EP3399105B1 - Soil compaction device - Google Patents

Description

The invention relates to a soil compaction device with a superstructure and an undercarriage with a vibrating plate and a plurality of exciter units, wherein at least a part of the exciter units can each be driven individually by a drive.

State of the art

Usually have Bodenverdichtungsgeräte with a vibrating plate, such as a vibrating plate, an internal combustion engine for driving two similar, parallel, rigidly coupled via a gear and counter-rotating unbalanced shafts. The opposite rotation of the unbalanced shafts operated with the same number of revolutions causes the centrifugal forces generated by the imbalances to mutually reinforce or compensate depending on the phase angle. By a suitable adjustment of the respective phase position of the imbalances to one another results in a resulting force vector, which can be used for locomotion and / or compression. In this case, a vibrating plate usually has a hydraulic system for adjusting the phase position of the mechanically coupled to each other waves. Often this is done by means of an axially displaceable spiral shaft.

Since the force vector resulting from superimposition is always oriented perpendicular to the axis of rotation of the imbalance shafts, the drive direction is limited to further forward and reverse travel without further measures.

To improve the steering characteristics is from the DE 10 2006 000786A1 discloses a plate compactor having a plurality of exciter units for forming a force vector, wherein the individual exciter units, for example, operate according to the principle described above. Among other things, the large number of exciter units also permits the formation of force vectors which act in the lateral direction. However, the multiplicity of excitation units considerably increases the mechanical complexity.

Furthermore, the describes DE 10 2005 029433 A1 an operation of a vibrating plate with a plurality of individual exciters. These are individually controllable and are operated by located on the vibration plate hydraulic motors. However, the arranged on the vibrating plate hydraulic motors are complex and also exposed to very high mechanical stresses.

Disclosure of the invention

Object of the present invention is to provide a cost-effective and reliable solution for a comfortable soil compaction device with a finely tuned and precise steering that allows easy control of the soil compaction device in each direction of the plate plane.

The object is achieved according to the invention by the features of the independent claim. Advantageous embodiments of the invention are specified in the subclaims.

According to the invention, a ground compaction device is provided with a superstructure and an undercarriage, wherein the undercarriage has a vibration plate and a plurality of excitation units, wherein at least a part of the exciter units of each drive is individually driven and each having at least one vibration exciter, which with a measuring device for Detection of its phase position is connected, wherein the phase position of a control / regulating device is fed,
and wherein individual vibration exciter are coupled to each other via an elastic element, a respective electrically controllable drive and the control / regulating device and the relative phase position of the individual vibration exciter to each other via the control / regulating device is adjustable.

At least two of the excitation units are each individually driven by a respective drive and each have at least one vibration exciter. In this case, an exciter unit can have one or two opposite, coupled to each other vibration exciter. A vibration exciter may for example consist of an imbalance shaft and a rotating imbalance or an oscillator with an oscillating mass. Advantageously, an exciter unit has exactly one vibration exciter with an imbalance shaft and a rotating imbalance.

Furthermore, the control unit can advantageously consist of a higher-level control device and a plurality of control devices controlled by the control device, wherein in each case one connected to a measuring device vibration exciter each having a control device and the detectable by the respective measuring means phase positions the respective control means are supplied. In this embodiment, each vibration exciter on its own control circuit for controlling its phase position, which is the respective control device can be specified as a reference variable. The phase angle of at least two vibration exciters to each other is electrically variable. The change in the phase position of at least one individual vibration exciter can be changed relative to the phase position of another or further vibration exciter by changing its desired phase position as a reference variable. The desired phase position can be predetermined by the control device, for example as a result of the conversion of a steering command supplied to the control device.
The vibration exciters are each connected via an elastic element with the respective electric drive. A deviation of an actual phase position from a desired phase position due to the elastic connection can be compensated by the control device. A coupling of the phase position between two vibration exciters is given via at least one elastic element and the phase position of at least one of the vibration exciters coupled via an elastic element can be regulated via a regulating device. Such a structure enables a simple and modular construction of the control unit.

In other words, by way of example, a soil compacting device is provided, the vibrating plate of which has a plurality of electrically driven and electrically controllable exciter units. In this case, for example, the electric drives are each connected in each case via an elastic element with the respective vibration exciters.

Such an arrangement has several advantages. The arrangement of a plurality of exciting units on the vibrating plate offers the possibility to arrange them in different orientations and to generate force vectors in each direction by appropriate activation. Different numbers of structurally identical exciter units can be used for the modular production of soil compactors of different weight classes, and / or on the other hand an optimization of the distribution can be achieved by distributing their orientations on the vibrating plate, for example by distributing the orientation according to the distribution of an intensity of movement directions Steering assets are achieved.

Furthermore, the use of electric drives has the advantage that electrical leads compared to other supply lines such as hydraulic hoses, have a very good fatigue life and thus are more resistant to wear.

Furthermore, the use of an elastic element between the drive, or its drive shaft and the imbalance shaft has the advantage that it acts dampening and vibrations of the imbalance shaft act less on the electric drives.

In this case, the loss of the rigid coupling between the imbalance shafts occurring in comparison to the conventional exciters can be at least partially compensated by a fast-response, precise electrical regulation.

According to the invention, the phase position of at least one of the unbalanced shafts or oscillators coupled via an elastic element can be regulated by way of a regulating device.

An excitation unit has a measuring device connected to the vibration exciter for detecting the phase position of the vibration exciter. If this is designed in the form of an imbalance wave, the phase angle of the measuring device can be detected by the measurement of the phase angle.

The measuring device is able to detect the phase angle of the unbalance with respect to a zero position, for example, the gravitational rest position in the freewheel, and pass it as a phase to the control device. The control device is set up to set the manipulated variables of the drive to achieve a desired phase position. Thus, it is able to change the phase angle between two unbalanced shafts or oscillators, or to set a predetermined phase position. Advantageously, at least a part of the exciter units each individually assigned a control device. By a higher-level control device, the individually assigned control devices can be given their respective desired phase position as a reference variable

The drive is electrically designed. Likewise, the measuring device advantageously has an encoder for the digital processing of the measured values. Advantageously, the measuring device of the control device in addition to the phase position and the angular velocity of a shaft available.

The inventively provided attenuation of the electric drives relative to the imbalance shaft reduces the demands on the capacity of the electric drives, in particular their vibration resistance, and allows the use of comparatively simple and inexpensive components.

Advantageously, the electric drives are arranged in the superstructure, the vibration exciter arranged in the undercarriage, and the electric drives in the superstructure in each case individually by means of one elastic element, advantageously a belt, each connected to a vibration exciter in the undercarriage. In this way, the stress of the electric drives can be reduced by about one order of magnitude and the life of the electric drives can be extended accordingly.

Advantageously, the exciter units have exactly one vibration exciter with a single imbalance shaft. Such a configuration is low maintenance and inexpensive to implement.

Advantageously, at least for some of the excitation units, the electric drive is designed as a substantially individual electric motor. Electric motors are simple and inexpensive to produce, a use of a plurality of the same electric motors for the majority of excitation units promotes through the use of similar components, the rationalization of the production. Alternatively, a single electric drive can also be designed as an electrical coupling, which is designed to partially divert a drive energy of a superordinate drive and to individualize it in terms of phase position and angular velocity.

Advantageously, the electric drive is designed as a stepper motor. A stepper motor has the advantage that the angular position and thus the phase angle of the drive shaft is adjustable and thus can be assumed to be known. In an arrangement in which the measuring device for detecting the phase position, seen in the effective direction of the drive, is arranged directly on the drive shaft in front of the elastic element, a stepper motor can take over the function of the measuring device. The execution of a measuring device as an independent component can be omitted in this case, the measuring device can be considered in this case as integrated into the stepper motor. Furthermore, a stepper motor is vibration resistant executable.

Further advantageously, a control device is designed as a PI or PID controller. The connection of the imbalance shaft with the electric drive via an elastic element leads to a change in the angular velocity to an energy absorption of the elastic element, which returns this energy with a time delay to the arrangement. In knowledge of the step response of the controlled system, consisting of electric drive, drive shaft, elastic Element and imbalance shaft including the imbalance, it is possible to control the electric drive by a control device such that overshoot of the imbalance shaft is reduced or avoided. Advantageously, a control device is designed to minimize a transient of an excitation unit after a phase or frequency change.

The measuring device for detecting the phase position can be arranged in front of the elastic element on the drive shaft, or behind the elastic element on the imbalance shaft. An arrangement of the measuring device on the imbalance shaft of a vibration exciter in the undercarriage of the soil compaction device offers the advantage that a control device, the actual phase angle and angular velocity of the imbalance shaft can be supplied.

In an arrangement of the measuring device on the drive shaft, the measuring device is connected only indirectly via the elastic element with the imbalance shaft, so that due to a spring action of the elastic element, the determined phase angle and angular velocity may differ slightly from the actual phase angle and angular velocity of the unbalanced shaft.
Knowing the step response of the controlled system and the spring constant of the elastic element and the mass of the imbalance shaft, the deviation between the measured and the actual phase position can be estimated by the control device.

The directions of rotation, angular velocities and phase positions of the vibration exciter form in their superposition a translational and / or rotational moment with respect to a standing surface of the soil compaction device. This translational and / or rotational moment can be used for locomotion and steering.

Advantageously, the vibration exciter are arranged angularly, in particular star-shaped on the vibration plate. A symmetrical arrangement at equal angles allows for a control device, for example, a steering command in respective desired phase positions as command values for the respective Vibratory exciter, a simple calculation of the required control values to produce a desired translational and / or rotational moment. In this case, the input of a steering command, for example, by means of a movable control in two axes control stick as part of a manual control. Furthermore, the hand control may be an integral part of the soil compaction device or a remote control.

Advantageously, a control device is designed as a digital controller. Digital controllers can be implemented quickly enough and offer great flexibility in terms of their controller characteristics. Advantageously, a control device has a digital controller which has a predistorter for generating the manipulated variables for the electric drive, which causes such temporal predistortion of the manipulated variables that transient oscillation due to a phase or frequency change is avoided or reduced. Advantageously, the control device is set up to compensate for vibrations which are enabled or favored by the elastic element.

Advantageously, the predistortion of the manipulated variables or setting of the parameters of a PI or PID controller based on the step response of the controlled system. Knowing the parameters of the step response, for example its inflection point, the parameters of a PI or PID controller are according to adjustment rules known in the literature, e.g. according to Ziegler / Nichols, dimensionable.

Advantageously, the soil compaction device has a calibration mode for determining the step response, in which the step response of the controlled system, for example after a belt change, can be determined. In such a mode, the control loop can be opened and the reaction of the vibration exciter in response to a steering movement or a change in the phase position of the vibration exciter can be determined and stored.

Further advantageously, a control device is designed to jointly evaluate the measured values of a plurality of measuring devices and to optimize the manipulated variables for the electric drives of a plurality of vibration exciters in such a way that undesired oscillation of the soil compacting device is avoided or reduced.

The various excitation units are coupled together via the vibrating plate, so that they stimulate each other to vibrate, there are energy balancing operations on. Due to this coupling, the individual control circuits for adjusting the phase position are not completely decoupled.

Advantageously, the soil compaction device has a control device which is designed to jointly evaluate the phase positions of a plurality of vibration devices and to optimize the manipulated variables for a plurality of vibration exciters such that a translational or rotational movement desired by the user is converted to phase changes of the vibration exciters such that the height of the phase jumps is minimized. In this case, the optimization could, for example, be carried out in accordance with the method of minimum squares of the error such that, while maintaining the resulting motion vector, it is not the control difference of individual control loops that is minimized but the magnitude of the control difference vector. Such an optimization is possible in particular if a large number of vibration exciters is available and different selections of vibration exciters contributing to the formation of a specific common force vector are possible.

drawings

The invention will be explained in more detail below with reference to the attached, schematic drawings based on preferred embodiments.

Fig. 1

eine Skizze zum Prinzip des Bodenverdichtungsgeräts;

Fig. 2

eine bevorzugte Anordnung von Erregereinheiten auf einer Vibrationsplatte bei einer Anordnung der Messeinrichtung auf der Unwuchtwelle;

Fig. 3

die bevorzugte Anordnung von Erregereinheiten bei einer Anordnung der Messeinrichtung auf der Antriebswelle;

Fig. 4

ein Prinzipschaltbild zur Regelung einer Erregereinheit bei einer Anordnung der Messeinrichtung auf der Antriebswelle;

Fig. 5

ein Prinzipschaltbild zur Regelung einer Erregereinheit bei einer Anordnung der Messeinrichtung auf der Unwuchtwelle;

Fig. 6

ein Prinzipschaltbild zur Kopplung zwei einzelner Vibrationserreger über jeweils ein elastisches Element, einen jeweiligen elektrisch steuerbaren Antrieb und eine elektronische Steuereinrichtung;

Fig. 7

ein Prinzipschaltbild zur gemeinsamen Regelung der Erregereinheiten.

Show it

Fig. 1

a sketch of the principle of Bodenverdichtungsgeräts;

Fig. 2

a preferred arrangement of exciter units on a vibrating plate in an arrangement of the measuring device on the imbalance shaft;

Fig. 3

the preferred arrangement of exciter units in an arrangement of the measuring device on the drive shaft;

Fig. 4

a schematic diagram for controlling an exciter unit in an arrangement of the measuring device on the drive shaft;

Fig. 5

a schematic diagram for controlling an excitation unit in an arrangement of the measuring device on the imbalance shaft;

Fig. 6

a schematic diagram for coupling two individual vibration exciter via a respective elastic element, a respective electrically controllable drive and an electronic control device;

Fig. 7

a schematic diagram for the common control of the exciter units.

Fig. 1 shows a sketch of the principle of a soil compaction device 1 with a superstructure 2 and an undercarriage 3, wherein the undercarriage 3 has a vibration plate 4 and a plurality of exciter units 5. The exciter units 5 each have a vibration exciter arranged in the undercarriage 3 on the vibrating plate 4 in the form of an imbalance shaft 7 and are connected via an elastic element 9 in the form of a belt to a drive 6 arranged in the superstructure 2.

Fig. 2 shows a preferred arrangement of exciter units 5 on a vibrating plate 4 in an arrangement of the measuring devices 8 on the imbalance shaft 7. The exciter units 5 are arranged in a star shape and axisymmetric to each other. The axes of rotation of their unbalanced shafts 7 are in diagonally arranged exciter units 5 on a straight line. The notionally extended axes of rotation of all unbalanced shafts 7 intersect at a point which is located approximately centrally on the vibrating plate 4.

Further shows Fig. 2 The excitation units 5 are individually driven by an electric drive 6 and each have a vibration exciter with an imbalance shaft. 7 and a rotating unbalance 10 and connected to the vibration exciter measuring device 8 for detecting the phase position of the imbalance shaft 7. The phase position of the vibration exciter is equated with the phase position of its imbalance shaft 7. The measuring device 8 is arranged in the direction of the action of the drive, that is, in the direction of the imbalance shaft 7 behind the elastic element 9. The electric drive 6 is preferably arranged in the superstructure 2, but it may also be arranged in the undercarriage 3 together with the vibration exciter on the vibration plate 4.

Fig. 3 shows the same preferred arrangement of excitation units 5 on a vibrating plate 4 in an arrangement of the measuring devices 8 on the drive shaft of the electric drive 6. The only difference to Fig. 2 is the measuring device 8 in the direction of the action of the drive, that is arranged in the direction of the imbalance shaft 7, in front of the elastic element 9.

Fig. 4 shows a schematic diagram for controlling an exciter unit 5 in an arrangement of the measuring device 8 on the drive shaft. In the illustrated embodiment, the measuring device 8 is arranged in the upper carriage 2 and set up for direct detection of the phase position of the electric drive 6. The imbalance shaft 7 may have a slightly different phase position from this phase, the difference to the detected phase position is not constant, but which may vary in time as a function of changes in the rotational speed of the drive 6 or by the transmission of vibrations to the imbalance shaft 7. Knowing the mass ratios, the spring constant of the elastic element 9 and the time course of phase position and speed, the controller 12 can estimate the deviation of the phase position of the imbalance shaft 7 of the phase angle of the drive shaft.

The detectable by the measuring device 8 phase position of the drive shaft can be supplied as actual phase position and feedback variable of a control loop of the control device 12. By determining the deviation to a predetermined by a parent control device 11 target phase position as a reference variable is a manipulated variable determined by the control device 12 and a motor controller 13 can be fed. Depending on the design of the electric drive 6, for example as an asynchronous or stepper motor, the motor controller 13 converts the manipulated variable into corresponding control voltages or signals for the phase or speed change of the electric drive 6.

Fig. 5 shows a schematic diagram for controlling an excitation unit 5 in an arrangement of the measuring device 8 on the imbalance shaft 7. In the illustrated embodiment, the measuring device 8 is arranged in the undercarriage 3 and set up for direct detection of the phase position of the imbalance shaft 7. This is different from Fig. 4 the actual actual phase position of the imbalance shaft 7 directly comparable to the desired phase position. At the same time, the elastic element 9 with its time behavior Δφ (t) is part of the controlled system. If the control device 12 is set up to generate a manipulated variable taking into account a known step response of the controlled system, and if the electric drive 6 is sufficiently fast to respond appropriately to a manipulated variable change, precise control of the phase position of the imbalance shaft 7 is achieved by compensating the time behavior Δφ (FIG. t) of the elastic element 9 possible.

Fig. 6 shows a schematic diagram for coupling two individual vibration exciter via one elastic element 9, 9 ', a respective electrically controllable drive 6, 6', a respective control device 12, 12 'and a higher-level control device 11; By the higher-level control device 11, the vibration exciters of the exciter units 5, 5 'with individually associated control devices 12, 12' their respective desired phase position can be set as a reference variable, so that between the unbalanced shafts 7, 7 'of the vibration exciter a relative phase Δφ is adjustable.

Fig. 7 shows a block diagram for the common control of example four exciter units 5 via a control device 14. Wie aus Fig. 6 it can be seen that the phase positions of several measuring devices 8 are supplied together as the actual size vector of a control / regulating device 14. Due to the mechanical connection via the common vibration plate 4, the vibration exciter 5 are parasitically coupled to each other, wherein the degree of coupling additionally depends on the orientation of the vibration-generating elements of the vibration exciter 5.

Taking into account the couplings of the control circuits, the control unit 14 calculates a manipulated variable vector whose coefficients are supplied to the individual motor controllers 13.

In this case, the calculation of the manipulated variable vector for the plurality of control loops can be optimized in such a way that high phase jumps for individual control loops are avoided, or that the magnitude of the control difference vector is minimized while maintaining the resulting motion vector.

Claims (14)

1. A soil compaction machine (1) comprising an upper carriage (2) and an undercarriage (3), wherein the undercarriage (2) comprises a vibratory plate (4) and a plurality of excitation units (5), wherein at least some of said excitation units (5) can each be individually driven by a respective drive (6), and each has at least one vibration exciter that is connected to a measuring means (8) for detecting the phase position of said exciter, wherein the phase position is able to be conveyed to a control/regulating means (14),
   characterised in that
   the individual vibration exciters are each coupled together via an elastic member (9), an electrically controllable drive (6) and the control/regulating means (14), and the relative phase position of the individual vibration exciters with respect to one another is adjustable by way of the control/regulating means (14).
2. The soil compaction machine (1) according to claim 1, characterised in that the control/regulating means (14) comprises a superordinate control means (11) and a plurality of regulating means (12) controlled by said control means (11), wherein each vibration exciter that is connected to a measuring means (8) is associated with a respective regulating means (11), and the relevant phase positions detectable by the respective measuring means (8) are able to be conveyed to each of the regulating means (11).
3. The soil compaction machine (1) according to claim 1 or claim 2, characterised in that at least some of said excitation units (5) can each be individually and electrically driven by a drive (6), and the control/regulating means (14) or a regulating means (12) is designed to minimise overshoot in an excitation unit (5) following a phase or frequency change.
4. The soil compaction machine (1) according to any of the preceding claims, characterised in that the undercarriage (3) is elastically connected to the upper carriage (2), the upper carriage (2) comprises a plurality of electrical drives (6), and the vibration exciters on the undercarriage (3) are each connected to one of the electric drives (6) via an elastic member (9).
5. The soil compaction machine (1) according to any of the preceding claims, characterised in that the vibration exciters comprise a single eccentric shaft (7).
6. The soil compaction machine (1) according to any of the preceding claims, characterised in that, in at least some of the excitation units (5), the electric drive (6) is in each case essentially designed by way of an electric motor, in particular a stepper motor, the elastic member (9) is in each case designed as a belt, the vibration exciter in each case comprises an eccentric shaft (7), and the measuring means (8) is in each case arranged on the undercarriage (3).
7. The soil compaction machine (1) according to any of the preceding claims, characterised in that the vibration exciters are arranged on the vibratory plate (4) at angles, in particular in the shape of a star, and that, by way of a control means (11), the directions of rotation, angular velocities, and phase positions of the vibration exciters are, by way of superposition, adjustable in a way that generates a translational and/or rotational torque with respect to a footprint of the soil compaction machine (1).
8. The soil compaction machine (1) according to any of claims 2 to 7, characterised in that at least some of the vibration exciters are each associated with a regulating means (12).
9. The soil compaction machine (1) according to any of the preceding claims, characterised in that the control/regulating means (14) or a regulating means (12) is designed as a PI controller or a PID controller.
10. The soil compaction machine (1) according to any of the preceding claims, characterised in that the control/regulating means (14) or a regulating means (12) is designed as a digital controller, and the regulating means (12, 14) comprises a predistorter used to generate manipulated variables for the electric drive (6), said distorter causing time-related predistortion of the manipulated variables so as to prevent or minimise overshoot resulting from a phase or frequency change.
11. The soil compaction machine (1) according to claim 10, characterised in that said predistortion takes place on the basis of the step response in the regulation circuit.
12. The soil compaction machine (1) according to claim 11, characterised in that the soil compaction machine (1) has a calibration mode in which the step response in the regulation circuit is able to be determined by the soil compaction machine (1), in particular following replacement of the elastic member (9).
13. The soil compaction machine (1) according to any of the preceding claims, characterised in that the control/regulating means (14) is designed to collectively evaluate the values measured by a plurality of measuring means (8) and to optimise the manipulated variables for the electric drives (6) of a plurality of vibration exciters in a way that prevents or minimises undesired oscillation of the soil compaction machine (1).
14. The soil compaction machine (1) according to any of the preceding claims, characterised in that the control/regulating means (14) is designed to collectively evaluate the values measured by a plurality of measuring means (8) and to optimise the manipulated variables for a plurality of vibration exciters, with the result that translational or rotational motion desired by the operator is converted into phase changes of the vibration exciters in a way that minimises the intensity of phase jumps.

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