DE102017222776A1 - Method and system for determining a rack force, operating assistance method for a working device, operation assistance device and working device - Google Patents

Abstract

To determine the most reliable value (Z) possible for a rack-and-pinion force (FZST), a method (S) is proposed for determining the value (Z) of the rack-and-pinion force (F) of a steering system (15) of a working device (10 ') or of a vehicle (10 ) comprising the steps of providing (S1) a set of rack force models (Mi), detecting (S2) operating parameters and in particular driving parameters (Fj) of the underlying working device (10 ') or of the vehicle (10), feeding (S3) from operating parameters or driving parameters (Fj) to a plurality of the rack force models (Mi), determining (S4) a value (Zi) for the rack force (F) from a respective rack power model (Mi), evaluating (S5) the values (Zi) for the Rack force (F) and determining (S6) and providing (S7) a combined resultant value as the rack force value (Z) (F) (a) on the basis of the rack force (F) values (Zi) from the rack and pinion ft models (Mi) and (b) based on a result of the evaluation (S5).

Description

The present invention relates to a method and a system for determining a rack force a working device, an operation assistance method and an operation assistance device for a working device, and a working device as such. In particular, the present invention relates to a driving assistance method and a driving assistance device for a vehicle and a vehicle as such.

In electromechanical steering systems, particularly in the context of steering assist systems or driver assistance systems of work devices, and in particular of vehicles, many functions are controlled or regulated based on the value of the rack force of the underlying steering system as a significant operating parameter. For a robust operation of such a steering system, therefore, the robust determination of the value for the rack force is essential.

From the DE 10 2010 030 986 A1 For example, a method for determining the value of a rack force for a steering apparatus of a vehicle is known in which a component of the rack force for a driving operation in a first model and a component of the rack force for a parking operation in a second model are calculated.

The DE 10 2008 042 666 A1 relates to disturbance compensation in estimating a rack force using a single observer model.

The US 2017/0096161 A1 describes a method and apparatus for steering control in which various operating and driving parameters are used to calculate a rack force.

Such known devices and / or methods for determining the value of the rack-and-pinion force are optimized for specific applications, for example, a driving operation or a parking operation.

The invention is therefore based on the object to provide a method and a system for determining the rack force of a steering system and corresponding operation assistance methods and devices and a working device and in particular a vehicle, in which in a particularly reliable manner for a variety of applications, a robust value for a rack force of an underlying steering system can be determined.

The object underlying the invention is in a method for determining a value of a rack-and-pinion force according to the invention with the features of claim 1, in an operation assistance method according to the invention with the features of claim 13, in a system for determining a value of a rack-and-pinion force according to the invention with the features of Claim 14, in an operation assistance device according to the invention with the features of claim 15 and in a working device and in particular a vehicle according to the invention with the features of claim 16 solved. Advantageous developments are the subject of the respective dependent claims.

• - Bereitstellen eines Satzes von Zahnstangenkraftmodellen,
• - Erfassen von Betriebsparametern und insbesondere von Fahrparametern der zu Grunde liegenden Arbeitsvorrichtung oder des Fahrzeugs,
• - Zuführen von Betriebsparametern oder Fahrparametern zu einer Mehrzahl der Zahnstangenkraftmodelle,
• - Bestimmen eines Werts für die Zahnstangenkraft aus einem jeweiligen Zahnstangenkraftmodell,
• - Bewerten der Werte für die Zahnstangenkraft und
• - Bestimmen und Bereitstellen eines kombinierten resultierenden Werts als Wert für die Zahnstangenkraft (a) auf der Grundlage der Werte für die Zahnstangenkraft aus den Zahnstangenkraftmodellen und auf der Grundlage eines Ergebnisses des Bewertens.

According to a first aspect of the present invention, there is provided a method adapted to determine the value of a rack force of a steering system of a working device or a vehicle. The method according to the invention comprises the steps:

• Providing a set of rack force models,
• Detecting operating parameters and in particular driving parameters of the underlying working device or of the vehicle,
• Supplying operating parameters or driving parameters to a plurality of the rack force models,
• Determining a value for the rack force from a respective rack force model,
• - Evaluate the values for the rack power and
• Determining and providing a combined resulting value as the value of the rack force (a) on the basis of the values of the rack force from the rack force models and based on a result of the evaluation.

As a result of the measures provided for in accordance with the invention, that is to say the use of a plurality of rack force models and the evaluation of the values for the rack force derived from the models, the overall result is a value for the rack force which has an increased degree of reliability over a wider range of applications.

In particular, according to the invention, it is also a question of robust rack force determination and / or observation with the aid of a multiple calculation of the value of the rack force with different models, as well as the plausibility of the results and the resulting Avoiding systematic disadvantages of individual models if they were used alone.

A particularly high degree of reliability arises in the method according to the invention if, according to a preferred embodiment, a multilevel concept is used as a basis, in particular a three-level concept, in which a model, in particular for a vehicle level, a steering gear plane and / or a steering-internal level as modeling levels provided and used to calculate the value of the rack power.

Furthermore, with the help of additional observation and / or measurement, an additional learning model can be formed and used, which describes a superordinate model level with the result of the multilevel concept. This additional model acts more or less as an envelope of the models of the multi-level concept and can be used to further increase the robustness of the rack force calculation according to the invention, in particular in transition situations between the optimal operating points of the individual model levels.

Basically, the individual rack force values obtained from the various rack force models can be combined and evaluated in different ways to derive a combined common rack force value.

It is particularly advantageous if, in accordance with a preferred development of the method according to the invention, a majority decision and in particular a 2-out-of-3 decision are derived when evaluating on the basis of the plurality of values and a majority of the plurality of values corresponding to the majority decision for the Rack force selected and based on determining the combined resulting value for the rack force is based. In this case, it can be checked, for example, whether the individual derived values for the rack-and-pinion force with corresponding error limits lie in a common value range and / or which of the derived values for the rack-and-pinion force are out of line in this context and thus neglected or at least less heavily weighted can.

According to another advantageous embodiment of the method according to the invention for determining the value of a rack-and-pinion force, the rack-pin force models and / or values derived therefrom for the rack-and-pinion force are checked for plausibility on the basis of the operating parameters and / or the driving parameters. Thus, there may be a situation where a given model in a given interval or range of values for certain operating or driving parameters has a higher plausibility and reliability in determining the values for the rack force than in any other interval or range of values. In this respect, the plausibility and / or informative value of the various rack force models can be incorporated depending on the operating parameters or driving parameters, for example in the evaluation of the values derived from the models for the rack force.

In this respect, it is of particular advantage when evaluating the values for the rack force derived from the rack force models and / or determining the combined resulting value for the rack force on the basis of the plausibility.

Accordingly, it may be of particular advantage if the rack force models and / or the values derived therefrom for the rack force are taken into account as a function of the plausibility and / or a weighting.

According to another advantageous embodiment of the method according to the invention, it is provided that the combined resulting value for the rack-and-pinion force is made available directly or via a signal representative of this value. The corresponding representative signal can be used, for example, as a control variable in an underlying steering system.

In principle, all models can be used, from which a value for a rack force can be derived. In this respect, the type and number of rack power models used is basically arbitrary and, for example, adapted to a particular application.

Thus, according to another embodiment of the method according to the invention, in a model of the set of rack force models, the value of a rack force can be determined as a force sum in equilibrium of forces on a steering system of the underlying working device or of the vehicle.

This can in particular be done by detecting a driver's manual torque, a support force of a steering assistance unit and / or friction / inertial forces and / or on the basis of the following relationship ( 1 ) $$\text{Z1}={\text{M}}_{\text{H}}/{\text{i}}_{\text{L}}+{\text{F}}_{\text{U}}+{\text{F}}_{\text{friction}},$$

In this context ( 1 ) designated M _H the value of the driver's hand torque, i _L the value of one Translation factor and / or an effective radius of an underlying steering pinion, F _U the value of the supporting force and F _rubbing the value of the friction / inertial forces.

In this case, to determine the support force on the steering system measurable variables, in particular electrical variables, detected and evaluated in particular via a Kalman filter, neural networks and / or other learning systems.

In another alternative development of the method according to the invention, it is provided that, in a model of the set of rack force models, the value of a rack-and-pinion force is determined as a force sum in the equilibrium of forces on the overall apparatus or on the entire vehicle, on the basis of overall apparatus signals or overall vehicle signals, in particular by detection a steering wheel angle, a driving speed, a lateral acceleration and / or lateral forces from a one-track model or from a two-track model of the working device or the vehicle and / or on the basis of the following relationship ( 2 ) $$\text{Z2}={\text{I}}_{\text{H}}/\text{I}\cdot {\text{i}}_{\text{S}}\cdot {\text{F}}_{\text{Y}},$$

Designate I _H / I the center of gravity with the underlying wheelbase I and the distance I _H a rear axle to a vehicle center of gravity, i _p the translation of an axle kinematics between a radius angle and a displacement of an underlying tie rod and F _Y an acting shear force in the center of gravity of the vehicle.

In another alternative embodiment of the inventive method it is provided that in a model of the set of rack force models the value of a rack force is determined from signals and / or values of electric currents for operating an electric motor of an underlying steering assistance system, preferably using a Kalman filter, of neural networks and / or other learning systems, possibly including temperature signals and / or angular velocity signals from an engine output shaft.

In order to further improve the reliability of the values for a rack force derived from the models and, in particular, the combined and resultant value for the rack force, it is advantageous if a value for a rack force originating from a respective model as a primary value for the rack force is followed by a subsequent estimation method is supplied and derived therefrom, taking into account a measured signal matrix and / or a learning method, in particular based on neural networks and / or a Kalman filter, a corrected value for the rack force.

According to a further aspect of the present invention, an operation assistance method and in particular a driving assistance method for a general working device and in particular for a vehicle is also provided. In the operation assistance method or the driver assistance method according to the present invention, the operation of an underlying work apparatus and in particular an underlying vehicle is controlled or regulated on the basis of a value for a rack force. In the proposed method, the value of the rack force is determined by the method of determining the value of a rack force according to the invention.

Furthermore, the present invention also provides a system for determining a rack force of a steering system of a working device, in particular of a vehicle. The proposed system is adapted to carry out a method for determining the value of a rack-and-pinion force according to the present invention or the operation assistance method or the driver assistance method according to the invention.

• - einer Einheit zum Bereitstellen eines Satzes von Zahnstangenkraftmodellen,
• - einer Einheit zum Erfassen von Betriebsparametern und insbesondere von Fahrparametern der zu Grunde liegenden Arbeitsvorrichtung und insbesondere des zu Grunde liegenden Fahrzeugs,
• - einer Einheit zum Zuführen der Betriebsparameter und insbesondere der Fahrparameter zu einer Mehrzahl der Zahnstangenkraftmodelle,
• - einer Einheit zum Bestimmen eines Werts für die Zahnstangenkraft aus einem jeweiligen Zahnstangenkraftmodell,
• - einer Einheit zum Bewerten der Werte für die Zahnstangenkraft und
• - einer Einheit zum Bestimmen und Bereitstellen eines kombinierten resultierenden Werts für die Zahnstangenkraft (a) auf der Grundlage der Werte für die Zahnstangenkraft aus den Zahnstangenkraftmodellen und (b) auf der Grundlage eines Ergebnisses des Bewertens.

In particular, the system according to the invention is designed with

• a unit for providing a set of rack force models,
• a unit for detecting operating parameters and in particular driving parameters of the underlying working device and in particular of the underlying vehicle,
• a unit for supplying the operating parameters and in particular the driving parameters to a plurality of the rack force models,
• a unit for determining a value of rack force from a respective rack force model,
• a unit for evaluating rack power values and
• a unit for determining and providing a combined resultant value for the rack force (a) on the basis of the values of the rack force from the rack force models; and (b) based on a result of the evaluation.

Furthermore, the present invention also provides an operation assistance device, in particular a driving assistance device for a Working device and in particular for a vehicle. The proposed operating device is set up to carry out a method according to the invention for determining the value of a rack-and-pinion force of a steering system of a working device, in particular of a vehicle, and in particular a corresponding operating assistance method or driver assistance method. In particular, the operation assistance device or driving assistance device has a system according to the invention.

Furthermore, the present invention also provides a working device, in particular a vehicle, which is set up to carry out a method according to the invention for determining the value of a rack-and-pinion force of a steering system or corresponding operating assistance method or driver assistance method or to be used in such methods.

The proposed operation assistance device or driving assistance device has in particular an embodiment of the system according to the invention.

Finally, the present invention also provides a working device, and in particular a vehicle, which are likewise configured to carry out the method according to the invention for determining the value of a rack-and-pinion force of a steering system and / or the operating assistance method or driving assistance method according to the invention or to be used in such a method.

In particular, for this purpose, the proposed working device and the proposed vehicle can have an operating assistance device or driving assistance device configured according to the invention and in particular the system according to the invention.

list of figures

• 1 beschreibt schematisch nach Art eines Flussdiagramms eine Ausführungsform des erfindungsgemäßen Verfahrens und Systems zum Bestimmen des Werts einer Zahnstangenkraft eines Lenksystems einer Arbeitsvorrichtung oder eines Fahrzeugs.
• 2 bis 4 beschreiben schematisch Aspekte verschiedener Zahnstangenkraftmodelle, die bei einer Ausführungsform des erfindungsgemäßen Verfahrens und Systems einsetzbar sind.

Further details, features and advantages of the invention will become apparent from the following description and the figures.

• 1 describes schematically in the manner of a flowchart an embodiment of the method and system for determining the value of a rack force of a steering system of a working device or a vehicle according to the invention.
• 2 to 4 describe schematically aspects of various rack force models that can be used in one embodiment of the method and system according to the invention.

The following are with reference to the 1 to 4 Embodiments and the technical background of the invention described in detail. Identical and equivalent as well as equivalent or equivalent elements and components are designated by the same reference numerals. Not in every case of their occurrence, the detailed description of the designated elements and components is reproduced.

The illustrated features and other properties can be isolated in any form from each other and combined with each other, without departing from the gist of the invention.

1 describes schematically in the manner of a flow chart an embodiment of the method according to the invention S and the system according to the invention 100 to determine the value Z a rack-and-pinion force F _ZST a steering system 15 a working device 10 ' or a vehicle 10 ,

In a first step S1 of the procedure S or in connection with a first unit 1 of the system 100 becomes a set of a plurality of rack force models Wed. provided. The individual rack models Wed. For example, they may be stored in a memory device as procedures, functions, or the like, or as components of an ASIC, and then upon calling and supplying appropriate parameters, a value Zi of the respective model Wed. as value for a rack-and-pinion force F _ZST deliver.

In a second step S2 of the procedure S or in connection with a second unit 2 of the system 100 become operating parameters, for example in the sense of driving parameters fj , detected, for example, by sensors or based on data acquired by sensors by means of a corresponding numerical evaluation.

In a subsequent step S3 of the procedure S or in the context of a unit 3 of the system 100 become the operating parameters or driving parameters fj models Wed. from the set of rack force models fed as input and in connection with a subsequent step S4 and a corresponding unit 4 values Zi for the rack power F _ZST from a respective rack force model Wed. detected.

In this way, a corresponding set of values is created Zi the rack power F _ZST namely, according to the set of rack force models Wed. ,

In a subsequent step S5 of the procedure S or in the context of a unit 5 of the system 100 then those from the models Wed. determined values Zi for the rack power F _ZST assessed, for example, in terms of its plausibility and / or the scope of the underlying model Wed. based on the operating parameters or driving parameters fj ,

In the following step S6 of the procedure S or in connection with another unit 6 of the system 100 will then be based on the values Zi for the rack power F _ZST and, where appropriate, taking into account the plausibility of the values and their underlying models Wed. and considering a possible weighting, a combined resulting value Z for the rack power F _ZST determined, as a value of a function or assignment f which the values Zi from the models Wed. receives as input parameter and the combined resulting value Z for the rack power F _ZST supplies. Finally, in step S7 of the procedure S or in connection with another unit 7 of the system 100 the determined combined resulting value Z for the rack power F _ZST directly or indirectly, for example, as a correspondingly representative signal, for example, to be used in a control method or method.

The 2 to 4 describe schematically aspects of different rack force models M1 . M2 . M3 which in one embodiment of the method according to the invention S and systems 100 can be used.

wobei dort M_H den Wert des Fahrerhandmoments, iL den Wert eines Übersetzungsfaktors und/oder eines effektiven Radius eines zu Grunde liegenden Lenkritzels, F_U den Wert der Unterstützungskraft und F_Reib den Wert der Reibungs-/Trägheitskräfte bezeichnen. 2 describes schematically a first possible model M1 for the determination of the value Z1 the rack power F _ZST in which the value Z1 a rack-and-pinion force F _ZST as a force sum in the balance of power at a steering system of the underlying working device 10 ' or the vehicle 10 is determined, for example by detecting a driver's manual torque M _H , a support force F _U a steering assistance unit 15 and / or frictional / inertial forces F _rubbing and / or based on the following relationship ( 1 ) $$\text{Z1}={\text{M}}_{\text{H}}/{\text{i}}_{\text{L}}+{\text{F}}_{\text{U}}+{\text{F}}_{\text{friction}}.$$

being there M _H the value of the driver's manual torque, iL the value of a ratio factor and / or an effective radius of an underlying steering pinion, F _U the value of the supporting force and F _rubbing denote the value of the friction / inertial forces.

3 schematically describes a second possible model M2 for the determination of the value Z2 the rack power F _ZST in which the value Z2 a rack-and-pinion force F _ZST is determined as a force sum in equilibrium of forces on the basis of total device signals or total vehicle signals. This can be done, for example, by detecting a steering wheel angle, a driving speed, a lateral acceleration and / or lateral forces from a single-track model or from a two-track model of the working device 10 ' or the vehicle 10 and / or based on the following relationship ( 2 ) $$\text{Z2}={\text{I}}_{\text{H}}/\text{I}\cdot {\text{i}}_{\text{s}}\cdot {\text{F}}_{\text{Y}}\cdot {\text{i}}_{\text{S}},$$

Designate I _H / I the center of gravity with the underlying wheelbase I and the distance I _H a rear axle to a vehicle center of gravity, i _p the translation of an axle kinematics between a radius angle and a displacement of an underlying tie rod and F _Y a transverse force acting in the center of gravity of the vehicle.

4 Finally, schematically describes a third possible model M3 for the determination of the value Z3 the rack power F _ZST in which the value Z3 the rack power F _ZST is determined from signals and / or values of electrical currents for operating an electric motor 12 an underlying steering assistance system 15 , preferably using a Kalman filter and / or neural networks 11 , Optionally, this may be done by including temperature signals and / or angular velocity signals from an engine output shaft or other parameters or variables.

These and other features and characteristics of the present invention will be further elucidated with reference to the following statements:

For the lateral dynamic operation of a vehicle, the driving condition and the driving environment are decisive influencing factors. Both human and autonomous or semi-automated driving systems rely on the feedback of information about these drivers for the purpose of safely traversing a vehicle.

While lateral dynamic variables such as the lateral acceleration or the yaw rate reflect the current driving state with the inertia of the respective vehicle, the tire side force represents the initiator of the lateral dynamic chain of action.

The driving state variables are measurable in comparison with the tire side force with little effort, but always with a time lag. The tire side force acts on the axle kinematics as a rack and pinion force on a steering and can only be determined by consuming and expensive measurement technology.

For electromechanical steering systems, it is also possible to design algorithms for monitoring the adjacent rack force on the basis of the sensors available in the steering system. The design of the algorithms depends largely on the requirements of further use.

The prior art does not provide a method of robustly determining the value of a rack-and-pinion force that can be used independently of a specific application.

Known calculation methods are optimized for either high amplitude fidelity or high phase fidelity.

Furthermore, the known approaches contain many parameters which are difficult to detect and which also frequently vary in the context of production variability and wear, such as e.g. Friction.

Efficiencies are very expensive to determine, since these are dependent on the current load and direction of movement of the steering system.

As a result, the development of methods and systems for determining the value of a rack-and-pinion force is comparatively expensive, and the developed function can be used only in a very limited range.

In steer-by-wire steering systems, over conventional electromechanical steering systems, such as e.g. EPS, additional requirements. With the elimination of a steering column, there eliminates the torque sensor. This has hitherto been used to determine the hand torque introduced by the driver.

Furthermore, steer-by-wire systems with control units and motors must be driven, which are redundant due to the required reliability.

As a result, additional friction, inertia and elasticity are present in the system, which makes the calculation more complex than in a conventional EPS steering.

Additional measuring signals must also be taken into account.

An optimization of the rack-power observation is achieved in the present invention based on a redundant calculation of rack force.

The advantage of this approach is the combination of different calculation methods in the sense of different rack force models Wed. in a way that altogether, when working together, offsets the respective disadvantages of a method.

A first model M1 or a first method, for example, in a rack force observation, in which the force sum in the balance of power on the steering system 15 from the influence of the driver, namely the driver's hand moment M _H , the support force F _U and the friction or inertial forces F _rubbing on the metrologically not directly detected rack power F _ZST lets close, like this in 2 is shown.

For the exact determination of the support force F _U For example, a Kalman filter can be used. This approach takes into account the steering system 15 measurable sizes. Possible disadvantages with changing frictional forces or stick-slip effects of the steering are to be compensated according to the invention by the combination with other rack force models.

A second model M2 or a second method is to calculate the value of rack force based on total vehicle signals.

On the basis of eg values for the steering wheel angle, for the vehicle speed can be concluded with the help of a model vehicle image, such as a single-track model or in the manner of a two-track model on the lateral acceleration and thus on the lateral forces, as in 3 is shown.

The value of rack power F _ZST calculated from the lateral force and the transmission ratio of the axle kinematics. Since the lateral acceleration is detected by standard sensors, the parameters of the vehicle model used can be updated or optimized in real time and / or online.

For a third model M3 or a corresponding third method, the signals are used, which are detected in the context of operating an electric motor. These include, in particular, the measured electrical currents, which provide information about the assistance torque provided by the electric motor.

Furthermore, for example, temperature signals and / or values for the angular velocity of the engine output shaft can be used to obtain conclusions about the applied engine torque. To determine the resulting engine torque and thus - via the balance of power of a steering - The applied rack force can be calculated using methods such as Kalman filters, neural networks, and / or other learning techniques, as described in 4 is shown.

The calculation of the value of the rack force based on the presented approaches of the models M1 to M3 or on the basis of additional models provides in the best case, three identical rack force signals. For further cases, however, deviations between the different calculation methods may occur. The goal of optimized rack force calculation therefore requires the evaluation and weighting of the determined rack force signals. In a first step, the selection of a valid signal based on a majority vote can be made.

In the evaluation of the individual models M1 to M3 generated values Z1 to Z3 for the rack power F _ZST the following procedure is conceivable:

If the result of a calculation method - that is one of the models M1 to M3 - deviates greatly from the results of the other two methods or models, the deviation is assessed as faulty and it will be the remaining values for the rack force F _ZST or the corresponding signals. The selection process can also be adapted according to the requirements of the quality of the rack force calculation. The evaluation of driving conditions can represent a method, for example. For quasi-stationary maneuvers in which the measured lateral acceleration allows a comparatively robust rack force calculation as a reference, a high weighting is assigned to the second method.

1. 1. in der Ebene elektrischer Größen eines Unterstützungsmotors und/oder eines Steuergerät einer Lenkung,
2. 2. in der Ebene mechanischer Größen der Lenkung und
3. 3. in der Ebene von Fahrzeuggrößen.

That's how the values become Zi for the rack power F _ZST considered in three consecutive levels, namely

1. 1. in the plane of electrical quantities of a support motor and / or a control unit of a steering,
2. 2. in the level of mechanical sizes of the steering and
3. 3. in the plane of vehicle sizes.

Through a 2-out-of-3 decision, the steering system can 15 decide without external input, which method provides the most accurate results in each driving situation.

In order to avoid signal jumps, the transitional situations between the calculation methods are especially considered. Ramps over multiple time steps or the use of filter algorithms ensure a continuous transition.

Although the aspects and advantageous embodiments of the invention have been described in detail with reference to the embodiments explained in connection with the accompanying drawings, modifications and combinations of features of the illustrated embodiments are possible for the skilled person, without departing from the scope of the present invention, the scope of protection the appended claims are defined.

LIST OF REFERENCE NUMBERS

1

Unit to deploy S1 a set of rack force models Wed.

2

Unit to capture S2 of operating parameters / driving parameters fj

3

Unit for feeding S3 of operating parameters / driving parameters fj

4

Unit for determining S4 of a value Zi for the rack power F _ZST

5

Unit for rating S5 the values Zi for the rack power F _ZST

6

Unit for determining S6 a combined resulting value Z for the rack power F _ZST

7

Unit to deploy S7 of the combined resulting value Z for the rack power F _ZST

10

vehicle

10 '

working device

11

neural network

12

Electric motor, support motor

15

steering system

100

system

fj

Driving parameters, with j = 1, 2, 3, ...

F _rubbing

(Value of a) friction force

F _U

(Value of one) supporting force

F _Y

acting in the vehicle center of gravity lateral force

F _ZST

(Value of a) rack force

I

wheelbase

I _H

Distance rear axle to the vehicle center of gravity

I _H / I

Priority reserve

i _L

Translation factor and / or effective radius of an underlying steering pinion

i _p

Translation of an axle kinematics between a radius angle and a displacement of an underlying track rod

M _H

(Value of one) driver's hand moment (s)

Wed.

Rack Force Model, with i = 1, 2, 3, ...

S

method

S1

Provide S1 a set of rack force models Mi

S2

To capture S2 of operating parameters / driving parameters fj

S3

Respectively S3 of operating parameters / driving parameters fj

S4

Determine S4 of a value Zi for the rack power F _ZST

S5

assess S5 the values Zi for the rack power F _ZST

S6

Determine S6 a combined resulting value Z for the rack power F _ZST

S7

Provide S7 of the combined resulting value Z for the rack power F _ZST

Z

(combined / resulting) value for the rack force F _ZST

Zi

Value of a rack-and-pinion force F _ZST from a rack power model Wed. , with i = 1, 2, 3, ...

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102010030986 A1 [0003]
• DE 102008042666 A1 [0004]
• US 2017/0096161 A1 [0005]

Claims (16)

Method (S) for determining the value (Z) of a rack-and-pinion force (F _ZST ) of a steering system (15) of a working device (10 ') or of a vehicle (10), comprising the steps of: - providing (S1) a set of rack force models (Mi ), - acquiring (S2) operating parameters and in particular driving parameters (Fj) of the underlying working device (10 ') or the vehicle (10), - supplying (S3) operating parameters or driving parameters (Fj) to a plurality of the rack force models ( Mi), - determining (S4) a value (Zi) for the rack force (F _ZST ) from a respective rack force model (Mi), - evaluating (S5) the values (Zi) for the rack force (F _ZST ) and - determining (S6 ), and providing (S7) a combined resulting value as a value (Z) for the rack force (F _ZST) (a) on the basis of the values (Zi) (for the rack force F _ZST) (from the rack force models Mi) and (b) based on a result of the rating (S5). Method (S) according to Claim 1 in which a multilevel concept is used as a basis, wherein for each of a vehicle level, a steering gear plane and / or an in-steering plane as modeling planes, a model for calculating the value of the rack force is provided and used. Method (S) according to Claim 2 in which, by means of an additional observation and / or measurement, an additional learning model is developed and used, which describes a superordinate model level with the result of the multilevel concept. Method (S) according to one of the preceding claims, in which in the evaluation (S5) on the basis of the plurality of values (Zi) a majority decision and in particular a 2-out-of-3 decision are derived and thereby a majority - corresponding to the majority decision is selected from the plurality of rack force ( _ZZ ) values (Zi) and based on the determination (S6) of the combined resultant rack power value (Z) ( _ZZST ). Method (S) according to one of the preceding claims, in which the rack force models (Mi) and / or values (Zi) derived therefrom for the rack force (F _ZST ) are checked for plausibility on the basis of the operating parameters and / or the driving parameters (Fj) , Method (S) according to Claim 5 in which the evaluation (S5) and / or the determination (S6) are made on the basis of the plausibility. Method (S) according to Claim 5 or 6 in which the rack force models (Mi) and / or derived therefrom values (Zi) for the rack force (F _ZST ) are taken into account as a function of the plausibility and / or a weighting. Method (S) according to one of the preceding claims, in which the combined resultant value (Z) for the rack-and-pinion force (F _ZST ) is provided directly or via a signal representative of this value. Method (S) according to one of the preceding claims, in which - in a model (M1) of the set of rack-power models (Mi), the value (Z1) of a rack-and-pinion force (F _ZST ) is expressed as a force balance in force equilibrium on a steering system (15) Underlying working device (10 ') or the vehicle (10) is determined, in particular by detecting a driver's manual torque (M _H ), an assisting force (F _U ) of a steering support unit and / or friction / inertial forces (F _friction ) and / or on the basis of the following relationship (1) $$\text{Z1}={\text{M}}_{\text{H}}/{\text{i}}_{\text{L}}+{\text{F}}_{\text{U}}+{\text{F}}_{\text{friction}}.$$

wherein M is _H the value of driver's hand torque iL the value of the translation factor and / or an effective radius of an underlying steering pinion, F _U the value of the assistance force and F _friction value of the friction call / inertial forces, - wherein in particular for determining the assist force on the steering system (15) measurable variables, in particular electrical variables, detected and evaluated in particular via a Kalman filter or neural networks. Method (S) according to one of the preceding claims, wherein in a model (M2) of the set of rack force models (Mi) the value (Z2) of a rack force (F _ZST ) is determined as a force balance in force equilibrium on the basis of total device signals or total vehicle signals, in particular by detecting a steering wheel angle, a driving speed, a lateral acceleration and / or lateral forces from a one-track model or from a two-track model of the working device (10 ') or of the vehicle (10) and / or on the basis of the following relationship (2) $$\text{Z2}={\text{I}}_{\text{H}}/\text{I}\cdot {\text{F}}_{\text{Y}}\cdot {\text{i}}_{\text{S}}.$$

where I _H / I the center of gravity with the underlying wheelbase I and the distance I _{H of} a rear axle to a vehicle center of gravity, i _S the translation of an axle kinematics between a radii angle and a displacement of an underlying track rod and F _{Y of} an acting lateral force in the vehicle's center of gravity describe. Method (S) according to one of the preceding claims, wherein in a model (M3) of the set of rack force models (Mi) the value (Z3) of a rack force (F _ZST ) is determined from signals and / or values of electric currents for operating an electric motor (12) an underlying steering assist system, preferably using a Kalman filter and / or neural networks (11), optionally incorporating temperature signals and / or angular velocity signals from an engine output shaft. Method (S) according to one of the preceding claims, in which a value (Zi) for a rack-and-pinion force (F _ZST ) originating from a respective model (Mi) is supplied as the primary value for the rack force to a downstream estimation method and from there using a measurement signal matrix and / or a learning method, in particular based on neural networks or Kalman filter, a corrected value for the rack force (F _ZST ) is derived. Operational assistance method or driver assistance method for a working device (10 ') or for a vehicle (10), in which the operation of an underlying working device (10') or an underlying vehicle (10) is based on a value (Z) for a rack force (F _ZST ) is controlled, and - wherein the value (Z) for the rack force (F _ZST ) is determined by a method according to any one of Claims 1 to 12 is determined. System (100) for determining a rack-and-pinion force (F _ZST ) of a steering system (15) of a working device (10 ') or of a vehicle (10), which is set up, a method according to one of Claims 1 to 13 be implemented or used in such a method, and - which is in particular formed with - a unit (1) for providing (S1) a set of rack force models (Mi), - a unit (2) for detecting (S2) of operating parameters and in particular of driving parameters (Fj) of the underlying working device (10 ') or of the underlying vehicle (10), - a unit (3) for supplying (S3) the operating parameters and in particular the driving parameters (Fj) to a plurality of the rack force models (Mi), - a unit (4) for determining (S4) a value (Zi) for the rack force (F _ZST ) from a respective rack force model (Mi), - a unit (5) for evaluating (S5) the values (Zi ) for the rack force (F _ZST ) and - a unit (6, 7) for determining (S6) and providing (S7) a combined resulting value (Z) for the rack force (F _ZST ) (a) on the basis of the values ( Zi) for the rack force (F _{Z ST} ) from the rack force models (Mi) and (b) based on a result of the evaluation (S5). Operational assistance device or driving assistance device for a working device (10 ') or for a vehicle (10), which is set up, a method (S) according to one of Claims 1 to 13 and which in particular a system (100) according to Claim 14 having. Working device (10 ') or vehicle (10), - which is set up, a method (S) according to one of Claims 1 to 13 be executed or with such a method (S) to be used and / or - which with a Betriebsassistenzvorrichtung and in particular with a system according to Claim 14 and / or with a driving assistance device Claim 15 is trained.

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