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
  • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
  • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
  • B60T13/66—Electrical control in fluid-pressure brake systems
  • B60T13/662—Electrical control in fluid-pressure brake systems characterised by specified functions of the control system components
• • 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
  • B60T13/00—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems
  • B60T13/10—Transmitting braking action from initiating means to ultimate brake actuator with power assistance or drive; Brake systems incorporating such transmitting means, e.g. air-pressure brake systems with fluid assistance, drive, or release
  • B60T13/66—Electrical control in fluid-pressure brake systems
  • B60T13/68—Electrical control in fluid-pressure brake systems by electrically-controlled valves
  • B60T13/686—Electrical control in fluid-pressure brake systems by electrically-controlled valves in hydraulic systems or parts thereof
• • 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

Definitions

• the invention relates to a device and a method for controlling a brake system, in particular for motor vehicles, for realizing a brake assistance function.
• active brake boosters which are used to shorten the braking distance.
• the brake booster is controlled externally by a so-called brake assistant.
• the function of the brake assistant which improves the braking ability of a car in the hands of a less experienced driver and thus shortens the braking distance, is as follows.
• a displacement sensor measures the speed at which a brake pedal is depressed. If the driver hesitates after the spontaneous step on the pedal and does not dare to depress the pedal until the control of an anti-lock braking system (ABS) responds, the brake assistant intervenes.
• ABS anti-lock braking system
• an electronic control unit calculates whether there is emergency braking and, via a solenoid valve, gives the booster, which works in the ON / OFF process, the command to deliver the full boosting force.
• a release switch is integrated in the booster so that the brake assistant, once triggered, does not unintentionally brake the vehicle to a standstill. This switches off the brake assistant as soon as the driver releases the brake pedal.
• the object of the invention is to provide a device and a method for controlling a brake system, in particular for motor vehicles, for realizing a brake assistance function, which implement a safe and comfortable shortening of the braking distance and avoid false tripping.
• a brake pedal can be used, which is decoupled from the brake system in such a way that the driver input into the system, for example the actuation path of the brake pedal, is variable and dependent on further inputs, for example the speed at which the pedal is depressed, by a control unit in which the Brake system to be implemented braking deceleration can be converted.
• a damping and / or a counterforce of the brake pedal can be set accordingly via a control unit, the control unit being able to correspondingly reduce the damping and / or the counterforce of the brake pedal when the brake assistance function is activated, and the resultant brake pedal function is then determined via a displacement sensor of the brake pedal
• the actuation path of the brake pedal can then be used to determine the braking deceleration to be implemented by the braking system.
• Brake assistance function the driver controls the brake system 100 percent. This is in contrast to the prior art described above, since the brake assistant there actuates the brake system in some cases independently of the actual position of the brake pedal by means of appropriate control logic. This is excluded in the invention, since the braking deceleration of the brake system is set as a function of the determined actuation path (actual position) of the brake pedal. Because the damping and / or the counterforce of the brake pedal is reduced, it can be expected that the driver continues to depress the brake pedal than when the braking assistance function is not activated, so that the braking deceleration implemented by the braking system increases. As a result, the braking distance is reduced.
• a control unit can change a system gain depending on an actuation path determined by the displacement sensor, an actuation speed and / or an actuation acceleration of the brake pedal when the brake assistance function is activated.
• the system gain can correspond to a ratio of the determined actuation path to a braking deceleration to be implemented by the braking system.
• the counterforce and / or the damping of the brake pedal does not change, but the driver input is amplified to a greater extent via the brake pedal, so that a shortened braking distance can also be achieved when the brake assistance function is activated.
• Fig. 1 is a schematic block diagram of the invention
• 2 is a graphical representation of the actuation path of the brake pedal over the actuation force
• 3 shows a flowchart for changing the damping and / or the counterforce of the brake pedal
• Fig. 4 is a graphical representation of the counterforce
• Fig. 5 is a flow chart regarding an increase in system gain.
• the displacement sensor 2 can detect the actuation angle of the brake pedal 1 or the actuation path of the brake pedal 1.
• the displacement sensor 2 is connected to a brake system 4 and in particular to a control unit 5 via a corresponding signal line 3.
• the control unit 5 first determines whether a braking assistance function is required or not. If this is the case, the control unit 5 determines, for example, a correspondingly reduced counterforce of the pedal components of the brake pedal 1, which are not shown. These pedal components can have a static (spring) and a speed-dependent component (damping). The counterforce can be reduced, for example, by minimizing the damping. This can be done, for example, by changing the hydraulic cross section.
• the control unit 5 can also leave the damping and / or the counterforce of the brake pedal 1 unchanged and increase the system gain accordingly if the Brake assistance function has been activated.
• influencing the counterforce and / or the damping of the brake pedal 1 and the system reinforcement can also be combined.
• the control unit 5 of the brake system 4 determines a braking deceleration to be implemented by the brake system 4. This takes place with the aid of, for example, the determined actuation path, the determined actuation speed and / or the determined actuation acceleration, although other factors can of course also be included (for example the vehicle speed, a yaw rate, a steering angle, etc.).
• wheel brakes 6 are now actuated via corresponding control lines 7 in order to bring about the desired deceleration (for the sake of simplicity, only one wheel brake 6 is shown).
• the control lines 7 can be electrical and / or hydraulic control lines for controlling the wheel brakes 6.
• FIGS. 4 and 5 show a graphical representation of the actuation path over the actuation force (or the input force F e ) of the brake pedal 2.
• the actuation force F el results in an actuation path of the brake pedal 1 of xl.
• an actuation path x2 results for the same actuation force F el of the brake pedal 1.
• a reduction in the damping and / or the counterforce of the brake pedal results in a stronger or deeper depression of the brake pedal 1 by the driver, so that the braking distance can be effectively reduced without the complete control of the Braking events or the braking process by the driver.
• FIGS. 4 and 5 as will be explained in the following).
• the flow chart according to FIG. 3 is intended to schematically represent a possible sequence that is carried out, for example, by the control unit 5. This sequence is started in a step 100, in which case a query is made in a step 101 as to whether the brake assist or the brake assist function is activated. If this is not the case, the system branches back between steps 100 and 101.
• the activation of the brake assistance function can be initiated by the control unit 5, for example, when the depression speed of the brake pedal 1 is greater than a threshold value (however, this is only intended to represent an example of a possible activation input of the brake assistance function).
• the program then branches to a step 102 in which the damping and / or the counterforce of the brake pedal 1 is reduced. This can be done, for example, by varying the hydraulic effective cross sections of the brake pedal 1 accordingly.
• the actuation path x of the brake pedal 1 is then detected in a step 103 and a brake deceleration corresponding to the actuation path is determined in a step 104.
• this determined braking deceleration is output to the braking system and the wheel brakes 6 are then actuated in such a way that this braking deceleration is achieved.
• the aforementioned process ends in a step 106.
• the static counterforce of the brake pedal 1 (spring and / or damping effect) can thus be limited to a value that corresponds, for example, to 30 percent braking; since the normal range of action of the driver comprises 0-30% deceleration, ie the driver knows this deceleration area or area of the pedal counterforce. This causes an accelerating excess force of the foot force on the brake pedal 1 and thus a faster foot movement and a stronger or deeper depression of the brake pedal 1. The resulting pedal travel is thus a measure of the deceleration to be implemented.
• the value to be set for the counterforce can depend, for example, on the speed at which the foot accelerates (detected by the speed at which the brake pedal 1 accelerates).
• a static counterforce dependent on the pedal travel can be reduced to a value that corresponds, for example, to 30 percent braking (lower force-travel characteristic curve). This then also causes an accelerating excess force of the foot force on the brake pedal 1 and thus a faster foot movement.
• the dynamic counterforce can be reduced to a possibly speed-dependent value of the initial speed, whereby when reducing the damping, care must be taken to ensure that the tendency of the brake pedal to oscillate (self-movement of the brake pedal 1) is reliably prevented. The static pedal characteristic would be maintained and only the damping force that would prevent movement would be reduced.
• the 4 shows an increase in the system gain.
• the broken lines show on the one hand the input force F e (corresponds to the counterforce) and the output force F a .
• the output force F a is a value that corresponds to the braking deceleration. If the brake assist or brake assist function is now switched on, the system gain is increased.
• the solid thick line shows a maximum gain. After the brake assistant is switched off, the system gain approaches the normal gain again, so that the next time the brake system is actuated, the normal gain is present again. Approaching the normal gain takes place continuously or gradually, so that the system gain is shut down as conveniently as possible.
• any gradations are possible between the dashed line of F a and the continuous thick line of F a .
• intermediate values can be selected for the system gain, so that the increased profile of the output force F a lies between the thick solid line and the dashed line.
• the determination of the system gain and thus also the reinforcement line at a certain point in time during the activation of the brake assistance function and after the activation of the brake assistance function can also be dependent on other factors (for example the vehicle speed, the Vehicle weight, etc.).
• step 5 shows an example of a possible sequence that can be carried out in the control unit 5, for example.
• a branch is made to a step 201 by querying whether the brake assistance function is activated or not. If this is not the case, the system branches back between steps 200 and 201. If the brake assist function is activated, the system gain is increased in a step 202. The actuation path of the brake pedal 1 is then detected in a step 203. A braking deceleration is then determined in a step 204, which corresponds to the detected actuation path, the increased system gain in step 202 being taken into account. The braking deceleration is then output to the brake system 4 in a step 205 and the sequence ends in a step 206.
• the arithmetic system gain (actuation travel or pedal travel to decelerate) is greatly increased, the counterforce of the brake pedal 1 remaining unaffected.
• the resulting system gain can be dependent on the pedal movement (actuation path, actuation speed and / or actuation acceleration) and is determined during the application of the brake (positive pedal speed).
• the brake is released, the system gain is continuously reduced down to the normal gain.
• modules and functions described in the invention can also be implemented individually and / or in any combination.

Landscapes

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

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Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (3)

Families Citing this family (15)

Citations (8)

Family Cites Families (9)

• 1998
  • 1998-06-05 DE DE1998125231 patent/DE19825231A1/de not_active Withdrawn
• 1999
  • 1999-05-31 JP JP2000553314A patent/JP4743961B2/ja not_active Expired - Fee Related
  • 1999-05-31 WO PCT/EP1999/003761 patent/WO1999064281A1/de active Application Filing

Patent Citations (8)

Non-Patent Citations (1)

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