine the moisture parameter; and
the electric motor is actuated by the excitation signal such that the motor torque is continuously increased in a direction of the mechanical end stop up to a maximum motor torque.
13 . The method according to claim 1 , wherein:
the steering mechanism comprises at least one steering assembly configured as a sensor train;
the sensor train is blocked in a straight-ahead position to determine the moisture parameter; and
the electric motor is actuated by the excitation signal such that the motor torque is continuously increased in both steering directions up to a maximum motor torque.
14 . The method according to claim 1 , wherein;
the steering mechanism comprises at least one steering assembly configured as a vehicle axle or part of a vehicle axle;
at least one vehicle wheel is blocked to determine the moisture parameter; and
the electric motor is actuated by the excitation signal such that the motor torque is continuously increased in both steering directions up to a maximum motor torque.
15 . A processor configured to perform the method according to claim 1 .
16 . A steering system with a steering mechanism, with at least one electric motor cooperating with the steering mechanism and with a processor according to claim 15 .
17 . A motor vehicle, with a steering system according to claim 16 .