Speed optimization method and system for electro-hydrostatic driving operation system

Abstract

The invention discloses a speed optimization method and system for an electro-hydrostatic driving operation system. The speed optimization method and system are used for optimizing the displacement speed of a hydraulic cylinder. The method comprises the following steps: calculating an optimal control input curve of a minimum value of a Hamilton function of a system; calculating an optimal speed trajectory curve of the hydraulic cylinder according to the curve; and the optimal control input curve serves as feedforward input, feedback closed-loop control of the current moving speed of the hydraulic cylinder is combined, a control signal is output to a motor controller, and the hydraulic cylinder operates according to the optimal speed track. The method comprises the steps of receiving feedback of a pressure sensor, calculating starting end and terminal conditions of a system, constructing a state equation and a performance functional, designing a Hamilton function, and calculating optimal control input based on a regular equation. According to the method, the limitation that the energy efficiency of the electro-hydrostatic driving operation system is limited by the operation behavior of a driver is broken through, global optimization of the energy efficiency of the operation system is achieved, and the overall performance and the energy saving level of engineering machinery are improved.

Description

Technical Field

[0001] The present application relates to the technical field of engineering machinery, and in particular to a speed optimization method and system for an electrostatic-hydraulic drive operating system. Background Art

[0002] With the accelerating electrification of construction machinery, distributed electrostatic hydraulic systems are gaining increasing attention and application due to their unique advantages. These systems are commonly used in various types of construction machinery requiring precise hydraulic power output, such as excavators and loaders, and can meet the power requirements of hydraulic actuators in various operating scenarios.

[0003] The distributed electro-hydrostatic drive hydraulic operating system primarily consists of key components such as the motor, hydraulic pump, hydraulic cylinder, and energy recovery device. Its operating principle is as follows: The motor independently controls the speed of the hydraulic pump, delivering hydraulic oil at varying flow rates and pressures. This oil directly acts on the hydraulic cylinder, achieving various hydraulic actuator movements. Simultaneously, the energy recovery device recycles some of the energy in the hydraulic system for reuse. Compared to traditional centralized throttling control operating systems, this system eliminates the throttling control valve, avoiding energy loss during the throttling process and effectively overcoming the bottleneck of low efficiency in centralized throttling control.

[0004] However, the current level of intelligence in electric construction machinery is limited, and during operation, the machine's operating efficiency is highly dependent on the operator's experience. Due to the lack of scientific speed planning and control strategies, the hydraulic actuator's speed trajectory is not optimized, resulting in inefficient energy utilization in the operation system. In actual operation, the operator has difficulty accurately adjusting the hydraulic actuator speed in real time according to different working conditions, resulting in low system energy efficiency. This prevents the full energy-saving potential of the distributed electrostatic hydraulic drive hydraulic operation system from being fully utilized, limiting the overall performance improvement and energy conservation of the construction machinery. Summary of the Invention

[0005] The purpose of this application is to provide a speed optimization method and system for an electrostatic hydraulic drive operating system, which can improve the above-mentioned problems.

[0006] The embodiment of the present application is implemented as follows: In the first aspect, the present application provides a speed optimization method for an electrostatic-hydraulic drive operating system, which is used to optimize the displacement speed of the hydraulic cylinder in the electrostatic-hydraulic drive operating system, and includes steps S1 to S3, wherein S1, S2, etc. are only step identifiers, and the execution order of the method is not necessarily in ascending order of numbers. For example, step S2 may be executed first and then step S1. This application does not impose any restrictions.

[0007] S1, calculating and obtaining an optimal control input curve that minimizes the Hamiltonian function of the electrostatic hydraulic drive operating system; S2, calculating an optimal speed trajectory curve of the hydraulic cylinder in the system according to the optimal control input curve; S3, using the optimal control input curve as a feedforward input, combined with the feedback closed-loop control of the current moving speed of the hydraulic cylinder, outputs a control signal to the motor controller of the electrostatic hydraulic drive operating system, so that the hydraulic cylinder operates according to the optimal speed trajectory curve.

[0008] It can be understood that the speed optimization method of the electro-hydrostatic drive operating system provided in this application adopts the minimum principle to obtain the optimal speed trajectory and optimal motor speed of the hydraulic cylinder under the typical operating conditions of engineering machinery, and uses them as the reference input and feedforward input of the speed controller respectively. Combined with speed feedback closed-loop control, it ensures that the hydraulic cylinder operates according to the optimal speed trajectory. On the basis of eliminating the throttling loss of the valve control system, it breaks through the limitation that the energy efficiency of the electro-hydrostatic drive operating system is limited by the driver's operating behavior, so that the energy efficiency of the operating system can achieve global optimization under the typical operating conditions of engineering machinery.

[0009] In an optional embodiment of the present application, S1 includes steps S11 to S14, wherein S11, S12, etc. are merely step identifiers, and the execution order of the method is not necessarily in ascending order of numbers. For example, step S12 may be executed first and then step S11. This application does not impose any restrictions.

[0010] S11, calculating the system initial conditions according to the full bucket rate at the initial moment of system operation, and determining the terminal constraint conditions at the end moment of system operation according to the input expected displacement parameters of the hydraulic cylinder.

[0011] S12, construct the system state equation and the performance functional of the system energy consumption.

[0012] S13, designing a system Hamiltonian function according to the system state equation and the performance functional, and obtaining a canonical equation of the costate vector based on the system Hamiltonian function.

[0013] S14, calculating the new co-state vector corresponding to each moment based on the canonical equation, and then calculating the optimal control input when the Hamiltonian function takes a minimum value according to the new co-state vector, to obtain the optimal control input curve with respect to time change.

[0014] In an optional embodiment of the present application, the S11 includes: receiving the rod chamber pressure value and the rodless chamber pressure value of the hydraulic cylinder in the initial state fed back by the pressure sensor, and calculating the full bucket rate at the initial moment of system operation, and calculating the initial displacement of the piston in the hydraulic cylinder according to the full bucket rate as the system starting condition; receiving the expected displacement and expected movement time of the piston in the hydraulic cylinder, and calculating the terminal displacement of the piston in the hydraulic cylinder as the system terminal constraint condition In an optional embodiment of the present application, the S12 includes the following steps S121 to S122.

[0015] S121. Construct the system state equation according to the following formula: ; in, represent The displacement value of the piston in the hydraulic cylinder at the moment, represent The first derivative with respect to time, i.e., the displacement velocity of the piston in the hydraulic cylinder; Represents the hydraulic pump motor displacement in the system; Represents the control input of the system, that is, the output speed of the servo motor in the system; Represents the hydraulic pump motor output flow loss, which is about the system state variable and control inputs function; Represents the effective area of ​​the rodless chamber of the hydraulic cylinder.

[0016] S122. Construct a performance functional for system energy consumption according to the following formula: ; Represents the initial time of system operation; Represents the end time of system operation; is the Lagrangian function, which contains the relevant information of the system energy consumption. ; represents the co-state vector; Represents the pressure difference between the first oil port and the second oil port of the hydraulic pump motor, which is related to the system state variable function; Represents the hydraulic pump motor input torque loss, which is related to the system state variable and control inputs function; Represents the servo motor output power loss, which is about the system state variable and control inputs function.

[0017] In an optional embodiment of the present application, the S13 includes: The system Hamiltonian function is designed according to the following formula : ; The canonical equation of the co-state vector is obtained according to the following formula: In an optional embodiment of the present application, the S14 includes the following steps S141 to S143.

[0018] S141, using a grid search method to select an initial value of a co-state vector, and using the system starting conditions to calculate the optimal control input when the Hamiltonian function takes a minimum value at the initial moment of the system operation.

[0019] S142, from the initial moment of the system operation onwards, a new co-state vector is calculated based on the canonical equation at each moment, and based on the system state equation corresponding to the current moment, the optimal control input that makes the Hamiltonian function take a minimum value at the current moment is calculated according to the new co-state vector, until the terminal moment of the system operation is reached and the terminal constraint condition is satisfied.

[0020] S143 , drawing an optimal control input curve with respect to time variation according to the optimal control input between the initial time of the system operation and the final time of the system operation.

[0021] In an optional embodiment of the present application, calculating the optimal control input that makes the Hamiltonian function take a minimum value at the current moment includes: The Hamiltonian function at the current moment is obtained according to the following formula About control input Find the partial derivatives: ; Set the partial derivative equal to zero and solve for the optimal control input according to the following formula : .

[0022] In an optional embodiment of the present application, S2 includes: substituting the optimal control input curve into the system state equation to calculate the optimal speed trajectory curve of the hydraulic cylinder in the system.

[0023] In the second aspect, the present application discloses a speed optimization system for an electrostatic-hydraulic drive operating system, which is used to optimize the displacement speed of the hydraulic cylinder in the electrostatic-hydraulic drive operating system. The electrostatic-hydraulic drive operating system includes a motor controller, a servo motor, a hydraulic pump motor, a hydraulic cylinder, a first electromagnetic switch valve, and a second electromagnetic switch valve; the motor controller is used to control the output speed of the servo motor, and the servo motor is used to drive the hydraulic pump motor to operate. The first oil port of the hydraulic pump motor is connected to the rod cavity of the hydraulic cylinder through the first electromagnetic switch valve, and the second oil port of the hydraulic pump motor is connected to the rodless cavity of the hydraulic cylinder through the second electromagnetic switch valve. The above-mentioned speed optimization system includes a speed sensor and a speed control device, the speed sensor is used to feedback the displacement speed of the hydraulic cylinder, the speed control device is electrically connected to the speed sensor and the motor controller respectively, and the speed control device is used to execute the method described in any one of the first aspects.

[0024] In an optional embodiment of the present application, the speed optimization system further includes a first pressure sensor and a second pressure sensor; the first pressure sensor is used to feedback the pressure value of the rod cavity, and the second pressure sensor is used to feedback the pressure value of the rodless cavity.

[0025] In an optional embodiment of the present application, the speed control device includes a full bucket rate calculation unit, a speed trajectory planning unit and a speed control unit; the full bucket rate calculation unit is electrically connected to the first pressure sensor and the second pressure sensor, and is used to calculate the full bucket rate at the initial moment of system operation based on the rod chamber pressure value of the hydraulic cylinder in the initial state fed back by the first pressure sensor and the rodless chamber pressure value of the hydraulic cylinder in the initial state fed back by the second pressure sensor; the speed trajectory planning unit is electrically connected to the full bucket rate calculation unit, and is used to calculate the optimal control input curve that makes the system Hamiltonian function of the electrostatic drive operating system take a minimum value, and calculate the optimal speed trajectory curve of the hydraulic cylinder in the system based on the optimal control input curve; the speed control unit is electrically connected to the speed trajectory planning unit, and is used to use the optimal control input curve as a feedforward input, combined with the feedback closed-loop control of the current moving speed of the hydraulic cylinder, to output a control signal to the motor controller so that the hydraulic cylinder operates according to the optimal speed trajectory curve.

[0026] In an optional embodiment of the present application, the electrostatic hydraulic drive operating system also includes a first safety valve, a second safety valve, a low-pressure accumulator, a first hydraulically controlled one-way valve, a second hydraulically controlled one-way valve, a third safety valve and a fourth safety valve; the inlet of the first hydraulically controlled one-way valve is connected to the port connecting the first electromagnetic switch valve and the rod chamber, the outlet of the first hydraulically controlled one-way valve is connected to the outlet of the second hydraulically controlled one-way valve, the inlet of the second hydraulically controlled one-way valve is connected to the port connecting the second electromagnetic switch valve and the rodless chamber, the low-pressure accumulator is connected between the first hydraulically controlled one-way valve and the second hydraulically controlled one-way valve, and the low-pressure accumulator replenishes hydraulic oil to the first oil port through the first hydraulically controlled one-way valve; the first safety valve is used to limit the maximum pressure between the first oil port and the first electromagnetic switch valve, and the second safety valve is used to limit the maximum pressure between the second oil port and the second electromagnetic switch valve; the third safety valve is used to limit the maximum pressure between the first electromagnetic switch valve and the rod chamber, and the fourth safety valve is used to limit the maximum pressure between the second electromagnetic switch valve and the rodless chamber. Beneficial effects

[0027] The present application proposes a speed optimization method for an electrostatic-hydraulic drive operating system, which is used to optimize the displacement speed of a hydraulic cylinder. The method includes: calculating the optimal control input curve for the minimum value of the system Hamiltonian function; calculating the optimal speed trajectory curve of the hydraulic cylinder based on this curve; using the optimal control input curve as a feedforward input, combined with the feedback closed-loop control of the current moving speed of the hydraulic cylinder, outputting a control signal to the motor controller so that the hydraulic cylinder runs according to the optimal speed trajectory. The method receives feedback from the pressure sensor, calculates the system's initial and terminal conditions, constructs the state equation and performance functional, designs the Hamiltonian function, and calculates the optimal control input based on the canonical equation. This method breaks through the limitation that the energy efficiency of the electrostatic-hydraulic drive operating system is limited by the driver's operating behavior, achieves the global optimization of the energy efficiency of the operating system, and improves the overall performance and energy saving level of engineering machinery.

[0028] The present application proposes a speed optimization system for an electrostatic-hydraulic driven operating system, which is used to optimize the displacement speed of a hydraulic cylinder. The system includes a speed sensor and a speed control device. The speed sensor feeds back the displacement speed of the hydraulic cylinder, and the speed control device executes a speed optimization method. The system also includes a pressure sensor for feeding back the pressure values ​​of the rod chamber and the rodless chamber of the hydraulic cylinder. The speed control device includes a full bucket rate calculation unit, a speed trajectory planning unit, and a speed control unit, which are respectively responsible for calculating the full bucket rate, the optimal control input curve, and the optimal speed trajectory curve, and outputting a control signal to enable the hydraulic cylinder to operate according to the optimal trajectory. By scientifically planning the speed trajectory of the hydraulic cylinder, the system significantly improves the energy efficiency of the operating system, reduces energy consumption, and improves the overall performance of the engineering machinery. At the same time, it reduces the impact of the driver's operation on the operating efficiency, improves the operating accuracy and stability, and provides strong support for the intelligent development of engineering machinery.

[0029] In order to make the above-mentioned objectives, features and advantages of the present application more obvious and easy to understand, optional embodiments are specifically listed below and described in detail with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. 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 relevant drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 This is a schematic flow chart of the steps of a speed optimization method for an electrostatic hydraulic drive operating system provided by the present application; Figure 2 This is a schematic diagram of the principle of a speed optimization method for an electrostatic hydraulic drive operating system provided by the present application; Figure 3 This is a schematic diagram of a speed optimization system for an electrostatic-hydraulic driven operating system provided in this application. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0033] First, the present application provides a speed optimization method for an electrostatic-hydraulic drive operating system, which is used to optimize the displacement speed of the hydraulic cylinder 18 in the electrostatic-hydraulic drive operating system, including steps S1 to S3, wherein S1, S2, etc. are only step identifiers, and the execution order of the method is not necessarily in ascending order of numbers. For example, step S2 may be executed first and then step S1. This application does not impose any restrictions.

[0034] like Figure 3 As shown, the electro-hydrostatic drive operating system includes a motor controller 4, a servo motor 5, a hydraulic pump motor 6, a hydraulic cylinder 18, a first solenoid switch valve 11, and a second solenoid switch valve 12. The motor controller 4 is used to control the output speed of the servo motor 5, which is used to drive the hydraulic pump motor 6. The first oil port of the hydraulic pump motor 6 is connected to the rod chamber of the hydraulic cylinder 18 through the first solenoid switch valve 11, and the second oil port of the hydraulic pump motor 6 is connected to the rodless chamber of the hydraulic cylinder 18 through the second solenoid switch valve 12. The electro-hydrostatic drive operating system also includes a first safety valve 9, a second safety valve 10, a low-pressure accumulator 13, a first hydraulically controlled one-way valve 14, a second hydraulically controlled one-way valve 15, a third safety valve 16, and a fourth safety valve 17. The inlet of the first hydraulically controlled one-way valve 14 is connected to the port of the first solenoid switch valve 11 connected to the rod chamber, the outlet of the first hydraulically controlled one-way valve 14 is connected to the outlet of the second hydraulically controlled one-way valve 15, the inlet of the second hydraulically controlled one-way valve 15 is connected to the port of the second solenoid switch valve 12 connected to the rodless chamber, the low-pressure accumulator 13 is connected between the first hydraulically controlled one-way valve 14 and the second hydraulically controlled one-way valve 15, and the low-pressure accumulator 13 replenishes hydraulic oil to the first oil port through the first hydraulically controlled one-way valve 14; the first safety valve 9 is used to limit the maximum pressure between the first oil port and the first solenoid switch valve 11, and the second safety valve 10 is used to limit the maximum pressure between the second oil port and the second solenoid switch valve 12; the third safety valve 16 is used to limit the maximum pressure between the first solenoid switch valve 11 and the rod chamber, and the fourth safety valve 17 is used to limit the maximum pressure between the second solenoid switch valve 12 and the rodless chamber.

[0035] Taking the operating condition where hydraulic cylinder 18 extends and the load force and load velocity are opposite, the operating principle of the electrostatic drive working system is described as follows: In this operating condition, the hydraulic pump-motor 6 operates in hydraulic pump mode. The first port (above the hydraulic pump-motor 6 in the figure) draws hydraulic oil, and the second port (below the hydraulic pump-motor 6 in the figure) discharges hydraulic oil. The first and second solenoid valves 11, 12 are open, and the low-pressure accumulator 13 replenishes hydraulic oil to the first port of the hydraulic pump-motor 6 through the first hydraulically controlled check valve 14. The first safety valve 9 limits the maximum pressure between the first port of the hydraulic pump-motor 6 and the first solenoid valve 11. The second safety valve 10 limits the maximum pressure between the second port of the hydraulic pump-motor 6 and the second solenoid valve 12. The third safety valve 16 limits the maximum pressure between the first solenoid valve 11 and the rod chamber of the hydraulic cylinder 18. The fourth safety valve 17 limits the maximum pressure between the second solenoid valve 12 and the rodless chamber of the hydraulic cylinder 18. The first and second solenoid valves 11, 12 are used to implement the load-holding function when the working system is stopped.

[0036] S1, calculate and obtain the optimal control input curve that makes the system Hamiltonian function of the electrostatic hydraulic drive operating system take the minimum value.

[0037] S2, calculating the optimal speed trajectory curve of the hydraulic cylinder in the system based on the optimal control input curve. In an optional embodiment of the present application, S2 includes: substituting the optimal control input curve into the system state equation to calculate the optimal speed trajectory curve of the hydraulic cylinder in the system.

[0038] S3, using the optimal control input curve as the feedforward input, combined with the feedback closed-loop control of the current moving speed of the hydraulic cylinder, outputs a control signal to the motor controller of the electrostatic hydraulic drive operation system, so that the hydraulic cylinder operates according to the optimal speed trajectory curve.

[0039] It can be understood that the speed optimization method of the electrostatic hydraulic drive operating system provided in this application is as follows: Figure 2 As shown in the figure, the minimum principle is used to obtain the optimal speed trajectory and optimal motor speed of the hydraulic cylinder under typical operating conditions of construction machinery. These are used as the reference input and feedforward input of the speed controller, respectively. Combined with speed feedback closed-loop control, the hydraulic cylinder is guaranteed to operate according to the optimal speed trajectory. On the basis of eliminating the throttling loss of the valve control system, the limitation that the energy efficiency of the electrostatic-hydraulic drive operating system is limited by the driver's operating behavior is broken through, so that the energy efficiency of the operating system can achieve global optimization under typical operating conditions of construction machinery.

[0040] In an optional embodiment of the present application, reference Figure 1As shown, S1 includes steps S11 to S14, where S11, S12, 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 S12 may be executed first and then step S11. This application does not impose any restrictions.

[0041] S11, calculating the system initial conditions according to the full bucket rate at the initial moment of system operation, and determining the terminal constraint conditions at the end moment of system operation according to the input expected displacement parameters of the hydraulic cylinder.

[0042] In an optional embodiment of the present application, S11 includes: receiving the rod chamber pressure value and the rodless chamber pressure value of the hydraulic cylinder in the initial state fed back by the pressure sensor, and calculating the full bucket rate at the initial moment of system operation, and calculating the initial displacement of the piston in the hydraulic cylinder based on the full bucket rate as the system starting condition; receiving the expected displacement and expected movement time of the piston in the hydraulic cylinder, and calculating the terminal displacement of the piston in the hydraulic cylinder as the system terminal constraint condition.

[0043] S12, construct the system state equation and the performance functional of the system energy consumption.

[0044] In an optional embodiment of the present application, the system state equation is constructed according to the following formula: ;in, represent The displacement value of the piston in the hydraulic cylinder 18 at the moment, represent The first derivative with respect to time, i.e. the displacement velocity of the piston in the hydraulic cylinder 18; Represents the displacement of the hydraulic pump motor 6 in the system; represents the control input of the system, i.e., the output speed of the servo motor 5 in the system; Represents the output flow loss of the hydraulic pump motor 6, which is related to the system state variable and control inputs function; Represents the effective area of ​​the rodless chamber of the hydraulic cylinder 18.

[0045] In an optional embodiment of the present application, a performance functional of system energy consumption is constructed according to the following formula: ; Represents the initial time of system operation; Represents the end time of system operation; is the Lagrangian function, which contains the relevant information of the system energy consumption. ; represents the co-state vector; Represents the pressure difference between the first oil port and the second oil port of the hydraulic pump motor 6, which is related to the system state variable function; Represents the input torque loss of the hydraulic pump motor 6, which is related to the system state variable and control inputs function; Represents the output power loss of servo motor 5, which is related to the system state variable and control inputs function.

[0046] S13, the system Hamiltonian function is designed according to the system state equation and performance functional, and the canonical equation of the co-state vector is obtained based on the system Hamiltonian function.

[0047] In an optional embodiment of the present application, the system Hamiltonian function is designed according to the following formula: : ; The canonical equation of the co-state vector is obtained according to the following formula: .

[0048] S14, based on the canonical equation, the new co-state vector corresponding to each moment is calculated, and then the optimal control input when the Hamiltonian function takes the minimum value is calculated according to the new co-state vector, and the optimal control input curve with respect to time change is obtained.

[0049] In the optional embodiment of this application, continue to refer to Figure 1 As shown, S14 includes the following steps S141 to S143.

[0050] S141, using a grid search method to select an initial value of the co-state vector, and using the system initial conditions to calculate the optimal control input when the Hamiltonian function takes a minimum value at the initial moment of system operation.

[0051] S142, from the initial moment of system operation onwards, calculate the new co-state vector based on the canonical equation at each moment, and based on the system state equation corresponding to the current moment, calculate the optimal control input that makes the Hamiltonian function take the minimum value at the current moment according to the new co-state vector, until the terminal moment of system operation is reached and the terminal constraint conditions are met.

[0052] S143, drawing an optimal control input curve with respect to time variation based on the optimal control input between the initial time of the system operation and the final time of the system operation.

[0053] In an optional embodiment of the present application, calculating the optimal control input that makes the Hamiltonian function take a minimum value at the current moment includes: According to the following formula, the Hamiltonian function at the current moment is obtained About control input Find the partial derivatives: ; According to the following formula, let the partial derivative equal to zero and solve for the optimal control input : .

[0054] Second, as Figure 3 As shown, the present application discloses a speed optimization system for an electrostatic-hydraulic drive operating system, which is used to optimize the displacement speed of the hydraulic cylinder 18 in the electrostatic-hydraulic drive operating system. The electrostatic-hydraulic drive operating system includes a motor controller 4, a servo motor 5, a hydraulic pump motor 6, a hydraulic cylinder 18, a first electromagnetic switch valve 11, and a second electromagnetic switch valve 12; the motor controller 4 is used to control the output speed of the servo motor 5, and the servo motor 5 is used to drive the hydraulic pump motor 6 to operate. The first oil port of the hydraulic pump motor 6 is connected to the rod cavity of the hydraulic cylinder 18 through the first electromagnetic switch valve 11, and the second oil port of the hydraulic pump motor 6 is connected to the rodless cavity of the hydraulic cylinder 18 through the second electromagnetic switch valve 12. The above-mentioned speed optimization system includes a speed sensor and a speed control device. The speed sensor is used to feedback the displacement speed of the hydraulic cylinder 18. The speed control device is electrically connected to the speed sensor and the motor controller 4 respectively. The speed control device is used to execute any method as in the first aspect.

[0055] In an optional embodiment of the present application, Figure 3 As shown, the speed optimization system further includes a first pressure sensor 7 and a second pressure sensor 8; the first pressure sensor 7 is used to feed back the pressure value of the rod cavity, and the second pressure sensor 8 is used to feed back the pressure value of the rodless cavity.

[0056] In an optional embodiment of the present application, Figure 3 As shown, the speed control device includes a full bucket rate calculation unit 1, a speed trajectory planning unit 2 and a speed control unit 3; the full bucket rate calculation unit 1 is electrically connected to the first pressure sensor 7 and the second pressure sensor 8, and is used to calculate the full bucket rate at the initial moment of system operation based on the rod chamber pressure value of the hydraulic cylinder 18 in the initial state fed back by the first pressure sensor 7 and the rodless chamber pressure value of the hydraulic cylinder 18 in the initial state fed back by the second pressure sensor 8; the speed trajectory planning unit 2 is electrically connected to the full bucket rate calculation unit 1, and is used to calculate the optimal control input curve that makes the system Hamiltonian function of the electrostatic drive operating system take a minimum value, and calculate the optimal speed trajectory curve of the hydraulic cylinder 18 in the system based on the optimal control input curve; the speed control unit 3 is electrically connected to the speed trajectory planning unit 2, and is used to use the optimal control input curve as a feedforward input, combined with the feedback closed-loop control of the current moving speed of the hydraulic cylinder 18, to output a control signal to the motor controller 4, so that the hydraulic cylinder 18 operates according to the optimal speed trajectory curve.

[0057] In an optional embodiment of the present application, the electrostatic hydraulic drive operating system also includes a first safety valve 9, a second safety valve 10, a low-pressure accumulator 13, a first hydraulically controlled one-way valve 14, a second hydraulically controlled one-way valve 15, a third safety valve 16 and a fourth safety valve 17. The inlet of the first hydraulically controlled one-way valve 14 is connected to the port of the first solenoid switch valve 11 connected to the rod chamber, the outlet of the first hydraulically controlled one-way valve 14 is connected to the outlet of the second hydraulically controlled one-way valve 15, the inlet of the second hydraulically controlled one-way valve 15 is connected to the port of the second solenoid switch valve 12 connected to the rodless chamber, the low-pressure accumulator 13 is connected between the first hydraulically controlled one-way valve 14 and the second hydraulically controlled one-way valve 15, and the low-pressure accumulator 13 replenishes hydraulic oil to the first oil port through the first hydraulically controlled one-way valve 14; the first safety valve 9 is used to limit the maximum pressure between the first oil port and the first solenoid switch valve 11, and the second safety valve 10 is used to limit the maximum pressure between the second oil port and the second solenoid switch valve 12; the third safety valve 16 is used to limit the maximum pressure between the first solenoid switch valve 11 and the rod chamber, and the fourth safety valve 17 is used to limit the maximum pressure between the second solenoid switch valve 12 and the rodless chamber.

[0058] The terms "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 terms do not limit the corresponding components. The above terms are configured solely 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, even though 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.

[0059] When one element (for example, a first element) is referred to as being “(operably or communicably) coupled” or “(operably or communicably) coupled to” or “connected to” another element (for example, a second element), it should be understood that the one element is directly connected to the other element or that the one element is indirectly connected to the other element via yet another element (for example, a third element). Conversely, it should be understood that when an element (for example, a first element) is referred to as being “directly connected” or “directly coupled” to another element (the second element), there is no element (for example, a third element) interposed therebetween.

[0060] It should be noted that, in this document, the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the sentence "comprising a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising 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.

[0061] The above description is merely an optional embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but should also encompass other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the above-mentioned inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

[0062] 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 the determination" or "when detecting (stated condition or event)" or "in response to detecting (stated condition or event)," depending on the context.

[0063] The above description is merely an optional embodiment of the present application and an illustration of the technical principles employed. Those skilled in the art should understand that the scope of the invention involved in this application is not limited to the technical solutions formed by a specific combination of the above-mentioned technical features, but should also encompass other technical solutions formed by any combination of the above-mentioned technical features or their equivalents without departing from the above-mentioned inventive concept. For example, a technical solution formed by replacing the above-mentioned features with (but not limited to) technical features with similar functions disclosed in this application.

[0064] The above description is merely an optional embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A speed optimization method for an electrostatic-hydraulic driven operating system, for optimizing the displacement speed of a hydraulic cylinder in the electrostatic-hydraulic driven operating system, characterized in that: The following steps are involved: S1, calculating and obtaining an optimal control input curve that minimizes the Hamiltonian function of the electrostatic hydraulic drive operating system; S2, calculating an optimal speed trajectory curve of the hydraulic cylinder in the system according to the optimal control input curve; S3, using the optimal control input curve as a feedforward input, combined with the feedback closed-loop control of the current moving speed of the hydraulic cylinder, outputs a control signal to the motor controller of the electrostatic hydraulic drive operating system, so that the hydraulic cylinder operates according to the optimal speed trajectory curve.

2. The speed optimization method of the electrostatic hydraulic drive operating system according to claim 1, characterized in that: Said S1 comprises the following steps: S11, calculating the system initial conditions based on the full bucket rate at the initial moment of system operation, and determining the terminal constraint conditions at the end moment of system operation based on the input expected displacement parameters of the hydraulic cylinder; S12, construct the system state equation and the performance functional of the system energy consumption; S13, designing a system Hamiltonian function according to the system state equation and the performance functional, and obtaining a canonical equation of the co-state vector based on the system Hamiltonian function; S14, calculating the new co-state vector corresponding to each moment based on the canonical equation, and then calculating the optimal control input when the Hamiltonian function takes a minimum value according to the new co-state vector, to obtain the optimal control input curve with respect to time change.

3. The speed optimization method of the electrostatic hydraulic drive operating system according to claim 2, characterized in that: The S11 includes the following steps: S111, receiving the rod chamber pressure value and the rodless chamber pressure value of the hydraulic cylinder in the initial state fed back by the pressure sensor, calculating the fullness ratio at the initial moment of system operation, and calculating the initial displacement of the piston in the hydraulic cylinder based on the fullness ratio as the system starting condition; S112, receiving the expected displacement and expected movement duration of the piston in the hydraulic cylinder, and calculating the terminal displacement of the piston in the hydraulic cylinder as a system terminal constraint condition.

4. The speed optimization method of the electrostatic hydraulic drive operating system according to claim 3, characterized in that: The S12 includes the following steps: S121, construct the system state equation according to the following formula: in, represent The displacement value of the piston in the hydraulic cylinder at the moment, represent The first derivative with respect to time, i.e., the displacement velocity of the piston in the hydraulic cylinder; Represents the hydraulic pump motor displacement in the system; Represents the control input of the system, that is, the output speed of the servo motor in the system; Represents the hydraulic pump motor output flow loss, which is about the system state variable and control inputs function; represents the effective area of ​​the rodless chamber of the hydraulic cylinder; S122, construct the performance functional of the system energy consumption according to the following formula: ； Represents the initial time of system operation; Represents the end time of system operation; is the Lagrangian function, which contains the relevant information of the system energy consumption. ; represents the co-state vector; The pressure difference between the first oil port and the second oil port of the hydraulic pump motor is related to the system state variable function; Represents the hydraulic pump motor input torque loss, which is related to the system state variable and control inputs function; Represents the servo motor output power loss, which is about the system state variable and control inputs function.

5. The speed optimization method of the electrostatic hydraulic drive operating system according to claim 4, characterized in that: The S13 includes: The system Hamiltonian function is designed according to the following formula : ； The canonical equation of the co-state vector is obtained according to the following formula:

6. The speed optimization method of the electrostatic hydraulic drive operating system according to claim 5, characterized in that: The S14 includes the following steps: S141, selecting an initial value of the co-state vector using a grid search method, and calculating the optimal control input when the Hamiltonian function takes a minimum value at the initial moment of the system operation using the system starting conditions; S142, from the initial moment of the system operation onward, calculating a new co-state vector based on the canonical equation at each moment, and calculating, based on the system state equation corresponding to the current moment, the optimal control input that minimizes the Hamiltonian function at the current moment according to the new co-state vector, until the system operation ends and the terminal constraint is satisfied; S143 , drawing an optimal control input curve with respect to time variation according to the optimal control input between the initial time of the system operation and the final time of the system operation.

7. The speed optimization method of the electrostatic hydraulic drive operating system according to claim 6, characterized in that: The calculating of the optimal control input that makes the Hamiltonian function take a minimum value at the current moment includes: The Hamiltonian function at the current moment is obtained according to the following formula On control input Find the partial derivatives: ； According to the following formula, let the partial derivative equal to zero and solve for the optimal control input : 。 8. A speed optimization system for an electrostatic-hydraulic drive operating system, used for optimizing the displacement speed of a hydraulic cylinder in the electrostatic-hydraulic drive operating system, wherein the electrostatic-hydraulic drive operating system comprises a motor controller, a servo motor, a hydraulic pump motor, a hydraulic cylinder, a first electromagnetic switch valve, and a second electromagnetic switch valve; the motor controller is used to control the output speed of the servo motor, and the servo motor is used to drive the hydraulic pump motor to operate, the first oil port of the hydraulic pump motor is connected to the rod cavity of the hydraulic cylinder through the first electromagnetic switch valve, and the second oil port of the hydraulic pump motor is connected to the rodless cavity of the hydraulic cylinder through the second electromagnetic switch valve, characterized in that It includes a speed sensor and a speed control device, the speed sensor is used to feed back the displacement speed of the hydraulic cylinder, the speed control device is electrically connected to the speed sensor and the motor controller respectively, and the speed control device is used to execute the method according to any one of claims 1 to 7.

9. The speed optimization system of the electrostatic-hydraulic drive operating system according to claim 8, characterized in that: The invention also includes a first pressure sensor and a second pressure sensor; the first pressure sensor is used to feedback the pressure value of the rod cavity, and the second pressure sensor is used to feedback the pressure value of the rodless cavity; The speed control device includes a full bucket rate calculation unit, a speed trajectory planning unit and a speed control unit; The full bucket rate calculation unit is electrically connected to the first pressure sensor and the second pressure sensor, and is used to calculate the full bucket rate at the initial moment of system operation based on the rod chamber pressure value of the hydraulic cylinder in the initial state fed back by the first pressure sensor and the rodless chamber pressure value of the hydraulic cylinder in the initial state fed back by the second pressure sensor; The speed trajectory planning unit is electrically connected to the full bucket rate calculation unit, and is used to calculate an optimal control input curve that minimizes the Hamiltonian function of the electrostatic hydraulic drive system, and calculate an optimal speed trajectory curve for the hydraulic cylinder in the system based on the optimal control input curve; The speed control unit is electrically connected to the speed trajectory planning unit, and is used to use the optimal control input curve as a feedforward input, combined with the feedback closed-loop control of the current moving speed of the hydraulic cylinder, to output a control signal to the motor controller so that the hydraulic cylinder operates according to the optimal speed trajectory curve.

10. The speed optimization system of the electrostatic hydraulic drive operating system according to claim 8, characterized in that: The electrostatic hydraulic drive operating system further includes a first safety valve, a second safety valve, a low-pressure accumulator, a first hydraulically controlled one-way valve, a second hydraulically controlled one-way valve, a third safety valve, and a fourth safety valve; The inlet of the first hydraulically controlled one-way valve is connected to the port of the first solenoid switch valve connected to the rod chamber, the outlet of the first hydraulically controlled one-way valve is connected to the outlet of the second hydraulically controlled one-way valve, the inlet of the second hydraulically controlled one-way valve is connected to the port of the second solenoid switch valve connected to the rodless chamber, the low-pressure accumulator is connected between the first hydraulically controlled one-way valve and the second hydraulically controlled one-way valve, and the low-pressure accumulator replenishes hydraulic oil to the first oil port through the first hydraulically controlled one-way valve; The first safety valve is used to limit the maximum pressure between the first oil port and the first electromagnetic switch valve, and the second safety valve is used to limit the maximum pressure between the second oil port and the second electromagnetic switch valve; the third safety valve is used to limit the maximum pressure between the first electromagnetic switch valve and the rod chamber, and the fourth safety valve is used to limit the maximum pressure between the second electromagnetic switch valve and the rodless chamber.

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