GB2474506A - Adaptive brake assist system - Google Patents

Adaptive brake assist system Download PDF

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Publication number
GB2474506A
GB2474506A GB0918231A GB0918231A GB2474506A GB 2474506 A GB2474506 A GB 2474506A GB 0918231 A GB0918231 A GB 0918231A GB 0918231 A GB0918231 A GB 0918231A GB 2474506 A GB2474506 A GB 2474506A
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United Kingdom
Prior art keywords
brake
pedal
applied force
force
vehicle
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Granted
Application number
GB0918231A
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GB0918231D0 (en
GB2474506B (en
Inventor
Nikolaos Gkikas
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Individual
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Individual
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Priority to GB0918231.2A priority Critical patent/GB2474506B/en
Publication of GB0918231D0 publication Critical patent/GB0918231D0/en
Publication of GB2474506A publication Critical patent/GB2474506A/en
Application granted granted Critical
Publication of GB2474506B publication Critical patent/GB2474506B/en
Expired - Fee Related legal-status Critical Current
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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
    • B60T7/00—Brake-action initiating means
    • B60T7/02—Brake-action initiating means for personal initiation
    • B60T7/04—Brake-action initiating means for personal initiation foot actuated
    • B60T7/042—Brake-action initiating means for personal initiation foot actuated by electrical means, e.g. using travel or force sensors
    • 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
    • B60T8/32—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration
    • B60T8/321—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force responsive to a speed condition, e.g. acceleration or deceleration deceleration
    • B60T8/3255—Systems in which the braking action is dependent on brake pedal data
    • B60T8/3275—Systems with a braking assistant function, i.e. automatic full braking initiation in dependence of brake pedal velocity
    • 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
    • B60T2201/00—Particular use of vehicle brake systems; Special systems using also the brakes; Special software modules within the brake system controller
    • B60T2201/03—Brake assistants

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

Abstract

A vehicle has a controller with a threshold brake-pedal applied force that triggers an emergency (maximum) braking torque request and an algorithm for continuously updating the threshold according to the previous history of braking events. An adaptive brake assist system (ABAS) includes force sensors connected to a brake pedal for detecting the amount of force applied on brake pedal and an algorithm for adapting the brake-pedal applied force required for a maximum braking torque request to the previous braking inputs by the operator. The method may only be used after a minimuin number of braking events have occurred.

Description

ADAPTIVE BRAKE ASSIST SYSTEM CONTROL APPARATUS
AND METHOD
TECHNICAL FIELD
(001) The present invention relates to an adaptive control method and apparatus for a brake assist system (BAS) having a brake pedal applied force sensor, the method and the apparatus for continuously adapting the trigger for augmenting driver braking in emergency conditions.
BACKGROUND OF INVENTION
(002) Conventional automotive vehicles typically include a mechanical brake system that is facilitated by hydraulics and servo-mechanisms. The brake pedal is connected to a lever and the depression of the brake pedal by the driver actuates a wheel-braking mechanism, such as a drum-brake or a disc-brake. The result is the negative acceleration of the vehicle, which may or may not result to a stop. The achieved deceleration is approximately proportional to the force applied and the resulted displacement of the pedal.
(003) Modern automotive vehicles employ electronic modules to control the transmission of brake torque to the wheels. Such modules can be part of the typical mechanical-hydraulic system or consist a complete braking system, in the case of electric or hybrid vehicles in particular. The electronic components are in some cases specified in a way that when the force applied on the brake pedal exceeds a certain threshold, the input is augmented and the maximum brake torque is applied on the wheels instead of the brake torque proportional to the force applied on the brake pedal.
(004) By way of contrast, variation is a characteristic both of and within human operators.
Operators inputs to the brake pedal during both normal and emergency braking vary from operator to operator. One operator's force input, when it is urgent to stop the vehicle, can be similar to another operator's typical force input. Also, the same driver can have variable inputs under similar circumstances during the day. Therefore, it is naturally impossible to accommodate every emergency braking input with a constant threshold for communication of a maximum brake torque request. To overcome this, the present invention proposes a BAS adaptive to the previous braking inputs of the operator.
SUMMARY OF INVENTION
(005) A vehicle is provided having a brake pedal for the operator to communicate the braking request to the vehicle, a sensor for detecting the brake-pedal applied force and a braking system configured to slow or stop the vehicle in proportion to the braking request by the operator. The brake system includes a controller that activates a maximum brake torque request when the instantaneous threshold is exceeded and having an algorithm for determining this trigger according to the previous history of brake-pedal inputs.
(006) On one aspect of the invention, the average pedal-force of all inputs that exceed 50N is calculated.
(007) On another aspect of the invention, a method is provided for adapting the amount of pedal-force required for the controller to employ the maximum brake torque, hereinafter named for simplicity trigger-force.
(008) On another aspect of the invention, the controller employees the maximum possible brake torque if a force input to the brake pedal has equaled or exceeded the concurrent trigger-force.
(009) On another aspect of the invention, if the pedal force does not exceed the concurrent threshold the controller employees brake torque proportionate to the pedal-force applied by the operator.
(010) On another aspect of the invention, an adaptive brake assist system (ABAS) is provided for a vehicle having a depressable brake pedal with a detectable apply-force, including a force-sensor operatively connected to the brake pedal for determining a force-based braking torque request. The ABAS controller has an algorithni configured to adapt the threshold for maximum brake torque request.
(011) On another aspect of the invention, the controller is configured to continuously calculate the average of all pedal force-inputs exceeding SON.
(012) On another aspect of the invention, the controller is operable for calculating the instantaneous trigger for a maximum brake torque request,based on the concurrent average pedal-force input.
(013) The features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
(014) Figure 1 is schematic representation of a vehicle chassis having a controller with an adaptive brake assist algorithm as per the invention; (015) Figure 2 is a flowchart describing the adaptive brake assist algorithm of the invention.
(016) Figure 3 is a graphic illustration of the adaptive behaviour of trigger-force (Tr) according to the look-up table 18 of the controller 10 of the invention.
DESCRIPTION OF THE PREFFERED EMBODIMENTS
(017) Referring to the drawings wherein like reference numbers correspond to like or similar components throughout the figures, there is shown in figure 1 a vehicle 50 having a plurality of wheels 51, an electronic braking system control unit or controller 10, and an engine 52 that is connectable to a transmission 53 having a rotatable output member 14. Vehicle 50 may be any vehicle utilising an electronic brake system controller 10 as described herein.
(01 8) Controller 10 is operable for detecting a brake-pedal application and the amount of the force applied on the brake pedal 17 using a brake pedal sensor 16 connected thereto. Controller 10 is configured to calculate, select or otherwise determine a corresponding braking request (B() in response to the detected and recorded measurements or readings. Controller 10 then communicates the braking request (B) to a braking mechanism to slow down or stop the vehicle 50. The braking request (B(') is transmitted across one or more command signal transmission channels or lines 55 to the braking units 13 and/or output member 14, where the braking request (B(.) can act to oppose the torque of each of the braking units 13 and/or output member 14.
(019) Output member 14 may be driveably connected to a rear differential 54, which is configured to distribute torque to rear drive axle 56. Alternatively or additionally, a front differential may be in place to distribute torque to the front axle 57. Transmission 53 is configured to deliver a variable output speed R to output member 14, with transmission output speed R being variably opposable by braking request (Bc), as determined by controller 10.
(020) Controller 10 includes programmable memory 11 and a microprocessor 12 configured to rapidly execute the necessary control logic for implementing and controlling the brake units 13 and! or output member 14 using algorithm 15 (figure 2) which is programmed or stored in memory 11.
Controller 10 is electronically connected to a brake pedal force sensor 16 which is in electric communication with brake pedal 17.
(02 1) Pressure or force sensor 16 is preferably a force or pressure transducer configured or adapted to precisely detect, measure or otherwise determine an applied pressure or force (arrow F in figure 1) imparted to brake pedal 17 by an operator of vehicle 50. The measurements taken by force sensor 16 are transmittable to controller 10 or are otherwise determinable thereby as needed for use with algorithm 15 of the invention, which is described in further detail hereinafter.
(022) Memory 11 of controller 10 is preloaded or preprogrammed with a look-up table 18 of average brake-pedal force values that correspond to the trigger-values (Tr), above which a maximum brake-torque request is communicated to the braking units 13 and/or output member 14, i.e. pedal-force data tables readily accessible by controller 10 in executing algorithm 15.
(023) Algorithm 15 on figure 2 is provided to actively adapt the trigger-force (Tr), required for the maximum brake-torque request, based on the concurrently calculated average brake-pedal force. In an emergency, no two people will apply brake pedal 17 in the same manner and even the same operator will vary their braking pattern over time. Using algorithm 15 inter-personal and intra-personal variation may be properly accounted for.
(024) Using algorithm 15 of the invention, the need for maximum brake-torque should more closely reflect each operator's intention. To ensure the continuous adaptation of the system properties, algorithm 15 is preferably executed per a sufficiently rapid and continuous control loop, preferably of approximately 10 to 20 milliseconds, but which may be performed more or less frequently depending on the available speed of microprocessor 12.
(025) Beginning with step 71, an integer counter (C) is zeroed or initialised in memory 11 of controller 10. Integer counter (C) is any digital or analogue device capable of counting upward by positive whole numbers in response to a predetermined event, and of retaining the current count for access by algorithm 15 as needed and described hereinafter. After counter (C) has been properly zeroed or initialised, algorithm 15 proceeds to step 72.
(026) At step 72, algorithm 15 detects or otherwise determines that a braking event has occurred. A "braking event" hereinafter defines an application of detectable force (F, see figure 1) applied to brake pedal 17 (figure I). Algorithm GG repeats step 72 according to the predetermined control loop, preferably every 10 to 20 milliseconds, until such a braking event is detected. Once a braking event has been properly detected, algorithm 15 proceeds to step 73.
(027) At step 73, algorithm 15 determines whether the brake-pedal applied force (F) detected at step 72, satisfies the predetermined criterion for inclusion in the values microprocessor 12 of controller employs to calculate the average braking input. The criterion for inclusion in the calculation is set to 50 N. If the criterion is satisfied, then algorithm 15 proceeds to step 74. Otherwise, algorithm proceeds to step 79, where the controller 10 communicates to the braking units 13 a braking request proportional to the brake-pedal applied force (F).
(028) At step 74, the algorithm 15 uses the values of the brake-pedal applied force (F) and the previously stored in memory 11 average brake-pedal applied force (Fdf,,I) to calculate an updated value for the average brake-pedal applied force (Favg). After this updated average brake-pedal applied force (Favg) replaces the previous value for average brake-pedal applied force (FdefauIt) in memory 11 of controller 10, algorithm 15 proceeds to step 75.
(029) At step 75, the algorithm 15 retrieves from table 18 (see figure 3) the value of trigger-force (Tr) corresponding to the updated average brake-pedal applied force (Favg). After the trigger-force (Tr) value is temporarily stored in memory 11 of controller 10, algorithm 15 proceeds to step 76 and increments the integer counter by one counter. Then, algorithm 15 proceeds to step 77.
(030) At step 77, algorithm 15 compares integer counter (C) to a predetermined value (n) corresponding to the number of samples used to calculate the average brake-pedal applied force (Favg; see step 74). Upon initial launch of a vehicle 50 (figure 1), i.e. when a vehicle 50 is released to the consumer market from production, integer counter is initialised to a value of zero, i.e. preprogrammed in memory 11 of controller 50 (figure I) to equal zero, so that during the initial braking events only contribute to the calculation of the average brake-pedal applied force (Favg).ValUe (n) is selected to provide sufficient number of braking events to occur before modifving the level of the trigger-force (Tr) for the communication of a maximum brake-torque request.
Preferably, value (n) is set to at least 1 00, however any value (n) may be selected as appropriate within the scope of the invention as needed for a particular vehicle or brake assist system. If counter (C) greater than the predetermined value (n), algorithm 15 proceeds to step 78. If the value of counter (C) is equal to or smaller than the value (n), algorithm 15 proceeds to step 79, where the controller 10 communicates to the braking units 13 and/or the output member 14 a braking request proportional to the brake-pedal applied force (F).
(031) At step 78 algorithm 15 retrieves the stored trigger-force (Tr) value and compares it against the brake-pedal applied force (F). If the brake-pedal applied force (F) is equal to or greater than the trigger-force (Tr), then algorithm 15 proceeds to step 80, where the controller 10 communicates a request for maximum brake-torque to the braking units 13 and/or the output member 14. If the brake-pedal applied force (F) is smaller than the trigger-force (Tr), then algorithm 15 proceeds to step 79. where the controller 10 communicates to the braking units 13 and/or the output member 14 a braking request which is proportional to the brake-pedal applied force (F).
(032) When algorithm 15 arrives to step 80, the controller 10 communicates a request for maximum brake-torque to the braking modules 13 and/or the output member 14.
(033) When algorithm 15 arrives to step 79 instead, the controller 10 communicates to the braking units 13 and/or the output member 14 a braking request which is proportional to the brake-pedal applied force (F).
(034) Turning to figure 3, the adaptation of the trigger-force (Tr) value against the average brake-pedal applied force (Favg) is presented, according to the look-up table 18. X-axis represents the average brake-pedal force (Favg) and Y-axis represents the trigger-force (Tr). The line consists of the corresponding values of average brake-pedal force (Fag) and trigger-force (Tr) according to look-up
table 18.
(035) For example, if after some use of brake pedal 17 the average brake-pedal force (Favg) is lOON, the trigger-force will be approximately 350N. For the controller 10 to communicate a maximum brake-torque request to the braking units 13 and/or the output member 14, the operator must apply a force (F) of 350+ N. If the same or another operator continues to use the brake-pedal and after some time the average brake-pedal force (Favg) increases to 150 N, then the controller 10 will communicate a maximum brake-torque request to the braking units 13 and/or the output member 14, when the operator applies a force (F) of 400+ N on the brake-pedal.
(036) While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practising the invention within the scope of the appended claims.

Claims (9)

  1. SCLAIMSI. A vehicle comprising: a brake pedal for delivering a braking request based on a detectable brake-pedal applied force; a sensor configured to detect the said detectable brake-pedal applied force; at least one electronic or mechanical component configured to slow or stop the vehicle in response to said braking request; a controller configured to determine the brake-pedal applied force required for a maximum braking request, referred to herein for simplicity as trigger-force, and to communicate the said maximum braking torque request, when the said detectable brake-pedal applied force exceeds the trigger-force.
  2. 2. The vehicle of claim I, wherein the said controller is configured to continuously adapt the said trigger-value according to the said previous brake-pedal applied force history.
  3. 3.The vehicle of claim I, wherein the said controller further comprises a memory for storing the said previous brake-pedal applied force history.
  4. 4.The vehicle of claim 3, wherein the said controller is operable for calculating the average brake-pedal applied force history only when the said detectable brake-pedal applied force exceeds a predetermined value.
  5. 5. The vehicle of claim 4, wherein the said memory of said controller comprises a look-up table of average brake-pedal applied force values and corresponding trigger-values for a maximum braking torque request.
  6. 6. A method for adapting the brake-pedal applied force required for a braking system to employ maximum braking torque in a vehicle where the braking system is actuated by a brake pedal having a detectable applied force. The method comprising: detecting the size of the brake-pedal applied force; calculating the average brake-pedal applied force according to previous inputs to the brake pedal; calculating the corresponding value of brake-pedal applied force triggering a maximum braking torque request; communicate a maximum braking torque request to the braking units, if the said detected size of the brake-pedal applied force equals or exceeds the value of the trigger-force.
  7. 7. The method of claim 6, wherein said corresponding value of brake-pedal applied force triggering a maximum braking torque request is determined only after a number of braking events, i.e. detectable brake-pedal force applied on the said brake pedal, have occurred.
  8. 8. An adaptive brake assist system (BAS) for a vehicle having a depressible brake pedal with a detectable brake-pedal applied force, the BAS comprising: a force sensor operatively connected to the depressible brake pedal and operable for determining a braking torque request in response to the detectable brake-pedal applied force; a controller configured to adapt the required brake-pedal applied force for communication of a maximum braking torque request.
  9. 9. The adaptive BAS of claim 8, wherein said adaptive BAS is combined with the vehicle and operable for calculating the average brake-pedal applied force and the corresponding brake-pedal applied force that triggers a maximum braking torque request.
GB0918231.2A 2009-10-17 2009-10-17 Adaptive brake assist system control apparatus and method Expired - Fee Related GB2474506B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB0918231.2A GB2474506B (en) 2009-10-17 2009-10-17 Adaptive brake assist system control apparatus and method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB0918231.2A GB2474506B (en) 2009-10-17 2009-10-17 Adaptive brake assist system control apparatus and method

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GB0918231D0 GB0918231D0 (en) 2009-12-02
GB2474506A true GB2474506A (en) 2011-04-20
GB2474506B GB2474506B (en) 2017-06-28

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5833327A (en) * 1995-10-30 1998-11-10 Aisin Seiki Kabushiki Kaisha Braking force control system for an automotive vehicle
EP1188633A1 (en) * 2000-09-14 2002-03-20 Renault System and method for analysing the braking of a vehicle
DE10118635A1 (en) * 2000-04-18 2002-05-08 Continental Teves Ag & Co Ohg Emergency brake amplification system for road vehicle has sensors monitoring position of brake pedal, its speed of movement and its acceleration from its at rest position and modifies braking accordingly

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5833327A (en) * 1995-10-30 1998-11-10 Aisin Seiki Kabushiki Kaisha Braking force control system for an automotive vehicle
DE10118635A1 (en) * 2000-04-18 2002-05-08 Continental Teves Ag & Co Ohg Emergency brake amplification system for road vehicle has sensors monitoring position of brake pedal, its speed of movement and its acceleration from its at rest position and modifies braking accordingly
EP1188633A1 (en) * 2000-09-14 2002-03-20 Renault System and method for analysing the braking of a vehicle

Also Published As

Publication number Publication date
GB0918231D0 (en) 2009-12-02
GB2474506B (en) 2017-06-28

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PCNP Patent ceased through non-payment of renewal fee

Effective date: 20211017