阅读说明：本技术 用于运行机动车的转向系统的方法和装置 (Method and device for operating a steering system of a motor vehicle ) 是由 L·施托尔策 Y·斯克利亚连科 C·马特斯 H·弗里克 于 2021-06-09 设计创作，主要内容包括：本发明涉及一种用于运行机动车的转向系统的方法和装置,该方法用于运行带有机电的转向干预系统(10)的转向系统(1),其带有多个冗余的控制路径(11a,11b),其中,每个控制路径(11a,11b)具有控制单元(12a,12b)、功率单元(13a,13b)和伺服马达的绕组回路(14a,14b),其中,在每个控制单元(12a,12b)中设置有调节参量单元(15a,15b),以便根据输入参量来提供调节参量(S-(a),S-(b)),其中,将所有调节参量单元(15a,15b)的调节参量(S-(a),S-(b))取平均,其中,通过每个控制单元(12a,12b)根据平均的调节参量来提供理论调节参量(S-(a理论),S-(b理论))。(The invention relates to a method and a device for operating a steering system of a motor vehicle, for operating a steering system (1) having an electromechanical steering intervention system (10) with a plurality of redundant control paths (11a,11b), wherein each control path (11a,11b) has a control unit (12a,12b), a power unit (13a,13b) and a winding circuit (14a,14b) of a servomotor, wherein a manipulated variable unit (15a,15b) is provided in each control unit (12a,12b) in order to provide a manipulated variable (S) as a function of an input variable a ,S b ) Wherein all the regulation is referred toRegulating variable (S) of the quantity units (15a,15b) a ,S b ) Averaging, wherein a set control variable (S) is provided by each control unit (12a,12b) as a function of the averaged control variable Theory of a ,S Theory of b )。)

1. Method for operating a steering system (1) having an electromechanical steering intervention system (10) with a plurality of redundant control pathsA path (11a,11b), wherein each control path (11a,11b) has a control unit (12a,12b), a power unit (13a,13b) and a winding circuit (14a,14b) of the servomotor, wherein a control variable unit (15a,15b) is provided in each control unit (12a,12b) in order to provide a control variable (S) as a function of an input variable_a,S_b) Wherein the control variables (S) of all control variable units (15a,15b) are measured_a,S_b) Averaging, wherein a set control variable (S) is provided by each control unit (12a,12b) as a function of the averaged control variable_{Theory of a},S_{Theory of b})。

2. Method according to claim 1, wherein the averaged manipulated variable is used as a theoretical manipulated variable (S)_{Theory of a},S_{Theory of b}) Respectively to the power cells (13a,13b) of the associated control path (11a,11 b).

3. The method according to claim 1 or 2, wherein the regulating variable unit (15a,15b) has a respective regulation, in particular a steering position regulation, with at least one integrator contribution, wherein the integrator contribution is influenced in each case as a function of the average regulating variable.

4. Method according to claim 3, wherein said theoretical regulating variable (S) is used_{Theory of a},S_{Theory of b}) And the regulating variable (S)_a,S_b) The difference between to run the integrator share.

5. Method according to claim 4, wherein the theoretical regulating quantity (S) is to be set at_{Theory of a},S_{Theory of b}) And the regulating variable (S)_a,S_b) The difference between them is weighted.

6. The method according to claim 3 or 4, wherein the integrator share is controlled based on events in order to achieve anti-saturation.

7. A device for operating a steering system (1) having an electromechanical steering intervention system (10) having a plurality of redundant control paths (11a,11b), wherein each control path (11a,11b) has a control unit (12a,12b), a power unit (13a,13b) and a winding circuit (14a,14b) of a servomotor, wherein a control variable unit (15a,15b) is provided in each control unit (12a,12b) in order to provide a control variable (S) as a function of an input variable_a,S_b) Wherein the control paths (11a,11b) are designed to regulate the control variables (S) of all the control variable units (15a,15b)_a,S_b) Averaging and providing a set control variable (S) by each control unit (12a,12b) as a function of the averaged control variable_{Theory of a},S_{Theory of b})。

8. Steering system (1) for steering the wheels of a motor vehicle, having a servomotor for generating a steering force or a steering torque, and having a device according to claim 7.

Technical Field

The invention relates to a motor vehicle, in particular a motor vehicle with an automatic steering system for automatically fulfilling a steering demand.

Background

Electromechanical steering systems are used in motor vehicles in order to generate an electrically generated steering torque or an electrically generated steering force. Such steering systems are used, for example, to implement driver assistance functions (e.g., lane keeping assistance), to assume part of the task of driving operations (e.g., in parking steering assistance), or to autonomously adjust the steering position of the wheels in a steer-by-wire system.

For all these functions, the desired steering requirements are fulfilled and a setpoint manipulated variable (Soll-stellgresse) in the form of a corresponding setpoint manipulated torque or a corresponding setpoint manipulated force is provided. The setpoint manipulated variable is often provided by means of a controller, for example a steering position controller (Lenkstellungsregler).

Since the proper functioning of the steering system is critical for safety, the steering system is completely or partially redundant. In particular, a completely redundant design is required for the steer-by-wire system, since, due to the lack of mechanical connection between the steering wheel and the steered wheels, there is no alternative intervention possibility for the driver in the event of a failure of the steering system.

In principle, two approaches are known for redundant design of the steering control. The steering system is controlled via a Master-control path (steuerungsfad) in a Master/Slave solution (Master/Slave-Konzept). Redundant slave control paths are additionally provided. The slave control path assumes the control of a steering servomotor (Lenkstellmotor) in the event of a failure of the master control path. In the so-called master/master variant, a plurality of equal control paths are provided for actuating a plurality of steering servomotors or a steering servomotor with a plurality of separate winding circuits (wicklungsrepis). Although only a reduced control torque is available for the steering control movement in the event of a failure in one of the control paths, a complete failure (tolausfall) is avoided.

DE 102018108597 a1 discloses a redundant control unit for an electromechanical steering system of a motor vehicle, which has a primary control path and a secondary control path. The primary control path has a primary computational unit, a primary driver stage (Treiberstufe), and a primary power module, while the secondary control path has a secondary computational unit, a secondary driver stage, and a secondary power module, respectively. The power module is used to operate two physically separate motors or a single motor with two winding sets. The torque can be applied to the same shaft by the two physically separated torque generators. Communication between these two control paths is additionally provided via a signal line directly between the computing units.

In the main/main scheme for building the steering controller, the control signal is generated equally for a plurality of winding loops of one or more steering servomotors. This can result in different setpoint control variables due to deviations between the independently determined input signals available, which result in different control torques or different control forces being provided in the plurality of winding loops. Since the two theoretical control variables are taken into account in the positioning of the steering system, the winding loops can possibly also generate interacting control forces or control torques. This applies in particular if the theoretical manipulated variable is generated on the basis of a manipulated variable which optionally has an integrator proportion (integrator). In this case, slight control deviations with different signs on the two control paths can then accumulate and thus lead to differently directed control torques or control forces.

Disclosure of Invention

It is therefore an object of the present invention to provide an improved method for operating a steering system, which is constructed with control according to a master/master scheme. In particular, interacting control paths should be avoided.

The object of the invention is achieved by a method according to the invention for operating a steering system of a motor vehicle and by a device and a steering system according to the invention.

Further embodiments are described in the description.

According to a first aspect, a method for operating a steering system with an electromechanical steering intervention system is provided, having a plurality of redundant control paths, wherein each control path has a control unit, a power unit and a winding circuit of a servomotor, wherein a manipulated variable unit is provided in each control unit in order to provide a manipulated variable as a function of an input variable, wherein the manipulated variables of all manipulated variable units are averaged, wherein a setpoint manipulated variable is provided by each control unit as a function of the averaged manipulated variable.

In particular, the averaged manipulated variable can be correspondingly transmitted as a setpoint manipulated variable to the power cells of the relevant control path.

In the main/main concept for the control of the steering system, two or more equal control paths are provided, each of which comprises a control unit for providing a set control variable for the power unit in order to convert the set control variable into a corresponding motor actuation, and a winding circuit for generating a control torque corresponding to the set control variable or a control force corresponding to the set control variable. The winding loops may be disposed in one or more steering servomotors.

Due to deviations of the input variables of the equivalent control paths, for example due to the steering position or steering angle, optionally longitudinal and transverse accelerations (depending on the control scheme) and rack position, which are measured differently (i.e. at other times, other sensors), the control unit can generate different setpoint control variables, which result in different control torques/control forces generated by the winding circuits. Furthermore, deviations in the measured steering displacement speed or steering angle speed for cascaded regulators can also be relevant.

Depending on the range of functions performed by the control unit, slight deviations of the input variables with different signs in the two control paths can be accumulated, so that theoretical manipulated variables with different signs can be formed. The sum of the actuating torques is usually correct here and corresponds to the objective of the control function to be implemented, but the winding circuit consumes an unnecessarily large amount of electrical energy here, since its actual actuating torque/actuating force interacts. The availability and useful life of components of the control path may be negatively affected by excessive thermal stress.

It is therefore provided according to the method described above that the setpoint manipulated variables of a plurality of control paths, which are provided at the outputs of the respective control units, are correspondingly provided to the other control paths. The control path is then set to perform an averaging of the two control variables and to generate a corresponding control torque/control force.

Interaction of the control paths can thus be prevented, since the averaging of the two setpoint manipulated variables takes place at the level of digital data processing without torque or force superposition.

In particular, the manipulated variable unit can have a control, in particular a steering position control, with an integrator proportion, wherein the integrator proportion is operated as a function of the averaged manipulated variable. Furthermore, the difference between the actual manipulated variable and the actual manipulated variable can be used to influence the integrator contribution.

In particular, the integrator contribution of the steering position adjustment can lead to a deviation of the theoretical adjustment variables of the two control paths from one another and thus to different signs of the adjustment variables. Even in the case of two control paths, slight control deviations with different signs are accumulated, so that an increased setpoint control variable with different signs is formed.

Thereby negatively affecting the regulator dynamics of the regulation (Reglerdynamik). By taking the averaged setpoint manipulated variable into account in the integrator contributions, the adjustments performed in the plurality of control units are mutually limited and excessive differences between the integrator contributions and thus excessive deviations of the setpoint manipulated variable are prevented. The adjusted integrator contribution is reduced by influencing the integrator contribution by means of the difference between the averaged theoretical manipulated variable and the theoretical manipulated variable of each control path. This may reduce or avoid the so-called saturation effect (Windup-Effekt) of the adjusted integrator.

The averaging of the setpoint manipulated variables as the output of the control unit takes into account the mutual divergence (Auseinanderlaufen) of the setpoint manipulated variables so that no opposing actuating torques or actuating forces are caused by the respective winding circuits.

It can be provided that the difference between the theoretical manipulated variable and the manipulated variable is weighted. The influence of the averaging of the theoretical manipulated variables on the respective integrator contribution can be adjusted by setting a weighted feedback (rueckfuehung) of the difference between the theoretical manipulated variable output in each control path and the averaged theoretical manipulated variable.

It may be provided that the integrator contribution is controlled on the basis of events in order to achieve anti-saturation.

This can be achieved, for example, by setting (freezing) the integration to a suitable value and temporarily suspending the integration if one or more of the following criteria are met:

exceeding a certain deviation between the theoretical manipulated variables;

below a certain adjustment difference and

-reaching a saturation limit.

After the integrator reset (Ruecksetzen), it can be set to the average value of the integrator contributions of the two control paths or to a preset value deviating from the average value in order to optimize the dynamics in the saturation behavior.

According to a further aspect, a steering system for operating a steering intervention system with an electromechanical system is provided, having a plurality of redundant control paths, wherein each control path has a control unit for a servomotor, a power unit and a winding circuit, wherein a manipulated variable unit is provided in each control unit in order to provide a manipulated variable as a function of an input variable, wherein the control paths are designed to average the manipulated variables of all manipulated variable units and to provide a setpoint manipulated variable as a function of the averaged manipulated variable by each control unit.

According to a further aspect, a steering system for steering the wheels of a motor vehicle is provided, having one or more servomotors and/or one or more winding circuits for generating a steering force or a steering torque, and having the above-described device.

Drawings

Embodiments are explained in detail below with reference to the drawings. Wherein:

FIG. 1 shows a schematic view of a steering system for a motor vehicle;

FIG. 2 shows a block diagram of a control system with two control paths for providing a steering adjustment torque;

fig. 3 shows a block diagram of a steering control system according to a further embodiment, in which the manipulated variable difference is taken into account in the manipulated variable unit; and

fig. 4 shows a block diagram of a steering control system according to a further embodiment, in which the manipulated variable difference is taken into account in the manipulated variable unit and in the truncation of the change of the manipulated variable (Abgriff).

Detailed Description

Fig. 1 shows a schematic representation of a steering system 1 with an electromechanical steering intervention system 10. The steering system 1 has a steering gear 3, which has a pinion 4 and a rack 5 in order to transmit a manual steering torque or a manual steering force, which is applied manually, for example via a steering wheel 6 and a steering rod 7, to the rack 5. The rack 5 is coupled to steered wheels 8 to steer them according to the position of the steering rod 7.

The electromechanical steering intervention system 10 of the steering system 1 enables the application of an electrically generated steering torque or steering force for steering assistance or for fully automatic adjustment of the steering position, in particular during automatic driving or during automatic shunting (Rangiervorgang).

The steering intervention system 10 has two (as shown in the illustrated embodiment) or more than two redundant control paths 11a,11b, each of which has a control unit 12a,12b, a power unit 13a,13b and one or more winding circuits 14a,14b of the servomotor which are actuated by the power unit 13a,13 b. The control units 12a,12b are in communication connection.

The winding loops 14a,14b can be arranged in separate servomotors or respectively separately in a common servomotor. In the exemplary embodiment shown, two servomotors act on the steering rod in order to apply a setting torque thereto. In an alternative embodiment, the servomotor can also act directly on the rack and exert a steering force there.

The power units 13a,13b serve to provide the usually digitally provided setpoint variable as an electrical control signal for the winding circuits 14a,14b, so that the winding circuits provide a corresponding steering torque to the steering rod or a corresponding steering force to the rack.

Fig. 2 schematically illustrates an embodiment of the steering intervention system 10 from fig. 1. A first control path 11a with a first control unit 12a, a first power unit 13a and a first winding loop 14a of the servomotor and a second control path 11b with a second control unit 12b, a second power unit 13b and a second winding loop 14b of the common servomotor or of the individual servomotor are identified.

The first and second control units 12a,12b provide the setpoint manipulated variable S for the respective power unit 13a,13b_{Theory of a},S_{Theory of b}Which is the theoretical regulating force or the theoretical regulating moment.

In the exemplary embodiment shown, the control units 12a,12b have a first or a second manipulated variable unit 15a,15b, which generates a manipulated variable S_a,S_bThe power units 13a,13b are controlled as a function of the control variable.

The first manipulated variable S provided in each case for the manipulated variable units 15a,15b is now taken into account in the averaging stages (mistletsgled) 16a,16b_aAnd a second manipulated variable S_bAnd (6) averaging. The averaged manipulated variable is now used as the corresponding theoretical manipulated variable S_{Theory of a},S_{Theory of b}To the respective power unit 13a,13 b. This makes it possible to reduce the theoretical manipulated variable S_{Theory of a},S_{Theory of b}Systematic deviations between and in particular avoiding the control variable S_a,S_bDue to the slight deviations accumulated in the manipulated variable units 15a,15b, a control force or a control torque is formed in the winding loops 14a,14b in opposite directions. In particular, excessive heating of power cells 13a,13b and winding loops 14a,14b is thereby avoided, since parameter S is set_a,S_bThe averaging is performed on a software level without torque or force superposition.

Fig. 3 shows a further embodiment of the steering intervention system 10. In the case of the control variable units 15a,15b, a respective steering position control is carried out there, which has at least one integrator. The steering position control can have a PI controller or a PID controller and can be set to a predefined setpoint steering position. Other forms of adjustment structures with integrator share can also be applied.

The averaged manipulated variables are then supplied to a difference element (differential) 17a,17b in order to calculate the averaged manipulated variables with respect to the corresponding manipulated variables S generated by the corresponding manipulated variable unit 15a,15b_a,S_bAnd the manipulated variable difference is fed to the integrator of the adjustment performed in the manipulated variable unit 15a,15b or is taken into account there. For this purpose, the control variable S to be averaged_a,S_bAnd the averaged control variables of each control path are subtracted from one another and the integrator contribution is loaded. In this way, the integrator contributions of the regulation in the respective regulating variable units 15a,15b can be loaded only with the deviations in the respective differential elements 17a,17 b. This makes it possible to adjust the setpoint variable S corresponding to two variables output by the control unit_{Theory of a},S_{Theory of b}The difference generated by the deviation of (c) compensates the integrator contribution. Saturation of the integrator contribution is thereby effectively prevented.

It may be provided that the integrator contribution is controlled on the basis of events in order to achieve anti-saturation. For this, the integration can be set (frozen) to a suitable value and temporarily suspended if one or more of the following criteria are met:

exceeding a certain deviation between the theoretical manipulated variables;

below a certain adjustment difference and

-reaching a saturation limit.

After the resetting of the integrator, it can be set to the average value of the integrator contributions of the two control paths or to a preset value deviating from this average value in order to optimize the dynamics in the saturation behavior.

Furthermore, this variant prevents, on the one hand, the integrator contributions from being distributed to one another and a residual deviation (which is caused, for example, by a proportional contribution (proportionality) of the steering position control) occurring, and, on the other hand, allows the theoretical control variable to be reduced by averaging.

If necessary, the average manipulated variable can be compared withThe corresponding manipulated variable S actually generated by the corresponding manipulated variable unit 15a,15b_a,S_bIs provided with weights so that the influence on the integrator contribution can be adjusted in this way.

Alternatively, as shown in the steering intervention system 10 of the block circuit diagram of fig. 4, for controlling the power units 13a,13b, the manipulated variable S directly output by the respective control unit 12a,12b can be used_a,S_bSince the output is based directly on the control output (regengusasgang) taking into account the integrator contribution of the steering position control. That is, the averaged manipulated variable is not used for controlling the power units 13a,13b, but rather the manipulated variable S is directly used_a,S_bWhich calculates the integrator contribution based on the averaged manipulated variable as described above. This reduces the operating time in the control loop of the respective control unit, since the averaging corresponds to a filtering.

List of reference numerals

1 steering system

3 turn to drive mechanism

4 pinion

5 Rack

6 steering wheel

7 steering rod

8-steering wheel

10 electromechanical steering intervention system

11a,11b first and second control paths

12a,12b first and second control units

13a,13b first and second power cells

14a,14b winding loop

15a,15b first and second manipulated variable units

16a,16b taking average ring segments

17a,17b differential element S_{Theory of a},S_{Theory of b}Theoretical regulating variable

S_a,S_bAnd adjusting the parameters.