ELECTROHYDRAULIC CONTROL DEVICE AND ADJUSTABLE HYDRAULIC PUMP SYSTEM

Abstract

An electrohydraulic control device for an adjustable hydraulic pump system includes a valve device, an electronic control unit and a first fluid sensor. The valve device includes a pressure inlet, a tank outlet and a first electromagnetically actuated valve. An outlet pressure of the first adjustable hydraulic pump system is applied to the pressure inlet. The first fluid sensor detects an actual value of a fluid parameter of the first adjustable hydraulic pump system and transmits it to the electronic control unit. The electronic control unit includes computer-based modeling of the dynamics of the first adjustable hydraulic pump system, and actuates the first electromagnetically actuated valve based on the actual value of the fluid parameter and the computer-based modeling.

Claims

1. An electrohydraulic control device for an adjustable hydraulic pump system, comprising: a valve device; an electronic control unit; and at least one first fluid sensor, wherein the valve device comprises a pressure inlet, a tank outlet and a first electromagnetically actuated valve, and an outlet pressure of the adjustable hydraulic pump system is applied to the pressure inlet of the valve device, wherein the first fluid sensor detects the actual value of a fluid parameter of the adjustable hydraulic pump system and transmits the actual value of the fluid parameter to the electronic control unit, wherein the electronic control unit comprises a computer-based modeling of the dynamics of the adjustable hydraulic pump system and actuates the first electromagnetically actuated valve based on the actual value of the fluid parameter and the computer-based modeling.

2. The electrohydraulic control device according to claim 1, wherein the fluid parameter is the output pressure or an output volume flow of the adjustable hydraulic pump system.

3. The electrohydraulic control device according to claim 1, wherein the computer-based modeling of the dynamics of the adjustable hydraulic pump system comprises an artificial neural network.

4. The electrohydraulic control device according to claim 1, wherein the first electromagnetically actuated valve is a first proportional valve or a first switching valve.

5. The electrohydraulic control device according to claim 1, wherein the first fluid sensor is integrated in the first electromagnetically actuated valve.

6. The electrohydraulic control device according to claim 1, wherein the valve device further comprises a control outlet connected to an actuator of the adjustable hydraulic pump system, wherein a first hydraulic connection is formed between the pressure inlet and the control outlet, and a second hydraulic connection is formed between the control outlet and the tank outlet.

7. The electrohydraulic control device according to claim 6, wherein the valve device further comprises a second electromagnetically actuated valve, wherein the first electromagnetically actuated valve is disposed in the first hydraulic connection (10) and the second electromagnetically actuated valve is disposed in the second hydraulic connection, wherein the electronic control unit actuates the second electromagnetically actuated valve based on the actual value of the fluid parameter and the computer-based modeling.

8. The electrohydraulic control device according to claim 7, wherein the second electromagnetically actuated valve is a second proportional valve or a second switching valve.

9. The electrohydraulic control device according to claim 7, wherein the electrohydraulic control device further comprises at least one second fluid sensor, the second fluid sensor being integrated in the second electromagnetically actuated valve.

10. The electrohydraulic control device according to claim 6, wherein the valve device further comprises a hydraulic resistor, wherein the first electromagnetically actuated valve is disposed in the first hydraulic connection and the hydraulic resistor is disposed in the second hydraulic connection.

11. The electrohydraulic control device according to claim 6, wherein the valve device further comprises a hydraulic resistor, wherein the hydraulic resistor is disposed in the first hydraulic connection and the first electromagnetically actuated valve is disposed in the second hydraulic connection.

12. The electrohydraulic control device according to claim 6, wherein the electrohydraulic control device further comprises an actuating angle sensor.

13. An adjustable hydraulic pump system comprising an electrohydraulic control device according to claim 1.

14. The adjustable hydraulic pump system according to claim 13, wherein the adjustable hydraulic pump system comprises an adjustable pump with a control piston and a soft sensor volume flow determination is implemented in the control unit.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The invention is explained in more detail below with reference to embodiments shown in the figures. Herein schematically

[0036] FIG. 1 is a circuit diagram of a first adjustable hydraulic pump system with an electrohydraulic control device according to the invention in accordance with a first embodiment;

[0037] FIG. 2 is a circuit diagram of a second adjustable hydraulic pump system with an electrohydraulic control device according to the invention in accordance with a second embodiment;

[0038] FIG. 3a is a first variant of a valve device of the electrohydraulic control device according to the first and second embodiments;

[0039] FIG. 3b is a second variant of the valve device of the electrohydraulic control device according to the first and second embodiments;

[0040] FIG. 4a is a third variant of the valve device of the electrohydraulic control device according to the first and second embodiments;

[0041] FIG. 4b is a fourth variant of the valve device of the electrohydraulic control device according to the first and second embodiments;

[0042] FIG. 5a is a fifth variant of the valve device of the electrohydraulic control device according to the first and second embodiments;

[0043] FIG. 5b is a sixth variant of the valve device of the electrohydraulic control device according to the first and second embodiments;

[0044] FIG. 6 is a seventh variant of the valve device of the electrohydraulic control device according to the first and second embodiments;

[0045] FIG. 7 is an eighth variant of the valve device of the electrohydraulic control device according to the first and second embodiments;

[0046] FIG. 8 is a ninth variant of the valve device of the electrohydraulic control device according to the first and second embodiments;

[0047] FIG. 9a is a tenth variant of the valve device of the electrohydraulic control device according to the first and second embodiments;

[0048] FIG. 9b is an eleventh variant of the valve device of the electrohydraulic control device according to the first and second embodiments;

[0049] FIG. 10a is a circuit diagram of a third adjustable hydraulic pump system with an electrohydraulic control device according to a third embodiment with a first variant of a valve device; and

[0050] FIG. 10b is a second variant of the valve device of the electrohydraulic control device according to the third embodiment.

DETAILED DESCRIPTION OF THE INVENTION

[0051] FIG. 1 shows a schematic circuit diagram of a first adjustable hydraulic pump system 100 with an electrohydraulic control device 1 according to the invention in accordance with a first embodiment and a fluid outlet F to which a higher-level hydraulic system is connected (not shown).

[0052] The electrohydraulic control device 1 comprises a valve device 2, an electronic control unit 3 and a first fluid sensor 4. The valve device 2 comprises a pressure inlet P, a tank outlet T and a first electromagnetically actuated valve 5 (cf., for example, FIGS. 3a to 9b). An output pressure of the first adjustable hydraulic pump system 100 is applied to the pressure inlet P of the valve device. The first fluid sensor 4 detects the actual value of a fluid parameter of the first adjustable hydraulic pump system 100 and transmits the actual value of the fluid parameter to the electronic control unit 3 in a known manner, for example via a (not shown) signal line or via a wireless connection. Thereby, the electronic control unit 3 comprises a computer-based modeling of the dynamics of the first adjustable hydraulic pump system 100 and actuates the first electromagnetically actuated valve 5 based on the actual value of the fluid parameter and the computer-based modeling.

[0053] In the present embodiment, the fluid parameter sensed by the first fluid sensor 4 is the output pressure of the first adjustable hydraulic pump system 100. Thus, the first fluid sensor 4 is a first electronic pressure sensor. However, the first fluid sensor 4 may also sense an output volume flow of the first adjustable hydraulic pump system 100. In this case, the first fluid sensor 4 is a first volume flow sensor. It is also conceivable that the first fluid sensor 4 is a combined pressure and volume flow sensor.

[0054] The computer-based modeling of the dynamics of the first adjustable hydraulic pump system 100 includes an artificial neural network.

[0055] FIGS. 3a to 8 show different variants of the valve device 2 according to the first embodiment of the electrohydraulic control device 1, in which corresponding variants of the first electromagnetically actuated valve 5 can be seen.

[0056] According to the first variant of the valve device 2, the first electromagnetically actuated valve 5 is a 2/2 proportional directional control valve (cf. FIG. 3a). According to the second variant of the valve device 2, the first electromagnetically actuated valve 5 is a 2/2 switching directional control valve (cf. FIG. 3b). According to the third variant of the valve device 2, the first electromagnetically actuated valve 5 is a 2/2 proportional seat valve (cf. FIG. 4a). According to the fourth variant of the valve device 2, the first electromagnetically actuated valve 5 is a 2/2 switching seat valve (cf. FIG. 4b). According to the fifth and sixth variants of the valve device 2, the first electromagnetically actuated valve 5 is a 4/3 proportional seat valve in which one port is blocked in each case (cf. FIGS. 5a and 5b). According to the seventh variant of the valve device 2, the first electromagnetically actuated valve 5 is a 3/3 proportional directional control valve (cf. FIG. 6). According to the eighth variant of the valve device 2, the first electromagnetically actuated valve 5 is a 3/2 proportional directional control valve (cf. FIG. 7). According to the ninth variant of the valve device 2, the first electromagnetically actuated valve 5 is a proportional pressure relief valve (cf. FIG. 8). The first electromagnetically actuated valve 5 is also biased by a spring force in each variant, as can be seen in the figures.

[0057] As shown schematically by way of example in FIG. 3a for the 2/2 proportional directional control valve, the first fluid sensor 4 can also be integrated in the first electromagnetically actuated valve 5. It is obvious to the person skilled in the art that the first fluid sensor 4 can also be integrated in the first electromagnetically actuated valve 5 in all further variants of the first electromagnetically actuated valve 5 shown in the figures.

[0058] As shown in FIG. 1, the valve device 2 of the electrohydraulic control device 1 according to the first embodiment further comprises a control outlet A. The control outlet A is connected to an actuator of the first hydraulic pump system 100. The first adjustable hydraulic pump system 100 comprises an adjustable pump 8 with an control piston 9. The control piston 9 is the actuator of the first adjustable hydraulic pump system 100 (cf. FIG. 1).

[0059] As can be seen in FIGS. 3a to 9b, in the valve device 2 of the first embodiment of the electrohydraulic control device 1, a first hydraulic connection 10 is formed between the pressure inlet P and the control outlet A. In addition, a second hydraulic connection 11 is formed between the control outlet A and the tank outlet T. The first hydraulic connection 10 is here an inlet of the valve device 2 and the second hydraulic connection 11 is here an outlet of the valve device 2.

[0060] As shown in FIGS. 3a, 3b, 4a, 4b, and 8, the valve device 2 according to the variants shown in these figures further comprises a second electromagnetically actuated valve 12, wherein the first electromagnetically actuated valve 5 is disposed in the first hydraulic connection 10 and the second electromagnetically actuated valve 12 is disposed in the second hydraulic connection 11.

[0061] According to the first variant of the valve device 2, the second electromagnetically actuated valve 12 is a 2/2 proportional directional control valve (cf. FIG. 3a). According to the second variant of the valve device 2, the second electromagnetically actuated valve 12 is a 2/2 switching directional control valve (cf. FIG. 3b). According to the third variant of the valve device 2, the second electromagnetically actuated valve 12 is a 2/2 proportional seat valve (cf. FIG. 4a). According to the fourth variant of the valve device 2, the second electromagnetically actuated valve 12 is a 2/2 switching seat valve (cf. FIG. 4b). According to the ninth variant of the valve device 2, the second electromagnetically actuated valve 12 is a proportional pressure relief valve (cf. FIG. 8). The second electromagnetically actuated valve 12 is also biased by a spring force in each variant, as can be seen in the figures.

[0062] As shown schematically by way of example in FIG. 3a for the 2/2 proportional directional control valve, the electrohydraulic control device 1 can further comprise a second fluid sensor 13 which is integrated in the second electromagnetically actuated valve 12. In this regard, it is obvious to the person skilled in the art that also in all further variants of the second electromagnetically actuated valve 12 shown in the figures, the second fluid sensor 13 may be integrated in the second electromagnetically actuated valve 12. In the present case, the second fluid sensor 13 is a pressure sensor to the tank.

[0063] The artificial neural network of the electronic control unit 3 is fed with training data such as the output pressure of the first adjustable hydraulic pump system 100, a pressure at the control piston 9, and a energization of the first electromagnetically actuated valve 5. If the valve device 2 comprises the second electromagnetically actuated valve 12, the training data also includes an energization of the second electromagnetically actuated valve 12. The artificial neural network of the electronic control unit 3 processes the measurement signals of the first fluid sensor 4 and, if applicable, the second fluid sensor 13 in combination with its training data to calculate a prediction of the output pressure of the first adjustable hydraulic pump system 100. Thus, the electronic control unit 3 implements an adaptive, robust control for the adjustable hydraulic pump system 100.

[0064] The electrohydraulic control device 1 according to the invention is thus configured, for example, to control the output pressure of the first adjustable pump system 100 applied to the fluid outlet F (cf. FIG. 1). The output pressure is thus to be adjusted to a reference variable. In this context, the valve device 2 comprises, for example, as shown in FIG. 3a, a first electromagnetically actuated 2/2 proportional directional control valve 5 with integrated first fluid sensor 4 and a second electromagnetically actuated 2/2 proportional directional control valve 12 with integrated second fluid sensor 13. The electronic control unit 3 thus receives the sensor data from at least the first fluid sensor 4, which detects the actual value of the output pressure, and the second fluid sensor 13, which detects the actual value of the pressure in the direction of the tank. In addition, the electronic control unit 3 can, for example, receive sensor data from a positioning angle sensor 15 of the variable displacement pump 8 or other sensors present in the higher-level hydraulic system.

[0065] In combination with the computer-based modeling of the dynamics of the first adjustable hydraulic pump system 100, the electronic control unit 3 processes the sensor data obtained to actuate the valve device 2. The actual value of the output pressure is compared with the reference variable to be controlled and a currently present control error is calculated. Based on this control error, the electronic control unit 3 calculates the control variables required to provide the required command variable.

[0066] Specifically, the electronic control unit 3 calculates as control variables the current flow of the first electromagnetically actuated 2/2 proportional directional control valve 5 and the current flow of the second electromagnetically actuated 2/2 proportional directional control valve 12, which is necessary to control the desired outlet pressure at the fluid outlet F. The command variables here are therefore the switching states of the two valves. Via the respective energization, the first electromagnetically actuated 2/2 proportional directional control valve 5 and the second electromagnetically actuated 2/2 proportional directional control valve 12 are switched in such a way that the pressure applied to the control outlet A moves the control piston 9 of the variable displacement pump 8 in such a way that the variable displacement pump 8 supplies the geometric displacement volume required to set the desired output pressure at the fluid output F. The output pressure at the fluid output F is set to the desired value. The output pressure at fluid outlet F is used to actuate the variable displacement piston 9 via control outlet A by means of pressure inlet P. The second electromagnetically actuated 2/2 proportional directional control valve 12 is thereby regularly opened by the electronic control unit 3 only for small flow rates of the variable displacement pump 8 to the tank outlet T and not for larger flow rates in order to control the hydraulic losses to a minimum. However, the electronic control unit 3 always gives priority to controlling the control error to a minimum before controlling the hydraulic losses.

[0067] As shown schematically in FIGS. 9a and 9b, in a tenth and eleventh variant the valve device 2 comprises a hydraulic resistor 14. The hydraulic resistor 14 may be a fixed throttle or a fixed nozzle. However, it is also conceivable to use an adjustable hydraulic resistor, i.e. an adjustable throttle or nozzle.

[0068] According to the tenth variant of the valve device 2, the first electromagnetically actuated valve 5 is disposed in the first hydraulic connection 10 and the hydraulic resistor is disposed in the second hydraulic connection (cf. FIG. 9a). According to the eleventh variant of the valve device 2, the hydraulic resistor 14 is disposed in the first hydraulic connection 10 and the first electromagnetically actuated valve 5 is disposed in the second hydraulic connection 11 (cf. FIG. 9b).

[0069] As can be further seen in FIG. 1, the electrohydraulic control device 1 according to the first embodiment further comprises a positioning angle sensor 15. The positioning angle sensor 15 detects the positioning angle of the variable displacement pump 8, which is set by the control piston 9, and transmits this to the electronic control unit 3.

[0070] The transmission of signals to the electronic control unit 3 by the first fluid sensor 4, the second fluid sensor 13 and the actuating angle sensor 15 is carried out in a generally known manner either wired or wireless.

[0071] With reference to FIG. 2, an electrohydraulic control device 1′ according to the invention will now be described in accordance with a second embodiment. The electrohydraulic control device 1′ according to the second embodiment differs from the electrohydraulic control device 1 according to the first embodiment only in the features described below. Consequently, the above description of the remaining features of the electrohydraulic control device 1 according to the first embodiment refers in an identical manner to the electrohydraulic control device 1′ according to the second embodiment.

[0072] FIG. 2 shows a second adjustable hydraulic pump system 200 comprising a fixed displacement pump 16, a first recirculating valve device 17 and the electrohydraulic control device 1′ according to the second embodiment.

[0073] The electrohydraulic control device 1′ according to the second embodiment comprises the valve device 2, an electronic control unit 3′ and the first fluid sensor 4. The valve device 2 comprises the pressure inlet P, the tank outlet T and the first electromagnetically actuated valve 5. The pressure inlet P of the valve device 2 is pressurized with an output pressure of the second adjustable hydraulic pump system 200. The first fluid sensor 4 detects the actual value of a fluid parameter of the second adjustable hydraulic pump system 200, and transmits the actual value of the fluid parameter to an electronic control unit 3′. The electronic control unit 3′ includes computer-based modeling of the dynamics of the second adjustable hydraulic pump system 200, and actuates the first electromagnetically actuated valve 5 based on the actual value of the fluid parameter and the computer-based modeling.

[0074] The control outlet A of the valve device 2 is connected to the first recirculation valve device 17, so that the valve device 2 actuates the first recirculation valve device 17. Through the first recirculation device 17, the fluid flow supplied by the fixed displacement pump 16 is divided as required between the fluid outlet F and a return R of the first recirculation valve device 17.

[0075] The artificial neural network of the electronic control unit 3′ is fed with training data such as the output pressure of the second adjustable hydraulic pump system 200 and a current flow of the first electromagnetically actuated valve 5 in a similar manner to the artificial neural network of the electronic control unit 3. If the valve device 2 comprises the second electromagnetically actuated valve 12, the training data also includes an energization of the second electromagnetically actuated valve 12. The artificial neural network of the electronic control unit 3′ processes the measurement signals of the first fluid sensor 4 and, if applicable, the second fluid sensor 13 in combination with its training data to calculate a prediction of the output pressure of the second adjustable hydraulic pump system 200. Thus, the electronic control unit 3′ implements an adaptive, robust control for the second adjustable hydraulic pump system 200.

[0076] In contrast to the electrohydraulic control device 1 according to the first embodiment, the electrohydraulic control device 1′ according to the second embodiment does not comprise the actuating angle sensor 15.

[0077] With reference to FIGS. 10a and 10b, an electrohydraulic control device 1″ according to a third embodiment is now described. FIG. 10a shows a third adjustable hydraulic pump system 300 comprising the fixed displacement pump 16 and the electrohydraulic control device 1″ according to the third embodiment.

[0078] The electrohydraulic control device 1″ according to the third embodiment comprises a valve device 2″, an electronic control unit 3″ and the first fluid sensor 4. The valve device 2″ comprises the pressure inlet P, the tank outlet T and a first electromagnetically actuated valve 5″. The pressure inlet P of the valve device 2″ is pressurized with an output pressure of the third adjustable hydraulic pump system 300. The first fluid sensor 4 detects the actual value of a fluid parameter of the third adjustable hydraulic pump system 300 and transmits the actual value of the fluid parameter to an electronic control unit 3″. The electronic control unit 3″ includes computer-based modeling of the dynamics of the third adjustable hydraulic pump system 300, and actuates the first electromagnetically actuated valve 5″ based on the actual value of the fluid parameter and the computer-based modeling.

[0079] The third adjustable hydraulic pump system 300 further comprises a second recirculating valve device 18. As shown in FIG. 10a, the second recirculating valve device 18 is the valve device 2″ of the electrohydraulic control device 1″ according to the third embodiment.

[0080] The first electromagnetically actuated valve 5″ is a 2/2 proportional seat valve (see FIG. 10a). As shown in FIG. 10b, the first electromagnetically actuated valve 5″ is alternatively a 2/2 switching seat valve, which is correspondingly actuated by the electronic control 3″ in the form of a digital hydraulic control, so that the first electromagnetically actuated valve 5″ has quasi-proportional dynamics. It is obvious to the skilled person that the first electromagnetically actuated valve 5″ can also be a proportional or switching directional control valve, such as the first electromagnetically actuated valve 5 shown in FIGS. 3a and 3b.

REFERENCE LIST

[0081] 1, 1′, 1″ electrohydraulic control device [0082] 2, 2″ valve device [0083] 3, 3′, 3″ electronic control unit [0084] 4 first fluid sensor [0085] 5, 5″ first electromagnetically actuated valve [0086] 8 variable displacement pump [0087] 9 control piston [0088] 10 first hydraulic connection/inlet [0089] 11 second hydraulic connection/outlet [0090] 12 second electromagnetically actuated valve [0091] 13 second fluid sensor [0092] 14 hydraulic resistor [0093] 15 position angle sensor [0094] 16 constant displacement pump [0095] 17 first recirculation valve device [0096] 18 second recirculation valve device [0097] 100 first adjustable hydraulic pump system [0098] 200 second adjustable hydraulic pump system [0099] 300 third adjustable hydraulic pump system [0100] A control output [0101] P pressure inlet [0102] R return [0103] T tank outlet [0104] F fluid outlet