Synchronous control method based on oil cylinder displacement

Abstract

The invention relates to the technical field of oil cylinder control, and discloses an oil cylinder displacement-based synchronous control method, which comprises the following steps of: acquiring an independent displacement signal and an independent working pressure signal of each oil cylinder in an oil cylinder parallel system; based on a preset displacement-time continuous function, generating a global target displacement value and calculating a real-time displacement deviation value of the independent displacement signal of each oil cylinder; according to the real-time displacement deviation value of each oil cylinder, a dynamic compensation coefficient corresponding to each oil cylinder is generated through a self-adaptive proportional-integral algorithm; according to the dynamic compensation coefficient of each oil cylinder, independently adjusting an opening instruction value of a proportional flow valve corresponding to each oil cylinder according to a weight distribution rule; the absolute values of the deviations between the real-time displacements of all the oil cylinders and the global target displacement value are all smaller than a preset deviation threshold value. Synchronous control over the oil cylinders can be achieved more accurately, high-precision operation is guaranteed, meanwhile, the oil supply capacity of a hydraulic system is reasonably utilized, and the requirements of high-precision operation equipment are met.

Description

Technical Field

[0001] The present invention relates to the technical field of oil cylinder control, and particularly to a synchronous control method based on the displacement of an oil cylinder. Background Art

[0002] In the field of hydraulic systems, the synchronous control of oil cylinders has always been a key issue. Existing oil cylinder control methods mostly adopt methods such as speed synchronization or pressure synchronization. However, these methods have many defects in practical applications. The speed synchronization method is easily affected by load changes. When the loads borne by oil cylinders are different, even if the speed settings are the same, the movement of the oil cylinder with a large load will be blocked, resulting in differences in the displacements of different oil cylinders and unable to achieve precise synchronization. Pressure synchronization control has extremely high requirements for the accuracy and response speed of the system pressure sensor, and in a multi-oil cylinder parallel system, there is a lag in pressure transmission, making it difficult to accurately regulate the synchronization of each oil cylinder in real time. In addition, when facing complex working conditions, such as frequent start and stop of oil cylinders and sudden load changes, the synchronization accuracy of these traditional methods drops significantly and cannot meet the requirements of high-precision operating equipment.

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

[0004] To solve the above technical problems, the present invention provides a synchronous control method based on the displacement of an oil cylinder.

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

[0006] S1. Obtain the independent displacement signal and independent working pressure signal 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 an independent proportional flow valve;

[0007] S2. Generate a global target displacement value based on a pre-set displacement-time continuous function, and calculate the real-time displacement deviation value corresponding to the independent displacement signal of each oil cylinder according to the global target displacement value;

[0008] S3. According to the real-time displacement deviation value corresponding to each oil cylinder, respectively generate a dynamic compensation coefficient corresponding to each oil cylinder 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 oil cylinder, and the load change rate is calculated through the pressure change gradient of the independent working pressure signal of the corresponding oil cylinder within a unit time;

[0009] S4. Independently adjust the opening command value of the proportional flow valve corresponding to each oil cylinder according to the dynamic compensation coefficient of each oil cylinder, where the weight distribution rule is: the oil cylinder with the largest absolute value of the real-time displacement deviation is given the maximum compensation flow first, and the remaining oil cylinders are allocated the remaining flow according to the deviation ratio;

[0010] S5. Loop through steps S1 to S4 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 the preset deviation threshold;

[0011] Among them, the total pressure parameter of the hydraulic system is the preset upper limit value of the system oil supply pressure, and the pressure protection is triggered only when the total required 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 a synchronous control method based on the displacement of an oil cylinder according to the present invention are as follows:

[0013] The method of the present invention can effectively reduce the influence of load changes and complex working conditions on the synchronization accuracy of the oil cylinders, more accurately achieve the synchronous control of the oil cylinders, ensure high-precision operation, and at the same time rationally utilize the oil supply capacity of the hydraulic system. The pressure protection with a lower priority is triggered only when the total required flow exceeds the oil supply capacity, improving the reliability and stability of the operation of the hydraulic system, reducing the system energy consumption, and meeting the requirements of high-precision operation equipment.

[0014] On the basis of the above solution, a synchronous control method based on the displacement of an oil cylinder according to the present invention can also be improved as follows.

[0015] Further, the step of generating the global target displacement value based on the pre-set displacement-time continuous function further includes:

[0016] Preset the displacement-time continuous function s(y) according to the operation requirements, and input the current time t k into the displacement-time continuous function s(t), and generate the global target displacement value s k at the current time t target (t k ) = s(t k ).

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

[0018] Obtain the actual displacement value s k corresponding to the independent displacement signal of the i-th oil cylinder at the current time t i (t k ), and combine it with the current time t kthe global target displacement value s target (t k ) and calculate the real-time displacement deviation value e i (t k ) corresponding to the i-th oil cylinder until the real-time displacement deviation values corresponding to each oil cylinder are calculated; wherein, the expression for calculating the real-time displacement deviation value is: e i (t k ) = s i (t k ) - s target (t k ).

[0019] Further, the step of generating the 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 the adaptive proportional-integral algorithm further includes:

[0020] Obtain the working pressure p k of the oil cylinder corresponding to the independent working pressure signal of the i-th oil cylinder at the current moment t i (t k ), and calculate the load change rate γ k of the i-th oil cylinder at the current moment t i (t k ), and its expression is:

[0021]

[0022] wherein, Δt represents the time interval of the control period, t k-1 = t k - Δt, and p i (t k-1 ) represents the working pressure of the oil cylinder in the previous control period at the current moment t k .

[0023] According to the load change rate γ k of the i-th oil cylinder at the current moment t i (t k ), adjust the integral time constant T i (t k ) in the adaptive proportional-integral algorithm, and its expression is:

[0024]

[0025] wherein, T base represents the reference integral time constant, which is preset according to the system stability requirement; β represents the load change rate adjustment coefficient, which is used to control the sensitivity of the integral time constant to the load change;

[0026] According to the real-time displacement deviation value e corresponding to the i-th oil cylinderi (t k ) and the adjusted integral time constant T i (t k ), calculate and generate the dynamic compensation coefficient K corresponding to the i-th oil cylinder through the adaptive proportional-integral algorithm i (t k ), and its expression is:

[0027]

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

[0029] Further, the step of independently adjusting the opening command value of the proportional flow valve corresponding to each oil cylinder according to the dynamic compensation coefficient of each oil cylinder further includes:

[0030] Obtain the absolute value of the real-time displacement deviation corresponding to each oil cylinder, traverse the absolute values of the real-time displacement deviations of all oil cylinders, and determine the cylinder index j of the maximum 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 oil cylinder, and N represents the number of oil cylinders in the oil cylinder parallel system;

[0033] Calculate the sum of the absolute values of the real-time displacement deviations of all oil cylinders, and calculate the weight of the oil cylinder with the maximum absolute value of the real-time displacement deviation and the weight distribution of the remaining oil cylinders;

[0034] Among them, the expression for calculating the weight of the oil cylinder with the maximum absolute value of the real-time displacement deviation is:

[0035]

[0036] In the formula, w j represents the weight of the j-th oil cylinder, that is, the weight of the oil cylinder with the maximum absolute value of the real-time displacement deviation;

[0037] Among them, the expression for calculating the weights of the remaining oil cylinders is:

[0038]

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

[0040]

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

[0042] Furthermore, the expression of 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] In a second aspect, the present invention provides a synchronization control system based on the displacement of the cylinder, and the technical solution of the system is as follows:

[0046] An acquisition module, configured to acquire the independent displacement signal and the independent working pressure signal corresponding to each cylinder in the cylinder parallel system; wherein, the cylinder parallel system is driven by a hydraulic system, and the hydraulic system provides hydraulic oil for each cylinder through an independent proportional flow valve;

[0047] A calculation module, configured to generate a global target displacement value based on a preset displacement-time continuous function, and calculate the real-time displacement deviation value corresponding to the independent displacement signal of each cylinder according to the global target displacement value;

[0048] A generation module, configured to generate a dynamic compensation coefficient corresponding to each cylinder according to the real-time displacement deviation value corresponding to each cylinder, and respectively generate a dynamic compensation coefficient corresponding to each cylinder 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 cylinder, and the load change rate is calculated by the pressure change gradient of the independent working pressure signal of the corresponding cylinder within a unit time;

[0049] The control module is used to independently adjust the opening command value of the proportional flow valve corresponding to each oil cylinder according to the dynamic compensation coefficient of each oil cylinder, where the weight distribution rule is: the oil cylinder with the largest absolute value of the real-time displacement deviation is given priority to obtain the largest compensation flow, and the remaining oil cylinders are allocated the remaining flow according to the deviation ratio;

[0050] The loop module is used to loop and 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 the preset deviation threshold;

[0051] Among them, the total pressure parameter of the hydraulic system is the preset upper limit value of the system oil supply pressure, and the 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 the displacement synchronization control.

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

[0053] The system of the present invention can effectively reduce the influence of load changes and complex working conditions on the synchronization accuracy of the oil cylinders, more accurately achieve the synchronization control of the oil cylinders, ensure high-precision operation, and at the same time reasonably utilize the oil supply capacity of the hydraulic system, and trigger the pressure protection with a lower priority only when the total demand flow exceeds the oil supply capacity, improve the reliability and stability of the operation of the hydraulic system, reduce the system energy consumption, and meet the requirements of high-precision operation equipment.

[0054] The above description is only an overview of the technical solution of the present invention. In order to be able to understand the technical means of the present invention more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of the present invention more obvious and understandable, the specific embodiments of the present invention are given below. Description of the Drawings

[0055] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0056] The drawings are only used to show the embodiments and are not considered as a limitation of the present invention. And throughout the drawings, the same reference numerals are used to represent the same components. In the drawings:

[0057] Figure 1 is a schematic flow chart of an embodiment of a synchronous control method based on the displacement of the oil cylinder of the present invention;

[0058] Figure 2Schematic structural diagram of an embodiment of a synchronous control system based on the displacement of an oil cylinder according to the present invention. Detailed implementation manners

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

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

[0061] S1. Obtain the independent displacement signal and independent working pressure signal 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 an independent proportional flow valve;

[0062] S2. Generate a global target displacement value based on a pre-set displacement-time continuous function, and calculate the real-time displacement deviation value corresponding to the independent displacement signal of each oil cylinder according to the global target displacement value;

[0063] S3. According to the real-time displacement deviation value corresponding to each oil cylinder, respectively generate a dynamic compensation coefficient corresponding to each oil cylinder 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 oil cylinder, and the load change rate is calculated through the pressure change gradient of the independent working pressure signal of the corresponding oil cylinder within a unit time;

[0064] S4. According to the dynamic compensation coefficient of each oil cylinder, independently adjust the opening command value of the proportional flow valve corresponding to each oil cylinder according to the weight distribution rule, and the weight distribution rule is: the oil cylinder with the largest absolute value of the real-time displacement deviation preferentially obtains the largest compensation flow, and the remaining oil cylinders distribute the remaining flow according to the deviation ratio;

[0065] S5. Loop through steps S1 to S4 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 preset deviation threshold;

[0066] Wherein, the total pressure parameter of the hydraulic system is the preset upper limit value of the system oil supply pressure, and the pressure protection is triggered only when the total required 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 the displacement synchronous control.

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

[0068] Preset the displacement-time continuous function s(t) according to the operation requirements, and input the current time t k into the displacement-time continuous function s(t) to generate the global target displacement value s k at the current time t tar get (t k ) = s(t k ).

[0069] In an alternative manner, the step of calculating the real-time displacement deviation value corresponding to the independent displacement signal of each oil cylinder according to the global target displacement value further includes:

[0070] Obtain the actual displacement value s k corresponding to the independent displacement signal of the i-th oil cylinder at the current time t i (t k ), and combine it with the global target displacement value s k at the current time t tar get (t k ) to calculate the real-time displacement deviation value e i (t k ) of the i-th oil cylinder until the real-time displacement deviation value corresponding to each oil cylinder is calculated; wherein, 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 an alternative manner, the step of generating the 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 the adaptive proportional-integral algorithm further includes:

[0072] Obtain the working pressure p k of the i-th oil cylinder corresponding to the independent working pressure signal at the current time t i (t k ), and calculate the load change rate γ k of the i-th oil cylinder at the current time t i (t k ), and its expression is:

[0073]

[0074] where 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 cycle at the current moment t k .

[0075] According to the load change rate γ k (t i ) of the i-th oil cylinder at the current moment t k , adjust the integral time constant T i (t k ) in the adaptive proportional-integral algorithm, and its expression is:

[0076]

[0077] In the formula, T base represents the reference integral time constant, which is preset according to the system stability requirement; β represents the load change rate adjustment coefficient, which is used to control the sensitivity of the integral time constant to the load change;

[0078] According to the real-time displacement deviation value e i (t k ) corresponding to the i-th oil cylinder and the adjusted integral time constant T i (t k ), calculate and generate the dynamic compensation coefficient K i (t k ) corresponding to the i-th oil cylinder through the adaptive proportional-integral algorithm, and its expression is:

[0079]

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

[0081] In an optional manner, the step of independently adjusting the opening command value of the proportional flow valve corresponding to each oil cylinder according to the dynamic compensation coefficient of each oil cylinder further includes:

[0082] Obtain the absolute value of the real-time displacement deviation corresponding to each oil cylinder, traverse the absolute values of the real-time displacement deviations of all oil cylinders, and determine the index j of the oil cylinder with the largest absolute value of the real-time displacement deviation, and 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 oil cylinder, and N represents the number of oil cylinders in the oil cylinder parallel system;

[0085] Calculate the sum of the absolute values of the real-time displacement deviations of all oil cylinders, and calculate the weight of the oil cylinder with the largest absolute value of the real-time displacement deviation and the weight distribution of the remaining oil cylinders;

[0086] Among them, the expression for calculating the weight of the oil cylinder with the largest absolute value of the real-time displacement deviation is:

[0087]

[0088] In the formula, w j represents the weight of the j-th oil cylinder, that is, the weight of the oil cylinder with the largest absolute value of the real-time displacement deviation;

[0089] Among them, the expression for calculating the weight of the remaining oil cylinders is:

[0090]

[0091] According to the dynamic compensation coefficient and the weight of each oil cylinder, calculate the opening command value of the proportional flow valve corresponding to each oil cylinder respectively, and its expression is:

[0092]

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

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

[0095] In an alternative manner, the expression of 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 influence of load changes and complex working conditions on the cylinder synchronization accuracy, more accurately achieve cylinder synchronization control, ensure high-precision operation, and at the same time reasonably utilize the oil supply capacity of the hydraulic system. Only when the total required flow exceeds the oil supply capacity, the pressure protection with a lower priority is triggered, improving the reliability and stability of the hydraulic system operation, reducing the system energy consumption, and meeting the requirements of high-precision operation equipment.

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

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

[0101] A calculation module 220, configured to generate a global target displacement value based on a preset displacement-time continuous function, and calculate real-time displacement deviation values corresponding to the independent displacement signals of each cylinder according to the global target displacement value;

[0102] A generation module 230, configured to generate dynamic compensation coefficients corresponding to each cylinder respectively according to the real-time displacement deviation values corresponding to each cylinder, and by using 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 cylinder, and the load change rate is calculated through the pressure change gradient of the independent working pressure signal of the corresponding cylinder within a unit time;

[0103] A control module 240, configured to independently adjust the opening command values of the proportional flow valves corresponding to each cylinder according to the dynamic compensation coefficients of each cylinder, and the weight distribution rule is: the cylinder with the largest absolute value of the real-time displacement deviation is given priority to obtain the largest compensation flow, and the remaining cylinders distribute the remaining flow according to the deviation ratio;

[0104] A loop module 250, configured to loop and 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 a preset deviation threshold;

[0105] Among them, the total pressure parameter of the hydraulic system is the preset upper limit value of the system oil supply pressure, and the pressure protection is triggered only when the total required flow rate 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 influence of load changes and complex working conditions on the cylinder synchronization accuracy, more accurately achieve cylinder synchronization control, ensure high-precision operation, and at the same time rationally utilize the oil supply capacity of the hydraulic system. The pressure protection with a lower priority is triggered only when the total required flow rate exceeds the oil supply capacity, improving the reliability and stability of the hydraulic system operation, reducing system energy consumption, and meeting the requirements of high-precision operation equipment.

[0107] In addition, when the system provided in the above embodiment realizes its functions, only the division of the above-mentioned functional modules is used for illustration. In actual applications, the above functions can be allocated to different functional modules according to needs, 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 provided in the above embodiment and the method embodiment belong to the same concept, and the specific implementation process is detailed in the method embodiment and will not be repeated here.

[0108] The above description is only a preferred embodiment of the present invention and an explanation of the applied technical principles. Those skilled in the art should understand that the scope of disclosure involved in the present invention is not limited to the technical solutions formed by the specific combination of the above technical features, but also covers other technical solutions formed by any combination of the above technical features or their equivalent features without departing from the above disclosure concept. For example, the technical solutions formed by mutually replacing the above features with the (but not limited to) technical features with similar functions disclosed in the present invention.

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

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

Claims

1. A synchronous control method based on the displacement of an oil cylinder, characterized in that, The method includes: S1. Obtain the independent displacement signal and independent working pressure signal 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 an independent proportional flow valve; S2. Generate a global target displacement value based on a preset displacement-time continuous function, and calculate the real-time displacement deviation value corresponding to the independent displacement signal of each oil cylinder according to the global target displacement value; S3. According to the real-time displacement deviation value corresponding to each oil cylinder, respectively generate a dynamic compensation coefficient for each oil cylinder 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 oil cylinder, and the load change rate is calculated through the pressure change gradient of the independent working pressure signal of the corresponding oil cylinder within a unit time; S4. According to the dynamic compensation coefficient of each oil cylinder, independently adjust the opening command value of the proportional flow valve corresponding to each oil cylinder according to the weight distribution rule, where the weight distribution rule is: the oil cylinder with the largest absolute value of the real-time displacement deviation obtains the largest compensation flow first, and the remaining oil cylinders distribute the remaining flow according to the deviation ratio; S5. Loop and execute steps S1 to S4 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 preset deviation threshold; Wherein, the total pressure parameter of the hydraulic system is the preset upper limit value of the system oil supply pressure, and pressure protection is triggered only when the total required 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 the displacement synchronization control.

2. The synchronous control method based on the displacement of the oil cylinder according to claim 1, wherein The step of generating the global target displacement value based on a preset displacement-time continuous function further includes: Preset the displacement-time continuous function s(t) according to the operation requirements, and input the current time t k into the displacement-time continuous function s(t) to generate the global target displacement value s k at the current time t target (t k ) = s(t k ).

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

4. The synchronous control method based on the displacement of the oil cylinder according to claim 3, characterized in that The step of generating the 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 through an adaptive proportional-integral algorithm further includes: Obtain the working pressure p of the i-th oil cylinder corresponding to the independent working pressure signal at the current moment t k and calculate the load change rate γ of the i-th oil cylinder at the current moment t i (t k ), and its expression is: k The load change rate γ i (t k ) where 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 moment t k ; According to the load change rate γ k of the i-th oil cylinder at the current moment t i (t k ), adjust the integral time constant T i (t k ) in the adaptive proportional-integral algorithm. The expression is as follows: where T base represents the reference integral time constant, which is preset according to the system stability requirements; β represents the load change rate adjustment coefficient, which is used to control the sensitivity of the integral time constant to load changes; According to the real-time displacement deviation value e corresponding to the i-th oil cylinder i (t k ) and the adjusted integral time constant T i (t k ), the dynamic compensation coefficient K corresponding to the i-th oil cylinder is calculated and generated through the adaptive proportional-integral algorithm i (t k ), and its expression is: Wherein, K p represents a preset proportional gain coefficient; K I (t k ) represents a dynamic integral gain coefficient, which is determined by the adjusted integral time constant T i (t k ), m represents the index variable of the time step, m ∈ [0, k].

5. The synchronous control method based on the displacement of the oil cylinder according to claim 4, wherein The step of independently adjusting the opening command value of the proportional flow valve corresponding to each oil cylinder according to the weight distribution rule according to the dynamic compensation coefficient of each oil cylinder further includes: Obtain the absolute value of the real-time displacement deviation corresponding to each oil cylinder, traverse the absolute values of the real-time displacement deviations of all oil cylinders, and determine the cylinder index j of the largest absolute value of the real-time displacement deviation, and its expression is: where, |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 parallel system; Calculate the sum of the absolute values of the real-time displacement deviations of all oil cylinders, and calculate the weight of the oil cylinder with the largest absolute value of the real-time displacement deviation and the weight distribution of the remaining oil cylinders; Wherein, the expression for calculating the weight of the oil cylinder with the largest absolute value of the real-time displacement deviation is: In the formula, w j represents the weight of the j-th oil cylinder, that is, the weight of the oil cylinder with the largest absolute value of the real-time displacement deviation; Wherein, the expression for calculating the weight of the remaining oil cylinders is: According to the dynamic compensation coefficient and cylinder weight of each oil cylinder, respectively calculate the opening command value of the proportional flow valve corresponding to each oil cylinder, and its expression is: where, U i (t k ) represents the opening command value of the proportional flow valve corresponding to the i-th oil cylinder, and U max represents the maximum opening command value of the proportional flow valve.

6. The synchronous control method based on the displacement of the oil cylinder according to any one of claims 2 to 5, characterized in that, 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 velocity, acceleration and jerk boundary conditions corresponding to the operation requirements.

7. A synchronous control system based on the displacement of an oil cylinder, characterized in that, The system includes: An acquisition module, configured to acquire an independent displacement signal and an independent working pressure signal corresponding to each oil cylinder in an 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 an independent proportional flow valve; A calculation module, configured to generate a global target displacement value based on a preset 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, 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 by using 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 oil cylinder, and the load change rate is calculated from the pressure change gradient of the independent working pressure signal of the corresponding oil cylinder within a unit time; A control module, configured to independently adjust the opening command value of the proportional flow valve corresponding to each oil cylinder according to the dynamic compensation coefficient of each oil cylinder according to a weight distribution rule, wherein the weight distribution rule is: the oil cylinder with the largest absolute value of the real-time displacement deviation is given priority to obtain the largest compensation flow, and the remaining oil cylinders distribute the remaining flow according to the deviation ratio; A loop module, configured to loop and 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 preset deviation threshold; Wherein, the total pressure parameter of the hydraulic system is a preset upper limit value of the system oil supply pressure, and pressure protection is triggered only when the total required 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.

8. The synchronous control system based on the displacement of the oil cylinder according to claim 7, wherein The calculation module is specifically configured to: Preset the displacement-time continuous function s(t) according to the operation requirements, and input the current moment t k into the displacement-time continuous function s(t) to generate the global target displacement value s k at the current moment 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 in that, The calculation module is specifically configured to: Obtain the actual displacement value s corresponding to the independent displacement signal of the i-th oil cylinder at the current moment t k (t i )), and combine the global target displacement value s of the current moment t k (t k ) to calculate the real-time displacement deviation value e of the i-th oil cylinder target (t k ), until the real-time displacement deviation values corresponding to each oil cylinder are calculated; where the expression for calculating the real-time displacement deviation value is: e i (t k ) = s 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 in that, The generation module is specifically configured to: Obtain the working pressure p of the i-th oil cylinder corresponding to the independent working pressure signal at the current moment t k , and calculate the load change rate γ i (t k ) of the i-th oil cylinder at the current moment t k . Its expression is: i (t k ) Where 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 moment t k ; According to the load change rate γ k of the i-th oil cylinder at the current moment t i (t k ), adjust the integral time constant T i (t k ) in the adaptive proportional-integral algorithm, and its expression is: where T base represents the reference integral time constant, which is preset according to the system stability requirements; β represents the load change rate adjustment coefficient, which is used to control the sensitivity of the integral time constant to load changes; According to the real-time displacement deviation value e corresponding to the i-th oil cylinder i (t k ) and the adjusted integral time constant T i (t k ), the dynamic compensation coefficient K corresponding to the i-th oil cylinder is calculated and generated through the adaptive proportional-integral algorithm i (t k ), and its expression is: where K p represents a preset proportional gain coefficient; K I (t k ) represents a dynamic integral gain coefficient, which is determined by the adjusted integral time constant T i (t k ); m represents the index variable of the time step, and m ∈ [0, k].

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