DE102019211939B4 - Method for determining a carriage speed of a carriage - Google Patents

Abstract

Method for determining a carriage speed (v carriage) of a carriage with the steps: - in a first operating mode: - detecting a speed of at least one carriage element whose speed is directly proportional to the speed of at least one wheel of the carriage; - determining a wheel speed (vOdo) from the Speed of the at least one carriage element and a proportionality factor; and- determining the carriage speed (vcarriage) from the wheel speed (VOdo);- in a second operating mode:- detecting an acceleration (amess) of the carriage; and- determining the car speed (vcar) at least from the acceleration (amess); wherein- a change from the first to the second operating mode occurs when at least one change condition is met; and having a further step: - determining a quality of the determined wheel speed (vOdo), wherein the quality is determined as a characteristic value taking into account a current and / or a voltage of a device that is designed to impose a torque on the wheel, and wherein the at least one Alternating condition as exceeding or falling below a limit value is fulfilled by the characteristic value.

Description

The invention relates to a method for determining a carriage speed of a carriage, and in particular to a method for determining the carriage speed of a carriage of a rail vehicle. The invention further relates to a device, a vehicle and a computer program product for carrying out the method.

Precise knowledge of a position, a speed and a deceleration or acceleration of rail vehicles is the basis for a variety of possibilities for improving operational processes in rail vehicle traffic.

However, measured variables that are measured directly with reasonable effort to determine the position, speed and deceleration or acceleration are in many cases subject to large measurement errors.

When determining a position using satellites, namely using a global satellite navigation system (GNSS), such as GPS, Galileo or GLONASS, the true position is superimposed on a mean-free measurement noise, the standard deviation of which can be estimated from the number of satellites received. However, if the reception situation is poor, the accuracy can be drastically reduced or reception can fail completely, for example in a tunnel.

Position determination using train control systems is generally only possible at certain points or in sections and is therefore not suitable for continuous evaluation.

A speed signal from the so-called anti-skid, which is either provided by a reference wheel set, or is determined over several or all wheel sets, for example dynamically weighted, has the problem that a systematic measurement inaccuracy is caused by a wheel diameter that is not exactly known, which extends over can be caused by slow changes over time, for example due to wear and tear. Further measurement inaccuracies can arise from wheel set slip caused by power transmission during braking or acceleration. A non-driven and unbraked wheel set, the comparison or reference wheel set, can minimize measurement deviations due to slip, but this involves additional effort in terms of components and assembly or is an unbraked wheel set (e.g. due to the reduction in braking power ) not wanted.

Although it is possible to detect longitudinal acceleration inexpensively using acceleration sensors, the detected longitudinal acceleration must be compensated for by a gravitational acceleration component. Furthermore, acceleration sensors can exhibit a drift, which experience shows greatly distorts speeds and paths determined from integration or even makes them unusable.

A braking or acceleration force that results in a change in the speed of the car can be approximately determined from state variables of a drive or a brake. However, inaccuracies arise when determining these forces, for example due to ignorance of the exact coefficient of friction between the brake disc and the brake pad and the exact point of force application or the non-ideal power transmission between the wheel and the rail.

The DE 10 2007 044 195 A1 relates to a method and a system with a means for accurately determining the speed of a vehicle. An initial estimate of the vehicle's speed is calculated based on rotation rates of a plurality of wheels on the vehicles. When one of the wheels on the vehicle is in a brake control or traction control situation, the initial estimate is modified based on acceleration of the vehicle to produce a modified estimate of the vehicle's speed.

The DE 10 2015 000 931 A1 relates to a method for determining a reference speed for a vehicle with at least two wheels as an estimate of the actual speed for determining wheel slip in a driving dynamic control situation. The vehicle comprises a longitudinal acceleration sensor for determining a longitudinal acceleration in the longitudinal direction when the vehicle is traveling straight ahead and a wheel speed sensor on each of the at least two wheels for determining a wheel speed. The method includes the following steps: a) Continuously determining the wheel speed v _rad1/2 on the at least two wheels and comparing the respective wheel acceleration a _rad1/2 with a predetermined threshold value S1, whereby the respective wheel blocks when the threshold value S1 is exceeded, and where If at least one wheel is blocked, the method is continued with step b); b) determining the longitudinal acceleration a of the vehicle; c) determining an estimated value x = [v _ref , Δa]; and d) correcting the estimate x = [v _ref , Δa] with a measurement of the wheel speed of the locked wheel v _rad/1 if one of the following conditions is met: aa) the estimate is v _ref smaller than the measured wheel speed v _rad/1 of the blocking wheel; bb) vehicle standstill or a _rad/1 > S2 or v _rad/1 local maximum; or correcting the estimated value x = [v _ref , Δa] with a measured value for the wheel speed of the at least one further wheel v _rad/2 if its wheel slip is between 0 and a further predetermined threshold value for the wheel slip S3, above which the wheel blocks.

The DE 102 60 416 A1 relates to a method and a system for determining the speed of a vehicle, in which the speed (n ₁ -n ₄ ) of at least one wheel of the vehicle is detected by means of corresponding speed sensors (S1-S4) and the speed (v) of the vehicle, based on the detected speed of the at least one wheel is determined by means of an evaluation and control device (C). In addition, the acceleration of the vehicle is recorded using suitable acceleration sensors (S5-S6) and the speed (v 1 -v ₄ ) determined from the speed (n _{1 -n 4} ) of the at least one wheel is determined by the evaluation and control device (C ), based on the recorded acceleration, checked and corrected if necessary.

The DE 195 27 531 A1 relates to a vehicle speed determining system that can determine a reference vehicle speed of an all-wheel drive vehicle when all wheels are slipping or locking. An integration value of a longitudinal acceleration is forcibly used to determine the reference vehicle speed when the vehicle is accelerated and a change in a lowest wheel speed is negative or when the vehicle is braked and a change in a highest wheel speed is positive.

The invention is therefore based on the object of creating an improved possibility for determining a carriage speed.

The task is solved by the subjects of the independent claims. Advantageous developments of the invention are the subject of the dependent claims.

In this document, a wagon is a component of a train that can in particular be coupled to other wagons or that has degrees of freedom compared to the rest of the train. For example, this can be a wagon or part of a multiple unit that is articulated to another part. However, a separate rail vehicle, such as a locomotive, can also be referred to as a wagon.

• - in einem ersten Betriebsmodus:
  • - Erfassen einer Drehzahl mindestens eines Wagenelementes dessen Drehzahl direkt proportional mit der Drehzahl mindestens eines Rades des Wagens ist;
  • - Bestimmen einer Radgeschwindigkeit aus der Drehzahl des mindestens einen Wagenelementes und einem Proportionalitätsfaktor; und
  • - Bestimmen der Wagengeschwindigkeit aus der Radgeschwindigkeit;
• - in einem zweiten Betriebsmodus:
  • - Erfassen einer Beschleunigung des Wagens; und
  • - Bestimmen der Wagengeschwindigkeit zumindest aus der Beschleunigung;

wobei
ein Wechseln vom ersten in den zweiten Betriebsmodus erfolgt, wenn zumindest eine Wechselbedingung erfüllt ist.According to the invention, a method for determining a carriage speed of a carriage is provided with the following steps:

• - in a first operating mode:
  • - Detecting a speed of at least one car element whose speed is directly proportional to the speed of at least one wheel of the car;
  • - Determining a wheel speed from the speed of the at least one carriage element and a proportionality factor; and
  • - Determine the car speed from the wheel speed;
• - in a second operating mode:
  • - Detecting an acceleration of the car; and
  • - Determine the car speed at least from the acceleration;

where
A change from the first to the second operating mode occurs when at least one change condition is met.

The carriage element is preferably a wheel, an axle of the carriage or a shaft of a motor of the carriage, the proportionality factor preferably being a wheel radius, a gear ratio and/or another factor which is designed to determine a peripheral speed of the wheel from the detected speed to determine which is preferably used as the wheel speed.

The speed is preferably recorded using conventional means, in particular with a speed sensor or pulse generator.

The acceleration is preferably recorded using conventional means, in particular with acceleration sensors, which are preferably designed in the form of a MEMS (microelectromechanical systems) and are usually used in an inertial measuring system.

The acceleration can particularly preferably be detected from a highly precisely aligned uniaxial sensor, or the sensor system has additional sensors in orthogonal spatial directions and can be corrected using a calibration method.

The at least one change condition is preferably defined in such a way that a change from the first to the second operating mode occurs when a low quality of the wheel speed (for example by comparison with a reference formed speed) can be detected or is detected. The reference speed is explained in more detail below.

A low quality of the wheel speed is preferably given when the detected speed or the wheel speed determined therefrom does not correlate with the actual vehicle speed and/or deviates from a reference value, such as a reference speed. This is particularly the case when the wheel skids or stalls, i.e. when the wheel cannot fully transfer applied drive or braking torque to a surface on which the wheel is rolling. A carriage speed can then no longer be reliably determined from the wheel speed determined from this, so that a change is made to the second operating mode, in which the carriage speed is essentially determined from the detected acceleration.

The quality of the wheel speed is determined as a characteristic value. Its determination is preferably designed in such a way that the characteristic value changes to a value that corresponds to a poorer quality when a braking intervention takes place. Alternatively or additionally, the characteristic value changes to a value that corresponds to a poorer quality when an anti-skid intervention takes place. Alternatively or additionally, the characteristic value is changed to a value that corresponds to a poorer quality if a deviation of the detected wheel speed from the reference speed exceeds or falls below a predetermined value. Alternatively or additionally, the characteristic value is changed to a value that corresponds to a poorer quality if a high torque is applied to the corresponding wheel, which results in high driving forces in the wheel-rail contact, which in turn cause the wheel to slip.

The characteristic value of the quality is preferably determined in such a way that, starting from a specific carriage speed, in a state in which the carriage rolls freely, i.e. is neither driven nor braked, it assumes a value that corresponds to a higher quality, compared to states at which the car is driven or braked.

In a particular embodiment, a reference speed is determined according to the method described in the EP 0 499 947 A1 is disclosed (reference speed of the anti-skid).

The reference speed is preferably formed in such a way that its speed is recorded from drive and/or braking variables, preferably from all drive and/or braking variables, in particular from drive and/or braking forces that act on the car or the wheel, a theoretical speed of the car, i.e. the reference speed, is formed, whereby it is assumed that an optimal transmission of the driving and / or braking forces to the rail takes place. This means that the reference speed corresponds to a theoretically possible speed of the car if the corresponding wheel does not slip or skid. The influence of the inertia of the car is taken into account when determining the reference speed. The inertia from the mass of the car is preferably taken into account. It is also particularly preferred to take into account the rotational inertia of rotating elements of the car, such as the wheels.

The quality of the determined wheel speed can advantageously be determined purely from a comparison of the reference speed with the actual wheel speed. If the car is driven with too much driving force, the wheels risk skidding. So they would rotate faster than the car's inertia would allow. In this case, the wheel speed would be higher than the corresponding reference speed. If the car is braked with excessive braking forces, the wheels risk locking. So they would turn slower than the car's inertia would allow, because the car's inertia keeps “pushing” the wheels. In this case, the wheel speed would be lower than the corresponding reference speed. In both cases, a quality of the wheel speed can be determined by forming a difference between the amounts of the wheel and reference speed. If the difference is small or even zero, the wheel speed is close to or completely equal to the actual speed of the car. Alternatively or additionally, a percentage deviation or another possibility of comparing the wheel speed with the reference speed can also be provided.

The reference speed can also preferably be formed from at least two of the determined wheel speeds. The reference speed is preferably suitable for identifying implausible wheel speeds or a low quality of a wheel speed by comparing them with individual wheel speeds.

Furthermore, it is also conceivable to use several reference speeds that are determined in different ways.

Alternatively or additionally, it is conceivable to design the second operating mode in such a way that here too the wheel speed is used in addition to the detected acceleration to determine the carriage speed. This preferably happens when the quality of the wheel speed has decreased, so that a change has already been made to the second operating mode, but the quality is still in a predetermined quality range, so that a certain deviation of the wheel speed from the carriage speed can be expected is, but these can be equalized in particular through additional calculations. A wheel speed determined in this way can advantageously be used to supplement the determination of the carriage speed in the second operating mode or to check its plausibility.

The method proposed here makes it possible to combine advantages of two types of determination of the carriage speed via sensor fusion, e.g. by dynamic weighting and averaging of both signals. An error that occurs due to drift when determining the carriage speed, preferably when determining by integrating the detected acceleration, can preferably be kept as small as possible by such a correction with the wheel speed.

The quality as a characteristic value is determined taking into account a current and/or a voltage of a device that is designed to impose a torque on the wheel. The at least one changing condition is characterized as the parameter exceeding or falling below a limit value.

The device, which is designed to apply a torque to the wheel, can preferably be designed as a motor that can apply drive and/or braking torque to the wheel. Brakes that develop their braking effect by supporting the applied braking torque at the wheel contact point also belong to these devices. These can also be non-contact braking devices, such as eddy current brakes.

Preferably, the steps are detecting a speed of at least one car element, the speed of which is directly proportional to the speed of at least one wheel of the car and / or determining a wheel speed from the speed of the at least one car element and a proportionality factor; also carried out in the second operating mode. The speed or the specific wheel speed can be continuously evaluated and, in particular, a change to the first operating mode can be triggered on the basis of this evaluation.

Alternatively or additionally, the step of detecting an acceleration of the car is also carried out in the first operating mode. The acceleration of the carriage is therefore continuously available, so that when switching to the second operating mode, the carriage speed can be determined immediately, in particular by means of integration.

This advantageously means that the speed of the at least one carriage element, wheel speed and/or acceleration of the carriage are also available in the other operating mode.

Alternatively or additionally, a further step is provided in which a change from the second to the first operating mode or remaining in the first operating mode takes place if no change condition is met. This ensures that the carriage speed is always determined according to the first operating mode as long as no change condition is met.

The method is preferably carried out in the first operating mode when the detected speed of the carriage element is zero and the carriage is therefore stationary.

The detected acceleration is preferably a longitudinal acceleration in the direction of travel of the car. This acceleration is therefore advantageously suitable for determining a speed in a direction of travel of the car. Alternatively or additionally, the longitudinal acceleration can also be determined from an acceleration that is not recorded directly in the longitudinal direction. This can be done, for example, by converting the recorded acceleration using trigonometric relationships.

Alternatively or additionally, the at least one changing condition is an application of a drive or braking torque to the wheel. Particularly preferably, the amount of the torque exceeds a limit value.

Preferably, the carriage speed is determined in the second operating mode by integrating the detected acceleration or an acceleration derived therefrom.

The carriage speed calculated from the acceleration of the carriage, which is calculated by integrating the detected acceleration, is also advantageously free of any Phase shift and not susceptible to mean-free error components in the acceleration measurement (e.g. interference caused by vibration).

Alternatively or additionally, the carriage speed is determined in the second operating mode taking the wheel speed into account, in particular by correcting the wheel speed. The wheel speed is preferably continued to be used in the second operating mode if the quality of the determined wheel speed has decreased, so that the method has changed to the second operating mode. However, the quality is still within a predetermined range, so that it can be used in particular to correct the determined speed from the detected acceleration of the car. In this case, a determination of the carriage speed is carried out taking into account the wheel speed and the acceleration of the carriage. This can preferably be done with a control observer, particularly preferably with a Kalman filter.

Preferably, a value of the wheel speed, preferably the last determined value of the wheel speed in the first operating mode, is used as the integral start value for the integration. This ensures that the integrated speed value is calculated based on an integral starting value that is determined as accurately as possible.

• - ein Bremsdruck und/oder eine Zuspannkraft einer Bremse, die zur Bremsung des Rades ausgebildet ist;
• - einem auf das Rad aufgebrachten Antriebs- oder Bremsmoment;
• - eine Gewichtskraft des Wagens, welche durch eine Lasterfassung ermittelt wird;
• - die erfasste Beschleunigung des Wagens;
• - ein Radschlupf des Rades;
• - die Referenzgeschwindigkeit und/oder die Wagengeschwindigkeit;
• - einer globalen Fahrzeuggeschwindigkeit.
• - ein Reibwert zwischen dem Rad und einer Oberfläche auf der das Rad rollt;
• - eine Information, ob ein Gleitschutzeingriff vorliegt;
• - eine Information, ob ein Bremseingriff vorliegt;
• - eine Information, ob das entsprechende Rad angetrieben oder abgebremst wird.

The quality is preferably determined as a characteristic value taking into account at least one of the following variables:

• - a brake pressure and/or an application force of a brake which is designed to brake the wheel;
• - a drive or braking torque applied to the wheel;
• - a weight of the car, which is determined by a load measurement;
• - the recorded acceleration of the car;
• - a wheel slip of the wheel;
• - the reference speed and/or the carriage speed;
• - a global vehicle speed.
• - a coefficient of friction between the wheel and a surface on which the wheel rolls;
• - information as to whether there is an anti-skid intervention;
• - information as to whether a braking intervention has occurred;
• - Information as to whether the corresponding wheel is being driven or braked.

The brake is preferably designed as a friction brake. Different designs are conceivable, which generate the application force of the brake in particular pneumatically, hydraulically, electrically and/or mechanically actuated.

If the detected acceleration is used to evaluate the quality of the determined wheel speed, it can preferably be used to determine the effect of a torque that is applied to the wheel. If the detected acceleration corresponds to an acceleration expected for an applied torque, it can be assumed that the torque is completely supported at the wheel contact point on the surface on which the wheel rolls. So there is no or very little slip. However, if the detected acceleration is different, preferably lower, than expected for an applied torque, it can be assumed that the complete torque is not supported at the wheel contact point on the surface on which the wheel rolls. This is particularly the case when the coefficient of friction between the surface on which the wheel rolls and the wheel decreases, so that the full moments and forces can no longer be supported. In addition, a slope correction of the detected acceleration is preferably carried out. This is explained in detail below.

Wheel slip is usually defined as the deviation between an actual vehicle speed and the peripheral speed of a wheel. In the case of a driven wheel, the peripheral speed of the wheel is greater than the speed of the car; in the case of a braked wheel, it is smaller. Values for wheel slip, for example, are also calculated in anti-skid protection so that these values are available in a car.

oder $$\left|{\text{v}}_{\text{Odo}}/{\text{v}}_{\text{Ref}}\right|$$

The determined values for the reference speed can preferably themselves be used to determine a minimum wheel slip, or they can allow a statement to be made about the quality of the determined wheel speed by means of a comparison. Such a comparison can preferably be designed as follows: $$\left|{\text{v}}_{\text{Odo}}-{\text{v}}_{\text{Ref}}\right|$$

or $$\left|{\text{v}}_{\text{Odo}}/{\text{v}}_{\text{Ref}}\right|$$

Here v _Odo is the wheel speed and v _Ref is the determined reference speed. Other ways to compare both values are conceivable.

For example, the coefficient of friction is determined within the car by other functions. If such a coefficient of friction is available, it can also be evaluated accordingly.

The drive or braking torque applied to the wheel can be determined, for example, from variables such as applied brake pressure or current and/or voltage of a motor. The determination is preferably carried out using suitable model calculations.

A global vehicle speed is to be understood in particular as a speed which represents the speed of a vehicle consisting of at least two cars. This can be determined, for example, from a navigation system or by averaging or summarizing individual local car speeds.

Alternatively or additionally, the quality, as listed above, can also be calculated based on the information as to whether there is an anti-skid intervention, the information as to whether there is a braking intervention, and/or the information as to whether the corresponding wheel is driven. In a simple embodiment, a table of values can be stored that assigns a quality value to corresponding information. Other calculation methods are conceivable.

Taking at least one of these variables into account means that a statement can be made about the correlation of the detected speed of a carriage element with the existing carriage speed and thus a statement about the quality of the determined wheel speed.

The parameter, which in particular reflects the quality described above, can be formed in different ways. The parameter is preferably determined taking one of the above-mentioned variables into account. However, several variables, preferably weighted differently, can also be combined into one parameter.

A change condition can also be fulfilled by incorrectly recording the speed. This can be the case, for example, due to a defective or malfunctioning detection means, where errors in the detection can usually be detected by the vehicle's own diagnostic functions.

• - einer Temperatur, vorzugsweise einer Umgebungstemperatur;
• - einer Feuchtigkeit, vorzugsweise einer Feuchtigkeit der Oberfläche auf der das Rad rollt;
• - einer Wagengeschwindigkeit, vorzugsweise der zuletzt bestimmten Wagengeschwindigkeit;
• - zumindest einer Größe, welche die physikalische Plausibilität des Sensorsignals charakterisiert und somit Werte, die durch ein fehlerhaftes Sensorsystem erzeugt werden erkennt.

The limit value is preferably designed to be variable and is varied in particular taking into account one of the following variables:

• - a temperature, preferably an ambient temperature;
• - moisture, preferably moisture of the surface on which the wheel rolls;
• - a carriage speed, preferably the most recently determined carriage speed;
• - at least one variable that characterizes the physical plausibility of the sensor signal and thus recognizes values that are generated by a faulty sensor system.

It can thus advantageously be achieved that the quality of the determined wheel speed is evaluated differently depending on environmental conditions or the current vehicle speed. If, for example, the carriage speed is used, a higher quality of the determined wheel speed can be required at high carriage speeds than at low carriage speeds, so that a more precise statement about the current carriage speed is possible.

Preferably, the specific carriage speed, in particular the carriage speed determined from the detected acceleration, is reset to the wheel speed when driving without brakes or drive or when the carriage is at a standstill.

If the vehicle speed calculated from the detected acceleration of the vehicle is advantageously reset when driving without acceleration, i.e. if there is as little or no force influence as possible due to driving or braking forces on the wheel, an error that occurs during integration can be kept as small as possible. When driving without a drive, error influences due to slip, such as skidding or sliding, can be excluded or neglected, so that an adjustment or a reset of the carriage speed determined by the integration to the wheel speed can take place, and thus the carriage speed to as much as possible exact value can be set.

The detected vehicle acceleration is preferably corrected since it may have a deviation from the actual vehicle acceleration. The correction is preferably carried out before further processing of the car acceleration, in particular before determining the car speed from the detected car acceleration gung. Options for correcting the car acceleration are described below.

• - Bestimmen eines Steigungswerts eines Streckenabschnitts; und/oder
• - Korrigieren der Wagengeschwindigkeit unter Berücksichtigung des Steigungswerts.

Preferably the method has one of the following steps:

• - Determining a gradient value of a section of route; and or
• - Correcting the carriage speed taking into account the gradient value.

If an incline value of a route section is advantageously determined and the car speed is corrected taking the incline value into account, the car speed calculated from the acceleration can be calculated more precisely.

Preferably, the carriage has a longitudinal direction, and the slope value is detected by detecting a correction acceleration in a direction perpendicular to the longitudinal direction in a vertical plane.

The acceleration of the car in its vertical direction is preferably determined. If the car travels at a constant speed, this speed is higher on the level than on an incline due to the direct weight of the car. This allows a gradient value to be determined. Particularly preferably, other values can also be taken into account when determining the gradient in this way. For example, the actual carriage speed also has an influence on the correction acceleration. This can be noticed, for example, when driving over a hill or driving through a depression.

Preferably, the detected acceleration is corrected to a corrected acceleration by the correction acceleration, and the carriage speed is determined from the corrected acceleration, in particular by integrating. The correction is preferably carried out by subtracting or multiplying, or a combination of offsetting with the portion of the correction acceleration that runs in the plane of the detected acceleration. The determination of the carriage speed is preferably carried out by integrating the acceleration corrected in this way, with a value of the wheel speed, as described above, particularly preferably being used as the integral starting value.

When an acceleration is advantageously detected, preferably in a direction perpendicular to a longitudinal direction of the carriage in a vertical plane, an acceleration deviation resulting from this acceleration can be compensated for and the calculated carriage speed can be adjusted with a factor arising or derived from the acceleration deviation.

When the detected longitudinal acceleration is corrected to a corrected longitudinal acceleration by the acceleration in the vertical plane perpendicular to the longitudinal direction and the carriage speed is calculated by integrating the corrected longitudinal acceleration, in connection with the comparison of the reference speed and the carriage speed, a drift error may occur in a speed value of the carriage speed be kept small for as long as possible.

Preferably, the gradient value or the correction acceleration are recorded gyroscopically.

The gradient value can alternatively or additionally be determined from a comparison of the wheel speed and a speed determined by integrating the acceleration of the car.

The gradient value can also be determined from a comparison of a wheel acceleration, i.e. a change in the wheel speed over time, and the acceleration of the car.

The gradient value and/or the correction acceleration can ultimately also be determined based on a determined position of the car on the route section. This can be done, for example, by comparing it with digital map data, whereby the position of the car, which is usually recorded using GPS, is assigned gradient data that is stored in the map data.

The car is preferably designed as part of a vehicle consisting of at least one car.

Alternatively or additionally, the car is track-bound, in particular designed as a rail vehicle or part of a rail vehicle.

According to a second aspect of the invention, a device for determining a carriage speed of a carriage is further provided, which is designed to carry out the method according to the invention. This is preferably an electronic data processing device, such as a control device, which can particularly preferably be installed in a car.

According to a third aspect of the invention, a vehicle, in particular a rail vehicle, in particular having at least one carriage, is further provided, wherein the vehicle is designed to carry out the method according to the invention, and/or wherein the vehicle has a device according to the invention. The individual cars of the rail vehicle are preferably coupled to one another, with the coupling preferably being designed to be rigid or torque-free.

The device and/or the vehicle are preferably designed to detect the speed of the carriage element and/or the acceleration of the carriage, and they also have means for carrying out the method described above in at least one form.

According to a fourth aspect of the invention, a computer program product is further provided with code means which are stored on a machine-readable carrier and which cause a data processing device, preferably a device according to the invention, to carry out the method according to the invention when the code means are executed on the data processing device. It is therefore advantageously possible to design a device and/or a carriage for carrying out the method.

The invention will now be explained by means of an embodiment with reference to the accompanying drawings.

• 1 ein Schaubild einer ersten Ausführungsform des erfindungsgemäßen Verfahrens,
• 2 ein Schaubild einer zweiten Ausführungsform des erfindungsgemäßen Verfahrens,
• 3 ein Schaubild einer dritten Ausführungsform eines erfindungsgemäßen Verfahrens, und
• 4 ein Schaubild einer Berechnung einer Qualität der Radgeschwindigkeit.

Show it

• 1 a diagram of a first embodiment of the method according to the invention,
• 2 a diagram of a second embodiment of the method according to the invention,
• 3 a diagram of a third embodiment of a method according to the invention, and
• 4 a diagram of a calculation of a quality of the wheel speed.

1 shows a diagram of a driving condition-dependent determination of a car speed v _car of a car.

n_Rad ist dabei die Drehzahl, r_Rad ist der Radradius.A wheel speed v _Odo is determined via odometry from a speed of a wheel of the car. The speed of the wheel can be determined using pulses from a pulse generator. Alternatively, other methods for detecting the speed are also possible. The wheel speed v _Odo can then be determined via a radius of the wheel, and thus over a circumference of the wheel, and the speed of the wheel. This can be done in particular by the following calculation: $${\text{v}}_{\text{Odo}}={\text{n}}_{\text{wheel}}\times {\text{r}}_{\text{wheel}}$$

n _wheel is the speed, r _wheel is the wheel radius.

The wheel speed v _Odo cannot always be reliably determined due to slip that occurs and the wheel radius not being precisely known, among other things due to wear. The wheel radius r _wheel can therefore be determined again and again, for example, using suitable methods while the car is moving. Such methods are known to those skilled in the art from the prior art. Therefore, it is assumed below that the wheel radius r _Rad is known.

In the embodiment shown, a distinction is made between four states “standstill”, “coasting”, “driving” and “braking”, in which the carriage speed can be determined. These states are explained below.

When the car is at a standstill, a driving state in which the wheel speed v _Odo is zero, the car speed v _car , corresponding to the first operating mode described above, corresponds to the wheel speed v _Odo . Since the wheels do not rotate, the wheel speed v _Odo is zero. In addition, an integral starting value v _0,acc is determined. This is equated to the value of the wheel speed v _Odo and is therefore also zero. All velocities v _Odo , v _0,acc and v _car therefore take on the value zero.

If the car is now driven by means of a torque applied to the wheel, the determination of the car speed changes to the “drive” state. Since slipping of the driven wheel cannot be ruled out due to the applied torque, a correlation between the recorded wheel speed and the actual vehicle speed is no longer necessarily given.

The carriage speed v _carriage is now calculated, according to the second operating mode, as follows: A measured acceleration a _mess of the carriage is integrated over the elapsed time. Then, by adding the result of integration in the elapsed time and the integral starting value v _0,acc at the beginning of the elapsed time, the carriage speed v _carriage is calculated.

If no moment is applied to the wheel while the cart is in motion, the cart will roll freely in one direction. In this In this case, the determination of the carriage speed is in the “Coasting” state. Since no or only minimal slip occurs here, inaccuracy due to slip can be ignored. The carriage speed v _carriage is determined here, in accordance with the first operating mode, by the wheel speed v _Odo . Likewise, the integral starting value v _0,acc is equated to the wheel speed v _Odo .

Essentially, the determination of the wagon speed v _wagons in the coasting state corresponds to that in the standstill state.

If the car is now decelerated by means of a torque applied to the wheel, the determination of the car speed switches to the “braking” state. Since slipping of the driven wheel cannot be ruled out due to the torque applied, it is no longer certain that the determined wheel speed corresponds to the actual vehicle speed v _wagon .

The carriage speed v _carriage is now calculated analogously to the determination in the driving state, according to the second operating mode described above.

The states of standstill and coasting on the one hand and the states of driving and braking on the other hand differ only in the forces or moments applied to the wheel or wheels that are used to determine the wheel speed v _Odo . A further embodiment is therefore provided in that a distinction is only made between two states, namely “standstill/coasting” and “driving/braking”. This will be in 3 shown, which will be discussed in more detail later.

In cases in which the rail vehicle is braked to a standstill, or the speed is merely reduced without stopping completely and then changed to the unpowered driving state (coasting), both the carriage speed v _carriage and the integral starting value v _0,acc equated with the wheel speed v _Odo . The integral starting value v _0,acc can be the last determined value of the wheel speed v _Odo , which was determined before the changing condition occurs and the speed is determined in the second operating mode.

In a special embodiment, the acceleration a _mess is a longitudinal acceleration of the car, i.e. an acceleration along its longitudinal axis and thus an acceleration in the direction of travel.

2 shows a diagram of a second embodiment of the method according to the invention, in which the detected acceleration a _measurement is corrected by means of the correction acceleration a _correction . For this purpose, the determined correction acceleration a _correction is subtracted from the recorded acceleration a _measurement . The result of this difference is then integrated. The further determination of the wagon speed v _wagon is finished with the determination 1 identical and requires no further explanation.

The correction of the wagon speed v _wagon is carried out by taking into account an incline value of a route section. Alternatively or additionally, deviations due to other disturbance variables are corrected or no correction is carried out.

For the correction using the gradient value of the route section, a correction acceleration a _korr is recorded perpendicular to the car, i.e. in a direction perpendicular to a longitudinal axis of the car in a vertical plane. Alternatively, the gradient value of the route section is recorded in a different way or a topology of the route is used to determine the gradient value. In this way, the influence of a gradient in the recorded acceleration a _mess can be eliminated.

The carriage speed v _carriage is calculated by integrating the detected acceleration a _mess , which is corrected by the correction acceleration a _korr perpendicular to the longitudinal direction of the carriage in the vertical plane. Alternatively, the recorded acceleration a _mess can also be corrected by accelerations in other levels.

3 shows a diagram of a third embodiment of the method according to the invention. The determination of the wagon speed v _wagon is carried out in accordance with the process steps from 1 and 2 . The method shown here differs from the methods shown previously in that it only switches between two states.

If the wheel of the car is driven or braked, with a torque being applied to the wheel, the car speed v _car is determined by means of integration. The method is therefore in the second operating state according to the invention. If no moment is imprinted on the wheel of the cart, the cart is in a free-rolling “coasting” state or is at a standstill. Then the car speed v _car is determined using odometry, i.e. by equating the car speed v _car with the wheel speed v _Odo determined. The method is therefore in the first operating state according to the invention.

Switching between the individual states takes place using the procedures described in the 1 to 3 are shown by the condition as to whether a torque is applied to the corresponding wheel (when “driving” or “braking”) or whether the corresponding wheel is torque-free (when “standing still” or “coasting”). However, a change between these states can also be brought about in another way. For example, based on the quality of the wheel speed v _Odo , a decision can be made as to when the wheel speed v _Odo is unsuitable for further processing.

4 shows a diagram of a calculation of a wheel speed quality.

A calculation block B is shown, which is designed to determine a quality Q of the wheel speed v _Odo on the basis of input values Q1, Q2, Q3, Q4 which lead into the calculation block B on the left. The calculation block B finally outputs the quality Q of the wheel speed v _Odo on its right side.

The input value Q1 comes from a calculation block that represents a basic value calculation. Based on one or more parameters P1, which result from the operation of the car, a basic value for the quality Q is calculated here, which is then transmitted to the calculation block B as input value Q1. For example, a parameter P1 can simply be information as to whether there is a braking intervention, whether the corresponding wheel is being driven, or whether it is torque-free.

Another input value Q2 comes from a calculation block that specifically processes parameters P2 from the car's anti-skid protection. For example, if the anti-skid function of the cart is triggered, the input value Q2 is changed accordingly, so that the calculation block B then outputs a characteristic value that corresponds to a poorer quality Q.

Another input value Q3 comes from a calculation block that processes the wheel speed v _Odo and a reference speed v _Ref as input variables. For example, by comparing the wheel speed v _Odo with the reference speed v _Ref , a minimum slip can be determined that would occur in comparison to the car with zero slip and with ideal power transmission between the wheel and rail. Such a minimum slip can then be entered into the calculation block B as an input value Q3, for example. However, the input value Q3 can also be an abstract value.

Another input value Q4 comes from a calculation block that evaluates moments and/or forces on the wheel and uses this to determine the input value Q4. In this example, the sizes M and P are used as input variables. M represents a quantity that corresponds to a drive torque acting on the wheel, or a quantity from which the drive torque of the wheel can be determined. For example, this can be a current from an electric motor. The size P represents a size that corresponds to a braking torque acting on the wheel, or a size from which the braking torque of the wheel can be determined. For example, this can be a current from an active current brake, a brake pressure or similar. A force between rail and wheel, which corresponds to a driving or braking force, can also be determined from such a variable M, P. If the variables M, P are relatively high, an input value Q4 can be determined, which causes the calculation of a lower quality Q in the calculation block B compared to a state with lower variables M, P.

In a special embodiment, the calculation block B is designed as an addition operator, which adds the input values Q1, Q2, Q3, Q4 and thereby forms the quality Q as a sum.

The input values Q1, Q2, Q3, Q4 can also be processed in a weighted manner.

In addition, embodiments for quality calculation are conceivable that only process a portion of the input values Q1, Q2, Q3, Q4 shown here.

• Im „Stillstand“ des Wagens, einem Fahrzustand, in dem die Radgeschwindigkeit v_Odo Null oder nahezu Null beträgt, entspricht die lokale Wagengeschwindigkeit v_Wagen der Radgeschwindigkeit v_Odo und der Integralstartwert v0,acc der aktuellen Radgeschwindigkeit v_Odo gleichgesetzt. Ferner wird auch die Wagengeschwindigkeit v_Wagen der Radgeschwindigkeit v_Odo gleichgesetzt, so dass sämtliche Geschwindigkeiten v_Odo, v_0,acc und v_Wagen nehmen also denselben Wert, insbesondere den Wert Null, an. Zusätzlich kann jetzt in diesem Zustand über den ermittelten Messwert der Längsbeschleunigung a_mess direkt die Korrekturbeschleunigung a_korrektur bestimmt werden.

Finally, a special embodiment of the method according to the invention is described below:

• When the car is “standstill”, a driving state in which the wheel speed v _Odo is zero or almost zero, the local car speed v _car corresponds to the wheel speed v _Odo and the integral starting value v0,acc is equal to the current wheel speed v _Odo . Furthermore, the car speed v _car is equated to the wheel speed v _Odo , so that all speeds v _Odo , v _0,acc and v _car take the same value, in particular the value zero. In addition, in this state, the correction acceleration a _correction can now be determined directly using the measured value of the longitudinal acceleration a _mess .

1. 1. Wenn kein nennenswerter Schlupf vorhanden ist:
   • Wenn kein oder wenig Schlupf vorhanden ist, also wenn die Qualität der Radgeschwindigkeit v_Odo, wie oben beschrieben, einem vorbestimmten Wert entspricht:
     • Wenn in der Antriebs- bzw. Bremssteuerung kein oder nur sehr geringer Schlupf detektiert wird, so wird die Wagengeschwindigkeit v_Wagen gleich der Radgeschwindigkeit v_Odo gesetzt. Zusätzlich kann dabei die Korrekturbeschleunigung a_korrektur aus der

When the driving state changes from "standstill" to a powered driving state ("driving") in which the local _car speed vcar increases, the local _car speed vcart is calculated as follows:

1. 1. If there is no significant slippage:
   • If there is little or no slip, i.e. if the quality of the wheel speed v _Odo , as described above, corresponds to a predetermined value:
     • If no or only very little slip is detected in the drive or brake control, the carriage speed v _carriage is set equal to the wheel speed v _Odo . In addition, the correction acceleration can be a _correction from the

Difference of the vehicle acceleration determined from the reference speed v _Ref and the measured vehicle acceleration a _mess can be determined.

• Wenn die Antriebs- bzw. Bremssteuerung signifikanten Schlupf detektiert, also wenn die Qualität der Radgeschwindigkeit v_Odo unter einen vorbestimmten Wert fällt, wird die gemessene Längsbeschleunigung a_mess des Wagens mittels der vorher bestimmten Korrekturbeschleunigung a_korrektur korrigiert und über die verstrichene Zeit integriert. Dann wird durch Addition des Ergebnisses der Integration in der verstrichenen Zeit und dem Integralstartwert v_0,acc zu Beginn der verstrichenen Zeit die lokale Wagengeschwindigkeit v_Wagen berechnet.

2. If slippage is present:

• If the drive or brake control detects significant slip, i.e. if the quality of the wheel speed v _Odo falls below a predetermined value, the measured longitudinal acceleration a _mess of the car is corrected using the previously determined correction acceleration a _correction and integrated over the elapsed time. Then, by adding the result of integration in the elapsed time and the integral starting value v _0,acc at the beginning of the elapsed time, the local carriage speed v _carriage is calculated.

When the driving state changes from the driven driving state to a non-powered driving state, a so-called "coasting", both the local vehicle speed v _wagon and the integral starting value v _0,acc are set to the wheel speed v _Odo .

If in the case of “coasting” no or only minimal slip occurs, the wagon speed v _wagon can still be determined by equating it with the wheel speed v _Odo . Inaccuracies due to the minimal slip can be ignored.

When the driving state changes from the unpowered driving state to a braked driving state (“braking”), the local wagon speed v _wagon is determined analogously to the “driving” driving state using the case distinction mentioned above. If there is little or no slip, the carriage speed v _carriage is set equal to the wheel speed v _Odo . If non-negligible slip is present, the carriage speed v _carriage is determined from the integration of the measured longitudinal acceleration a _mess , which has been corrected by the correction acceleration a _correction .

In cases in which the rail vehicle is braked to a standstill (“standstill”), or the speed is merely reduced without coming to a complete stop and then changes to the unpowered driving state (“coasting”), both the local wagon speed v _wagon as well as the integral starting value v _0,acc are compared with the wheel speed v _Odo and set to the wheel speed v _Odo .

In the method described above, the correction acceleration a _correction represents the entirety of the gradient value of a section of the route and other influencing disturbance variables.

The present embodiments describe the determination of a speed of a car and thus a determination of a speed locally related to this car. However, speeds of vehicles can also be determined in this way, which are, for example, made up of at least two cars, with the cars being connected to one another either rigidly or via couplings. This allows local speeds of individual cars to be determined and, optionally, these can also be used to determine a global speed of the entire vehicle.

All features presented in the description, the following claims and the drawing can be essential to the invention both individually and in any combination with one another.

Claims (15)

Method for determining a carriage speed (v _carriage ) of a carriage with the steps: - in a first operating mode: - detecting a speed of at least one carriage element whose speed is directly proportional to the speed of at least one wheel of the carriage; - Determining a wheel speed (v _Odo ) from the speed of the at least one carriage element and a proportionality factor; and - determining the carriage speed (v _carriage ) from the wheel speed (V _odo ); - in a second operating mode: - detecting an acceleration (a _mess ) of the car; and - determining the carriage speed (v _carriage ) at least from the acceleration (a _mess ); wherein - a change from the first to the second operating mode occurs when at least one change condition is met; and comprising a further step: - determining a quality of the determined wheel speed (v _Odo ), the quality being determined as a characteristic value taking into account a current and / or a voltage of a device that is designed to impose a torque on the wheel, and wherein the at least one changing condition is fulfilled by the characteristic value as exceeding or falling below a limit value. Procedure according to Claim 1 , wherein the steps - detecting a speed of at least one car element, the speed of which is directly proportional to the speed of at least one wheel of the car; and/or - determining a wheel speed (v _Odo ) from the speed of the at least one carriage element and a proportionality factor; can also be carried out in the second operating mode, and / or wherein the step - detecting an acceleration (a _mess ) of the car; is also carried out in the first operating mode, and / or wherein a step - changing from the second to the first operating mode or remaining in the first operating mode takes place if no change condition is met and / or if the detected speed of the carriage element is zero. Procedure according to Claim 1 or 2 , where the detected acceleration (a _mess ) is a longitudinal acceleration in the direction of travel of the car. Method according to one of the preceding claims, wherein the determination of the carriage speed (v _carriage ) in the second operating mode is carried out by integrating the detected acceleration (a _mess ) or an acceleration derived therefrom, preferably as an integral start value (v _0,acc ) for the integration the wheel speed (v _Odo ), preferably the last determined value of the wheel speed (v _Odo ) in the first operating mode, is used, and/or wherein the determination of the carriage speed (v _carriage ) in the second operating mode takes into account the wheel speed (v _Odo ), in particular by correcting the wheel speed (v _Odo ). Method according to one of the preceding claims, wherein the determination of the quality is formed as a characteristic value taking into account at least one of the following variables: - a brake pressure and / or an application force of a brake which is designed to brake the wheel; - a drive or braking torque applied to the wheel; - a weight of the car, which is determined by a load measurement - a wheel slip of the wheel; - a reference speed (v _Ref ) and/or the carriage speed (V _carriage ); - a coefficient of friction between the wheel and a surface on which the wheel rolls; - the recorded acceleration (a _mess ); - a drive or braking torque applied to the wheel; - a global vehicle speed; - information as to whether there is an anti-skid intervention; - information as to whether a braking intervention has occurred; - Information as to whether the corresponding wheel is driven. Method according to one of the preceding claims, wherein the limit value is designed to be variable and is varied in particular taking into account one of the following variables: - a temperature, preferably an ambient temperature; - moisture, preferably moisture of the surface on which the wheel rolls; - the carriage speed (v _carriage ), preferably the last determined carriage speed (v _carriage ). Method according to one of the preceding claims, wherein a comparison of the wheel speed (v _Odo ) or a wheel acceleration takes place with a reference variable and the fulfillment of the at least one change condition is determined based on the comparison, the reference variable preferably describing a target behavior of the car and particularly preferably as a reference speed (v _Ref ) or is designed as a reference acceleration. Method according to one of the preceding claims, wherein the at least one changing condition is an application of a drive or braking torque to the wheel, and / or is characterized as an incorrect detection of the speed. Method according to one of the preceding claims, wherein the determined carriage speed (v _carriage ), in particular the carriage speed (v _carriage ) determined from the detected acceleration (a _mess ), when driving without brakes or drive or when the carriage is at a standstill, is based on the wheel speed (v _Odo ) is reset. Method according to one of the preceding claims, with the steps: - determining or recording a gradient value (α) of a route section; and/or - detecting a correction acceleration (a _correction ) in a direction perpendicular to a longitudinal direction of the carriage in a vertical plane, the slope value (α) preferably being determined from the correction acceleration (a _correction ). Procedure according to Claim 10 , wherein the gradient value (α) or the correction acceleration (a _correction ) are detected gyroscopically, and/or wherein the gradient value (α) is determined from a comparison of the wheel speed (v _Odo ) and a speed determined from integration of the acceleration (a _mess ). , and/or wherein the gradient value (α) is determined from a comparison of a wheel acceleration and the acceleration (a _mess ), and/or wherein the gradient value (α) or the correction acceleration (a _correction ) is based on a determined position of the car on the route section be determined. Procedure according to Claim 11 , where the carriage speed (v _carriage ) or the detected acceleration (a _mess ) is corrected taking into account the slope value (α); and/or wherein the carriage speed (v _carriage ) or the detected acceleration (a _measurement ) is corrected by the correction acceleration (a _correction ). Device for determining a carriage speed (v _carriage ) of a carriage, which is designed to use the method according to one of Claims 1 until 12 to carry out. Vehicle, in particular a rail vehicle, having at least one car, the vehicle being used to carry out the method according to one of the Claims 1 until 12 is designed, and / or wherein the vehicle has a device according to Claim 13 has, wherein the car is preferably track-bound, in particular designed as a rail vehicle or part of a rail vehicle. Computer program product with code means that are stored on a machine-readable carrier and which has a data processing device, preferably a device according to Claim 13 , cause the procedure to be carried out according to one of the Claims 1 until 12 to be carried out when the code means are executed on the data processing device.

Images