EP2366831B1 - Method for controlling the process of applying a layer of road paving material and paver - Google Patents

Description

The invention relates to a method according to the preamble of claim 1 and a road finisher according to the preamble of patent claim 7.

Out DE 198 36 269 A a method is known in which the tamper frequency is regulated in dependence on the scanned angle of the screed according to a predetermined law. Since only the angle of attack is taken into account as the influencing variable alone, the operator must set further influencing variables according to feeling, ie the operator can not directly control the installation process, but has to select certain machine parameters himself, whereby he is supported by the control of the tamper frequency depending on the angle of attack , It is up to the operator to select the machine parameters to be entered in such a way that he ultimately achieves the desired result.

Out DE 40 40 029 A a method is known in which the tamper frequency is varied in dependence on the installation speed according to a predetermined law. Further machine parameters must be selected and entered by the operator so that no direct control of the installation process is possible.

Out EP 1 179 636 A is a paver known, the screed has in Vorverdichtungssystem a tamper whose tamper speed is remotely adjustable in a closed loop to vary the frequency of Tamperhübe. However, the effect of changing the tamper speed to the precompression result is small.

On off DE 200 10 498 U1 Known road paver has in the screed in Vorverdichtungssystem on an eccentric drive with a fixed amplitude, ie fixed tamper, operable tamper and optionally a vibration device for the screed plate on. At the rear of the Glättbleches a pressure bar is arranged, which rests constantly on the surface of the precompressed coating and is hydraulically acted upon by Schwellkraftimpulsen to produce a high compression. The pressure bar is not part of the precompression system.

With one out EP 1 258 564 A known automatic tamper control system can be the tamper frequency or the number of strokes of the tamper strip per unit of the traveled route adjust or adjust automatically depending on changes in the installation speed. The tamper stroke is not changed. The tamper frequency has a relatively small influence on the precompression result.

From the European patent application with seniority senior, Anmeldeaktenzeichen 09 014 516.0 a proposal is known to vary at least the tamper automatically under consideration of various installation parameters. Again, no direct process control is possible because the angle of attack of the screed or occurring during installation change of the angle of attack is not taken into account. The angle of incidence of the screed would be a very useful indicator of the operating state or operating point of the precompression system, because too shallow or too steep an angle inevitably results in problems regarding the achievable compression, flatness and structure of the lining.

Furthermore, in practice leveling systems or even automatic leveling systems for road pavers are known, which typically contain closed control loops and control the leveling cylinders of the paver. At least one sensor samples a reference and provides a reading that is compared to a setpoint in the system. The setpoint is input by an operator. The system then generates a control signal for the leveling cylinders. In this way, the lining thickness is controlled, taking into account other significant machine parameters for the lining thickness, such as the tamper stroke, the tamper frequency and the installation speed. These machine parameters must be optimally selected and implemented by the operator. The machine parameters are not process objectives, which means that the operator can not set what he wants to achieve, namely a certain amount of lining. The operator controls the machine, so to speak, in order to finally achieve the desired result. Direct process control is not possible with this method.

The invention has for its object to provide a method of the type mentioned above and a paver for performing the method, which make it possible to control the installation process directly, without burdening operators with impractical high responsibility of selecting right machine parameters.

The stated object is achieved with the features of claim 1 and with the paver with the features of claim 7.

In the process, the installation process is controlled directly and largely automatically, because the control system knows and takes into account all relevant process target values, and above all takes into account the angle of attack of the screed as an additional control variable, to regulate the lining thickness to the target value and also to optimize the operating point of the precompression system so that the target lining thickness is achieved with optimum pre-compaction, optimum flatness and optimum structure of the lining with minimal wear of the working components and with minimal energy consumption. The angle of attack as here continuously recorded and taken into account control variable is processable as a relevant indicator of the operating state of the precompression system by the control system to avoid in the process control that too low or too steep angle of incidence arises, the achieved compaction, flatness and structure negative would affect. The control system processes the information about the actual installation speed and the actual angle of attack of the screed so that the manipulated variables are generated and converted with respect to the setpoint of the lining thickness, wherein the actual angle of attack is kept largely at the preselected desired angle of attack. An actuator for the tamper stroke generated via an eccentric drive is a remote-controlled transmission for adjusting the eccentricity according to the method during the installation process, which is causally responsible for the size of the tamper stroke. The gear can be adjusted mechanically, hydraulically or electrically.

The paver can be performed with greater comfort and without basic knowledge of the context of different installation parameters by a relatively untrained operator with high comfort for the installation process, which is controlled by the direct process control, the layer thickness to setpoint while the operating point of the precompression system is optimized. An actuator for the tamper stroke generated via an eccentric drive is a remote-controlled transmission for adjusting the eccentricity according to the method during the installation process, which is causally responsible for the size of the tamper stroke. The gear can be adjusted mechanically, hydraulically or electrically. With the paver with regulated lining thickness an optimal pre-compaction with optimal flatness and optimum structure of the coating can be produced, with minimal wear on the working components can be achieved and worked with minimal energy consumption.

In a suitable variant of the method control signals are generated at least for the tamper or tamper frequency, or even for the tamper and tamper frequency by the control system in the process control, which are then implemented by the corresponding actuators so that even taking into account the angle of attack as a control variable of the tamper The main contribution is to achieve the right thickness evenly with optimum precompression, flatness and structure of the lining.

In a further variant of the method additionally actuating signals for actuators of the leveling cylinder and / or the lifting cylinder are generated and implemented to assist the Vorverdichtungssystem by adjusting the height of the articulation points of the traction arms and / or by an over the lifting cylinder relief of the screed for example, while maintaining the target value of the pitch ,

In an expedient method variant, the detected actual installation speed is transmitted as manipulated variable information for processing to the control system. A change in the installation speed causes an automatic change of the control signals for the actuators in order to keep both substantially constant, namely the lining thickness and the angle of attack.

In an alternative method variant, the installation speed is selected or preselected by an operator and the actual installation speed is transmitted as disturbance information for processing to the control system. Although the installation speed is made available to the control system for processing in this case, it can be freely selected by an operator. This is important because the installation speed should be chosen in practice so that the desired performance (mass flow rate of paving material, area performance) is tuned to the particular circumstances or specific requirements. Therefore, it is expedient, in spite of the automatic control or control of the installation process, to offer the operator an influence, at least with regard to the installation speed.

In a further variant of the method, the control system generates an installation speed recommendation in the form of a speed value or speed range for the operator during direct process control, which the operator can implement or implement with regard to optimum performance during the installation process.

It is expedient for at least some or all of the acquired information for direct process control in the control system to be processed as control variables in order to generate at least the control signals for the tamper stroke or the tamper frequency or the tamper stroke and the tamper frequency. Flanking can also be generated and implemented control signals for the leveling cylinder or the lifting cylinder to make the process control essentially only by the control system and to relieve the operator.

In an expedient embodiment of the paver, actuators are connected to the control system at least for setting the tamper stroke or the tamper stroke and the tamper frequency based on control signals generated by the control system. By implementing this Adjusting signals is optimized, taking into account the speed of installation and above all the angle of attack, the precompression performance of the precompression system in order to achieve the desired lining thickness and to vary the angle of attack is not appreciable. Namely, a certain precompression performance, depending on the tamper stroke and the tamper frequency, would cause the screed to increase and the angle of incidence to increase inconveniently, while increasing the paving speed would lead to the opposite result, namely, lowering of the screed and an increase in the angle of attack would lead, each with unwanted side effects.

To exclude or minimize such side effects in the process control, it may be useful in another embodiment, in addition to connect control elements for adjusting the leveling cylinder and / or the lifting cylinder based on the control system generated control signals to avoid unwanted changes in the angle of attack or with the control system counteract this immediately.

In an expedient embodiment of the road paver, the control system either comprises at least one, preferably a plurality of, in-line, gain controllers, for example three size controllers, one of which is e.g. one tames the tamper frequency in consideration of the installation speed, another regulates the tamper stroke taking into account the angle of attack, and another actuates the leveling cylinder taking into account the lining thickness, or at least one multi-variable controller which, for example, processes a plurality of control variables and generates a plurality of actuating signals. For example, the multivariable controller processes the control variables paving speed and angle of attack and generates the control signals for changing the tamper frequency and the tamper stroke. On the other hand, the in-feed controller processes the information on the pad thickness and, if necessary, generates actuating signals for the leveling cylinders and / or the lifting cylinders.

In an expedient embodiment, the control system is equipped with a display in which, inter alia, a built-speed recommendation for an operator can be displayed, for example if the control system learns self-learning that the installation speed is too high or too low or due to a change in a control variable of a change requirement.

In the control system classic PID controller, adaptive controller, but also fuzzy logic controller, neural network controller, or other controllers can be used.

Furthermore, it may be expedient to provide in the control system at least one predetermined characteristic or a characteristic field and / or a characteristic curve or characteristic diagram control for manipulated variables to be correlated with one another.

An actuator for the tamper frequency generated by a hydraulic drive may be a solenoid-operated valve, preferably even a proportional flow control valve, to adjust the tamper frequency above the speed generated by the hydraulic drive.

An actuator for the angle of attack of the screed may be at least one solenoid-operated valve for the leveling cylinder, wherein the current actual position of the leveling cylinder can be fed back to the control system. An actuator, preferably for setting a particular plank relief, may be a solenoid operated valve for the hydraulic lift cylinders.

The direct process control can also take into account to vary at least the Tamperhub or the Tamperhub and the tamper frequency over the pave width of the screed at a transverse to the working direction pad thickness to produce the same compaction also transverse to the working direction.

Fig. 1

eine schematische Seitenansicht eines Straßenfertigers beim Ausführen eines Einbauprozesses,

Fig. 2

ein Detail einer Einbaubohle des Straßenfertigers von Fig. 1,

Fig. 3

eine Schemadarstellung eines Regelsystems des Straßenfertigers von Fig. 1,

Fig. 4

eine andere Ausführungsform des Regelsystems in schematischer Darstellung, und

Fig. 5

eine weitere Ausführungsform des Regelsystems in schematischer Darstellung.

With reference to the drawings, embodiments of the subject invention will be explained. Show it:

Fig. 1

a schematic side view of a paver when performing a mounting process,

Fig. 2

a detail of a screed of road paver from Fig. 1 .

Fig. 3

a schematic representation of a control system of the paver of Fig. 1 .

Fig. 4

another embodiment of the control system in a schematic representation, and

Fig. 5

a further embodiment of the control system in a schematic representation.

Fig. 1 shows a self-propelled road paver 1 when performing a mounting process, ie, when installing a covering 6 bituminous or concrete-5 on a planum 7 with a covering thickness S and a mounting speed V relative to the planum 7, wherein the covering 6, at least by a precompression 13th a screed 3 pre-compressed and just installed.

The core of the paver 1 is a computerized, either fully automatic or user-assisted control system 25, for example, in a control panel P on a cab and / or in an outside steering position P 'on the screed 3. The control system 25 is used by an operator so that the operator Directly control installation process, and essentially does not need to select any installation parameters themselves and / or need to change during installation.

On a chassis 2 of the road paver 1, a bunker 4 is arranged frontally, from which a non-highlighted longitudinal conveyor system 5 deposits behind the chassis 2 on the subgrade 7, where it is distributed by a transverse distribution before the screed 3 from the pavement 6 is installed. The screed 3 is mounted on Zugholmen 8, which are hinged to articulation points 9 on the chassis 2 so that the screed 3 is floating on the paving material 5 is dragged. The articulation points 9 are height-adjustable with leveling cylinders, for example via actuators 10 '(hydraulic valves or the like) and influence an angle of attack α of the screed 3. The angle of attack α should be positive but with an optimal size, i. not too shallow and not too steep, and is controlled by the control system 25 at an optimum size. In addition, 2 lifting cylinders 28 are hinged to the chassis, which act on the Zugholmen 8 and serve, for example, for transporting the screed 3 excavated position, or make a plank relief during installation or optionally to increase the contact pressure of the screed 3.

The screed 3 comprises, for example, a base screed 11 and extending screeds 12, each with a precompression system 13, for example at least one tamper 14, and optionally a vibration device, not shown, for a bottom screed 18. As an option, the screed 3 can also be used with a high compression device, not shown be equipped. The tamper 14 is (see Fig. 2 ) For example, by means of an eccentric drive with selectable stroke H and selectable frequency F operable.

The outside steering position P 'on the screed 3 may have a similar equipment as the control panel P. In the control panel P, a speed selector 26 is provided for setting the installation speed V. The speed selector 26 can be adjusted by an actuator, not shown, if necessary, also from the control system 25 to change the installation speed V. The actual installation speed V is detected by at least one symbolically indicated sensor 31 and transmitted to the control system 25. The sensor 31 may be placed in the paver, for example in the control panel P or in a traction drive or scan a reference on the planum 7. In the control panel P or in the control system 25, an input section 27 may be provided for inputting and / or displaying parameters. The lifting cylinders 28 is at least one actuator 28 ', for example, a solenoid-operated hydraulic valve assigned. Furthermore, at least one sensor 30 can be provided as equipment of the road paver 1, which picks up the temperature, density or consistency of the built-in material, for example immediately before the screed 3, and optionally transmitted as information to the control system 25. This installation parameter could alternatively be entered by the operator. For example, at the screed 3, at least one sensor 29 is provided, which detects the angle of attack α of the screed 3, for example relative to the planum 7. This sensor 29 could tapping the angle α also at the Zugholmen. It could be provided over the mounting width several sensors 29. Furthermore, a sensor 37 may be provided for picking up the lining thickness S, which scans, for example, the plane 7 or a reference line, not shown.

Actuators for setting the Tamperhubes H and the tamper frequency F are also provided in the paver 1 or the screed 3 to implement generated by the control system 25 control signals.

For example, shows Fig. 2 a partially exposed portion of the screed 3 with the precompression system 13 and the tamper 14. The tamper 14 may be shielded at the front of the screed 3 by a cover 19 and between the cover 19 and the front edge of the Glättbleches 18 substantially vertically movably guided. On a lower side of the screed plate 18 supporting frame 17, a bearing block 16 is mounted, the relative altitude is adjustable for example by means of an adjusting screw 20, such that the tamper 14 has a certain relative position to the screed plate 18 at the bottom dead center of each stroke. In the bearing block 16 (over the length of the frame 17 a plurality of bearing blocks 16 may be mounted) is an eccentric shaft 15 rotatably mounted, each having an eccentric portion 22 of a certain eccentricity. The eccentric portion 22 engages in a connecting rod 21, which connects the eccentric shaft 15 with the tamper 14. On the eccentric portion 22 is an eccentric bushing 23 via a the actuator for the tamper stroke H forming gear 24 rotatably coupled to the eccentric portion 22. The gear 24 is supported on the frame 17. The eccentric bush 23 is rotatably mounted in the connecting rod 21. By means of the gear 24, the eccentric bushing 23 can be relative to the eccentric section Twist 22 and couple in the set rotational position with the eccentric shaft 15. The relative rotation of the eccentric bushing 23 relative to the eccentric section 22 effects an adjustment of the stroke, which the connecting rod transmits to the tamper 14. The tamper stroke H is set automatically via the control system 25.

The eccentric shaft 15 is rotationally driven, for example, by a hydraulic motor 32. The speed determines the tamper frequency F. As the actuator 33 for the hydraulic motor 32 may serve a solenoid-operated valve, such as a proportional flow control valve, which is acted upon by the control system 25 with control signals. The representation of the transmission in Fig. 2 is only to be understood schematically, since the transmission 24 of course due to the rotation of the eccentric shaft 15 indirectly as adjusting on the eccentric shaft 15 has an effect on the eccentric bushing 23. For the gear 24 as an actuator for setting the Tamperhubes H different versions are conceivable, of which Fig. 2 only one non-limiting embodiment shows.

The control system 25 is designed to directly control the installation process and to require an operator to input only process targets such as a certain lining thickness S, for example at the input section 27, and then control the installation process without further operator intervention. The paver 1 can drive at a predetermined or programmed installation speed V, where appropriate, an operator can select the installation speed V, and / and the control system 25, for example, in a non-highlighted display the operator is offered a built-speed recommendation that the control system 25, for example in In terms of the process objective or optimal performance (mass flow, area performance), and which can then be implemented by the operator. Since external influences can cause changes in the installation speed V with respect to the specification, eg gradients, gradients, driving resistance, and the like, the sensor 29, however, picks up the actual installation speed and transmits it to the control system 25 so that the process control is not interrupted by a the default deviating installation speed change is falsified. The same applies to the actual angle of attack α, which is initially determined by the height adjustment of the articulation points 9 and the desired covering thickness S, but may vary during the installation process due to external influences and therefore detected, for example by the at least one sensor 37 within the working width and is transmitted to the control system 25.

Alternatively, the installation speed V could be taken into account as a disturbance variable, ie the installation speed V is made available to the control system 25 for processing, for example by the information provided by the at least one sensor 29 and / or by the speed selector 26, but by an operator can be chosen. This is significant because the paving speed is used to set the optimum performance of the paver during the paving process (mass flow, area performance).

During the installation process, the control system 25 regulates the lining thickness S to a predetermined desired value. Furthermore, the control system 25 optimizes the operating point of the precompression system 13 with the tamper 14 such that the desired value of the layer thickness S with optimum pre-compaction, optimal flatness and optimum structure of the coating 6 with minimal wear, for example in the precompression system 13 and minimal energy consumption is achieved. This positive effect also leads the control system 25 above all by the fact that the angle of attack α of the screed is determined and processed as an additional control variable. For the angle of attack α is an excellent indicator for assessing the operating state of the precompression system 13. For example, for example, too shallow as well as too steep an angle α would cause problems in the compression, the flatness and in the structure.

The Fig. 3 to 5 show a selection of embodiments of the control system 25. This selection is not intended to be limiting.

In Fig. 3 For example, the control system 25 has a controller 35, which is designed as a multi-variable controller 38, and to which a comparator section 34 is assigned. The comparator section 34 receives, for example, specifications iα and i _s for the angle of attack α and the lining thickness S, for example as nominal values. Dotted is indicated that the installation speed V, such as entered by an operator, can be considered here. This dashed line indicated input of the installation speed V, an operator on the basis of a generated by the control system 25 and, for example, in a display, not shown installation speed recommendation E _v choose if the control system 25 should determine that the originally specified installation speed V is not appropriate. The comparator section 34 also transmits the values detected by the sensors 29, 37 as information about the lining thickness S and the angle of attack α. If differences occur between the specifications and the actual values, the comparator section 34 feeds the controller 35, which also contains the actual installation speed detected by the at least one sensor 31 is supplied as information i _v . From the information supplied, the controller generates 35 control signals H for the tamper stroke and / or F for the tamper frequency, and, optionally, at least one actuating signal either for the leveling cylinders 10 (the actuator 10 ') and / or the lifting cylinders 28 (actuator 28'). ). By implementing these control signals, the installation process 36 is controlled so that the desired covering thickness S is achieved and also the angle of attack α is maintained, in which case feedbacks to the comparator section 34 are indicated.

In the embodiment in FIG Fig. 4 the control system 25 is formed here with three parallel size controllers 39, 40, 41. The inputs controller 39 receives, for example, from the sensor 31, the installation speed information (possibly also from the speed selector 26 or superimposed with its setting) and generates the control signal for the actuator 33 of the tamper frequency F. The inputs controller 40 receives the information on the actual angle of attack α and generates the actuating signal for the actuator (gear 24) for setting the Tamperhubes H. The inputs controller 41 receives the information on the lining thickness S (the setpoint or a determined from the setpoint and the actual control variable) and generates actuating signals for the actuator 10th 'and / or 28' for the leveling cylinder 10 and the lifting cylinder 28th

In the embodiment in FIG Fig. 5 The control system 25 includes a multi-variable controller 38 and at least one inputs regulator 41. The multi-variable controller 38 receives the installation speed information from the at least one sensor 31 and also the information on the angle of attack α and generates control signals for the tamper and tamper H. The inputs controller 41 receives the information on the coating thickness S and generates, if appropriate, control signals, for example, for the actuators 10 ', and / or 28'.

The controllers in embodiments 3 to 5 may be classical PID controllers, or adaptive controllers, or fuzzy logic controllers or neural network controllers or other computerized controllers. Further, the controller or the control system may include characteristics or maps or displayed as a characteristic / map control. The characteristic curves relate, for example, to manipulated variables to be correlated with each other, e.g. F or H; F and H; F or H and α, F or H and 10 ', 28', or the like.

Claims (16)

1. Method for controlling the process of applying a layer (6) of bituminous or concrete road paving material (5) in a selectable paving thickness (S) on a formation level (7) with a paver (1) self-propelled at a laying rate (V) and towing a floating screed (3) at anchoring point (9) by towing spars (8), wherein the screed (3) comprises a pre-compaction system (13) with at least one tamper (14), which can be operated by an excenter drive with selectable stroke (H) and selectable frequency (F), the anchoring points (9) of the towing spars (8) being adjustable in height by levelling cylinders (10) and the towing spars (8) being pivotable by lifting cylinders (28) about the anchoring points (9), characterised in that the applying process (36) is automatically controlled in that a target value (i_s) for the paving thickness (9) is input into an automatic closed-loop control system (25), an actual angle (α) of attack of the screed (3), the actual paving thickness (S) and the laying rate (V) are acquired and communicated as information to the control system (25), that the control system (25), at least from the communicated information, generates actuating signals (H, F) for actuating members (10', 28', 24, 33) and communicates the actuating signals to actuating members which automatically implement the actuating signals by controlling the actual paving thickness (S) to the target value (i_s) of the paving thickness (S) and optimizes an operating point of the pre-compaction system (13), wherein actuating signals (H) are generated at least for the tamper stroke and are implemented by an actuating member (24) in the form of a remotely operable gear train for adjusting during the applying process the eccentricity for the tamper stroke (H) as produced by an excenter drive.
2. Method according to Claim 1, characterised in that additionally actuating signals for actuating members (10') of the levelling cylinders (10) and / or for actuating members (28') of the lifting cylinders (28) are generated.
3. Method according to Claim 1, characterised in that the acquired actual laying rate (V) is communicated for processing to the closed-loop control system (25) as an actuating variable information.
4. Method according to Claim 1, characterised in that the laying rate (V) is selected by an operator and either the selected laying rate or the acquired actual laying rate is communicated for processing to the closed-loop control system (25) as a disturbance variable information.
5. Method according to at least one of the preceding claims, characterised in that the closed-loop control system (25) generates a laying rate recommendation (E_v) for an operator in the form of a speed value or a speed range, and that the operator implements the laying rate recommendation.
6. Method according to at least one of the preceding claims, characterised in that at least some of the acquired information are processed in the closed-loop control system (25) as regulation input variables.
7. Paver (1) comprising a screed (3) attached to towing spars (8) for applying a layer (6) of bituminous or concrete road paving material (5) in a paving thickness (S) on a formation level (7), wherein the screed (3) has a pre-compaction system (13) with at least one tamper (14) operable by an excenter drive with selectable stroke (H) and selectable frequency (F), anchoring points (9) of the towing spars (8) being adjustable in height by levelling cylinders (10) and the towing spars (8) being pivotable by lifting cylinders (28) about the anchoring points (9), characterised in that for controlling the laying process (36), the paver (1) has a computerised, either fully automatic or operator aided closed-loop control system (25) for controlling the paving thickness (S) to a predetermined target value (i_s) and for optimising an operating point of the pre-compaction system (13), that sensors (29, 37, 31) at least for the acquisition of the angle (α) of attack of the screed (3), of the paving thickness (S) and of the laying rate (V) are connected to the control system (25), and that an actuating member (24) at least for adjusting the tamper stroke (H) based on actuating signals generated by the control system (25) during the applying process is connected to the control system (25), and that the actuating member (24) is a remotely operable gear train for adjusting the eccentricity of the tamper stroke (H) of the tamper (14), which tamper stroke (H) is generated by the excenter drive.
8. Paver according to Claim 7, characterised in that an actuating member (33) for adjusting the tamper frequency (F) based on actuating signals generated by the control system (25) during the applying process is also connected to the closed-loop control system (25).
9. Paver according to Claim 7, characterised in that additionally actuating members (10', 28') for adjusting the levelling cylinders (10) and / or the lifting cylinders (28) based on actuating signals generated by the control system (25) are connected to the closed-loop control system (25).
10. Paver according to at least one of Claims 7 to 9, characterised in that the closed-loop control system (25) has at least one, preferably three parallel connected single-variable regulators (39, 40, 41) and / or at least one multi-variable regulator (38).
11. Paver according to at least one of Claims 7 to 10, characterised in that the closed-loop control system (25) is linked to a display at least for displaying a laying rate recommendation for an operator.
12. Paver according to at least one of Claims 7 to 11, characterised in that the respective single-variable regulators (39, 40, 41) or the multi-variable regulator (38) is a PID-regulator or an adaptive regulator or a fuzzy-logic regulator or a neural-network regulator.
13. Paver according to at least one of Claims 7 to 12, characterised in that in the closed-loop control system (25) is provided at least one predetermined characteristic curve or a characteristics map and / or a control based on a characteristic curve or on a characteristics map of mutually correlated actuating variables.
14. Paver according to at least one of Claims 7 to 13, characterised in that an actuating member for the tamper frequency (F) as generated by a hydraulic drive is a solenoid-operated valve (33), preferably a proportional flow rate control valve.
15. Paver according to at least one of Claims 7 to 14, characterised in that an actuating member for the angle (α) of attack of the screed (3) is a solenoid-operated valve (10') for the levelling cylinders (10).
16. Paver according to at least one of Claims 7 to 15, characterised in that an actuating member, preferably for adjusting a screed relief, is a solenoid-operated valve (28') for the lifting cylinders (28).

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