Hydraulic system, control method and rescue apparatus

Abstract

A hydraulic system, a control method and a rescue apparatus, which aim to solve problems such as difficult flow distribution and slow response in engineering machinery apparatuses. The hydraulic system comprises a hydraulic pump (4), a common rail line (14), a controller (6), at least one actuator mechanism and a reversing valve (9) corresponding to each actuator mechanism, wherein the hydraulic pump (4) is connected to the common rail line (14); the reversing valve (9) is located between the actuator mechanism and the common rail line (14); and the controller (6) is used for determining a target total demand flow rate on the basis of a target speed corresponding to each actuator mechanism, and determining a target common rail pressure on the basis of a load pressure. When it is determined that a target total power determined on the basis of the target common rail pressure does not exceed a limited total power of the hydraulic system, and the sum of oil demand flow rates determined on the basis of the target speeds does not exceed a limited total flow rate of the hydraulic system, for each actuator mechanism, a valve control current of the reversing valve corresponding to the actuator mechanism is determined on the basis of the load pressure of the actuator mechanism, and the valve control current is supplied to the reversing valve.

Description

Hydraulic system, control method and rescue equipment

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to the Chinese patent application filed with the China Patent Office on December 25, 2023, with application number 202311786328.6 and application name “A Hydraulic System, Control Method and Rescue Equipment”, the entire contents of which are incorporated by reference into this application. Technical Field

[0003] The present application relates to the field of engineering machinery, and in particular to a hydraulic system, a control method and rescue equipment. Background Art

[0004] The hydraulic system is the core component of walking rescue equipment, and its performance directly affects the maneuverability, controllability, energy saving, etc. of the rescue equipment. At present, the industry mainly adopts positive flow hydraulic systems, negative flow hydraulic systems, load-sensitive hydraulic systems, etc., all of which use integrated multi-way valves. As the core control unit in the hydraulic system, the multi-way valve undertakes the important functions of pressure control and flow distribution. In the existing technology, the hydraulic system related to the multi-way valve has a complex layout and numerous pipelines. Especially for the actuators far away from the multi-way valve, they will face problems such as slow response of the hydraulic system, large pressure loss along the way, high risk of oil leakage, and difficulty in flow distribution when multiple mechanisms act in combination.

[0005] Summary of the Invention

[0006] The embodiments of the present application provide a hydraulic system, a control method, and rescue equipment to solve problems such as difficult flow distribution and slow response speed in engineering machinery.

[0007] In a first aspect, an embodiment of the present application provides a hydraulic system, the hydraulic system comprising a hydraulic pump, a common rail line, a controller, at least one actuator, and a reversing valve corresponding to each actuator;

[0008] The output end of the hydraulic pump is connected to the high-pressure pipeline in the common rail pipeline;

[0009] For each set of actuators and reversing valves, the first working oil port and the second working oil port of the reversing valve are respectively connected to the two ends of the actuator, the oil inlet of the reversing valve is connected to the high-pressure pipeline, and the oil return port of the reversing valve is connected to the low-pressure pipeline in the common rail pipeline;

[0010] The hydraulic pump is used to output high-pressure oil to the high-pressure pipeline in the common rail pipeline;

[0011] The common rail pipeline is used to deliver the high-pressure oil output by the hydraulic pump to the at least one actuator through the reversing valve;

[0012] The controller is used to determine the target speed and load pressure corresponding to each actuator in response to user operations;

[0013] determining a target total required flow rate of the hydraulic system according to a target speed corresponding to each actuator, and determining a target common rail pressure of the common rail line according to a maximum load pressure among the load pressures corresponding to each actuator;

[0014] When the target total power does not exceed the limited total power of the hydraulic system and the sum of the required oil flow rates does not exceed the limited total flow rate of the hydraulic system, for each actuator, a valve-controlled current of a reversing valve corresponding to the actuator is determined according to the load pressure of the actuator, and the valve-controlled current is supplied to the reversing valve; the target total power is determined based on the target common rail pressure, and the sum of the required oil flow rates is determined based on the target speed.

[0015] In a possible implementation, the at least one actuator includes a pressure sensor.

[0016] In a possible implementation, the high-pressure pipeline includes a common rail high-pressure sensor, and the low-pressure pipeline includes a common rail low-pressure sensor.

[0017] In a second aspect, an embodiment of the present application provides a method for controlling a hydraulic system, which is applied to the hydraulic system described in the first aspect. The method includes:

[0018] In response to user operations, determine the target speed and load pressure corresponding to each actuator;

[0019] determining a target total required flow rate of the hydraulic system according to a target speed corresponding to each actuator, and determining a target common rail pressure of the common rail line according to a maximum load pressure among the load pressures corresponding to each actuator;

[0020] When the target total power does not exceed the limited total power of the hydraulic system and the sum of the required oil flow rates does not exceed the limited total flow rate of the hydraulic system, for each actuator, a valve-controlled current of a reversing valve corresponding to the actuator is determined according to the load pressure of the actuator, and the valve-controlled current is supplied to the reversing valve; the target total power is determined based on the target common rail pressure, and the sum of the required oil flow rates is determined based on the target speed.

[0021] In one possible implementation, determining the target total required flow of the hydraulic system according to the target speed corresponding to each actuator includes:

[0022] For any actuator, the required oil flow rate of the actuator is determined according to the target speed of the actuator; and the sum of all the determined required oil flow rates is used as the target total required flow rate of the hydraulic system.

[0023] In one possible implementation, determining the target common rail pressure of the common rail pipeline based on the maximum load pressure among the load pressures corresponding to each actuator includes: obtaining a pressure differential adjustment coefficient and a system set pressure differential, and taking the product of the pressure differential adjustment coefficient and the system set pressure differential as the target pressure differential; and determining the target common rail pressure based on the target pressure differential and the maximum load pressure.

[0024] In one possible implementation, determining the valve-controlled current of the reversing valve corresponding to the actuator based on the load pressure of the actuator includes: for any actuator, determining a compensation current corresponding to the actuator through a control algorithm based on the current speed of the actuator, and determining a feedforward current corresponding to the actuator based on the load pressure, the flow regulation coefficient of the actuator, and the target common rail pressure; and using the sum of the compensation current and the feedforward current as the valve-controlled current of the reversing valve corresponding to the actuator.

[0025] In one possible implementation, the method further includes: when the target total power exceeds the limited total power, obtaining a current available engine power; and determining a pressure difference adjustment coefficient according to the current available engine power, the target common rail pressure, and the target total required flow rate.

[0026] In one possible implementation, the method further includes: when the sum of the oil demand flow determined by the target speed exceeds the limited total flow, obtaining the current engine speed and the set maximum displacement of the hydraulic pump; and determining the flow adjustment coefficient based on the current engine speed, the set maximum displacement and the sum of the oil demand flow.

[0027] In a third aspect, an embodiment of the present application provides a rescue device, comprising the hydraulic system as described in the first aspect and different implementations of the first aspect, or a control method for the hydraulic system as described in the second aspect and different implementations of the second aspect.

[0028] The beneficial effects of this application are as follows:

[0029] In this application, a hydraulic pump is connected to a common rail line. A reversing valve is connected to each actuator group, and the reversing valve is also connected to the common rail line. Upon user operation, a controller determines the target speed and load pressure corresponding to each actuator; determines the target total flow rate of the hydraulic system based on the target speed; and determines the target common rail pressure of the common rail line based on the load pressure. When it is determined that the target total power determined by the target common rail pressure does not exceed the hydraulic system's total power limit, and the target total flow rate determined by the target total flow rate does not exceed the hydraulic system's total flow limit, the valve control current for the reversing valve corresponding to each actuator is determined based on the actuator's load pressure, and the valve control current is supplied to the reversing valve. In this embodiment of the application, the multi-way valve is replaced with reversing valves distributed near each actuator, simplifying the hydraulic system and its piping layout and reducing system pressure losses. The hydraulic pump can directly deliver high-pressure oil to the actuator's load port through the common rail line. Furthermore, the application utilizes variable pressure common rail technology, which enables flow distribution and system pressure control throughout the hydraulic system. The use of electronic control to achieve hydraulic flow distribution greatly reduces the system's dependence on multi-way valve flow distribution, makes the system's response faster, and makes the whole machine's movement more agile and light. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0031] FIG1 is a schematic diagram of a load sensing system according to an embodiment of the present application;

[0032] FIG2 is a schematic diagram of a distributed common rail hydraulic system provided in an embodiment of the present application;

[0033] FIG3 is a schematic diagram of a control framework of a distributed common rail hydraulic system provided in an embodiment of the present application;

[0034] FIG4 is a flow chart of a control method for a hydraulic system provided in an embodiment of the present application;

[0035] FIG5 is a logic diagram of a control method for a hydraulic system provided in an embodiment of the present application;

[0036] FIG6 is a flow control principle diagram of a common rail hydraulic system provided in an embodiment of the present application;

[0037] FIG7 is a schematic diagram of a control device of a common rail hydraulic system provided in an embodiment of the present application. DETAILED DESCRIPTION

[0038] The following will be combined with the accompanying drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Generally, the components of the embodiments of the present application described and shown in the drawings herein can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for protection, but merely represents selected embodiments of the present application. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present application.

[0040] It should be noted that relational terms such as "first" and "second" are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus comprising the element.

[0041] The hydraulic system in the construction machinery industry is a core component of this equipment. It consists of a hydraulic pump, a multi-way valve, and an actuator. As the power source of the hydraulic system, the hydraulic pump is responsible for converting the mechanical energy of the machine into hydraulic energy and providing the required high-pressure oil to the hydraulic system. The multi-way valve regulates and controls the operation of the various components of the hydraulic system. It controls the flow and pressure of the oil according to operational requirements and ensures that the various actuators in the hydraulic system work together as required. The actuator is the final execution part of the hydraulic system, performing the hydraulic system's work according to control signals. The application of hydraulic system technology has enabled mechanical equipment to possess powerful working capacity and flexibility, capable of meeting the excavation needs of various working conditions. Furthermore, the hydraulic system is efficient, reliable, and safe, providing stable power support for the operation of the equipment.

[0042] At present, the industry mainly adopts positive flow hydraulic system, negative flow hydraulic system, load-sensing hydraulic system, etc., all of which use integrated multi-way valves. As shown in Figure 1, Figure 1 shows the structure of the load-sensing system by way of example. Among them, the system includes 3 actuators. Among them, the multi-way valve is framed by dotted lines, and the multi-way valve in the figure is integrated. For general medium-sized hydraulic excavators, the general multi-way valve has about 10 groups of valve cores, and the number of external high-pressure pipelines can reach about 12. However, for walking rescue machines, more than 20 groups of multi-way valves are required, and the number of external high-pressure pipelines is as high as more than 40. In addition, in specific rescue scenarios, more than 10 actions need to be operated simultaneously for coordinated operations, which places high demands on the flow distribution of the multi-way valve. It is difficult to achieve precise proportional distribution of flow distribution using hydraulic logic control.

[0043] Take the walking rescue machine, for example. It is a multifunctional rescue device for disaster sites, capable of a variety of basic movements, including full machine travel, vehicle slewing, boom raising and lowering, arm digging and unloading, bucket digging and unloading, outrigger raising and lowering, outrigger yaw, and wheel steering. These movements, totaling over twenty, require hydraulic systems and involve actuators in various locations. The multi-way valves are surrounded by over 40 high-pressure pipelines, creating a complex piping layout. Furthermore, the long distances between the multi-way valves and actuators, such as the working arm and chassis, can lead to pressure loss and oil leakage during hydraulic transmission, compromising the hydraulic system's responsiveness and efficiency. Furthermore, properly distributing system flow during the complex actions of multiple mechanisms presents a significant challenge.

[0044] Based on the above problems, an embodiment of the present application provides a hydraulic system, as shown in FIG2 , wherein the hydraulic system adopts a distributed common rail layout. The reversing valve part is at the inlet of each actuator, and the high-pressure oil generated by the hydraulic pump can be directly supplied to the load port of the actuator through the common rail pipeline. As shown in FIG2 , the various actuators shown in FIG2 are respectively a bucket cylinder, a telescopic arm cylinder, a dipper arm cylinder, a leg swing cylinder, a boom cylinder, a rotary motor, a claw cylinder, and a hydraulic pump. Each actuator is connected to the common rail pipeline in a distributed manner through a reversing valve. That is, in the present application, the flow direction of the high-pressure oil is: hydraulic pump → common rail pipeline → reversing valve → actuator.

[0045] Referring to FIG3 , FIG3 is a schematic structural diagram of a hydraulic system provided in an embodiment of the present application.

[0046] Among them, the hydraulic system includes a pressure sensor 1, a hydraulic cylinder 2, a hydraulic motor 3, a hydraulic pump 4, an engine 5, a controller (Vehicle Control Unit, VCU) 6, a pump swing angle sensor 7, a main overflow valve 8, a reversing valve 9, an electric proportional direct drive coil 10, a valve core displacement sensor 11, a common rail high-pressure sensor 12, a common rail low-pressure sensor 13 and a common rail pipeline 14.

[0047] The output end of the hydraulic pump 4 is connected to the high-pressure line of the common rail 14. The hydraulic cylinder 2 and hydraulic motor 3 serve as actuators. For each set of actuators and reversing valves 9, the first and second working oil ports of the reversing valves 9 are connected to the upper and lower chambers of the actuators, respectively. The oil inlet of the reversing valves 9 is connected to the high-pressure line of the common rail 14, and the oil return port of the reversing valves 9 is connected to the low-pressure line of the common rail 14.

[0048] In some embodiments, the hydraulic pump 4 is configured to output high-pressure oil to a common rail line 14. The common rail line 14 is configured to deliver the high-pressure oil output by the hydraulic pump 4 to the actuator via a reversing valve 9. For example, the high-pressure oil in the common rail line 14 can be delivered to the hydraulic cylinder 2 or the hydraulic motor 3 via the reversing valve 9.

[0049] In a possible implementation, the reversing valve 9 can be implemented by a three-position four-way reversing valve.

[0050] In some embodiments, the controller 6 is configured to determine the target speed and load pressure corresponding to each actuator in response to user operation. For example, the target handle opening can be determined based on the driver's operation, and the target actuator speed can be determined based on the corresponding relationship between the opening and the actuator speed. The hydraulic cylinder 2 and hydraulic motor 3 each include a pressure sensor 1, which can be used to determine the actuator load pressure.

[0051] Furthermore, a target total required flow rate for the hydraulic system can be determined based on the target speed corresponding to each actuator, and a target common rail pressure for the common rail line 14 can be determined based on the maximum load pressure among the load pressures corresponding to each actuator. Then, when it is determined that the target total power determined by the target common rail pressure does not exceed the limited total power of the hydraulic system, and the target total flow rate determined by the target total required flow rate does not exceed the limited total flow rate of the hydraulic system, a valve-controlled current for the corresponding reversing valve 9 is determined for each actuator based on the actuator's load pressure, and the valve-controlled current is supplied to the reversing valve 9.

[0052] In some embodiments, the two lines of the common rail line 14 respectively include a common rail high pressure sensor 12 and a common rail low pressure sensor 13. Specifically, the high pressure line of the common rail line 14 includes the common rail high pressure sensor 12, and the low pressure line of the common rail line 14 includes the common rail low pressure sensor 13.

[0053] In some scenarios, a system set pressure difference in the common rail line 14 may be determined by the common rail high pressure sensor 12 and the common rail low pressure sensor 13 .

[0054] The present application provides a method for controlling a hydraulic system, as shown in FIG4 . The method can be executed by the hydraulic system shown in FIG3 , specifically by the controller 6 in the hydraulic system. For ease of description, reference numerals are no longer used to identify the various components. The specific process is as follows:

[0055] 401 , in response to a user operation, determining a target speed and a load pressure corresponding to each actuator.

[0056] 402 , determining a target total required flow of the hydraulic system according to a target speed corresponding to each actuator, and determining a target common rail pressure of the common rail line according to a maximum load pressure among the load pressures corresponding to each actuator.

[0057] In some embodiments, for any actuator, the required oil flow rate of the actuator can be determined according to the target speed of the actuator, and the target total required oil flow rate of the hydraulic system can be determined according to the sum of all required oil flow rates.

[0058] Specifically, the product of the sum of the oil demand flow and the flow adjustment coefficient can be used as the target total demand flow of the hydraulic system. As an example, the target total demand flow satisfies the conditions shown in the following formula: Q Tt =K Q *Q t ;

[0059] Among them, Q Tt Used to express the target total demand flow, K Q Used to express the flow regulation coefficient, Q t Used to indicate the sum of required oil flow rates.

[0060] Among them, Q t =Q a +Q2+Q3+…+Q n , Q1, Q2, Q3, …, Q n Used to indicate the required oil flow of each actuator.

[0061] In some embodiments, when the hydraulic cylinder is extended, the required oil flow rate satisfies the following formula: Q n=3.14*D n 2 *0.25*V n ;

[0062] Among them, D n Used to indicate the cylinder diameter of the hydraulic cylinder, V n Used to indicate the target speed of the hydraulic cylinder.

[0063] In some embodiments, when the hydraulic cylinder retracts, the required oil flow rate satisfies the following formula: Q n =3.14*(D n 2 -d n 2 )*0.25*V n ;

[0064] Among them, d n Used to indicate the rod diameter of a hydraulic cylinder.

[0065] In some embodiments, when the actuator is a hydraulic motor, the required oil flow rate satisfies the following formula: Q n =V gn *n n *i n *η n ;

[0066] Among them, V gn Used to indicate the displacement of hydraulic motor, n n Used to indicate the target speed of the hydraulic motor, i.e. the target speed, i n Used to express the speed ratio of the hydraulic motor, η n Used to indicate the volumetric efficiency of a hydraulic motor.

[0067] In some embodiments, the target speed of each actuator satisfies the following conditions: V n =V max-n *X n ;

[0068] Among them, V n represents the target speed of actuator n, V max-n Used to indicate the maximum set speed of actuator n, X n Indicates the user's operation instructions.

[0069] In some scenarios, the user can execute multiple operation instructions on multiple actuators separately, so that the multiple actuators can complete a compound action together.

[0070] In some embodiments, the target common rail pressure may be determined by obtaining a pressure differential adjustment coefficient and a system set pressure differential, and multiplying the pressure differential adjustment coefficient and the system set pressure differential as the target pressure differential. Furthermore, the target common rail pressure may be determined based on the target pressure differential and the maximum load pressure.

[0071] As an example, the target common rail pressure satisfies the following conditions: P R =P L +ΔP;

[0072] Among them, P R Used to indicate the target common rail pressure, P L It is used to indicate the maximum load pressure, and ΔP is used to indicate the target pressure difference.

[0073] In some scenes, P L =MAX(P L1 、P L2 、P L3 ,…P Ln ), where P L1 、P L2 、P L3 ,…,P Ln Used to indicate the load pressure of each actuator.

[0074] In some scenarios, ΔP=ΔP0*K p , where ΔP0 is used to represent the system set pressure difference, K p In some embodiments, in the first cycle, K p The default value is 1, which can be further determined through subsequent calculations.

[0075] 403. When the target total power does not exceed the limited total power of the hydraulic system and the sum of the required oil flow rates does not exceed the limited total flow rate of the hydraulic system, for each actuator, the valve control current of the reversing valve corresponding to the actuator is determined according to the load pressure of the actuator, and the valve control current is provided to the reversing valve.

[0076] In some embodiments, the target total power is determined based on the target common rail pressure, and the sum of the required oil flow rates is determined based on the target speed.

[0077] In some embodiments, the target total power may be determined by the target common rail pressure and the target total required flow rate, and compared with the limited total power of the hydraulic system to determine whether the target total power exceeds the limited total power.

[0078] In some embodiments, determining the valve-controlled current of the reversing valve corresponding to at least one actuator based on the load pressure of the at least one actuator can be achieved by: for each actuator, determining the corresponding compensation current using a control algorithm based on the actuator's current speed, and determining the corresponding feedforward current based on the load pressure, the actuator's flow adjustment coefficient, and the target common rail pressure. In some scenarios, each actuator includes a displacement velocity sensor, and the current velocity of each actuator can be obtained using the displacement velocity sensor.

[0079] Furthermore, the sum of the compensation current and the feedforward current can be used as the valve control current of the reversing valve corresponding to the actuator.

[0080] As an example, the valve control current of each actuator is divided into two parts, feedforward current and compensation current. The compensation current can be determined by PID algorithm. The valve control current meets the conditions shown in the following formula: n =I FFWn +I PIDn ;

[0081] Among them, I n Used to indicate the valve control current of actuator n, I FFWn Used to represent the feedforward current of the execution structure n; I PIDn This is used to represent the compensation current of actuator n. The compensation current can be used to obtain the actual speed of the actuator through a displacement velocity sensor, encoder, etc., and PID control is performed using the PID current value as the controlled variable.

[0082] In some embodiments, the feedforward current satisfies I FFWn =f(A N ), where f(x) is used to represent the valve core opening area-valve control current function model, which is related to the opening characteristics of the reversing valve and is generally a cubic function fitting.

[0083] In some embodiments, the valve core opening area satisfies Among them, A N Used to indicate the valve core opening area of ​​the reversing valve corresponding to the actuator n; K Q It is used to express the flow rate adjustment coefficient, which is related to the valve core structure. n =P R -P Ln , △Pn is used to represent the actual pressure difference before and after the valve of actuator n, △P n It can be determined by the difference between the rail pressure sensor and the pressure sensor in the actuator n.

[0084] In some embodiments, when the target total power exceeds the limited total power, the currently available engine power is obtained. In some scenarios, the currently available engine power is the maximum net power that the engine can provide at the current speed. In some scenarios, the currently available power of the actuator can change based on user operation instructions.

[0085] Furthermore, a new pressure difference adjustment coefficient may be determined according to the current available engine power, the target common rail pressure, and the target total required flow rate.

[0086] As an example, the pressure difference adjustment coefficient satisfies the conditions described in the following formula: K p =[1,0];

[0087] Among them, K p Used to express the pressure difference adjustment coefficient, P EA Indicates the current available engine power, P R Indicates the target common rail pressure, Q Tt Used to express the target total demand flow.

[0088] In some embodiments, when the target total flow exceeds the limited total flow, the current engine speed and the set maximum displacement of the hydraulic pump are obtained.

[0089] Furthermore, the flow adjustment coefficient can be determined based on the current engine speed, the set maximum displacement, and the required oil flow rate corresponding to each actuator. In some embodiments, the engine includes a displacement speed sensor, and the current engine speed can be obtained through the displacement speed sensor.

[0090] As an example, the current maximum flow of the hydraulic system can be determined based on the current engine speed and the set maximum displacement, and the ratio of the current maximum flow to the sum of the oil demand can be used as the flow adjustment coefficient. For example, the flow adjustment coefficient satisfies the conditions shown in the following formula: K Q =n E *V gp / Q t ; K Q =[1,0];

[0091] Among them, n E Used to indicate the current engine speed, V gp Used to indicate the maximum displacement of the hydraulic pump, Q t Used to indicate the sum of the oil flow requirements of each actuator.

[0092] In some embodiments, in response to user operations, the target speed and load pressure of each actuator are determined according to the operation instructions, and the target total required flow and target common rail pressure are calculated. Further, it is determined whether the target total power determined by the target common rail pressure is met, that is, whether the target total power exceeds the limited total power of the hydraulic system. In some scenarios, when it is determined that the target total power determined by the target common rail pressure does not exceed the limited total power of the hydraulic system, it is determined whether the sum of the oil demand flow determined by the target speed meets the requirements, that is, whether the sum of the oil demand flow exceeds the limited total flow of the hydraulic system. Otherwise, the pressure difference adjustment coefficient K is adjusted. p , and recalculate the target common rail pressure based on the adjusted pressure difference adjustment coefficient. When the sum of the oil demand flow determined by the target speed does not exceed the limited total flow of the hydraulic system, calculate the valve control current corresponding to each actuator, otherwise, determine the flow adjustment coefficient K Q , and recalculate the target total demand flow, as shown in Figure 5.

[0093] Based on the above scheme, by adjusting the pressure difference adjustment coefficient and the flow adjustment coefficient based on the limited total power and the limited total flow, and then determining the new target common rail pressure and the target total required flow, each actuator can obtain sufficient flow within the capacity of the hydraulic system.

[0094] In one possible implementation, the controller can determine the handle angle of the operating handle and the load pressure of each load (i.e., actuator) according to the user's operating instructions. In some scenarios, different actuators correspond to different operating handles. After the user operates the operating handles corresponding to different actuators, the handle angles of each operating handle can be obtained. Furthermore, the maximum load pressure Pmax can be determined based on the load pressure of each load, and compared with the system set pressure difference △P max Determine the target common rail pressure Pr. In some embodiments, the setting parameters of each valve core can be determined by the valve core structure of each reversing valve. The setting parameters are provided by the manufacturer or obtained through testing. When Pr does not exceed the limited total power, determine the oil flow requirements Q1, Q2, Q3, ..., Q n , and determines the valve core opening areas A1...An and hydraulic pump control current Ip for each load. In some scenarios, the target common rail pressure can be used to determine the hydraulic pump control current Ip, which in turn controls the hydraulic pump outlet pressure, i.e., the pressure in the common rail line. Furthermore, the valve core opening areas A1...An for each load are used to determine the valve core openings associated with each load, and the control currents I1,...In for each reversing valve are determined based on these openings, as shown in Figure 6.

[0095] In this application, compared to traditional valve-controlled systems, the variable pressure common rail hydraulic system introduces the concept of variable pressure differential, transforming the hydraulic system into a pump-controlled system. During operation, the valve core is opened as far as possible, and the flow rate is adjusted by controlling the pressure differential, thereby reducing pressure losses in the entire system circuit and improving fuel economy. Furthermore, the hydraulic system can be equipped with additional hydraulic power sources by simply adding an oil tap to the common rail line, which is quick and convenient.

[0096] Based on the same technical concept, as shown in FIG7 , an embodiment of the present application provides a control device 700 for a hydraulic system. This device 700 can perform any step of the above-described control method for a hydraulic system. To avoid repetition, the details are omitted here. The device 700 includes a first determination unit 701 and a second determination unit 702.

[0097] The first determining unit 701 is configured to determine the target speed and load pressure corresponding to each actuator in response to a user operation;

[0098] determining a target total required flow rate of the hydraulic system according to all determined target speeds, and determining a target common rail pressure of the common rail line according to a maximum load pressure among all determined load pressures;

[0099] The second determining unit 702 is configured to determine, for each actuator, a valve-controlled current for a reversing valve corresponding to the actuator based on the load pressure of the actuator, and provide the valve-controlled current to the reversing valve when it is determined that the target total power determined by the target common rail pressure does not exceed the limited total power of the hydraulic system and the sum of the required oil flow rates determined by the target speed does not exceed the limited total flow rate of the hydraulic system.

[0100] In some embodiments, when determining the target total required flow rate of the hydraulic system according to all determined target speeds, the first determining unit 701 is specifically configured to:

[0101] For any actuator, determining the required oil flow rate of the actuator according to the target speed of the actuator;

[0102] The sum of all determined oil demand flow rates is used as the target total demand flow rate of the hydraulic system.

[0103] In some embodiments, when determining the target common rail pressure of the common rail pipeline according to the maximum load pressure among all determined load pressures, the first determining unit 701 is specifically configured to:

[0104] Obtaining a pressure differential adjustment coefficient and a system set pressure differential, and taking the product of the pressure differential adjustment coefficient and the system set pressure differential as a target pressure differential;

[0105] A target common rail pressure is determined based on the target pressure difference and the maximum load pressure.

[0106] In some embodiments, when determining the valve-controlled current of the reversing valve corresponding to the actuator according to the load pressure of the actuator, the second determining unit 702 is specifically configured to:

[0107] For any actuator, a compensation current corresponding to the actuator is determined by a control algorithm according to the current speed of the actuator, and a feedforward current corresponding to the actuator is determined according to the load pressure, the flow regulation coefficient of the actuator, and the target common rail pressure;

[0108] The sum of the compensation current and the feedforward current is used as the valve control current of the reversing valve corresponding to the actuator.

[0109] In some embodiments, the second determining unit 702 is further configured to obtain a current available engine power when the target total power exceeds the limited total power; and determine a pressure difference adjustment coefficient based on the current available engine power, the target common rail pressure, and the target total required flow rate.

[0110] In some embodiments, the second determination unit 702 is also used to obtain the current engine speed and the set maximum displacement of the hydraulic pump when the sum of the oil demand flow determined by the target speed exceeds the limited total flow; and determine the flow adjustment coefficient based on the current engine speed, the set maximum displacement and the sum of the oil demand flow.

[0111] On the other hand, the present application provides a computer-readable storage medium, which stores computer instructions. When the computer instructions are executed on a controller, the controller executes any one of the hydraulic system control methods provided in the embodiments of the present application.

[0112] On the other hand, an embodiment of the present application provides a computer program product, comprising a computer program, which, when executed by a controller, implements any one of the hydraulic system control methods provided in the embodiments of the present application.

[0113] The present invention also provides a rescue device, which may include the hydraulic system provided in the present invention, or the controller of the hydraulic system provided in the present invention. The vehicle provided in the present invention may implement any of the hydraulic system control methods provided in the present invention.

[0114] Those skilled in the art will appreciate that the embodiments of the present application can be provided as methods, systems, or computer program products. Therefore, the present application can adopt the form of a complete hardware embodiment, a complete software embodiment, or an embodiment in combination with software and hardware. Moreover, the present application can adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to magnetic disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0115] 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 present application. It should be understood that each flow and / or box in the flow chart and / or block diagram, as well as the combination of the flow chart and / or box in the flow chart 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 produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device produce a device for implementing the functions specified in one or more flow charts and / or one or more boxes in the block diagram.

[0116] These computer program instructions may also be stored in a computer-readable memory that can direct 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 a product including an instruction device that implements the functions specified in one or more processes in the flowchart and / or one or more boxes in the block diagram.

[0117] These computer program instructions may 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, whereby the instructions executed on the computer or other programmable device provide steps for implementing the functions specified in one or more flows of the flowchart and / or one or more blocks of the block diagram. Obviously, those skilled in the art may make various changes and modifications to the present application without departing from the spirit and scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is also intended to include such modifications and variations.

Claims

1. A hydraulic system, characterized in that, The hydraulic system includes a hydraulic pump, a common rail pipeline, a controller, at least one actuator, and a reversing valve corresponding to each actuator; The output end of the hydraulic pump is connected to the high-pressure pipeline in the common rail pipeline; For each group of actuators and reversing valves, the first working oil port and the second working oil port of the reversing valve are respectively connected to the upper and lower cavities of the actuator, the oil inlet of the reversing valve is connected to the high-pressure pipeline, and the oil return port of the reversing valve is connected to the low-pressure pipeline in the common rail pipeline; The hydraulic pump is used to output high-pressure oil to the high-pressure pipeline in the common rail pipeline; The common rail pipeline is used to transport the high-pressure oil output by the hydraulic pump to the at least one actuator through the reversing valve; The controller is used to respond to the user's operation to determine the target speed and load pressure corresponding to each actuator; According to the target speed corresponding to each actuator, determine the target total demand flow rate of the hydraulic system, and according to the maximum load pressure among the load pressures corresponding to each actuator, determine the target common rail pressure of the common rail pipeline; When the target total power does not exceed the defined total power of the hydraulic system, and the sum of the oil demand flow rates does not exceed the defined total flow rate of the hydraulic system, for each actuator, determine the valve control current of the reversing valve corresponding to the actuator according to the load pressure of the actuator, and provide the valve control current to the reversing valve; the target total power is determined based on the target common rail pressure, and the sum of the oil demand flow rates is determined based on the target speed.

2. The hydraulic system according to claim 1, characterized in that, The at least one actuator is provided with a pressure sensor.

3. The hydraulic system according to claim 1 or 2, characterized in that, The high-pressure pipeline is provided with a common rail high-pressure sensor, and the low-pressure pipeline is provided with a common rail low-pressure sensor.

4. A control method for a hydraulic system, characterized in that, Applied to the hydraulic system according to any one of claims 1 to 3, the method includes: Responding to the user's operation to determine the target speed and load pressure corresponding to each actuator; According to the target speed corresponding to each actuator, determine the target total demand flow rate of the hydraulic system, and according to the maximum load pressure among the load pressures corresponding to each actuator, determine the target common rail pressure of the common rail pipeline; When the target total power does not exceed the defined total power of the hydraulic system, and the sum of the oil demand flow rates does not exceed the defined total flow rate of the hydraulic system, for each actuator, determine the valve control current of the reversing valve corresponding to the actuator according to the load pressure of the actuator, and provide the valve control current to the reversing valve; the target total power is determined based on the target common rail pressure, and the sum of the oil demand flow rates is determined based on the target speed.

5. The method according to claim 4, wherein The determining the target total demand flow rate of the hydraulic system according to the target speed corresponding to each actuator includes: For any one actuator, determine the oil demand flow rate of the actuator according to the target speed of the actuator; Take the sum of all determined oil demand flow rates as the target total demand flow rate of the hydraulic system.

6. The method according to claim 4, wherein The determining the target common rail pressure of the common rail pipeline according to the maximum load pressure among the load pressures corresponding to each actuator includes: Obtain the differential pressure regulation coefficient and the system-set differential pressure, and use the product of the differential pressure regulation coefficient and the system-set differential pressure as the target pressure difference; Determine the target common rail pressure according to the target pressure difference and the maximum load pressure.

7. The method according to claim 4, wherein The determining the valve control current of the directional valve corresponding to the actuator according to the load pressure of the actuator includes: For any actuator, determine the compensation current corresponding to the actuator through a control algorithm according to the current speed of the actuator, and determine the feedforward current corresponding to the actuator according to the load pressure, the flow regulation coefficient of the actuator, and the target common rail pressure; Use the sum of the compensation current and the feedforward current as the valve control current of the directional valve corresponding to the actuator.

8. The method according to claim 6, wherein The method further includes: When the target total power exceeds the limited total power, obtain the currently available engine power; Determine the differential pressure regulation coefficient according to the currently available engine power, the target common rail pressure, and the target total demand flow rate.

9. The method according to claim 7, characterized in that, The method further includes: When the sum of the oil demand flow rates determined by the target speed exceeds the limited total flow rate, obtain the current engine speed and the set maximum displacement of the hydraulic pump; Determine the flow regulation coefficient according to the current engine speed, the set maximum displacement, and the sum of the oil demand flow rates.

10. A rescue device, characterized in that, It includes the hydraulic system according to any one of claims 1 to 3, or the control method for implementing the hydraulic system according to any one of claims 4 to 9.

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