Hardware-in-the-loop simulation method for electro-hydraulic drive control system of engineering robot arm

Abstract

This invention discloses a hardware-in-the-loop (HIL) simulation method for an electro-hydraulic drive control system of an engineering robot boom, comprising the following steps: establishing a mathematical model of the valve-controlled hydraulic cylinder and a position tracking control algorithm model for the boom's electro-hydraulic drive system; establishing a hardware-in-the-loop simulation platform, including a host computer, a target controller, sensors, and an actual valve-controlled hydraulic cylinder test bench; acquiring sensor data from the test bench via a data acquisition card and sending it to the host computer for processing through an open-loop identification experiment; obtaining the actual parameters of the valve-controlled asymmetric cylinder mathematical model using a parameter identification method; designing a position tracking controller and generating controller code based on this; downloading the controller code to the target controller for HIL simulation experiments and analyzing the actual control effect. This invention enables rapid verification of the control algorithm for the electro-hydraulic drive system of an engineering robot boom, shortens the controller development cycle, and reduces development costs.

Description

Technical Field

[0001] This invention relates to the field of boom control for engineering robots, and specifically to a hardware-in-the-loop simulation method for an electro-hydraulic drive control system for an engineering robot boom. Background Technology

[0002] With the development of automation and intelligence in construction machinery and equipment, the deep integration of robot technology with the construction machinery field has enabled the robotization of construction operation equipment, which can effectively improve the efficiency, accuracy and safety of construction operations. It is now widely used in mining, aerospace, military, infrastructure and other fields.

[0003] Hydraulic-driven robotic arms are the main working devices of engineering robots, and their electro-hydraulic drive control system is crucial for achieving high-precision control of the arm. However, due to the strong nonlinearity, strong external load interference, and uncertainties in system parameters during operation, traditional PID control methods are insufficient to meet the motion control requirements of hydraulic-driven robotic arms. Therefore, researching high-precision motion control algorithms for the arms of engineering robots has become an urgent problem to be solved in the field of engineering machinery equipment.

[0004] However, the development and deployment of motion control algorithms for booms in engineering equipment currently face two main challenges: First, engineering robot booms are typical mechatronic systems, typically operating in dynamic, unstructured, and unknown environments. Therefore, establishing complete and accurate pure simulation models is difficult, reducing the reliability of simulation results. Second, ensuring construction progress and safety makes on-site testing of control algorithms costly, time-consuming, and prone to safety accidents, significantly hindering their development and deployment. Therefore, researching rapid development and verification technologies for control algorithms is crucial for the development of the engineering machinery equipment field. Summary of the Invention

[0005] The purpose of this invention is to provide a hardware-in-the-loop simulation method for the electro-hydraulic drive control system of an engineering robot boom, so as to achieve rapid development and verification of the control algorithm.

[0006] To achieve the above objectives, the specific technical solution adopted by the present invention is as follows:

[0007] A hardware-in-the-loop simulation method for an electro-hydraulic drive control system of an engineering robot boom, characterized by comprising the following steps:

[0008] 1) Establish a mathematical model of the valve-controlled hydraulic cylinder of the boom electro-hydraulic drive system and design a position tracking control algorithm model;

[0009] 2) Establish a hardware platform for semi-physical simulation, which includes a host computer, a target controller, sensors, and a valve-controlled hydraulic cylinder test bench. The host computer is used for designing, compiling, and downloading Simulink simulation models, as well as displaying and saving experimental data. The target controller runs a real-time operating system for acquiring, calculating, sending, and uploading experimental data. The sensors record the actual operating data of the valve-controlled hydraulic cylinder test bench. The valve-controlled hydraulic cylinder test bench simulates the actual working state of the boom electro-hydraulic drive system under engineering operation conditions.

[0010] 3) Run a hardware-in-the-loop simulation platform to conduct open-loop parameter identification experiments for valve-controlled hydraulic cylinder systems. Obtain data from the valve-controlled hydraulic cylinder test bench during operation through a host computer. After preprocessing the data, use parameter identification methods to obtain the identified system parameters and verify the accuracy of parameter identification through a simulation model.

[0011] 4) Conduct a hardware-in-the-loop simulation experiment for position tracking control. Obtain the position tracking controller through the mathematical model of the valve-controlled hydraulic cylinder system after parameter identification, compile and generate controller code, download it from the host computer to the target machine controller, record the operating data of the valve-controlled hydraulic cylinder test bench, and analyze and verify the position tracking control effect.

[0012] In step 1 above, the mathematical model of the valve-controlled hydraulic cylinder and the position tracking control algorithm model of the boom electro-hydraulic drive system include the flow continuity equation of the valve-controlled hydraulic cylinder without considering the influence of internal and external leakage of the hydraulic cylinder:

[0013]

[0014] Where, V1 = V 10 +A1x and V2 = V 20 -A2x represent the effective volumes of the rodless chamber and the rod chamber of the hydraulic cylinder, respectively. V 10 and V 20 Let β be the initial volume of the rodless cavity, the rod cavity, and the connected pipe, respectively. e The effective bulk modulus, P1 and P2 are the pressures of the rodless and rod chambers of the hydraulic cylinder, respectively, A1 and A2 are the effective working areas of the rodless and rod chambers of the hydraulic cylinder, respectively, and Q1 and Q2 are the valve orifice flow rates of the rodless and rod chambers of the hydraulic cylinder.

[0015] According to the valve orifice flow equation, Q1 and Q2 can be expressed as functions of valve core displacement u:

[0016]

[0017] Where c1, c2, c3, and c4 are the gain coefficients of the electro-hydraulic proportional valve, determined by the shape and size of the valve orifice, P S To alleviate oil export pressure, P TThe pressure at the return port;

[0018] According to Newton's second law, the force balance equations for the valve-controlled asymmetric cylinder model can be expressed as:

[0019]

[0020] Where x is the displacement of the valve-controlled hydraulic cylinder, m is the equivalent mass of the piston rod and load, b represents the coefficient of viscous friction, F is the driving force applied by the valve-controlled hydraulic cylinder to the system, and f l The lumped disturbance term in the force balance equation is composed of modeling errors such as parameter uncertainty, time-varying external load disturbance, and nonlinear friction.

[0021] Set the state space variables [x1, x2, x3] T =[x,v,P1A1-P2A2] T Based on the flow continuity equation (1), the valve orifice flow equation (2), and the force balance equation (3), the state-space expression of the valve-controlled hydraulic cylinder can be obtained as follows:

[0022]

[0023] In the formula,

[0024]

[0025] Where x1, x2, and x3 represent the position, velocity, and driving force of the hydraulic cylinder, respectively; m is the equivalent mass of the piston rod and load; b represents the coefficient of viscous friction; and f... l This represents the lumped disturbance term in the force balance equation, composed of modeling errors such as parameter uncertainties, time-varying external load disturbances, and nonlinear frictional forces. β e For the effective bulk modulus, V1 = V 10 +A1x and V2 = V 20 -A2x represent the effective volumes of the rodless chamber and the rod chamber of the hydraulic cylinder, respectively. V 10 and V 20 Let A1 and A2 be the initial volumes of the rodless chamber, rod chamber, and connecting pipe, respectively; let A1 and A2 be the effective working areas of the rodless and rod chambers of the hydraulic cylinder, respectively; let c1, c2, c3, and c4 be the gain coefficients of the electro-hydraulic proportional valve, determined by the shape and size of the valve orifice; and let P1 and P2 be the pressures of the rodless and rod chambers of the hydraulic cylinder, respectively. S To alleviate oil export pressure, P T This refers to the pressure at the return oil port.

[0026] Define the error function:

[0027]

[0028] Where, x1d x1 and x2 represent the desired position and actual position of the hydraulic cylinder, respectively, and F d F and F' represent the input force of the virtual controller and the driving force applied to the system by the valve-controlled hydraulic cylinder, respectively. According to Lyapunov stability theory, the input force F of the virtual controller is obtained. d And the actual valve core input u is:

[0029]

[0030] The parameters are explained by formulas (4), (5), and (6). The feedback gain parameter k is adjusted accordingly. p k v k f This ensures that position tracking meets control performance indicators.

[0031] In step 2 above, the operating data of the hardware-in-the-loop simulation platform includes the position and speed of the hydraulic cylinder piston rod, the pump outlet pressure, the return oil port pressure, the hydraulic cylinder A port pressure, the hydraulic cylinder B port pressure, and the voltage signal input to the valve core.

[0032] In step 3 above, the open-loop parameter identification experiment mainly includes the following steps:

[0033] A. Determine the system identification parameters and design the open-loop identification excitation signal.

[0034] B. Establish an open-loop identification Simulink model for hardware-in-the-loop simulation and obtain the operating data of the hardware-in-the-loop simulation hardware platform.

[0035] C. Zero-phase low-pass filtering is used to preprocess the operating data to obtain hydraulic cylinder piston rod position, speed, pump outlet pressure, return oil port pressure, hydraulic cylinder A port pressure, and hydraulic cylinder B port pressure signals without phase difference.

[0036] D. The parameters of the mathematical model of the valve-controlled hydraulic cylinder are identified using the MATLAB gray box identification function, and the model parameter identification results are obtained.

[0037] E. Using the identified parameters, establish a Simulink simulation model of the valve-controlled hydraulic cylinder. Input the running data from the open-loop parameter identification experiment into the simulation model of the valve-controlled hydraulic cylinder to obtain the simulation model output results, and compare them with the output results of the actual test bench to verify the accuracy of parameter identification.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] This paper presents a hardware-in-the-loop simulation method for the control development of electro-hydraulic drive systems for engineering robots. Using a valve-controlled hydraulic cylinder test bench as the physical foundation, it can simulate the operating state of the electro-hydraulic drive system of the engineering robot boom under different working conditions, solving the problems of long on-site testing cycles, high costs, and significant safety risks of boom motion control algorithms. Using a MATLAB / Simulink real-time simulation model as the software foundation, it enables rapid development, deployment, and verification of control algorithms, improving controller design quality and solving the problems of long controller development cycles and high costs. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of a semi-physical simulation system for a valve-controlled hydraulic cylinder.

[0041] Figure 2 The curve of the excitation signal input;

[0042] Figure 3 To identify the Simulink real-time simulation model diagram for open-loop identification;

[0043] Figure 4 To identify the zero-phase filtered data curve, where (a) is the data before filtering and (b) is the data before filtering;

[0044] Figure 5 Identify the fitted curve for the parameters;

[0045] Figure 6 The Simulink simulation diagrams are used for model verification, where (a) is the Simulink simulation model and (b) is the curve of the model verification result.

[0046] Figure 7 The diagrams show the effect of sinusoidal response position tracking control, where (a) is the effect of PID control and (b) is the effect of the control proposed in this invention. Detailed Implementation

[0047] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. The specific embodiments described herein are merely illustrative and not intended to limit the invention. Furthermore, the technical features involved in the various embodiments of the invention described below can be combined with each other as long as they do not conflict with each other.

[0048] A hardware-in-the-loop simulation method for an electro-hydraulic drive control system of an engineering robot boom includes the following steps:

[0049] 1) Establish a mathematical model of the valve-controlled hydraulic cylinder in the boom electro-hydraulic drive system based on the hydraulic cylinder flow continuity equation, force balance equation, and valve orifice flow equation. On this basis, design a position tracking control algorithm model. Specifically, this includes:

[0050] Ignoring the effects of internal and external leakage in valve-controlled hydraulic cylinders, the flow continuity equation for valve-controlled hydraulic cylinders is as follows:

[0051]

[0052] Where, V1 = V 10 +A1x and V2 = V 20 -A2x represent the effective volumes of the rodless chamber and the rod chamber of the hydraulic cylinder, respectively. V 10 and V 20 These represent the initial volumes of the rodless cavity, the rod cavity, and the connecting pipe, respectively. β e The effective bulk modulus, P1 and P2 are the pressures of the rodless and rod chambers of the hydraulic cylinder, respectively, A1 and A2 are the effective working areas of the rodless and rod chambers of the hydraulic cylinder, respectively, and Q1 and Q2 are the valve orifice flow rates of the rodless and rod chambers of the hydraulic cylinder.

[0053] According to the valve orifice flow equation, Q1 and Q2 can be expressed as functions of valve core displacement u:

[0054]

[0055] Where c1, c2, c3, and c4 are the gain coefficients of the electro-hydraulic proportional valve, determined by the shape and size of the valve orifice, P S To alleviate oil export pressure, P T The pressure at the return port;

[0056] According to Newton's second law, the force balance equations for the valve-controlled asymmetric cylinder model can be expressed as:

[0057]

[0058] Where x is the displacement of the valve-controlled hydraulic cylinder, m is the equivalent mass of the piston rod and load, b represents the coefficient of viscous friction, F is the driving force applied by the valve-controlled hydraulic cylinder to the system, and f l The lumped disturbance term in the force balance equation is composed of modeling errors such as parameter uncertainty, time-varying external load disturbance, and nonlinear friction.

[0059] Set the state space variables [x1, x2, x3] T =[x,v,P1A1-P2A2] T Based on the flow continuity equation (1), the valve orifice flow equation (2), and the force balance equation (3), the state-space expression of the valve-controlled hydraulic cylinder can be obtained as follows:

[0060]

[0061] In the formula,

[0062]

[0063] Where x1, x2, and x3 represent the position, velocity, and driving force of the hydraulic cylinder, respectively; m is the equivalent mass of the piston rod and load; b represents the coefficient of viscous friction; and f... l This represents the lumped disturbance term in the force balance equation, composed of modeling errors such as parameter uncertainties, time-varying external load disturbances, and nonlinear frictional forces. β e For the effective bulk modulus, V1 = V 10 +A1x and V2 = V 20 -A2x represent the effective volumes of the rodless chamber and the rod chamber of the hydraulic cylinder, respectively. V 10 and V 20 Let A1 and A2 be the initial volumes of the rodless chamber, rod chamber, and connecting pipe, respectively; let A1 and A2 be the effective working areas of the rodless and rod chambers of the hydraulic cylinder, respectively; let c1, c2, c3, and c4 be the gain coefficients of the electro-hydraulic proportional valve, determined by the shape and size of the valve orifice; and let P1 and P2 be the pressures of the rodless and rod chambers of the hydraulic cylinder, respectively. S To alleviate oil export pressure, P T The pressure at the return port;

[0064] The controller is designed as a cascaded controller containing an outer loop position controller and an inner loop force controller. Based on the position tracking error, the virtual input signal to the inner loop force controller is obtained from the outer loop position controller, and then the actual valve core input signal is obtained from the inner loop force controller. The error function is defined as follows:

[0065]

[0066] Where, x 1d x1 and x2 represent the desired position and actual position of the hydraulic cylinder, respectively, and F d F and F represent the input force of the virtual controller and the actual driving force of the hydraulic cylinder, respectively. e1 represents the outer ring position tracking error and e2 represents the inner ring force tracking error.

[0067] According to Lyapunov's stability theory, the input force F of the virtual controller is obtained. d And the actual valve core input u is:

[0068]

[0069] The parameters are explained by formulas (4), (5), and (6). The feedback gain parameter k is adjusted accordingly. p k v k f This ensures that position tracking meets control performance indicators.

[0070] 2) Schematic diagram of the semi-physical simulation platform for valve-controlled hydraulic cylinders as shown below. Figure 1As shown, the system consists of a host computer, a target controller, sensors, and a valve-controlled hydraulic cylinder test bench. The host computer, a standard PC, is used for designing, compiling, and downloading the Simulink simulation model, as well as displaying and saving experimental data. The development environment is MATLAB 2017b / Simulink Real-Time, and the compiler is Microsoft Visual Studio 2017. Furthermore, an Advantech EPC3086 industrial PC is used as the target controller, running a real-time operating system to improve the system's real-time control performance. The data acquisition card built into the target computer is an Advantech PCI1716, expanding to 16 AI channels, 2 AO channels, and 16 DIO channels for signal acquisition and transmission.

[0071] The host computer and the target controller are connected via a network cable, configured with IP addresses and gateways, and communicate within the local area network using the TCP / IP protocol. The host computer contains a Simulink model built in the MATLAB / Simulink environment. After being compiled on the host computer, the model is downloaded to the target machine and runs on the system built with the target machine's real-time kernel.

[0072] The test bench's sensors consist of a hydraulic cylinder piston rod position / speed (position differential) sensor, a pump outlet pressure sensor, a return oil port pressure sensor, a hydraulic cylinder A port pressure sensor, and a hydraulic cylinder B port pressure sensor. The sensor signal type is 4-20mA, which is converted to ±10V type suitable for PCI1716 by a signal conditioner.

[0073] The valve-controlled hydraulic cylinder test bench provides a physical foundation for position tracking control experiments. The hydraulic cylinder has a cylinder diameter of 160mm, a rod diameter of 110mm, and a stroke of 800mm. It has a built-in displacement sensor. The directional valve is an electro-hydraulic proportional valve with a flow capacity ≥100L / min and a frequency response >35Hz. The P, T, A, and B ports of the directional valve are pressure measurement points, and the maximum system pressure is 350bar.

[0074] 3) Run a hardware-in-the-loop simulation platform to conduct open-loop parameter identification experiments for the valve-controlled hydraulic cylinder system. Specific steps include:

[0075] A. Determine the system identification parameters and design the open-loop identification excitation signal.

[0076] Based on equation (4) and the manufacturer's information on the test bench components, the valve orifice flow gain coefficient c is selected. k (k=1,2,3,4), effective bulk modulus β, equivalent load mass m, and viscous friction coefficient b are selected as the parameters to be identified. For a typical nonlinear system like a valve-controlled hydraulic cylinder, the characteristics at various amplitudes and frequencies should be excited by the excitation signal during parameter identification. Therefore, a chirp signal is chosen as the excitation signal for the identification experiment, such as... Figure 2 As shown.

[0077] B. Establish an open-loop identification Simulink model for hardware-in-the-loop simulation and obtain the operating data of the hardware-in-the-loop simulation hardware platform.

[0078] Open-loop identification of Simulink real-time simulation models, such as Figure 3 As shown in the table below. For sensor data acquisition, the displacement and velocity of the piston rod are recorded using a magnetostrictive sensor built into the cylinder, and the pressure values ​​at ports P, T, A, and B of the valve block are recorded by a pressure sensor. Simultaneously, the valve core input value u is also recorded. For data acquisition settings, a signal sampling frequency of 1kHz is selected, with a transmission period and real-time simulation step size of 1ms. A total of four sets of frequency sweep signals are tested, one of which is used as the data validation set. Specific settings are shown in the table below.

[0079]

[0080]

[0081] C. In terms of data preprocessing, a second-order Butterworth low-pass filter is used to filter the signal, with a cutoff frequency of 2Hz. To improve the accuracy of parameter identification, zero-phase filtering is further added, ensuring that the velocity and acceleration signals obtained through differential processing have no phase delay. Figure 4 As shown.

[0082] D. Parameter Identification: The MATLAB gray box identification function nlgreyest is used to identify the mathematical model of the valve-controlled hydraulic cylinder established in step 1. The measured valve core input signal u, outlet pressure signal Ps, and return port pressure P are used to identify the parameters. T As identification inputs, the hydraulic cylinder piston rod displacement x, velocity v, and hydraulic cylinder port A pressure P are used. A and the pressure P at port B of the hydraulic cylinder B This is used as the model's identification output, and the initial values ​​for the identification parameters are set to [β,c1,c2,c3,c4,m,b]. T =[1e8,1e-7,1e-7,1e-7,1e-7,200,4e5] T Due to lumped disturbance f l The difference is not obvious in actual measurement, therefore, its parameters were not considered in the parameter identification process. Finally, the identified fitting curve is obtained as follows: Figure 5 As shown in the figure, the solid lines represent the actual measured data, and the dashed lines represent the simulation output data of the established model. After weighted averaging of the identification results, the final identification parameters are shown in the table below.

[0083]

[0084] E. To verify the parameters obtained by the identification algorithm, a Chirp experimental measurement signal with an amplitude of ±2.5V was selected as a comparison and verification. The actual measured valve core input signal u, outlet pressure signal Ps, and return port pressure P were compared. T As model input, such Figure 6 As shown in (a), the displacement x, velocity v, and pressure P at port A of the hydraulic cylinder piston rod were obtained through Simulink simulation. A B-port pressure P B Output the data and compare it with the output of the validation set, such as... Figure 6 As shown in (b), the simulation results fit the actual output well, indicating that the identified parameters are highly reliable. They can be used for subsequent controller parameter tuning and control experiments.

[0085] 4) Conduct a hardware-in-the-loop simulation experiment for position tracking control. Obtain the position tracking controller through the mathematical model of the valve-controlled hydraulic cylinder system after parameter identification, and select the controller parameter k. p =2400,

[0086] k f =200. A traditional PID control was used for comparison; the PID gain was tuned experimentally, and k was selected. p =350, k i =1.5, k d =1.5. The position tracking reference signal is y = 0.5 + 0.1sin(2πt / T) (m), with a period T = 20s for the experiment. The sampling frequency is 1kHz, and the controller transmission period is 30ms. The system parameters are shown in the table below.

[0087]

[0088] The real-time simulation model of the controller is compiled to generate controller code, which is then downloaded from the host computer to the target controller. The operating data of the valve-controlled hydraulic cylinder test bench is recorded to obtain the position tracking control effect, as shown below. Figure 7 As shown in (b). It can be seen that, compared to... Figure 7 In (a), the PID control based on the valve-controlled hydraulic cylinder model of the position tracking controller has a good tracking effect with a tracking error of less than 2%, which effectively improves the control accuracy of the boom electro-hydraulic drive system.

[0089] In summary, this invention addresses the problems of long on-site testing cycles, high costs, and significant safety risks associated with boom motion control algorithms by establishing a valve-controlled hydraulic cylinder test bench to simulate the operation of the electro-hydraulic drive system of an engineering robot boom under different working conditions. Simultaneously, using a MATLAB / Simulink real-time simulation model as the software foundation, it enables rapid development, deployment, and verification of control algorithms, improving controller design quality and resolving issues such as long controller development cycles and high costs.

[0090] The above content is merely a technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. A hardware-in-the-loop simulation method for the electro-hydraulic drive control system of an engineering robot boom, characterized in that, Includes the following steps: 1) Establish a mathematical model of the valve-controlled hydraulic cylinder of the boom electro-hydraulic drive system and design a position tracking control algorithm model; The establishment of the mathematical model for the valve-controlled hydraulic cylinder of the boom electro-hydraulic drive system includes: A mathematical model of the valve-controlled hydraulic cylinder of the boom electro-hydraulic drive system is established based on the hydraulic cylinder flow continuity equation, force balance equation, and valve orifice flow equation. 2) Establish a hardware platform for semi-physical simulation, which includes a host computer, a target machine controller, sensors, and a valve-controlled hydraulic cylinder test bench; 3) Identify the open-loop parameters of the valve-controlled hydraulic cylinder system based on a hardware-in-the-loop simulation platform, and verify the accuracy of parameter identification through simulation models; 4) Conduct hardware-in-the-loop (HIL) simulation experiments for position tracking control to analyze and verify the effectiveness of position tracking control. The force balance equation is as follows: Where x is the displacement of the valve-controlled hydraulic cylinder, m is the equivalent mass of the piston rod and load, b represents the coefficient of viscous friction, F is the driving force applied by the valve-controlled hydraulic cylinder to the system, and f l The lumped disturbance term in the force balance equation is composed of parameter uncertainty, time-varying external load disturbance, and nonlinear friction modeling error; P1 and P2 are the pressures of the rodless and rod chambers of the hydraulic cylinder, respectively; A1 and A2 are the effective working areas of the rodless and rod chambers of the hydraulic cylinder, respectively. The design position tracking control algorithm model includes: The position tracking control algorithm model is designed as a cascaded controller containing an outer loop position controller and an inner loop force controller. Based on the position tracking error, the virtual input signal of the inner loop force controller is obtained from the outer loop position controller, and then the actual valve core input signal is obtained through the inner loop force controller. The error function is defined as follows: Where e1 represents the outer ring position tracking error, e2 represents the inner ring force tracking error, and x 1d x1 and x2 represent the desired position and actual position of the hydraulic cylinder, respectively, and F d Input for the virtual controller; According to Lyapunov stability theory, the virtual controller input F is obtained. d And the actual valve core input u is: Where x2 is the speed of the hydraulic cylinder, which is determined by adjusting the feedback gain parameter k. p k v k f This ensures that position tracking meets control performance indicators, β e For the effective bulk modulus, V1 = V 10 +A1x and V2 = V 20 -A2x represent the effective volumes of the rodless chamber and the rod chamber of the hydraulic cylinder, respectively. V 10 and V 20 x1 represents the initial volume of the rodless chamber, the rod chamber, and the connecting pipe, respectively, and x2 represents the speed of the hydraulic cylinder.

2. The method according to claim 1, characterized in that, The host computer is based on Simulink to design, compile, and download the simulation model, and displays and saves the data during the experiment; the target machine controller runs a real-time operating system for the acquisition, calculation, transmission, and uploading of experimental data; the valve-controlled hydraulic cylinder test bench is used to simulate the actual working state of the boom electro-hydraulic drive system under engineering operation conditions.

3. The method according to claim 1, characterized in that, The identification of open-loop parameters of the valve-controlled hydraulic cylinder system based on a hardware-in-the-loop simulation platform includes: A. Determine the system identification parameters and design the open-loop identification excitation signal; B. Establish an open-loop identification Simulink model for hardware-in-the-loop simulation and obtain the operating data of the hardware-in-the-loop simulation hardware platform; C. Zero-phase low-pass filtering is used to preprocess the operating data to obtain hydraulic cylinder piston rod position, speed, pump outlet pressure, return oil port pressure, hydraulic cylinder A port pressure, and hydraulic cylinder B port pressure signals without phase difference. D. The parameters of the mathematical model of the valve-controlled hydraulic cylinder are identified using the MATLAB gray box identification function, and the model parameter identification results are obtained.

4. The method according to claim 1, characterized in that, The implementation of hardware-in-the-loop simulation experiments for position tracking control, and the analysis and verification of the position tracking control effect, include: The position tracking controller is obtained based on the mathematical model of the valve-controlled hydraulic cylinder system after parameter identification. The controller code is compiled and downloaded from the host computer to the target machine controller to record the operating data of the valve-controlled hydraulic cylinder test bench.

5. The method according to claim 1, characterized in that, The continuity equation for the flow rate of the valve-controlled hydraulic cylinder is as follows: Where Q1 and Q2 are the valve orifice flow rates of the rodless chamber and rod chamber of the hydraulic cylinder.

6. The method according to claim 5, characterized in that, The valve orifice flow equation is: Where c1, c2, c3, and c4 are the gain coefficients of the electro-hydraulic proportional valve, determined by the shape and size of the valve orifice, P S To alleviate oil export pressure, P T This refers to the pressure at the return oil port.

7. The method according to claim 1, characterized in that, The open-loop parameters of the valve-controlled hydraulic cylinder system are identified based on a hardware-in-the-loop simulation platform. The open-loop parameters include at least one of the following: bulk modulus of elasticity, valve port gain coefficient, effective load, and viscous friction coefficient.

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