Hydraulic cylinder displacement control system and method based on independent control of valve ports

Abstract

The present application belongs to the technical field of hydraulic control, and particularly relates to a hydraulic cylinder displacement control system and method based on independent control of valve ports, which comprises a hydraulic power source, a safety valve, an import and export independent control valve group, a hydraulic cylinder, an operating handle, a multifunctional controller, a cloud storage, a pressure sensor I, a pressure sensor II, a pressure sensor III, a rotating speed sensor and a temperature sensor. The present application can detect and control system flow, realize accurate control of the position of the hydraulic cylinder, and monitor system power, energy consumption and efficiency in real time, and is used for predictive maintenance and fault diagnosis.

Description

Technical Field

[0001] This invention belongs to the field of hydraulic control technology, and specifically relates to a hydraulic cylinder displacement control system and method based on independent valve port control. Background Technology

[0002] In the field of construction machinery, centralized hydraulic power sources are widely used for power supply, with multiple actuators operating by distributing power through hydraulic valves. The speed of the actuators is entirely controlled by the flow rate of the control valve system, and the operator controls the position of the actuators by controlling their speed. However, due to the complex operating environment of the actuators and the wide range of load force variations, the speed fluctuates greatly. Differential pressure compensators are often used to control the flow rate at the valve orifice. Although this method can reduce the impact of load pressure changes on the output flow rate of the control valve, the control accuracy is relatively low due to the influence of hydraulic force. The added compensator also increases the throttling loss of the valve, increasing the heat generation and power loss of the system.

[0003] In theory, if a sensor exists that is easy to install and can detect flow rate with high precision and dynamics without throttling, the actuator speed can be precisely controlled through closed-loop flow control, unaffected by load changes; or the actuator's speed and displacement can be accurately controlled by directly detecting its position and speed. However, existing flow sensors must be installed in series in the hydraulic pipeline, which is inconvenient. They also suffer from high pressure loss and cost, and their dynamic response is slow due to limitations in their operating principle, making it impossible to accurately detect flow rate for closed-loop actuator speed control. While displacement sensors can accurately control the speed and displacement of hydraulic actuators and detect their operating status in real time, the maintenance and upkeep of displacement sensors installed externally to the hydraulic actuator are very troublesome. In harsh and complex operating environments, the sensors are susceptible to contamination from oil stains, solutions, and dust, resulting in poor reliability and reduced lifespan. If a displacement sensor is built into the actuator, although its lifespan is improved, the manufacturing cost of the hydraulic actuator is undoubtedly increased.

[0004] Moreover, the existing hydraulic systems of construction machinery have a low level of intelligence, lack the ability to learn and adapt to changes in load, environment, and themselves, and cannot perform fault diagnosis and life prediction. They are all repaired after accidents, leading to safety accidents and economic losses. They cannot use historical data for analysis, calculation, comparison, and decision-making, resulting in serious energy waste.

[0005] Based on the above problems, a new valve-controlled hydraulic cylinder flow detection and speed / position control system is needed to ensure that the actuator operates stably regardless of load changes and to guarantee the safety and reliability of the equipment. Summary of the Invention

[0006] To address the above problems, this invention aims to provide a hydraulic cylinder displacement control system and method based on independent valve port control, which can control flow rate, detect and measure flow rate, as well as power, energy and efficiency, and can also be used for predictive maintenance and fault diagnosis.

[0007] To achieve the above objectives, the present invention adopts the following technical solution:

[0008] A hydraulic cylinder displacement control system based on independent valve port control includes a hydraulic power source 1, a safety valve 2, an inlet and outlet independent control valve group 3, and a hydraulic cylinder 4. It is further equipped with a pressure sensor I, a pressure sensor II, a pressure sensor III, a speed sensor 12, a temperature sensor 13, an operating handle 23, a multi-function controller 24, and a cloud storage 21.

[0009] The hydraulic power source includes: an electric motor 9, a hydraulic pump 10, and an oil tank 11. The hydraulic pump is driven by the electric motor. The oil inlet of the hydraulic pump is connected to the oil tank. The oil outlet of the hydraulic pump is connected to the inlet and outlet independent valve group. The oil inlet of the safety valve is connected to the oil outlet of the hydraulic pump. The oil outlet of the safety valve is connected to the oil tank.

[0010] The aforementioned independent inlet and outlet control valve group consists of a first-position two-way proportional valve 5, a second-position two-way proportional valve 6, a third-position two-way proportional valve 7, and a fourth-position two-way proportional valve 8; the oil port C of the second-position two-way proportional valve... Ⅱ And the oil port C of the second position two-way proportional valve III Ⅲ Connect the oil port C of the second position 2-way proportional valve. Ⅰ And the oil port C of the second position two-way proportional valve of the fourth position Ⅳ Connected to the oil tank respectively, the oil port D of the second position two-way proportional valve. Ⅰ Port D of the second-position two-way proportional valve Ⅱ The oil port D of the second-position two-way proportional valve is connected to chamber A of the hydraulic cylinder. Ⅲ Port D of the second-position two-way proportional valve (N4) Ⅳ It is connected to chamber B of the hydraulic cylinder;

[0011] Pressure sensor I is connected to the outlet of the hydraulic pump, pressure sensor II is connected to chamber A of the hydraulic cylinder, and pressure sensor III is connected to chamber B of the hydraulic cylinder.

[0012] The hydraulic power source is equipped with a speed sensor and a temperature sensor connected to the hydraulic pump outlet.

[0013] The multi-functional controller includes: signal processing module 22, control and calculation module 14, integration module 15, displacement correction module 16, data storage module 17, communication module 18, display module 19, and fault diagnosis module 20.

[0014] The signal processing module receives the oil supply pressure. pS Hydraulic cylinder A chamber pressure p A Hydraulic cylinder B chamber pressure p B Control valve displacement setting signal x s Speed ​​signal n Hydraulic pump displacement signal V p The temperature signal T is output and connected to the input of the control and calculation module and the input of the storage module.

[0015] The input terminal of the control and calculation module is connected to the operating handle and the output terminal of the calibration module. The control valve displacement setting signal and the hydraulic pump displacement setting signal are respectively connected to the input terminals of the control valve displacement and the hydraulic pump displacement. The output terminal of the control and calculation module is connected to the input terminal of the integration module and the input terminal of the storage module.

[0016] The output of the integration module is connected to the input of the correction module and the input of the storage module.

[0017] The displacement correction module receives signals from the position transmitting device. The input terminal of the displacement correction module is connected to the output terminal of the integration module, and the output terminal of the displacement correction module is connected to the input terminal of the control and calculation module.

[0018] The input terminal of the storage module is connected to the output terminal of the signal processing module, the output terminal of the control and calculation module, and the output terminal of the integration module; the output terminal of the storage module is connected to the fault diagnosis module, the display module, and the communication module, and the communication module is connected to the cloud storage.

[0019] Furthermore, the independent inlet and outlet control valve group includes four two-position two-way proportional valves or two three-position four-way proportional valves.

[0020] Furthermore, magnetic induction marks distributed along the piston rod axis are machined on the hydraulic cylinder piston rod as position monitoring points 4-1, and the induction signal is input to the displacement correction module through the sensing of the position signaling device 4-2.

[0021] Furthermore, the signal processing module includes a digital filter and a normalization processing algorithm. The input signal is connected to the digital filter, and the output signal of the digital filter is output to the input terminal of the normalization processing algorithm.

[0022] Furthermore, the control and calculation module uses the output parameters from the signal processing module to calculate the following parameters according to the following formula:

[0023] Single-rod hydraulic cylinder flow rate:

[0024] (1)

[0025] Hydraulic cylinder speed:

[0026]

[0027] Total system power:

[0028] (3)

[0029] System useful power:

[0030] (4);

[0031] In the formula, , C d - Valve orifice flow coefficient, A(x) - Valve orifice area, ρ - Oil density A A -Area of ​​chamber A of the hydraulic cylinder.

[0032] Furthermore, the integration module receives the output parameters from the control and calculation module and calculates the following parameters according to the following formula:

[0033] Theoretical displacement of hydraulic cylinder:

[0034] (2)

[0035] Total system power:

[0036] (6)

[0037] Useful work of the system:

[0038] (7)

[0039] System efficiency:

[0040] (8).

[0041] Furthermore, the display module displays dynamic curves of the parameters stored in the storage module;

[0042] The communication module is Ethernet, Industrial Internet or Bluetooth, which transmits data from the data storage module to the cloud storage and receives data information stored in the cloud storage.

[0043] The fault diagnosis module performs fault analysis and proactive maintenance on the hydraulic system based on the system parameters stored in the module.

[0044] A method for flow detection and position control of a hydraulic cylinder with independent valve port control includes the following steps:

[0045] Step 1: Collect the pressure signal from the pressure sensor ps , p A , p B Control valve displacement setting signal x s Hydraulic system temperature T The data is input into the control and calculation module, and then processed according to the flow calculation formula. The flow rate through control valves A and B is calculated in real time. Q Divide by the area of ​​the corresponding hydraulic cylinder cavity to obtain the hydraulic cylinder piston rod speed. v ;

[0046] Step 2: The hydraulic cylinder piston rod speed calculated from Step 1 v The input is fed into the integration module, which integrates the hydraulic cylinder velocity over a certain period of time to obtain the theoretical displacement of the hydraulic cylinder. s , with the initial system memory location x Summing 0 yields the theoretical position of the hydraulic cylinder. x t ;

[0047] Step 3: Perform hydraulic cylinder position calibration, and adjust the theoretical position of the hydraulic cylinder obtained in Step 2. x t The actual location transmitted by the location transmitting device x a Compare, if x t > x a This will correspondingly increase the speed correction factor. k Similarly, if x t < x a Therefore, the speed correction factor should be reduced accordingly. k ;

[0048] Step 4: Apply the speed correction coefficient obtained in Step 3. k The input is fed into the control and calculation module to calculate the control valve opening, which is then converted into a control signal to correct the control valve flow and thus adjust the hydraulic cylinder speed. Finally, after multiple iterations and corrections, the theoretical position after flow integration is determined. x t Compared with the actual location of the monitoring point x a near.

[0049] Compared with the prior art, the present invention has the following beneficial effects:

[0050] 1. This invention patent can detect and control flow with high precision without the need for a flow sensor, solving the problems of existing flow sensors being unable to control flow in a closed loop, having high cost, complex installation, and large pressure loss. The control valve itself can also perform the function of a flow sensor, realizing the integration of flow detection and control.

[0051] 2. The control and calculation module of this invention calculates the system flow rate through the flow rate formula. After parameter integration and correction, it can control the speed and position of the hydraulic cylinder at low cost and with high reliability without the need for expensive high-precision displacement sensors.

[0052] 3. This invention patent innovatively proposes a novel flow control method that eliminates the need for a pressure compensator in the hydraulic system. By using the valve orifice flow calculation formula, the valve flow information can be obtained, and the displacement of the hydraulic valve core can be controlled to reduce the impact of load pressure changes on the output flow of the control valve.

[0053] 4. This invention calculates the basic parameters of the hydraulic system to obtain the power, energy, and efficiency of the hydraulic pump, control valve, hydraulic cylinder, and the entire hydraulic system; based on real-time monitoring of energy loss and energy efficiency, the system parameters can be controlled to improve overall energy efficiency.

[0054] 5. This invention can dynamically sense and record information such as valve opening, pressure, speed, displacement, power and energy in real time. Through intelligent algorithms, it can analyze the operating status and health status of key components in the system, estimate the remaining life of key components, and perform fault prediction. It can manage the data of each component and its entire life cycle, making the entire hydraulic system intelligent. This is a function that traditional hydraulic systems do not have. Attached Figure Description

[0055] Figure 1 This is a system schematic diagram of Embodiment 1 of the present invention;

[0056] Figure 2 This is a system schematic diagram of Embodiment 2 of the present invention;

[0057] Figure 3 This is a structural diagram of the hydraulic cylinder of the present invention;

[0058] Figure 4 This is a flowchart of the control method of the present invention.

[0059] In the diagram, 1-hydraulic power source, 2-safety valve, 3-inlet / outlet independent control valve group, 4-hydraulic cylinder, 5-first position two-way proportional valve (I), 6-second position two-way proportional valve (II), 7-third position two-way proportional valve (III), 8-fourth position two-way proportional valve (IV), 9-electric motor, 10-hydraulic pump, 11-oil tank, 101-pressure sensor I, 102-pressure sensor II, 103-pressure sensor III, 12-speed sensor, 13-temperature sensor, 14-control and calculation... Calculation module, 15-Integration module, 16-Displacement correction module, 17-Data storage module, 18-Communication module, 19-Display module, 20-Fault diagnosis module, 21-Cloud storage, 22-Signal processing module, 23-Operating handle, 24-Multi-function controller; 31-First three-position four-way proportional valve, 32-Second three-position four-way proportional valve, 4-1-Position monitoring point, 4-2-Position signaling device, 4-3-Zero position reference point, 4-4-Piston rod. Detailed Implementation

[0060] The principles and structure of the invention will be further described in detail below with reference to the accompanying drawings and embodiments. Those skilled in the art will be able to understand and implement the invention after reading the specific embodiments. These embodiments are a detailed description of the invention and do not impose any limitations on the invention.

[0061] The meanings of the parameters in the formulas in this article are as follows: A A -Area of ​​hydraulic cylinder A chamber A B - Area of ​​chamber B of the hydraulic cylinder Q A -Flow rate in hydraulic cylinder A chamber Q B -Flow rate in chamber B of the hydraulic cylinder v -Hydraulic cylinder speed, p S - Oil supply pressure, p A - Pressure in chamber A of the hydraulic cylinder p B -Pressure in chamber B of the hydraulic cylinder P 1- Total system power, P 2-System useful power, P 3- Control valve throttling loss power, s - Theoretical displacement of the hydraulic cylinder x t - Theoretical position of the hydraulic cylinder x 0 - Initial position of the hydraulic cylinder x -Distance between two adjacent magnetic induction markers E 1-Total system power, E 2-System useful work, E 3-Valve port energy loss, η -System efficiency, k - Correction factor, n -Hydraulic pump speed, V p - Hydraulic pump displacement T - Oil temperature c - Control valve orifice flow coefficient w -Control valve area gradient, x s - Control valve displacement setting signal u sp -Hydraulic pump displacement setting signal, C d -Valve orifice flow coefficient, A(x) -Valve orifice area, ρ -Oil density, t -Time.

[0062] Example 1

[0063] like Figure 1 As shown, a hydraulic cylinder displacement control system and method based on independent valve port control includes: a hydraulic power source 1, a safety valve 2, an inlet and outlet independent control valve group 3, a hydraulic cylinder 4, a pressure sensor I 101, a pressure sensor II 102, a pressure sensor III 103, a speed sensor 12, a temperature sensor 13, an operating handle 23, a multi-functional controller 24, and a cloud storage 21.

[0064] The hydraulic power source 1 includes: an electric motor 9, a hydraulic pump 10, and an oil tank 11. The hydraulic pump 10 is driven by the electric motor 9. The oil inlet of the hydraulic pump is connected to the oil tank 11, and the oil outlet is connected to the inlet and outlet independent control valve group 3. The oil inlet of the safety valve 2 is connected to the oil outlet of the hydraulic pump 10, and the oil outlet of the safety valve 2 is connected to the oil tank 11.

[0065] The independent inlet and outlet control valve group 3 includes a first-position two-way proportional valve 5, a second-position two-way proportional valve 6, a third-position two-way proportional valve 7, and a fourth-position two-way proportional valve 8; the oil port C of the second-position two-way proportional valve... Ⅱ And the oil port C of the second position two-way proportional valve III Ⅲ The oil port C of the second position two-way proportional valve is connected to the outlet of hydraulic pump 10 respectively. Ⅰ And the oil port C of the second position two-way proportional valve of the fourth position Ⅳ The oil ports D of the first and second position two-way proportional valves are respectively connected to the oil tank. Ⅰ D Ⅱ The oil port D of the rodless chamber of the hydraulic cylinder is connected to the second-position two-way proportional valve III and the second-position two-way proportional valve IV. Ⅲ D Ⅳ It is connected to the rod-side cavity of the hydraulic cylinder.

[0066] Pressure sensor I is connected to the outlet of hydraulic pump 10, pressure sensor II is connected to chamber A of hydraulic cylinder 4, and pressure sensor III is connected to chamber B of hydraulic cylinder.

[0067] The hydraulic power source 1 is equipped with a speed sensor 12 and a temperature sensor 13 connected to the outlet of the hydraulic pump 10.

[0068] The multi-functional controller includes: signal processing module 22, control and calculation module 14, integration module 15, displacement correction module 16, data storage module 17, communication module 18, display module 19, and fault diagnosis module 20.

[0069] When the actuator is a hydraulic cylinder, a position monitoring point 4-1 and a position signaling device 4-2 are installed on the piston rod of the hydraulic cylinder. For example... Figure 3 As shown, the piston rod 4-4 is pre-treated by grooving on a lathe before assembly. Specifically, an annular groove is machined every 50 mm, and the machined annular grooves are filled with magnetic material to form position monitoring points 4-1 with sensing function. The zero position reference point 4-3 is the piston rod when it is fully retracted. Each time the position monitoring point 4-1 passes the position signaling device 4-2, the position signaling device 4-2 will send a signal to the displacement correction module 16. If the hydraulic cylinder piston rod 4-4 extends, the actual position of the piston rod is... x a Add 50 mm to the initial position. If the hydraulic cylinder piston rod 4-4 retracts, the actual position of the piston rod will be... x a The position will be reduced by 50 mm from the initial position. After each run, the storage and display unit will save the end position of the hydraulic cylinder piston rod, which will be used as the initial position data for the next run.

[0070] The signal processing module will process the oil supply pressure collected by the sensor. p S Hydraulic cylinder A chamber pressure p A Hydraulic cylinder B chamber pressure p B , control valve orifice opening x s Hydraulic power source speed n Hydraulic pump displacement V p The signal is filtered and normalized to prepare for further data calculation and analysis.

[0071] The flow control method for combined speed and position control of valve-controlled hydraulic cylinders includes the following specific steps:

[0072] Step 1: The control and calculation module receives the system parameters output by the signal processing module and calculates the flow rate into the single-rod hydraulic cylinder 10 using formula (1):

[0073] (1)

[0074] The speed of the hydraulic cylinder is ,in A A The area of ​​chamber A of the hydraulic cylinder;

[0075] Step 2: The integration module 12 receives the parameters from the control and calculation module 11 and uses formula (2) to calculate the theoretical displacement of the single-rod hydraulic cylinder 10. s :

[0076] (2)

[0077] Theoretical displacement s relative to the initial position of the hydraulic cylinder x By summing the values ​​of 0 and 1, the theoretical position of hydraulic cylinder 10 can be obtained. x t : x t = x 0+ s If hydraulic cylinder 10 extends, the theoretical displacement is... s >0; If hydraulic cylinder 10 performs a retracting motion, the theoretical displacement s <0.

[0078] Step 3: Each time the calibration module receives a signal transmitted from the position transmitter 4-2, it will adjust the actual position... x a The theoretical position of the hydraulic cylinder calculated by the integrator module x t Perform corrections and calculate the position difference: ∆x = x t — x a The speed correction factor is... , x The distance between two adjacent magnetic induction markers is 50 mm;

[0079] The correction module will adjust the speed correction factor. k The corrected theoretical speed of the hydraulic cylinder is transmitted to the control and calculation module 11. v’ = k • v The theoretical flow rate output by the control valve is... Q A = A A • v’The control valve displacement setting is obtained by applying the flow calculation formula. x s This is then converted into a control valve signal to control the valve opening.

[0080] After multiple iterations and corrections, the theoretical position of the flow integral was finally determined. x t Compared with the actual location of the monitoring point x a near.

[0081] The control and calculation module can calculate the total power of the system using formulas (3), (4), and (5). P 1. System useful power P 2. Control valve throttling loss power P 3:

[0082] (3)

[0083] (4)

[0084] (5)

[0085] In the formula, , .

[0086] The integral module uses formulas (6), (7), and (8) to calculate the total power of the system. E 1. System useful work E 2. Energy loss at the control valve orifice E 3:

[0087] (6)

[0088] (7)

[0089] (8)

[0090] System efficiency is .

[0091] The storage module stores the hydraulic pump speed. n Hydraulic pump displacement V p , control valve opening x s Oil temperature T Oil supply pressure p S Hydraulic cylinder A chamber pressure p A Hydraulic cylinder B chamber pressure pB Flow rate into hydraulic cylinder A chamber Q A Flow rate out of hydraulic cylinder B chamber Q B Total system power P 1. System useful power P 2. Hydraulic cylinder speed v Hydraulic cylinder initial position x 0. Total System Power E 1. System useful work E 2. System efficiency η Store it.

[0092] The fault diagnosis module can utilize information such as system pressure, flow rate, power, and energy efficiency recorded by the storage module to detect and preprocess fault signals in the hydraulic system. Assuming a system efficiency threshold... λ η Energy threshold λ E If system efficiency η < λ η The hydraulic system will shut down. Pressure, flow, and power information will be compared with curves from a healthy state to identify fault characteristics. Using an expert database, the process of identifying fault characteristics and their causes can be completed to accurately locate the fault. If the useful work accumulated by the hydraulic cylinder during operation... E 2> λ E Theoretically, the hydraulic system can be considered to have reached a state of fatigue, and the system will perform proactive shutdown maintenance.

[0093] The display module can display data curves of pressure, flow rate, hydraulic cylinder position, system power and system energy consumption in the storage module in real time, realizing the visualization of hydraulic system parameters.

[0094] The communication module can upload data from the storage module to the cloud storage, which has a complete automatic data backup mechanism and can store data throughout the entire system lifecycle, laying the foundation for further optimization of system energy efficiency.

[0095] Example 2

[0096] like Figure 2 As shown, a hydraulic cylinder displacement control system and method based on independent valve port control is disclosed. The system configuration of this embodiment differs from that of Embodiment 1 in that the inlet and outlet independent control valve group 3 includes a first three-position four-way proportional valve 31 and a second three-position four-way proportional valve 32. In this embodiment, only the opening of the three-position four-way proportional valve needs to be controlled to control the speed and displacement of the hydraulic cylinder. The oil port F of the first three-position four-way proportional valve 31... Ⅱ and three-position four-way proportional valve 6-port G ⅠConnected to the hydraulic pump outlet, the first three-position four-way proportional valve 31's port F Ⅰ Second and third position four-way proportional valve 32 port G Ⅱ The oil port F of the first three-position four-way proportional valve 31 is connected to the oil tank respectively. Ⅳ The oil port G of the second-third position four-way proportional valve 32 is connected to the hydraulic cylinder A chamber via an oil circuit. Ⅲ It is connected to chamber B of the hydraulic cylinder via an oil circuit. Figure 2 It can be seen that the first three-position four-way proportional valve 31 and the second three-position four-way proportional valve 32 can achieve the following: Figure 1 The functions of the two-way proportional valve 5 (position I), the two-way proportional valve 6 (position II), the two-way proportional valve 7 (position III), and the two-way proportional valve 8 (position IV).

Claims

1. A hydraulic cylinder displacement control system based on independent valve port control, characterized in that, It includes a hydraulic power source (1), a safety valve (2), an inlet and outlet independent control valve group (3), a hydraulic cylinder (4), and further includes a pressure sensor I, a pressure sensor II, a pressure sensor III, a speed sensor (12), a temperature sensor (13), an operating handle (23), a multi-function controller (24), and a cloud storage (21). The hydraulic power source includes: an electric motor (9), a hydraulic pump (10), and an oil tank (11). The hydraulic pump is driven by the electric motor. The oil inlet of the hydraulic pump is connected to the oil tank. The oil outlet of the hydraulic pump is connected to the inlet and outlet independent valve group. The oil inlet of the safety valve is connected to the oil outlet of the hydraulic pump. The oil outlet of the safety valve is connected to the oil tank. The aforementioned independent inlet and outlet control valve group consists of a first two-position two-way proportional valve (5), a second two-position two-way proportional valve (6), a third two-position two-way proportional valve (7), and a fourth two-position two-way proportional valve (8); the oil port C of the second two-position two-way proportional valve... Ⅱ And the oil port C of the second position two-way proportional valve III Ⅲ Connect the oil port C of the second position 2-way proportional valve. Ⅰ And the oil port C of the second position two-way proportional valve of the fourth position Ⅳ Connected to the oil tank respectively, the oil port D of the second position two-way proportional valve. Ⅰ Port D of the second-position two-way proportional valve Ⅱ The oil port D of the second-position two-way proportional valve is connected to chamber A of the hydraulic cylinder. Ⅲ Port D of the second-position two-way proportional valve (N4) Ⅳ It is connected to chamber B of the hydraulic cylinder; Pressure sensor I is connected to the outlet of the hydraulic pump, pressure sensor II is connected to chamber A of the hydraulic cylinder, and pressure sensor III is connected to chamber B of the hydraulic cylinder. The hydraulic power source is equipped with a speed sensor and a temperature sensor connected to the hydraulic pump outlet. The multi-functional controller includes: a signal processing module (22), a control and calculation module (14), an integration module (15), a displacement correction module (16), a data storage module (17), a communication module (18), a display module (19), and a fault diagnosis module (20). The signal processing module receives the oil supply pressure. p S Hydraulic cylinder A chamber pressure p A Hydraulic cylinder B chamber pressure p B Control valve displacement setting signal x s Speed ​​signal n Hydraulic pump displacement signal V p The temperature signal T is output and connected to the input of the control and calculation module and the input of the storage module. The input terminal of the control and calculation module is connected to the operating handle and the output terminal of the calibration module. The control valve displacement setting signal and the hydraulic pump displacement setting signal are respectively connected to the input terminals of the control valve displacement and the hydraulic pump displacement. The output terminal of the control and calculation module is connected to the input terminal of the integration module and the input terminal of the storage module. The output of the integration module is connected to the input of the correction module and the input of the storage module. The displacement correction module receives signals from the position transmitting device. The input terminal of the displacement correction module is connected to the output terminal of the integration module, and the output terminal of the displacement correction module is connected to the input terminal of the control and calculation module. The input terminal of the storage module is connected to the output terminal of the signal processing module, the output terminal of the control and calculation module, and the output terminal of the integration module; the output terminal of the storage module is connected to the fault diagnosis module, the display module, and the communication module, and the communication module is connected to the cloud storage. The control and calculation module uses the output parameters from the signal processing module to calculate the following parameters according to the following formula: Single-rod hydraulic cylinder flow rate: （1） Hydraulic cylinder speed: Total system power: （3） System useful power: （4）； In the formula, , C d - Valve orifice flow coefficient, A(x) - Valve orifice area, ρ - Oil density A A -Area of ​​chamber A in the hydraulic cylinder; The integration module receives the output parameters from the control and calculation module and calculates the following parameters according to the following formula: Theoretical displacement of hydraulic cylinder: （2） Total system power: （6） Useful work of the system: （7） System efficiency: （8）； Calculated hydraulic cylinder piston rod speed v The input is fed into the integration module, which integrates the hydraulic cylinder velocity over a certain period of time to obtain the theoretical displacement of the hydraulic cylinder. s , with the initial system memory location x Summing 0 yields the theoretical position of the hydraulic cylinder. x t ; The theoretical position of the hydraulic cylinder obtained x t The actual location transmitted by the location transmitting device x a Compare, if x t > x a This will correspondingly increase the speed correction factor. k Similarly, if x t < x a Therefore, the speed correction factor should be reduced accordingly. k ; The obtained speed correction coefficient k The input is fed into the control and calculation module to calculate the control valve opening, which is then converted into a control signal to correct the control valve flow and thus adjust the hydraulic cylinder speed. Finally, after multiple iterations and corrections, the theoretical position after flow integration is determined. x t Compared with the actual location of the monitoring point x a near.

2. The hydraulic cylinder displacement control system based on independent valve port control according to claim 1, characterized in that, The piston rod of the hydraulic cylinder is machined with magnetic induction marks distributed along the piston rod axis as position monitoring points (4-1), and the induction signal is input to the displacement correction module through the sensing of the position signaling device (4-2).

3. The hydraulic cylinder displacement control system based on independent valve port control according to claim 1, characterized in that, The signal processing module includes a digital filter and a normalization algorithm. The input signal is connected to the digital filter, and the output signal of the digital filter is output to the input of the normalization algorithm.

4. A hydraulic cylinder displacement control system based on independent valve port control according to claim 1, characterized in that: The display module displays dynamic curves of the parameters stored in the storage module; The communication module is Ethernet, Industrial Internet or Bluetooth, which transmits data from the data storage module to the cloud storage and receives data information stored in the cloud storage. The fault diagnosis module performs fault analysis and proactive maintenance on the hydraulic system based on the system parameters stored in the module.

5. A control method for a hydraulic cylinder displacement control system based on independent valve port control as described in claim 1, characterized in that, The system's operation process includes the following steps: Step 1: Collect the pressure signal from the pressure sensor p s , p A , p B Control valve displacement setting signal x s Hydraulic system temperature T The data is input into the control and calculation module, and then processed according to the flow calculation formula. The flow rate through control valves A and B is calculated in real time. Q Divide by the area of ​​the corresponding hydraulic cylinder cavity to obtain the hydraulic cylinder piston rod speed. v ; Step 2: The hydraulic cylinder piston rod speed calculated from Step 1 v The input is fed into the integration module, which integrates the hydraulic cylinder velocity over a certain period of time to obtain the theoretical displacement of the hydraulic cylinder. s , with the initial system memory location x Summing 0 yields the theoretical position of the hydraulic cylinder. x t ; Step 3: Perform hydraulic cylinder position calibration, and adjust the theoretical position of the hydraulic cylinder obtained in Step 2. x t The actual location transmitted by the location transmitting device x a Compare, if x t > x a This will correspondingly increase the speed correction factor. k Similarly, if x t < x a Therefore, the speed correction factor should be reduced accordingly. k ; Step 4: Apply the speed correction coefficient obtained in Step 3. k The input is fed into the control and calculation module to calculate the control valve opening, which is then converted into a control signal to correct the control valve flow and thus adjust the hydraulic cylinder speed. Finally, after multiple iterations and corrections, the theoretical position after flow integration is determined. x t Compared with the actual location of the monitoring point x a near.

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