Method for stabilizing a rail vehicle

Abstract

In a method for stabilizing a rail vehicle with a wheel set, the speed of the rail vehicle is changed when a critical vibration state of the wheel set occurs. An advantageous state can be achieved if the speed of the rail vehicle is changed by using a vibration state variable of the wheel set.

Claims

1. A method for stabilizing a rail vehicle having a wheel set, which comprises the steps of: changing a speed of the rail vehicle if a critical vibration state of the wheel set occurs; changing the speed of the rail vehicle using a vibration state variable of the wheel set; and permanently reducing the speed to a predefined speed value if the critical vibration state of the wheel set occurs repeatedly.

2. The method according to claim 1, which further comprises using the vibration state variable as a controlled variable for changing the speed.

3. The method according to claim 1, wherein the vibration state variable is an acceleration running generally perpendicular to a direction of travel of the rail vehicle.

4. The method according to claim 1, which further comprises determining a maximum speed of the rail vehicle that is different from a changed speed in dependence on the changed speed.

5. The method according to claim 4, which further comprises determining the maximum speed as the changed speed multiplied by a safety factor.

6. The method according to claim 1, which further comprises: reducing the speed; measuring the vibration state variable during the reducing of the speed; and reducing the speed until the vibration state variable falls below a predetermined limit value due to the reducing of the speed.

7. The method according to claim 1, which further comprises changing the speed to a discrete speed value.

8. The method according to claim 1, which further comprises reducing the speed with a constant deceleration.

9. A method for stabilizing a rail vehicle having a wheel set, which comprises the steps of: changing a speed of the rail vehicle if a critical vibration state of the wheel set occurs; changing the speed of the rail vehicle using a vibration state variable of the wheel set; and only reducing the speed when the critical vibration state of the wheel set occurs above a predetermined minimum speed.

10. The method according to claim 1, which further comprises changing the speed of the rail vehicle using global positioning satellite information for a current position of the rail vehicle.

11. The method according to claim 1, which further comprises changing the speed of the rail vehicle using a measuring signal of an on-board track monitoring device.

12. The method according to claim 1, which further comprises changing a damping of a vibration of the rail vehicle.

13. The method according to claim 1, wherein the changing in the speed is made functionally dependent on the vibration state variable.

14. The method according to claim 1, wherein the stabilizing is an attenuation of a lateral vibration of the wheel set of the rail vehicle.

15. The method according to claim 1, which further comprises incrementally changing the speed to a discrete speed value.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) In the drawings:

(2) FIG. 1 shows a rail vehicle having an arrangement for stabilizing the rail vehicle,

(3) FIG. 2 schematically illustrates a control loop for stabilizing the rail vehicle from FIG. 1,

(4) FIG. 3 schematically illustrates a speed curve of the rail vehicle from FIG. 1 according to the method,

(5) FIG. 4 schematically illustrates another speed curve according to the method, with reductions of the speed to predetermined values,

(6) FIG. 5 schematically illustrates another speed curve with a predetermined speed restriction and

(7) FIG. 6 schematically illustrates an exemplary method sequence.

DESCRIPTION OF THE INVENTION

(8) FIG. 1 shows a rail vehicle 2 having an arrangement 4 for stabilizing the rail vehicle 2. In this exemplary embodiment, the rail vehicle 2 comprises a plurality of cars 6, 8 of which, for representational simplicity, only one car 6 is shown completely and two other cars 8 partially. Obviously it is also conceivable for the rail vehicle to have just a single car which can be a locomotive, a freight car or similar.

(9) The rail vehicle 2 has two pivoted trucks 10 mounted on the underside of the car 6, each having a wheel set 12. Each truck 10 is connected to the car 6 via a damper 14 for damping rotary motion. Each of the wheel sets 12 comprises two wheels 16 interconnected in a torsionally rigid manner via an axle, only one wheel being visible in each case in the side view selected.

(10) The arrangement 4 for stabilizing the rail vehicle 2 comprises a plurality of determining devices 18, a track monitoring device 20 and a control unit 26. A drive unit 22 and a position determining device 24 of the rail vehicle 2 can optionally also be regarded as integral parts of the arrangement 4.

(11) In this exemplary embodiment, the determining devices 18 are disposed on the trucks 10, or more precisely on the wheels 16 of the wheel sets 12, and are each designed to determine a vibration state variable of a respective wheel set 12. In this example, the vibration state variable is a lateral acceleration running essentially at right-angles to the direction of travel 28 of the rail vehicle 2 and in particular horizontally.

(12) The track monitoring device 20 is an instrument designed to detect a geometry defect of a track 30 describing a deviation of the position of the track 30 from a nominal position in a horizontal or vertical direction.

(13) The drive unit 22 is designed to accelerate or decelerate the rail vehicle 2. In contrast to the previous exemplary embodiment, a rail vehicle can also have a plurality of drive units which can be disposed, for example, on the trucks or distributed over individual cars of the rail vehicle.

(14) The position determining device 24 is a receiving unit for receiving signals for satellite-based determination of a current position of the rail vehicle 2.

(15) The control unit 26 is connected to the position determining device 24, the determining devices 18 of the front truck 10 of the car 6 in the direction of travel 28, the drive unit 22 or the track monitoring device 20 by means of the signal connections 32, 34, 36 and 38. The control unit 26 is also connected via the signal connections 40 and 42 to the determining devices 18 of the rear truck 10 in the direction of travel 28 and possibly to other determining devices, particularly those which are present in the other cars 8 of the rail vehicle 2. It is self-evidently also conceivable for each car of the rail vehicle, each truck of a car, each wheel set of a truck or each wheel of a wheel set to have a separate control unit.

(16) The control unit 26 is designed to control the drive unit 22 with a control signal 44 via the signal connection 36 for accelerating or decelerating the rail vehicle 2 using the measuring signals 46, 48 and the position signal 50, i.e. GPS information 50. This setup is also designed for using measuring signals 52 and 54 conveyed via the signal connections 40 and 42 respectively.

(17) FIG. 2 schematically illustrates a control loop 56 for stabilizing the rail vehicle 2 from FIG. 1. The control loop 56 comprises a controller 58, a final control element 60 and a controlled system 62.

(18) The controller 58 is a component part of the control unit 26 described in the previous exemplary embodiment with reference to FIG. 1. The final control element 60 is a component part of the drive unit 22 and the controlled system 62 is a vibration state of a wheel set 12 of the rail vehicle 2. It is also conceivable to describe the controlled system 62 generally as the driving state of the rail vehicle 2, truck or wheel set vibration or similar.

(19) At the output 64 of the control loop 56, a vibration state variable 66 is present as the controlled variable 68 which in this exemplary embodiment is an acceleration of a wheel 16 of the rail vehicle 2 perpendicular to the direction of travel 28. This (lateral) acceleration 66 is advantageous for instrument-based detection of an instability or rather sinusoidal hunting oscillation of the rail vehicle 2.

(20) The controlled variable 68, i.e. acceleration, is determined at the output 64 of the control loop 56 and returned as a measured variable 70 via a feedback path 72 to the input 74 of the control loop 56. This instrument-based determination of the acceleration or rather of the measured variable 70 is performed by the determining device 18 on a wheel set 12 of the rail vehicle 2.

(21) Additionally present at the input 74 of the control loop 56 is a command variable which in this exemplary embodiment is a predetermined limit value 76 of the acceleration of the wheel set 12. After calculation of the difference 78, the difference between the measured variable 70 and the limit value 76 is fed to the controller 58i.e. the control unit 26as the deviation 80. Self-evidently, it is also conceivable for the calculation of the difference 78 to be performed by a function of the control unit 26.

(22) The controller 58 or rather the control unit 26 generates the control signal 44 (see also FIG. 1) using the deviation 80 obtained in this way, i.e. implicitly using the vibration state variable 66, i.e. the controlled variable 68, and uses it to control the final control element 60, i.e. the drive unit 22.

(23) In this exemplary embodiment, the controller 58 also uses GPS information 82 or the measuring signal 50 and the measuring signal 46 of the track monitoring device 20 to generate the control signal 44. The final control element 60 then outputs a manipulated variable 84, i.e. the drive unit 22 decelerates or accelerates the rail vehicle 2 so that the manipulated variable 84 in the form of a changed speed 86 acts on the controlled system 62, i.e. the wheel set, 12.

(24) Because of the changed speed 86, the controlled system 62 changes its state, i.e. a now changed vibration state 66 of the wheel set 12 ensues which is in turn recorded and fed back as a changed (lateral) accelerationwhich is not to be confused with a longitudinal acceleration in the direction of travel 28 of the rail vehicle 2.

(25) In addition, a disturbance variable 88 acts on the controlled system 62 or on the wheel set 12. The disturbance variable 88 is here a force applied to the wheel set 12, or more precisely a braking or acceleration force produced by the drive unit 22 as a result of the control signal 44.

(26) The feedback control process described is run continuously or quasi-continuously for a large number of consecutive points in time until alignment between the measured variable 70 and the limit value 76 is established.

(27) FIG. 3 schematically illustrates a characteristic curve of the speed v (84, 86, cf. FIG. 2) of the rail vehicle 2 from FIG. 1 according to the method. It additionally shows a corresponding time characteristic of a vibration state SZ (66, 68, 70, cf. FIG. 2). Both curves are plotted over time t, both abscissae of the diagram being identical.

(28) Here the speed v is the speed 86 of the rail vehicle 2 and the vibration state SZ is the state of the vibration variable 66 or more specifically the (lateral) acceleration of a wheel set 12 of the rail vehicle 2.

(29) As a fully realistic representation of the vibration state SZ over time t is unnecessary at this juncture for explaining the method and for the sake of better representability, the SZ response is illustrated in a greatly simplified manner. Consequently, the response of the vibration state SZ only reflects the change between two discrete states, namely a critical vibration state KSZ and a non-critical vibration state USZ.

(30) At a time t0a, the rail vehicle 2 (see FIG. 1) is moving at a speed v0a, wherein a non-critical vibration state USZ of the rail vehicle 2 or of the wheel set 12 obtains.

(31) The same features which may, however, exhibit slight differences, e.g. in terms of absolute or numerical value, dimension, position and/or function or the like, are labeled with the same reference numerals and other reference characters. If the reference numeral is mentioned alone without a reference character, this applies to the corresponding components of all the exemplary embodiments.

(32) At a time t1a, a critical vibration state KSZ occurs and the speed v of the rail vehicle 2 is reduced according to the method, e.g. using the control process described in FIG. 2. The speed v is reduced until the vibration state SZ attains a non-critical value USZ, which is the case at time t2a for a speed v1a.

(33) The braking of the rail vehicle 2 between t1a and t2a and the associated frictional forces between wheel 16 and track 30 can produce an effect on the vibration state SZ. It may therefore happen that the rail vehicle 2 is stabilized by a braking operation and the accompanying reduction in the speed v, but after an at least predominant reduction of the braking forcei.e. in the event of at least partial releasing of the brakea critical vibration state KSZ re-occurs.

(34) In order to prevent this, depending on the speed v1a reduced in this way, a maximum speed vm1a, where vm1a<v1a, is determined and set as a speed restriction G1 for the rail vehicle 2 until further notice. The rail vehicle 2 accordingly moves at a speed vm1 until time t3a.

(35) At time t3a, a critical vibration state KSZ re-occurs, the speed v of the rail vehicle 2 is reduced once again until the vibration state SZ attains a non-critical value USZ, which is the case at time t4a for a speed v2a. Again, depending on the speed v2a reduced in this way, a maximum speed vm2a, where vm2a<v2a, is determined and set as a speed restriction G2 for the rail vehicle 2 until further notice. The rail vehicle 2 accordingly moves at a speed vm2 until time t5a.

(36) At time t5a, a critical vibration state KSZ re-occurs, the speed v of the rail vehicle 2 is reduced once again until the vibration state SZ attains a non-critical value USZ, which is the case at time t6 for a speed v3a. Again, depending on the speed v3a reduced in this way, a maximum speed vm3a, where vm3a<v3a, is determined and set as a speed restriction G3 for the rail vehicle 2 until further notice.

(37) The rail vehicle 2 accordingly moves at a speed vm3a from time t7a until further notice. Should a lower speed v be required for track- or schedule-related reasons, the speed can obviously be reduced appropriately or the rail vehicle brought to a stand.

(38) At time t8a, the speed v is increased again, as the rail vehicle 2 has remained within a non-critical vibration state range USZ for a predefined travel span T.

(39) That is to say, at time t8a the speed restriction G3 set at time t6a is removed or canceled and the rail vehicle 2 is accelerated. The rail vehicle 2 is accelerated up to the speed restriction G2 set at time t4a and still in force and reaches it at time t9a.

(40) At time t10a, the speed v is increased again, as the rail vehicle 2 has remained within a non-critical vibration state range USZ for a further predefined travel span T. At this time t10a, the speed restriction G2 set at time t4a is removed and the rail vehicle 2 is accelerated. The rail vehicle 2 is accelerated up to the speed restriction G1 set at time t2a and still in force and reaches it at time t11a.

(41) After another travel span T has been stably negotiated between times t11a and t12a, the last remaining speed restriction G1 is removed and the rail vehicle 2 is accelerated.

(42) In this exemplary embodiment, the predetermined travel span T is a time span between two points in travel time. However, it is also possible for the travel span to be a distance between two points on the route of the rail vehicle 2.

(43) It is also desirable to bring about stabilization of the rail vehicle 2 whilst minimizing inevitably occurring disturbance variables (88, see FIG. 2). Such disturbance variables can be, in particular, forces applied to the wheel set 12 which occur in an impulsive, fluctuating, transient or similar manner.

(44) The speed v is therefore reduced with an essentially constant deceleration b1, b2 or b3 between the times t1a and t2a, t3a and t4a and t5a and t6a respectively. This allows steadying of the braking forces acting on the wheel set 12 during braking, so that the effect of braking force fluctuations as a disturbance variable 88 affecting the stabilization of the rail vehicle 2 or the controlled system 62 is minimized.

(45) It is possible that normal driving states of the rail vehicle 2 at low or moderate speeds v, e.g. when negotiating a switch, briefly produce a critical vibration state KSZ.

(46) In order to prevent a method-related change in the speed as a result of such driving states, the speed is only changed if a critical vibration state KSZ occurs above a predetermined minimum speed v00.

(47) FIG. 4 schematically illustrates another speed characteristic v according to the method and a corresponding characteristic of a vibration state SZ, in each case over time t, wherein the two abscissae of the diagram are again identical. The following descriptions are essentially limited to the differences compared to the preceding exemplary embodiments, to which the reader is referred with regard to features and functions that remain unchanged.

(48) In contrast to the exemplary embodiment illustrated in FIG. 3, here the speed is reduced to predetermined, discrete speed values, thereby enabling a simplified implementation of the method, in particular a simplified translation of parts of the method into software program code, to be achieved. In respect of the simplified illustration of the time characteristic of the vibration state SZ, the explanations relating FIG. 3 apply.

(49) At a time t0b, the rail vehicle 2 (see FIG. 1) is moving at a speed v0b, wherein a non-critical vibration state of the wheel set 12 or a stable running of the rail vehicle 2 obtains.

(50) At a time t1b, a critical vibration state KSZ occurs and the speed v of the rail vehicle 2 is reduced. The speed v is reduced to a predetermined speed value v1b which is used until further notice as a predetermined speed restriction G4 which is reached at time t3b. A non-critical vibration state USZ is achieved as early as time t2b, where t2b<t3b.

(51) At time t4b, the speed v is increased again and the speed restriction G4 is removed, as the rail vehicle 2 has run within a non-critical vibration state range USZ for a predefined travel span T. The speed v is increased to a speed value v2b, where v2b>v0b, wherein an externali.e. non-method-relatedcircumstance is the decisive factor for specifying v2b.

(52) At time t5b, a critical vibration state KSZ re-occurs and the speed v of the rail vehicle 2 is reduced once more. The speed v is again reduced to the predetermined speed value v1b which in turn is used as speed restriction G4 at time t7b. A non-critical vibration state USZ is achieved as early as time t6b, where t6b<t7b.

(53) At time t8b, a critical vibration state KSZ re-occurs and the speed v of the rail vehicle 2 is reduced once again. The speed v is reduced to a predetermined speed value v3b which is used as speed restriction G5 at time t10b. A non-critical vibration state USZ is achieved as early as time t9b, where t9b<t10b.

(54) Then, after passing travel span T, at time t11b the speed is increased to v1b by removing the speed restriction G5.

(55) After passing a further travel span T between times t12b and t13b, the remaining speed restriction G4 is also removed and the rail vehicle 2 is accelerated.

(56) FIG. 5 schematically illustrates another speed characteristic v and a corresponding characteristic of a vibration state SZ.

(57) In contrast to the exemplary embodiments illustrated by means of FIG. 3 and FIG. 4, here the speed is permanently restricted to a predetermined, significantly reduced speed value following repeated occurrences of a critical vibration state KSZ. This makes it possible to prevent speed-induced overstressing of worn components of the rail vehicle 2 and/or safety-critical driving states.

(58) Starting from a speed v0c, if critical vibration states KSZ occur, the speed v of the rail vehicle 2 is successively reduced at times t1c, t3c and t5c to the speed values v1c, v2c and v3c which are attained at times t2c, t4c and t6c respectively.

(59) At time t7c, an instability or a critical vibration state KSZ re-occurs. Because of the now repeated instability of the rail vehicle 2, the speed v is decreased to a predetermined, significantly reduced speed value v4c, wherein the critical vibration state KSZ occurring at time t7c is exited as early as time t8c.

(60) The speed value v4c thus attained at time t9c is set as a speed restriction G6 and the rail vehicle 2 is operated at no more than this speed until further notice.

(61) FIG. 6 schematically illustrates an exemplary method sequence. The rail vehicle 2 is initially moving at a speed v (cf. FIG. 3, v0a) in a stable driving state (cf. FIG. 3, USZ). Accordingly, in this method step 100 no method-related speed restriction is set or active.

(62) If a critical speed state KSZ of the wheel set 12 occurs, the speed v0a is changed 110 using a vibration state variable 66, or more precisely the accelerationi.e. the controlled variable 68. The speed is reduced until the vibration state variable 66 reaches a predetermined limit value (cf. FIG. 2, 76).

(63) In the next step, a maximum speed (e.g. vm1a) different from the changed speed which can be v1a, for example (see FIG. 3), is determined and set 120 as a speed restriction (cf. G1, FIG. 3). The rail vehicle 2 is operated at a speed not exceeding this speed restriction until further notice.

(64) If the rail vehicle 2 has remained within a non-critical vibration state range of the wheel set 12 for a predefined travel span (cf. e.g. FIG. 3, T), the speed restriction previously determined and set 120 is lifted 130 and the speed of the rail vehicle 2 is increased as required.

(65) If an instability re-occurs before the predetermined travel span has been completed, the speed is reduced again 140. Another speed restriction is determined and set 150.

(66) The method steps of changing a speed and setting a speed restriction are repeated if further instabilities occur before predetermined travel spans have been completed. This is repeated until, for example, a maximum number of speed restrictions have been set, the speed has reached or fallen below a predetermined minimum speed or similar. Continuation 160 of the method is indicated by dots in FIG. 3.

(67) If, starting from the setting 150 of the speed restriction, the rail vehicle 2 has remained within a non-critical vibration state range over a predefined travel span, the latest speed restriction determined and set 150 is lifted or canceled 170. However, the speed restriction determined and set 120 remains activated.

(68) If the rail vehicle 2 again completes the predetermined travel span without instabilities occurring, this speed restriction is lifted 130. Thereafter, all the speed restrictions according to the method are inactive and the vehicle again operates in state 100.