阅读说明：本技术 工程机械的电子液压式控制装置及方法 (Electronic hydraulic control device and method for construction machinery ) 是由 金泰润 张启凤 于 2019-02-22 设计创作，主要内容包括：本发明的工程机械的电子液压式控制装置包括：控制阀,其设置于液压泵与驱动器之间的液压管线,用于根据具备于内部的阀芯的位移量来控制所述驱动器的动作；阀芯位移调整阀,其用于向所述控制阀的阀芯输出与所输入的压力指令信号成比例的二次压力来控制所述控制阀的阀芯的位移量；压力传感器,其用于检测从所述阀芯位移调整阀输出的二次压力；以及控制部,其根据工程机械的操作信号向所述阀芯位移调整阀输出所述压力指令信号,并在检测到的所述二次压力与通过所述压力指令信号预先设定的设计压力之间的压力差超出已设定的容许范围时校正所述压力指令信号。(The present invention provides an electronic hydraulic control device for construction machinery, comprising: a control valve provided in a hydraulic line between a hydraulic pump and an actuator, for controlling an operation of the actuator in accordance with a displacement amount of a valve element provided inside; a valve element displacement regulating valve for controlling the displacement amount of the valve element of the control valve by outputting a secondary pressure proportional to the input pressure command signal to the valve element of the control valve; a pressure sensor for detecting a secondary pressure output from the spool displacement adjustment valve; and a control unit that outputs the pressure command signal to the valve body displacement adjustment valve in accordance with an operation signal of the construction machine, and corrects the pressure command signal when a pressure difference between the detected secondary pressure and a design pressure preset by the pressure command signal exceeds a preset allowable range.)

1. An electronic hydraulic control device for construction machinery, comprising:

a control valve provided in a hydraulic line between a hydraulic pump and an actuator, for controlling an operation of the actuator in accordance with a displacement amount of a valve element provided inside;

a valve element displacement regulating valve for controlling the displacement amount of the valve element of the control valve by outputting a secondary pressure proportional to the input pressure command signal to the valve element of the control valve;

a pressure sensor for detecting a secondary pressure output from the spool displacement adjustment valve; and

and a control unit that outputs the pressure command signal to the valve body displacement adjustment valve in accordance with an operation signal of the construction machine, and corrects the pressure command signal when a pressure difference between the detected secondary pressure and a design pressure preset by the pressure command signal exceeds a preset allowable range.

2. The electrohydraulic control device of construction machinery according to claim 1,

when the pressure difference exceeds a preset allowable range, the control unit corrects the pressure command signal using a characteristic function of the pressure command signal of the valve body displacement adjustment valve with respect to a design pressure.

3. The electrohydraulic control device of construction machinery according to claim 2,

the control portion reflects a difference value of the pressure command signal converting the detected secondary pressure into the design pressure based on the characteristic function and calculates a correction value of the pressure command signal.

4. The electrohydraulic control device of construction machinery according to claim 2,

the control unit outputs a correction value of the pressure command signal to the valve body displacement adjustment valve as a new pressure command signal.

5. The electrohydraulic control device of construction machinery according to claim 4,

the control portion detects a new secondary pressure output from the spool displacement adjustment valve based on a correction value of the pressure command signal, and corrects the calculated correction value of the pressure command signal using the characteristic function when a pressure difference between the new secondary pressure and the design pressure exceeds a set allowable range.

6. The electrohydraulic control device of construction machinery according to claim 1,

the control section includes:

a storage unit that stores data on a characteristic function of a pressure command signal of the valve body displacement adjustment valve with respect to a design pressure;

a comparison unit that compares the detected secondary pressure with the design pressure and corrects the pressure command signal using the characteristic function data; and

and an output unit that outputs a correction value of the pressure command signal to the valve body displacement adjustment valve as a new pressure command signal.

7. The electrohydraulic control device of construction machinery according to claim 6,

the storage unit stores a correction value of the pressure command signal as a new pressure command signal for the design pressure.

8. The electrohydraulic control device of construction machinery according to claim 1,

the spool displacement adjustment valve includes an electronic proportional pressure reducing valve.

9. An electro-hydraulic control method of a construction machine, the construction machine including an electro-hydraulic system, the electro-hydraulic system comprising: a control valve provided in a hydraulic line between a hydraulic pump and an actuator, for controlling an operation of the actuator in accordance with a displacement amount of a valve element provided inside; and a spool displacement adjustment valve configured to control a displacement amount of the spool of the control valve by outputting a secondary pressure proportional to an input pressure command signal to the spool of the control valve, the electro-hydraulic control method for an engineering machine comprising:

detecting a secondary pressure output from the spool displacement adjustment valve;

correcting the pressure command signal when a pressure difference between the detected secondary pressure and a design pressure preset by the pressure command signal exceeds a set allowable range; and

storing the correction value of the pressure command signal as a new pressure command signal for the design pressure.

10. The electrohydraulic control method of a construction machine according to claim 9,

the step of correcting the pressure command signal includes:

the characteristic function of the pressure command signal of the valve element displacement regulating valve relative to the design pressure is used.

11. The electrohydraulic control method of a construction machine according to claim 10,

the step of correcting the pressure command signal includes:

reflecting a difference value of the pressure command signal converting the detected secondary pressure into the design pressure based on the characteristic function and calculating a correction value of the pressure command signal.

12. The electrohydraulic control method of a construction machine according to claim 10, further comprising:

detecting a new secondary pressure output from the spool displacement adjustment valve based on the calculated correction value of the pressure command signal; and

and correcting the calculated correction value of the pressure command signal by using the characteristic function when the pressure difference between the new secondary pressure and the design pressure exceeds the set allowable range.

13. The electrohydraulic control method of a construction machine according to claim 9, further comprising:

and outputting the correction value of the pressure command signal to the valve element displacement adjustment valve as a new pressure command signal.

Technical Field

The invention relates to an electronic hydraulic control device and method for engineering machinery. More specifically, the present invention relates to an electronic control device and method for a construction machine having an electrohydraulic main control valve using an electronic proportional pressure reducing valve.

Background

An electrohydraulic main control valve that is electronically controlled by an Electronic Proportional Pressure Reducing Valve (EPPRV) may be used in a construction machine. Therefore, compared to a conventional hydraulic main control valve, the electronic proportional pressure reducing valve has a greater risk of failure, and a countermeasure against failure is more important.

As the usage period of the electro proportional pressure reducing valve passes, the secondary pressure of the electro proportional pressure reducing valve may be generated smaller or larger than the pressure command signal. In this case, there is a problem that the pump pressure shows an operating pressure different from a design specification, thereby degrading the performance of the construction machine.

Disclosure of Invention

Technical problem

An object of the present invention is to provide an electrohydraulic control device for a construction machine, which can maintain reliable performance.

Another object of the present invention is to provide an electrohydraulic control method for a construction machine using the control device.

Technical scheme

An electrohydraulic control device for a construction machine according to some exemplary embodiments for achieving the above object of the present invention includes: a control valve provided in a hydraulic line between a hydraulic pump and an actuator, for controlling an operation of the actuator in accordance with a displacement amount of a valve element provided inside; a valve element displacement regulating valve for controlling the displacement amount of the valve element of the control valve by outputting a secondary pressure proportional to the input pressure command signal to the valve element of the control valve; a pressure sensor for detecting a secondary pressure output from the spool displacement adjustment valve; and a control unit that outputs the pressure command signal to the valve body displacement adjustment valve in accordance with an operation signal of the construction machine, and corrects the pressure command signal when a pressure difference between the detected secondary pressure and a design pressure preset by the pressure command signal exceeds a preset allowable range.

In some exemplary embodiments, the control portion may correct the pressure command signal of the spool displacement adjustment valve using a characteristic function of the pressure command signal with respect to a design pressure when the pressure difference exceeds a set allowable range.

In some exemplary embodiments, the control portion may reflect a difference value of the pressure command signal converting the detected secondary pressure into the design pressure and calculate a correction value of the pressure command signal based on the characteristic function.

In some example embodiments, the control portion may output the correction value of the pressure command signal to the spool displacement adjustment valve as a new pressure command signal.

In some exemplary embodiments, the control portion may detect a new secondary pressure output from the spool displacement adjustment valve based on a correction value of the pressure command signal, and when a pressure difference between the new secondary pressure and the design pressure exceeds a set allowable range, the control portion may correct the calculated correction value of the pressure command signal using the characteristic function.

In some exemplary embodiments, the control part may include: a storage unit that stores data on a characteristic function of a pressure command signal of the valve body displacement adjustment valve with respect to a design pressure; a comparison unit that compares the detected secondary pressure with the design pressure and corrects the pressure command signal using the characteristic function data; and an output unit that outputs a correction value of the pressure command signal to the valve body displacement adjustment valve as a new pressure command signal.

In some exemplary embodiments, the storage section may store the correction value of the pressure command signal as a new pressure command signal for the design pressure.

In some exemplary embodiments, the spool displacement adjustment Valve may include an Electronic Proportional Pressure Reducing Valve (EPPRV).

In another aspect, the present invention also discloses an electrohydraulic control method for a construction machine according to some exemplary embodiments for achieving another object of the present invention. The construction machine includes an electro-hydraulic system, the electro-hydraulic system including: a control valve provided in a hydraulic line between a hydraulic pump and an actuator, for controlling an operation of the actuator in accordance with a displacement amount of a valve element provided inside; and a spool displacement adjustment valve for controlling a displacement amount of the spool of the control valve by outputting a secondary pressure proportional to the input pressure command signal to the spool of the control valve, the electro-hydraulic control method for an engineering machine comprising: detecting a secondary pressure output from the spool displacement adjustment valve; correcting the pressure command signal when a pressure difference between the detected secondary pressure and a design pressure preset by the pressure command signal exceeds a set allowable range; and storing the correction value of the pressure command signal as a new pressure command signal for the design pressure.

In some exemplary embodiments, the step of correcting the pressure command signal may include: the characteristic function of the pressure command signal of the valve element displacement regulating valve relative to the design pressure is used.

In some exemplary embodiments, the step of correcting the pressure command signal may include: reflecting a difference value of the pressure command signal converting the detected secondary pressure into the design pressure based on the characteristic function and calculating a correction value of the pressure command signal.

In some exemplary embodiments, the method may further include: detecting a new secondary pressure output from the spool displacement adjustment valve based on the calculated correction value of the pressure command signal; and correcting the calculated correction value of the pressure command signal using the characteristic function when the pressure difference between the new secondary pressure and the design pressure exceeds the set allowable range.

In some exemplary embodiments, the method may further include: and outputting the correction value of the pressure command signal to the valve element displacement adjustment valve as a new pressure command signal.

ADVANTAGEOUS EFFECTS OF INVENTION

According to some exemplary embodiments, in an electro-hydraulic control apparatus and method of a construction machine, a pressure command signal may be corrected when a pressure difference between a secondary pressure (pilot signal pressure) output from a spool displacement adjustment valve according to the pressure command signal and a design pressure preset by the pressure command signal exceeds a set allowable range.

Accordingly, even if the secondary pressure output by the spool displacement adjustment valve changes with the passage of the use period, it is possible to continue to maintain the reliable performance of the construction machine by running the program that corrects the secondary pressure.

However, the effects of the present invention are not limited to the above-mentioned effects, but can be variously expanded within a scope not departing from the idea and field of the present invention.

Drawings

Fig. 1 is a hydraulic circuit diagram showing an electrohydraulic control system of a construction machine according to some exemplary embodiments.

Fig. 2 is a block diagram showing a control section of the electrohydraulic control system of fig. 1.

Fig. 3 is a graph showing a correction process of the pressure command signal executed by the control portion of fig. 1.

Fig. 4 is a sequence diagram illustrating an electro-hydraulic control method of a working machine according to some exemplary embodiments.

Detailed Description

Preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

In the drawings of the present invention, the size of the structure is shown enlarged from the actual size for clarity of the present invention.

In the present invention, the terms first, second, etc. may be used to describe various components, but these components should not be limited to these terms. These terms are used only for the purpose of distinguishing one constituent element from another constituent element.

The terminology used in the description of the invention herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Unless the context clearly dictates otherwise, singular references include plural references. In the present application, terms such as "including" or "having" should be interpreted as specifying the presence of the features, numbers, steps, actions, components, or combinations thereof described in the specification, but not preclude the presence or addition of one or more other features or numbers, steps, actions, components, or combinations thereof.

The specific structural and functional descriptions of the embodiments of the present invention disclosed herein are merely exemplary for the purpose of illustrating the embodiments of the present invention, and the embodiments of the present invention may be embodied in various forms and should not be construed as being limited to the embodiments described herein.

That is, the present invention may be modified in various ways and may have various forms, and specific embodiments thereof will be described in detail herein with reference to the accompanying drawings. However, it is not intended to limit the present invention to the specific forms disclosed, but rather, the present invention is to be construed as including all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention.

Fig. 1 is a hydraulic circuit diagram showing an electrohydraulic control system of a construction machine according to some exemplary embodiments. Fig. 2 is a block diagram showing a control section of the electrohydraulic control system of fig. 1.

Referring to fig. 1 and 2, an electro-hydraulic control system of a construction machine may include: a hydraulic pump 100; a pilot pump 110; at least one control valve 300 provided in the hydraulic line 200 between the hydraulic pump 100 and the at least one actuator 10 and controlling the operation of the actuator 10; at least one spool displacement adjustment valve 400 that outputs pilot working oil from the pilot pump 110 to a spool of the control valve 300 so as to have a secondary pressure proportional to the input pressure command signal; a pressure sensor 410 for detecting the secondary pressure output from the valve core displacement adjustment valve 400; and a control unit 500 that outputs the pressure command signal to the valve body displacement adjustment valve 400 according to an operation signal of the construction machine, and controls the operation of the actuator 10.

In some exemplary embodiments, the work machine may include an excavator, a wheel loader, a forklift, and the like. Next, a case where the construction machine is an excavator will be described. However, it will be appreciated that the control system of some exemplary embodiments is not limited to use with excavators, and may be adapted for use with wheel loaders, forklifts, etc., substantially the same.

The construction machine may include a lower traveling structure, an upper swing structure swingably mounted on the lower traveling structure, and a cab and a front work device provided in the upper swing structure. The front work implement may include a boom, an arm, and a bucket. A boom cylinder for controlling an operation of the boom may be provided between the boom and the upper frame. An arm cylinder for controlling an operation of the arm may be provided between the boom and the arm. Further, a bucket cylinder for controlling an operation of the bucket may be provided between the arm and the bucket. As the boom cylinder, the arm cylinder, and the bucket cylinder extend or contract, the boom, the arm, and the bucket can perform various operations, and the front working device can perform a plurality of operations.

In some exemplary embodiments, the hydraulic pump 100 may be coupled to an engine (not shown) via a power transmission device. Power from the engine may be transferred to the hydraulic pump 100. The working oil discharged from the hydraulic pump 100 may be supplied to the driver 10 through the pump 300.

The control valve 300 may be connected to the hydraulic pump 100 through a hydraulic line 200. When the control valve 300 is switched, the working oil discharged from the hydraulic pump 100 may be supplied to the driver 10 through the control valve 300.

For example, the actuator 10 may be the bucket cylinder and the control valve 300 may be a bucket control valve. In contrast, the actuator may be the boom cylinder or the arm cylinder, and the control valve may be a boom control valve or an arm control valve.

The control valve 300, i.e. the bucket control valve, may be connected to the actuator 10, i.e. the bucket head chamber 12 and the bucket rod chamber 14 of the bucket cylinder, via the bucket head hydraulic line 212 and the bucket rod hydraulic line 214, respectively. Accordingly, the hydraulic oil discharged from the hydraulic pump 100 by switching the control valve 300 can be selectively supplied to the bucket head chamber 12 and the bucket rod chamber 14.

The working oil that drives the bucket cylinder 10 may be returned to the drain tank T through the return hydraulic line. For example, during a bucket excavation operation, the hydraulic oil from the bucket rod chamber 14 may be discharged to the drain tank T through the bucket rod hydraulic line 214 via the control valve 300, i.e., the bucket control valve.

The pilot pump 110 may be connected to the engine, and power from the engine may be transmitted to the pilot pump 110. The pilot pump 110 may discharge the pilot working oil through the pilot flow path 210, and the discharged pilot working oil may be supplied to the spool displacement adjustment valve 400. For example, the pilot pump 110 may include a gear pump.

The pilot working oil discharged from the pilot pump 110 may be supplied to the spool of the control valve 300 through the spool displacement adjustment valve 400. The pilot hydraulic oil discharged from the pilot pump 110 may be supplied to the spool displacement adjustment valve 400 through the pilot flow path 210. The spool displacement adjustment valve 400 may supply pilot signal pressure for controlling the displacement amount of the spool of the control valve 300 in proportion to the input control signal pressure command signal to the spool of the control valve 300.

For example, the pair of valve body displacement adjustment valves 400 may be provided on both sides of the valve body of the control valve 300. The pilot signal pressure output from the spool displacement adjustment valve 400 can be selectively supplied to both sides of the spool in the control valve 300, whereby the control valve 300 can be switched. The spool displacement adjustment valve 400 can supply a pilot signal having a secondary pressure (pilot signal pressure) having a magnitude proportional to the input control signal pressure command signal. The movement of the spool within the control valve 300 may be controlled by the pilot signal pressure. That is, the movement direction of the valve body may be determined according to the supply direction of the pilot signal pressure, and the displacement amount of the valve body may be determined according to the intensity of the pilot signal pressure.

In some exemplary embodiments, the electrohydraulic Control system of the construction machine may include an electrohydraulic Main Control Valve (Main Control Valve) as an assembly having at least one of the Control valves. The valve spool displacement adjustment valve 400 may include an Electronic Proportional Pressure Reducing Valve (EPPRV). The spool displacement adjustment valve 400 can control the pressure (secondary pressure) of the pilot working oil applied to the spool in the control valve according to the inputted electric signal pressure command signal.

In some exemplary embodiments, the control portion 500 may receive an operation signal proportional to an operation amount of an operator from the operation portion 600 and output a pressure command signal as the control signal to the spool displacement adjustment valve 400 in a manner corresponding to the operation signal. The electronic proportional pressure reducing valve may control the valve spool with an electric control signal by outputting a secondary pressure proportional to the pressure command signal to the corresponding valve spool.

Specifically, the control portion 500 may receive an operation signal to the actuator 10, for example, a lever displacement amount, and generate and apply to the spool displacement adjustment valve a control signal corresponding to the received lever displacement amount, for example, a pressure command current signal (mA). The spool displacement adjustment valve may move the spool of the control valve 300 based on the intensity of the applied pilot signal pressure by supplying the pilot signal pressure proportional to the intensity of the applied current (mA) to the spool of the control valve 300. Thus, the received control lever displacement amount for the actuator 10 can be converted into the spool displacement amount of the control valve 300 in the set conversion ratio.

For example, the operation portion 600 may include a lever, a pedal, and the like. When the operator operates the operation section 600, an operation signal corresponding to the operation may be generated. The operating part 600 may include a sensor that measures the displacement amount (or angle) of the lever. The operating part 600 may output a signal such as a voltage signal or a current signal corresponding to the measured amount of displacement. The control part 500 may receive the operation signal and control the main control valve to activate the driver in a manner corresponding to the operation signal.

In some exemplary embodiments, when the secondary pressure detected by the pressure sensor 410 exceeds the allowable range of the design pressure set in advance by the pressure command signal, the control portion 500 may correct the pressure command signal and output the corrected pressure command signal to the spool displacement adjustment valve 400.

The spool displacement adjustment valve 400 may supply the pilot signal pressure (secondary pressure) to the spool of the control valve 300 in proportion to the intensity of the pressure command signal (mA) applied by the control portion 500. The pressure command signal and the secondary pressure may be parameters determined by an inherent characteristic function of the pressure command signal of the spool displacement adjustment valve 400 with respect to the design pressure.

As the period of use elapses, the secondary pressure (pilot signal pressure) output from the spool displacement adjustment valve 400 varies, and therefore, the secondary pressure may exceed an error range of the desired required pressure design pressure. In this case, the control portion 500 may cause the spool displacement adjustment valve 400 to output the secondary pressure that falls within the error range of the desired required pressure by running a correction program that corrects the pressure command signal input to the spool displacement adjustment valve 400.

In some exemplary embodiments, the electrohydraulic control system of the construction machine may further include a selection portion 700 for determining whether the correction routine of the spool displacement adjustment valve 400 is executed or not. The operator may determine whether the correction program is operated or not by the selection unit 700, and the control unit 500 may execute the correction program of the spool displacement adjustment valve 400 according to an operation control signal of the correction program from the selection unit 700.

As illustrated in fig. 2, the control part 500 may include a data receiving part 510, a storage part 520, a comparing part 530, and an output part 540.

The data receiving portion 510 may receive the lever displacement amount from the operation portion 600, and receive the operation control signal of the correction program from the selection portion 700, and receive the secondary pressure output by the spool displacement adjustment valve 400 from the pressure sensor 410. The data receiving unit 510 can receive a lever displacement amount as an operation signal for the boom, arm, bucket, and swing. For example, the data receiving part 510 may receive a bucket lever displacement amount as an operation signal to the bucket cylinder.

The storage portion 520 may store data of a characteristic function of the pressure command signal of the spool displacement adjustment valve 400 with respect to the design pressure. For example, initial data of the characteristic function of the spool displacement adjustment valve 400 may be stored in the storage section 520. Table 1 below shows the parameters of the spool displacement adjustment valve (design pressure with respect to the pressure command signal) stored when the initialization is performed.

[ Table 1]

Pressure command signal reference value (mA)	Secondary pressure reference value (bar)
		…	…
337mA	7bar
		445mA	14bar
596mA	24bar
		…	…
…	…

Further, as will be described later, the storage section 520 may store the correction value of the pressure command signal calculated by the comparison section 530 as a new pressure command signal reference value for the design pressure (secondary pressure) reference value.

The comparing part 530 may compare the detected secondary pressure with a design pressure preset by the pressure command signal and correct the pressure command signal using the characteristic function data. The comparison section 530 may correct the pressure command signal of the spool displacement adjustment valve 400 using a characteristic function of the pressure command signal with respect to the design pressure.

For example, a characteristic function over a section between the design pressure and the detected secondary pressure may be decided, and a correction value of the pressure command signal may be calculated based on a difference of the pressure command signal that converts the detected secondary pressure into the design pressure reflected by the characteristic function over the section.

Further, it is possible to detect a new secondary pressure output by the spool displacement adjustment valve 400 based on the correction value of the pressure command signal, and correct the calculated correction value of the pressure command signal using the characteristic function when the pressure difference between the new secondary pressure and the design pressure exceeds the set allowable range.

The output portion 540 may output the correction value of the pressure command signal to the spool displacement adjustment valve 400 as a new pressure command signal.

The following describes a correction process of the pressure command signal executed based on the correction program.

Fig. 3 is a graph showing a correction process of the pressure command signal executed by the control portion of fig. 1.

Table 2 below shows the correction of the pressure command signal for a design pressure of 14 bar.

[ Table 2]

Referring to fig. 3 and table 2, when receiving the operation control signal of the correction program, the control part 500 may output the first pressure command signal C0(445mA) stored as the initialization execution value to the spool displacement adjustment valve 400. Next, the secondary pressure P0(15.5bar) output from the spool displacement adjustment valve 400 is compared by the pressure sensor 410 with the design pressure (14bar) preset by the initial pressure command signal C0, and when the pressure difference exceeds the set allowable range, the correction value C1 of the pressure command signal can be calculated using the characteristic function.

The correction value of the pressure command signal may be calculated based on the characteristic function reflecting the difference of the pressure command signal that converts the detected secondary pressure P0 into the design pressure (14 bar). The characteristic function F over the interval between 14bar and 24bar may be determined from the data of the characteristic function of the spool displacement adjustment valve 400, and the correction value of the pressure command signal may be calculated using linear interpolation in the interval. For example, since the interval F1 between 14bar and 24bar has a conversion ratio of 15.1mA (596-.

Next, the secondary pressure P1(13.2bar) output from the spool displacement adjustment valve 400 may be compared with the design pressure (14bar) preset by the primary pressure command signal C0 based on the correction value C1 of the pressure command signal, and when the pressure difference exceeds the set allowable range R, the corrected correction value C2 of the pressure command signal may be calculated using the characteristic function.

It is possible to reflect the difference of the pressure command signal converting the detected secondary pressure P1 into the design pressure 14bar based on the characteristic function and calculate the correction value of the pressure command signal. The characteristic function F2 over the interval between 7bar and 14bar may be determined from the data of the characteristic function of the spool displacement adjustment valve 400, and the correction value of the pressure command signal may be calculated using linear interpolation in the interval. For example, since there is a conversion ratio of 15.4mA ((445-) 337)/7mA/bar) per 1bar in the interval between 7bar and 14bar, a new pressure command signal value (457.32mA (445mA- (0.8bar 15.4mA/bar)) can be calculated reflecting the difference (0.8bar 15.4mA/bar) of the pressure command signal converting the detected secondary pressure to the design pressure.

Next, the secondary pressure p214.2bar output from the spool displacement adjustment valve 400 may be compared with the design pressure 14bar preset by the initial pressure command signal C0 based on the correction value C2 of the pressure command signal, and when the pressure difference is within the set allowable range R (e.g., 1bar), the correction process may be ended. At this time, the correction value C2 of the pressure command signal calculated by the comparison section 530 may be stored as a new pressure command signal reference value for the corresponding design pressure (14bar), and the output section 540 may output the correction value C2 of the pressure command signal newly stored as the pressure command signal for the corresponding design pressure (14bar) to the spool displacement adjustment valve 400.

Further, the control part 500 may perform a correction process of the pressure command signal for another sampled design pressure. When the pressure difference is not within the set allowable range even after the correction is performed more than the set number of times, the control portion 500 may perform initialization, output the first pressure command signal stored as the initialization execution value to the spool displacement adjustment valve 400, and correct the pressure command signal using the adjusted characteristic function of the spool displacement adjustment valve.

As described above, the electrohydraulic control device of the construction machine can correct the pressure command signal when the pressure difference between the secondary pressure output from the valve body displacement adjustment valve and the design pressure preset by the pressure command signal exceeds the preset allowable range.

Thus, even if the secondary pressure (pilot signal pressure) output by the EPPR valve changes as the period of use passes, it is possible to continue to maintain constant performance of the work machine by running a program that corrects the secondary pressure.

A method of controlling a construction machine using the electrohydraulic control device of fig. 1 and 2 will be described.

Fig. 4 is a sequence diagram illustrating an electrohydraulic control method for a construction machine according to some exemplary embodiments.

Referring to fig. 1, 2 and 4, it is possible to receive the secondary pressure output from the spool displacement adjustment valve 400 by the pressure sensor 410 based on the operation control signal of the correction program of the spool displacement adjustment valve 400, compare the detected secondary pressure with the design pressure (S100), and determine whether the pressure difference between the detected secondary pressure and the design pressure exceeds the set allowable range (S110).

In some exemplary embodiments, the operator may determine whether the correction program is executed or not by setting a correction program selection button from a menu through the selection part 700, for example, an instrument panel.

When receiving the operation control signal of the correction program from the selection part 700, the control part 500 may output an initial pressure command signal for the sampled design pressure (for example, 14bar) to the spool displacement adjustment valve 400, and the spool displacement adjustment valve 400 may output a secondary pressure (pilot signal pressure) based on the input pressure command signal. In this case, the bucket 10 of the construction machine can be controlled to be in a posture in which it is in contact with the ground.

Next, the secondary pressure output from the valve core displacement adjustment valve 400 and the sampled design pressure may be compared by the pressure sensor 410, and it may be determined whether the pressure difference is within the set allowable range.

Next, when the pressure difference exceeds the set allowable range, a correction value of the pressure command signal may be calculated (S120).

In some exemplary embodiments, the control portion 500 may correct the pressure command signal of the spool displacement adjustment valve 400 using a characteristic function of the pressure command signal with respect to the design pressure. It is possible to reflect the difference of the pressure command signal converting the detected secondary pressure into the design pressure based on the characteristic function and calculate the correction value of the pressure command signal.

For example, a characteristic function in a section between the design pressure and the detected secondary pressure may be determined, and a new pressure command signal value in the section in which the detected secondary pressure is converted into the design pressure using linear interpolation may be determined as a correction value of the pressure command signal.

Thereafter, it may be judged whether or not the secondary pressure output from the valve core displacement adjustment valve 400 is within the set allowable range based on the correction value of the pressure command signal (S130).

When the secondary pressure is within the set allowable range, the correction process may be ended. At this time, the correction value of the pressure command signal may be stored as a new pressure command signal reference value for the corresponding design pressure, and the control portion 500 may output the correction value of the pressure command signal newly stored as the pressure command signal for the corresponding design pressure to the spool displacement adjustment valve 400.

When the secondary pressure exceeds the set allowable range, it may be judged whether the initialization is performed (S140).

When the correction based on the correction program is less than the set number of times, the control part 500 may perform step S120 to calculate the correction value of the pressure command signal.

When the pressure difference is not within the set allowable range even after the correction based on the correction program is performed more than the set number of times, the initialization may be performed (S150).

The control unit 500 may output a first pressure command signal stored as an initialization execution value to the spool displacement adjustment valve 400, and perform step S120 to correct the first pressure command signal using the adjusted characteristic function of the spool displacement adjustment valve.

Although the foregoing has been described with reference to the embodiments of the present invention, it will be understood by those skilled in the art that the present invention may be variously modified and changed within the scope and spirit of the present invention as set forth in the following claims.

Reference numerals

10: driver, 12: head chamber, 14: rod chamber, 100: hydraulic pump, 110: pilot pump, 200: hydraulic line, 210: pilot flow path, 212: head hydraulic line, 214: rod hydraulic line, 300: control valve, 400: valve body displacement adjustment valve, 500: control unit, 510: data reception unit, 520: storage section, 530: comparison unit, 540: output unit, 600: operation unit, 700: a selection unit.