WO2023094046A1 - Procédé de commande d'un système de direction pour un véhicule automobile, et système de direction pour un véhicule automobile pour la mise en œuvre du procédé - Google Patents

Procédé de commande d'un système de direction pour un véhicule automobile, et système de direction pour un véhicule automobile pour la mise en œuvre du procédé Download PDF

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Publication number
WO2023094046A1
WO2023094046A1 PCT/EP2022/076007 EP2022076007W WO2023094046A1 WO 2023094046 A1 WO2023094046 A1 WO 2023094046A1 EP 2022076007 W EP2022076007 W EP 2022076007W WO 2023094046 A1 WO2023094046 A1 WO 2023094046A1
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WO
WIPO (PCT)
Prior art keywords
value
input
steering
actual
driver
Prior art date
Application number
PCT/EP2022/076007
Other languages
German (de)
English (en)
Inventor
Alexander Sauter
Joerg Strecker
Original Assignee
Robert Bosch Gmbh
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Robert Bosch Gmbh filed Critical Robert Bosch Gmbh
Publication of WO2023094046A1 publication Critical patent/WO2023094046A1/fr

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
    • B62D—MOTOR VEHICLES; TRAILERS
    • B62D6/00—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits
    • B62D6/002—Arrangements for automatically controlling steering depending on driving conditions sensed and responded to, e.g. control circuits computing target steering angles for front or rear wheels

Definitions

  • the disclosure relates to a method for controlling a steering system for a motor vehicle and a steering system for a motor vehicle for performing the method.
  • Steering systems for motor vehicles in which there is no mechanical connection between the input setpoint that can be specified on an input device, in particular the steering handle, in particular the handle position, and the wheel position of the steered wheels are also known as steer-by-wire steering systems.
  • unintentional deviations in position can occur between the desired input value specified at the input device and an actual value of a steering actuator acting on the steerable wheels.
  • Such position deviations can occur in particular because the input device is actuated when the ignition is switched off.
  • a reduced performance of the steering actuator for example due to low battery voltage or increased temperatures, or a temporary blocking of the steering actuator, for example by a curb, can lead to position deviations.
  • Such position deviations can represent a potential hazard.
  • position deviations can therefore be relevant to safety.
  • the steering wheel angle is an important input variable in many vehicle assistance systems and in automated driving functions, so that such position deviations can lead to a loss of comfort and/or functionality.
  • a system and method for correcting a steering offset is known from DE 102015222 512 A1.
  • the present disclosure seeks to provide an improved steering system and method.
  • This object is achieved by a method for controlling a steering system having the features of claim 1 and a steering system having the features of claim 10.
  • a difference is understood here to mean a larger difference that has arisen and goes beyond smaller control differences that occur during normal operation. Larger differences of this kind occur in certain driving situations, such as the curb impressions described above. The dead zone takes these larger deviations into account.
  • the advantage of the dead zone is that in the case of non-safety-related deviations, which are system-related in regular operation occur, no functional interventions and thus reduction in the power of the steering actuator of the axle takes place.
  • the function only works outside the dead zone, where the offset that then occurs is classified as safety-relevant.
  • the dead zone defines a tolerated deviation between the input setpoint and the actual value. Provision can be made for the dead zone to have a constant or a variable value.
  • the value of the dead zone is determined as a function of an application situation of the steer-by-wire steering system.
  • An application situation includes, for example, a driver mode, i.e. a driver steers the vehicle, or an automated or partially automated ferry operation, a start-up phase of the system and/or transition phases between the application situations mentioned.
  • automated or partially automated ferry operations for example, no input target value is specified via the input device.
  • a steering wheel can make a different movement than steerable wheels, for example it can be held in one position, in particular in a zero position, or the steering movement of the wheels can only partially follow.
  • a dead zone can be selected to be very large, so that a very large deviation from the input target value and the actual value is tolerated, and no compensation function is calculated, or a compensation function is only calculated if there is a very large deviation.
  • compensation when changing between ferry companies can be advantageous.
  • the compensation variable is a constant variable when the input setpoint value is constant.
  • the compensation variable is changed only slowly or allows slow changes when the input setpoint is constant. So if the driver does not intend to change a direction of travel and therefore does not change the input setpoint, in this case there will only be a slow change in the control setpoint and thus the actual value and consequently only a slow change will result in vehicle movement.
  • the compensation variable is not a constant variable when the input target value is constant.
  • the non-constant variable is advantageously specified in such a way that the compensation variable is changed only slowly and/or slightly, so that the driver can still control it despite the changes in the compensation variable. For example, by the slow and / or low Changing the compensation variable ensures that the vehicle does not leave the lane uncontrollably.
  • the rate of change of the compensation variable can be specified as between 0 to 20 mm/s, in particular less than 10 mm/s, in particular less than 5 mm/s.
  • the rate of change can also be specified as a function of the operating parameters of the vehicle, for example vehicle speed, lateral acceleration, etc.
  • the compensation function is specified as a compensation speed and when the input setpoint changes in the direction of the actual value, the gradient of the actual value is smaller than the gradient of the input setpoint and when the input setpoint changes away from the actual value, the gradient of the actual value is greater than the gradient of the input setpoint.
  • the control setpoint is always changed via the function and the actual value follows the control setpoint.
  • the difference between the input target value and the actual value can be increased both for steering inputs that would lead to an increase in the difference between the input target value and the actual value without adjusting the actual value, and for steering inputs that would already increase without adjusting the actual value a decrease in the difference between the input setpoint and the actual value can be effectively reduced by changing the actual value either faster or slower than the input setpoint. For example, with a change in the nominal input value in the direction of the actual value, i.e.
  • the value of the gradient of the actual value can be between 10% and 90%, in particular between 50% and 80%, for example 75%, of the value of the gradient of the input setpoint.
  • the value of the gradient of the actual value is between 110% and 200%, for example 150% of the value of the gradient of the input target.
  • the compensation function is specified as a compensation speed as a function of at least one operating variable of the motor vehicle.
  • the dependency can include a linear or non-linear relationship, for example.
  • Operating variables are, for example, a steering speed, a driving speed or a lateral acceleration.
  • a maximum and/or a minimum value is specified for the gradient of the actual value.
  • a minimum and/or a maximum speed for reducing a position deviation can be specified.
  • the gradient is limited to a maximum value, taking into account the current maximum dynamics of the steering actuator. This maximum dynamic can be subject to changes due to the current performance of the steering actuator due to external influences, such as the vehicle electrical system, steering dynamics or external axle forces.
  • FIG. 1 shows a schematic illustration of a flow chart of a method for controlling a steering system
  • FIG. 2 shows a schematic representation for calculating a compensation variable in a steering system
  • FIG. 3 shows a schematic representation for calculating a compensation function in a steering system
  • FIG. 6 shows a schematic representation of a vehicle.
  • the steer-by-wire steering system includes an electronic control device for controlling a steering actuator acting on steerable wheels by means of a control target value as a function of a target input value that can be specified via an input device, in particular a target steering angle that can be set by a driver or a target steering angle set by a driver adjustable target rack position.
  • the method 100 comprises the following steps: a step 110 for providing an actual value of the steering actuator and providing the input setpoint value that can be specified via the input device, a step 120 for determining a difference between an actual value of the steering actuator, in particular an actual steering angle or an actual rack position, and the input setpoint; a step 130 for providing the control setpoint based on the input setpoint and a compensation variable, the compensation variable having a dead zone and a compensation function for reducing the difference between the actual value of the steering actuator and the input setpoint.
  • the calculation of the compensation variable in particular the dead zone and the compensation function, is described below with reference to FIGS. 2 and 3, using the example of a rack position.
  • the calculation of the compensation variable and the control of the steering system can also be based on a steering angle, in particular a steering wheel angle or wheel steering angle.
  • the control target value posRack_Soll for controlling the steering actuator is provided based on the input target value posRack_Soll(driver) and a compensation variable posRack_Hold.
  • the compensation variable posRack_Hold includes a dead zone and a compensation function.
  • the compensation function reduces a dynamic offset. According to the compensation function, the offset is reduced slowly, in particular not abruptly or suddenly, and in a controllable manner.
  • the difference between the input target value posRack_Soll(driver) and the actual value, the current actual rack position posRACK_SRA, is calculated.
  • the sign is then multiplied by the difference to get the direction.
  • the absolute value of the difference is now provided with a dead zone.
  • the dead zone is selected, for example, as a rack position deviation that can be corrected with maximum dynamics of the steering actuator without the driver losing control.
  • the constant value of 5 mm is used here as an example.
  • the value of the dead zone can also be selected depending on the steering speed of the driver, the vehicle speed and other values such as lateral acceleration, as well as on the use case of the function.
  • the difference now obtained is modified by a gradient limitation. In this case, increasing values, ie the build-up of a difference between the input target value posRack_Soll(driver) and the actual value posRACK_SRA, are treated without limitation.
  • the gradient should be selected in such a way that the reduction can be controlled by the driver or controllable behavior sets in, see RL_Limit_Falling.
  • the steering speed of the driver is calculated using the rack position as an example.
  • the sign of the speed is multiplied by the sign of the difference between the input target value posRack_Soll(driver) and the actual value, the current actual rack position posRACK_SRA. In this way, the following two cases are distinguished:
  • the driver steers in the same direction in which the difference has already occurred. For example, left is considered a positive direction. In this case, there has already been a difference to the left and the driver steers further to the left.
  • the input setpoint is changed away from the actual value. This means that without adjusting the actual value, this steering input would lead to an increase in the difference between the input target value and the actual value.
  • the difference is reduced if the gradient of the actual value is greater than the gradient of the input setpoint. The actual value is therefore changed faster than the input setpoint.
  • the driver does not continue to steer in the direction in which the difference has already occurred. The driver therefore no longer steers to the left, but in the opposite direction, i.e. to the right.
  • the input setpoint is therefore changed in the direction of the actual value. This means that this steering input would already lead to a reduction in the difference between the desired input value and the actual value without the actual value being adjusted. In the present case, however, the difference is further reduced in that the gradient of the actual value is selected smaller than the gradient of the input setpoint. The actual value is therefore changed more slowly than the input setpoint. This procedure is advantageous so that the reduction in the difference appears to be controllable for the driver. With a steering input, the driver expects an adjustment of the steering direction of the vehicle. It is therefore provided that the steering intervention brought about by activation of the steering actuator to compensate for the position deviation does not lead to any adjustment of the steered wheels contrary to the steering direction intended by the driver.
  • the compensation variable is reduced on the basis of the steering speed.
  • a linear dependency on the steering speed is provided using the constant values 0.5 or 0.25.
  • a non-linear dependency on the steering speed of the driver, the vehicle speed and/or other values such as the lateral acceleration is also possible.
  • the gradient can be limited to a maximum value, taking into account the maximum dynamics of the steering actuator and/or a limitation to a minimum value.
  • the vehicle reaction i.e. the change in the actual value
  • the vehicle reaction is 50% faster than the steering speed.
  • the vehicle reaction i.e. the change in the actual value, is 25% less than the steering speed.
  • FIG. 4 shows different variables of the steering system over time for an exemplary application.
  • the x-axis represents time t in seconds
  • the y-axes are rack positions in millimeters.
  • Absolute values of the “rack position” variable are shown over time in the top illustration of FIG.
  • the dashed line represents the steering rack position according to the driver's request, also the input setpoint
  • the solid line represents the actual rack position, also the actual value.
  • the dashed line represents the difference between the steering rack position as requested by the driver and the actual steering rack position
  • the solid line represents the output of the compensation function
  • the actual rack position changes up to 10 mm according to the rack position commanded by the driver.
  • a "dead zone" of 5 mm is provided, i.e. a deviation between the input setpoint and the actual value of 5 mm is tolerated.
  • Such a limitation arises, for example, from environmental influences, such as the wheels locking on a curb.
  • the driver does not change the specified rack position.
  • the actual position is also not changed in these time periods.
  • the compensation function is kept constant. Only the exemplary tolerable change of 5mm at 4 seconds.
  • a vehicle reaction ie a change in the activation of the steering actuator acting on the wheels, only takes place if the driver also steers, ie if there is a change in the setpoint input value. Accordingly, the difference can only be reduced if the driver also steers.
  • the driver begins to change the specified rack position again.
  • the gradient of the rack position is 20 mm/s according to the driver's request.
  • the gradient of the actual rack position ie the actual position
  • the gradient of the actual rack position is 30 mm/s
  • the actual position thus approaches the rack position according to the driver's request, with the gradient of the actual position being 50% greater than the gradient of the rack position according to the driver's request according to the illustrated embodiment.
  • the driver begins to change the specified rack position again.
  • the gradient of the rack position according to the driver's request is -20 mm/s.
  • the gradient of the actual rack position i.e. the actual position
  • the gradient of the actual position is 25% smaller than the gradient of the rack position according to the driver's request.
  • time profiles of the variables already described with reference to FIG. 3 are shown in FIG. 5 for the exemplary application, with no calculation of the compensation function taking place according to the variables shown in FIG. setpoint is made according to the compensation function.
  • this limitation no longer exists. This means that the rack can move freely again at this point in time.
  • the elimination of the deviation from the rack position according to the driver's request and the actual position can lead to an abrupt change in direction of the vehicle, which the driver may only be able to control to a limited extent. This conditional controllability can represent a significant loss of comfort and control.
  • FIG. 6 shows a schematic representation of a vehicle 600 that includes a device 602 for influencing the driving behavior of vehicle 600 according to the described method.
  • the device 602 includes, for example, a computing device or multiple computing devices.
  • the device 602 comprises a control system according to FIGS. 2 and 3, or at least a part thereof.
  • the vehicle 600 includes at least one steering actuator 604.
  • the steering actuator 604 is the front-axle steering actuator.
  • the steering adjuster In the example, 604 represents a first actuator with which the driving behavior of vehicle 600 can be influenced as described.
  • the vehicle 600 includes two rear wheels 606 and two front wheels 608.
  • the rear wheels 606 are not steerable in the example.
  • the front wheels 608 can be steered by the steering actuator 604 as described.
  • the first actuator is designed in the example to steer at least one wheel of the front axle depending on the overlap angle to the driver for the front axle.
  • the rear wheels 606 can also be steered by the rear-axle steering actuator.
  • the method can also be used for individual wheels if the steering controller 604 is not, as shown, a central controller that connects both steered wheels, but rather two separate controllers that act independently on the left and right wheels.
  • vehicle 600 includes a yaw rate sensor 614 which is designed to detect the yaw rate of vehicle 600 . At least one other sensor can also be provided, with which a variable is detected from which the yaw rate of vehicle 600 can be calculated from a model.
  • the lateral acceleration can also be taken into account.
  • the vehicle advantageously includes appropriate sensors for detecting the lateral acceleration.
  • Vehicle 600 includes at least one steering angle sensor 616 which is designed to detect the steering angle set by the driver of vehicle 600 .
  • vehicle 600 includes additional sensors or detection devices that are suitable, for example, for detecting a rack position, a steering speed, or a vehicle speed. In addition to an actual steering angle sensor, this angle can also be calculated on the basis of internal variables in the input device.
  • these sensors are connected to the device 602 via data lines represented by a solid line. The data lines can be designed as part of a controller area network, CAN, bus system.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Steering Control In Accordance With Driving Conditions (AREA)

Abstract

L'invention se rapporte à un procédé (100) destiné à commander un système de direction à direction par câble et un système de direction à direction par câble pour un véhicule automobile (600) doté d'un dispositif de commande électronique (602) destiné à actionner un actionneur de direction (604), qui agit sur des roues directrices, au moyen d'une valeur de consigne de commande dépendant d'une valeur de consigne d'entrée pouvant être prédéfinie au moyen d'un dispositif d'entrée, le procédé comprenant les étapes suivantes : la fourniture (110) d'une valeur réelle de l'actionneur de direction et la fourniture de la valeur de consigne d'entrée pouvant être prédéfinie au moyen du dispositif d'entrée ; la détermination (120) d'une différence entre une valeur réelle de l'actionneur de direction ; la fourniture (140) de la valeur de consigne de commande sur la base de la valeur de consigne d'entrée et d'une variable de compensation, la variable de compensation comprenant une zone morte et une fonction de compensation permettant de réduire la différence entre la valeur réelle de l'actionneur de direction et la valeur de consigne d'entrée.
PCT/EP2022/076007 2021-11-29 2022-09-20 Procédé de commande d'un système de direction pour un véhicule automobile, et système de direction pour un véhicule automobile pour la mise en œuvre du procédé WO2023094046A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102021213389.4A DE102021213389A1 (de) 2021-11-29 2021-11-29 Verfahren zum Steuern eines Lenksystems für ein Kraftfahrzeug und Lenksystem für ein Kraftfahrzeug zum Durchführen des Verfahrens
DE102021213389.4 2021-11-29

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WO2023094046A1 true WO2023094046A1 (fr) 2023-06-01

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PCT/EP2022/076007 WO2023094046A1 (fr) 2021-11-29 2022-09-20 Procédé de commande d'un système de direction pour un véhicule automobile, et système de direction pour un véhicule automobile pour la mise en œuvre du procédé

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DE (1) DE102021213389A1 (fr)
WO (1) WO2023094046A1 (fr)

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Publication number Priority date Publication date Assignee Title
DE102022202482A1 (de) 2022-03-14 2023-09-14 Robert Bosch Gesellschaft mit beschränkter Haftung Verfahren zum Betrieb eines Lenksystems eines Fahrzeugs

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015222512A1 (de) 2014-12-02 2016-06-02 Ford Global Technologies, Llc Systeme und Verfahren zum Korrigieren von Lenkversätzen
DE102019202003A1 (de) * 2019-02-14 2020-08-20 Thyssenkrupp Ag Verfahren zur Steuerung eines Lenksystems für ein Kraftfahrzeug und Lenksystem für ein Kraftfahrzeug zur Durchführung des Verfahrens

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10302559A1 (de) 2003-01-22 2004-09-09 Daimlerchrysler Ag Verfahren zur Synchronisation von Lenkhandhabe und gelenkten Fahrzeugrädern
DE102014200100B4 (de) 2013-01-15 2018-04-05 Ford Global Technologies, Llc Lenkwinkelfehlerkorrektur

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102015222512A1 (de) 2014-12-02 2016-06-02 Ford Global Technologies, Llc Systeme und Verfahren zum Korrigieren von Lenkversätzen
DE102019202003A1 (de) * 2019-02-14 2020-08-20 Thyssenkrupp Ag Verfahren zur Steuerung eines Lenksystems für ein Kraftfahrzeug und Lenksystem für ein Kraftfahrzeug zur Durchführung des Verfahrens

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