DE102023109635A1 - Method and device for detecting a manual steering intervention in a vehicle with a steer-by-brake function - Google Patents

Abstract

The invention relates to a method and a device (1) for detecting a manual steering intervention (ME) in a vehicle with a steer-by-brake function, wherein in a state estimator (2) on the basis of measured vehicle state variables, including a brake pressure difference (Δp) at a front axle and a speed (v), as well as known parameters of the vehicle, including scrub radius (LRR), kingpin (S), caster (NL), a relaxation length (RL) and/or lateral stiffness (LS) of the tires of the vehicle and a Front axle load (VAL), with a steer-by-brake intervention an expected value (LWe) of a steering angle and expected values for a yaw rate (GRe) and a lateral acceleration (QBe) are calculated, with the expected values (LWe, GRe, QBe) corresponding to measured values of the steering angle (LW), the yaw rate (GR) and the lateral acceleration (QB), whereby if the measured values deviate from the expected values (LWe, GRe, QBe), it is concluded that a manual steering intervention (ME) is present and the steer-by-brake function is switched off.

Description

The invention relates to a method for detecting a manual steering intervention in a vehicle with a steer-by-brake function according to the preamble of claim 1. The invention also relates to a device for detecting a manual steering intervention in a vehicle with a steer-by-brake -Function according to the preamble of claim 6.

A steering intervention in a vehicle can be generated via a braking system (steer-by-brake) and thus offers a considerable cost advantage compared to electric or partially electric steering. An electric or partially electric steering is equipped with a sensor for hands-on detection (steering angle torque or capacitive steering wheel). If a manual steering intervention is detected, assistance systems should be switched off to ensure that the driver retains control of the vehicle.

EP 2 448 795 B1 describes a method for changing the trajectory of a vehicle, the vehicle having a steering assembly including a manual steering device, an actuator configured to provide guidance torque for the steering assembly, at least one pair of ground engaging elements, and a mechanical interconnection between the manual steering device and the ground engaging elements, the method comprising the step of applying a braking force to at least one of the ground engaging elements such that the trajectory of the vehicle is altered, further comprising using a reference generator for steering system control while simultaneously suppressing steering device jitter resulting from the mechanical interconnection , characterized in that the reference generator is configured to continuously receive an input signal indicative of a driver's steering intent and, based on that signal, to output a signal indicative of a desired steering torque, the desired steering torque being associated with the actual steering torque of the vehicle is compared, and wherein the output signal from the reference generator is continuously adjusted by applying the difference between the desired steering torque and the actual steering torque to the actuator such that the desired steering torque is transmitted to the driver.

The invention is based on the object of specifying a novel method and a novel device for detecting a manual steering intervention in a vehicle with a steer-by-brake function.

The object is achieved according to the invention by a method for detecting a manual steering intervention in a vehicle with a steer-by-brake function with the features of claim 1 and by a device for detecting a manual steering intervention in a vehicle with a steer-by-brake -Function with the features of claim 6.

Advantageous configurations of the invention are the subject matter of the dependent claims.

In a method for detecting a manual steering intervention in a vehicle with a steer-by-brake function, in a state estimator based on measured vehicle state variables, including a brake pressure difference on a front axle and a speed, as well as known parameters of the vehicle, including steering scrub radius, spread, caster, a relaxation length and/or lateral stiffness of the tires of the vehicle and a front axle load, in a steer-by-brake intervention an expected value of a steering angle and expected values for a yaw rate and a lateral acceleration are calculated, with the expected values being compared with corresponding measured values of the steering angle, the Yaw rate and the lateral acceleration are compared, with a deviation of the measured values from the expected values, it is concluded that a manual steering intervention is present and the steer-by-brake function is switched off.

According to the present invention, an additional sensor (steering angle torque or capacitive steering wheel) can be eliminated by using a state estimator based on other available and/or observable vehicle state data.

Even if such a sensor continues to be used, if the sensor fails during a steer-by-brake intervention, a manual steering intervention can still be detected.

Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

• 1 eine schematische Ansicht einer Vorrichtung zur Erkennung eines manuellen Lenkeingriffs in einem Fahrzeug, und
• 2 eine schematische Ansicht einer weiteren Ausführungsform der Vorrichtung zur Erkennung eines manuellen Lenkeingriffs in einem Fahrzeug.

show:

• 1 a schematic view of a device for detecting a manual steering intervention in a vehicle, and
• 2 a schematic view of a further embodiment of the device for detection tion of a manual steering intervention in a vehicle.

Corresponding parts are provided with the same reference symbols in all figures.

1 is a schematic view of a device 1 for detecting a manual steering intervention ME in a vehicle, for example in a commercial vehicle, a bus or a passenger car, in particular in a highly automated vehicle with a steer-by-brake function.

The device 1 comprises a state estimator 2 or observer, which, on the basis of measured vehicle state variables and known vehicle geometries and properties, in particular parameters and/or constants, calculates an expected value LW _e of a steering angle and expected values GR _e , QB _e during a steer-by-brake intervention calculated for accelerations.

• - eine Bremsdruckdifferenz Δp, insbesondere an einer Vorderachse des Fahrzeugs,
• - eine Geschwindigkeit v des Fahrzeugs,
• - ein Gewicht G oder eine Masse des Fahrzeugs und/oder deren Verteilung auf die Vorderachse und weitere Achsen des Fahrzeugs, insbesondere eine Vorderachslast VAL.

The relevant vehicle state variables for the expected values of the steering angles LW _e and accelerations GR _e , QB _e are:

• - a brake pressure difference Δp, in particular on a front axle of the vehicle,
• - a speed v of the vehicle,
• - A weight G or a mass of the vehicle and/or its distribution to the front axle and other axles of the vehicle, in particular a front axle load VAL.

• - eine Lenk- und Vorderachsgeometrie des Fahrzeugs, insbesondere ein Lenkrollradius LRR, eine Spreizung S und ein Nachlauf NL,
• - Eigenschaften der Reifen des Fahrzeugs, insbesondere deren Kurvensteifigkeit und/oder Relaxationslänge RL und/oder Lateralsteifigkeit LS.

In addition, the following stored vehicle parameters are taken into account:

• - a steering and front axle geometry of the vehicle, in particular a scrub radius LRR, a spread S and a caster NL,
• - Characteristics of the tires of the vehicle, in particular their cornering stiffness and/or relaxation length RL and/or lateral stiffness LS.

The expected values LW _e , GR _e , QB _e are compared in a comparator 3 with measured values, in particular the steering angle LW and/or the yaw rate GR and/or the transverse acceleration QB. If the measured steering angle LW and/or the measured acceleration, for example the yaw rate GR and/or the lateral acceleration QB and their progression, deviate from the respective expected value LW _e , GR _e , QB _e , then it is concluded that a manual steering intervention ME by the driver is present . If this is the case, then the steer-by-brake function can be switched off.

In a steer-by-brake process, depending on the input variables brake pressure difference Δp on the front axle and speed v, as well as the parameters scrub radius LRR, spread S, caster NL, lateral stiffness LS and front axle load VAL, the output variables steering angle LW and those from the speed result v dependent accelerations yaw rate GR and lateral acceleration QB. This results in a curve curvature, a change in the measured lane position SL and a change in the measured lateral distances D to adjacent objects.

In the case of a manual steering intervention ME, depending on the input variables speed v and steering angle LW as well as the parameters wheelbase RS and self-steering gradient, the output variables curve curvature and the accelerations yaw rate GR and lateral acceleration QB dependent on the speed v result.

2 is a schematic view of an embodiment of the device 1 for detecting a manual steering intervention ME in a vehicle, for example in a commercial vehicle, a bus or a passenger car, in particular in a highly automated vehicle with a steer-by-brake function.

The device 1 comprises a state estimator 2 or observer, which, on the basis of measured vehicle state variables and known vehicle geometries and properties, in particular parameters and/or constants, calculates an expected value LW _e of a steering angle and expected values GR _e , QB _e during a steer-by-brake intervention for accelerations, in particular the expected value GR _e of a yaw rate and the expected value QB _e of a lateral acceleration, as well as a predicted lane position SL _p and predicted distances D _p to secondary objects are calculated.

• - die Bremsdruckdifferenz Δp, insbesondere an einer Vorderachse des Fahrzeugs, optional auch an einer Hinterachse,
• - die Geschwindigkeit v des Fahrzeugs,
• - ein Gewicht G oder eine Masse des Fahrzeugs und/oder deren Verteilung auf die Vorderachse und weitere Achsen des Fahrzeugs, insbesondere eine Vorderachslast VAL und optional weitere Achslasten.

The relevant vehicle state variables for the expected values of the steering angles LW _e and accelerations GR _e , QB _e are:

• - the brake pressure difference Δp, in particular on a front axle of the vehicle, optionally also on a rear axle,
• - the speed v of the vehicle,
• - A weight G or a mass of the vehicle and/or its distribution to the front axle and other axles of the vehicle, in particular a front axle load VAL and optionally other axle loads.

• - eine Lenk- und Vorderachsgeometrie des Fahrzeugs, insbesondere ein Lenkrollradius LRR, eine Spreizung S und ein Nachlauf NL, sowie eine Spur SP und ein Radstand RS,
• - Eigenschaften der Reifen des Fahrzeugs, insbesondere deren Kurvensteifigkeit und/oder Relaxationslänge RL und/oder Lateralsteifigkeit LS.

In addition, the following stored vehicle parameters are taken into account:

• - A steering and front axle geometry of the vehicle, in particular a scrub radius LRR, a spread S and a caster NL, as well as a track SP and a wheelbase RS,
• - Characteristics of the tires of the vehicle, in particular their cornering stiffness and/or relaxation length RL and/or lateral stiffness LS.

The expected values LW _e , GR _e , QB _e , the predicted track position SL _p and the predicted distances D _p to secondary objects are compared in a comparator 3 with corresponding measured values, in particular the steering angle LW, the yaw rate GR, the lateral acceleration QB, a track position SL and distances D compared to secondary objects in order to detect a manual steering intervention ME by the driver. An absolute value formation BW, a filtering F, a weighting and a test T for exceeding a threshold value are applied to the respective result of the comparison. The signals processed in this way are linked to one another in a linking unit 4 in order to determine an extent A of the manual steering intervention ME. Depending on this extent A, it can be decided whether the steer-by-brake function is switched off.

The state estimator 2 can be designed to model a steer-by-brake process using the input data mentioned. For this purpose, the state estimator 2 can be supplied with the measured values of steering angle LW, yaw rate GR, transverse acceleration QB, lane position SL and distances D to secondary objects as initial values.

The measured quantities can be filtered. The filtering F can be conventional or model-based (for example observer, Kalman filter or particle filter).

Reference List

1

Device for detecting a manual steering intervention

2

state estimator

3

comparator

4

linkage unit

A

extent

BW

absolute value formation

D

Distances to secondary objects

dp

predicted distances to secondary objects

f

filtering

G

Weight

GR

yaw rate

GRe

Expected yaw rate

LRR

scrub radius

LS

lateral stiffness

Lw

steering angle

LWe

Expected value of a steering angle

ME

manual steering intervention

NL

trailing

QB

lateral acceleration

QBe

Expected lateral acceleration

RL

relaxation length

RS

wheelbase

S

spread

SL

tracking

SLp

predicted lane position

SP

track

T

Test for exceeding a threshold

v

speed

VAL

front axle load

Δp

brake pressure difference

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was 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.

Patent Literature Cited

• EP 2448795 B1 [0003]

Claims (6)

Method for detecting a manual steering intervention (ME) in a vehicle with a steer-by-brake function, characterized in that in a state estimator (2) on the basis of measured vehicle state variables, including a brake pressure difference (Δp) on a front axle and a speed ( v), as well as known parameters of the vehicle, including scrub radius (LRR), kingpin (S), caster (NL), a relaxation length (RL) and/or lateral stiffness (LS) of the tires of the vehicle and a front axle load (VAL), at a Steer-by-brake intervention, an expected value (LW _e ) of a steering angle and expected values for a yaw rate (GR _e ) and a lateral acceleration (QB _e ) are calculated, with the expected values (LW _e , GR _e , QB _e ) being calculated with corresponding measured values Values of the steering angle (LW), the yaw rate (GR) and the lateral acceleration (QB) are compared, whereby if the measured values deviate from the expected values (LW _e , GR _e , QB _e ), it is concluded that a manual steering intervention (ME ) is present and the steer-by-brake function is switched off. procedure after claim 1 , characterized in that a brake pressure difference (Δp) on at least one rear axle is also taken into account as a measured vehicle state variable. procedure after claim 1 or 2 , characterized in that an axle load of at least one rear axle and/or a track (SP) and/or a wheelbase (RS) are/is taken into account as parameters. Method according to one of the preceding claims, characterized in that the state estimator (2) also calculates a predicted lane position (SL _p ) and predicted distances (D _p ) to secondary objects and these values are each calculated with measured values of the lane position (SL) and the distances (D) are compared to secondary objects in order to detect a manual steering intervention (ME). Method according to one of the preceding claims, characterized in that absolute value formation (BW), filtering (F), weighting and a test (T) for exceeding a threshold value are applied to the respective result of the comparison, the signals processed in this way being compared with one another be linked in order to determine an extent (A) of the manual steering intervention (ME), a decision being made as a function of this extent (A) as to whether the steer-by-brake function is switched off. Device (1) for detecting a manual steering intervention (ME) in a vehicle with a steer-by-brake function, characterized in that the device (1) has a state estimator (2) and for carrying out the method according to one of the preceding claims is configured.

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