阅读说明：本技术 用于运行用来操控电气转向装置的转向控制装置的方法和转向控制装置 (Method for operating a steering control device for actuating an electric steering device and steering control device ) 是由 J·格朗巴赫 N·斯皮思 M·福克斯 T·尼罗比施 M·里格尔 S·斯特劳布 S·塞尔扎 于 2019-12-07 设计创作，主要内容包括：本发明涉及一种用于运行用来操控电气转向装置(12)的转向控制装置(10)的方法,其中,在至少一种故障运行状态中,通过次级计算单元(16)代替初级计算单元(14)并且借助次级计算单元(16)按照调节的方式操控电气转向装置(12)的转向致动机构(18),在该故障运行状态中出现初级计算单元(14)的干扰和/或失效,并且其中,在至少一种正常运行状态中,借助次级计算单元(16)至少暂时按照调节的方式操控模拟单元(20),在该正常运行状态中尤其是初级计算单元(14)被设置用于操控转向致动机构(18),所述模拟单元至少部分地模拟和/或模仿转向致动机构(18)。(The invention relates to a method for operating a steering control device (10) for actuating an electric steering device (12), wherein, in at least one fault operating state, the primary computing unit (14) is replaced by the secondary computing unit (16) and the steering actuating mechanism (18) of the electric steering device (12) is actuated in a regulated manner by means of the secondary computing unit (16), in the fault operating state, a disturbance and/or a failure of the primary computing unit (14) occurs, and wherein, in at least one normal operating state, the simulation unit (20) is actuated at least temporarily in a regulated manner by means of the secondary computing unit (16), in the normal operating state, in particular the primary computing unit (14) is provided for actuating the steering actuator (18), the simulation unit at least partially simulates and/or imitates a steering actuation mechanism (18).)

1. A method for operating a steering control device (10) for actuating an electric steering device (12), wherein, in at least one fault operating state, the primary computing unit (14) is replaced by the secondary computing unit (16) and the steering actuating mechanism (18) of the electric steering device (12) is actuated in a regulated manner by means of the secondary computing unit (16), in the fault operating state, a disturbance and/or a failure of the primary computing unit (14) occurs, and wherein, in at least one normal operating state, the simulation unit (20) is actuated at least temporarily in a regulated manner by means of the secondary computing unit (16), in the normal operating state, in particular the primary computing unit (14), is provided for actuating the steering actuator (18), the simulation unit at least partially simulates and/or imitates a steering actuation mechanism (18).

2. The method according to claim 1, characterized in that the secondary computing unit (16) is kept in a hot standby mode in a normal operating state by actuating the simulation unit (20), in particular such that a direct transition from the primary computing unit (14) to the secondary computing unit (16) can be achieved in a fault operating state.

3. Method according to claim 1 or 2, characterized in that in the normal operating state, the actuation of the simulation unit (20) by the secondary computing unit (16) is carried out in parallel and/or synchronously with the actuation of the steering actuator (18) by the primary computing unit (14).

4. Method according to one of the preceding claims, characterized in that in at least one operating state at least one secondary control variable associated with the secondary computing unit (16) and/or the simulation unit (20) is used for plausibility checking, for checking and/or for at least temporarily replacing at least one primary control variable associated with the primary computing unit (14) and/or the steering actuator (18).

5. Method according to any one of the preceding claims, characterized in that the simulation unit (20) comprises at least one, in particular linearized, steering model for simulating and/or mimicking the steering actuation mechanism (18).

6. Method according to one of the preceding claims, characterized in that the steering actuator (18) is actuated in a controlled manner at least temporarily, in particular at least in a transition phase from a normal operating state to a fault operating state, wherein for the control at least one, in particular linearized, further steering model is used.

7. The method according to one of the preceding claims, characterized in that the secondary computing unit (16) is integrated into a secondary controller (24) and the primary computing unit (14) is integrated into a primary controller (22) which is constructed separately from the secondary controller (24).

8. The method according to any one of the preceding claims, characterized in that the secondary calculation unit (16) and the simulation unit (20) are integrated into a common controller (24).

9. Steering control device (10), in particular a steering control device (10) for use in a method according to one of claims 1 to 8, having at least one secondary computing unit (16) which is provided for controlling a steering actuating mechanism (18) of an electric steering device (12) in an adjusted manner in place of the primary computing unit (14) in at least one faulty operating state in which a disturbance and/or a failure of the primary computing unit (14) occurs, and having at least one simulation unit (20) which at least partially simulates and/or imitates the steering actuating mechanism (18), wherein the secondary computing unit (16) is provided for controlling the simulation unit (20) in an adjusted manner at least temporarily in at least one normal operating state, in the normal operating state, in particular the primary computing unit (14) is provided for actuating the steering actuator (18).

10. Steering system (26) with at least one steering control device (10) according to claim 9 and at least one electric steering device (12).

11. Vehicle (28) having a steering system (26) according to claim 10, wherein the vehicle (28) comprises at least one autonomous, in particular highly automated, driving mode.

Technical Field

The invention relates to a method for operating a steering control device for actuating an electric steering device and to a steering control device. The invention further relates to a steering system having such a steering control device and to a vehicle having such a steering system.

Background

Conventional steering systems with hydraulic steering assistance or electric steering assistance in the form of power steering are known from the prior art, wherein an electric motor is used to generate the steering assistance in at least the latter case. As a safety measure, for example, in the event of a failure of an electrical and/or electronic component of the steering system, a mechanical back-up level (ruckfillebene) can be used, which is provided to enable steering even in the event of failure of the steering assistance and to ensure a controlled and safe operation. However, suddenly switching off the steering assist results in a large moment jump on the steering wheel of the steering system, which can be very annoying to the driver and increase the risk of accidents. Against this background, it is proposed, for example, in DE 102010050820 a1 that, in the event of a failure of the primary computing unit, the operation of the steering system is controlled by means of a secondary computing unit in the form of a monitoring computer, as a result of which at least abrupt changes in the torque on the steering wheel can be reduced.

With increasing automation in the vehicle sector and in particular in the steering sector, such as for example in highly automated driving, fully redundant or fail-safe systems are furthermore required, which can also continue to guide and/or maintain the intended functionality even in the event of a first failure. For this purpose, a plurality of computing units are usually used, wherein the primary computing unit controls the normal operating state and is replaced by a secondary computing unit in the fault operating state, in which a disturbance and/or a failure of the primary computing unit occurs. Such fault-tolerant systems are disclosed, for example, in DE 102015003194 a1 and/or DE 112015001283T 5.

However, in particular in the case of regulated systems, the problem is that with the system mentioned at the outset, the availability of the secondary computing unit or backup level at the time of a fault cannot be ensured, since the secondary computing unit is not connected to the closed primary control loop and therefore remains in a fixed operating point during normal operation. Thus, a so-called "potential fault" cannot be reliably detected at least over the entire operating range of the secondary computing unit, as a result of which a safety-critical operating state can be generated.

Disclosure of Invention

The object of the invention is, in particular, to provide a method and a steering control device having improved properties with regard to operational safety. This object is achieved by the features of claims 1, 9, 10 and 11, while advantageous embodiments and refinements of the invention are apparent from the dependent claims.

A method for operating a steering control device for actuating an electric steering device is proposed, wherein a steering actuating mechanism of the electric steering device is actuated in an adjusted manner by a secondary computing unit instead of a primary computing unit in at least one faulty operating state in which a disturbance and/or a failure of the primary computing unit occurs, and wherein a simulation unit is actuated at least temporarily in an adjusted manner by the secondary computing unit in at least one normal operating state in which, in particular, the primary computing unit is provided for actuating the steering actuating mechanism, which simulation unit at least partially simulates and/or simulates (nachblden) the steering actuating mechanism, advantageously in order to hold the secondary computing unit in a standby mode and/or in order to check and/or monitor, in particular over the entire operating range, the functional capability of the secondary computing unit Force. In particular, the primary computing unit is provided for actuating the steering actuator in an adjusted manner in the normal operating state, while the secondary computing unit is provided in particular for not actuating the steering actuator in the normal operating state. Preferably, the secondary computing unit is provided only for operating the simulation unit in the normal operating state. In particular, it is advantageous if the primary computing unit and the steering actuator form, in particular, a closed, real and/or primary control loop in the normal operating state, while the secondary computing unit and the simulation unit form, in particular, a closed, virtual and/or secondary control loop in the normal operating state. In the fault operating state, the primary computing unit is replaced by the secondary computing unit, in particular in such a way that the secondary computing unit is connected to, in particular, a closed, real and/or primary control loop, and thus the secondary computing unit and the steering actuator form, in particular, a closed, real control loop in the fault operating state. The secondary computing unit thus advantageously forms a redundant backup level, which has an increased availability, in particular compared to solutions known from the prior art. In particular, in the case where the secondary computing unit is provided for actuating the simulation unit in the normal operating state in such a way that the operating point and/or the operating range of the secondary computing unit is at least similar and/or advantageously identical to the primary computing unit, an advantageously frictionless transition from the primary computing unit to the secondary computing unit is achieved in the fault operating state. This embodiment therefore makes it possible in particular to increase the operational safety and to provide a so-called fail-safe system which is also available in the fail operating state. In addition, the secondary computing unit can intervene, in particular at least virtually, so that the secondary computing unit can be advantageously monitored during ongoing operation in terms of what is known as a "latent fault", preferably over the entire operating range of the secondary computing unit.

A "steering control device" is to be understood in this context to mean, in particular, at least one part of the steering system, in particular a subassembly thereof, which is provided, in particular in at least one operating state, for actuating the electric steering device and, in particular, a steering actuating mechanism of the electric steering device. The steering control device comprises, in particular, a secondary computing unit and a simulation unit for this purpose. Further, the steering control device may further include a primary calculation unit. Furthermore, an "electric steering device" is to be understood to mean, in particular, at least one further part of the steering system, in particular a further subassembly, which is provided, in particular, at least for directly influencing the driving direction of the vehicle. For this purpose, the electric steering device comprises in particular a steering actuator which can have in particular a wheel steering angle adjuster, for example in the form of a steering gear, an output stage and/or a servomotor. Furthermore, the electric steering device can also comprise a steering sensor, in particular operatively connected to the steering actuator, such as, for example, at least one steering sensor, at least one rotor sensor, in particular assigned to a servomotor, at least one rack position sensor, in particular assigned to a wheel steering angle adjuster, and/or at least one rack speed sensor, in particular assigned to a wheel steering angle adjuster. The steering control device and the electric steering device are therefore in particular part of a steering system which is in particular provided for use in a vehicle and preferably in a motor vehicle. Preferably, the vehicle comprises at least one autonomous and particularly advantageously highly automated driving mode. Furthermore, the normal operating state preferably corresponds to normal operation during the autonomous and/or highly automated driving mode, and the fault operating state corresponds to fault operation during the autonomous and/or highly automated driving mode. "provided" is to be understood in particular to mean specially programmed, designed and/or equipped. The expression "an object is provided for a specific function" is intended to mean, in particular, that the object fulfills and/or performs this specific function in at least one operating state and/or operating state.

Furthermore, a "computer unit" is to be understood to mean, in particular, an electrical and/or electronic unit, advantageously a regulator unit, which has an information input, an information processing unit and an information output. Advantageously, the computing unit, in particular the primary computing unit and/or the secondary computing unit, also has at least one processor, for example in the form of a microprocessor, at least one operating memory, at least one input and/or output device, at least one operating program, at least one control routine, at least one regulating routine, at least one computing routine and/or at least one processing routine. In addition, the secondary computing unit advantageously has an operative connection with the primary computing unit and/or the steering actuator and is provided in particular for replacing the primary computing unit and taking over the control of the steering actuator in the fault operating state. In a normal operating state and in a fault operating state, the primary computing unit is advantageously provided for using the same and/or the same, in particular existing, components and connecting lines and preferably operating the same output stage and/or the same servomotor for actuating the steering actuator. The primary and secondary computation units can be designed in particular as diverse as one another or identical to one another. Furthermore, the primary computing unit comprises, in particular, a high-level software for actuating the steering actuators, which is advantageously suitable for carrying out autonomous and advantageously highly automated driving processes. Particularly advantageously, the secondary computing unit comprises a further high-level software for actuating the steering actuation mechanism, which is advantageously suitable for carrying out autonomous and advantageously highly automated driving processes. Furthermore, the primary and/or secondary computing unit is advantageously integrated into the control unit of the steering control device.

Furthermore, the term "disturbance and/or failure of the primary computing unit" is to be understood in particular to mean disturbance and/or failure of the primary computing unit itself and/or of peripheral components (such as, for example, energy supply devices) interacting with the primary computing unit, as well as any resultant disturbance of the primary computing unit. Furthermore, an "analog unit" is to be understood to mean, in particular, an electrical and/or electronic unit, which is provided, in particular, for simulating and/or imitating at least a part and advantageously at least a majority of the physical properties of, in particular, a real steering actuation mechanism. Furthermore, the simulation unit can also be provided for simulating and/or imitating axle forces, which can occur in particular at axles that can be steered advantageously. For this purpose, the simulation unit comprises in particular at least one information input, at least one information output, at least one further operating memory and/or advantageously at least one memory section in the operating memory of the primary and/or of the secondary computing unit. Furthermore, the simulation unit for simulating or simulating the steering actuation mechanism and advantageously the shaft forces may also comprise at least one further processor.

The secondary computing unit can be provided in particular for actuating the simulation unit in a regulated manner only temporarily and/or at regular time intervals in the normal operating state, such as, for example, at system start-up. In this context, it is conceivable, for example, to operate the secondary computing unit for a short time for a self-test and/or for checking the functional capability of the secondary computing unit and to check the entire operating range of the secondary computing unit, for example by means of a signal ramp, as a result of which, in particular, an advantageous checking of the secondary computing unit is achieved and, at the same time, a high energy efficiency, in particular compared to continuous operation, can be achieved. However, it is advantageously provided that the secondary computing unit is kept in the hot standby mode in the normal operating state by, in particular, permanently actuating the analog unit, in particular so that a direct transition from the primary computing unit to the secondary computing unit is made and/or enabled in the fault operating state. The expression "hot standby mode" is to be understood in this context to mean, in particular, a mode in which the secondary computing unit remains in a standby mode and/or a standby mode, which is active and advantageously energy-saving, and is thus available, in particular, immediately. In particular, this ensures a particularly high availability of the secondary computing unit, so that in the event of a faulty operating state, an advantageously uninterrupted transition from the primary computing unit to the secondary computing unit can be achieved. In this case, the secondary computing unit used as a backup level can advantageously also be kept active without intervention (Durchgriff) on the real system, in particular in the form of a steering actuator, in order to be able to switch directly to a redundant replacement system or secondary computing unit in the event of a faulty operating state. Such a method is provided in particular in safety-critical operating states, such as, for example, autonomous and in particular highly automated driving.

Furthermore, it is proposed that, in the normal operating state, the actuation of the analog unit by the secondary computing unit is carried out in parallel and/or synchronously with the actuation of the steering actuation mechanism by the primary computing unit. In particular, the secondary computing unit is provided in this case for actuating the simulation unit in the normal operating state in such a way that the operating point and/or the operating range of the secondary computing unit is at least similar to and/or advantageously identical to the primary computing unit. Furthermore, it is advantageous if the secondary prevailing variable of the secondary control loop and/or the secondary prevailing variable assigned to and/or supplied to the secondary computing unit is identical to the primary prevailing variable of the primary control loop and/or the primary prevailing variable assigned to and/or supplied to the primary computing unit. In this case, the primary and/or secondary prevailing variable is particularly preferably assigned to a target rack position and/or a target rack speed. In particular, this enables a particularly effective and/or rapid transition to the fault operating state. Furthermore, a synchronization of, for example, the system state between the primary computing unit and the secondary computing unit can advantageously be dispensed with, as a result of which the duration of the transition phase from the normal operating state to the fault operating state can advantageously be significantly reduced.

In addition, it is proposed that, in at least one operating state, at least one secondary control variable associated with the secondary computing unit and/or the simulation unit is used for plausibility checking, for checking and/or for at least temporarily replacing at least one primary control variable associated with the primary computing unit and/or the steering actuator and in particular corresponding to the secondary control variable. In particular, therefore, the primary control characteristic is assigned to the primary control loop, and the secondary control characteristic is assigned to the secondary control loop. A "control characteristic" is to be understood in this context to mean, in particular, a characteristic which is associated with a control operation of the respective control loop. The control characteristic variable may correspond, for example, to a control deviation, a servo variable, a control variable and/or a feedback variable of the respective control loop. In particular, this makes it possible to achieve an advantageously high level of operational safety and/or an increase in the robustness of the system, in particular to monitor the actual and/or primary control loop and/or to compensate for at least short-term faults in the primary control loop, such as, for example, temporary unavailability of the respective prevailing variable, in particular without having to switch directly to the secondary computing unit and the emergency operating device connected thereto.

The simulation unit may comprise, for example, a further processor in the form of a microprocessor and/or a neural processor for, for example, repeatedly and/or continuously simulating and/or mimicking the steering actuation mechanism, in particular by means of a transfer function. However, according to a particularly preferred embodiment, it is provided that the simulation unit comprises at least one, in particular previously applied, steering model for simulating and/or simulating a steering actuator. The steering model can be acquired in particular by means of test measurements and/or by means of special algorithms and stored in particular in a further operating memory of the simulation unit. Furthermore, the steering model can in particular correspond to a physical model of the steering actuator, which imitates the actual steering as accurately as possible. Advantageously, however, the steering model corresponds to a simplified and particularly preferably linearized model of the steering actuator. This makes it possible in particular to reduce the computational effort and at the same time to achieve a particularly high energy efficiency.

Furthermore, it is proposed that the steering actuator be actuated in a controlled manner at least temporarily and advantageously at least in a transition phase from a normal operating state to a fault operating state, wherein at least one, in particular linearized and in particular inverted (inverted), further steering model is used for the control and/or for the pilot control, which further steering model in particular at least partially simulates and/or imitates the steering actuator. Preferably, the further steering model is identical to the steering model already mentioned above. In this case, the control and/or the pre-control can be implemented in particular by means of a primary computing unit, a secondary computing unit and/or a further computing unit of the steering control device. In particular, this can simplify the control algorithm and/or further reduce the computational complexity. In particular in less critical driving situations, such as, for example, in motorway driving, the actuation of the steering actuator by the pilot control may be sufficient to set the desired rack position, for example. In addition, in the event of a fault in the primary control circuit, the control and/or pilot control can advantageously take over the actuation of the steering actuator at least for a short time, as a result of which a particularly high level of safety can be achieved, in particular during the transition phase from the normal operating state to the fault operating state.

The primary and secondary computation units may be integrated in particular into the same controller, for example in the form of a multicore processor and/or in the form of separate processors. However, when the secondary computing unit is integrated into the secondary controller and the primary computing unit is integrated into a primary controller which is configured separately from the secondary controller, an advantageous increase in redundancy, in particular with regard to autonomous and advantageously highly automated driving, can be achieved in particular.

Furthermore, it is preferably provided that the secondary computation unit and the simulation unit are integrated into a common controller, in particular the secondary controller already mentioned above, as a result of which, in particular, faults due to line interruptions or the like can be minimized and the operational safety can be further increased.

Furthermore, a steering control device, in particular for use in the above-described method, is proposed, which has at least one secondary computing unit, which is provided to replace the primary computing unit and to actuate a steering actuator of the electric steering device in an adjusting manner in at least one error operating state in which a disturbance and/or a failure of the primary computing unit occurs, and which has at least one simulation unit, which at least partially simulates and/or imitates the steering actuator, wherein the secondary computing unit is provided to actuate the simulation unit in an adjusting manner at least temporarily in at least one normal operating state in which in particular the primary computing unit is provided to actuate the steering actuator, advantageously, the secondary computing unit is kept in a standby mode and/or the functional capability of the secondary computing unit is checked and/or monitored, in particular over the entire operating range. The advantages already mentioned above can be achieved in particular thereby. In particular, the operational safety can be increased and a so-called fail-safe system is provided, which is also available in the fail operational state. In addition, the secondary computing unit can intervene, in particular at least virtually, so that the secondary computing unit can be advantageously monitored during ongoing operation in terms of what is known as a "latent fault", preferably over the entire operating range of the secondary computing unit.

The method for operating the steering control device and the steering control device should not be limited to the above-described applications and embodiments. In particular, the method for operating the steering control device and the steering control device may have a different number of individual elements, components and units than those described here in order to satisfy the operating principle described here.

Drawings

Other advantages are given by the following description of the figures. An embodiment of the invention is shown in the drawings. The figures, description and claims contain aspects of the present invention. The person skilled in the art can also appropriately consider these aspects separately and conclude other combinations of significance. In which is shown:

fig. 1 shows, in a simplified representation, a vehicle with a steering system, which comprises a steering control and an electric steering,

fig. 2 shows a schematic representation of the primary and secondary control units of the steering control device and of the steering actuating mechanism of the electric steering device, wherein the actuation behavior of the steering control device in the normal operating state and the actuation behavior of the steering control device in the fault operating state are shown,

figures 3a-b show simplified diagrams of the operating characteristics of the primary computing unit of the primary controller and of the secondary computing unit of the secondary controller in a normal operating state,

FIG. 4 shows a simplified diagram of the operating behavior of the secondary computing unit in the fault operating state, and

fig. 5 shows an exemplary flowchart with the main method steps of a method for operating a steering control device.

Detailed Description

Fig. 1 shows a vehicle 28, which is designed as a passenger car in a simplified illustration and has a plurality of wheels (not shown) and a steering system 26. The vehicle 28 here comprises, by way of example, at least one autonomous, in the present case in particular highly automated driving mode (at least SAE level 3). In principle, however, it is also conceivable that the vehicle may only comprise a conventional and/or manual driving mode and/or a partially autonomous driving mode.

The steering system 26 includes an electric steering apparatus 12. The electric steering device 12 has an operative connection with the wheels and is provided for influencing the direction of travel of the vehicle 28. For this purpose, the electric steering device 12 comprises a particularly real and/or physical steering actuation mechanism 18 (see fig. 2). The steering actuator 18 is designed as an actuator known per se and can comprise, for example, a wheel steering angle adjuster, in particular designed as a steering gear, an output stage and/or a servomotor, in particular for providing electric steering assistance. Further, the electric steering device 12 may include a steering sensing mechanism 30. The steering sensing mechanism 30 is configured as a known per se sensing mechanism. The steering sensing element 30 is provided to provide at least one steering characteristic 32. To this end, the steering sensing mechanism 30 may include, for example, at least one steering sensor, at least one rotor sensor, at least one rack position sensor, and/or at least one rack speed sensor. Furthermore, the electric steering device 12 can in principle be designed as a conventional steering device with mechanical intervention or also as a steer-by-wire device. In principle, the electric steering system can also be designed as an at least partially electrically designed hydraulic steering system or as a hydraulically assisted steering system. In this case, the servomotor can also be omitted. Furthermore, the steering characteristic variable can also be called up from a bus system or the like, so that in particular the corresponding steering sensor can also be dispensed with.

Further, the steering system 26 includes the steering control device 10. The steering control device 10 is provided for actuating the electric steering device 12 and in particular for actuating a steering actuating mechanism 18 of the electric steering device 12. To this end, the steering control device 10 comprises at least one primary control unit 22 (see in particular fig. 2). Alternatively, the steering control device can also be designed as a central control device of the vehicle and thus in particular differs from the steering system.

The primary controller 22 has operative connections with the steering sensing mechanism 30 and the steering actuation mechanism 18. The primary controller 22 is configured as a master controller. At least, primary controller 22 is provided to actuate steering actuator 18 as a function of steering characteristic 32 in normal operating states, in particular in the normal operating states of an autonomous and/or highly automated driving mode.

To this end, the primary controller 22 includes at least one primary computing unit 14. The primary computing unit 14 comprises at least one primary processor (not shown) for example in the form of a microprocessor and at least one primary operating memory (not shown). In addition, the primary computing unit 14 includes at least one primary operating software stored in a primary operating memory and associated with a normal operating state. The primary operating software includes a primary operating program having a tuning routine. The primary operating software corresponds in the present case to a high-level software which is suitable for carrying out autonomous and/or highly automated driving processes. Alternatively, however, the primary operating software may also be adapted only to carry out conventional and/or partially autonomous driving processes.

The primary computing unit 14 is provided for actuating the steering actuator 18 in an adjusted manner in the normal operating state. For this purpose, the primary computing unit 14 and the steering actuator 18 form, in particular, a closed, real and/or primary control loop in the normal operating state. The steering characteristic 32, in the present case in particular the target rack position and/or the target rack speed, forms a primary prevailing variable 34 of the primary control loop. The primary regulation loop is again shown in fig. 3 a.

Furthermore, the primary controller 22 comprises at least one further calculation unit 36. The further calculation unit 36 comprises at least one further processor (not shown), for example in the form of a microprocessor, and at least one further operating memory (not shown). Furthermore, the further computing unit 36 comprises at least one further operating software stored in a further operating memory. The further operating software comprises a further operating program with a control routine.

The further computing unit 36 is provided for actuating the steering actuator 18, in particular in addition to the primary computing unit 14 and/or instead of the primary computing unit 14, at least temporarily in a controlled manner. The further computing unit 36 is provided in the present case for implementing a pre-control. For this purpose, a steering model, in particular a reverse steering model, which at least partially simulates and/or simulates at least the steering actuator 18 and the shaft forces which advantageously occur during operation, is stored in the further operating memory. The steering model advantageously corresponds to a simplified and/or linearized model of the steering actuator 18. But alternatively such a further calculation unit may be dispensed with. In this case, for example, it is conceivable to implement the regulation and the pre-control by means of the same computing unit and/or the same processor. Furthermore, it is conceivable to carry out the pre-control by means of a physical steering model and/or a specific algorithm. Furthermore, the preliminary control may be omitted entirely.

Since the steering system 26 is a safety-relevant vehicle component which has a direct influence on the guidance of the vehicle, a corresponding safety measure is required in the event of a faulty operating state in which disturbances and/or failures of the primary computing unit 14 itself and/or of peripheral components (e.g. energy supply devices) interacting with the primary computing unit 14 and the resulting disturbances of the primary computing unit 14 occur.

For this reason, the steering control device 10 comprises in the present case at least one secondary control 24 (see in particular fig. 2). Alternatively, however, the steering control can also comprise exactly one control unit or at least three control units. The secondary controller 24 is configured separately from the primary controller 22. The secondary controller 24 is configured redundantly with respect to the primary controller 22. The secondary controller 24 has operative connections with the steering sensing mechanism 30 and the steering actuation mechanism 18. The secondary controller 24 is configured as a secondary controller and/or a backup controller. The secondary controller 24 is provided for actuating the steering actuator 18 as a function of the steering characteristic variable 32 in at least one fault operating state, in particular in a fault operating state of the autonomous and/or highly automated driving mode, in which a disturbance and/or a failure of the primary controller 22 and in particular of the primary computing unit 14 occurs.

To this end, the secondary controller 24 comprises at least one secondary computing unit 16. The secondary computing unit 16 comprises at least one secondary processor (not shown), for example in the form of a microprocessor, and at least one secondary operating memory (not shown). In addition, the secondary computing unit 16 includes at least one secondary operating software stored in a secondary operating memory and associated with a faulty operating state. The secondary operating software includes a secondary operating program having a tuning routine. The secondary operating software also corresponds in the present case to a high-level software which is suitable for carrying out autonomous and/or highly automated driving processes. Alternatively, however, the secondary operating software may also be adapted only to carry out conventional and/or partially autonomous driving processes and/or to provide emergency operation, for example in order to reduce sudden changes in torque at the steering handle.

The secondary computing unit 16 is provided to replace the primary computing unit 14 and to take over the control of the steering actuator 18 in a fault operating state, in which in particular a disturbance and/or a failure of the primary computing unit 14 occurs. The secondary computing unit 16 is provided here for actuating the steering actuator 18 in an adjusting manner. For this purpose, the secondary computing unit 16 is switched into the, in particular, closed, actual and/or primary control circuit in the fault operating state, so that the secondary computing unit 16 and the steering actuator 18 form, in particular, a closed, actual control circuit in the fault operating state. The steering characteristic 32 in this case again forms the main variable for the actual control loop in the fault operating state. Fig. 2 shows the actuation of the steering actuator 18 in the fault operating state by means of a dashed line. Fig. 4 again shows the actual control loop in the fault operating state. In principle, it is of course also conceivable to use the deviation parameter prevailing in the fault operating state. Furthermore, the primary and secondary computation units may in particular also be integrated into the same controller, for example in the form of a multi-core processor and/or in the form of two separate processors. In addition, the steering control device may also comprise, in particular, at least one further secondary computing unit, which replaces the secondary computing unit in at least one further fault operating state in which a disturbance and/or a failure of the primary computing unit and of the secondary computing unit occurs, and is provided for actuating the steering actuating mechanism in an adjusting manner.

In order to increase the availability of the secondary computing unit 16 or of the backup level and to prevent safety-critical operating states, in particular in the event of sudden disturbances and/or sudden failures of the primary computing unit 14, the steering control device 10 comprises a simulation unit 20. The analog unit 20 is in the present case integrated into the secondary controller 24. The simulation unit 20 is provided for at least partially simulating and/or imitating a particularly real steering actuator 18. For this purpose, the simulation unit 20 comprises a further steering model, which is applied in particular beforehand. The further steering model is identical to the steering model of the further computation unit 36 and therefore corresponds to a simplified and/or linearized model of the steering actuator 18. In addition, the further steering model is stored in the secondary operating memory and/or in a further operating memory of the simulation unit 20. Alternatively, the simulation unit can of course also be integrated into the primary controller and/or the central controller of the vehicle. Furthermore, it is conceivable to use a physical steering model and/or special algorithms to simulate and/or simulate the steering actuators.

In order to keep the secondary computing unit 16 in the standby mode even in the normal operating state, in which in particular the primary computing unit 14 is provided for actuating the steering actuator 18, the secondary computing unit 16 is provided for actuating the simulation unit 20 in an at least temporarily regulated manner in the normal operating state. For this purpose, the secondary computing unit 16 and the simulation unit 20 form, in the normal operating state, in particular a closed virtual and/or secondary control loop. The steering characteristic 32, in the present case in particular the target rack position and/or the target rack speed, forms a secondary prevailing variable 38 of the secondary control loop. The secondary prevailing variable 38 is therefore identical to the primary prevailing variable 34. In principle, however, it is also conceivable to use different prevailing variables for the primary and secondary control circuits in the normal operating state. The secondary regulation loop is again shown in fig. 3 b.

Furthermore, the secondary computing unit 16 is kept in the so-called "hot standby mode" in the normal operating state by, in particular, permanently activating the analog unit 20, so that a direct transition from the primary computing unit 14 to the secondary computing unit 16 can be achieved in the fault operating state. In this case, the actuation of the simulation unit 20 by the secondary computing unit 16 is carried out in parallel and/or synchronously with the actuation of the steering actuator 18 by the primary computing unit 14, more particularly in such a way that the operating point and/or the operating range of the secondary computing unit 16 is at least similar to and preferably identical to that of the primary computing unit 14. With this configuration, the secondary computing unit 16 used as a backup level can also be kept active without intervention in the actual system, in particular in the form of a steering actuator 18, in order to be able to switch directly to a redundant replacement system or secondary computing unit 16 in the event of a faulty operating state. Furthermore, the transition phase from the normal operating state to the fault operating state can be significantly reduced, since a synchronization between the primary computing unit 14 and the secondary computing unit 16, for example a synchronization of the system state, can be dispensed with. Alternatively, the secondary computing unit can also be provided to actuate the simulation unit in a regulated manner only temporarily and/or at regular time intervals in the normal operating state. In this context, it is conceivable, for example, to operate the secondary computing unit for a short time for a self-test and/or for checking the functional capability of the secondary computing unit and to check the entire operating range of the secondary computing unit, for example, by means of a signal ramp.

Furthermore, it can be provided that the further computing unit 36 is provided for actuating the steering actuator 18 in a controlled manner in the transition phase from the normal operating state to the fault operating state, so that the actuation of the steering actuator 18 can be at least temporarily undertaken by means of the pilot control and a particularly high level of safety can be achieved in particular during the transition phase from the normal operating state to the fault operating state. In principle, however, such a control and/or pre-control can also be omitted during the transition phase.

Furthermore, it can be provided that, in at least one operating state, at least one secondary control characteristic variable associated with the secondary computing unit 16 and/or the simulation unit 20, such as, for example, a secondary pilot variable 38, a secondary control deviation, a secondary servo variable, a secondary control variable and/or a secondary feedback variable of the secondary control loop, is used for plausibility checking, for checking and/or for at least temporarily replacing at least one primary control characteristic variable associated with the primary computing unit 14 and/or the steering actuator 18 and corresponding to the secondary control characteristic variable, such as, for example, a primary pilot variable 34, a primary control deviation, a primary servo variable, a primary control variable and/or a primary feedback variable of the primary control loop, whereby, in particular, the robustness of the system can be increased and at least short-term malfunctions in the primary control loop can be compensated for, such as, for example, a temporary unavailability of the primary dominant variable 34, without in particular having to switch directly to the secondary computing unit 16.

Finally, fig. 5 shows an exemplary flowchart with the main method steps of a method for operating the steering control device 10.

Method step 50 corresponds to a normal operating state (see also fig. 3a and 3 b). In this case, the steering actuator 18 is actuated in an actuating manner by means of the primary computing unit 14. Furthermore, the analog unit 20 is controlled by the secondary computing unit 16 in an adjusted manner, as a result of which the secondary computing unit 16 is kept in the hot standby mode.

In method step 52, a disturbance and/or a failure of primary computing unit 14 occurs, thereby initiating a particularly manual or advantageously automatic transition from the normal operating state into the fault operating state. By keeping the secondary computing unit 16 active in the normal operating state, a direct transition from the primary computing unit 14 to the secondary computing unit 16 can be achieved, whereby the duration of the transition phase from the normal operating state to the fault operating state can be significantly reduced.

Method step 54 corresponds to a fault operating state (see also fig. 4). In this case, the primary computing unit 14 is replaced by the secondary computing unit 16, in particular such that the secondary computing unit 16 is switched into a closed, real and/or primary control loop. In a fault operating state, the steering actuator 18 is therefore actuated in an adjusted manner by means of the secondary computing unit 16.

In particular, the exemplary flowchart in fig. 5 is intended to describe merely an exemplary method for operating the steering control device 10. In particular, the individual method steps can also be varied. Furthermore, optional method steps can be added, such as, for example, in the transition phase from the normal operating state to the fault operating state, such as, for example, the at least temporary actuation of the steering actuator 18 in a controlled manner.