Method for reducing load in a steering system

Abstract

A method for reducing a load in a steering system (10), in particular during operation in a vehicle (12), is proposed, wherein a load caused by an external force action acting on the steering system (10) is determined and at least partially compensated for in at least one operating state by manipulating an actuator unit (14), and wherein the actuator unit (14) is manipulated in the operating state in such a way that an inertial effect of the steering system (10) related to the external force action is reduced.

Description

Technical Field

[0001] This invention relates to a method for reducing the load on a steering system. Furthermore, this invention relates to a controller having a computing unit for performing this method, and a vehicle having a computing unit for performing this method. Background Technology

[0002] Vehicles, and especially their steering systems, must be designed to have high load-bearing capacity in order to maintain functionality throughout their service life. This is particularly true when driving on rough roads, where very high loads are applied to the steering system, the load of which depends in particular on the magnitude and arrangement of the mass and inertia within the steering system, as well as the stiffness of the steering system. To prevent damage, components with excessively large mechanical dimensions are often used; however, this increases the weight of the steering system and raises costs. Summary of the Invention

[0003] The object of the present invention is particularly to provide a method for reducing the load on a steering system, which has improved characteristics in terms of efficiency. This object is achieved by a method for reducing the load on a steering system, particularly during operation in a vehicle, a controller having a computing unit for the method according to the invention, and a vehicle having a steering system including at least one actuator unit and a computing unit for executing the method according to the invention, while advantageous designs and improvements of the invention can be obtained from the technical solutions described below.

[0004] A method is proposed for reducing the load on the steering system, particularly during operation in a vehicle and advantageously in a motor vehicle. This method involves determining, in particular, the mechanical load on the steering system caused by external forces acting on it, and compensating for it at least partially and preferably at least substantially by manipulating an actuator unit in at least one operating state. Specifically, to at least partially compensate for the load, the actuator unit is manipulated in the operating state to reduce the inertial effects of the steering system associated with the external forces. Advantageously, the load caused by external forces acting on the steering system includes forces from the ground and / or the vehicle's surrounding environment. External forces causing the load on the steering system may, for example, be caused by uneven roads, potholes, overcoming obstacles, driving on rough roads, and / or other such specific events. Advantageously, the external forces differ from steering movements and / or, particularly, the direct forces exerted by the driver on the steering lever of the steering system. Furthermore, during operation, by manipulating the actuator unit, and particularly by at least partially compensating for the loads on components acting in connection with the steering system, such as tie rods and / or the chassis, the loads on the entire axle, especially the front axle, can be advantageously compensated. This design particularly improves efficiency, especially weight efficiency, component efficiency, and / or cost efficiency. Moreover, it advantageously increases the fatigue strength and / or service life of the vehicle, and especially the steering system.

[0005] The term "actuator unit" should be understood in particular as a unit at least partially configured to be electric and / or electronic, configured to provide torque and / or force and transmit it to at least one steering member. For this purpose, the actuator unit preferably includes at least one electric motor, which is particularly operatively connected to the steering member. Furthermore, the actuator unit is preferably part of the steering system. Moreover, "reducing the inertial effects of the steering system related to external forces" should be understood in particular as reducing the inertia of the steering system caused by external forces and / or the resistance of the steering system to external forces.

[0006] Furthermore, the vehicle and / or steering system may particularly include at least one computing unit, which is particularly configured to implement methods for reducing the load on the steering system. "Computing unit" should be understood in particular as an electrical and / or electronic unit having information input, information processing, and information output. The computing unit also advantageously has at least one processor, at least one operating memory, at least one input device and / or output device, at least one operating program, at least one control routine, at least one calculation routine, at least one monitoring routine, and / or at least one evaluation routine. In particular, the computing unit is at least configured to determine the load caused by external forces acting on the steering system. Furthermore, the computing unit is particularly configured to manipulate the actuator unit. In the present case, the computing unit is also particularly configured to manipulate the actuator unit in at least one operating state such that the inertial effect of the steering system related to external forces is reduced, and the load caused by external forces acting on the steering system is at least partially and preferably at least largely compensated. The computing unit is preferably integrated into the controller of the vehicle and / or steering system. The expression "at least largely" should be particularly understood here as at least 55%, advantageously at least 75%, and particularly advantageously at least 95%. "Setup" should be understood in particular as specifically programmed, designed and / or equipped. Object setup for a specific function should be understood in particular as the object satisfying and / or implementing that specific function in at least one application and / or runtime state.

[0007] Advantageously, in operation, a compensating torque and / or a compensating force to counteract the inertia of the steering system are generated by means of an actuator unit, and are applied to the steering system, particularly for at least partial compensation of the load. Specifically, the compensating torque and / or the compensating force generated by the actuator unit overcome the external force, allowing the steering system to advantageously move together with the external force, particularly in the direction of the force, and / or reducing the resistance of the steering system to the external force. Furthermore, it is particularly advantageous that the compensating torque and / or the compensating force generated by the actuator unit are introduced into the steering shaft and / or the steering transmission of the steering system. This allows for a particularly advantageous and simple reduction of the inertial effect of the steering system, and thus a reduction of the load on the steering system.

[0008] It is also proposed to use a load reduction function to manipulate the actuator unit in the operating state, wherein the load reduction function is activated and / or deactivated specifically according to the driving conditions, especially according to the current driving conditions. In particular, the load reduction function corresponds to a software algorithm preferably stored in the operating memory of the computing unit. Specifically, the computing unit is configured to manipulate the actuator unit in the operating state by means of the load reduction function, thereby generating a compensating torque and / or a compensating force to counteract the inertia of the steering system. Advantageously, in order to activate and / or deactivate the load reduction function, a load characteristic parameter is determined, and in particular compared with at least one limit value. In this document, "load characteristic parameter" should be understood in particular as a parameter that is at least related to the load, especially mechanical, on the steering system caused by external forces acting on it. In particular, at least by means of the load characteristic parameter, the load and / or load, especially mechanical, on the steering system and / or at least one steering member can be inferred, and / or the load and / or load, especially mechanical, on the steering system and / or at least one steering member can be determined. Furthermore, it is advantageous that the load characteristic parameter is related to the current driving conditions. Therefore, preferably, the current driving condition can be inferred and / or determined at least using load characteristic parameters. Furthermore, preferably, the load characteristic parameters are continuously determined, or monitored throughout the monitoring interval, and the changes in the load characteristic parameters over time are evaluated to determine the load and / or the current driving condition. This allows for a situational response to the load in the steering system. In particular, it ensures that under normal driving conditions where the load in the steering system is below its limit, no change in steering behavior and / or steering feel is perceived.

[0009] Furthermore, it is proposed to determine load parameters related to the load, particularly the load characteristic parameters already mentioned above, wherein if the load characteristic parameters exceed a first limit value, which is specifically defined and / or predeterminable, the load reduction function is activated, and if the load characteristic parameters are below a second limit value, which is specifically defined and / or predeterminable, the load reduction function is deactivated. In particular, the first and second limit values ​​can be different, wherein the second limit value is advantageously lower than the first limit value. This particularly enables advantageous hysteresis behavior. Furthermore, it can advantageously ensure that the load reduction function remains active even under load fluctuations. However, alternatively, the first and second limit values ​​can also be the same, thereby particularly enabling a prescribed response to external loads.

[0010] If the load reduction function, and in particular the compensating torque and / or compensating force, are manifested during activation and / or hidden during deactivation, then particularly inconspicuous activation and / or deactivation of the load reduction function can be achieved. The activation and / or deactivation of the load reduction function preferably occurs gradually or sequentially and particularly not abruptly. Particularly preferably, the activation and / or deactivation of the load reduction function is carried out by means of a continuous function, preferably differentiable at every point, particularly an asymptotic function, an sigmoid function, or advantageously a ramp function.

[0011] In a particularly preferred design, it is proposed that, during operation, at least one load present in the servo system is at least partially and preferably at least largely compensated by manipulating the actuator unit. The servo system is here specifically defined by the steering transmission of the steering system. This advantageously reduces the load in the servo system of the steering system.

[0012] Alternatively or additionally, it is proposed that, during operation, at least one load present in the steering system be compensated at least partially and preferably at least substantially by manipulating the actuator unit. The steering system is here defined in particular by the steering shaft of the steering system. This can advantageously reduce the load in the steering system.

[0013] Particularly preferably, the loads present in the servo system and the loads present in the steering system are compensated, wherein the total load corresponds particularly to the total rack force. This advantageously reduces the load on the entire steering system.

[0014] The actuator unit can be configured, for example, as an additional actuator, and is only configured to reduce the load on the steering system. Furthermore, particularly in the case of a steer-by-wire system, a feedback actuator can also be used as the actuator unit to provide a restoring torque to the steering lever. However, if an electric power steering actuator for providing steering torque is used as the actuator unit, a particularly simple and / or inexpensive construction can be achieved. In this context, "steering actuator" should be understood in particular as an actuator unit configured to provide steering torque and thereby advantageously influence the vehicle's direction of travel. Preferably, the steering actuator is configured to provide steering torque to support the driver's hand torque applied to the steering lever and / or to automatically and / or autonomously control the vehicle's direction of travel. The steering actuator can here be particularly arranged in the region of the steering system and particularly coupled to the steering shaft of the steering system. However, advantageously, the steering actuator is arranged in the region of the servo system and particularly coupled to the steering transmission of the steering system.

[0015] Furthermore, it is proposed that, in order to determine the load, particularly caused by external forces acting on the steering system, at least one operating parameter of the actuator unit and / or the movement of the steering lever of the steering system should be monitored and, in particular, evaluated. The operating parameter is preferably the acceleration of the actuator unit, particularly caused by external forces, and / or operating parameters related to acceleration, such as the operating voltage and / or operating current of the actuator unit. Furthermore, preferably, to monitor the movement of the steering lever, at least one motion sensor is used, specifically configured to detect motion signals related to the movement of the steering lever. Moreover, to determine the load, particularly caused by external forces acting on the steering system, at least one inertia and a favorable moment of inertia of the actuator unit and / or the steering lever and / or its peripheral components, particularly having dominant inertia, can be advantageously considered. This allows for particularly flexible and / or accurate determination of the load.

[0016] The methods for reducing the load on the steering system are not limited to the applications and implementations described above. In particular, the methods for reducing the load on the steering system may have a different number of individual elements, components, and units than those mentioned herein, in order to achieve the working manner described herein. Attached Figure Description

[0017] Other advantages will become apparent from the following description of the accompanying drawings. One embodiment of the invention is illustrated in the drawings.

[0018] Figure 1a -b illustrates an exemplary vehicle with a steering system in a simplified diagram, and

[0019] Figure 2 An exemplary flowchart showing the main method steps of a method for reducing the load on a steering system is shown. Detailed Implementation

[0020] Figure 1a and 1b The simplified illustration shows a vehicle 12, for example, a passenger vehicle constructed with multiple wheels 28 and a steering system 10. The steering system 10 is operatively connected to the wheels 28, which are currently configured as front wheels, and is configured to influence the travel direction of the vehicle 12. Furthermore, the steering system 10 is currently constructed as an electrically supported steering system and therefore has an auxiliary force support device in the form of servo steering. However, it is also conceivable in principle to construct the steering system as a hydraulically supported steering system, especially a steering system with a hydraulic auxiliary force support device. Furthermore, the steering system can also be constructed in principle as a steer-by-wire system.

[0021] The steering system 10 includes: a steering handle 22, configured as a steering wheel in the present case, for applying the driver's hand torque; a steering transmission 30, configured as a rack and pinion steering transmission, which includes a steering adjustment element 32 and is configured to convert the steering at the steering handle 22 into steering motion of the wheels 28; and a steering shaft 34 for mechanically connecting the steering handle 22 to the steering transmission 30. The steering transmission 30 defines a servo system 18 of the steering system 10. The steering shaft 34 defines a steering system 20 of the steering system 10. Alternatively, the steering handle may also be configured as a steering rod or a steering ball, etc. Furthermore, it is also possible to completely omit the steering handle. Additionally, the steering shaft may only temporarily connect the steering handle to the steering transmission and / or have a mechanical disconnect, as in a steering-by-wire system.

[0022] Furthermore, the steering system 10 includes an actuator unit 14. The actuator unit 14 is at least partially configured to be electric and / or electronic. In the present case, the actuator unit 14 is configured as a steering actuator. The actuator unit 14 is operatively connected to the steering transmission 30. The actuator unit 14 is coupled to the steering transmission 30, and particularly to the steering adjustment element 32. The actuator unit 14 is configured to provide steering torque to support the driver's hand torque applied to the steering handle 22 and transmitted to the steering adjustment element 32. For this purpose, the actuator unit 14 includes at least one electric motor. In the present case, the electric motor is particularly configured as a permanent magnet synchronous motor and configured to generate steering torque. However, in principle, the actuator unit may also include multiple electric motors. Furthermore, the actuator unit may also be configured as a feedback actuator, or as an additional actuator different from the steering actuator and the feedback actuator. Additionally, the actuator unit may also include multiple actuators, such as a steering actuator and a feedback actuator.

[0023] Furthermore, the steering system 10 includes at least one steering sensor 36, which is arranged on the steering shaft 34 and is known in itself. The steering sensor 36 is configured as a torque sensor. The steering sensor 36 is configured to detect steering information related to the operation of the steering handle 22, particularly the driver's hand torque and / or torque applied to the steering handle 22. In the present case, the steering sensor 36 is configured to detect a torsion bar signal. Alternatively, the steering sensor may also be configured as a sensor other than a torque sensor, such as a rotation angle sensor and / or a combination of torque and rotation angle sensors. Furthermore, the steering sensor may be omitted altogether.

[0024] The steering system 10 also includes at least one operating sensor 38 assigned to the actuator unit 14. The operating sensor 38 is configured as a rotor position sensor and is configured to detect at least one operating parameter of the actuator unit 14, in the present case, particularly the rotor position signal of the electric motor. However, alternatively or additionally, the operating sensor may also be configured as a sensor other than the rotor position sensor, such as an acceleration sensor, a solid-state noise sensor, a voltage sensor, a current sensor, and / or a temperature sensor. However, in principle, the operating sensor may also be omitted.

[0025] Furthermore, the steering system 10 includes at least one motion sensor 40. The motion sensor 40 is different from the steering sensor 36 and the running sensor 38. The motion sensor 40 is configured as a speed sensor. The motion sensor 40 is configured as a steering wheel sensor and is arranged in the area of ​​the steering handle 22. The motion sensor 40 is configured to detect motion signals related to the movement of the steering handle 22, particularly speed signals in the present case. However, alternatively, the motion sensor may also be configured as a sensor different from the speed sensor, such as a position sensor, distance sensor, acceleration sensor, and / or solid-state noise sensor, and is particularly configured to detect motion signals different from speed signals. Furthermore, the motion sensor may also, in principle, be arranged in the area of ​​the steering shaft, advantageously above the steering intermediate shaft. Alternatively, the motion sensor may be omitted entirely.

[0026] Furthermore, vehicle 12 has a controller 24. Controller 24 is configured, for example, as a steering controller, and is therefore part of steering system 10. Controller 24 has an electrical connection to actuator unit 14. Additionally, controller 24 is electrically connected to steering sensor 36, running sensor 38, and motion sensor 40. Controller 24 is configured to receive torsion bar signals from steering sensor 36, running parameters from running sensor 38, and motion signals from motion sensor 40. Furthermore, controller 24 is configured to operate actuator unit 14.

[0027] For this purpose, the controller 24 includes a computing unit 26. The computing unit 26 includes at least one processor (not shown), for example, a microprocessor, and at least one runtime memory (not shown). Furthermore, the computing unit 26 includes at least one runtime program stored in the runtime memory, the runtime program having at least one control routine, at least one calculation routine, at least one monitoring routine, and at least one evaluation routine. However, it is also conceivable in principle that the controller and steering system could be constructed separately. In this case, the vehicle could, for example, have a single central controller with a central computing unit.

[0028] Especially when driving on rough roads, very high loads are applied to the steering system 10, where the load depends on the magnitude and arrangement of the mass and inertia in the steering system 10, as well as the stiffness of the steering system 10 and, in particular, the stiffness of the servo system 18 and the steering system 20. The load is essentially caused by the steering system 10 being supported on the ground or road.

[0029] In order to reduce the load on the steering system 10, a corresponding method is proposed, wherein, in the present case, the computing unit 26 is configured to implement the method, and for this purpose, in particular, has a computer program with corresponding program code segments.

[0030] In the current situation, the load on the steering system 10 caused by the external forces acting on the steering system 10 is determined and compensated by manipulating the actuator unit 14 in at least one operating state. This load includes forces from the ground and / or the surrounding environment of the vehicle 12, and may be caused, for example, by unevenness of the road and / or by driving on rough roads.

[0031] To compensate for the load, the actuator unit 14 is manipulated during operation to reduce the inertial effect of the steering system 10 related to external forces. To this end, the actuator unit 14 generates a compensating torque to counteract the inertia of the steering system 10 and overcome the external forces, and applies it to the steering system 10, causing the steering system 10 to move together with the external forces, particularly in the direction of the external forces, and reducing the resistance of the steering system 10 to the external forces. In this situation, the effect of the inertia of the steering system 10 is thus minimized, thereby reducing the load at the corresponding critical locations of the steering system 10.

[0032] In order to control the actuator unit 14, the computing unit 26 has a load reduction function 16 for use in the operating state, which is stored in the operating memory of the computing unit 26. With the aid of the load reduction function 16, the actuator unit 14 is operated to generate a compensating torque. The load reduction function 16 is also specifically activated and deactivated according to driving conditions and particularly the current driving conditions. Under normal driving conditions with low load on the steering system 10, the load reduction function 16 is deactivated, so the driver does not perceive any change in steering behavior and / or steering feel. Under load conditions, such as when driving on rough roads, the load reduction function 16 is activated to reduce the load on the steering system 10. Therefore, the load reduction function 16 is advantageously not permanently activated and is only turned on when needed.

[0033] To activate and deactivate the load reduction function 16, load characteristic parameters related to the load caused by external forces acting on the steering system 10 and / or the current driving conditions are determined. These load characteristic parameters are determined continuously or monitored throughout the monitoring interval. Furthermore, the load reduction function 16 is activated when the load characteristic parameter exceeds a first limit value and deactivated when the load characteristic parameter falls below a second limit value different from the first limit value, thereby enabling corresponding hysteresis behavior.

[0034] Furthermore, the load reduction function 16, and in the current case, especially the compensation torque, can be manifested when activated and hidden when deactivated, thereby enabling activation and / or deactivation in a particularly inconspicuous manner. A ramp function is advantageously used for this purpose. However, alternatively, manifestation and / or hiding can also occur using functions other than the ramp function, such as asymptotic functions. Furthermore, manifestation and / or hiding can also be omitted.

[0035] In principle, the load consists of at least two main parts: the load in the steering transmission 30 and / or the servo system 18, and the load in the steering shaft 34 and / or the steering system 20.

[0036] According to the first embodiment, it is therefore conceivable to reduce only the load in the servo system 18. In this case, the actuator unit 14 is operated in the operating state such that the load present in the servo system 18 is compensated.

[0037] The load in servo system 18 can be determined using the following relationship:

[0038] (1)

[0039] Here, M S The description describes the total torque on the motor shaft of the electric motor in the actuator unit 14, which characterizes the load in the servo system 18. This total torque is composed of the component M from the first or generator. S,G That is, the acceleration of the servo system 18 and the component M of the second or motor. S,M That is, the motor torque acting on the motor shaft of the electric motor in actuator unit 14, and J S Characterizing the inertia of actuator unit 14, and ä S Characterizes the acceleration of actuator unit 14, particularly rotor acceleration.

[0040] In this case, to determine the load, especially the generator component M S,GThe load is of a certain form, therefore at least one operating parameter of the actuator unit 14, in particular the acceleration of the actuator unit 14, is monitored and evaluated in the current case. Furthermore, at least one inertia of the actuator unit 14 is considered in order to determine the load. Additionally, the motor component M... S,M The load in the servo system 18 can be determined using another operating parameter of the actuator unit 14, in particular the operating current and / or phase current of the motor in the current case. Furthermore, it is conceivable to consider at least one fundamental inertia of another steering component to determine the load.

[0041] For the compensation torque M κ1 In this case, the following applies:

[0042] (2)

[0043] However, alternatively, in principle, it is conceivable to compensate only for the component M caused by the generator by means of the actuator unit 14. S,G The resulting load or the component M of the motor S,M The resulting load can at least reduce the load in the steering system 10 and, in particular, the servo system 18.

[0044] According to the second embodiment, it is conceivable to reduce only the load in the steering system 20. In this case, the actuator unit 14 is operated in such a way that the load present in the steering system 20 is compensated.

[0045] The load in the steering system 20 can be determined using the following formula:

[0046] (3)

[0047] Here M L This describes the total torque in the region of the steering handle 22 that characterizes the load in the servo system 18, which is composed of another component M from the generator. L,G and driver's manual torque M L,F Composition, and J L Characterizing the inertia of the steering handle 22, and ä L Acceleration, particularly in the form of angular acceleration, characterizes the steering handle 22.

[0048] In this case, in order to determine the other component M, especially the generator L,GThe load is assessed by monitoring and evaluating at least one motion of the steering handle 22 detected by the motion sensor 40. For this purpose, the motion sensor 40 detects a motion signal related to the speed of motion of the steering handle 22, which is different from an acceleration signal, and then calculates the acceleration signal related to the motion of the steering handle 22 from this motion signal. The acceleration signal is advantageously calculated by taking the gradient and, in particular, using the difference quotient. However, alternatively, another type of differential calculation can be used, or the acceleration signal related to the motion of the steering handle can be directly detected. Furthermore, at least one inertia of the steering handle 22 is considered to determine the load. Additionally, the driver's hand torque M can be determined using the torsion bar signal from the steering sensor 36 and / or the motion signal from the motion sensor 40. L,F Furthermore, it is conceivable to consider at least one fundamental inertia of another steering component to determine the load in the steering system 20.

[0049] For the compensation torque M κ2 In this case, the following applies:

[0050] (4)

[0051] Here, i describes the transmission ratio of actuator unit 14, while η defines the corresponding efficiency.

[0052] However, alternatively, in principle, it is conceivable to compensate only for the other component M from the generator by means of the actuator unit 14. L,G The resulting load or the driver's manual torque M L,F The resulting load can at least reduce the load in the steering system 10 and, in particular, the steering system 20.

[0053] Furthermore, according to the third embodiment, it is conceivable to reduce the load in the servo system 18 and the load in the steering system 20. In this case, the actuator unit 14 is operated in the operating state such that the load present in the servo system 18 and the load present in the steering system 20 are compensated.

[0054] In this case, the total load (specifically corresponding to the total rack force) is obtained using the following relationship:

[0055] (5)

[0056] Here, M describes the total load, while i S and i L It is the corresponding transmission ratio in the servo system 18 and the steering system 20, while η S and η L This refers to the corresponding efficiency in the servo system 18 and the steering system 20.

[0057] For the total compensation torque M κ In this case, the following applies:

[0058] (6)

[0059] Here, i describes the transmission ratio of actuator unit 14, while η defines the corresponding efficiency.

[0060] at last, Figure 2 An exemplary flowchart showing the main method steps of a method for reducing the load in a steering system 10 is shown.

[0061] In method step 50, the load on the steering system 10 caused by external forces acting on it is determined. To this end, at least one operating parameter of the actuator unit 14 and / or the movement of the steering handle 22 are monitored and evaluated. This load may correspond to the load occurring in the servo system 18 and / or the load occurring in the steering system 20. Furthermore, load characteristic parameters related to the load caused by external forces acting on the steering system 10 and / or to the current driving condition are continuously determined and compared to a first limit value. If the load characteristic parameter exceeds the first limit value, method step 52 is executed.

[0062] In method step 52, the load reduction function 16 is activated, wherein preferably the load reduction function 16 is displayed.

[0063] In method step 54, when using the load reduction function 16, the actuator unit 14 is manipulated to generate a compensating torque that counteracts the inertia of the steering system 10 and overcomes the action of external forces. This compensating torque is applied to the steering system 10, causing it to move together with the external forces, particularly in the direction of the forces, and reducing the resistance of the steering system 10 to the external forces. This reduces the inertial effects of the steering system 10 related to the external forces and at least partially compensates for the load in the steering system 10. Furthermore, a load characteristic parameter is determined and compared to a second limit value. If the load characteristic parameter is lower than the second limit value, method step 56 is executed.

[0064] In method step 56, the load reduction function 16 is deactivated, wherein, preferably, the load reduction function 16 is hidden.

[0065] Figure 2 The exemplary flowchart herein is intended to describe, in particular, only as an example, a method for reducing the load in the steering system 10. In particular, the individual method steps may be changed, or additional method steps may be added.

Claims

1. A method for reducing load in a steering system (10), wherein, A load caused by an external force action acting on the steering system (10) is determined and at least partially compensated for in at least one operating state by means of actuating the actuator unit (14), and wherein in the operating state the actuator unit (14) is actuated in such a way that the inertia of the steering system caused by the external force action and / or the resistance of the steering system to the external force action is reduced, wherein the load caused by the external force action acting on the steering system (10) comprises force actions from the ground and / or the surroundings of the vehicle and is different from a steering movement and / or a direct force action on a steering wheel of the steering system.

2. The method of claim 1, wherein, In the operating state, by means of the actuator unit (14), a compensation torque and / or a compensation force counteracting the inertia of the steering system (10) is generated and applied to the steering system (10).

3. The method according to claim 1 or 2, characterized in that, In the operating state, for actuating the actuator unit (14), a load reduction function (16) is used, wherein the load reduction function (16) is activated and / or deactivated in particular in dependence on the driving situation.

4. The method of claim 3, wherein, A load characteristic variable related to the load is determined, wherein the load reduction function (16) is activated if the load characteristic variable exceeds a first limit value and deactivated if the load characteristic variable falls below a second limit value.

5. The method of claim 3, wherein, The load reduction function (16) is present when activated and / or hidden when deactivated.

6. The method according to claim 1 or 2, characterized in that, In the operating state, at least one load occurring in a servo system (18) is compensated for by actuating the actuator unit (14).

7. The method according to claim 1 or 2, characterized in that, In the operating state, at least one load occurring in a steering system (20) is compensated for by actuating the actuator unit (14).

8. The method of claim 1 or 2, wherein, An electric power steering actuator is used as the actuator unit (14) for providing a steering torque.

9. The method of claim 1 or 2, wherein, For determining the load, at least one operating variable of the actuator unit (14) and / or a movement of a steering wheel (22) is monitored.

10. The method of claim 1 or 2, wherein, The load comprises force actions from the ground and / or the surroundings of the vehicle (12).

11. The method of claim 1, wherein, The method is used for reducing a load in the steering system (10) during operation in a vehicle (12).

12. A controller (24) having a computing unit (26) for carrying out the method according to any one of claims 1 to 11.

13. The controller (24) of claim 12, characterized by The controller (24) is a steering controller.

14. A vehicle (12) having a steering system (10) comprising at least one actuator unit (14) and a computing unit (26) for carrying out the method according to any one of claims 1 to 11.

15. The vehicle (12) of claim 14, characterized by The vehicle (12) is a motor vehicle.

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