Control method, control device and hydraulic system for hydraulic system

Abstract

The present application relates to the technical field of hydraulic systems, and in particular to a control method, a control device and a hydraulic system for hydraulic systems. The method comprises: obtaining the load pressure of the actuator and the adjustment factor for the LS valve, wherein the adjustment factor comprises at least one of the oil temperature, the output pressure of the pump, the flow difference corresponding to the actuator and the speed of the prime mover; determining the preset pressure difference threshold value according to the adjustment factor and the preset relationship, wherein the oil temperature, the output pressure and the flow difference are all positively correlated with the preset pressure difference threshold value, and the speed is negatively correlated with the preset pressure difference threshold value; determining the control pressure according to the load pressure and the preset pressure difference threshold value; generating a control signal for the LS valve based on the control pressure, wherein the control signal is used to adjust the output pressure of the pump to the control pressure, thereby realizing a fast match between the pump and the valve, reducing the response time, improving the control accuracy of the pump, and improving the intelligence of the hydraulic system.

Description

Technical Field

[0001] The present application relates to the technical field of hydraulic systems, and in particular to a control method, a control device, a hydraulic system and a storage medium for a hydraulic system. Background Art

[0002] The existing hydraulic system pump-valve matching generally adopts a load-sensitive system, which transmits the maximum load pressure to the control end of the load-sensitive valve LS in real time by setting a shuttle valve, so as to adjust the pump displacement through the load-sensitive valve, thereby achieving a balance of pump-valve flow. The load-sensitive system generally compares the load pressure of the two cylinders of the boom through a shuttle valve, and transmits the maximum load pressure to the load-sensitive valve of the pump displacement mechanism through the shuttle valve, so as to balance the pump outlet pressure with the LS pressure by adjusting the displacement of the variable pump. This mechanical-hydraulic feedback method leads to low system stability and easy oscillation. When the system starts quickly, it cannot be adjusted in time, resulting in slow system response and low control accuracy. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide a control method, a control device, a hydraulic system and a storage medium for a hydraulic system, so as to solve the problems of slow response and low control accuracy caused by pure mechanical control of the hydraulic system in the prior art.

[0004] In order to achieve the above-mentioned object, the first aspect of the present application provides a control method for a hydraulic system, the hydraulic system comprising an actuator, a prime mover, an LS valve and a pump, the LS valve being used to adjust the output pressure of the pump, and the control method comprising:

[0005] Obtaining a load pressure of the actuator and a regulating factor for the LS valve, the regulating factor comprising at least one of an oil temperature, an output pressure of a pump, a flow difference corresponding to the actuator, and a rotation speed of the prime mover;

[0006] The preset differential pressure threshold is determined according to the adjustment factor and the preset relationship, wherein the preset relationship records the relationship between the adjustment factor and the preset differential pressure threshold, the oil temperature, the output pressure and the flow difference may all be positively correlated with the preset differential pressure threshold, and the rotation speed may be negatively correlated with the preset differential pressure threshold;

[0007] Determine the control pressure according to the load pressure and the preset pressure difference threshold;

[0008] Based on the control pressure, a control signal is generated for the LS valve, which control signal is used to adjust the output pressure of the pump to the control pressure.

[0009] In an embodiment of the present application, the hydraulic system also includes a valve core connected to the oil inlet of the actuator, and the control method also includes: before obtaining the load pressure of the actuator and the adjustment factor for the LS valve, when receiving a handle command signal, obtaining a first actual displacement of the valve core; determining the pressure difference between the output pressure of the pump and the load pressure; determining the actual flow at the oil inlet of the actuator based on the pressure difference and the first actual displacement; and determining the difference between the flow corresponding to the handle command signal and the actual flow as the flow difference.

[0010] In an embodiment of the present application, generating a control signal for the LS valve based on the control pressure includes: determining a control displacement according to the control pressure and a flow output characteristic of a pump; and generating a control signal according to the control displacement.

[0011] In an embodiment of the present application, determining the control displacement according to the control pressure and the flow output characteristics of the pump includes: determining a first displacement according to the control pressure and the flow output characteristics of the pump; determining a second displacement according to the control pressure and the actual pressure at the outlet of the pump; and determining the control displacement according to the first displacement and the second displacement.

[0012] In an embodiment of the present application, generating a control signal according to a control displacement includes: obtaining an actual displacement of the LS valve; determining a first control signal according to the control displacement; determining a second control signal according to a displacement difference between the control displacement and the actual displacement; and determining a control signal according to the first control signal and the second control signal.

[0013] In an embodiment of the present application, determining the second control signal according to the displacement difference between the control displacement and the actual displacement includes: determining a closed-loop control parameter according to the rotation speed; and determining the second control signal according to the displacement difference and the closed-loop control parameter.

[0014] In an embodiment of the present application, the control method also includes: before determining the preset pressure difference threshold value based on the adjustment factor and the preset relationship, judging whether the flow rate of the pump has reached a saturated state; when the flow rate of the pump has reached a saturated state, determining the preset pressure difference threshold value as a preset pressure difference lower limit value.

[0015] A second aspect of the present application provides a control device for a hydraulic system, comprising:

[0016] a memory configured to store instructions;

[0017] The processor is configured to call instructions from the memory and implement the above-mentioned control method for the hydraulic system when executing the instructions.

[0018] A third aspect of the present application provides a hydraulic system, comprising:

[0019] LS valve, used to adjust the output pressure of the pump;

[0020] Pumps;

[0021] Actuator;

[0022] Prime mover;

[0023] The above-mentioned control device for the hydraulic system.

[0024] A fourth aspect of the present application provides a machine-readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute the above-mentioned control method for a hydraulic system.

[0025] Through the above technical solution, the load pressure of the actuator and the adjustment factor for the LS valve are obtained, and the preset pressure difference threshold is determined according to the adjustment factor and the preset relationship, and the control pressure is determined according to the load pressure and the preset pressure difference threshold; then, a control signal for the LS valve is generated based on the control pressure to adjust the output pressure of the pump to the control pressure, thereby achieving rapid matching between the pump and the valve, reducing the response time, improving the control accuracy of the pump, and improving the intelligence level of the hydraulic system.

[0026] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings:

[0028] Figure 1 A first flow chart of a control method for a hydraulic system according to an embodiment of the present application is schematically shown;

[0029] Figure 2 A schematic diagram of a hydraulic system according to an embodiment of the present application is schematically shown;

[0030] Figure 3 A second flow chart of a control method for a hydraulic system according to an embodiment of the present application is schematically shown;

[0031] Figure 4 A third flow chart of a control method for a hydraulic system according to an embodiment of the present application is schematically shown;

[0032] Figure 5 A schematic diagram schematically shows a control method for a hydraulic system according to an embodiment of the present application;

[0033] Figure 6 Another schematic diagram of a hydraulic system according to an embodiment of the present application is schematically shown;

[0034] Figure 7 The internal structure diagram of a computer device according to an embodiment of the present application is schematically shown.

[0035] Description of Reference Numerals

[0036] 1. Load sensitive pump 2.1. Filter 2.2. Pilot oil pressure reducing valve

[0037] 2.3, First Union pilot solenoid valve 2.4, LS valve core 3.1, pilot solenoid valve

[0038] 3.2、Pilot solenoid valve 3.3、Pilot solenoid valve 3.4、Pilot solenoid valve

[0039] 4.1, main valve core 4.2, main valve core 4.3, main valve core

[0040] 4.4, main valve core 5.1, safety valve 5.2, safety valve

[0041] 6.1. Pressure sensor 6.2. Pressure sensor 6.3. Pressure sensor

[0042] 6.4, pressure sensor 7.1, boom cylinder 8, controller

[0043] 9. Handle DETAILED DESCRIPTION

[0044] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0045] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back...), such directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0046] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0047] Figure 1 The flowchart of a control method for a hydraulic system according to an embodiment of the present application is schematically shown. Figure 1 As shown, an embodiment of the present application provides a control method for a hydraulic system, the hydraulic system includes an actuator, a prime mover, an LS valve and a pump, the LS valve is used to adjust the output pressure of the pump, and the control method may include the following steps.

[0048] Step 101: Obtaining the load pressure of the actuator and the adjustment factor for the LS valve, where the adjustment factor includes at least one of the oil temperature, the output pressure of the pump, the flow difference corresponding to the actuator, and the rotation speed of the prime mover.

[0049] Step 102: Determine a preset pressure difference threshold value based on the adjustment factor and the preset relationship, wherein the preset relationship records the relationship between the adjustment factor and the preset pressure difference threshold value, the oil temperature, output pressure and flow difference may be positively correlated with the preset pressure difference threshold value, and the rotation speed may be negatively correlated with the preset pressure difference threshold value.

[0050] The hydraulic system may include an actuator (such as a cylinder, a hydraulic motor, etc.), a prime mover (such as a motor, an engine, etc.), an LS valve, and a pump. Among them, the LS valve can be used to adjust the output pressure of the pump. The processor can obtain the load pressure of the actuator and the adjustment factor for the LS valve, wherein the adjustment factor includes at least one of the oil temperature, the output pressure of the pump, the flow difference corresponding to the actuator, and the speed of the prime mover. After obtaining the adjustment factor for the LS valve, the processor can determine the preset pressure difference threshold according to the adjustment factor and the preset relationship, wherein the preset relationship records the relationship between the adjustment factor and the preset pressure difference threshold. The oil temperature, the output pressure, and the flow difference can all be positively correlated with the preset pressure difference threshold, and the speed can be negatively correlated with the preset pressure difference threshold. The load pressure can be collected by a pressure sensor arranged on the actuator, the oil temperature can be collected by a temperature sensor arranged on the oil supply pipeline of the hydraulic system or at the oil inlet of the pump, and the output pressure can be collected by a pressure sensor arranged at the inlet or outlet of the pump. The flow difference corresponding to the actuator can be the difference between the command flow and the actual flow of the actuator, wherein the actual flow of the actuator can be collected by a flow sensor arranged at the oil inlet or outlet of the actuator, or calculated based on a small hole flow formula, etc., and the command flow can be determined based on a handle signal or a target flow value input by a user, etc. The speed of the prime mover can be collected by a speed sensor arranged on the prime mover.

[0051] Taking the adjustment factor including oil temperature as an example, the processor can determine whether the oil temperature is in an increasing trend or a decreasing trend based on the oil file collected by the temperature sensor. In the case where the oil temperature is in an increasing trend, based on the positive correlation between the oil temperature and the preset pressure difference threshold, the processor can increase the preset pressure difference threshold.

[0052] Taking the adjustment factor including the speed as an example, the processor can determine whether the speed is in an increasing trend or a decreasing trend according to the speed collected by the speed sensor. When the speed is in an increasing trend, the processor can reduce the preset pressure difference threshold based on the negative correlation between the speed and the preset pressure difference threshold.

[0053] The adjustment factors include output pressure and rotation speed. The processor can determine whether the output pressure and rotation speed are in an increasing trend or a decreasing trend respectively according to the output pressure collected by the pressure sensor and the rotation speed collected by the speed sensor. When the output pressure is in an increasing trend and the rotation speed is in an increasing trend, based on the positive correlation between the output pressure and the preset pressure difference threshold, the processor can increase the preset pressure difference threshold. Based on the negative correlation between the rotation speed and the preset pressure difference threshold, the processor can reduce the preset pressure difference threshold.

[0054] Step 103: Determine the control pressure according to the load pressure and the preset pressure difference threshold.

[0055] Step 104 : Generate a control signal for the LS valve based on the control pressure, the control signal being used to adjust the output pressure of the pump to the control pressure.

[0056] After obtaining the load pressure of the actuator, the processor can determine the control pressure according to the load pressure and the preset relationship threshold. After obtaining the control pressure, the processor can generate a control signal for the LS valve based on the control pressure, and the control signal is used to adjust the output pressure of the pump to the control pressure to improve the response speed between the pump valve and improve the control accuracy of the pump.

[0057] In an embodiment of the present application, the hydraulic system also includes a valve core connected to the oil inlet of the actuator, and the control method also includes: before obtaining the load pressure of the actuator and the adjustment factor for the LS valve, when receiving a handle command signal, obtaining a first actual displacement of the valve core; determining the pressure difference between the output pressure of the pump and the load pressure; determining the actual flow at the oil inlet of the actuator based on the pressure difference and the first actual displacement; and determining the difference between the flow corresponding to the handle command signal and the actual flow as the flow difference.

[0058] The hydraulic system also includes a valve core connected to the oil inlet of the actuator. Before obtaining the load pressure of the actuator and the adjustment factor for the LS valve, the processor can receive a handle command signal. When the handle command signal is received, the processor can obtain the first actual displacement of the valve core. The processor can also determine the pressure difference between the output pressure of the pump and the load pressure, and determine the actual flow at the oil inlet of the actuator based on the pressure difference and the first actual displacement. After determining the actual flow at the oil inlet of the actuator, the processor can determine the difference between the flow corresponding to the handle command signal and the actual flow as the flow difference corresponding to the actuator. The handle command signal can be triggered by the user operating the handle according to actual needs. The first actual displacement of the valve core can be collected by a displacement sensor installed on the valve core. For example, the displacement sensor can be a linear displacement sensor. The displacement sensor can collect the first actual displacement of the valve core in real time, and the processor can receive the first actual displacement from the displacement sensor.

[0059] For example, the user can manipulate the handle according to actual needs, and the handle can generate a handle command signal accordingly, and the handle command signal can be a voltage signal. The processor can receive the handle command signal and determine the flow corresponding to the handle command signal. The processor also obtains the first actual displacement of the valve core connected to the oil inlet of the actuator in the hydraulic system under the handle command signal. After obtaining the first actual displacement of the valve core, the processor can determine the actual flow of the oil inlet of the actuator at this time according to the first actual displacement, the output pressure of the pump and the load pressure difference. Specifically, the processor can determine the pressure difference between the output pressure of the pump and the load pressure. After obtaining the pressure difference between the output pressure of the pump and the load pressure, the processor can determine the actual flow of the oil inlet of the actuator according to the pressure difference and the first actual displacement. After obtaining the actual flow of the oil inlet of the actuator, the processor can determine the difference between the flow corresponding to the handle command signal and the actual flow as the flow difference of the actuator.

[0060] In an embodiment of the present application, generating a control signal for the LS valve based on the control pressure includes: determining a control displacement according to the control pressure and a flow output characteristic of a pump; and generating a control signal according to the control displacement.

[0061] The processor may generate a control signal for the LS valve based on the control pressure. Specifically, the processor may determine the control displacement of the LS valve according to the control pressure of the pump and the flow output characteristics of the pump. After determining the control displacement, the processor may generate a control signal according to the control displacement to act on the LS valve with the control signal so that the output pressure of the pump is adjusted to the control pressure, so as to improve the control accuracy of the pump and accurately adjust the output pressure of the pump to the control pressure. Among them, the flow output characteristics may include the flow output size of the pump, the oil temperature, the pump displacement, etc.

[0062] For example, after generating the control pressure according to the load pressure of the pump and the preset pressure difference threshold, the processor can generate a control signal according to the control pressure of the pump and the flow output characteristics of the pump such as the output flow, oil temperature, and pump displacement, wherein the control signal can be a control current or control end pressure acting on the LS valve. The control current is applied to the LS valve to adjust the output pressure of the pump to the control pressure. For example, the valve core of the LS valve can be moved left and right based on the size of the control current acting on the LS valve to change the inclination angle of the swash plate of the pump, thereby controlling the displacement of the pump so that the output pressure of the pump is consistent with the control pressure, or the error between the output pressure of the pump and the control pressure is within a certain range.

[0063] In an embodiment of the present application, determining the control displacement according to the control pressure and the flow output characteristics of the pump includes: determining a first displacement according to the control pressure and the flow output characteristics of the pump; determining a second displacement according to the control pressure and the actual pressure at the outlet of the pump; and determining the control displacement according to the first displacement and the second displacement.

[0064] The processor may determine the control displacement according to the control pressure and the flow output characteristics of the pump. Specifically, the processor may determine the first displacement of the LS valve according to the control pressure of the pump and the flow output characteristics of the pump. The processor may also determine the second displacement of the LS valve according to the control pressure and the actual pressure at the outlet of the pump. After obtaining the first displacement and the second displacement, the processor may determine the control displacement of the LS valve according to the first displacement and the second displacement to implement closed-loop displacement control of the LS valve.

[0065] For example, the processor may determine a functional relationship between a control pressure of the pump, a flow output characteristic of the pump, and a first displacement of the LS valve, wherein the flow output characteristic of the pump may include an oil temperature T of the oil output by the pump, a control pressure of the pump, and a first displacement of the LS valve. , oil temperature T and the first displacement of the LS valve The functional relationship between them can be The processor can determine the first displacement of the LS valve based on the functional relationship. The processor can also obtain the speed n of the prime mover collected by the speed sensor installed on the prime mover, and determine the control pressure of the pump. , oil temperature T, speed n and the first displacement of the LS valve Functional relationship between , and then the first displacement of the LS valve is calculated based on the functional relationship.

[0066] The processor can also collect the actual pressure at the pump outlet through the pressure sensor installed at the pump outlet. , and determine the actual pressure The control pressure of the pump The pressure difference between , after getting the pressure difference Afterwards, according to the pressure difference Determine the second displacement of the LS valve Specifically, the processor can obtain the engine speed and set the pressure difference according to the speed. The control parameters may include the pressure closed loop proportional term parameter KP and the pressure closed loop integral term parameter KI. And determine the control parameters, pressure difference and the second displacement of the LS valve The functional relationship between After obtaining the first displacement and the second displacement, the processor may determine the sum of the first displacement and the second displacement as the control displacement of the LS valve.

[0067] In an embodiment of the present application, generating a control signal according to a control displacement includes: obtaining an actual displacement of the LS valve; determining a first control signal according to the control displacement; determining a second control signal according to a displacement difference between the control displacement and the actual displacement; and determining a control signal according to the first control signal and the second control signal.

[0068] The processor may generate a control signal based on the control displacement. Specifically, the processor may obtain the actual displacement of the LS valve. The processor may also determine a first control signal based on the control displacement. After obtaining the actual displacement and the control displacement, the processor may determine a second control signal based on the displacement difference between the control displacement and the actual displacement. After obtaining the second control signal, the processor may determine a control signal for the pump based on the first control signal and the second control signal.

[0069] For example, the processor can obtain the actual displacement of the LS valve through a displacement sensor installed at the LS valve. . And determine the actual displacement With control displacement The displacement difference between The processor can determine the control displacement With the first control signal The functional relationship between them is based on the functional relationship and the control displacement Determine the first control signal , the functional relationship can be is the independent variable, the first control signal is a linear function of the dependent variable. The processor can also determine the displacement difference With the second control signal The functional relationship between Determine the second control signal , the functional relationship can be expressed as displacement difference is the independent variable, the second control signal is a linear function of the dependent variable. Finally, the processor can and the second control signal The sum of is determined as the control signal.

[0070] In an embodiment of the present application, determining the second control signal according to the displacement difference between the control displacement and the actual displacement includes: determining a closed-loop control parameter according to the rotation speed; and determining the second control signal according to the displacement difference and the closed-loop control parameter.

[0071] The processor may determine the second control signal according to the displacement difference between the control displacement and the actual displacement. Specifically, the processor may determine the closed-loop control parameter according to the rotation speed. After determining the closed-loop control parameter, the processor may determine the second control signal according to the displacement difference and the closed-loop control parameter.

[0072] For example, since the engine speed is different in different gears, the adjustment speed of the pump needs to be adjusted according to the engine speed. Specifically, the processor can obtain the engine speed in real time based on the speed sensor. And determine the closed-loop control parameters when the pump is closed-loop controlled according to the engine speed, such as the pressure closed-loop proportional item parameter KP, the pressure closed-loop integral item parameter KI, the displacement closed-loop proportional item parameter KP1, the displacement closed-loop integral item parameter KI1, etc. When the values ​​of KP, KI, KP1, and KI1 are too large, it is easy to cause the pressure overshoot at the pump port, thereby causing the engineering machinery where the hydraulic system is located to oscillate. Therefore, the values ​​of KP, KI, KP1, and KI1 can be appropriately reduced when the engine speed is high. Specifically, the processor can obtain the working conditions of the engineering machinery and set the adjustment parameters based on the working conditions. Then adjust the values ​​of the closed-loop control parameters KP, KI, KP1, and KI1 based on the functional relationship between the adjustment parameters and the speed, so that the closed-loop control parameters are stable within a certain range. The processor can determine a second control signal based on the displacement difference and the closed-loop control parameters to control the pump, thereby avoiding the oscillation of the engineering machinery caused by the overshoot of the pump port pressure.

[0073] In an embodiment of the present application, the control method also includes: before determining the preset pressure difference threshold value based on the adjustment factor and the preset relationship, judging whether the flow rate of the pump has reached a saturated state; when the flow rate of the pump has reached a saturated state, determining the preset pressure difference threshold value as a preset pressure difference lower limit value.

[0074] Before determining the preset pressure difference threshold according to the adjustment factor and the preset relationship, the processor can determine whether the flow of the pump has reached a saturated state. When it is determined that the flow of the pump has reached a saturated state, the processor can determine the preset pressure difference threshold to be a preset pressure difference lower limit.

[0075] For example, the processor may determine whether the pressure difference between the pump and the LS valve is within a preset range. If the pressure difference between the pump and the LS valve is within the preset range, the processor may determine that the flow rate of the pump has reached a saturated state. If the flow rate of the pump has reached a saturated state, the processor may determine that the preset pressure difference threshold is a preset pressure difference lower limit value.

[0076] For example, the processor may obtain the total demand flow of each working link in the hydraulic system, and compare the total demand flow with the rated flow of the pump to determine whether the flow of the pump has reached a saturated state. When the total demand flow is greater than the rated flow, the processor may determine that the flow of the pump has reached a saturated state. When the flow of the pump has reached a saturated state, the processor may determine that the preset pressure difference threshold is the preset pressure difference lower limit value.

[0077] In the embodiments of the present application, Figure 2As shown, the hydraulic system includes a load sensitive pump 1, a filter 2.1, a pilot oil pressure reducing valve 2.2, a first-link pilot solenoid valve 2.3, an LS valve core 2.4, a pilot solenoid valve 3.1, a pilot solenoid valve 3.2, a pilot solenoid valve 3.3, a pilot solenoid valve 3.4, a main valve core 4.1, a main valve core 4.2, a main valve core 4.3, a main valve core 4.4, a safety valve 5.1, a safety valve 5.2, a pressure sensor 6.1, a pressure sensor 6.2, a pressure sensor 6.3, a pressure sensor 6.4, a boom cylinder 7.1, a controller 8 and a handle 9.

[0078] The A port of the boom oil cylinder 7.1 is connected to the T pipeline by the main valve core 4.1, and the main valve core 4.2 is connected to the P pipeline. The valve core displacement of the main valve core 4.1 is driven by the pilot solenoid valve 3.1, and the valve core displacement of the main valve core 4.2 is driven by the pilot solenoid valve 3.2. The B port of the boom oil cylinder 7.1 is connected to the T pipeline by the main valve core 4.3, and the main valve core 4.4 is connected to the P pipeline. The valve core displacement of the main valve core 4.3 is driven by the pilot solenoid valve 3.3, and the valve core displacement of the main valve core 4.4 is driven by the pilot solenoid valve 3.4. The pilot solenoid valve 3.1, the pilot solenoid valve 3.2, the pilot solenoid valve 3.3, and the pilot solenoid valve 3.4 are all controlled by the controller 8. The controller 8 can establish different hydraulic circuits based on the switches of the main valve core 4.1, the main valve core 4.2, the main valve core 4.3, and the main valve core 4.4. The controller 8 can also collect the handle instructions of the handle 9 to identify the movement state of the boom. Pressure sensor 6.3 and pressure sensor 6.4 can provide real-time feedback of the load pressure of boom cylinder 7.1. .

[0079] like Figure 3 As shown, the controller 8 can identify the command flow Q, wherein the command flow Q is determined based on the handle command signal, and the handle command signal can be a voltage signal. Based on the hydraulic system requirements, the handle opening can be mapped to the command flow to obtain the command flow Q corresponding to the voltage signal.

[0080] Controller 8 can recognize (Output pressure of load sensing pump), PA1 (Port A pressure of boom cylinder), PB1 (B port pressure of boom cylinder), PT (pressure of the first pilot solenoid valve), T (oil temperature of the hydraulic system), displacement (The displacement of the main valve core corresponds to the actual displacement of the LS valve mentioned above). For example, when the oil is flowing into the A port of the boom cylinder, the displacement recognized by the controller is The controller can determine the output pressure of the load sensing pump PP And the A port pressure of the boom cylinder PA1 The pressure difference between . After getting the pressure difference The controller can then , oil temperature T and displacement Determine the actual flow at the boom cylinder ,Right now = . After getting the actual flow The controller can then calculate the flow difference, which is the command flow Q and actual flow The difference between the two is determined as the flow difference (Corresponding to the flow difference corresponding to the actuator above).

[0081] The controller can determine whether the flow of the load sensing pump has reached saturation, that is, whether the pressure difference between the load sensing pump and the LS valve is within a preset range. When the flow of the load sensing pump reaches saturation, that is, the pressure difference between the load sensing pump and the LS valve is within a preset range, the controller can determine the load sensing margin. (corresponding to the preset differential pressure threshold above) is the minimum value of the load sensitivity margin ,Right now When the flow rate of the load-sensing pump is not saturated, the controller can , Engine speed , oil temperature and the output pressure of the load sensing pump Adaptive adjustment of load sensing margin ， Right now Among them, the flow difference With load sensing margin There is a positive correlation between the engine speed With load sensing margin There is a negative correlation between the oil temperature With load sensing margin There is a positive correlation between the output pressure of the load-sensing pump and With load sensing margin There is a positive correlation between them.

[0082] Specifically, the controller determines the flow difference When the actual flow rate is greater than the preset value, With instruction flow The gap between them is large. To ensure the stable operation of the hydraulic system, the displacement of the load-sensing pump should be adjusted as soon as possible to achieve the command flow. The larger the load sensitivity margin is, the greater the The larger the valve core displacement, the faster the LS pressure changes, and the output pressure of the load-sensitive pump With load sensing pressure The pressure difference between the load sensing pump and the load sensing pump becomes smaller, and the actual flow rate will gradually rise, will gradually decrease; slowly, it can be reduced , so that the output pressure of the load sensing pump With load sensing pressure The pressure difference between the two is reduced, which reduces the pressure loss and the energy consumption of the hydraulic system.

[0083] The controller can also detect the engine speed in real time . Speed The larger the value, the slower the displacement change of the load sensing pump should be. Otherwise, the hydraulic system will oscillate due to over-rapid adjustment. Therefore, the controller needs to reduce To reduce the displacement change speed of the load sensing pump. The smaller the value, the greater the controller needs to increase in order to reduce the flow rise time. To increase the displacement change speed of load sensing pumps.

[0084] The controller can obtain the oil temperature in real time . Oil temperature When the value is higher, the viscosity of the oil is lower and the controller needs to reduce the value appropriately. ; Oil temperature The lower the value, the greater the oil viscosity, and the controller needs to be increased appropriately. .

[0085] The controller can obtain the output pressure of the load-sensing pump in real time . Output pressure When the pressure is higher, the valve core displacement is larger. In order to avoid the hydraulic system oscillation caused by too fast pressure reduction, the displacement change speed should be reduced. At this time, the controller should appropriately reduce ; Output pressure The lower the value, the controller should increase the .

[0086] The controller can be based on the flow difference , Engine speed , oil temperature and the output pressure of the load sensing pump Adaptive Adjustment To ensure the stable operation of the hydraulic system, it improves the intelligence level of the hydraulic system and has higher versatility.

[0087] In adjustment Afterwards, the controller can collect the pressure of port A of the boom cylinder through pressure sensor 6.3 and pressure sensor 6.4 respectively. , B port pressure , to determine the load pressure at the boom cylinder Specifically, the controller can identify the movement direction of the boom cylinder according to the handle command signal. When the oil is inlet at port A and outlet at port B, the controller can determine the load pressure. ; When oil is inlet at port B and outlet at port A, the controller can determine the load pressure .

[0088] like Figure 4 As shown, the load pressure is After that, the controller can output the control pressure of the pump ,in, . The value range can be 5 to 30 bar. The controller can also collect the output pressure of the load sensing pump through the pressure sensor 6.1 . After obtaining the output pressure of the load sensing pump After that, the controller can control the pressure and output pressure Perform pressure PID closed-loop control.

[0089] Specifically, the controller can determine the control pressure and output pressure The pressure difference between The controller can also obtain the engine speed n and determine the closed-loop parameters based on the engine speed. ,in, is the pressure closed loop proportional term parameter, is the pressure closed loop integral parameter, , , , , , It is a regulation parameter determined based on the working condition of the engineering machinery where the hydraulic system is located. The controller can determine the control displacement based on the control pressure and the flow output characteristics of the pump, where the flow output characteristics of the pump can include the engine speed , oil temperature , pressure closed-loop parameters and displacement closed-loop parameters, etc. Among them, the control displacement may include a first displacement (corresponding to the feedforward displacement of the pressure closed-loop control below) and a second displacement (corresponding to the pressure closed-loop PID output displacement below). Specifically, the controller may adjust the engine speed according to the engine speed. , control pressure and oil temperature Determine the feedforward displacement for closed-loop pressure control ,Right now The controller can also adjust the closed loop parameters and pressure difference Determine the pressure closed loop PID output displacement ,Right now . After obtaining the feedforward displacement and PID output displacement The controller can then determine the control displacement X for the LS valve = . After obtaining the controlled displacement X The controller can then control the displacement based on X Determining the feedforward current , you can also collect the first joint displacement , and based on the displacement and control displacement Perform displacement PID closed-loop control.

[0090] Specifically, the controller can generate a control signal according to the control displacement, wherein the control signal can be a control current acting on the LS valve 2.3, and the control signal can be determined based on a first control signal and a second control signal, wherein the first control signal can be a displacement closed-loop feedforward current, and the second control signal can be a displacement closed-loop PID output current. X Determine the displacement closed-loop feedforward current ,Right now ,in, , It is a control parameter determined based on the working conditions of the engineering machinery where the hydraulic system is located. The controller can determine the control displacement X and the displacement The displacement difference between In determining the displacement difference Afterwards, the controller Determine the displacement closed loop PID output current ,Right now ,in, , is a closed-loop parameter determined based on the engine speed, where is the displacement closed-loop proportional term parameter, is the displacement closed loop integral parameter. and displacement closed loop PID output current The processor can then shift the closed-loop feedforward current and displacement closed loop PID output current The sum of is determined as the control current I, that is, The control current I is applied to the LS valve 2.3 to adjust the output pressure of the load-sensitive pump to the control pressure, thereby realizing dual closed-loop control of pressure and displacement, adjusting the control pressure in real time, and improving the control accuracy of the hydraulic system.

[0091] In one possible implementation, Figure 5As shown, the hydraulic system may include a handle, a main controller, two pilot controllers, a first joint, a main pump, a working joint and an actuator. The main controller may obtain the voltage signal transmitted by the handle, and may also collect the pump port pressure of the first joint and the working oil port pressure of the working joint, wherein the pump port pressure of the first joint and the working oil port pressure of the working joint may both be analog quantities, and the pilot controller of the first joint may feedback the displacement of the first joint to the main controller in real time through the bus, and the pilot controller of the working joint may feedback the displacement of the working joint to the main controller in real time through the bus. The main controller may determine the control current according to the handle command signal, the pump port oil pressure, the working oil port pressure of the actuator and the engine speed, and transmit the control current to the pilot controllers of the first joint and the working joint through the bus, so that the pilot controller of the first joint outputs the corresponding pilot oil pressure to the first joint, and the pilot controller of the working joint outputs the corresponding pilot oil pressure to the working joint to drive the actuator, thereby adjusting the oil pressure of the LS valve, so as to adjust the pressure of the main pump, so that the pressure of the main pump reaches the control pressure, and realizes rapid matching of the pump and valve, and reduces the response time.

[0092] Through the above technical solution, rapid matching between the pump and the valve is achieved, the response time is reduced, the control accuracy of the pump is improved, and the intelligence level of the hydraulic system is improved.

[0093] Figure 1 and Figure 3 FIG. 1 is a flow chart of a control method for a hydraulic system in one embodiment. It should be understood that although Figure 1 and Figure 3 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1 and Figure 3 At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0094] The present application also provides a control device for a hydraulic system, comprising:

[0095] a memory configured to store instructions;

[0096] The processor is configured to call instructions from the memory and implement the above-mentioned control method for the hydraulic system when executing the instructions.

[0097] The present application also provides a hydraulic system, including:

[0098] LS valve, used to adjust the output pressure of the pump;

[0099] Pumps;

[0100] Actuator;

[0101] Prime mover;

[0102] The above-mentioned control device for the hydraulic system.

[0103] In the embodiments of the present application, Figure 6 As shown, the hydraulic system is a dual valve core system, which may include a load sensing pump 1, a filter 2.1, a pilot oil pressure reducing valve 2.2, a first-link pilot solenoid valve 2.3, an LS valve core 2.4, a pressure sensor 6.1, a pressure sensor 6.2, a pressure sensor 6.3, a pressure sensor 6.4, a boom cylinder 7.1, a controller 8 and a handle 9.

[0104] An embodiment of the present application also provides an operating equipment, comprising the above-mentioned hydraulic system.

[0105] In some examples, the operating equipment may be new energy equipment, including but not limited to new energy vehicles, new energy vehicle cranes, new energy truck cranes, new energy mixer trucks, new energy pump trucks, new energy fire trucks, new energy road construction vehicles, new energy sanitation vehicles, etc. The prime mover may include an electric motor, and the new energy equipment may also include a power battery (such as a lithium battery, a hydrogen fuel cell, etc.) for powering the electric motor.

[0106] Of course, the operating equipment of the present application can also be fuel-powered equipment, which includes, but is not limited to, cars driven by fuel engines, truck cranes, truck cranes, mixer trucks, pump trucks, fire trucks, road construction vehicles, sanitation vehicles, etc. The prime mover can be an engine in the fuel-powered equipment; or, the prime mover can be an electric motor, and accordingly, the fuel-powered equipment also includes a generator, which can drive the generator to run when the engine is running, and then the generator can supply power to the motor.

[0107] An embodiment of the present application also provides a machine-readable storage medium, on which instructions are stored, and the instructions are used to enable a machine to execute the above-mentioned control method for a hydraulic system.

[0108] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 7As shown. The computer device includes a processor A01, a network interface A02, a memory (not shown in the figure) and a database (not shown in the figure) connected through a system bus. Among them, the processor A01 of the computer device is used to provide computing and control capabilities. The memory of the computer device includes an internal memory A03 and a non-volatile storage medium A04. The non-volatile storage medium A04 stores an operating system B01, a computer program B02 and a database (not shown in the figure). The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 in the non-volatile storage medium A04. The database of the computer device is used to store data such as load pressure, adjustment factors, preset pressure difference thresholds, control pressure, control signals, etc. The network interface A02 of the computer device is used to communicate with an external terminal through a network connection. When the computer program B02 is executed by the processor A01, a control method for a hydraulic system is implemented.

[0109] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0110] An embodiment of the present application provides a device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, the following steps are implemented: obtaining the load pressure of the actuator and the regulating factors for the LS valve, the regulating factors including the oil temperature, the output pressure of the pump, the flow difference corresponding to the actuator, and at least one of the rotational speed of the prime mover; determining a preset pressure difference threshold value according to the regulating factors and a preset relationship, wherein the preset relationship records the relationship between the regulating factors and the preset pressure difference threshold value, the oil temperature, the output pressure, and the flow difference may all be positively correlated with the preset pressure difference threshold value, and the rotational speed may be negatively correlated with the preset pressure difference threshold value; determining the control pressure according to the load pressure and the preset pressure difference threshold value; generating a control signal for the LS valve based on the control pressure, the control signal being used to adjust the output pressure of the pump to the control pressure.

[0111] In one embodiment, the hydraulic system also includes a valve core connected to the oil inlet of the actuator, and the control method also includes: before obtaining the load pressure of the actuator and the adjustment factor for the LS valve, when receiving the handle command signal, obtaining the first actual displacement of the valve core; determining the pressure difference between the output pressure of the pump and the load pressure; determining the actual flow at the oil inlet of the actuator based on the pressure difference and the first actual displacement; and determining the difference between the flow corresponding to the handle command signal and the actual flow as the flow difference.

[0112] In one embodiment, generating a control signal for the LS valve based on the control pressure includes: determining a control displacement according to the control pressure and a flow output characteristic of a pump; and generating a control signal according to the control displacement.

[0113] In one embodiment, determining the control displacement according to the control pressure and the flow output characteristics of the pump includes: determining a first displacement according to the control pressure and the flow output characteristics of the pump; determining a second displacement according to the control pressure and the actual pressure at the outlet of the pump; and determining the control displacement according to the first displacement and the second displacement.

[0114] In one embodiment, generating a control signal according to a control displacement includes: acquiring an actual displacement of the LS valve; determining a first control signal according to the control displacement; determining a second control signal according to a displacement difference between the control displacement and the actual displacement; and determining a control signal according to the first control signal and the second control signal.

[0115] In one embodiment, determining the second control signal according to the displacement difference between the control displacement and the actual displacement includes: determining a closed-loop control parameter according to the rotation speed; and determining the second control signal according to the displacement difference and the closed-loop control parameter.

[0116] In one embodiment, the control method further includes: before determining the preset pressure difference threshold value according to the adjustment factor and the preset relationship, judging whether the flow rate of the pump has reached a saturated state; when the flow rate of the pump has reached a saturated state, determining the preset pressure difference threshold value as a preset pressure difference lower limit value.

[0117] The present application also provides a computer program product which, when executed on a data processing device, is suitable for executing a program of initializing the steps of a control method for a hydraulic system.

[0118] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program codes.

[0119] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of the processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0120] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0121] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0122] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0123] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0124] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0125] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0126] The above are only embodiments of the present application and are not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included within the scope of the claims of the present application.

Claims

1. A control method for a hydraulic system, characterized in that: The hydraulic system includes an actuator, a prime mover, an LS valve and a pump, wherein the LS valve is used to adjust the output pressure of the pump, and the control method includes: Acquiring a load pressure of the actuator and a regulating factor for the LS valve, wherein the regulating factor includes at least one of an oil temperature, an output pressure of the pump, a flow difference corresponding to the actuator, and a rotation speed of the prime mover; Determining a preset differential pressure threshold value according to the adjustment factor and the preset relationship, wherein the preset relationship records the relationship between the adjustment factor and the preset differential pressure threshold value, the oil temperature, the output pressure and the flow difference are all positively correlated with the preset differential pressure threshold value, and the rotation speed is negatively correlated with the preset differential pressure threshold value; determining a control pressure according to the load pressure and the preset pressure difference threshold; A control signal for the LS valve is generated based on the control pressure, the control signal being used to adjust the output pressure of the pump to the control pressure.

2. The control method for a hydraulic system according to claim 1, characterized in that: The hydraulic system further includes a valve core connected to an oil inlet of the actuator, and the control method further includes: Before obtaining the load pressure of the actuator and the adjustment factor for the LS valve, obtaining a first actual displacement of the valve core when receiving a handle command signal; determining a pressure difference between an output pressure of the pump and the load pressure; determining an actual flow rate at an oil inlet of the actuator according to the pressure difference and the first actual displacement; The difference between the flow rate corresponding to the handle command signal and the actual flow rate is determined as the flow rate difference.

3. The control method for a hydraulic system according to claim 1, characterized in that: Generating a control signal for the LS valve based on the control pressure includes: determining a control displacement according to the control pressure and a flow output characteristic of the pump; The control signal is generated according to the control displacement.

4. The control method for a hydraulic system according to claim 3, characterized in that: Determining the control displacement according to the control pressure and the flow output characteristic of the pump comprises: determining a first displacement according to the control pressure and a flow output characteristic of the pump; determining a second displacement according to the control pressure and an actual pressure at an outlet of the pump; The control displacement is determined based on the first displacement and the second displacement.

5. The control method for a hydraulic system according to claim 3, characterized in that: Generating the control signal according to the control displacement comprises: Obtaining the actual displacement of the LS valve; determining a first control signal according to the control displacement; determining a second control signal according to a displacement difference between the control displacement and the actual displacement; The control signal is determined according to the first control signal and the second control signal.

6. The control method for a hydraulic system according to claim 5, characterized in that: Determining the second control signal according to the displacement difference between the control displacement and the actual displacement comprises: determining a closed-loop control parameter according to the rotational speed; The second control signal is determined according to the displacement difference and the closed-loop control parameter.

7. The control method for a hydraulic system according to claim 1, characterized in that: The control method further comprises: Before determining the preset pressure difference threshold according to the adjustment factor and the preset relationship, judging whether the flow rate of the pump reaches a saturation state; When the flow rate of the pump reaches a saturated state, the preset pressure difference threshold is determined to be a preset pressure difference lower limit value.

8. A control device for a hydraulic system, characterized in that: include: a memory configured to store instructions; A processor is configured to call the instructions from the memory and implement the control method for a hydraulic system according to any one of claims 1 to 7 when executing the instructions.

9. A hydraulic system, characterized in that: include: LS valve, used to adjust the output pressure of the pump; the pump; Actuator; Prime mover; A control device for a hydraulic system according to claim 8.

10. A machine-readable storage medium, characterized in that: The machine-readable storage medium stores instructions, which are used to enable a machine to execute the control method for a hydraulic system according to any one of claims 1 to 7.

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