WO2021139998A1 - Procédé pour freiner un véhicule - Google Patents

Procédé pour freiner un véhicule Download PDF

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Publication number
WO2021139998A1
WO2021139998A1 PCT/EP2020/086821 EP2020086821W WO2021139998A1 WO 2021139998 A1 WO2021139998 A1 WO 2021139998A1 EP 2020086821 W EP2020086821 W EP 2020086821W WO 2021139998 A1 WO2021139998 A1 WO 2021139998A1
Authority
WO
WIPO (PCT)
Prior art keywords
braking
braking force
vehicle
force
duration
Prior art date
Application number
PCT/EP2020/086821
Other languages
German (de)
English (en)
Inventor
Raphael Oliveira
Anurag Mehta
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 WO2021139998A1 publication Critical patent/WO2021139998A1/fr

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/172—Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T7/00—Brake-action initiating means
    • B60T7/12—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger
    • B60T7/22—Brake-action initiating means for automatic initiation; for initiation not subject to will of driver or passenger initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle, or by means of contactless obstacle detectors mounted on the vehicle
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T2230/00—Monitoring, detecting special vehicle behaviour; Counteracting thereof
    • B60T2230/04—Jerk, soft-stop; Anti-jerk, reduction of pitch or nose-dive when braking

Definitions

  • the invention relates to a method for braking a vehicle.
  • the invention also relates to a control device, a computer program product and a computer-readable medium for carrying out the method.
  • the invention also relates to a brake system for a vehicle.
  • a jolt or audible or perceptible vibrations also known as NVH (noise, vibration, harshness).
  • US Pat. No. 9,358,962 B2 describes a method for stopping a motor vehicle which has an electronic environment control device for evaluating the data of one or more environment sensors and an electronic brake control device for controlling a brake system, which exchange information and / or instructions via a data connection.
  • the method comprises the following steps: acquiring a distance to a vehicle traveling ahead; Determining the driving speed of the motor vehicle; Regulating the distance to the vehicle in front by the environment control device if the vehicle speed exceeds a transfer threshold value; and stopping the motor vehicle by the brake control device if the driving speed is less than or equal to the transfer threshold value.
  • the environment control device specifies a target route for the brake control device, after which the motor vehicle should stop.
  • US 2017/0205831 A1 describes a stopping distance system with which a stopping distance of a vehicle is received.
  • a train that has a multitude of acceleration segments is displayed according to the stopping distance with a plotter.
  • a vehicle brake and / or a vehicle drive are adjusted based on the trajectory to stop the vehicle.
  • the acceleration segments include at least two of the following driving situations: an upward movement, a slowdown, a downward movement, and a final deceleration.
  • WO 2008/012160 A1 describes a device for speed and stopping control in motor vehicles with a sensor system for locating a vehicle in front, a slave controller for controlling the distance between the vehicle in front and the vehicle in front while driving and a stopping controller that brakes the vehicle in front, when it is detected that the vehicle in front is stopping or will stop.
  • a rolling phase controller is implemented in the stopping controller, which keeps the vehicle's speed approximately constant during a rolling phase shortly before the vehicle comes to a standstill.
  • Embodiments of the present invention advantageously make it possible to avoid unpleasant jolts, noises or vibrations when a vehicle is brought to a standstill, for example with the aid of a driver assistance function.
  • a first aspect of the invention relates to a method for braking a vehicle, the vehicle having a brake actuator for generating a braking force for braking the vehicle and a control unit for controlling the brake actuator.
  • the method comprises the following steps, which can in particular be carried out in the specified order: Receiving a braking request in the control device; Determining a braking duration during which the braking force is to be generated to stop the vehicle based on the braking request; Determining a time profile of a braking force gradient of the braking force based on the braking duration, the braking force gradient being greater in magnitude at the end of the braking duration than at the beginning of the braking duration; and controlling the brake actuator in order to generate the braking force in accordance with the course of the braking force gradient.
  • a rigidity in the braking force build-up can vary depending on a braking force already present in the brake system, for example a hydraulic pressure. If the braking force in the braking system increases, the rigidity also increases. This means that a brake actuator, such as a pump or an electric motor, must first run at increased speed in order to increase the braking force. Since the rigidity increases accordingly, the brake actuator can run at a lower speed for a further increase in braking force. With the method described here and below, it can be achieved that the brake actuator runs at a relatively low speed during the phase of the increase in braking force, as a result of which vibrations during the braking process are reduced.
  • a dynamic braking force gradient is used instead of a constant braking force gradient.
  • the braking force that is required to bring the vehicle to a standstill and to keep it at a standstill can be built up based on a time-dependent function such as a polynomial function or some other function whose function value increases over time.
  • a brake actuator can, for example, be a pump for building up hydraulic or pneumatic pressure in a brake system of the vehicle.
  • the braking request can, for example, be output by a driver assistance function of the vehicle when the driver assistance function has recognized that the vehicle should be braked.
  • the braking request can be output taking into account a driver's request, for example depending on an accelerator or brake pedal position.
  • the driver assistance function can, for example, be an electronic brake management system of the vehicle or a component thereof. It is useful if the braking time is shorter than 1 s.
  • a braking force gradient can be understood to mean a change, in particular an increase in the braking force per unit of time.
  • the course of the braking force gradient can be specified by any continuous function that outputs output values that increase linearly or non-linearly with increasing input values, in particular using a polynomial of the second or higher degree.
  • the braking force gradient can also run exponentially.
  • the braking force gradient can be flatter at the beginning of the braking period than at the end of the braking period. In this way, on the one hand, vibrations, such as those caused by a fast-running pump in the brake system, can be reduced.
  • a relatively large braking force can be built up by the end of the braking period, which makes it possible to keep the vehicle safely at a standstill; H. to prevent the vehicle from jerking after stopping.
  • a second aspect of the invention relates to a control device which is configured to carry out the method as described above and below.
  • Features of this method can also be features of the control unit and vice versa.
  • a third aspect of the invention relates to a brake system which is configured to carry out the method as described above and below.
  • Features of this method can also be features of the braking system and vice versa.
  • the computer readable medium can be volatile or non-volatile data storage.
  • the computer-readable medium can be a hard disk, a USB storage device, a RAM, ROM, EPROM or flash memory.
  • the computer readable medium can also be a downloadable program code
  • Data communication network such as the Internet or a data cloud.
  • Features of the method, as described above and below, can also be features of the computer program and / or the computer-readable medium, and vice versa.
  • the course of the braking force gradient can be defined by a polynomial of the second or higher degree.
  • the braking force gradient can thus be determined with little computational effort.
  • the braking force gradient can always increase in amount during the braking period. This has the effect that the braking force increases relatively steeply towards the end of the braking period. As a result, the vehicle can be brought to a standstill without jolts and safely kept at a standstill.
  • the braking duration can be determined based on a target braking force, an actual braking force and an actual driving force.
  • a target braking force can be understood to mean a braking force that should be present in the braking system at the end of the braking period.
  • An actual braking force can be understood to mean a braking force that is present in the braking system at the beginning of the braking period.
  • An actual drive force can be understood to mean a force generated by a drive train of the vehicle at the beginning of the braking period.
  • the actual driving force and the braking force can be directed in the same or opposite directions depending on the driving situation of the vehicle, for example depending on the inclination of the vehicle. As a result, the braking duration can be estimated with sufficient accuracy.
  • a braking force ratio can be calculated based on the actual braking force and the target braking force. Furthermore, a driving force ratio can be calculated based on the actual driving force and the target braking force.
  • the reference braking duration can vary depending on a driving situation of the vehicle, for example.
  • the braking force ratio can be calculated taking into account a braking force weighting factor with:.
  • the braking force weighting factor can have values assume from 0 to 1. As a result, an effect of the braking force ratio on the braking duration can be influenced.
  • the driving force ratio can be calculated taking into account a driving force weighting factor with: For example, the
  • Driving force weighting factor can take values from 0 to 1. As a result, an effect of the driving force ratio on the braking duration can be influenced.
  • the reference braking duration can indicate a braking duration during which the braking force is to be generated in order to stop the vehicle when the actual braking force is zero and the actual driving force corresponds to a driving force when the vehicle is idling.
  • the course of the braking force gradient can be determined as a function of an earlier course of the braking force, for example the setpoint braking force or a gradient with respect to the setpoint braking force.
  • Fig. 1 shows a vehicle with a braking system according to an embodiment of the invention.
  • FIG. 2 shows a diagram to illustrate a time profile of a braking force gradient, determined by a control device from FIG. 1.
  • FIG. 3 shows a flow chart of a method according to an exemplary embodiment of the invention.
  • the figures are only schematic and not true to scale.
  • the same reference symbols denote the same or equivalent features.
  • the braking system 102 is designed to brake the vehicle 100.
  • the brake system 102 comprises a brake actuator 104, for example in the form of a pump, which is designed to apply a braking force F B to the brakes 106 of the vehicle 100, for example in the form of hydraulic or pneumatic pressure, whereby the vehicle 100 is braked.
  • the brake system 102 comprises a control unit 108 which is configured to control the brake actuator 104 in a suitable manner.
  • control unit 108 is configured to receive a braking request 112 from a driver assistance system 110 of the vehicle 100 or a component thereof, for example a brake assistant for the (partially) automated execution of a braking or parking maneuver, which indicates that the vehicle 100 has stopped and to convert the brake request 112 into a corresponding control signal 114 for controlling the brake actuator 104.
  • the control device 108 can be part of an on-board computer of the vehicle 100, for example.
  • control unit 108 is configured to generate the braking force F B with a braking force gradient dF B , which increases steadily in terms of amount during a braking period.
  • FIG. 2 shows a diagram 200 with a possible profile 202 of the braking force gradient dF B during the braking duration t B.
  • the braking force gradient dF B is defined here by a function G (t) and, starting from a negative initial value, falls initially flat, then comparatively steeply into the negative , in particular towards the end of the braking period t B.
  • G (t) a function
  • G (t) the braking force gradient
  • setpoint setpoint
  • the target braking force F B, target is illustrated by an area between a horizontal line of the target gradient dF B, target and a time axis of the diagram 200.
  • the target braking force F B, Soll can be distributed in a suitable manner over the braking duration t B , in particular it can be distributed such that the target braking force F B, Soll is only distributed towards the end of the braking duration t B , ie shortly before the vehicle 100 comes to a standstill, increases in amount very sharply, that is, it goes negative, while it increases only relatively weakly in amount at the beginning of the braking duration t B.
  • FIG. 3 shows an exemplary sequence of a method 300 for braking the vehicle 100.
  • the method 300 can be carried out by the control device 108 from FIG. 1.
  • the method 300 begins with a step 310, in which the braking request 112 is received in the control unit 108. Based on the braking request 112, the control unit 108 determines the braking duration t B that is required in order to build up a braking force F B sufficient to stop the vehicle 100.
  • Driving force weighting factor C A a driving force ratio R A is calculated, for example using the following equations:
  • R B and R A are limited to a maximum of 1 and a minimum of 0, respectively. Furthermore, R A is only calculated when the vehicle 100 is traveling uphill, since here the driving force can counteract the downhill force to a certain extent.
  • the constants C B and C A influence the effect of the ratios on the braking duration t B , ie on the duration of the braking force build-up, and can each assume values from 0 to 1.
  • the braking force F B can be built up quickly enough to reduce undesired vehicle movements.
  • the braking force F B can be built up slowly enough to increase the vibrations caused by the brake actuator 104 reduce.
  • a step 340 the braking force ratio R B and the driving force ratio R A are offset against a reference duration t Ref in order to obtain the braking duration t B.
  • the reference duration t Ref can, for example, indicate a duration during which the braking force F B is to be built up when the actual braking force F B, Ist is at least approximately zero and the actual driving force F A, Ist is at least approximately with a minimum driving force when idling of the vehicle 100 matches.
  • a suitable increase in the braking force gradient dF B is determined for the calculated braking duration t B with the aid of the function G (t).
  • the brake actuator 104 is activated in accordance with the increase in the braking force gradient dF B , so that the vehicle 100 is brought to a standstill and kept at a standstill at the end of the braking period t B without unpleasant jolts, vibrations or noises.
  • the braking force gradient dF B can be kept relatively low during a braking operation between an estimated stopping time at which the vehicle 100 stops and a time approximately 0.3 s to 0.5 s before the stopping time and then increased again in terms of amount. This makes it possible to ensure that sufficient braking force F B is built up at an early stage and undesired vehicle movements are avoided after the vehicle 100 has been brought to a standstill.
  • a continuous increase in the braking force gradient dF B can be calculated using an nth order polynomial with time t as the input value and a varying braking force gradient dF B as the output value.
  • a braking force can thus be built up shortly before the vehicle 100 comes to a standstill with a comparatively low braking force gradient dF B , which promotes pleasant, jerk-free braking behavior.
  • the build-up of braking force after the estimated stopping time can then take place with a braking force gradient dF B which is greater in magnitude.
  • dF B a braking force gradient
  • the braking force ⁇ F B to be built up can be calculated with:

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  • Engineering & Computer Science (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Regulating Braking Force (AREA)

Abstract

La présente invention concerne un procédé (300) permettant de freiner un véhicule (100), ledit véhicule (100) présentant un actionneur de frein (104) destiné à produire une force de freinage (F B ) pour freiner le véhicule (100) et un appareil de commande (108) destiné à assurer la commande de l'actionneur de frein (104). Le procédé (300) comprend les étapes suivantes : Recevoir (310) une demande de freinage (112) dans l'appareil de commande (108) ; déterminer (320, 330, 340) une durée de freinage (t B ), au cours de laquelle la force de freinage (F B ) doit être produite, de manière à arrêter le véhicule (100), sur la base de la demande de freinage (112) ; déterminer (350) une courbe temporelle (202) d'un gradient de force de freinage (dF B ) de la force de freinage (F B ) sur la base de la durée de freinage (t B ), le gradient de force de freinage (dF B ) étant supérieur, à la fin de la durée de freinage (tB), à celui au début de la durée de freinage (t B ) et activer l'actionneur de frein (104), de manière à produire la force de freinage (F B ) conformément à la courbe (202) du gradient de force de freinage (dF B ).
PCT/EP2020/086821 2020-01-09 2020-12-17 Procédé pour freiner un véhicule WO2021139998A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE102020200178.2A DE102020200178A1 (de) 2020-01-09 2020-01-09 Verfahren zum Bremsen eines Fahrzeugs
DE102020200178.2 2020-01-09

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Publication Number Publication Date
WO2021139998A1 true WO2021139998A1 (fr) 2021-07-15

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WO (1) WO2021139998A1 (fr)

Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0823360A2 (fr) * 1996-08-09 1998-02-11 Denso Corporation Système de freinage pour véhicule
WO2008012160A1 (fr) 2006-07-25 2008-01-31 Robert Bosch Gmbh Dispositif de régulation de la vitesse et de l'arrêt dans des véhicules automobiles
US9358962B2 (en) 2011-08-03 2016-06-07 Continental Teves Ag & Co. Ohg Method and system for adaptively controlling distance and speed and for stopping a motor vehicle, and a motor vehicle which works with same
US20170205831A1 (en) 2016-01-19 2017-07-20 Ford Global Technologies, Llc System for distance to stop
WO2018177785A1 (fr) * 2017-03-28 2018-10-04 Volkswagen Aktiengesellschaft Procédé de compensation d'une faible dynamique d'actionneur d'un frein mécanique d'un véhicule automobile et dispositif de commande
WO2018177786A1 (fr) * 2017-03-28 2018-10-04 Volkswagen Aktiengesellschaft Procédé permettant de faire fonctionner un dispositif de commande pour un système de freinage d'un véhicule automobile ainsi que dispositif de commande et véhicule automobile

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0823360A2 (fr) * 1996-08-09 1998-02-11 Denso Corporation Système de freinage pour véhicule
WO2008012160A1 (fr) 2006-07-25 2008-01-31 Robert Bosch Gmbh Dispositif de régulation de la vitesse et de l'arrêt dans des véhicules automobiles
US9358962B2 (en) 2011-08-03 2016-06-07 Continental Teves Ag & Co. Ohg Method and system for adaptively controlling distance and speed and for stopping a motor vehicle, and a motor vehicle which works with same
US20170205831A1 (en) 2016-01-19 2017-07-20 Ford Global Technologies, Llc System for distance to stop
WO2018177785A1 (fr) * 2017-03-28 2018-10-04 Volkswagen Aktiengesellschaft Procédé de compensation d'une faible dynamique d'actionneur d'un frein mécanique d'un véhicule automobile et dispositif de commande
WO2018177786A1 (fr) * 2017-03-28 2018-10-04 Volkswagen Aktiengesellschaft Procédé permettant de faire fonctionner un dispositif de commande pour un système de freinage d'un véhicule automobile ainsi que dispositif de commande et véhicule automobile

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