DE102019211939A1 - Method for determining a carriage speed of a carriage - Google Patents

Abstract

A method for determining a car speed (vWagen) of a car is provided, which has 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; Wheel speed (vOdo) from the speed of the at least one carriage element and a proportionality factor; and- determining the car speed (vWagen) from the wheel speed (VOdo); - in a second operating mode: - detecting an acceleration (amess) of the car; and- determining the vehicle speed (vWagen) at least from the acceleration (amess); a change from the first to the second operating mode takes place when at least one change condition is met. Furthermore, a device, a vehicle and a computer program product are provided for carrying out the method.

Description

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

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

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

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

A position determination by means of train control systems is generally only possible selectively or in sections, and is therefore not suitable for continuous evaluation.

A speed signal from the so-called anti-skid system, 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 the time, for example due to wear and tear, can be slowly changed. Further measurement inaccuracies can arise from a slip of the wheelset generated by a force transmission when braking or accelerating. With a non-driven and unbraked wheelset, the comparison or reference wheelset, measurement deviations due to the slip can be minimized, but this is associated with additional expenditure on components and during assembly or is an unbraked wheelset (e.g. due to the reduction in braking power ) not wanted.

It is true that longitudinal acceleration can be detected in a favorable manner using acceleration sensors, but the detected longitudinal acceleration must be compensated for by a portion of the acceleration due to gravity. Furthermore, acceleration sensors can exhibit a drift which, as experience shows, greatly falsifies the speeds and distances 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 determined approximately from the state variables of a drive or a brake. However, inaccuracies in the determination of these forces result, for example from ignorance of the exact coefficient of friction between the brake disc and the brake lining and an exact force application point or the non-ideal force transmission between wheel and rail.

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

The object is achieved by the subjects of the independent claims. Advantageous further developments of the invention are the subject matter of the dependent claims.

In this document, a wagon is a component of a train which can in particular be coupled to other wagons or which has degrees of freedom with respect to the rest of the train. For example, it can be a wagon or a part of a multiple unit that is articulated to another part. In contrast, 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
  • - Determining the car speed from the wheel speed;
• - in a second operating mode:
  • - Detecting an acceleration of the car; and
  • - Determining the car speed at least from the acceleration; in which

a change from the first to the second operating mode takes place 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 transmission ratio and / or another factor which is designed to convert the detected speed into a peripheral speed of the wheel to determine which is preferably used as the wheel speed.

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

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

The acceleration can particularly preferably be detected from a highly precisely aligned uniaxial sensor, or the sensor system has further 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 takes place if a low quality of the wheel speed can be determined or is determined (e.g. by comparison with a reference speed formed). The reference speed is explained in more detail below.

The wheel speed is preferably of poor quality if 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 locks, that is, when the wheel cannot completely transfer the applied drive or braking torque to a surface on which the wheel rolls. A car speed can then no longer be reliably determined from the wheel speed determined therefrom, so that a change is made to the second operating mode in which the car speed is essentially determined from the detected acceleration.

The quality of the wheel speed is preferably determined as a characteristic value. Its determination is preferably designed in such a way that the characteristic value changes to a value which corresponds to a poorer quality when a braking intervention takes place. Alternatively or in addition, there is a change in the characteristic value to a value which corresponds to a poorer quality when a slide protection intervention takes place. As an alternative or in addition, 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 poorer quality if a high torque is impressed on 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 certain 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 in which the car is driven or braked.

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

The reference speed is preferably formed in such a way that from drive and / or brake variables, preferably from all drive and / or brake variables, in particular from drive and / or braking forces that act on the carriage or the wheel, the speed of which is detected, a theoretical speed of the car, precisely the reference speed, is formed, whereby it is assumed that the drive and / or braking forces are optimally transferred to the rail. 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 also taken into account when determining the reference speed. The inertia from the mass of the car is preferably taken into account. In addition, a rotatory one is particularly preferred Inertia of rotating elements of the car, such as the wheels, are taken into account.

The quality of the determined wheel speed can thus advantageously be determined purely from a comparison of the reference speed with the actual wheel speed. If the car is driven with excessive drive force, the wheels threaten to skid. So they would spin faster than the carriage 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 force, the wheels threaten to lock. So they would turn more slowly 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 speed and the reference speed. If the difference is small or even equal to zero, the wheel speed is close to the actual speed of the car or it corresponds completely to it. Alternatively or additionally, a percentage deviation or some other 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 comparison with individual wheel speeds.

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

As an alternative or in addition, it is conceivable that the second operating mode can be defined in such a way that the wheel speed is also used here in addition to the detected acceleration to determine the vehicle speed. This is preferably done when the quality of the wheel speed has decreased, so that the second operating mode has already been changed, but the quality is still in a predetermined quality range, so that a certain deviation of the wheel speed from the car speed can be expected is, but these can be equalized in particular by additional calculations. Thus, a wheel speed determined in this way can advantageously be used to supplement the determination of the vehicle speed in the second operating mode or for its plausibility check.

The method proposed here makes it possible to combine the advantages of two types of determination of the carriage speed via a sensor fusion, e.g. by dynamic weighting and averaging of both signals. An error occurring as a result of a drift when determining the vehicle 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.

Preferably, the steps of 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 rotational speed or the specific wheel speed can thus 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 car is continuously available, so that when changing to the second operating mode, the speed of the car can be determined immediately, in particular by means of integration.

As a result, the variables of the rotational speed of the at least one carriage element, wheel speed and / or acceleration of the carriage are advantageously also available in the other operating mode.

Alternatively or in addition, a further step is provided in which a change from the second to the first operating mode or a stay in the first operating mode takes place if no change condition is met. This ensures that the vehicle speed is always determined after 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 rotational speed of the carriage element is zero and the carriage is therefore stationary.

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

Alternatively or additionally, the at least one change condition is the application of a drive or braking torque to the wheel. For this purpose, the magnitude of the torque particularly preferably exceeds a limit value.

The vehicle speed is preferably determined in the second operating mode by integrating the detected acceleration or an acceleration derived therefrom.

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

Alternatively or additionally, the vehicle speed is determined in the second operating mode, taking into account the wheel speed, in particular by correcting the wheel speed. The wheel speed is then preferably used further in the second operating mode when the quality of the determined wheel speed has indeed 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 car speed is carried out taking into account the wheel speed and the acceleration of the car. This can preferably be done with a control observer, particularly preferably with a Kalman filter.

A value of the wheel speed, preferably the most recently determined value of the wheel speed in the first operating mode, is preferably used as the integral start value for the integration. This ensures that the integrated speed value is calculated on the basis of an integral start value that has been determined as error-free as possible.

• - ein Bremsdruck und/oder eine Zuspannkraft einer Bremse, die zur Bremsung des Rades ausgebildet ist;
• - ein Strom und/oder eine Spannung einer Vorrichtung, die dazu ausgebildet ist, dem Rad ein Moment aufzuprägen;
• - 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 method preferably has a further step in which a parameter is determined which is designed to evaluate a quality of the determined reference speed, the parameter being formed in particular 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 current and / or a voltage of a device which is designed to impress a torque on the wheel;
• - a driving or braking torque applied to the wheel;
• - A weight of the car, which is determined by a load detection;
  • - the detected 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 an anti-slip intervention is present;
  • - Information as to whether there is a braking intervention;
  • - 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 in particular pneumatically, hydraulically, electrically and / or mechanically generate the application force of the brake.

The device, which is designed to apply a torque to the wheel, can preferably be designed as a motor that can apply the 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 are also included in these devices. It can also be contactless braking devices, such as eddy current brakes.

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 moment that is applied to the wheel. If the detected acceleration corresponds to an acceleration expected for an applied moment, it can be assumed that the moment is completely supported in the wheel contact point on the surface on which the wheel is rolling. So there is no or only very little slip. On the other hand, it is the detected acceleration different, preferably less than expected in the case of an applied moment, it can be assumed that the complete moment in the wheel contact point is not supported 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.

The 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 carriage speed; in the case of a braked wheel, it is lower. Values for wheel slip are also calculated in the anti-skid, for example, so that these values are available in a car.

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

Dabei ist v_Odo die Radgeschwindigkeit und v_Ref die ermittelte Referenzgeschwindigkeit. Weitere Möglichkeiten beide Werte zu vergleichen sind denkbar.The values determined 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 wheel speed determined 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. Further possibilities of comparing both values are conceivable.

The coefficient of friction is determined by other functions within the car, for example. 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 an applied brake pressure or current and / or voltage of a motor. The determination is preferably carried out by means of suitable model calculations.

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

As an alternative or in addition, the quality, as stated above, can also be calculated on the basis of the information whether an anti-skid intervention is present, the information whether a braking intervention is present and / or the information whether the corresponding wheel is being driven. In a simple embodiment, a table of values can be stored which assigns a quality value to corresponding information. Other calculation methods are conceivable.

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

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

The at least one change condition is preferably characterized by the parameter as exceeding or falling below a limit value.

Alternatively or additionally, a change condition is fulfilled due to incorrect detection of the speed. This can be given, for example, by a defective or incorrectly functioning detection means, with errors in the detection usually being able to be recognized 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 last determined carriage speed;
• - At least one variable which 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 a quality of the determined wheel speed is assessed differently depending on environmental conditions or the current vehicle speed. If, for example, the car speed is used, a higher quality of the determined wheel speed can be required at high car speeds than at low car speeds, so that a more precise statement about the current car speed is possible.

The determined vehicle speed, in particular the vehicle speed determined from the detected acceleration, is preferably reset to the wheel speed when the vehicle is traveling without braking or drive or when the vehicle is stationary.

In the case of an advantageous resetting of the car speed calculated from the detected acceleration of the car when driving without acceleration, i.e. if there is as little or no force influence as possible due to drive or braking forces on the wheel, an error that occurs during integration can be kept as small as possible. When driving without a drive, the influences of errors due to slip, such as skidding or sliding, can be excluded or neglected, so that a comparison or reset, which can be carried out by integrating the specific car speed with the wheel speed, and thus the car speed as possible exact value can be set.

The detected car acceleration is preferably corrected, since it may differ from the actual car acceleration. The correction is preferably carried out before the further processing of the car acceleration, in particular before the car speed is determined from the detected car acceleration. Options for correcting the car acceleration are described below.

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

The method preferably has one of the following steps:

• - determining a gradient value of a route section; and or
• - Correct the car speed taking into account the gradient value.

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

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

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

The detected acceleration is preferably corrected to a corrected acceleration by the corrective acceleration, and the carriage speed is determined from the corrected acceleration, in particular by integration. The correction is preferably carried out by subtraction or multiplication, or a combination of calculation with the portion of the correction acceleration that runs in the plane of the detected acceleration. The carriage speed is preferably determined 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 start value.

With an advantageous detection of an acceleration, 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 and the calculated carriage speed can be adapted with a factor derived from the acceleration deviation.

If the detected longitudinal acceleration is corrected by the acceleration in the vertical plane perpendicular to the longitudinal direction to a corrected longitudinal acceleration and the car speed is calculated by integrating the corrected longitudinal acceleration, a drift error in a speed value of the car speed can be in connection with the comparison of the reference speed and the car speed be kept small over the longest possible period.

The slope value or the correction acceleration are preferably 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, that is to say a change in the wheel speed over time, and the acceleration of the car.

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

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

Alternatively or additionally, the carriage 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 also 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 car, is also provided, the vehicle being designed to carry out the method according to the invention and / or the vehicle having a device according to the invention. The individual carriages of the rail vehicle are preferably coupled to one another, the coupling preferably being rigid or torque-free.

The device and / or the vehicle are preferably designed to detect the rotational speed of the carriage element and / or the acceleration of the carriage, wherein they furthermore have means to carry out the above-described method in at least one form.

According to a fourth aspect of the invention, a computer program product is also 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. There is thus advantageously the possibility of designing 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
• 4th a diagram of a calculation of a quality of the wheel speed.

1 shows a diagram of a driving state-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 by means of odometry from the speed of a wheel of the car. The speed of the wheel can be determined using pulses from a pulse generator. Alternatively, other methods of detecting the speed are also possible. The wheel speed v _Odo can then be determined over 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 and accurately determined due to the occurrence of slip and a lack of precise knowledge of the wheel radius, including due to wear. The radius r _wheel can therefore be determined again and again, for example by suitable methods, while the car is in motion. Such methods are known to the person skilled in the art from the prior art. It is therefore assumed in the following that the radius r _{wheel is} known.

In the embodiment shown, between four states "Standstill", "Coasting", " A distinction is made between driving ”and“ braking ”, which can be used to determine the vehicle speed. These states are explained below.

When the car is stationary, a driving state in which the wheel speed v _{Odo is} zero, the car speed v _wagon corresponds to the wheel speed v _Odo , in accordance with the first operating mode described above. Since the wheels are not turning, the wheel speed v _{Odo is} zero. In addition, an integral _{starting value} v _{0, acc is} determined. This is set equal to the value of the wheel speed v _Odo and is therefore also zero. All velocities v _Odo , v _{0, acc} and v _Wagen take on the value zero.

If the car is now driven by means of a moment that is applied to the wheel, the determination of the car speed changes to the "Drive" state. Since slippage of the driven wheel cannot be ruled out due to the applied torque, a correlation between the detected wheel speed and the actual vehicle speed is no longer mandatory.

The car speed v _car is now calculated according to the second operating mode as follows: A measured acceleration a _{mess of} the car is integrated over the elapsed time. Then, by adding the result of the integration in the elapsed time and the integral start value v _{0, acc} at the beginning of the elapsed time, the car speed v _{car is} calculated.

If no moment is impressed on the wheel while the car is in motion, the car rolls freely in one direction of travel. In this case, the determination of the carriage speed is in the "Coasting" state. Since no or only minimal slip occurs here, inaccuracies due to the slip can be neglected. The car speed v _car is determined here, corresponding to the first operating mode, by the wheel speed v _Odo . The integral _{starting value} v _{0, acc is also set} equal to the wheel speed v _Odo .

Basically, the determination of the wagon speed v _wagon in the coasting state corresponds to that in the stationary state.

If the car is now decelerated by means of a moment applied to the wheel, the determination of the car speed changes to the "braking" state. Since slippage of the driven wheel cannot be ruled out due to the applied torque, it is no longer certain that the determined wheel speed corresponds to the actually present car speed v _car .

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 thus given in that a distinction is only made between two states, namely “standstill / coasting” and “driving / braking”. This is 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 switched to the non-powered driving state (coasting), both the car speed v _wagon and the integral _{starting value} v _{0, acc} equated with the wheel speed v _Odo . The integral start value v _{0, acc} can be the last determined value of the wheel speed v _Odo , which was determined before the change 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, that is to say 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, with a correction of the detected acceleration a _mess taking place here by means of the correction acceleration a _correction . For this purpose, the determined correction acceleration a _{correction is} subtracted from the detected acceleration a _mess . The result of this difference is then integrated. The further determination of the carriage speed v _carriage is over with the determination 1 identical and need no further explanation.

The correction of the car speed v _car is carried out by taking into account a gradient value of a route section. Alternatively or additionally, deviations due to other disturbance variables are also corrected or no correction is carried out.

For the correction using the gradient value of the route section, a Correction _acceleration a _korr perpendicular to the carriage, that is, recorded in a direction perpendicular to a longitudinal axis of the carriage in a vertical plane. Alternatively, the gradient value of the route section is recorded in some other way or a topology of the route is used to determine the gradient value. In this way, the influence of a gradient can be eliminated in the detected acceleration a _mess .

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 detected acceleration a _{mess can} also be corrected by accelerations in other planes.

3 shows a diagram of a third embodiment of the method according to the invention. The determination of the carriage speed v _carriage takes place according to the method steps from 1 and 2 . The method shown here differs from the previously shown method in that it only changes between two states.

If the wheel of the car is driven or braked, with a torque being impressed on the wheel for this purpose, the car speed v _{car is determined} by means of integration. The method is thus in the second operating state according to the invention. If no moment is impressed on the wheel of the wagon, the wagon is in the free rolling state “coasting” or it is at a standstill. Then the carriage speed v _{carriage is determined} by means of odometry, i.e. by equating the carriage speed v _carriage with the wheel speed v _Odo . The method is thus in the first operating state according to the invention.

Switching between the individual states takes place in the procedures described in 1 to 3 are shown by the condition of 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”). A change between these states can, however, also be brought about in other ways. 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.

4th FIG. 13 is a diagram of a calculation of a quality of the wheel speed.

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 to the left into the calculation block B. The calculation block B finally outputs the quality Q of the wheel speed v _Odo on its right-hand side.

The input value Q1 comes from a calculation block that represents a basic value calculation. On the basis of one or more parameters P1 that 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 an 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, which specifically processes parameters P2 from the wheel slide protection of the car. If, for example, the anti-skid function of the car is triggered, the input value Q2 is changed accordingly, so that the calculation block B then outputs a characteristic value which corresponds to a poorer quality Q.

Another input value Q3 originates from a calculation _{block which} processes the wheel speed v _Odo and a reference speed v _Ref as input variables. For example, a minimum slip can be determined from the comparison of the wheel speed v _Odo with the reference speed v _Ref , which, compared to the carriage, would result in zero slip and with ideal power transmission between wheel and rail. Such a minimum slip can then be given to calculation block B as input value Q3. However, the input value Q3 can also be an abstract value.

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

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

In addition, embodiments for calculating quality are conceivable which only processes part 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 “stationary”, a driving condition 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 equated to the current wheel speed v _Odo . Further, the car speed v of the wheel speed v _{cart Odo} is set equal, so that all the velocities v _Odo, v _0, v _acc and so _coach take the same value, in particular zero, to. In addition, the longitudinal acceleration a may _{be measured,} the correction acceleration a _correction determined directly in this state on the determined measured value.

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 Differenz der Fahrzeugbeschleunigung ermittelt aus der Referenzgeschwindigkeit v_Ref und der gemessenen Fahrzeugbeschleunigung a_mess bestimmt werden.
2. 2. Wenn Schlupf vorhanden ist:
   • 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.

If the driving state changes from "standstill" to a driven driving state ("driving"), in which the local _car speed v _wagon increases, the local wagon speed v _wagon is calculated as follows:

1. 1. If there is no significant slip:
   • 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 a _correction can be determined from the difference between the vehicle acceleration determined from the reference speed v _Ref and the measured vehicle _acceleration a _mess .
2. 2. If there is slippage:
   • When the drive or braking controller detects significant slip, so if the quality of the wheel speed v _Odo falls below a predetermined value, the measured longitudinal acceleration a _mess of the car by means of the previously determined correction acceleration a _correction corrected and integrated over the elapsed time. Then, by adding the result of the integration in the elapsed time and the integral start value v _{0, acc} at the beginning of the elapsed time, the local car speed v _{car is} calculated.

When the driving state changes from the driven driving state to a non-driven driving state, a so-called “coasting”, both the local vehicle speed v _Wagen and the integral starting value v _{0, acc are set} to the wheel speed v _Odo .

If no or only minimal slip occurs in the case of coasting, the carriage speed v _carriage can still be determined by equating it with the wheel speed v _Odo . Inaccuracies due to the minimal slip can be neglected.

When the driving state changes from the unpowered driving state to a braked driving state (“braking”), the local _vehicle speed v _{wagon is determined} analogously to the driving state “driving” using the above-mentioned case distinction. If there is little or no slip, the car speed v _{car is set} equal to the wheel speed v _Odo . Is not negligible slip is present, the car speed v _cars from the integration of the measured longitudinal acceleration a _mess, which was the correction acceleration a _correction corrected is determined.

In cases in which the rail vehicle is braked to a standstill (“standstill”), or the speed is only reduced without stopping completely and then switched to the non-powered driving state (“coasting”), both the local wagon speed v _wagon and the integral _{starting value} v _{0, acc} 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 route section 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, in this way it is also possible to determine the speeds of vehicles that are composed, for example, of at least two cars, the cars being either rigidly connected or connected to one another via couplings. In this way, local speeds of individual cars can be determined and these can optionally also be used to determine a global speed of the entire vehicle.

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

QUOTES INCLUDED IN THE DESCRIPTION

This list of the documents listed by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 0499947 A1 [0021]

Claims (16)

Method for determining a carriage speed (v _carriage ) of a carriage with the following steps: in a first operating mode: detecting a speed of at least one carriage element, the rotational speed of which is directly proportional to the rotational 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 car speed (v _car ) from the wheel speed (v _Odo ); - In a second operating mode: - Detecting an acceleration (amess) of the car; and - determining the car speed (v _car ) at least from the acceleration (a _mess ); wherein there is a change from the first to the second operating mode when at least one change condition is met. Procedure according to Claim 1 wherein the steps of - detecting a speed of at least one carriage element, the speed of which is directly proportional to the speed of at least one wheel of the carriage; and / or - determining a wheel speed (v _Odo ) from the rotational 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 , wherein 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 car speed (v _car ) in the second operating mode takes place by integrating the detected acceleration (a _mess ) or an acceleration derived therefrom, a value preferably being used as the integral starting 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 car speed (v _car ) in the second operating mode taking into account the wheel speed (v _Odo ), in particular by correcting the wheel speed (v _Odo ). Method according to one of the preceding claims, comprising a further step: determining a quality of the determined wheel speed (v _Odo ), the quality preferably being formed as a characteristic value taking into account at least one of the following variables: a brake pressure and / or a brake application force which is designed to brake the wheel; a current and / or a voltage of a device which is designed to impress a torque on the wheel; - a driving or braking torque applied to the wheel; - a weight of the car, which is determined by a load detection - 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 detected acceleration (a _mess ); - a driving or braking torque applied to the wheel; - a global vehicle speed; - Information as to whether an anti-slip intervention is present; - Information as to whether there is a braking intervention; - Information as to whether the corresponding wheel is being driven. Procedure according to Claim 5 , wherein the at least one change condition is fulfilled as exceeding or falling below a limit value through the quality, in particular through the characteristic value. Procedure according to Claim 6 , 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 the wheel speed (v _Odo ) or a wheel acceleration is compared with a reference variable and the fulfillment of the at least one change condition is determined on the basis of the comparison, the reference variable preferably describing a target behavior of the car and particularly preferably as Reference speed (v _Ref ) or is designed as a reference acceleration. Method according to one of the preceding claims, wherein the at least one change condition is the application of a drive or braking torque to the wheel, and / or is characterized as incorrect detection of the speed. A method according to one of the preceding claims, wherein the predetermined car speed (v _cars), in particular certain of the detected acceleration (Amess) carriage speed (v _cars), in a braking or driving without driving or stoppage of the carriage on the wheel speed (v _Odo ) is reset. Method according to one of the preceding claims, with the steps of: - determining or detecting an incline 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 gradient value (α) preferably being determined from the correction acceleration (a _correction ). Procedure according to Claim 11 , the gradient value (α) or the correction acceleration (a _correction ) being detected gyroscopically, and / or the gradient value (α) being determined from a comparison of the wheel speed (v _Odo ) and a speed determined by integrating the acceleration (a _mess ) , and / or wherein the gradient value (α) is determined from a comparison of a wheel acceleration and the acceleration (amess), and / or wherein the gradient value (α) or the correction acceleration (a _correction ) is determined on the basis of a determined position of the car on the route section become. Procedure according to Claim 12 , the car speed (v _car ) or the detected acceleration (amess) being corrected taking into account the gradient value (α); and / or wherein the carriage speed (v _carriage ) or the detected acceleration (amess) is corrected by the correction acceleration (a _correction ). Device for determining a carriage speed (v _carriage ) of a carriage, which is designed to perform the method according to one of the Claims 1 to 13 perform. Vehicle, in particular rail vehicle, having at least one carriage, the vehicle for performing the method according to one of the Claims 1 to 13 is formed, and / or wherein the vehicle is a device according to Claim 14 having, wherein the carriage is preferably track-bound, in particular designed as a rail vehicle or part of a rail vehicle. Computer program product with code means which are stored on a machine-readable carrier and which have a data processing device, preferably a device according to Claim 14 to initiate the procedure according to one of the Claims 1 to 13 to be carried out when the code means are executed on the data processing device.

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