Equipment and methods for controlling braking systems, braking systems and vehicles

Abstract

This invention relates to an apparatus and method for controlling a braking system of a vehicle, particularly a motor vehicle; a braking system; and a vehicle. The apparatus comprises: a stroke sensor device configured to detect the position of the brake pedal and / or the position of a piston in the master brake cylinder actuated by the brake pedal at multiple times; a pressure sensor device configured to detect the pressure in a fluid within the cylinder at multiple times; and a control device configured to activate a brake assist device when a change in the detected position over time exceeds a predetermined stroke gradient threshold, and, if necessary, additionally when the distance between two detected positions exceeds a predetermined stroke threshold, wherein the stroke gradient threshold or stroke threshold is predetermined based on the detected pressure change.

Description

Technical Field

[0001] The present invention relates to an apparatus and method for controlling the braking system of a vehicle, particularly a motor vehicle, a braking system, and a vehicle. Background Technology

[0002] Many motor vehicles employ so-called brake assist, which is used to increase braking force up to the maximum braking force necessary for total deceleration in the event of emergency or dangerous braking intentionally or initiated by the driver. Here, the basis for this change in the braking force enhancement characteristic curve, or the activation of brake assist, is specifically the detection and evaluation of how the driver operates the brake pedal. Therefore, it can be stipulated that brake assist is activated once a predetermined value for the pedal operation speed and a minimum pressure in the master brake cylinder are exceeded.

[0003] In a so-called brake-by-wire system (where the brake pedal and wheel brakes are decoupled), braking characteristics are based on the interaction between a tandem master brake cylinder and a pedal force simulator hydraulically connected to it. From this interaction is derived a pedal force-pedal travel-characteristic curve, which the driver can feel when operating the brake pedal. During emergency braking, a corresponding reaction force acts on the pedal operation and allows for a defined pedal operating speed. This is determined based on the pedal travel detected by a travel sensor and compared to a pre-given trigger threshold. If the trigger threshold is exceeded, brake assist is triggered, or activated.

[0004] Residual air in the simulator circuit—specifically in the tandem master brake cylinder, the pedal force simulator, and / or the hydraulic connection between the tandem master brake cylinder and the pedal force simulator (which may always reappear due to varying degrees of bleeding)—can cause a shift in the pedal force-pedal travel characteristic curve, resulting in a smaller reaction force on the brake pedal at the start of braking when residual air is present. Consequently, the brake pedal bends or continues to deform more strongly during operation, leading to higher pedal operating speeds, especially during faster braking maneuvers, compared to when there is no residual air. This can potentially result in earlier, undesirable activation of brake assist. Summary of the Invention

[0005] The objective of this invention is to provide an apparatus and method for controlling a vehicle's braking system, a braking system, and a vehicle capable of reliably activating braking assistance.

[0006] This task is accomplished by an apparatus and method for controlling a vehicle braking system according to the invention, as well as a braking system having such an apparatus and a vehicle having such a braking system.

[0007] According to a first aspect of the invention, an apparatus for controlling a braking system is provided, the apparatus comprising: a master brake cylinder assembly, particularly a tandem master brake cylinder, the master brake cylinder assembly having at least one cylinder and at least one piston, the piston being movably supported in the cylinder and configured to pressurize fluid in the cylinder when operated by a brake pedal; one or more braking devices configured to apply braking force to one or more wheels of a vehicle; and a brake assist device, the brake assist device being detachable from an active state and deactivated, and the brake assist device being configured to increase the braking force relative to the deactivated state in the active state, the braking force being applied to the wheels of the vehicle by the braking devices. Here, the device includes: a stroke sensor device configured to detect the position of the brake pedal and / or the position of the piston operated by the brake pedal at multiple times; a pressure sensor device configured to detect the pressure in the fluid in the cylinder at multiple times; and a control device configured to activate the brake assist device when the change of the detected position over time exceeds a predetermined stroke gradient threshold and optionally when the distance between two detected positions exceeds a predetermined stroke threshold, wherein the predetermined stroke gradient threshold or stroke threshold is determined based on the detected pressure change.

[0008] According to a second aspect of the invention, a braking system for a vehicle, particularly a motor vehicle, comprises: a master brake cylinder assembly, particularly a tandem master brake cylinder, the master brake cylinder assembly having at least one cylinder and at least one piston movably supported in the cylinder and configured to pressurize fluid in the cylinder when operated by a brake pedal; one or more braking devices configured to apply braking force to one or more wheels of the vehicle; and a brake assist device, the brake assist device being detachable from an active state and deactivated, and the brake assist device being configured to increase the braking force relative to the deactivated state in the active state, the braking force being applied to the wheels of the vehicle by the braking devices; and an apparatus according to the first aspect.

[0009] According to a third aspect of the invention, a vehicle, particularly a motor vehicle, has a plurality of wheels and a braking system according to a second aspect.

[0010] According to a fourth aspect of the invention, a method is provided for controlling a braking system of a vehicle, particularly a motor vehicle, wherein the braking system comprises: a master brake cylinder assembly, particularly a tandem master brake cylinder, the master brake cylinder assembly having at least one cylinder and at least one piston, the piston being movably supported in the cylinder and configured to pressurize fluid in the cylinder when actuated by a brake pedal; one or more braking devices configured to apply braking force to one or more wheels of the vehicle; and a brake assist device, the brake assist device being detachable from an active state and deactivated, and the brake assist device being configured to increase the braking force relative to the deactivated state in the active state, the braking force being applied to the wheels of the vehicle by the braking devices. The method comprises the steps of: detecting the position of the brake pedal and / or the position of the piston actuated by the brake pedal at multiple times; detecting the pressure in the fluid in the cylinder at multiple times; and activating the brake assist device when a change in the detected position over time exceeds a predetermined stroke gradient threshold and optionally when the distance between two detected positions exceeds a predetermined stroke threshold, wherein the stroke gradient threshold or stroke threshold is predetermined based on the detected pressure change.

[0011] Unless otherwise stated, in the context of this disclosure, the terms “position” and “travel” relating to the brake pedal are used synonymously. Accordingly, the terms “position change” and “travel gradient” are also used synonymously.

[0012] The present invention is preferably based on the following means: the brake assist device is activated only when the travel of the brake pedal or the piston coupled to the brake pedal exceeds a travel gradient threshold when the brake pedal is actuated, the travel gradient threshold being determined or pre-defined based on the detected time characteristics of the pressure in the fluid. Optionally, it can be specified that the brake assist device is activated only when the travel of the brake pedal or the piston coupled to the brake pedal, when the brake pedal is actuated, exceeds the travel threshold in addition to the travel gradient threshold, the travel threshold also being determined or pre-defined based on the detected time characteristics of the pressure in the fluid. The travel gradient threshold here is the minimum speed at which the brake pedal or piston must be actuated in order to activate brake assist. Correspondingly, an optional travel threshold is the minimum travel that the brake pedal or piston must travel in order to activate brake assist. The minimum speed or minimum travel required for the brake pedal or piston to activate brake assist depends here on the detected time characteristics of the pressure. That is, the detected pressure or the time characteristics of the pressure are used to determine the travel gradient threshold or travel threshold, and the detected positional change of the brake pedal or piston is checked based on the travel gradient threshold or travel threshold. Therefore, the detected pressure itself or the time characteristics of the pressure are not the (primary) criterion for triggering brake assist. However, it can be specified that the activation of brake assist depends on the detection of a pre-defined travel gradient threshold or travel threshold being exceeded when the brake pedal or piston is operated, and additionally, the detected pressure itself or the time characteristics of the pressure satisfy a defined pre-defined criterion, such as exceeding a pre-defined pressure threshold and / or a pre-defined pressure gradient threshold.

[0013] The present invention can, in particular, reduce or even eliminate the influence of residual air in the simulator circuit of a braking system, such as a brake-by-wire system also known as a pedal-decoupled braking system. Thus, the presence of residual air generally results in a significantly higher travel gradient (pedal speed) when the brake pedal is operated, compared to the absence of residual air, because the pressure and therefore the reaction force only rise when the air is sufficiently compressed, which can lead to undesirable activation of brake assist. By selecting or pre-setting travel gradient thresholds and / or travel thresholds according to the invention in relation to the dynamics of the detected pressure, this situation can be prevented or at least reduced. Consequently, dangerous or emergency braking intended by the vehicle driver when necessary can be identified significantly more reliably and supported accordingly by the activation of brake assist.

[0014] Therefore, overall, the present invention achieves reliable activation of braking assistance.

[0015] The brake assist device is preferably a brake force enhancement device or a component or at least a function of a brake force enhancement device, which can increase the braking force up to the maximum braking force required for total deceleration in the event of emergency braking or dangerous braking intentionally or initiated by the driver. Preferably, in vehicles equipped with brake force enhancement devices, the braking force is enhanced to a certain extent even during normal operation, i.e., when the brake assist device is not activated in the event of emergency braking or dangerous braking.

[0016] Preferably, the change in detected pressure is given by the time offset between the start of the change in detected position and the start of the change in detected pressure, particularly the start of an increase, with a pre-defined stroke gradient threshold or stroke threshold depending on the change in detected pressure. The time offset thus characterizes the time delay between the start of brake pedal actuation and the start of pressure change, particularly the start of a pressure increase, in the master brake cylinder. From this time delay, it can be inferred whether or to what extent a deviation exists in the braking system, such as that caused by residual air in the simulator circuit, and the stroke gradient threshold and / or stroke threshold are adapted accordingly based on this deviation. Preferably, here, the stroke gradient threshold and / or stroke threshold increase with the time offset, particularly when the time offset exceeds a pre-defined time offset. The stroke gradient threshold or stroke threshold preferably increases proportionally to the time offset, but may also increase and / or decrease with the time offset in other ways.

[0017] Alternatively or additionally, the change in detected pressure is given by the spatial offset between the detected position when the detected position begins to change and the detected pressure when it begins to change, particularly when it begins to rise, with a pre-defined stroke gradient threshold or stroke threshold depending on the change in detected pressure. Similar to the time offset described above, the spatial offset characterizes the travel of the brake pedal between the start of brake pedal actuation and the start of pressure change in the master brake cylinder, particularly the start of pressure rise. From this travel, it can be inferred whether or to what extent a deviation exists in the braking system, such as that caused by residual air in the simulator circuit, and the stroke gradient threshold and / or stroke threshold are adapted accordingly. Preferably, here, the stroke gradient threshold and / or stroke threshold increase with the spatial offset, particularly when the spatial offset exceeds a pre-defined spatial offset. The stroke gradient threshold or stroke threshold preferably increases proportionally to the spatial offset, but may also increase and / or decrease with the spatial offset in other ways.

[0018] Alternatively or additionally, the detected pressure change is given by the gradient of the detected pressure, with a pre-defined stroke gradient threshold or stroke threshold depending on the detected pressure change. The detected pressure gradient (also referred to as pressure gradient, pressure change rate, or pressure change velocity) thus characterizes the extent of pressure rise in the fluid of the master brake cylinder in response to actuation of the brake pedal. From this pressure rise, it can be inferred whether or to what extent a deviation exists in the braking system, such deviation as caused by residual air in the simulator circuit, and the stroke gradient threshold and / or stroke threshold are adapted accordingly to the deviation. Preferably, here, the stroke gradient threshold and / or stroke threshold increase as the detected pressure gradient decreases or decreases as the detected pressure gradient increases, particularly when the detected pressure gradient is below a pre-defined value. The stroke gradient threshold or stroke threshold may have a trend that preferably extends proportionally to the detected pressure gradient in one or more segments, but may also increase and / or decrease in other ways with the detected pressure gradient. Attached Figure Description

[0019] Other preferred or alternative aspects, embodiments, and advantages of the invention are described below with reference to the accompanying drawings. In the drawings:

[0020] Figure 1 An example of a braking system is shown;

[0021] Figure 2 Examples of time curves showing the travel of the brake pedal and the pressure in the master brake cylinder are shown for braking systems with no residual air (solid line) and with residual air (dashed line), respectively.

[0022] Figure 3 An example illustrating the correlation between the travel gradient threshold and the time offset between the start of change at the detected location and the start of increase in the detected pressure;

[0023] Figure 4 An example illustrating the correlation between the travel threshold and the time offset between the start of change at the detected location and the start of rise in the detected pressure;

[0024] Figure 5 An example illustrating the correlation between the stroke gradient threshold and the spatial offset between the detected position when the detected position begins to change and the detected position when the detected pressure begins to rise; and

[0025] Figure 6 An example illustrating the correlation between the travel gradient threshold and the pressure gradient is shown. Detailed Implementation

[0026] Figure 1An example of a braking system 1 with a master brake cylinder assembly is shown, which is configured herein as a tandem master brake cylinder 2, also abbreviated below as "THz" and has first and second cylinder sections 3 or 4 and first and second pistons 5 or 6, which are movably supported in the respective cylinder sections 3 or 4 and are configured to pressurize the fluid in the THz2 when operated by a brake pedal 7, which is shown only schematically herein (see the left-pointing arrows respectively).

[0027] The example shown involves a so-called pedal-decoupled braking system 1, also known as a brake-by-wire system, in which the brake pedal 7 and wheel brakes 8 are decoupled from each other. Here, the braking characteristics felt by the driver when operating the brake pedal 7 are based on the coordinated action between the THz 2 and the pedal force simulator 9 hydraulically connected thereto, which has a piston 10 that presses against an elastic element 11 according to the pressure in the THz 2 (see the right-pointing arrow at the piston 10).

[0028] In addition, a brake assist device is provided, which can be switched between an active state and an inactive state. In the active state, the braking force (applied to the vehicle's wheels by wheel brakes 8) is increased compared to the inactive state. The brake assist device may be configured as part or part of the function of a brake force enhancement device, which, even when the brake assist device is inactive, causes a certain degree of increase in the braking force on the wheels.

[0029] To correspondingly enhance braking force, a linear actuator 12 is provided in this example, which applies additional pressure to the brake fluid 17 via the movement of piston 13 (see the left-pointing arrow at piston 13). This additional pressure is transmitted to the wheel brakes 8 via plunger energizing valve 18 and intake valve 19. Furthermore, each wheel brake 8 is equipped with an exhaust valve 20. The fluid in the first or second cylinder section 3 or 4 of THz2 is hydraulically decoupled or coupled to the wheel brakes 8 via driver release valve 21.

[0030] In addition, a control device 16 is provided, which can activate or deactivate the braking assist device in the event of emergency braking or dangerous braking to enhance braking force by correspondingly controlling the relevant components, in particular the linear actuator 12 and / or the plunger energizing valve 18 and / or the driver disconnect valve 21.

[0031] In addition, a stroke sensor 14 is provided, which detects the current position of the brake pedal 7 and / or the stroke traveled by the first piston 5 moving through the brake pedal 7 at multiple times, particularly continuously.

[0032] The pressure sensor 15 detects the pressure in THz2 at multiple times, particularly continuously, especially the pressure in the fluid in the second cylinder section 4.

[0033] Control device 16 is configured to detect when the position of brake pedal 7 or piston 5 or the time change ds / dt of the travel since the start of actuation exceeds a pre-defined travel gradient threshold ds. x / dt x Furthermore, if necessary, when the distance s between the two detected positions of the brake pedal 7 or piston 5, particularly the travel s traversed since the start of operation, exceeds a predetermined travel threshold s. x At this time, the braking assist device is put into the active state. The pre-defined stroke gradient threshold ds is considered in this test. x / dt x or travel threshold s x This depends on the changes in pressure detected, which are referred to below. Figures 2 to 6 To elaborate further.

[0034] Figure 2 Examples are shown, respectively, of the time curves of the travel s of the brake pedal 7 and the pressure p in the THz2, detected by the travel sensor 14 or the pressure sensor 15, for braking system 1 with no residual air (solid line) and with residual air (dashed line) in the simulator circuit (i.e., in THz2 and / or pedal force simulator 10 and / or in the hydraulic connection between THz and pedal force simulator). The travel or pressure curves shown in the examples typically appear during rapid actuation of the brake pedal 7, such as in cases of dangerous or emergency braking intended by the driver.

[0035] If there is little or no residual air in the simulator circuit, actuation of the brake pedal 7 causes a relatively steep rise in pressure p (solid line) in THz2 after a certain time delay t0, resulting in a relatively large pressure gradient dp0 / dt0. This pressure gradient resists pedal movement, preventing the travel s (solid line) of the brake pedal 7 from rising too quickly. Conversely, if residual air is present in the simulator circuit, actuation of the brake pedal 7 results in a relatively steep rise in travel s (dashed line) because the pressure p (dashed line) in THz2 rises after a larger time delay t1 and also exhibits a less steep rise, i.e., a smaller pressure gradient dp1 / dt1. This causes the reaction force acting on the pedal movement to appear later and rise more slowly.

[0036] To eliminate or at least reduce the potential influence of residual air in the simulator circuit on the activation of brake assist, a travel gradient threshold and / or travel threshold are determined and / or pre-given or influenced based on the state of the detected pressure p, which are to be reached or exceeded by the detected brake pedal travel 7 in order to trigger the activation of brake assist.

[0037] Preferably, the travel gradient threshold and / or travel threshold are pre-defined based on the time offset between the start of change of the detected position s of the brake pedal 7 and the start of increase of the detected pressure p. Alternatively or additionally, the travel gradient threshold and / or travel threshold may also be pre-defined based on the spatial offset between the detected position when the detected position of the brake pedal 7 begins to change and the detected position when the detected pressure p begins to increase. Alternatively or additionally, the travel gradient threshold and / or travel threshold may also be pre-defined based on the pressure gradient. This is referred to below. Figures 3 to 6 To elaborate further.

[0038] Figure 3 This shows the pre-given travel gradient threshold ds x / dt x The time offset t between the point at which the detected position s begins to change and the point at which the detected pressure p begins to rise. x An example of correlation. In the exemplary curve shown, when the time offset t... x When t1 is less than t1, the travel gradient threshold ds x / dt x Equals ds0 / dt0 (see Figure 2 If the time offset t x If the value is greater than t1, then the travel gradient threshold ds x / dt x With time offset t x It increases linearly (solid line). However, alternatively, the travel gradient threshold ds... x / dt x The increase of can also have other trends (dashed lines). Generally, the run-length gradient threshold ds x / dt x The temporal correlation can also be more complex, as illustrated further below by example.

[0039] The time offset can preferably be continuously determined based on the braking speed during each braking maneuver and generate a mass value Q. Luft The mass value describes the exhaust state of the simulator's braking circuit. For example, Q Luft =1 corresponds to the normal state where there is no remaining air, Q Luft=10 implies a large amount of residual air. For each braking speed, a pressure rise is expected after a defined time: a larger time delay for slow braking, and a correspondingly smaller time delay for faster braking. Therefore, the mass value Q is preferably derived from the time delay under different braking speed conditions. Luft .

[0040] Figure 4 Show the pre-defined travel threshold s x The time offset t between the point at which the detected position s begins to change and the point at which the detected pressure p begins to rise. x Examples of correlation. With in Figure 3 Similarly, in the example shown, in the illustrative curve, when the time offset t... x When t1 is less than t1, the travel threshold s x Equal to s0 (see Figure 2 If the time offset t x If the value is greater than t1, then the travel threshold s x With time offset t x It increases linearly (solid line). Alternatively, the travel threshold s... x The increase in can also have other trends (dashed lines). Generally, the travel threshold s x The time correlation can also be more complex, as illustrated further below by example. The time offset can preferably be determined continuously based on the actuation speed at each braking maneuver, generating a mass value Q. Luft The mass value describes the exhaust state of the simulator's braking circuit. For example, Q Luft =1 corresponds to the normal state where there is no remaining air, Q Luft =10 implies a large amount of residual air. For each braking speed, a pressure rise is expected after a defined time: a larger time delay for slow braking, and a correspondingly smaller time delay for faster braking. Therefore, the mass value Q is preferably derived from the time delay under different braking speed conditions. Luft .

[0041] Figure 5 This shows the pre-given travel gradient threshold ds x / dt x The spatial offset sp between the position s detected at the beginning of the change in the detected position s of the brake pedal 7 and the position s detected when the detected pressure p begins to rise. x Examples of correlation. In the exemplary curve trajectory shown, when the spatial offset sp x When sp0 is less than ds, the travel gradient threshold ds x / dt xEquals ds0 / dt0 (see Figure 2 If the spatial offset is sp x If the value is greater than sp0, then the travel gradient threshold ds x / dt x With spatial offset sp x It increases linearly (solid line). However, alternatively, the travel gradient threshold ds... x / dt x The increase can also have other directions (dashed lines).

[0042] Spatial offset can preferably be determined continuously during each braking operation.

[0043] Figure 6 This shows the pre-given travel gradient threshold ds x / dt x The gradient dp of the detected pressure p x / dt x An example of the correlation. In the exemplary curve trajectory shown, when the pressure gradient dp x / dt x When the value is greater than dp1 / dt1, the travel gradient threshold ds x / dt x Equals ds0 / dt0 (see Figure 2 If the pressure gradient dp x / dt x If the value is less than dp1 / dt1, then the travel gradient threshold ds x / dt x (Solid line) As the pressure gradient dp x / dt x The decrease increases or increases with the pressure gradient dp x / dt x It decreases as it increases.

[0044] In principle, the threshold mentioned in connection with this disclosure, namely the run-length gradient threshold ds x / dt x Or travel threshold ds x And / or the change in the travel gradient threshold or travel threshold can be given or pre-given absolutely or relatively, or as a factor. Thus, a factor of, for example, 100% or 1, could mean that there is no effect caused by the remaining air and accordingly no matching or increase of the relevant threshold, while a factor of 110% or 1.1 would mean that the relevant threshold is increased by 10%.

[0045] A similar measure can be selected when, for example, the driver presses the brake pedal and depresses it rapidly. Here, it is preferable to influence the threshold already matched for this situation in a similar manner. However, the remaining air in the simulator circuit does not have as much effect here, because the driver has already compressed most of any potential air bubbles based on the intensity of the maneuver.

[0046] List of reference numerals

[0047] 1 Braking System

[0048] 2 master brake cylinders, tandem master brake cylinders (THz)

[0049] 3. First cylinder section

[0050] 4. Second cylinder section

[0051] 5 First Piston

[0052] 6 Second Piston

[0053] 7. Brake pedal

[0054] 8. Braking system, wheel brakes

[0055] 9-Pedal Force Simulator

[0056] 10 Pistons

[0057] 11 elastic elements

[0058] 12 linear actuators

[0059] 13 Pistons (on linear actuators)

[0060] 14 stroke sensors

[0061] 15 pressure sensors

[0062] 16 control devices

[0063] 17 Braking Fluid

[0064] 18-piston connecting valve

[0065] 19 Intake Valve

[0066] 20 exhaust valve

[0067] 21 Driver Separation Valve

[0068] s location, itinerary

[0069] p pressure

[0070] t time

[0071] Q quality value

Claims

1. A device for controlling a vehicle's braking system (1), wherein, The braking system (1) comprises: a master brake cylinder assembly (2) having at least one cylinder (3, 4) and at least one piston (5, 6), the piston being movably supported in the cylinder (3, 4) and configured to pressurize fluid in the cylinder (3, 4) when operated by a brake pedal (7); one or more brake devices (8) configured to apply braking force to one or more wheels of the vehicle; and brake assist devices (12, 13, 17, 18, 21) capable of being in an active state and an inactive state, and configured to increase the braking force relative to the inactive state in the active state, the braking force being applied to the wheels of the vehicle by the brake devices (8), and the device having: -Stroke sensor device (14), the stroke sensor device is configured to detect the position of the brake pedal (7) and / or the position of the piston (5) operated by the brake pedal (7) at multiple times (t); - Pressure sensor device (15), the pressure sensor device being configured to detect the pressure (p) in the fluid in the cylinder (4) at multiple times (t); and - Control device (16), the control device is configured to, when the change of the detected position over time (ds / dt) exceeds a pre-given travel gradient threshold (ds x / dt x ) and optionally when the distance (s) between two detected locations exceeds a pre-defined travel threshold (s). x When the brake assist device (12, 13, 17, 18, 21) is activated, a stroke gradient threshold (ds) is pre-defined based on the detected change in pressure (p). x / dt x ) or travel threshold (s x ).

2. The device according to claim 1, wherein, The change in detected pressure (p) is measured by the time shift (t0, t1, t2) between the start of the change at the detected location and the start of the change in detected pressure (p). x (This is given in the original text.) 3. The device according to claim 2, wherein, The change in the detected pressure (p) is measured by the time shift (t0, t1, t2) between the start of the change at the detected location and the start of the rise in the detected pressure (p). x (This is given in the original text.) 4. The device according to claim 2, wherein, The stroke gradient threshold (ds) x / dt x ) and / or travel threshold (s x With the time offset (t) x (and thus increase) 5. The device according to any one of claims 2 to 4, wherein, When the time offset (t) x When the time offset exceeds a pre-given time offset (t1), the run-length gradient threshold (ds) is reached. x / dt x ) and / or travel threshold (s x With the time offset (t) x (and thus increase) 6. The device according to any one of claims 1 to 4, wherein, The change in detected pressure (p) is measured by the spatial offset (sp) between the detected position when the change begins and the detected position when the pressure (p) begins to change. x (This is given in the original text.) 7. The device according to claim 6, wherein, The change in detected pressure (p) is measured by the spatial offset (sp) between the detected position when the change begins and the detected position when the detected pressure (p) begins to rise. x (This is given in the original text.) 8. The device according to claim 6, wherein, The stroke gradient threshold (ds) x / dt x ) and / or travel threshold (s x With the spatial offset (sp) x (and thus increase) 9. The device according to claim 6, wherein, When the spatial offset (sp) x When the spatial offset exceeds a pre-defined spatial offset (sp0), the travel gradient threshold (ds) is reached. x / dt x ) and / or travel threshold (s x With the spatial offset (sp) x (and thus increase) 10. The device according to any one of claims 1 to 4, wherein, The change in the detected pressure (p) is given by the gradient (dp / dt) of the detected pressure (p).

11. The device according to claim 10, wherein, The stroke gradient threshold (ds) x / dt x ) and / or travel threshold (s x It increases as the gradient (dp / dt) of the detected pressure (p) decreases.

12. The device according to claim 10, wherein, When the gradient of the detected pressure (dp / dt) is lower than a predetermined value (dp1 / dt1), the travel gradient threshold (ds) is reached. x / dt x ) and / or travel threshold (s x It increases as the gradient (dp / dt) of the detected pressure (p) decreases.

13. The device according to any one of claims 1 to 4, wherein, The vehicle in question is a motor vehicle.

14. The device according to any one of claims 1 to 4, wherein, The main brake cylinder device is a tandem main brake cylinder.

15. A braking system (1) for a vehicle, said braking system having: - Master brake cylinder assembly (2), the master brake cylinder assembly having at least one cylinder (3, 4) and at least one piston (5, 6), the piston being movably supported in the cylinder (3, 4) and configured to pressurize the fluid in the cylinder (3, 4) when operated by the brake pedal (7); - One or more braking devices (8), said braking devices being configured to apply braking force to one or more wheels of the vehicle; - Brake assist devices (12, 13, 17, 18, 21), said brake assist devices can be placed in an active state and an inactive state, and said brake assist devices are configured to, in the active state, increase the braking force relative to the inactive state, said braking force being applied to the wheels of the vehicle by the braking device (8), and - The device according to any one of claims 1 to 14.

16. A vehicle having a plurality of wheels and a braking system (1) according to claim 15.

17. A method for controlling a braking system (1) of a vehicle, wherein, The braking system (1) comprises: a master brake cylinder assembly (2) having at least one cylinder (3, 4) and at least one piston (5, 6), the piston being movably supported in the cylinder (3, 4) and configured to pressurize fluid in the cylinder (3, 4) when operated by a brake pedal (7); one or more brake devices (8) configured to apply braking force to one or more wheels of the vehicle; and brake assist devices (12, 13, 17, 18, 21) capable of being in an active state and an inactive state, and configured to increase the braking force relative to the inactive state in the active state, wherein the braking force is applied to the wheels of the vehicle by the brake devices (8), and the method comprises the following steps: -Detect the position of the brake pedal (7) and / or the position of the piston (5) operated by the brake pedal at multiple times (t). - The pressure (p) in the fluid in cylinder (4) is detected at multiple times (t), and -When the change in the detected position over time (ds / dt) exceeds a pre-defined travel gradient threshold (ds x / dt x ) and optionally when the distance (s) between two detected locations exceeds a pre-defined travel threshold (s). x When the pressure (p) is detected, the brake assist devices (12, 13, 17, 18, 21) are activated, wherein a stroke gradient threshold (ds) is pre-defined based on the detected pressure (p). x / dt x ) or travel threshold (s x ).

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