EP3870757B1 - Track construction machine and method for tamping sleepers of a track - Google Patents

Description

field of technology

The invention relates to a track construction machine with a tamping unit for tamping under sleepers of a track lying in a ballast bed, comprising a tool carrier mounted in a height-adjustable manner on an aggregate frame, on which tamping tools are arranged so that they can be placed in relation to one another, the tool carrier being coupled to a height adjustment drive controlled by a control device and wherein To regulate a lowering movement of the tool carrier, a control circuit with a controller, an adjusting device for the height adjustment drive and a measuring device for detecting the lowering movement is set up. The invention also relates to a method for operating a corresponding track-laying machine.

State of the art

A track construction machine equipped with a tamping unit is used to create or stabilize a desired track position. The track-laying machine drives along the track and raises the track grate made up of sleepers and rails to a target level using a lifting/leveling unit. The new track position is fixed by tamping the sleepers using the tamping unit. To do this, tamping tools (tamping picks) are set in vibration, lowered into the ballast bed on both sides of a sleeper and placed next to each other in order to compact the ballast under the sleeper. The tamping tools are then lifted out of the ballast bed and moved apart. The tamping unit is positioned over the next threshold and a new tamping cycle begins.

Various solutions are known for lowering and raising the tamping tools. For example describes EP 1 233 108 A1 a lifting and lowering mechanism for a tamping unit, in which a hydraulic cylinder and a lever assembly coupled to a power unit frame. A tamping unit with several tool carriers is out EP 0 698 687 A1 known. Each tool carrier is assigned its own height adjustment drive for separate lowering and lifting.

When specifying the lowering movement, an operator usually has up to three speed levels to choose from in order to take the condition of the ballast bed into account. When new tracks are laid, the lowering usually occurs at a slower speed than with a ballast bed that has hardened due to wear and environmental influences. The aim is to quickly reach a specified immersion depth while keeping the lowering time as constant as possible. A corresponding specification is made manually and is based on the experience of the operator.

AT 519 195 A1 discloses a tamping unit in which a vertical vibration is superimposed on the lowering movement of the tamping tools in order to facilitate penetration of the tamping tools into a hardened ballast bed. However, an additional load on the track construction machine is also accepted because the vertical vibration is also transmitted to a machine frame to which the tamping unit is attached.

From the DE 29 46 737 A1 A generic track construction machine is known in which the lowering movement of the tool carrier is controlled, with a current height position of the tamping tools being recorded.

Summary of the invention

The invention is based on the object of developing a track construction machine of the type mentioned so that the tamping tools of the tamping unit can be lowered into a ballast bed in an optimized manner. In addition, a correspondingly optimized method for operating the track construction machine should be specified.

According to the invention, these tasks are solved by the features of claims 1 and 5. Advantageous developments of the invention result from the dependent claims.

The invention provides that a control circuit with a controller, an adjusting device for the height adjustment drive and a measuring device for detecting the lowering movement is set up to regulate a lowering movement of the tool carrier. This makes it possible to provide an optimal sequence for the lowering movement. This applies to acceleration as well as penetration speed when the tamping picks hit the ballast bed and braking when the immersion depth is reached. With the control, individual phases of the lowering movement can be coordinated with one another, so that overall there is a minimum lowering time while at the same time protecting the track construction machine and the ballast bed.

The measuring device advantageously comprises a position sensor for detecting a height position of the tool carrier. A corresponding controlled variable of the control loop can be easily specified and leads to stable control. Alternatively or additionally, a speed or an acceleration of the tool carrier or the stuffing tools can be recorded.

According to the invention, the controller is preceded by a precontrol or a prefilter, by means of which a reference variable of the control loop can be adjusted by setting up an iterative learning algorithm in a computing unit. The pre-control or pre-filter uses a mathematical model with setting parameters for optimized control of the actuating device in order to follow a predetermined sequence of the lowering movement with minimized deviations.

In an advantageous embodiment of the invention, the height adjustment drive comprises a hydraulic cylinder with a hydraulic valve as an adjusting device. Hydraulic cylinders and hydraulic valves allow optimal control of the lowering and lifting movements with short cycle times and the provision of high forces.

The hydraulic valve is advantageously designed as a pilot-controlled control valve. A highly dynamic and highly precise drive of a pilot control valve enables optimal control of the main stage sufficiently high flow capacity. As an alternative, a servo valve or a proportional valve can be used.

In the method according to the invention for tamping sleepers of a track lying in a ballast bed with a track-laying machine described above, the tamping unit is positioned above a tamping point on the track and the tool carrier is lowered via the height adjustment drive with tamping tools penetrating into the ballast bed, the lowering movement being carried out with a regulated movement size .

In order to minimize control deviations when controlling the lowering movement, a reference variable is modified by means of a pilot control connected upstream of the controller or by means of a pre-filter connected upstream of the controller, with a control difference occurring during a stuffing cycle being fed to a computing unit and starting from the control difference in the computing unit by means of an iterative Learning control algorithm at least one parameter of the pre-control or the pre-filter is adjusted. This automatically responds to changes in the condition of the ballast bed, minimizing control interventions for subsequent tamping cycles.

The lowering movement of the tool carrier is advantageously detected by means of a position sensor. This is either arranged on the tamping unit or at another location on the track construction machine from which contactless detection of the lowering movement is possible.

For stable control, it is advantageous if the control loop is given a reference variable that is dependent on a reduction time. A function can then be generated over time as a predetermined sequence of a lowering movement.

It makes sense if the control circuit is given a lowering path over the lowering time as a reference variable. A desired braking curve and the intended immersion depth can be specified directly in a corresponding time-distance curve.

In an advantageous development, a setpoint curve is specified using a setpoint generator. This is an automated specification

Guide size possible. For example, different setpoint curves are stored in the setpoint generator and a selection is made using an intelligent control assuming one or more track parameters. It can also be useful for an operator to specify parameters or a setpoint curve.

Furthermore, it is advantageous if a feedback variable of the control loop is supplied to the setpoint generator designed as a setpoint generator, with the predetermined lowering movement being adjusted depending on the feedback variable. The feedback variable is the measured controlled variable and allows conclusions to be drawn about the condition of the ballast bed. For example, a heavily compacted gravel bed can mean that a specified immersion depth can no longer be achieved despite control. The setpoint generator then gives the control circuit a lowering movement with a higher immersion speed. In this way, the available adjustment range of the adjusting device is always used optimally.

An improved method also provides that at least one of the variables processed in the control loop is fed to an evaluation device and that a parameter for the ballast bed is derived from the at least one variable by means of the evaluation device. In particular, the manipulated variable, the feedback variable or the control difference allow conclusions to be drawn about the penetration behavior of the ballast bed, which results in a condition parameter of the ballast bed.

Brief description of the drawings

Fig. 1

Stopfaggregat in Seitenansicht

Fig. 2

Regelkreis

Fig. 3

Führungsgrößenverlauf

Fig. 4

Modifizierte Führungsgrößenverläufe

Fig. 5

Regelkreis mit Vorfilter bzw. Vorsteuerung

Fig. 6

Regelkreis mit anpassbarem Vorfilter bzw. anpassbarer Vorsteuerung

Fig. 7

Regelkreis mit Sollwertgenerator zur Generierung eines geänderten Führungsgrößenverlaufes

The invention is explained below in an exemplary manner with reference to the attached figures. It shows in a schematic representation:

Fig. 1

Tamping unit in side view

Fig. 2

control loop

Fig. 3

Command variable progression

Fig. 4

Modified reference variable curves

Fig. 5

Control circuit with pre-filter or pre-control

Fig. 6

Control circuit with adjustable pre-filter or adjustable pre-control

Fig. 7

Control loop with setpoint generator to generate a changed reference variable curve

Description of the embodiments

This in Fig. 1 The tamping unit 1 shown comprises a unit frame 2 which is attached to a machine frame 3 of a track-laying machine which can be moved on rails 4 of a track 5. The tamping unit 1 is used for tamping a ballast bed 6, on which sleepers 7 with the rails 4 of the track 5 attached thereto are stored. A tool carrier 8 is guided in a height-adjustable manner in the unit frame 2, with a lowering movement 9 or lifting movement taking place by means of an assigned height adjustment drive 10.

A vibration drive 11 is arranged on the tool carrier 8, to which two additional drives 12 are connected. Each auxiliary drive 12 is connected to a pivot lever 13. Both pivot levers 13 are mounted on the tool carrier 8 so that they can move relative to each other about a horizontal pivot axis 14 and have tamping tools 15 (tamping picks). The drives 10, 11, 12 are controlled by a control device 16.

During a tamping process, the free ends of the tamping tools 15 (pick plates) penetrate into the ballast bed 6 to below the lower edge of the sleeper and compact the ballast below the relevant sleeper 7. Fig. 1 shows the tamping unit 1 during such a phase of the tamping process. The tamping tools 15 are then reset and lifted out of the ballast bed 6. The tamping unit 1 is moved to the next threshold 7 and a new tamping cycle begins with a lowering movement 9.

With an optimized lowering movement 9, the desired immersion depth 17 of the tamping tools 15 is reached as quickly as possible, although the forces that occur do not cause any disruptive loads on the track construction machine. In addition, the immersion depth 17 should be reached exactly and not exceeded so as not to damage either the sleepers 7 or a subgrade located under the ballast bed 6.

This optimized lowering movement 9 is achieved according to the invention by a control circuit set up in the track construction machine with a controller 18, an adjusting device 19 for the height adjustment drive 10 and a measuring device 20 for detecting the lowering movement 9 ( Fig. 2 ). To the To specify the sequence of the lowering movement 9, a setpoint generator 21, for example, supplies an in Fig. 3 The setpoint curve shown for a controlled variable x. Several setpoint curves can also be stored in the setpoint generator 21. A selection is made by means of an intelligent control assuming at least one track parameter or by an operator. The output of the setpoint generator 21 serves as a reference variable w of the control loop. For example, a lowering path s of the tool carrier 8 is provided as the controlled variable x. The speed and/or acceleration of the tool carrier 8 can also be used as a controlled variable x.

The controller 18 includes a control element 22 and supplies a controller output variable y, which is fed to an actuator 23 to form a manipulated variable u. For example, a pilot-controlled control valve for a hydraulic cylinder of the height adjustment drive 10 serves as the actuating device 19. The actuator 23 is then an actuator of this pilot-controlled control valve and controls an actuating path of the control valve as a manipulated variable u. An existing control system 24 includes, as an actuator 25, the valve body of the control valve and all other components influencing the lowering movement 9. These include the hydraulic cylinder of the height adjustment drive 10 and all lowered components of the tamping unit 1 as well as components of the processed area of the track 5. In particular, the masses of the lowered components and a penetration resistance of the ballast bed 6 come into play here.

The controller output variable y output by the control element 22 is based on a control difference e, which results from the reference variable w minus a feedback variable r. The feedback variable r is the controlled variable x recorded with the measuring device 20. Specifically, the controller 18 determines a numerical control value (numerical value of the controller output variable y) from a difference between a setpoint value (numerical value of the reference variable w) and an actual value (numerical value of the measured controlled variable x), which is specified to the controller 23.

Disturbances z act on the controlled system 24. This is, in particular, a change in the penetration resistance as a result of a changing condition of the ballast bed 6. The disturbance of the controlled variable x caused by a changed penetration resistance results in a control difference e. The manipulated variable u then supplied by the controller 18 and actuator 23 causes a changed control of the height adjustment drive 10, which counteracts the malfunction.

For example, if the tamping tools 15 penetrate too quickly into the ballast bed 6, a force acting from the height adjustment drive 10 on the tool carrier 8 is reduced. If penetration is too slow, the force is increased. In this way, the lowering movement 9 is always readjusted to the specified reference variable w in the event of target deviations. The tamping tools 15 penetrate the ballast bed 6 at optimal speed and reach exactly the desired penetration depth 17. In addition, the penetration time in the individual tamping cycles is kept constant.

In order to minimize the intervention of the control system, it makes sense to provide a pre-control or a pre-filter 26 for the reference variable w ( Fig. 5 ). The aim of this measure is a modified reference variable w', which anticipates the conditions of the controlled system 24. For example, for the lowering path s specified as the controlled variable x, a changed curve course is specified over time t, as in Fig. 4 shown. The system consisting of tamping unit 1 and processed track 5 then follows this modified reference variable specification with almost no control intervention.

The course drawn with a solid line is intended for a soft gravel bed 6 with lightly compacted gravel. The further courses correspond to specifications for an increasingly compacted gravel bed 6, up to the dotted course for a very heavily compacted gravel bed 6. In order to achieve the desired penetration depth 17 in the allotted time, a higher speed is required in the starting phase of the penetration.

A further improvement provides for a parameter adjustment of the pre-control or pre-filter 26, as in Fig. 6 shown. For this purpose, according to the invention, a computing unit 27 is provided, to which a control difference e _k occurring during a stuffing cycle k is supplied. This control difference e _k results consists of the unmodified reference variable w _k minus the feedback variable r _k .

A so-called iterative learning control algorithm 28 is set up in the computing unit 27. This is used to derive an optimized modified reference variable w' _k+1 for the next stuffing cycle k+1 using the control difference e _k and the modified reference variable w' _k of the stuffing cycle k under consideration. Several past stuffing cycles with the resulting control differences e can also be used for this calculation.

So that the optimized modified reference variable w' _k+1 is used, the setting parameters of the precontrol or prefilter 26 are changed in a next step. For this purpose, a corresponding setting algorithm 29 is set up in the computing unit 27. The changed pre-control or the changed pre-filter 26 causes a reduction in the control activity, whereby the control becomes more stable overall. Initial conditions for the iterative learning control algorithm 28 are either specified by an operator or an assumption is made using an intelligent control. The iterative adjustment of the parameters then starts from this specification. In a simple variant, the same initial conditions are always assumed.

Another improvement is with reference Fig. 7 explained. Here the setpoint generator 21 is designed as a setpoint generator. Similar to a trajectory generator, this setpoint generator generates a sequence of the lowering movement 9, for example as a course of the lowering path s over time t. In this way, the setpoint generator supplies the controller 18 or the precontrol or the prefilter 26 with the reference variable w. In addition, the setpoint generator is supplied with the feedback variable r in order to detect deviations from the reference variable w. Here too, initial conditions are specified either by an operator or by an intelligent controller based on assumed track parameters.

Increasing deviations indicate that the control is reaching its limits because the generated reference variable w is no longer achievable is. As soon as the deviations reach a level that is no longer negligible, the setpoint generator generates a new specification for the lowering movement 9. For example, a limit value for permissible deviations is specified, so that when the limit value is reached, the setpoint generator generates a new course of the lowering path s over time t. In this way, a changed condition of the ballast bed 6 is automatically responded to without affecting the stability and accuracy of the control.

The setpoint generator can also be used at the beginning of a work assignment in order to specify a starting sequence for the lowering movement 9. It is advantageous if several test tampings are carried out in order to adapt the specifications for the control to the prevailing conditions.

The electronic components of the control, in particular the setpoint generator 21, the controller 18 and possibly the computing unit 27, are set up in a separate electronic circuit or integrated in the control device 16. The measuring device 20 is arranged, for example, directly on the height adjustment drive 10, whereby a hydraulic cylinder with integrated path measurement makes sense.

In addition, in an expanded embodiment, an evaluation device 30 is provided, to which at least one variable u, e, r of the control loop is supplied in order to derive a parameter for the ballast bed 6. Such a parameter indicates, for example, whether it is new gravel or heavily compacted and contaminated gravel.

Claims (11)

1. A track maintenance machine having a tamping unit (1) for tamping sleepers (7) of a track (5) lying in a ballast bed (6), including a tool carrier (8) which is mounted for vertical adjustment on an assembly frame (2) and on which tamping tools (15) are arranged so as to be squeezable towards one another, wherein the tool carrier (8) is coupled to a vertical adjustment drive (10) actuated by means of a control device (16) and wherein a control circuit is set up for controlling a lowering motion (9) of the tool carrier (8), the control circuit including a controller (18), a setting device (19) for the vertical adjustment drive (10) and a measuring device (20) for recording the lowering motion (9) characterized in that the control circuit is provided with a computing unit (27) and that a pre-control or a pre-filter (26) is installed upstream of the controller (18), by means of which a command variable (w) can be adjusted wherein in the computer unit (27), a so-called iterative learning control algorithm (28) is set up.
2. A track maintenance machine according to claim 1, characterized in that the measuring device (20) includes a position sensor for recording a vertical position of the tool carrier (8).
3. A track maintenance machine according to one of claims 1 to 2, characterized in that the vertical adjustment drive (10) comprises a hydraulic cylinder having a hydraulic valve as a setting device (19).
4. A track maintenance machine according to claim 3, characterized in that the hydraulic valve is designed as a pre-controlled regulating valve.
5. A method for operation of a track maintenance machine according to one of claims 1 to 4, wherein the tamping unit (1) is positioned above a tamping location of the track (5), and that the tool carrier (8) is lowered via the vertical adjustment drive (10) with the tamping tools (15) penetrating into the ballast bed (6), and the lowering motion (9) is carried out with a controlled motion variable (x, s), characterized in that a command variable (w) is modified by means of a pre-control installed upstream of the controller (18) or by means of a pre-filter (26) installed upstream of the controller (18) in that way that a control difference (e_k) occurring during a tamping cycle (k) is fed to a computing unit (27), and that - based on the control difference (e_k) - at least one parameter (p) of the pre-control or of the pre-filter (26) is adjusted in the computing unit (27) by means of an iterative learning control algorithm (28).
6. A method according to claim 5, characterized in that the lowering motion (9) of the tool carrier (8) is recorded by means of a position sensor.
7. A method according to claim 5 or 6, characterized in that a command variable (w) depending on a lowering time (t) is prescribed to the control circuit.
8. A method according to claim 7, characterized in that a lowering path (s) over the lowering time (t) is prescribed as a command variable (w) to the control circuit.
9. A method according to one of claims 5 to 8, characterized in that a target value progression is prescribed by means of a target value encoder (21).
10. A method according to claim 9, characterized in that a return variable (r) of the control circuit is fed to the target value encoder (21) designed as a set-point generator, and that the prescribed lowering motion (9) is adjusted in dependence on the return variable (r).
11. A method according to one of claims 5 to 10, characterized in that at least one of the variables processed in the control circuit is fed to an evaluation device (30), and that a parameter for the ballast bed (6) is derived from the at least one variable by means of the evaluation device (30).

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