EP3990333A1

EP3990333A1 - Method and device for the dynamic optimization of a braking distance of vehicles, in particular of rail vehicles

Info

Publication number: EP3990333A1
Application number: EP20733259.4A
Authority: EP
Inventors: Ralf FURTWÄNGLER
Original assignee: Knorr Bremse Systeme fuer Schienenfahrzeuge GmbH
Current assignee: Knorr Bremse Systeme fuer Schienenfahrzeuge GmbH
Priority date: 2019-06-25
Filing date: 2020-06-15
Publication date: 2022-05-04
Also published as: JP2022538268A; JP7305809B2; WO2020260048A1; CN114007921B; DE102019117019A1; CN114007921A

Abstract

The invention relates to a method for the dynamic optimization of a braking distance of vehicles, in particular of rail vehicles, to a device for carrying out the method, and to a computer program product which carries out the method in automated fashion in order to improve reproducibility of a braking distance of vehicles. Here, using a vehicle speed (v_ist) and an acceleration (a_ist) acting on the vehicle, at different calculation times, the method compares a nominal braking distance (s_n) under ideal conditions with an actually expected braking distance (s_a). In order to be able to still attain the originally predefined braking distance in the event of deviations, the setpoint value of the deceleration is if necessary adapted following the calculation times.

Description

METHOD AND DEVICE FOR DYNAMIC OPTIMIZATION OF A BRAKING DISTANCE OF

VEHICLES,

ESPECIALLY OF RAIL VEHICLES

The invention relates to a method for the dynamic optimization of a braking distance of vehicles, in particular of rail vehicles, a device for

Implementation of the method and a computer program product which

Executes procedure automatically. One of the essential safety aspects of vehicles of all types is theirs

Braking behavior. In rail vehicles, the adhesion between rail and wheel is of particular importance. This can change quickly and drastically due to external circumstances such as climatic conditions, which makes both the prediction and the reproducibility of braking distances significantly more difficult.

A so-called deceleration control is often used here, which sets the total braking force applied to the wheels to a predetermined setpoint. This is able, for example, to tolerances of the coefficient of friction

To compensate for the friction brake. However, if the specified setpoint value cannot be maintained over the entire braking period due to external influences, for example due to a reduced frictional connection between rail and wheel, the braking distance is extended accordingly. This is also the case if, when braking to a stopping point of the vehicle, a slight adhesion between wheel and rail is detected and then

Anti-slip measures, such as sanding the rails, can be carried out. Although the improvement in the frictional connection between wheel and rail achieved in this way can ensure that the target deceleration is subsequently achieved again, the braking in the period with a reduced frictional connection (see Fig. 1) leads to a lower deceleration and consequently to a longer one Total braking distance. Braking is therefore generally subject to scatter, the causes of which can only be partially compensated with conventional delay controls.

Negative consequences of this are, for example, that the vehicle is not at the

desired end position comes to a halt, which can result in delays and a loss of comfort for the passengers, especially in traffic networks where precise target braking is required (for example at train stations with platform screen doors).

In these cases, ATO (automatic train operation) systems are used, which aim to bring the train to a standstill as precisely as possible. However, these systems have the disadvantage that you need special precautions on the infrastructure, for example to detect the position.

It is therefore the object of the invention to provide a method with which a high reproducibility of braking distances can be achieved. This applies to both short-term and long-term impairments during a

Braking, for example due to external influences such as temporary loss of braking force or temporary deviations when correcting faults. The reproducibility of the braking distance should be given on any route section without having to take precautions on the infrastructure.

This object is achieved with a method according to the main claim, a device and a Com puterprogramm product according to the independent claims. Advantageous embodiments of the invention are described in the subordinate claims.

The method for optimizing the braking distance of a rail vehicle has a sequence of steps. Will a braking with a set

_{Target deceleration} a _{SOii initiated} at a point in time to, this is initially recorded by the system for optimizing the braking distance. Subsequently, both the actual speed of the vehicle v, _st and the acceleration a, _st actually acting on the vehicle between the time to and a subsequent time t determined. The _{target deceleration} a _SOii is not fixed at a constant value, but as a rule corresponds to a non-constant course.

A nominal braking distance s _n and an expected real braking distance s _{a are then} calculated. The nominal braking distance s _n is the braking distance that is required to move the vehicle from the point at which the brake is _triggered at time to to the desired _deceleration a _SOii acting on the vehicle

Decelerate top speed. It is possible to record the nominal braking distance s _n in two parts. The first part is the nominal braking distance s _ni already covered up to the current point in time t, while the other part represents the nominal braking distance s _n2 still to be achieved. The total nominal _{braking distance} s _{n is} calculated from the predefined setpoint _deceleration a _SOii and the actually recorded speed of the vehicle vo at the point in time when the brake is applied to. The course of the predefined setpoint _deceleration a _SOii can for example be given by a function which is dependent on the time, the speed of the vehicle and / or the location at which the vehicle is located. However, it can also be a constant function.

The expected real braking distance s _a can also be divided into two sections. On the one hand in the real previous braking distance s _ai from the time to of the start of braking to the calculation time t and on the other hand in the remaining real remaining braking distance s _a2 to be expected from the calculation time t until the time when the desired final speed is reached. The real previous braking distance s _ai is derived from the determined speed profile v, _st in one

The braking interval is determined between the times to and the calculation time t.

Possible deviations between the real braking distance and the nominal braking distance during braking can arise for various reasons. Among other things, the causes for this can be traced back to non-optimal coefficients of friction, for example in the case of disc brakes between brake shoes and disc, or reduced adhesion between wheel and rail. In the next step, the real braking distance s _a2 still to be achieved is formulated as a calculation formula as a function of the modified setpoint deceleration a _S oii, mod to be determined. The modified target deceleration a _S oii, mod can be used as a

parameter-dependent function can be formulated. It can depend on the target deceleration a _S oii, the time, the speed of the train and the location. The

Parameters determine the form of the target deceleration curve, i.e. how much is braked in different areas of the braking.

The next step is to minimize the difference between the theoretical nominal braking distance s _n and the actual braking distance s _a to be expected at time t with the aim of determining the modified target deceleration. To do this, the

Formulation for the real braking distance s _a2 still to be achieved depending on the modified setpoint deceleration a _S oii, mod inserted into a formula for the total real braking distance s _a to be expected (s _a = s _ai + s _a2 ). A possibility of minimization is to equate the theoretical nominal braking distance s _n and the actually expected real braking distance s _{a in} order to eliminate the difference between the two variables. Both the nominal braking distance s _n and the real one to be expected

Braking distance s _a (see above) are made up of a distance already covered and a distance that has yet to be achieved, with the remaining braking distance s _{a2 of} the real braking distance to be expected being the only variable

Is part of the equation and can be influenced by the choice of a future modified target deceleration. Thus, a modified target deceleration a _S oii, mod can be determined for the period after time t as a function of the target deceleration a _SO ii, which accounts for any discrepancy between the real braking distance s _ai already _traveled and the nominal braking distance s _ni already traveled in the further course of the Braking compensates, so that the entire nominal braking distance s _n

can be adhered to.

In the case described above, that the modified target deceleration by a

parameter-dependent function is formulated, the parameters of the function are determined during the minimization in such a way that the deviation between the real braking distance s _a and the nominal braking distance s _{n is} as small as possible. The last method step includes a repetition of the procedure from the method step which includes the determination of the actual deceleration a, _st acting on the vehicle and the actual speed profile of the vehicle v, _st . The distance between the repetitions and thus the distance from

Braking intervals is determined by a time interval At, which in turn is defined as the interval between the times to, t, t + At, etc. The time t + At of the current calculation step is used for the next calculation as the time t etc.

The modified setpoint deceleration a _S oii, mod thus determined is then transmitted to a device which calculates the brake pressure required to achieve the modified setpoint deceleration and then adapts the braking.

In an advantageous embodiment of the invention, the position of the vehicle is also determined, for example via a satellite-supported positioning system.

This enables the position of the brake release and the

Target end position of the vehicle up to which braking is to be ended and the vehicle has the desired speed. The _{target deceleration} a _SOii between the two named positions can be calculated using these two position _details and the speed of the train vo when the brake is applied.

In a further advantageous embodiment, the _{target deceleration} a _SOii can be _determined by the vehicle driver or a higher-level system, for example an "automatic train operation" system. In this embodiment, the target end position of the vehicle, the specified target deceleration and the

Speed of the vehicle before the position at which the braking must be triggered can be calculated at the first point of the brake release.

The deviation of the modified setpoint deceleration a _S oii, mod from the setpoint deceleration a _SO ii can preferably only be selected within certain, predefined limits in order to prevent a loss of comfort or even an unnecessary risk to passengers. The limitation can be specified both absolutely and relative to the setpoint or it can depend on other state variables. Furthermore, the individual setpoint decelerations a _SO ii of the respective braking intervals are preferably selected in such a way that the compensation for a deviation of the

Braking takes place from the desired course of braking within a specified time window. It can thus be ensured that the course of the modified setpoint deceleration a _S oii, mod differs from the setpoint decelerations a _SO ii only within defined limits. This also has the advantage that it is possible to react better to any deviations that may follow later in the braking process at the given point in time, since this reduces the risk of individual deviations from different braking intervals adding up.

In a further advantageous embodiment, to calculate the

_{Nominal braking distance} s _n at time t, preferably instead of _{target deceleration} a _SOii , _uses a reference _deceleration a _ref , which is determined via a reference model, for example a physical model. One advantage of this embodiment is that the use of a reference model takes into account the dynamic behavior of the train and brake system and thus significantly improves the accuracy of the calculation of the nominal braking distance s _n by taking real physical restrictions into account when calculating the nominal braking distance s _n .

Furthermore, an embodiment is preferably provided in which im

Method step (E) additionally a difference between the modified

Target deceleration a _S oii, mod and the target deceleration a _SO ii is calculated at time t and is also included in the deceleration control in order to further improve it.

In an advantageous embodiment of the invention, at least one deceleration sensor and / or a speed signal of the vehicle is used to determine the acceleration a, _st actually acting on the vehicle in method step (B). The use of such sensors or signals enables a comparatively simple and reliable detection of the acceleration ais _t .

In a further embodiment of the invention, the speed v, _{st of} the vehicle is used at a calculation time for determining the real braking distance s _a based on the speed of the vehicle vo at the start of braking, which is updated by means of the recorded actual deceleration a, _st up to time t. The speed v, _st is thus calculated from the speed of the vehicle vo at the start of braking and the detected deceleration a, _st .

In a further advantageous embodiment of the invention, the actual speed profile v, _st for determining the real braking distance s _{a is} measured on the vehicle using suitable speed sensors. The measured one

The speed curve is referred to below as Vist.gem.

Furthermore, in an advantageous embodiment of the invention, the method steps following the first method step, that is to say the detection of a braking, are carried out with a time offset from the first method step.

In a further advantageous embodiment of the invention, the determined speed profile v, _{st is} used to formulate the remaining braking distance s _a2 .

In a further advantageous embodiment of the invention, the set

_{Setpoint deceleration} a _SOii for determining the nominal _{braking distance} s _{n is} a function of time and / or speed and / or location, or is constant.

In an advantageous embodiment of the invention, to calculate the remaining real braking distance s _a2, the deviation between the nominal braking distance s _n and the expected real braking distance s _a is set equal to zero. This approach provides a way of minimizing the discrepancy between the

Nominal braking distance s _n and the real braking distance s _a .

The device that is required to carry out the method has the following components: a sensor system to record speed and acceleration data of the vehicle for method step (B), a memory unit to store the data recorded by the sensor system or other data, a Computing unit to process the stored data, a communication unit to receive data and commands necessary for the method, an operating interface to ensure that the device is operated by the vehicle driver and

To be able to output information.

Furthermore, a computer program product is configured to carry out the method according to one of claims 1 to 15 in an automated manner.

The invention is explained in more detail below with reference to figures. Show it:

FIG. 1 shows a delay-time diagram which is used to explain the

Delay control according to the state of the art is used.

FIG. 2 shows a delay-time diagram which is used to explain the

Delay control of the invention is used.

FIG. 3 shows a speed-time diagram which is used to explain the

Delay control of the invention is used.

Figure 4 flow diagram of an embodiment of an inventive

Delay control "stopping distance control"

FIG. 5 shows a delay-time diagram for explaining the reference delay

3ref.

Figure 6 embodiment for implementing the invention

Method in a braking system of a vehicle

FIG. 7 comparison of three different simulated delays over time for three different scenarios.

FIG. 8 Another exemplary embodiment for implementation in a braking system of a vehicle FIG. 9 Another exemplary embodiment for implementation in a braking system of a vehicle

1 shows a course of a deceleration a as a function of the time t, as it would occur in the case of deceleration controls according to the prior art when braking. Two graphs are shown in the diagram. One represents the setpoint specification a _S0 n for the deceleration (continuous line), while the other (dashed line) shows the course of the deceleration a, s _t that actually occurs. When building up the delay, it should be observed that the actual course follows the setpoint course until the specified end value of the

Target deceleration is reached. Furthermore, a drop in the actually measured deceleration can be seen, the course of the measured deceleration a, _st subsequently being adapted again to the setpoint course a _SOii .

Such a drop in the measured deceleration a, s _t is due to a section of lower adhesion, for example between wheel and rail. This in turn can, for example, be due to adverse external conditions such as wet leaves on the

Rails or a lubricating film formed by dust and moisture. The fact that the measured delay a, _st adapts _itself again to the setpoint _curve a _SOii following the drop, as can be seen in FIG. 1, could have several reasons. For example, the area of lower adhesion could only occur very locally or measures to improve the adhesion, such as sanding the rails, could be used that

Improve the frictional connection between the wheel and the rail again and thus enable the specified target deceleration again.

However, it should be noted that the use of adhesion-improving measures, due to the mostly slightly delayed onset and the existing reaction times, also causes a brief drop in the frictional connection between the wheel and the

Rail cannot prevent. A lengthening of the braking distance is therefore inevitable in such a case, provided that the target value of the deceleration is not adjusted. Because of this, there is a need for improved regulation of the

Delay as the invention proposes to justify. In contrast to FIG. 1, FIG. 2 shows a profile of a delay a as a function of time t, as would be the case with a regulation of the delay according to the invention. Here, too, it can be observed that the measured deceleration a, _st lags behind the target deceleration a _SO ii until the predetermined constant target value of the deceleration is reached. Likewise, a decrease in the measured delay due to poor adhesion can be observed as in FIG. 1. However, in FIG. 2 there is a further delay in addition to the known constant nominal curve

Identify the target course using the dotted line. This represents the setpoint curve a _S oii, mod of the delay modified by the regulation according to the invention and changes due to the decreasing measured actual delay ais _t . As can be seen, the delay of the modified setpoint curve a _S oii, mod becomes greater during the decrease in the actual delay a, _st . After the frictional connection between wheel and rail has been normalized, the actual deceleration a, _st adapts to the setpoint curve a _S oii, mod and a greater deceleration of the vehicle can be achieved. As a result, an area of lower deceleration can be compensated for and the originally intended braking distance can also be achieved despite a temporary drop in the actual deceleration.

Figure 3 shows another diagram to illustrate the effect of

delay control according to the invention. The diagram shown shows the relationship between a speed of the vehicle and the time t or a _{target deceleration} a _SOii and an actual deceleration a, _st and the time t. It is divided into two areas that are defined by a current calculation time.

Before the time of the calculation, the vehicle is braked with a actually measured deceleration a, _st , shown in dashed lines, which results from a set _{target deceleration} a _SOii (continuous line). It can be seen here that the specified target value is not reached by the actually measured actual deceleration and, for example, due to changing adhesion coefficients between

Rail and wheel is not constant. The one that occurs during braking

The speed curve (dashed line) is measured by sensors and is set based on the curve of the actual deceleration. After the calculation time t, a change in the gradient of the speed graph can be seen. The changing slope can be justified by the modified setpoint deceleration a _S oii, mod shown in dash-dotted lines. This was calculated by the method according to the invention and is greater than the previous setpoint deceleration a _SO ii before the calculation time. This is due to the fact that the previous real delay from the previous one

Target deceleration has deviated. In order to be able to maintain the nominal braking distance s _n , which would have been set with an optimal braking without a deviation of the actual deceleration from the target deceleration, the modified target deceleration a _S oii, mod must therefore be greater than the previous target deceleration. It should be noted that the

Graphs of the modified setpoint deceleration a _S oii, mod and the speed profile after the calculation time t merely represent calculated values. To the

Calculation time t is therefore assumed in this case that after the calculation time t the modified setpoint deceleration a _S oii, mod remains constant. If this is not the case, it will not be shown at a later date

Calculation time consequently the calculation of the target deceleration with the

updated values and thus the target deceleration further adjusted.

FIG. 4 shows an embodiment of a basic sequence according to the invention for calculating the modified delay curve a _S oii, mod. Based on

For example, a reference deceleration a _re f is first determined by the vehicle driver or a higher-level system externally specified target deceleration a _SO ii. This step is necessary because in practice, due to the inertia of the brake system, for example due to the build-up of the pneumatic brake pressure, it is impossible to apply the required deceleration value from one point in time to the other. Therefore, a realistic deceleration curve must be determined for the calculation of the nominal braking distance s _n . This represents the

Reference delay a _re f.

The difference between the _{setpoint deceleration} a _SOii and the reference _deceleration a _{ref is} shown in FIG. 5. This shows a further diagram in which a deceleration is plotted over time. The courses of a _{target deceleration} a _SOii and a Reference delay a _ref shown. While the _{target deceleration} a _{SOii suddenly} assumes a constant target value from the value 0, the graph of the

Reference delay a _ref only gradually increases, slowly approaches the constant setpoint and consequently only reaches it later. So he's running the real one

_{Target deceleration} a _SOii after.

In addition to the specification of the _{setpoint deceleration} a _SOii , the measurements of the actually effective deceleration a, _st and the speed v, _{st are also} fed to the system from FIG. After determining the reference delay a _ref from the

_{Setpoint deceleration} a _SOii , the nominal _{braking distance} s _{n is} determined on the basis of the reference deceleration a _ref and the speed vo when the braking is triggered, which is therefore part of the speed profile v, s _t . In addition, the for

expected real braking distance s _a from the detected actual deceleration a, s _t and the speed vo determined. Both the nominal braking distance s _n and the expected real braking distance s _a are composed of two parts of the route. On the one hand from the distance covered s ^ and on the other hand from the still to

yielding route S2. The sections are determined as follows:

• Covered nominal braking distance:

s _ni = f (a _ref , v ₀ ) = fv ₀ + ff a _ref (t) (1)

If it is not possible to determine a reference delay a _ref because, for example, there is no suitable physical model on the basis of which a determination can be carried out, instead of the reference delay a _ref, the

_{Target deceleration} a _{SOii inserted} directly into equation (1) above. Real braking distance covered:

(a) based on the speed vo at the start of braking and the recorded

Delay a, _st

Sal = f ( ^a is _> VQ) = fv ₀ + ff a _is (t) (2)

(b) or based on the measured speed (Vj _S t _{, g} em)

• Nominal remaining braking distance to be achieved:

s _U 2 = f (a _should , v (t)) = v (t) ² / 2a _should (4)

Where v (t) is the measured speed Vis _t .gem or that calculated on the basis of the measured acceleration a, _st and the speed vo at the start of braking

Speed v _{is caic} (t) = v ₀ + / a _is (t) can be. Real remaining braking distance to be achieved:

s _{a 2} = setpoint specification until the end of braking as

Result of the brake optimization (5)

Where v (t) is the measured speed v, _st or that calculated on the basis of the measured acceleration a, _st and the speed vo at the start of braking

Speed v _{is caic} (t) = v ₀ + / a _is (t) can be.

The deviation e between the nominal and the expected braking distance is thus:

® ^ aΐ S _a 2 ^ nl ^ n2 (®)

Due to the fact that the aim of the method is to achieve reproducibility of the braking distances as precisely as possible, the deviation e is minimized. In the embodiment shown in FIG. 4, it is set equal to zero for this purpose. Of the 4 partial routes, only the real remaining braking distance s _a 2 still to be achieved can be influenced by a suitable choice of the deceleration curve. In this way, the expected real remaining braking distance s _a 2 and, in turn, a modified setpoint deceleration a _S oii _, mo _d can be calculated. This can be done using the expression of the real

Remaining braking distance s _a 2 (equation 5) can be inserted into the above-described equation of the deviation (equation 6). In addition, the deviation a _d ei _t a between the new target deceleration a _S oii _, mo _d and the _{target deceleration} a _{SOii is} determined. This can then serve as a further input variable for the delay control.

After a time interval At between times t and t + At, which defines a braking interval, the method is repeated and the nominal braking distance s _n and the expected real braking distance s _a for the time t + At are newly determined. Corresponds to the real one Braking distance s _a the nominal braking distance s _n , applies to the modified setpoint deceleration asoii.mod: modified setpoint deceleration a _S oii, mod equals setpoint deceleration a _SO ii. The

Target deceleration a _SO ii is therefore retained. If this is not the case, a further modified setpoint deceleration a _S oii, mod is calculated. This happens until the vehicle has reached the desired top speed. If the vehicle is to be braked to a standstill, ie the desired final speed equal to 0, then in practice the correction of the target deceleration is terminated at a speed close to 0. For the case mentioned at the beginning of the train entering a train station with platform screen doors, in which a particularly precise folding of the train is important, the correction is canceled as late as possible in order to ensure an exact folding position of the vehicle. The time t + At of the previous calculation step becomes the new time t for each calculation step.

FIG. 6 represents a first exemplary embodiment and shows how the method according to the invention could be implemented together with deceleration control of a vehicle. The method, referred to here as "Stopping Distance Controller", uses the procedure explained in FIG. 4 to determine a modified setpoint specification a _S oii, mod from the originally specified setpoint deceleration a _SO ii and the deceleration ai _st actually acting on the vehicle up to the point in time _. The modified setpoint specification a _S oii, mod can - similar to the input value a_soll - be both a constant value and a dynamic setpoint profile of the delay.

Like the measured actual deceleration, the modified setpoint specification then represents an input parameter for the deceleration control of the vehicle. Based on the actually measured acceleration, the

Delay control determines the delay a _S oii, ctrl. The braking forces (Fi, F2, ...) and their distribution are calculated from this manipulated variable of the deceleration control. The "Stopping Distance Controller" as well as the deceleration control and the calculation of the braking forces are part of the train's electronic brake control. The data obtained in this way are ultimately implemented using appropriate actuators. The resulting acceleration a, _st and der

Speed curve v, _st are in turn determined by the corresponding Vehicle sensors detected and sent to the "stopping distance controller" or the

Delay regulation for the subsequent calculation returned.

FIG. 7 shows a comparison of various simulated delay profiles for 3 different scenarios. In each of the three scenarios, a braking distance for the same vehicle is made up of one for all for different framework conditions

Simulated scenarios at the same speed. The respective delay curves are shown in the three different delay-time diagrams in FIG.

A system with delay control is assumed here.

As can be seen from the table in FIG. 7, in scenario A the adhesion over the entire braking period is 100%. There are therefore ideal conditions, since the frictional connection between the wheel and the rail does not occur at any point during braking

is reduced and thus there is no slip between wheel and rail. The

The actual deceleration curve a, _st in the diagram for scenario A is consequently constant on the _{target deceleration run} a _SOii , if one _disregards a small difference in building up the constant deceleration value. The vehicle can thus be braked with the constant target deceleration over the entire braking period. The resulting braking distance for the vehicle is 800m. Due to the

In this scenario, the use of the "Stopping Distance Control" (SDC) according to the invention does not bring any advantages in ideal conditions. Therefore, this scenario can be viewed as a reference scenario for the other two.

Scenario B, on the other hand, deviates from the ideal conditions, since the adhesion occurs in one area (approx. From second 5 to 12), for example due to adverse external conditions

Conditions at only 90%. There is thus a slight slip between the wheel and the rail for this period, in which consequently the _{target deceleration} a _SOii cannot be achieved by the actual deceleration a, _st . The method according to the invention is also not used in scenario B (SDC inactive), so that the braking distance is extended from 800 m in reference scenario A to 817 m.

In scenario C, the SDC is finally active, while the adhesion in the range between approx. 5 and 12 seconds is only 90% as in scenario B. As in the diagram of the To recognize scenario C, the setpoint specification is in response to the

Partial section reduced adhesion increased for the rest of the braking. As a result, the actual value of the deceleration, as soon as the subsection with the reduced adhesion has been passed, follows the setpoint and is therefore braked with a greater deceleration. As a result, the vehicle comes to a stop after 800m and was thus able to achieve the same braking distance as in reference scenario A despite a section with reduced adhesion.

In summary, the invention relates to a method for dynamically optimizing a braking distance of rail vehicles, a device for performing the method and a Com puterprogramm product which automatically executes the method in order to improve the reproducibility of a braking distance of rail vehicles. The procedure is the same using the measured one

Vehicle speed v, _st and the acceleration a, _st acting on the vehicle are below a nominal braking distance s _n at different calculation times

Ideal conditions with an actually expected braking distance s _a ab. In order to be able to continue to achieve the originally specified braking distance in the event of deviations, the desired value of the deceleration is adjusted after the calculation times.

REFERENCE CHARACTERISTICS a delay

3 is actually the deceleration acting on the vehicle (actual deceleration) a _SOii predetermined _{target deceleration}

3ref reference delay

3set, modified modified setpoint deceleration

3delta difference between modified and specified target deceleration

Vist determined speed curve

Vist, like measured speed curve

Vist.calc from the speed at the start of braking and the measured deceleration

calculated speed profile (calculated speed profile)

Vo speed when braking is triggered

to time of brake release

Sn nominal braking distance

Sa actual braking distance

t time of calculation

t + At point in time following time t

At period between time to and time t

Claims

PATENT CLAIMS

1. A method for optimizing the braking distance of a vehicle, comprising the following procedural steps:

(A) Determination of braking with a specific _target deceleration (a _SOii ) at the point in time (to),

(B) determining a deceleration actually acting on the vehicle (ais _t ) and an actual speed profile (vis _t ) of the vehicle between times (to) and (t),

(C) Determination of a nominal braking distance (s _n ) of the vehicle from a

set _{target deceleration} (a _SOii ) and the actually recorded

Speed of the vehicle (vo) at the time (to) of the brake release,

(D) Calculation of a real previous braking distance (s _ai ) at time t based on the determined speed profile (vj _St ),

(E) Formulation of a remaining real remaining braking distance (s _a 2) as a function of a modified target deceleration (a _S oii, mod)

(F) Determination of the modified target deceleration (a _S oii, mod) of the vehicle for future braking after the calculation time by minimizing the difference between the nominal braking distance (s _n ) and the expected real braking distance (s _a ),

(G) Repetition of process steps (C) to (F) at defined time intervals (At) between times (to) and (t) until the desired one

Final speed of the vehicle.

2. The method according to any one of the preceding claims, wherein the modified target deceleration (a _S oii, mod) is a parameter-dependent function depending on the time and / or the speed and / or the location, and / or is constant and the modified target deceleration ( a _S oii, mod) is determined in method step (F) by determining the parameters of the function.

3. The method according to the preceding claim, wherein the _{target deceleration} (a _SOii ) is calculated from the position of the brake release and a target end position of the vehicle.

4. The method according to any one of the preceding claims, wherein the

_{Setpoint deceleration} (a _SOii ) is set by the vehicle driver or a higher-level system, in particular an "automatic train operation" system, and thus the position of the start of braking is calculated.

5. The method according to the preceding claim, wherein the limits for the modified target deceleration (a _S oii, mod) relative or absolute to the original

Target deceleration (a _SO ii) can be set.

6. The method according to any one of the preceding claims, wherein the

Target deceleration (a _S oii, mod) is chosen so that the compensation of a deviation from the target deceleration (a _SO ii) takes place in a fixed time window.

7. The method according to any one of the preceding claims, wherein for

Calculation of the nominal _{braking distance} (s _n ) instead of the _{target deceleration} (a _SOii ) a

Reference delay (a _ref ) is used, which is determined via a reference model, in particular a physical model, and takes into account the dynamic behavior of the system.

8. The method according to any one of the preceding claims, wherein in

Method step (F) additionally a difference between the modified

Target deceleration (a _S oii, mod) and the predetermined target deceleration (a _SO ii,) is calculated, which is also included in the deceleration control.

9. The method according to any one of the preceding claims, wherein the

actual speed profile (vist) in method step (B) using a

Speed (vo) at the start of braking and the actual deceleration (aist) is determined and the thus determined speed (Vist.caic) for the calculation of the real one

Braking distance (s _a ) is used in step (D).

10. The method according to any one of the preceding claims, wherein the actual speed profile (vist) is measured in method step (B) by suitable sensors on the vehicle and this measured speed profile (Vist.ge _m ) is used to determine the real braking distance (s _a ) in method step (D) is used.

11. The method according to any one of the preceding claims, wherein the method steps following method step (A) are carried out with a time offset to method step (A).

12. The method according to any one of the preceding claims, wherein for

Formulation of the remaining braking distance (s _a 2) in process step (E) the determined

Velocity curve (vist) is used.

13. The method according to any one of the preceding claims, wherein the course of the set _{target deceleration} (a _SOii ) for determining the nominal _{braking distance} (s _n ) in method step (C) is a function of time and / or speed and / or location, or is constant is.

14. The method according to any one of the preceding claims, wherein for

Calculation of the remaining real braking distance (s _a 2) the deviation between the nominal braking distance (s _n ) and the expected real braking distance (s _a ) is set equal to zero.

15. The method according to any one of the preceding claims, wherein for

Determination of the nominal braking distance (s _n ) a covered part (s _ni ) and a still to be performed part (s _n 2) of the nominal braking distance (s _n ) is determined.

16. Device for performing the method according to one of the

preceding claims, comprising:

a sensor system configured to record speed and acceleration data of the vehicle for method step (B) of claim 1, a storage unit configured to store the speed and acceleration data or other required data recorded by the corresponding sensor system,

a computing unit, configured to process the data stored in the memory unit and thus in particular to carry out method steps (C) to (F),

a communication unit configured to receive necessary data from the sensors or other communication interfaces and to communicate with other communication units for data exchange,

an operating interface configured for the driver of the vehicle

To output information and to be served by it.

17. Computer program product configured to carry out the method according to one of claims 1 to 15.