A Synchronization Control Method Based on Hydraulic Cylinder Displacement

Abstract

This invention relates to the field of hydraulic cylinder control technology, and discloses a synchronous control method based on hydraulic cylinder displacement. The method includes: acquiring the independent displacement signal and independent working pressure signal of each hydraulic cylinder in a parallel system; generating a global target displacement value based on a pre-set displacement-time continuous function and calculating the real-time displacement deviation value of the independent displacement signal of each hydraulic cylinder; generating a dynamic compensation coefficient corresponding to each hydraulic cylinder based on the real-time displacement deviation value of each hydraulic cylinder using an adaptive proportional-integral algorithm; independently adjusting the opening command value of the proportional flow valve corresponding to each hydraulic cylinder according to a weighted allocation rule based on the dynamic compensation coefficient of each hydraulic cylinder; until the absolute value of the deviation between the real-time displacement of all hydraulic cylinders and the global target displacement value is less than a preset deviation threshold. This invention can achieve more precise synchronous control of hydraulic cylinders, ensuring high-precision operation, while rationally utilizing the hydraulic system's oil supply capacity to meet the needs of high-precision operating equipment.

Description

Technical Field

[0001] This invention relates to the field of hydraulic cylinder control technology, and in particular to a synchronous control method based on hydraulic cylinder displacement. Background Technology

[0002] In the field of hydraulic systems, the synchronous control of hydraulic cylinders has always been a critical issue. Existing cylinder control methods mostly employ speed synchronization or pressure synchronization. However, these methods have many shortcomings in practical applications. Speed ​​synchronization is easily affected by load changes. When the loads on the cylinders differ, even with the same speed setting, the cylinder with the heavier load will experience obstructed movement, leading to differences in displacement between the cylinders and making precise synchronization impossible. Pressure synchronization control places extremely high demands on the accuracy and response speed of the system's pressure sensors. Furthermore, in multi-cylinder parallel systems, pressure transmission exhibits lag, making it difficult to accurately control the synchronization of each cylinder in real time. In addition, these traditional methods show a significant decrease in synchronization accuracy when facing complex operating conditions, such as frequent cylinder starts and stops or sudden load changes, failing to meet the requirements of high-precision operating equipment.

[0003] Therefore, there is an urgent need to provide a technical solution to address the above problems. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention provides a synchronous control method based on cylinder displacement.

[0005] In a first aspect, the present invention provides a synchronous control method based on cylinder displacement, the technical solution of which is as follows:

[0006] S1. Obtain the independent displacement signal and independent working pressure signal corresponding to each cylinder in the parallel cylinder system; wherein, the parallel cylinder system is driven by a hydraulic system, and the hydraulic system provides hydraulic oil to each cylinder through an independent proportional flow valve;

[0007] S2. Based on a pre-defined displacement-time continuous function, generate a global target displacement value, and calculate the real-time displacement deviation value corresponding to the independent displacement signal of each cylinder according to the global target displacement value.

[0008] S3. Based on the real-time displacement deviation value corresponding to each hydraulic cylinder, a dynamic compensation coefficient corresponding to each hydraulic cylinder is generated by an adaptive proportional-integral algorithm; wherein, the integral time constant of the adaptive proportional-integral algorithm is dynamically adjusted based on the load change rate of the corresponding hydraulic cylinder, and the load change rate is calculated by the pressure change gradient of the independent working pressure signal of the corresponding hydraulic cylinder per unit time.

[0009] S4. Based on the dynamic compensation coefficient of each cylinder, independently adjust the opening command value of the proportional flow valve corresponding to each cylinder according to the weight allocation rule. The weight allocation rule is: the cylinder with the largest absolute value of real-time displacement deviation gets the maximum compensation flow first, and the remaining flow is allocated to the other cylinders according to the deviation ratio.

[0010] S5. Repeat steps S1 to S4 until the absolute value of the deviation between the real-time displacement of all cylinders and the global target displacement value is less than the preset deviation threshold.

[0011] The total pressure parameter of the hydraulic system is a preset upper limit value of the system oil supply pressure. Pressure protection is triggered only when the total demand flow of the proportional flow valve exceeds the oil supply capacity of the hydraulic system, and the response priority of the pressure protection is lower than that of the displacement synchronization control.

[0012] The beneficial effects of the synchronous control method based on cylinder displacement of the present invention are as follows:

[0013] The method of this invention can effectively reduce the impact of load changes and complex working conditions on the synchronization accuracy of hydraulic cylinders, achieve more precise hydraulic cylinder synchronization control, ensure high-precision operation, and make reasonable use of the hydraulic system's oil supply capacity. It only triggers pressure protection with lower priority when the total demand flow exceeds the oil supply capacity, thereby improving the reliability and stability of the hydraulic system, reducing system energy consumption, and meeting the needs of high-precision operating equipment.

[0014] Based on the above scheme, the synchronous control method based on cylinder displacement of the present invention can be further improved as follows.

[0015] Furthermore, the step of generating a global target displacement value based on a pre-defined displacement-time continuity function further includes:

[0016] The displacement-time continuous function s(y) is pre-defined according to the operational requirements, and the current time t is... k The current time t is generated by inputting the displacement-time continuous function s(t). k The global target displacement value s target (t k )=s(t k ).

[0017] Furthermore, the step of calculating the real-time displacement deviation value corresponding to the independent displacement signal of each cylinder based on the global target displacement value further includes:

[0018] Obtain the value of the i-th cylinder at the current time t. k The actual displacement value s corresponding to the independent displacement signal i (t k ), and combined with the current time t kThe global target displacement value s target (t k ), calculate the real-time displacement deviation value e corresponding to the i-th cylinder. i (t k This process continues until the real-time displacement deviation value for each cylinder is calculated; the expression for calculating the real-time displacement deviation value is: e i (t k ) = s i (t k )-s target (t k ).

[0019] Furthermore, the step of generating the dynamic compensation coefficient corresponding to the i-th cylinder based on the real-time displacement deviation value corresponding to the i-th cylinder using an adaptive proportional-integral algorithm further includes:

[0020] Obtain the value of the i-th cylinder at the current time t. k The independent working pressure signal corresponds to the hydraulic cylinder working pressure p i (t k ), and calculate the value of the i-th cylinder at the current time t. k Load change rate γ i (t k Its expression is:

[0021]

[0022] In the formula, Δt represents the time interval of the control cycle, t k-1 =t k -Δt, p i (t k-1 ) represents the current time t k The working pressure of the hydraulic cylinder in the previous control cycle;

[0023] According to the i-th cylinder at the current time t k Load change rate γ i (t k Adjust the integration time constant T in the adaptive proportional-integral algorithm. i (t k Its expression is:

[0024]

[0025] In the formula, T base β represents the baseline integral time constant, preset according to system stability requirements; β represents the load change rate adjustment coefficient, used to control the sensitivity of the integral time constant to load changes.

[0026] Based on the real-time displacement deviation value e corresponding to the i-th cylinderi (t k ) and the adjusted integral time constant T i (t k The dynamic compensation coefficient K for the i-th cylinder is calculated using the adaptive proportional-integral algorithm. i (t k Its expression is:

[0027]

[0028] In the formula, K p K represents the preset proportional gain coefficient. I (t k The ) represents the dynamic integral gain coefficient, which is determined by the adjusted integral time constant T. i (t k )Sure, m represents the index variable of the time step, m∈[0,k].

[0029] Furthermore, the step of independently adjusting the opening command value of the proportional flow valve corresponding to each hydraulic cylinder according to the dynamic compensation coefficient of each hydraulic cylinder and the weighting allocation rule further includes:

[0030] Obtain the absolute value of the real-time displacement deviation for each hydraulic cylinder. Iterate through the absolute values ​​of the real-time displacement deviation for all hydraulic cylinders and determine the index j of the hydraulic cylinder with the largest absolute value of the real-time displacement deviation. Its expression is:

[0031]

[0032] In the formula, |e i (t k )| represents the absolute value of the real-time displacement deviation corresponding to the i-th cylinder, and N represents the number of cylinders in the parallel cylinder system;

[0033] Calculate the sum of the absolute values ​​of the real-time displacement deviations of all cylinders, and calculate the weight of the cylinder with the largest absolute value of the real-time displacement deviation, as well as the weight allocation of the remaining cylinders.

[0034] The expression for the cylinder weight that calculates the absolute value of the maximum real-time displacement deviation is as follows:

[0035]

[0036] In the formula, w j This represents the weight of the j-th cylinder, i.e., the cylinder with the largest absolute value of real-time displacement deviation.

[0037] The expression for calculating the weight of the remaining hydraulic cylinders is as follows:

[0038]

[0039] Based on the dynamic compensation coefficient and cylinder weight of each cylinder, the opening command value of the proportional flow valve corresponding to each cylinder is calculated, and its expression is as follows:

[0040]

[0041] In the formula, U i (t k U represents the opening command value of the proportional flow valve corresponding to the i-th cylinder. max This indicates the maximum opening command value for the proportional flow valve.

[0042] Furthermore, the expression for the displacement-time continuous function s(t) is:

[0043] s(t)=a0+a1t+a2t 2 +a3t 3 +a4t 4 +a5t 5

[0044] In the formula, a0, a1, a2, a3, a4 and a5 are determined according to the speed, acceleration and jerk boundary conditions corresponding to the operation requirements.

[0045] Secondly, the present invention provides a synchronous control system based on cylinder displacement, the technical solution of which is as follows:

[0046] The acquisition module is used to acquire the independent displacement signal and independent working pressure signal of each cylinder in the parallel cylinder system; wherein, the parallel cylinder system is driven by a hydraulic system, and the hydraulic system supplies hydraulic oil to each cylinder through an independent proportional flow valve;

[0047] The calculation module is used to generate a global target displacement value based on a pre-set displacement-time continuous function, and to calculate the real-time displacement deviation value corresponding to the independent displacement signal of each cylinder according to the global target displacement value.

[0048] The generation module is used to generate dynamic compensation coefficients for each hydraulic cylinder based on the real-time displacement deviation value corresponding to each hydraulic cylinder and through an adaptive proportional-integral algorithm. The integral time constant of the adaptive proportional-integral algorithm is dynamically adjusted based on the load change rate of the corresponding hydraulic cylinder, and the load change rate is calculated by the pressure change gradient of the independent working pressure signal of the corresponding hydraulic cylinder per unit time.

[0049] The control module is used to independently adjust the opening command value of the proportional flow valve corresponding to each cylinder according to the dynamic compensation coefficient of each cylinder and the weight allocation rule. The weight allocation rule is: the cylinder with the largest absolute value of real-time displacement deviation gets the maximum compensation flow first, and the remaining flow is allocated to the other cylinders according to the deviation ratio.

[0050] The loop module is used to repeatedly call the acquisition module to the control module until the absolute value of the deviation between the real-time displacement of all cylinders and the global target displacement value is less than the preset deviation threshold.

[0051] The total pressure parameter of the hydraulic system is a preset upper limit value of the system oil supply pressure. Pressure protection is triggered only when the total demand flow of the proportional flow valve exceeds the oil supply capacity of the hydraulic system, and the response priority of the pressure protection is lower than that of the displacement synchronization control.

[0052] The beneficial effects of the synchronous control system based on cylinder displacement of the present invention are as follows:

[0053] The system of this invention can effectively reduce the impact of load changes and complex working conditions on the synchronization accuracy of hydraulic cylinders, achieve more precise hydraulic cylinder synchronization control, ensure high-precision operation, and at the same time make reasonable use of the hydraulic system's oil supply capacity, triggering low-priority pressure protection only when the total demand flow exceeds the oil supply capacity, thereby improving the reliability and stability of the hydraulic system operation, reducing system energy consumption, and meeting the needs of high-precision operating equipment.

[0054] The above description is merely an overview of the technical solution of the present invention. In order to better understand the technical means of the present invention and to implement it in accordance with the contents of the specification, and in order to make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments of the present invention are described below. Attached Figure Description

[0055] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without any creative effort.

[0056] The accompanying drawings are for illustrative purposes only and are not intended to limit the invention. Furthermore, the same reference numerals denote the same parts throughout the drawings. In the drawings:

[0057] Figure 1 This is a schematic flowchart of an embodiment of the synchronous control method based on cylinder displacement according to the present invention.

[0058] Figure 2This is a schematic diagram of an embodiment of a synchronous control system based on cylinder displacement according to the present invention. Detailed Implementation

[0059] Exemplary embodiments of the invention will now be described in more detail with reference to the accompanying drawings. Although exemplary embodiments of the invention are shown in the drawings, it should be understood that the invention may be implemented in various forms and should not be limited to the embodiments set forth herein.

[0060] Figure 1 A schematic flowchart illustrating an embodiment of a synchronous control method based on cylinder displacement provided by the present invention is shown. Figure 1 As shown, it includes the following steps:

[0061] S1. Obtain the independent displacement signal and independent working pressure signal corresponding to each cylinder in the parallel cylinder system; wherein, the parallel cylinder system is driven by a hydraulic system, and the hydraulic system provides hydraulic oil to each cylinder through an independent proportional flow valve;

[0062] S2. Based on a pre-defined displacement-time continuous function, generate a global target displacement value, and calculate the real-time displacement deviation value corresponding to the independent displacement signal of each cylinder according to the global target displacement value.

[0063] S3. Based on the real-time displacement deviation value corresponding to each hydraulic cylinder, a dynamic compensation coefficient corresponding to each hydraulic cylinder is generated by an adaptive proportional-integral algorithm; wherein, the integral time constant of the adaptive proportional-integral algorithm is dynamically adjusted based on the load change rate of the corresponding hydraulic cylinder, and the load change rate is calculated by the pressure change gradient of the independent working pressure signal of the corresponding hydraulic cylinder per unit time.

[0064] S4. Based on the dynamic compensation coefficient of each cylinder, independently adjust the opening command value of the proportional flow valve corresponding to each cylinder according to the weight allocation rule. The weight allocation rule is: the cylinder with the largest absolute value of real-time displacement deviation gets the maximum compensation flow first, and the remaining flow is allocated to the other cylinders according to the deviation ratio.

[0065] S5. Repeat steps S1 to S4 until the absolute value of the deviation between the real-time displacement of all cylinders and the global target displacement value is less than the preset deviation threshold.

[0066] The total pressure parameter of the hydraulic system is a preset upper limit value of the system oil supply pressure. Pressure protection is triggered only when the total demand flow of the proportional flow valve exceeds the oil supply capacity of the hydraulic system, and the response priority of the pressure protection is lower than that of the displacement synchronization control.

[0067] In an alternative approach, the step of generating a global target displacement value based on a pre-defined displacement-time continuity function further includes:

[0068] The displacement-time continuous function s(t) is pre-defined according to the operational requirements, and the current time t is... k The current time t is generated by inputting the displacement-time continuous function s(t). k The global target displacement value s tar get (t k )=s(t k ).

[0069] In an optional approach, the step of calculating the real-time displacement deviation value corresponding to the independent displacement signal of each cylinder based on the global target displacement value further includes:

[0070] Obtain the value of the i-th cylinder at the current time t. k The actual displacement value s corresponding to the independent displacement signal i (t k ), and combined with the current time t k The global target displacement value s tar get (t k ), calculate the real-time displacement deviation value e corresponding to the i-th cylinder. i (t k This process continues until the real-time displacement deviation value for each cylinder is calculated; the expression for calculating the real-time displacement deviation value is: e i (t k ) = s i (t k )-s target (t k ).

[0071] In one optional approach, the step of generating the dynamic compensation coefficient corresponding to the i-th cylinder based on the real-time displacement deviation value corresponding to the i-th cylinder using an adaptive proportional-integral algorithm further includes:

[0072] Obtain the value of the i-th cylinder at the current time t. k The independent working pressure signal corresponds to the hydraulic cylinder working pressure p i (t k ), and calculate the value of the i-th cylinder at the current time t. k Load change rate γ i (t k Its expression is:

[0073]

[0074] In the formula, Δt represents the time interval of the control cycle, t k-1 =t k-Δt, p i (t k-1 ) represents the current time t k The working pressure of the hydraulic cylinder in the previous control cycle;

[0075] According to the i-th cylinder at the current time t k Load change rate γ i (t k Adjust the integration time constant T in the adaptive proportional-integral algorithm. i (t k Its expression is:

[0076]

[0077] In the formula, T base β represents the baseline integral time constant, preset according to system stability requirements; β represents the load change rate adjustment coefficient, used to control the sensitivity of the integral time constant to load changes.

[0078] Based on the real-time displacement deviation value e corresponding to the i-th cylinder i (t k ) and the adjusted integral time constant T i (t k The dynamic compensation coefficient K for the i-th cylinder is calculated using the adaptive proportional-integral algorithm. i (t k Its expression is:

[0079]

[0080] In the formula, K p K represents the preset proportional gain coefficient. I (t k The ) represents the dynamic integral gain coefficient, which is determined by the adjusted integral time constant T. i (t k )Sure, m represents the index variable of the time step, m∈[0,k].

[0081] In an optional embodiment, the step of independently adjusting the opening command value of the proportional flow valve corresponding to each hydraulic cylinder according to the dynamic compensation coefficient of each hydraulic cylinder and the weighting allocation rule further includes:

[0082] Obtain the absolute value of the real-time displacement deviation for each hydraulic cylinder. Iterate through the absolute values ​​of the real-time displacement deviation for all hydraulic cylinders and determine the index j of the hydraulic cylinder with the largest absolute value of the real-time displacement deviation. Its expression is:

[0083]

[0084] In the formula, |ei (t k )| represents the absolute value of the real-time displacement deviation corresponding to the i-th cylinder, and N represents the number of cylinders in the parallel cylinder system;

[0085] Calculate the sum of the absolute values ​​of the real-time displacement deviations of all cylinders, and calculate the weight of the cylinder with the largest absolute value of the real-time displacement deviation, as well as the weight allocation of the remaining cylinders.

[0086] The expression for the cylinder weight that calculates the absolute value of the maximum real-time displacement deviation is as follows:

[0087]

[0088] In the formula, w j This represents the weight of the j-th cylinder, i.e., the cylinder with the largest absolute value of real-time displacement deviation.

[0089] The expression for calculating the weight of the remaining hydraulic cylinders is as follows:

[0090]

[0091] Based on the dynamic compensation coefficient and cylinder weight of each cylinder, the opening command value of the proportional flow valve corresponding to each cylinder is calculated, and its expression is as follows:

[0092]

[0093] In the formula, U i (t k U represents the opening command value of the proportional flow valve corresponding to the i-th cylinder. max This indicates the maximum opening command value for the proportional flow valve.

[0094] Specifically, assume a parallel hydraulic cylinder system with three cylinders, whose real-time displacement deviations are: |e1| = 2.0 mm, |e2| = 3.5 mm, and |e3| = 1.5 mm; the cylinder with the largest real-time displacement deviation has an index j = 2, ∑|e| = 7.0 mm, w2 = 3.5 / 7.0 = 0.5, w1 = 0.29, and w3 = 0.21; if K1 = 0.8, K2 = 1.2, K3 = 0.6, and U... max If 100%, then U2 = 60%, U1 = 22.86%, and U3 = 12.86%.

[0095] In an alternative approach, the expression for the displacement-time continuous function s(t) is:

[0096] s(t)=a0+a1t+a2t 2 +a3t 3 +a4t 4 +a5t5

[0097] In the formula, a0, a1, a2, a3, a4 and a5 are determined according to the speed, acceleration and jerk boundary conditions corresponding to the operation requirements.

[0098] The technical solution of this embodiment can effectively reduce the impact of load changes and complex working conditions on the synchronization accuracy of the hydraulic cylinder, achieve more precise hydraulic cylinder synchronization control, ensure high-precision operation, and make reasonable use of the hydraulic system's oil supply capacity. It only triggers pressure protection with lower priority when the total demand flow exceeds the oil supply capacity, thereby improving the reliability and stability of the hydraulic system, reducing system energy consumption, and meeting the needs of high-precision operating equipment.

[0099] Figure 2 A schematic diagram of an embodiment of a synchronous control system based on cylinder displacement provided by the present invention is shown. Figure 2 As shown, the system includes:

[0100] The acquisition module 210 is used to acquire the independent displacement signal and independent working pressure signal corresponding to each cylinder in the parallel cylinder system; wherein, the parallel cylinder system is driven by a hydraulic system, and the hydraulic system provides hydraulic oil to each cylinder through an independent proportional flow valve;

[0101] The calculation module 220 is used to generate a global target displacement value based on a pre-set displacement-time continuous function, and to calculate the real-time displacement deviation value corresponding to the independent displacement signal of each cylinder according to the global target displacement value.

[0102] The generation module 230 is used to generate dynamic compensation coefficients for each hydraulic cylinder based on the real-time displacement deviation value corresponding to each hydraulic cylinder and through an adaptive proportional-integral algorithm; wherein, the integral time constant of the adaptive proportional-integral algorithm is dynamically adjusted based on the load change rate of the corresponding hydraulic cylinder, and the load change rate is calculated by the pressure change gradient of the independent working pressure signal of the corresponding hydraulic cylinder per unit time.

[0103] Control module 240 is used to independently adjust the opening command value of the proportional flow valve corresponding to each cylinder according to the dynamic compensation coefficient of each cylinder and the weight allocation rule. The weight allocation rule is: the cylinder with the largest absolute value of real-time displacement deviation is given priority to obtain the maximum compensation flow, and the remaining flow is allocated to the other cylinders according to the deviation ratio.

[0104] The loop module 250 is used to repeatedly call the acquisition module 210 to the control module 240 until the absolute value of the deviation between the real-time displacement of all cylinders and the global target displacement value is less than the preset deviation threshold.

[0105] The total pressure parameter of the hydraulic system is a preset upper limit value of the system oil supply pressure. Pressure protection is triggered only when the total demand flow of the proportional flow valve exceeds the oil supply capacity of the hydraulic system, and the response priority of the pressure protection is lower than that of the displacement synchronization control.

[0106] The technical solution of this embodiment can effectively reduce the impact of load changes and complex working conditions on the synchronization accuracy of the hydraulic cylinder, achieve more precise hydraulic cylinder synchronization control, ensure high-precision operation, and make reasonable use of the hydraulic system's oil supply capacity. It only triggers pressure protection with lower priority when the total demand flow exceeds the oil supply capacity, thereby improving the reliability and stability of the hydraulic system, reducing system energy consumption, and meeting the needs of high-precision operating equipment.

[0107] Furthermore, the system provided in the above embodiments is only illustrated by the division of the above functional modules. In practical applications, the above functions can be assigned to different functional modules as needed, that is, the system can be divided into different functional modules according to the actual situation to complete all or part of the functions described above. In addition, the system and method embodiments provided in the above embodiments belong to the same concept, and their specific implementation process can be found in the method embodiments, which will not be repeated here.

[0108] The above description is merely a preferred embodiment of the present invention and an explanation of the technical principles employed. Those skilled in the art should understand that the scope of disclosure in this invention is not limited to technical solutions formed by specific combinations of the above-described technical features, but should also cover other technical solutions formed by arbitrary combinations of the above-described technical features or their equivalents without departing from the above-described concept. For example, technical solutions formed by substituting the above features with (but not limited to) technical features with similar functions disclosed in this invention.

[0109] It should be noted that the terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and represent a limitation on a specific order or sequence. Where appropriate, the order of use for similar objects can be interchanged so that the embodiments of this application described herein can be implemented in an order other than that shown or described.

[0110] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A synchronization control method based on cylinder displacement, characterized by, The method comprises: S1, acquiring independent displacement signals and independent working pressure signals corresponding to each oil cylinder in the oil cylinder parallel system; wherein the oil cylinder parallel system is driven by a hydraulic system, and the hydraulic system provides hydraulic oil for each oil cylinder through independent proportional flow valves; S2, generating a global target displacement value based on a pre-set displacement-time continuous function, and calculating real-time displacement deviation values corresponding to the independent displacement signals of each oil cylinder according to the global target displacement value; S3, generating dynamic compensation coefficients corresponding to each oil cylinder according to the real-time displacement deviation values corresponding to each oil cylinder and through an adaptive proportional integral algorithm; wherein an integral time constant of the adaptive proportional integral algorithm is dynamically adjusted based on a load change rate of the corresponding oil cylinder, and the load change rate is calculated through a pressure change gradient of the independent working pressure signal of the corresponding oil cylinder within a unit time; S4, independently adjusting opening command values of the proportional flow valves corresponding to each oil cylinder according to the dynamic compensation coefficients of each oil cylinder and a weight distribution rule, wherein the weight distribution rule is that an oil cylinder with the largest real-time displacement deviation absolute value is given the largest compensation flow in priority, and the remaining oil cylinders are allocated the remaining flow in proportion to the deviation; S5, cyclically executing steps S1 to S4 until the absolute values of the deviations of the real-time displacements of all oil cylinders from the global target displacement value are all less than a pre-set deviation threshold; Wherein, the total pressure parameter of the hydraulic system is a pre-set system oil supply pressure upper limit value, the pressure protection is triggered only when the total demand flow of the proportional flow valves exceeds the oil supply capacity of the hydraulic system, and the response priority of the pressure protection is lower than that of the displacement synchronization control.

2. The synchronous control method based on the cylinder displacement according to claim 1, wherein The step of generating a global target displacement value based on a pre-set displacement-time continuous function further comprises: The displacement-time continuous function s(t) is set in advance according to the job requirement, and the current time t k is input to the displacement-time continuous function s(t) to generate the global target displacement value s k (t target ) = s(t k ) of the current time t k .

3. The synchronous control method based on the cylinder displacement according to claim 2, wherein The step of calculating real-time displacement deviation values corresponding to the independent displacement signals of each oil cylinder according to the global target displacement value further comprises: Obtain the value of the i-th cylinder at the current time t. k The actual displacement value s corresponding to the independent displacement signal i (t k ), and combined with the current time t k The global target displacement value s target (t k ), calculate the real-time displacement deviation value e corresponding to the i-th cylinder. i (t k This process continues until the real-time displacement deviation value for each cylinder is calculated; the expression for calculating the real-time displacement deviation value is: e i (t k ) = s i (t k )-s target (t k ).

4. The synchronous control method based on the cylinder displacement according to claim 3, characterized by, The step of generating a dynamic compensation coefficient corresponding to the i-th oil cylinder according to the real-time displacement deviation value corresponding to the i-th oil cylinder and through an adaptive proportional integral algorithm further comprises: Obtain the value of the i-th cylinder at the current time t. k The independent working pressure signal corresponds to the hydraulic cylinder working pressure p i (t k ), and calculate the value of the i-th cylinder at the current time t. k Load change rate γ i (t k Its expression is: In the formula, Δt represents the time interval of the control period, t k-1 = t k - Δt, p i (t k-1 ) represents the working pressure of the oil cylinder in the previous control period at the current time t k ; According to the load change rate γ of the i-th oil cylinder at the current time t k , the integral time constant T i (t k ) in the adaptive proportional integral algorithm is adjusted, and its expression is: i (t k ) In the formula, T base represents the reference integral time constant, which is preset according to the system stability requirement; and β represents the load change rate adjustment coefficient, which is used to control the sensitivity of the integral time constant to the load change. According to the real-time displacement deviation value e of the i-th oil cylinder i (t k ) and the adjusted integral time constant T i (t k ), the dynamic compensation coefficient K i (t k ) corresponding to the i-th oil cylinder is calculated by the adaptive proportional integral algorithm, and the expression is: where K p represents a preset proportional gain coefficient; K I (t k ) represents a dynamic integral gain coefficient determined by the adjusted integral time constant T i (t k ) and the preset proportional gain coefficient K m represents an index variable of time steps, m ∈ [0, k].

5. The method of synchronised control based on ram displacement according to claim 4, wherein, The step of independently adjusting the opening command values of the proportional flow valves corresponding to each oil cylinder according to the dynamic compensation coefficients of each oil cylinder and a weight distribution rule further comprises: Obtaining real-time displacement deviation absolute values corresponding to each oil cylinder, traversing the real-time displacement deviation absolute values of all oil cylinders, and determining an oil cylinder index j with the largest real-time displacement deviation absolute value, which is expressed as: In the formula, |e i (t k ) | represents the absolute value of the real-time displacement deviation corresponding to the i-th oil cylinder, and N represents the number of oil cylinders in the oil cylinder interlocking system. Calculating the sum of the real-time displacement deviation absolute values of all oil cylinders, and calculating the oil cylinder weight of the oil cylinder with the largest real-time displacement deviation absolute value and the weight distribution of the remaining oil cylinders; Wherein, the expression for calculating the oil cylinder weight of the oil cylinder with the largest real-time displacement deviation absolute value is: In the formula, w j represents the weight of the jth oil cylinder, that is, the weight of the oil cylinder with the largest absolute value of real-time displacement deviation Wherein, the expression for calculating the weight distribution of the remaining oil cylinders is: According to the dynamic compensation coefficients of each oil cylinder and the oil cylinder weight, the opening command values of the proportional flow valves corresponding to each oil cylinder are calculated, which is expressed as: In the formula, U i (t k ) represents the opening command value of the proportional flow valve corresponding to the i-th oil cylinder, U max represents the maximum opening command value of the proportional flow valve.

6. The synchronization control method based on the displacement of the oil cylinder according to any one of claims 2 to 5, characterized by, The expression of the displacement-time continuous function s(t) is: s(t) = a0+ a1t + a2t 2 + a3t 3 + a4t 4 + a5t 5 In the formula, a0, a1, a2, a3, a4 and a5 are determined according to the speed, acceleration and jerk boundary conditions corresponding to the operation demand.

7. A synchronous control system based on cylinder displacement, characterized by, The system comprises: An acquisition module is configured to acquire an independent displacement signal and an independent working pressure signal corresponding to each oil cylinder in a cylinder parallel system; the cylinder parallel system is driven by a hydraulic system, and the hydraulic system provides hydraulic oil for each oil cylinder through an independent proportional flow valve; A calculation module is configured to generate a global target displacement value based on a pre-set displacement-time continuous function, and calculate a real-time displacement deviation value corresponding to the independent displacement signal of each oil cylinder according to the global target displacement value; A generation module is configured to generate a dynamic compensation coefficient corresponding to each oil cylinder according to the real-time displacement deviation value corresponding to each oil cylinder and through an adaptive proportional integral algorithm; an integral time constant of the adaptive proportional integral algorithm is dynamically adjusted based on a load change rate of the corresponding oil cylinder, and the load change rate is calculated through a pressure change gradient of the independent working pressure signal of the corresponding oil cylinder in a unit time; A control module is configured to independently adjust an opening instruction value of the proportional flow valve corresponding to each oil cylinder according to the dynamic compensation coefficient of each oil cylinder and according to a weight distribution rule; the weight distribution rule is that an oil cylinder with a maximum real-time displacement deviation absolute value is given a maximum compensation flow in priority, and the remaining oil cylinders are given a remaining flow in proportion to the deviation; A cycle module is configured to cyclically call the acquisition module to the control module until the absolute value of the deviation between the real-time displacement of all oil cylinders and the global target displacement value is less than a pre-set deviation threshold. The total pressure parameter of the hydraulic system is a pre-set system oil supply upper limit value, pressure protection is triggered only when the total demand flow of the proportional flow valve exceeds the oil supply capacity of the hydraulic system, and the response priority of the pressure protection is lower than that of displacement synchronization control.

8. The synchronous control system based on the displacement of the oil cylinder according to claim 7, characterized by, The calculation module is specifically configured to: The displacement-time continuous function s(t) is set in advance according to the job requirement, and the current time t k is input to the displacement-time continuous function s(t) to generate the global target displacement value s k of the current time t target (t k ) = s(t k ).

9. The synchronous control system based on the displacement of the oil cylinder according to claim 8, characterized by, The calculation module is specifically configured to: Obtain the value of the i-th cylinder at the current time t. k The actual displacement value s corresponding to the independent displacement signal i (t k ), and combined with the current time t k The global target displacement value s target (t k ), calculate the real-time displacement deviation value e corresponding to the i-th cylinder. i (t k This process continues until the real-time displacement deviation value for each cylinder is calculated; the expression for calculating the real-time displacement deviation value is: e i (t k ) = s i (t k )-s target (t k ).

10. The synchronous control system based on the displacement of the oil cylinder according to claim 9, characterized by, The generation module is specifically configured to: acquiring the independent working pressure signal of the i-th oil cylinder at the current time t k corresponding to the working pressure p i (t k ) of the i-th oil cylinder, and calculating the load change rate γ i (t k ) of the i-th oil cylinder at the current time t k , which is expressed as: In the formula, Δt represents the time interval of the control period, t k-1 = t k - Δt, p i (t k-1 ) represents the cylinder working pressure of the previous control period at the current time t k . According to the load change rate γ of the i-th oil cylinder at the current time t k i (t k ), the integral time constant T in the adaptive proportional integral algorithm is adjusted i (t k ), and the expression is:​ In the formula, T base represents the reference integral time constant, which is preset according to the system stability requirement; and β represents a load change rate adjustment coefficient, which is used to control the sensitivity of the integral time constant to the load change. According to the real-time displacement deviation value e of the i-th oil cylinder i (t k ) and the adjusted integral time constant T i (t k ), the dynamic compensation coefficient K i (t k ) corresponding to the i-th oil cylinder is calculated by the adaptive proportional integral algorithm, and the expression is: where K p represents a preset proportional gain coefficient; K I (t k ) represents a dynamic integral gain coefficient determined by the adjusted integral time constant T i (t k ) and the time step size Δt, m represents an index variable of time steps, m ∈ [0, k].

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