Split electro-hydrostatic actuator for engineering machinery and control method thereof

Abstract

The invention discloses an engineering machinery split electro-hydrostatic actuator and a control method thereof. The split electro-hydrostatic actuator for the engineering machinery comprises an integrated power source assembly and actuator units configured remotely, wherein hydraulic pressure generated by the integrated power source assembly is supplied to the actuator units such as a hydraulic cylinder through a flexible hydraulic pipeline. In addition, the controller can control the motor to work according to working parameters fed back by the sensor assembly through a multi-loop control method. The split type layout design is combined with a multi-loop control method, and an operation system which is good in dynamic performance, high in response speed, low in operation noise and good in heat dissipation performance is achieved.

Description

Technical Field

[0001] The present application relates to the technical field of engineering machinery operation, and in particular to a split-type electrostatic hydraulic actuator for engineering machinery and a control method thereof. Background Art

[0002] The existing electric construction machinery operation system mainly adopts a centralized power configuration, which mainly uses a high-power motor to drive a load-sensitive pump, and then uses a hydraulic valve for throttling control to drive the boom, dipper and other actuators of the construction machinery. Although the load-sensitive pump can adjust the output pressure of the hydraulic pump according to the load pressure, the pressures between the actuators are still coupled to each other, and the energy loss of throttling control is large, resulting in low system energy efficiency.

[0003] Existing electrostatic hydraulic actuators control the actions of each actuator by adjusting the motor speed, thus achieving decoupling control of each actuator and avoiding throttling loss. However, the electrostatic hydraulic actuators with current patents are all integrated power configurations, and still have the following problems: 1. The integrated electrostatic hydraulic actuator needs to be installed on the boom or operating lever, which increases the overall weight of the boom or operating lever, generates additional load force during operation, and increases system energy consumption; 2. The integrated electrostatic hydraulic actuator is small in size and has poor heat dissipation performance. When the machine works for a long time, there is a risk of system overheating, and a high-power heat dissipation system is required, which increases system cost and reduces energy efficiency; 3. The integrated electrostatic hydraulic actuator uses a high-speed motor and a high-speed hydraulic pump, both of which have low efficiency at high speeds, and generate large noise during operation, affecting the working environment and the driver's operation. Summary of the invention

[0004] The purpose of the present application is to provide a split electrostatic hydraulic actuator for engineering machinery and a control method thereof, which can improve the above-mentioned problems.

[0005] The embodiment of the present application is implemented as follows:

[0006] In a first aspect, the present application provides a split electrostatic hydraulic actuator for engineering machinery, comprising:

[0007] An integrated power source assembly is installed on the rear platform of the engineering machinery, and integrates a motor and a hydraulic pump; wherein the motor drives the hydraulic pump to rotate under the control of the controller, and the hydraulic pump converts the mechanical energy of the motor into hydraulic energy;

[0008] A remotely configured actuator unit, which mainly includes at least one hydraulic cylinder, is installed at a working execution part of the engineering machinery and is connected to the integrated power source assembly through a flexible hydraulic pipeline to receive hydraulic energy supplied by the integrated power source assembly and convert it into mechanical energy to drive the working part;

[0009] A sensor assembly, used for monitoring and feeding back operating parameters of the integrated power source assembly and various components in the actuator unit;

[0010] A controller is used to control the operation of the motor according to the operating parameters fed back by the sensor component.

[0011] It can be understood that the present application discloses a split electrostatic hydraulic actuator for engineering machinery, including an integrated power source assembly and a remotely configured actuator unit. The hydraulic pressure generated by the integrated power source assembly is supplied to actuator units such as hydraulic cylinders through flexible hydraulic pipes. Among them, the integrated power source assembly can be installed on the rear platform of the engineering machinery, and the actuator unit can be installed separately on the working execution part of the engineering machinery, such as the boom and the dipper arm, thereby reducing the load on the working execution part. The split layout design has lower requirements for heat dissipation than the integrated design, and does not require a high-power heat dissipation system, thereby reducing system costs; the split layout design also does not require high-speed motors and high-speed hydraulic pumps, thereby avoiding the generation of loud noise.

[0012] In addition, a sensor component is provided in the split-type electrostatic-hydraulic actuator of the engineering machinery for monitoring and feeding back the working parameters of the integrated power source component and the components in the actuator unit. The controller can control the operation of the motor using a multi-loop control method based on the fed-back working parameters, which can effectively improve the dynamic performance and response speed of the system.

[0013] In an optional embodiment of the present application, the sensor assembly includes at least one of the following:

[0014] A first pressure sensor disposed on the inlet section of the flexible hydraulic pipeline, for monitoring and feeding back the inlet pressure in the inlet section;

[0015] A second pressure sensor disposed on the outlet section of the flexible hydraulic pipeline, for monitoring and feeding back the outlet pressure in the outlet section;

[0016] A displacement sensor, used for monitoring and feeding back the displacement of the piston of the hydraulic cylinder;

[0017] The rotation speed monitor is used to detect and feed back the actual rotation speed of the hydraulic pump.

[0018] In an optional embodiment of the present application, the integrated power source assembly further includes a power supply and an inverter, wherein the power supply supplies power to the inverter, and the inverter is used to drive the motor to start under the control of the controller, thereby driving the hydraulic pump to work.

[0019] In an optional embodiment of the present application, the above-mentioned split electrostatic hydraulic actuator for engineering machinery further includes a hydraulic control valve assembly for adjusting the transmission and distribution of hydraulic energy under the control of a controller.

[0020] In an optional embodiment of the present application, the integrated power source assembly also includes an oil tank, and the liquid inlet end of the hydraulic pump is connected to the oil tank through a cooler and a filter; the hydraulic control valve assembly includes an electromagnetic reversing valve, and the electromagnetic reversing valve includes an oil inlet, an oil return port, a first working oil port and a second working oil port, the oil inlet is connected to the liquid outlet end of the hydraulic pump, and the oil return port is connected to the oil tank, the first working oil port outputs liquid to the rodless chamber of the hydraulic cylinder through a first flexible hydraulic pipeline, and the second working oil port outputs liquid to the rod chamber of the hydraulic cylinder through a second flexible hydraulic pipeline.

[0021] Among them, the electromagnetic reversing valve can present multiple states under the control of the controller: 1. The neutral state, that is, the static state, the two electromagnetic valves are not energized, and the valve core is in the neutral position; at this time, the oil inlet P, the oil return port T and the first working oil port A and the second working oil port B of the actuator are not connected, the fluid cannot pass through the valve body, and the system is in a static state. 2. The first working state, when the first electromagnetic valve is energized, the valve core will move to the first side, at this time, the oil inlet P is connected to the first working oil port A, and the second working oil port B is connected to the oil return port T. The first working state has two modes: driving mode: the fluid enters from the oil inlet P and is output from the first working oil port A to the rodless chamber, pushing the hydraulic cylinder to move, while the fluid in the rod chamber flows back to the oil tank through the second working oil port B to the return oil port T; energy recovery mode: the external force pushes the hydraulic cylinder to move, the rod chamber generates negative pressure, the fluid is output from the oil tank to the rod chamber through the first one-way valve, while the fluid in the rodless chamber drives the hydraulic pump through the first working oil port A to the oil port P, at this time the hydraulic pump acts as a hydraulic motor to drive the motor to rotate and recover energy. 3. In the second working state, when the second solenoid valve is energized, the valve core will move to the second side, at this time, the oil inlet P is connected to the second working oil port B, and the first working oil port A is connected to the return oil port T. The second working state has two modes: driving mode: the fluid enters from the oil inlet P and is output from the second working oil port B to the rod chamber, pushing the hydraulic cylinder to move, while the fluid in the rodless chamber flows back to the oil tank through the first working oil port A to the return oil port T; energy recovery mode: the external force pulls the hydraulic cylinder to move, the rodless chamber generates negative pressure, the fluid is output from the oil tank to the rodless chamber through the second one-way valve, while the fluid in the rod chamber drives the hydraulic pump through the first working oil port A to the oil port P. At this time, the hydraulic pump acts as a hydraulic motor to drive the motor to rotate and recover energy. 4. Unloading state: In some special cases, if it is necessary to quickly release the pressure in the actuator or quickly return the system to the initial state, the two solenoid valves can be energized at the same time, and a special channel is designed to make the oil inlet P directly connected to the return oil port T to achieve rapid unloading.

[0022] In an optional embodiment of the present application, the hydraulic control valve assembly also includes a relief valve, a first one-way valve and a second one-way valve; the liquid inlet end of the relief valve is connected between the oil inlet and the liquid outlet end of the hydraulic pump, and the liquid outlet end of the relief valve is connected to the oil tank; a first liquid pipe is also arranged between the first working oil port and the oil tank, and the first liquid pipe is provided with the first one-way valve that only allows flow to the oil tank; a second liquid pipe is also arranged between the second working oil port and the oil tank, and the second liquid pipe is provided with the second one-way valve that only allows flow to the oil tank.

[0023] In the second aspect, the present application also discloses a control method for a split-type electrostatic hydraulic actuator for engineering machinery, which is applied to the split-type electrostatic hydraulic actuator for engineering machinery disclosed in any one of the first aspects, and the execution subject is a controller, and the method includes steps S1 to S5. Among them, S1, S2, etc. are only step identifiers, and the execution order of the method is not necessarily in the order from small to large numbers, for example, step S2 may be executed first and then step S1, and the present application does not limit it.

[0024] S1, calculating an initial preset speed of the hydraulic pump according to a target speed of the hydraulic cylinder;

[0025] S2, obtaining at least one working parameter fed back by the sensor assembly, and calculating the total compensation speed of the hydraulic pump according to the working parameter;

[0026] S3, adjusting the total compensation speed based on the initial preset speed to obtain a target speed of the hydraulic pump;

[0027] S4, obtaining the actual speed of the hydraulic pump fed back by the speed monitor in the sensor assembly, calculating the speed difference between the actual speed and the target speed, and calculating the torque adjustment value of the motor according to the speed difference;

[0028] S5, adjusting the torque of the motor according to the torque adjustment value to change the rotation speed of the hydraulic pump.

[0029] It can be understood that the present application discloses a control method for a split electrostatic hydraulic actuator of engineering machinery. In addition to calculating the initial preset speed of the hydraulic pump according to the target speed of the hydraulic cylinder, the total compensation speed is calculated according to at least one working parameter fed back by the sensor component, such as the inlet and outlet pressure difference of the flexible hydraulic pipeline, the displacement difference between the actual displacement value of the cylinder rod end of the hydraulic cylinder and the target displacement value, and the initial preset speed is compensated and adjusted. Finally, the speed of the hydraulic pump is adjusted again by the motor torque according to the speed difference between the actual speed of the hydraulic pump and the target speed. The present method controls the operation of the motor by a multi-loop control method, which can effectively improve the dynamic performance and response speed of the system.

[0030] In an optional embodiment of the present application, S2 includes the following steps:

[0031] S21: obtaining the inlet pressure in the inlet section fed back by a first pressure sensor disposed on the inlet section of the flexible hydraulic pipeline, obtaining the outlet pressure in the outlet section fed back by a second pressure sensor disposed on the outlet section of the flexible hydraulic pipeline, calculating the pressure difference between the outlet pressure and the inlet pressure, and calculating the first compensation speed of the hydraulic pump according to the pressure difference and the flow output calculated by the mathematical model through a fuzzy control algorithm;

[0032] S22: acquiring an actual displacement value of the cylinder rod end of the hydraulic cylinder fed back by a displacement sensor, calculating a displacement difference between the actual displacement value and a target displacement value, and calculating a second compensation speed of the hydraulic pump according to the displacement difference;

[0033] S23: Calculate the sum of the first compensation speed and the second compensation speed as the total compensation speed of the hydraulic pump.

[0034] In an optional embodiment of the present application, the control method of the above-mentioned engineering machinery split electrostatic hydraulic actuator further includes the following steps:

[0035] S6, dividing the flexible hydraulic pipeline into at least two sub-pipelines of equal length;

[0036] S7, calculating the output pressure of each sub-pipeline according to the volume characteristics of each sub-pipeline, and calculating the output flow rate of each sub-pipeline according to the liquid resistance and liquid sensing characteristics;

[0037] S8, obtaining the output pressure of the entire flexible hydraulic pipeline by iteratively calculating the output pressure of each sub-pipeline section; obtaining the output flow of the entire flexible hydraulic pipeline by iteratively calculating the output flow of each sub-pipeline section.

[0038] It can be understood that the purpose of steps S6 to S8 is to effectively model the flexible hydraulic pipeline using the segmented lumped parameter method based on consideration of fluid resistance, volume effect and oil inertia, so as to calculate the output pressure and output flow of the flexible hydraulic pipeline.

[0039] In an optional embodiment of the present application, the S7 includes the following steps:

[0040] S71: Calculate the output pressure of each sub-pipeline according to the following formula:

[0041]

[0042] Among them, pi represents the output pressure of the ith sub-pipeline; t represents time; Ai represents the effective cross-sectional area of ​​the ith sub-pipeline; Qi represents the flow rate of the ith sub-pipeline; xi represents the oil displacement in the ith sub-pipeline; βi represents the effective bulk modulus of the ith sub-pipeline, satisfying the following formula:

[0043]

[0044] Wherein, βfi represents the bulk modulus of the fluid in the ith sub-pipeline; βwi represents the bulk modulus of the wall of the ith sub-pipeline; ρ represents the fluid density; ωc represents the wall flexibility constant of the flexible hydraulic pipeline;

[0045] S72: Calculate the output flow of each sub-pipeline according to the following formula:

[0046]

[0047] Where Qi represents the output flow of the i-th sub-pipeline; θ i represents the inclination of the i-th sub-pipeline; kf represents the friction coefficient of the flexible hydraulic pipeline, which is determined by the Reynolds number and the relative roughness; Di represents the hydraulic diameter of the i-th sub-pipeline.

[0048] Beneficial effects:

[0049] The present application discloses a split electrostatic hydraulic actuator for construction machinery and a control method thereof. The split electrostatic hydraulic actuator for construction machinery includes an integrated power source assembly and a remotely configured actuator unit. The hydraulic pressure generated by the integrated power source assembly is supplied to actuator units such as hydraulic cylinders through flexible hydraulic pipes. In addition, the controller can control the operation of the motor according to the multi-loop control method of the working parameters fed back by the sensor assembly. The split layout design combined with the multi-loop control method realizes an operating system with good dynamic performance, fast response speed, low operating noise and good heat dissipation performance.

[0050] In order to make the above-mentioned objects, features and advantages of the present application more obvious and understandable, optional embodiments are specifically listed below and described in detail with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without paying creative work.

[0052] Figure 1 It is a structural schematic diagram of a split electrostatic hydraulic actuator for engineering machinery provided by the present application;

[0053] Figure 2 It is a flow chart of a control method of a split electrostatic hydraulic actuator for engineering machinery provided by the present application;

[0054] Figure 3 yes Figure 2 Schematic diagram of the processing process of the control method shown. DETAILED DESCRIPTION

[0055] The following will be combined with the 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. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0056] In a first aspect, the present application provides a split electrostatic hydraulic actuator for engineering machinery, which includes: an integrated power source assembly, an actuator unit, a sensor assembly and a controller.

[0057] Integrated power source components are installed on the rear platform of construction machinery, such as Figure 1 As shown, the integrated power source assembly integrates a motor 3 and a hydraulic pump 4; wherein the motor 3 drives the hydraulic pump 4 to rotate under the control of the controller 18, and the hydraulic pump 4 converts the mechanical energy of the motor 3 into hydraulic energy. Figure 1 As shown, the integrated power source assembly also includes a power supply 1 and an inverter 2. The power supply 1 supplies power to the inverter 2. The inverter 2 is used to drive the motor 3 to start under the control of the controller, thereby driving the hydraulic pump 4 to work. Figure 1 The integrated power source assembly also includes an oil tank 5 , and the liquid inlet end of the hydraulic pump 4 is connected to the oil tank 5 through a cooler and a filter 17 .

[0058] The remotely configured actuator unit mainly includes at least one hydraulic cylinder, which is installed at the working execution part of the engineering machinery and is connected to the integrated power source assembly through a flexible hydraulic pipeline to receive the hydraulic energy supplied by the integrated power source assembly and convert it into mechanical energy to drive the working parts. Figure 1 The actuator unit shown includes a hydraulic cylinder 15 , a rodless chamber of the hydraulic cylinder 15 is communicated with the integrated power source assembly through a first flexible hydraulic pipe 12 , and a rod chamber of the hydraulic cylinder 15 is communicated with the integrated power source assembly through a second flexible hydraulic pipe 14 .

[0059] The sensor assembly is used to monitor and feedback the working parameters of each component in the integrated power source assembly and the actuator unit. In an optional embodiment of the present application, Figure 1As shown, the sensor assembly includes at least one of the following: 1. A first pressure sensor 11 arranged on the inlet section of the flexible hydraulic pipeline, used to monitor and feedback the inlet pressure in the inlet section; 2. A second pressure sensor 13 arranged on the outlet section of the flexible hydraulic pipeline, used to monitor and feedback the outlet pressure in the outlet section; 3. A displacement sensor 16, used to monitor and feedback the displacement of the piston of the hydraulic cylinder; 4. A speed monitor (not shown in the figure), used to detect and feedback the actual speed of the hydraulic pump 4.

[0060] The controller is used to control the operation of the motor 3 according to the operating parameters fed back by the sensor assembly.

[0061] It can be understood that the present application discloses a split electrostatic hydraulic actuator for engineering machinery, including an integrated power source assembly and a remotely configured actuator unit. The hydraulic pressure generated by the integrated power source assembly is supplied to actuator units such as hydraulic cylinders through flexible hydraulic pipes. Among them, the integrated power source assembly can be installed on the rear platform of the engineering machinery, and the actuator unit can be installed separately on the working execution part of the engineering machinery, such as the boom and the dipper arm, thereby reducing the load on the working execution part. The split layout design has lower requirements for heat dissipation than the integrated design, and does not require a high-power heat dissipation system, thereby reducing system costs; the split layout design also does not require high-speed motors and high-speed hydraulic pumps, thereby avoiding the generation of loud noise.

[0062] In addition, a sensor component is provided in the split-type electrostatic hydraulic actuator of the engineering machinery to monitor and feedback the working parameters of each component in the integrated power source component and the actuator unit. The controller can control the operation of the motor according to the multi-loop control method based on the feedback working parameters, which can effectively improve the dynamic performance and response speed of the system.

[0063] In an optional embodiment of the present application, the above-mentioned split electrostatic hydraulic actuator for engineering machinery further includes a hydraulic control valve assembly for adjusting the transmission and distribution of hydraulic energy under the control of a controller.

[0064] like Figure 1 As shown, the hydraulic control valve assembly includes an electromagnetic reversing valve 10, which includes an oil inlet P, an oil return port T, a first working oil port A and a second working oil port B. The oil inlet P is connected to the liquid outlet end of the hydraulic pump 4, the oil return port T is connected to the oil tank 5, the first working oil port A is connected to the rodless chamber of the hydraulic cylinder 15 through the first flexible hydraulic pipe 12, and the second working oil port B is connected to the rod chamber of the hydraulic cylinder 15 through the second flexible hydraulic pipe 14.

[0065] The electromagnetic reversing valve can present a neutral state, a first working state, a second working state and a unloading state under the control of the controller.

[0066] 1. In the neutral state, i.e. the static state, both solenoid valves are not energized and the valve core is in the neutral position. At this time, the oil inlet P, the oil return port T and the first working oil port A and the second working oil port B of the actuator are not connected, the fluid cannot pass through the valve body, and the system is in a static state.

[0067] 2. In the first working state, when the first solenoid valve is energized, the valve core will move to the first side. At this time, the oil inlet P is connected to the first working oil port A, and the second working oil port B is connected to the oil return port T. The first working state has two modes: driving mode: the fluid enters from the oil inlet P and is output from the first working oil port A to the rodless chamber, pushing the hydraulic cylinder to move, while the fluid in the rod chamber flows back to the oil tank through the second working oil port B to the oil return port T; energy recovery mode: the external force pushes the hydraulic cylinder to move, the rod chamber generates negative pressure, the fluid is output from the oil tank to the rod chamber through the first one-way valve, and the fluid in the rodless chamber passes through the first working oil port A to the oil port P to drive the hydraulic pump. At this time, the hydraulic pump acts as a hydraulic motor to drive the motor to rotate and recover energy.

[0068] 3. In the second working state, when the second solenoid valve is energized, the valve core will move to the second side. At this time, the oil inlet P is connected to the second working oil port B, and the first working oil port A is connected to the oil return port T. The second working state has two modes: driving mode: the fluid enters from the oil inlet P and is output from the second working oil port B to the rod chamber, pushing the hydraulic cylinder to move, while the fluid in the rodless chamber flows back to the oil tank through the first working oil port A to the oil return port T; energy recovery mode: the external force pulls the hydraulic cylinder to move, the rodless chamber generates negative pressure, the fluid is output from the oil tank to the rodless chamber through the second one-way valve, and the fluid in the rod chamber drives the hydraulic pump through the first working oil port A to the oil port P. At this time, the hydraulic pump acts as a hydraulic motor to drive the motor to rotate and recover energy.

[0069] 4. Unloading state: In some special cases, if it is necessary to quickly release the pressure in the actuator or quickly return the system to its initial state, the two solenoid valves can be energized at the same time, and a special channel can be designed to connect the oil inlet P directly to the oil return port T to achieve rapid unloading.

[0070] In an optional embodiment of the present application, if Figure 1 As shown, the hydraulic control valve assembly also includes a relief valve 6 serving as a safety valve, a first non-return valve 8 and a second non-return valve 9; the liquid inlet end of the relief valve 6 is connected between the oil inlet P and the liquid outlet end of the hydraulic pump 4, and the liquid outlet end of the relief valve 6 is connected to the oil tank 5; a first liquid pipe is also provided between the first working oil port A and the oil tank 5, and a first non-return valve 8 is provided on the first liquid pipe, which only allows flow to the oil tank 5; a second liquid pipe is also provided between the second working oil port B and the oil tank 5, and a second non-return valve 9 is provided on the second liquid pipe, which only allows flow to the oil tank 5.

[0071] In a second aspect, the present application further discloses a control method for a split-type electrostatic hydraulic actuator for engineering machinery, which is applied to the split-type electrostatic hydraulic actuator for engineering machinery disclosed in any one of the first aspects, and the execution subject is a controller, such as Figure 2 As shown, the method includes steps S1 to S5. Among them, S1, S2, etc. are only step identifiers, and the execution order of the method is not necessarily in the order of numbers from small to large. For example, step S2 may be executed first and then step S1. This application does not limit this.

[0072] It should be understood that in the embodiments of the present invention, the controller may be a central processing unit (CPU), and the controller may also be other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field-programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0073] S1, calculating the initial preset speed of the hydraulic pump according to the target speed of the hydraulic cylinder.

[0074] like Figure 3 As shown, the controller includes a speed feedforward control unit, which controls the speed of the hydraulic cylinder according to the target speed v m , calculate the feedforward target speed ω of the hydraulic pump s , predict the disturbance in the system in advance and compensate for it, reduce the response delay of the control system and improve the system stability.

[0075] S2, obtaining at least one working parameter fed back by the sensor component, and calculating the total compensated speed of the hydraulic pump according to the working parameter.

[0076] In an optional embodiment of the present application, S2 includes the following steps:

[0077] S21: Obtain the inlet pressure in the inlet section fed back by the first pressure sensor 11 arranged on the inlet section of the flexible hydraulic pipeline, obtain the outlet pressure in the outlet section fed back by the second pressure sensor 13 arranged on the outlet section of the flexible hydraulic pipeline, calculate the pressure difference between the outlet pressure and the inlet pressure, and calculate the first compensation speed of the hydraulic pump according to the pressure difference and the flow output calculated by the mathematical model through the fuzzy control algorithm.

[0078] like Figure 3As shown, the controller includes a pressure compensation control unit. Since the hydraulic pipeline will cause pressure loss, there will be a pressure difference Δp at both ends of the hydraulic pipeline, which will affect the dynamics of the system. Therefore, the pressure compensation control unit compensates for this part of the pressure difference through fuzzy control and outputs the corresponding compensation speed ω p ,improve the trajectory tracking accuracy of the system.

[0079] S22: obtaining the actual displacement value of the cylinder rod end of the hydraulic cylinder fed back by the displacement sensor, calculating the displacement difference between the actual displacement value and the target displacement value, and calculating the second compensation speed of the hydraulic pump 4 according to the displacement difference.

[0080] like Figure 3 As shown, the controller includes a position feedback control unit. In order to improve the trajectory tracking performance of the system, the position feedback control unit is used to control the speed of the hydraulic pump. The position feedback controller adopts PID control. According to the target displacement x provided by the working target m The difference Δx between the actual displacement x and the actual displacement x is calculated, and the control speed of the output position feedback is output.

[0081] S23 : Calculate the sum of the first compensation speed and the second compensation speed as the total compensation speed of the hydraulic pump 4 .

[0082] S3, adjusting the total compensation speed based on the initial preset speed to obtain the target speed of the hydraulic pump.

[0083] S4, obtaining the actual speed of the hydraulic pump fed back by the speed monitor in the sensor assembly, calculating the speed difference between the actual speed and the target speed, and calculating the torque adjustment value of the motor according to the speed difference.

[0084] like Figure 3 As shown, the controller includes a speed feedback control unit. In order to make the actual speed of the hydraulic pump track the target speed, a speed feedback control unit is designed, which also adopts PID control. m The speed difference Δω and the actual speed ω. The output calculated motor torque T e , change the speed of the hydraulic pump.

[0085] S5, adjusting the torque of the motor according to the torque adjustment value to change the rotation speed of the hydraulic pump.

[0086] It can be understood that the present application discloses a control method for a split electrostatic hydraulic actuator of engineering machinery. In addition to calculating the initial preset speed of the hydraulic pump 4 according to the target speed of the hydraulic cylinder, the total compensation speed is calculated according to at least one working parameter fed back by the sensor component, such as the inlet and outlet pressure difference of the flexible hydraulic pipeline, the displacement difference between the actual displacement value of the cylinder rod end of the hydraulic cylinder and the target displacement value, and the initial preset speed is compensated and adjusted. Finally, according to the speed difference between the actual speed of the hydraulic pump 4 and the target speed, the speed of the hydraulic pump 4 is adjusted again by the torque of the motor 3. This method controls the operation of the motor 3 by a multi-loop control method, which can effectively improve the dynamic performance and response speed of the system.

[0087] In an optional embodiment of the present application, the control method of the above-mentioned engineering machinery split electrostatic hydraulic actuator further includes the following steps:

[0088] S6, dividing the flexible hydraulic pipeline into at least two sub-pipelines of equal length.

[0089] S7, calculating the output pressure of each sub-pipeline according to the volume characteristics of each sub-pipeline, and calculating the output flow of each sub-pipeline according to the liquid resistance and liquid sensing characteristics.

[0090] S8, obtaining the output pressure of the entire flexible hydraulic pipeline by iteratively calculating the output pressure of each sub-pipeline section; obtaining the output flow of the entire flexible hydraulic pipeline by iteratively calculating the output flow of each sub-pipeline section.

[0091] It can be understood that the purpose of steps S6 to S8 is to effectively model the flexible hydraulic pipeline using the segmented lumped parameter method based on consideration of fluid resistance, volume effect and oil inertia, so as to calculate the output pressure and output flow of the flexible hydraulic pipeline.

[0092] In an optional embodiment of the present application, S7 includes the following steps:

[0093] S71: Calculate the output pressure of each sub-pipeline according to the following formula:

[0094]

[0095] Among them, pi represents the output pressure of the ith sub-pipeline; t represents time; Ai represents the effective cross-sectional area of ​​the ith sub-pipeline; Qi represents the flow rate of the ith sub-pipeline; xi represents the oil displacement in the ith sub-pipeline; βi represents the effective bulk modulus of the ith sub-pipeline, satisfying the following formula:

[0096]

[0097] Among them, βfi represents the bulk modulus of the fluid in the ith sub-pipeline; βwi represents the bulk modulus of the wall of the ith sub-pipeline; ρ represents the fluid density; ωc represents the wall flexibility constant of the flexible hydraulic pipeline, and the specific value depends on the type of pipeline;

[0098] S72: Calculate the output flow of each sub-pipeline according to the following formula:

[0099]

[0100] Where Qi represents the output flow of the i-th sub-pipeline; θ i represents the inclination of the i-th sub-pipeline; kf represents the friction coefficient of the flexible hydraulic pipeline, which is determined by the Reynolds number and relative roughness; Di represents the hydraulic diameter of the i-th sub-pipeline.

[0101] In a third aspect, the present invention provides a computer-readable storage medium storing a computer program, wherein the computer program includes program instructions, and when the program instructions are executed by a processor, the steps of any method of the second aspect are implemented.

[0102] The computer-readable storage medium may be an internal storage unit of the terminal device of any of the aforementioned embodiments, such as a hard disk or memory of the terminal device. The computer-readable storage medium may also be an external storage device of the terminal device, such as a plug-in hard disk, a smart memory card (Smart Media Card, SMC), a secure digital (Secure Digital, SD) card, a flash card (Flash Card), etc. equipped on the terminal device. Furthermore, the computer-readable storage medium may also include both an internal storage unit of the terminal device and an external storage device. The computer-readable storage medium is used to store the computer program and other programs and data required by the terminal device. The computer-readable storage medium may also be used to temporarily store data that has been output or is to be output.

[0103] Those of ordinary skill in the art will appreciate that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in terms of function in the above description. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

[0104] In the several embodiments provided in the present application, it should be understood that the disclosed terminal device and method can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of the above units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, or it can be an electrical, mechanical or other form of connection.

[0105] The units described above as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the embodiments of the present invention.

[0106] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0107] If the above-mentioned integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention is essentially or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0108] The expressions "first", "second", "the first" or "the second" used in various embodiments of the present disclosure may modify various components regardless of order and / or importance, but these expressions do not limit the corresponding components. The above expressions are only configured for the purpose of distinguishing an element from other elements. For example, a first user device and a second user device represent different user devices, although both are user devices. For example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element without departing from the scope of the present disclosure.

[0109] When one element (e.g., a first element) is referred to as being "(operably or communicatively) coupled" or "(operably or communicatively) coupled to" or "connected to" another element (e.g., a second element), it is understood that the one element is directly connected to the other element or the one element is indirectly connected to the other element via yet another element (e.g., a third element). Conversely, it is understood that when an element (e.g., a first element) is referred to as being "directly connected" or "directly coupled" to another element (the second element), no element (e.g., a third element) is interposed between the two.

[0110] It should be noted that, in this article, the terms "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "includes a ..." does not exclude the existence of other identical elements in the process, method, article or device including the element. In addition, components, features, and elements with the same name in different embodiments of the present application may have the same meaning or different meanings, and their specific meanings need to be determined by their explanation in the specific embodiment or further combined with the context of the specific embodiment.

[0111] The above description is only an optional embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above invention concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

[0112] As used herein, the words "if" and "if" may be interpreted as "at the time of" or "when" or "in response to determining" or "in response to detecting", depending on the context. Similarly, the phrases "if it is determined" or "if (stated condition or event) is detected" may be interpreted as "when it is determined" or "in response to determining" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)", depending on the context.

[0113] The above description is only an optional embodiment of the present application and an explanation of the technical principles used. Those skilled in the art should understand that the scope of the invention involved in the present application is not limited to the technical solution formed by a specific combination of the above technical features, but should also cover other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above invention concept. For example, the above features are replaced with the technical features with similar functions disclosed in this application (but not limited to) by each other.

[0114] The above description is only an optional embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A split electrostatic hydraulic actuator for engineering machinery, characterized in that: include: An integrated power source assembly is installed on the rear platform of the engineering machinery, and integrates a motor and a hydraulic pump; wherein the motor drives the hydraulic pump to rotate under the control of the controller, and the hydraulic pump converts the mechanical energy of the motor into hydraulic energy; A remotely configured actuator unit, which mainly includes at least one hydraulic cylinder, is installed at a working execution part of the engineering machinery and is connected to the integrated power source assembly through a flexible hydraulic pipeline to receive hydraulic energy supplied by the integrated power source assembly and convert it into mechanical energy to drive the working part; A sensor assembly, used for monitoring and feeding back operating parameters of the integrated power source assembly and various components in the actuator unit; A controller is used to control the operation of the motor according to the operating parameters fed back by the sensor component.

2. The engineering machinery split electrostatic hydraulic actuator according to claim 1, characterized in that: The sensor assembly includes at least one of the following: A first pressure sensor disposed on the inlet section of the flexible hydraulic pipeline, for monitoring and feeding back the inlet pressure in the inlet section; A second pressure sensor disposed on the outlet section of the flexible hydraulic pipeline, for monitoring and feeding back the outlet pressure in the outlet section; A displacement sensor, used for monitoring and feeding back the displacement of the piston of the hydraulic cylinder; The rotation speed monitor is used to detect and feed back the actual rotation speed of the hydraulic pump.

3. The engineering machinery split electrostatic hydraulic actuator according to claim 1, characterized in that: The integrated power source assembly also includes a power supply and an inverter. The power supply supplies power to the inverter. The inverter is used to drive the motor to start under the control of the controller, thereby driving the hydraulic pump to work.

4. The engineering machinery split electrostatic hydraulic actuator according to any one of claims 1 to 3, characterized in that: It also includes a hydraulic control valve assembly for adjusting the transmission and distribution of hydraulic energy under the control of the controller.

5. The split electrostatic hydraulic actuator for construction machinery according to claim 4, The integrated power source assembly also includes an oil tank, and the liquid inlet end of the hydraulic pump is connected to the oil tank through a cooler and a filter; The hydraulic control valve assembly includes an electromagnetic reversing valve, which includes an oil inlet, an oil return port, a first working oil port and a second working oil port. The oil inlet is connected to the liquid outlet end of the hydraulic pump, the oil return port is connected to the oil tank, the first working oil port is connected to the rodless chamber of the hydraulic cylinder through a first flexible hydraulic pipeline, and the second working oil port is connected to the rod chamber of the hydraulic cylinder through a second flexible hydraulic pipeline.

6. The engineering machinery split electrostatic hydraulic actuator according to claim 5, characterized in that: The hydraulic control valve assembly further includes a relief valve, a first one-way valve and a second one-way valve; The liquid inlet end of the overflow valve is connected between the oil inlet and the liquid outlet end of the hydraulic pump, and the liquid outlet end of the overflow valve is connected to the oil tank; A first liquid pipe is also arranged between the first working oil port and the oil tank, and the first liquid pipe is provided with the first one-way valve that only allows flow to the oil tank; a second liquid pipe is also arranged between the second working oil port and the oil tank, and the second liquid pipe is provided with the second one-way valve that only allows flow to the oil tank.

7. A control method for a split electrostatic hydraulic actuator of an engineering machinery, applied to the split electrostatic hydraulic actuator of an engineering machinery as claimed in any one of claims 1 to 6, characterized in that: The following steps are involved: S1, calculating an initial preset speed of the hydraulic pump according to a target speed of the hydraulic cylinder; S2, obtaining at least one working parameter fed back by the sensor assembly, and calculating the total compensation speed of the hydraulic pump according to the working parameter; S3, adjusting the total compensation speed based on the initial preset speed to obtain a target speed of the hydraulic pump; S4, obtaining the actual speed of the hydraulic pump fed back by the speed monitor in the sensor assembly, calculating the speed difference between the actual speed and the target speed, and calculating the torque adjustment value of the motor according to the speed difference; S5, adjusting the torque of the motor according to the torque adjustment value to change the rotation speed of the hydraulic pump.

8. The control method of the split electrostatic hydraulic actuator for engineering machinery according to claim 7, characterized in that: The S2 comprises the following steps: S21: obtaining the inlet pressure in the inlet section fed back by a first pressure sensor disposed on the inlet section of the flexible hydraulic pipeline, obtaining the outlet pressure in the outlet section fed back by a second pressure sensor disposed on the outlet section of the flexible hydraulic pipeline, calculating the pressure difference between the outlet pressure and the inlet pressure, and outputting the first compensation speed of the hydraulic pump according to the pressure difference and the flow calculated by the mathematical model through a fuzzy control algorithm; S22: acquiring an actual displacement value of the cylinder rod end of the hydraulic cylinder fed back by a displacement sensor, calculating a displacement difference between the actual displacement value and a target displacement value, and calculating a second compensation speed of the hydraulic pump according to the displacement difference; S23: Calculate the sum of the first compensation speed and the second compensation speed as the total compensation speed of the hydraulic pump.

9. The control method of the split electrostatic hydraulic actuator for engineering machinery according to claim 7, characterized in that: The following steps are also included: S6, dividing the flexible hydraulic pipeline into at least two sub-pipelines of equal length; S7, calculating the output pressure of each sub-pipeline according to the volume characteristics of each sub-pipeline, and calculating the output flow rate of each sub-pipeline according to the liquid resistance and liquid sensing characteristics; S8, obtaining the output pressure of the entire flexible hydraulic pipeline by iteratively calculating the output pressure of each sub-pipeline section; obtaining the output flow of the entire flexible hydraulic pipeline by iteratively calculating the output flow of each sub-pipeline section.

10. The control method of the split electrostatic hydraulic actuator for engineering machinery according to claim 9, characterized in that: The S7 comprises the following steps: S71: Calculate the output pressure of each sub-pipeline according to the following formula: Among them, pi represents the output pressure of the ith sub-pipeline; t represents time; Ai represents the effective cross-sectional area of ​​the ith sub-pipeline; Qi represents the flow rate of the ith sub-pipeline; xi represents the oil displacement in the ith sub-pipeline; βi represents the effective bulk modulus of the ith sub-pipeline, satisfying the following formula: Wherein, βfi represents the bulk modulus of the fluid in the ith sub-pipeline; βwi represents the bulk modulus of the wall of the ith sub-pipeline; ρ represents the fluid density; ωc represents the wall flexibility constant of the flexible hydraulic pipeline; S72: Calculate the output flow of each sub-pipeline according to the following formula: Where Qi represents the output flow of the i-th sub-pipeline; θ i represents the inclination of the i-th sub-pipeline; kf represents the friction coefficient of the flexible hydraulic pipeline, which is determined by the Reynolds number and the relative roughness; Di represents the hydraulic diameter of the i-th sub-pipeline.

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