A Fuzzy Sliding Mode Control Method for Electro-Hydraulic Servo System Integrating Class Potential Function

Abstract

The invention discloses a fuzzy sliding mode control method for an electro-hydraulic servo system integrating a potential function, which includes: calculating a trajectory tracking error based on a desired motion trajectory and an actual motion trajectory; establishing a state model of a nonlinear electro-hydraulic servo system according to an actual working state and the trajectory tracking error; constructing a sliding mode surface for obtaining the integrated potential function to improve transient and steady-state tracking performance; designing a fuzzy sliding mode control method based on an adaptive strategy to obtain an equivalent control signal and real-time estimate unknown parameters of the system; designing a fuzzy sliding mode control method based on a fuzzy strategy to obtain a switching control signal to reduce the system chattering problem; and outputting an actual control signal to the electro-hydraulic servo system based on the equivalent control signal and the switching control signal. The control method of the invention can quickly and smoothly track a reference trajectory, has strong anti-interference ability, and effectively improves the trajectory tracking accuracy and robustness of the electro-hydraulic servo system.

Description

Technical Field

[0001] The present invention belongs to the technical field of electro-hydraulic servo system control, and particularly relates to a fuzzy sliding mode control method for an electro-hydraulic servo system integrating a potential function-like function. Background Art

[0002] The electro-hydraulic servo system has a simple structure, is easy to operate and is suitable for high-power applications, and has been widely used in various construction equipment, construction machinery and numerical control equipment. However, the electro-hydraulic servo system is nonlinear and has problems such as parameter perturbation and external interference, which are mainly manifested as parameter uncertainties and modeling errors caused by factors such as friction and load, and non-parameter uncertainties caused by factors such as external interference, seriously restricting the trajectory tracking accuracy and the overall performance of the machine.

[0003] The parameters of the traditional Proportional Integral Derivative (PID) control are fixed once set and cannot be adjusted in a timely manner according to the working conditions, and cannot meet the high-precision requirements of the electro-hydraulic servo system, and the parameter setting is complicated. Some advanced controllers have also been proposed, such as sliding mode control, neural network, deep learning, backstepping control, etc. Among these advanced controllers, sliding mode control, as a control method suitable for nonlinear systems, has received extensive attention, and other advanced controllers have disadvantages such as complex design and heavy computational burden.

[0004] The chattering phenomenon limits the application of sliding mode control in the electro-hydraulic servo system. In addition, when the system model parameters are unknown, the optimal equivalent control law in sliding mode control cannot be obtained. To ensure that the control method can reach the switching surface, it is usually necessary to know the uncertainty boundary of the system, which is also difficult to achieve in actual engineering. Summary of the Invention

[0005] The purpose of the present invention is to propose a fuzzy sliding mode control method for an electro-hydraulic servo system integrating a potential function-like function in view of the above problems. A nonlinear integral sliding surface is designed by introducing a potential function-like function to improve the transient and steady-state tracking performance; an adaptive strategy is adopted to design an equivalent control law to realize real-time estimation of unknown system parameters; a fuzzy strategy is adopted to reduce the system chattering problem and ensure that the switching control gain is greater than the upper bound of the disturbance within a finite time. This control method can quickly and smoothly track the reference trajectory, has strong anti-interference ability, and effectively improves the trajectory tracking accuracy and robustness of the electro-hydraulic servo system.

[0006] To achieve the above purpose, the present invention adopts the following technical solutions:

[0007] In the first aspect, a fuzzy sliding mode control method for an electro-hydraulic servo system integrating a potential function-like function is provided, including:

[0008] Step S1: Set the desired motion trajectory r, obtain the actual motion trajectory y of the electro-hydraulic servo system, and calculate the trajectory tracking errors e, e1, e2, and e3 based on the desired motion trajectory r and the actual motion trajectory y;

[0009] Step S2: Construct and obtain the state model of the nonlinear electro-hydraulic servo system according to the actual working state and the trajectory tracking error;

[0010] Step S3: Construct and obtain the sliding mode surface of the integrated potential function based on the trajectory tracking errors e, e1, e2, and e3;

[0011] Step S4: Based on the sliding mode surface of the integrated potential function and the state model of the nonlinear electro-hydraulic servo system, obtain the equivalent control signal u using an adaptive strategy eq ;

[0012] Step S5: Based on the sliding mode surface of the integrated potential function, obtain the switching control signal u using a fuzzy strategy n ;

[0013] Step S6: Based on the equivalent control signal u eq and the switching control signal u n , obtain the final actual control signal u and output the actual control signal to the electro-hydraulic servo system.

[0014] In some embodiments, step S1 includes:

[0015] S1.1: Set the desired motion trajectory through a fifth-degree polynomial, interpolate and segment the desired motion trajectory. The desired motion trajectory r is:

[0016]

[0017] where x0 is the starting point of the desired motion trajectory, x1 is the ending point of the desired motion trajectory, t b is the time elapsed from x0 to x1, and t is time;

[0018] S1.2: Obtain the actual motion trajectory y of the electro-hydraulic servo system;

[0019] S1.3: Calculate the trajectory tracking errors e, e1, e2, and e3 based on the desired motion trajectory r and the actual motion trajectory y:

[0020]

[0021] In some embodiments, in step S2, the state model of the nonlinear electro-hydraulic servo system includes:

[0022]

[0023] Among them, u is the control input signal, e, e1, e2, and e3 are the trajectory tracking errors, and a0, a1, a2, b, and f are coefficients related to the electro-hydraulic servo system, which are determined according to the actual working state. The expression is:

[0024]

[0025] Among them, n = A2 / A1, where A1 and A2 are the effective areas of the rodless chamber and the rod chamber of the hydraulic cylinder, and β e is the effective bulk modulus, K t is the total flow pressure coefficient, K is the equivalent spring stiffness of the load, V is the total chamber volume, m is the equivalent mass of the moving parts, and B c is the viscous damping coefficient, K a 、K b is the amplification coefficient, K q is the flow gain coefficient, and F L is the equivalent load force.

[0026] 4. The method according to claim 1, wherein in step S3, constructing a sliding surface s for obtaining the integrated potential function includes:

[0027]

[0028] Among them, c1, c2, and β are the sliding surface parameters; σ is the adjustment coefficient; G is the introduced potential function. When the error e is large, the first derivative g of G will tend to saturate, reducing the integral effect and avoiding the accumulation of initial errors; when the error e is very small, the integral effect is introduced to reduce the steady-state error; it avoids the problems of deteriorated transient performance, integral saturation effect, and system instability caused by the large initial error in sliding mode control.

[0029] In some embodiments, step S4 includes:

[0030] The equivalent control law u eq ' is designed as:

[0031]

[0032] Among them, e1, e2, and e3 are the trajectory tracking errors, a0, a1, a2, b, and f are the coefficients related to the electro-hydraulic servo system, c1, c2, and β are the sliding surface parameters, and g is the first derivative of the introduced potential function G; since a0, a1, a2, b, and f are uncertain, the equivalent control law u eq ' cannot be accurately obtained,

[0033] An adaptive strategy is adopted to obtain the equivalent control signal u eq :

[0034]

[0035] is the parameter value of adaptive estimation, which is obtained by using an adaptive strategy based on the sliding mode surface of the integrated class potential function and the state model of the nonlinear electro-hydraulic servo system, as shown in the following formula:

[0036]

[0037] where γ1, γ2, γ3, γ4, γ5 are adaptive laws.

[0038] In some embodiments, step S5 includes: switching the control signal u n The expression is:

[0039] u n = k sgn(s)

[0040] where sgn is the sign function; k is the gain coefficient of the switching control signal, and the value of k is adjusted based on the sliding mode surface of the integrated class potential function using fuzzy logic control rules to ensure good performance of the system.

[0041] In some embodiments, based on the sliding mode surface of the integrated class potential function, adjusting the value of k using fuzzy logic control rules includes:

[0042] S5.1. Define the input-output structure of the fuzzy controller: Design a two-dimensional fuzzy controller with two inputs and one output, using the sliding mode surface s and its rate of change as inputs and the gain coefficient k of the switching control signal as the output;

[0043] S5.2. Define the fuzzy sets of the fuzzy controller: The inputs are defined as 5 fuzzy sets: "Negative Big" (NB), "Negative Small" (NS), "Zero" (ZR), "Positive Small" (PS), and "Positive Big" (PB), and the output is defined as seven fuzzy sets: "Negative Big" (NB), "Negative Medium" (NM), "Negative Small" (NS), "Zero" (ZR), "Positive Small" (PS), "Positive Medium" (PM), "Positive Big" (PB);

[0044] S5.3. Define the fuzzy universe of discourse of the fuzzy controller as the following formula:

[0045]

[0046] S5.4. Solve the fuzzy using the centroid method to obtain the gain coefficient k of the switching control signal.

[0047] In some embodiments, in step S6, the actual control signal u is:

[0048] u = u eq + u n .

[0049] In a second aspect, the present invention provides a fuzzy sliding mode control device for an electro-hydraulic servo system integrating a potential function-like function, comprising a processor and a storage medium;

[0050] The storage medium is used for storing instructions;

[0051] The processor is configured to operate according to the instructions to execute the steps of the method according to the first aspect.

[0052] In a third aspect, the present invention provides a storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the method according to the first aspect are implemented.

[0053] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0054] The present invention provides a fuzzy sliding mode control method for an electro-hydraulic servo system integrating a potential function-like function. This control method mainly consists of three parts: a non-linear integral term sliding mode surface integrating a potential function-like function, an adaptive strategy, and a fuzzy switching strategy. The non-linear integral term sliding mode surface integrating a potential function-like function is used to ensure transient and steady-state trajectory tracking performance; the adaptive strategy is used to approximate the equivalent control law to avoid the defects of known parameter uncertainties and bounded external disturbances; a fuzzy switching strategy is proposed to adjust the switching control gain to reduce the chattering phenomenon. Compared with traditional sliding mode control and PID control, this control method can track the reference trajectory quickly and smoothly, has strong anti-interference ability, effectively improves the trajectory tracking accuracy and robustness of the electro-hydraulic servo system, and lays a foundation for functions such as intelligent control, theoretical analysis, and intelligent construction. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 is a schematic diagram of the electro-hydraulic servo system of an excavator according to an embodiment of the present invention.

[0056] Figure 2 is a control block diagram of the fuzzy sliding mode control method according to an embodiment of the present invention.

[0057] Figure 3 is the potential function-like function introduced according to an embodiment of the present invention.

[0058] Figure 4 is the fuzzy domain of the sliding mode surface s according to an embodiment of the present invention.

[0059] Figure 5 is the fuzzy domain of the change rate of the sliding mode surface s according to an embodiment of the present invention.

[0060] Figure 6 is the fuzzy domain of the switching control signal k according to an embodiment of the present invention.

[0061] Figure 7 is the simulation result of the traditional sliding mode control and the control method of the present invention under a step reference trajectory according to an embodiment of the present invention. Detailed implementation manners

[0062] The present invention will be further described below with reference to the accompanying drawings and embodiments. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0063] In the description of the present invention, the meaning of several is more than one, the meaning of a plurality is more than two, greater than, less than, exceeding, etc. are understood as not including the present number, above, below, within, etc. are understood as including the present number. If the first and second are described only for the purpose of distinguishing technical features, they cannot be understood as indicating or implying relative importance or implicitly indicating the quantity of the indicated technical features or implicitly indicating the sequence relationship of the indicated technical features.

[0064] In the description of the present invention, the description with reference to terms such as "one embodiment", "some embodiments", "schematic embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0065] Embodiment 1

[0066] A fuzzy sliding mode control method for an electro-hydraulic servo system integrating a potential function includes:

[0067] Step S1: Set the desired motion trajectory r, obtain the actual motion trajectory y of the electro-hydraulic servo system, and calculate the trajectory tracking errors e, e1, e2, and e3 based on the desired motion trajectory r and the actual motion trajectory y;

[0068] Step S2: Construct and obtain a state model of the nonlinear electro-hydraulic servo system according to the actual working state and the trajectory tracking error;

[0069] Step S3: Construct and obtain a sliding mode surface integrating a potential function based on the trajectory tracking errors e, e1, e2, and e3;

[0070] Step S4: Based on the sliding mode surface integrating a potential function and the state model of the nonlinear electro-hydraulic servo system, adopt an adaptive strategy to obtain an equivalent control signal u eq ;

[0071] Step S5: Based on the sliding mode surface integrating a potential function, adopt a fuzzy strategy to obtain a switching control signal u n ;

[0072] Step S6: Based on the equivalent control signal ueq and the switching control signal u n , the final actual control signal u is obtained, and the actual control signal is output to the electro-hydraulic servo system.

[0073] Specific embodiment: In this embodiment, the verification implementation of the fuzzy sliding mode control method for the electro-hydraulic servo system is carried out on a typical excavator. The experimental platform is as Figure 1 shown. The electro-hydraulic servo system of the excavator consists of an engine, a hydraulic pump, an electro-hydraulic servo valve, a hydraulic cylinder, a controller, and a sensor. For the most commonly used working device, it includes a boom, a stick, and a bucket triple electro-hydraulic servo system. The displacement sensor and the data acquisition card collect the displacement of the hydraulic cylinder, and then input the displacement signal into the controller. The fuzzy sliding mode control method in the controller calculates the control signal according to the desired displacement and the actual displacement. The control signal drives the electro-hydraulic servo valve to move, resulting in a flow change, thereby controlling the displacement of the hydraulic cylinder. A fuzzy sliding mode control method for an electro-hydraulic servo system integrating a potential function, the control block diagram is as Figure 2 shown, and specifically includes the following steps:

[0074] S1. Calculate the error between the desired motion trajectory and the actual motion trajectory. Set the desired motion trajectory, obtain the actual motion trajectory, and calculate the error between the desired motion trajectory and the actual motion trajectory, including the following steps:

[0075] S1.1. Set the desired motion trajectory through a fifth-degree polynomial, interpolate and segment the desired motion trajectory. Taking the desired motion trajectory as a step signal as an example, that is, y = 1m, the desired motion trajectory r is:

[0076]

[0077] where x0 is the starting point of the desired motion trajectory x0 = (0, 1), x1 is the ending point of the desired motion trajectory x1 = (10, 1), t b is the time experienced from x0 to x1, t b = 10s, and t is the time.

[0078] S1.2. Obtain the actual motion trajectory signal y of the bucket-linked electro-hydraulic servo system of the excavator. The goal of trajectory control is to design a tracking control method that satisfies the following formula when the system has unmodeled dynamics and parameter uncertainties:

[0079]

[0080] S2. Establish a nonlinear electro-hydraulic servo system state model based on the error according to the actual working state. Analyze the working principle of the typical excavator electro-hydraulic servo system, and establish a bucket-linked nonlinear electro-hydraulic servo system state model according to the actual working state and the trajectory tracking error, as shown in the following formula:

[0081]

[0082] Among them, u is the control input signal, and e, e1, e2, and e3 are the trajectory tracking errors, and the expressions are:

[0083]

[0084] a0, a1, a2, b, and f are coefficients related to the electro-hydraulic servo system, which are determined according to the actual working state, and the expressions are:

[0085]

[0086] Among them, n = A2 / A1, A1 and A2 are the effective areas of the rodless chamber and the rod chamber of the hydraulic cylinder, and β e is the effective bulk modulus, K t is the total flow pressure coefficient, K is the equivalent spring stiffness of the load, V is the total volume of the chamber, m is the equivalent mass of the moving parts, and B c is the viscous damping coefficient, K a 、K b is the amplification coefficient, K q is the flow gain coefficient, F L is the equivalent load force.

[0087] S3. Design the sliding mode surface of the integrated potential function as shown in the following formula:

[0088]

[0089] Among them, c1, c2, and β are the sliding mode surface parameters, c1 = 21222, c2 = 205, β = 78000; σ is the adjustment coefficient, σ = 1; G is the introduced potential function, as Figure 3 shown. When the error e is large, g will tend to saturate, reducing the integral effect and avoiding the accumulation of initial errors. When the error e is very small, the integral effect is introduced to reduce the steady-state error. It avoids the problems of deteriorated transient performance, integral saturation effect, and system instability caused by the large initial error in sliding mode control.

[0090] S4. Design the equivalent control signal of the fuzzy sliding mode control method based on the adaptive strategy. The equivalent control law u eq ' is designed as:

[0091]

[0092] Parameters of the system such as the flow coefficient, leakage coefficient, and viscous damping coefficient have obvious uncertainties and change slowly with the working state and temperature. In addition, the equivalent load force is also time-varying. Therefore, the system parameters a0, a1, a2, b, and f are uncertain, and the equivalent control law u eq ' cannot be accurately obtained, and an adaptive strategy is used to find the equivalent control law u eq :

[0093]

[0094] Among them, are the parameter values estimated adaptively, and are estimated based on the sliding mode surface of the integrated potential function and the state model of the nonlinear electro-hydraulic servo system using an adaptive strategy, as shown in the following formula:

[0095]

[0096] Among them, γ1, γ2, γ3, γ4, and γ5 are adaptive laws, and in this embodiment, γ1 = γ2 = γ3 = γ4 = γ5 = 50.

[0097] S5. Design the switching control signal of the fuzzy sliding mode control method based on the fuzzy strategy. The specific method is to adjust the k value using fuzzy logic control rules to ensure that the system has good performance. The above-mentioned k value is the gain coefficient of the switching control signal, and the expression of the switching control signal is:

[0098] u n = k sgn(s) (10)

[0099] Among them, sgn is the sign function.

[0100] The specific steps of S5 are:

[0101] S5.1. Define the input-output structure of the fuzzy controller. Design a two-dimensional fuzzy controller with two inputs and one output, using the sliding mode surface s and its rate of change as inputs and k in the switching control signal as the output. The fuzzy universes of the sliding mode surface s, its rate of change, and the switching control signal k are respectively as Figure 4 、 5 、6 show.

[0102] S5.2. Define the fuzzy sets of the fuzzy controller. The input is defined as 5 fuzzy sets: "Negative Big" (NB), "Negative Small" (NS), "Zero" (ZR), "Positive Small" (PS), and "Positive Big" (PB), and the output is defined as seven fuzzy sets: "Negative Big" (NB), "Negative Medium" (NM), "Negative Small" (NS), "Zero" (ZR), "Positive Small" (PS), "Positive Medium" (PM), "Positive Big" (PB).

[0103] S5.3. Define the fuzzy domain of the fuzzy controller as follows:

[0104]

[0105] S5.4. Use the centroid method to solve the fuzzy problem. Take the centroid of the area enclosed by the membership function curve and the abscissa as the output value, and calculate the gain coefficient k of the switching control signal.

[0106] Furthermore, in step S6, output the actual control signal to the electro-hydraulic servo system. The final actual control signal u is:

[0107] u = u eq + u n (12)

[0108] In this embodiment, in step S6, finally connect the actual control signal u to the electro-hydraulic servo system of the bucket of the excavator. The displacement sensor continuously obtains the actual displacement to achieve precise position control of the electro-hydraulic servo system.

[0109] The final simulation results of the embodiment are as Figure 7 shown. In the embodiment, the traditional sliding mode control method is used for comparison with the control method of the present invention. At t = 5s, a disturbance is added to the reference trajectory to verify the superiority of the control method of the present invention. The rise time and settling time of the traditional sliding mode control method are 0.44s and 1.08s respectively, while those of the control method of the present invention are only 0.37s and 0.71s. In addition, under the influence of external disturbances, the maximum overshoot of the control method of the present invention is only 0.97%, while the overshoot of the traditional sliding mode control method is 6.53%. Therefore, the control method of the present invention has strong anti-interference ability, fast dynamic response, small overshoot, and better control effect than the traditional sliding mode control method, and can effectively track the desired motion trajectory.

[0110] The present invention provides a fuzzy sliding mode control method for an electro-hydraulic servo system integrating a potential function-like function. There are many methods and ways to specifically implement this technical solution. The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention. Each component not clearly defined in this embodiment can be implemented by existing technologies.

[0111] Embodiment 2

[0112] Second, this embodiment provides a fuzzy sliding mode control device for an electro-hydraulic servo system integrating a potential function-like function, including a processor and a storage medium;

[0113] The storage medium is used to store instructions;

[0114] The processor is used to operate according to the instructions to execute the steps of the method according to Embodiment 1.

[0115] Embodiment 3

[0116] In a third aspect, this embodiment provides a storage medium, on which a computer program is stored, and when the computer program is executed by a processor, the steps of the method according to Embodiment 1 are implemented.

[0117] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0118] The present application is described with reference to the flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram can be implemented by computer program instructions, and the combination of the flows and / or blocks in the flowchart and / or block diagram can also be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate a device for implementing the specified functions in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0119] These computer program instructions can also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate a manufactured article including an instruction device, and the instruction device implements the specified functions in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0120] These computer program instructions can also be loaded onto a computer or other programmable data processing device, so that a series of operation steps are executed on the computer or other programmable device to generate a computer-implemented process, and thus the instructions executed on the computer or other programmable device provide steps for implementing the specified functions in one Figure 1 one flow or multiple flows and / or blocks Figure 1 one block or multiple blocks.

[0121] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A fuzzy sliding mode control method for an electro-hydraulic servo system integrating a potential function, characterized in that, Including: Step S1: Set the desired motion trajectory r, obtain the actual motion trajectory y of the electro-hydraulic servo system, and calculate the trajectory tracking errors e, e1, e2, and e3 based on the desired motion trajectory r and the actual motion trajectory y. Step S2: Construct and obtain the state model of the nonlinear electro-hydraulic servo system according to the actual working state and the trajectory tracking error. Step S3: Based on the trajectory tracking errors e, e1, e2, and e3, construct and obtain the sliding mode surface s of the integrated-like potential function. Including: Wherein, c1, c2, and β are sliding mode surface parameters; σ is an adjustment coefficient; G is the introduced-like potential function. When the error e is large, the first derivative g of G will tend to saturation, reducing the integral effect and avoiding the accumulation of initial errors. When the error e is very small, the integral effect is introduced to reduce the steady-state error. It avoids the problems of deteriorated transient performance, integral saturation effect, and system instability caused by the large initial error in sliding mode control. Step S4: Based on the sliding mode surface of the integrated class potential function and the state model of the nonlinear electro-hydraulic servo system, an equivalent control signal u is obtained by using an adaptive strategy eq , including: Equivalent control law u eq is designed as: Among them, e1, e2, and e3 are trajectory tracking errors, a0, a1, a2, b, and f are coefficients related to the electro-hydraulic servo system, c1, c2, and β are sliding mode surface parameters, and g is the first derivative of the introduced potential-like function G; since a0, a1, a2, b, and f are uncertain, the equivalent control law u eq ' An adaptive strategy is adopted to obtain the equivalent control signal u eq : is the parameter value of adaptive estimation, which is obtained by using an adaptive strategy based on the sliding mode surface of the integrated class potential function and the state model of the nonlinear electro-hydraulic servo system, as shown in the following formula: Wherein, γ1, γ2, γ3, γ4, and γ5 are adaptation laws. Step S5: Based on the sliding mode surface of the integrated class potential function, a switching control signal u is obtained using a fuzzy strategy n ; Step S6: Based on the equivalent control signal u eq and the switching control signal u n , obtain the final actual control signal u and output the actual control signal to the electro-hydraulic servo system.

2. The method according to claim 1, wherein Step S1 includes: S1.1: Set the desired motion trajectory through a fifth-degree polynomial, interpolate and segment the desired motion trajectory. The desired motion trajectory r is: where x0 is the starting point of the desired motion trajectory, x1 is the ending point of the desired motion trajectory, t b is the time elapsed from moving from x0 to x1, and t is time; S1.2: Obtain the actual motion trajectory y of the electro-hydraulic servo system. S1.3: Calculate the trajectory tracking errors e, e1, e2, and e3 based on the desired motion trajectory r and the actual motion trajectory y:

3. The method according to claim 1, characterized in that, In step S2, the state model of the nonlinear electro-hydraulic servo system includes: Wherein, u is the control input signal, e, e1, e2, and e3 are the trajectory tracking errors, a0, a1, a2, b, and f are coefficients related to the electro-hydraulic servo system, which are determined according to the actual working state. The expression is: where n = A2 / A1, A1 and A2 are the effective areas of the rodless chamber and the rod chamber of the hydraulic cylinder, β e is the effective bulk modulus, K t is the total flow pressure coefficient, K is the equivalent spring stiffness of the load, V is the total chamber volume, m is the equivalent mass of the moving parts, B c is the viscous damping coefficient, K a 、K b is the amplification coefficient, K q is the flow gain coefficient, F L is the equivalent load force.

4. The method according to claim 1, characterized in that, Step S5 includes: switching control signal u n The expression is: u n = ksgn(s) Wherein, sgn is the sign function; k is the gain coefficient of the switching control signal. Based on the sliding mode surface of the integrated-like potential function, the value of k is adjusted using fuzzy logic control rules to ensure good performance of the system.

5. The method according to claim 4, wherein Based on the sliding mode surface of the integrated-like potential function, adjusting the value of k using fuzzy logic control rules includes: S5.1: Define the input-output structure of the fuzzy controller: Design a two-dimensional fuzzy controller with two inputs and one output, taking the sliding mode surface s and its rate of change as inputs and the gain coefficient k of the switching control signal as the output. S5.2: Define the fuzzy sets of the fuzzy controller: The inputs are defined as 5 fuzzy sets: "Negative Big" (NB), "Negative Small" (NS), "Zero" (ZR), "Positive Small" (PS), and "Positive Big" (PB). The output is defined as seven fuzzy sets: "Negative Big" (NB), "Negative Medium" (NM), "Negative Small" (NS), "Zero" (ZR), "Positive Small" (PS), "Positive Medium" (PM), and "Positive Big" (PB). S5.3: Define the fuzzy universe of discourse of the fuzzy controller as the following formula: S5.4: Solve the fuzzy using the centroid method to obtain the gain coefficient k of the switching control signal.

6. According to the method described in claim 1, in step S6, the actual control signal u is: u = u eq + u n 。 7. A fuzzy sliding mode control device for an electro-hydraulic servo system integrating a class of potential functions, characterized in that, Including a processor and a storage medium; The storage medium is used to store instructions; The processor is used to operate according to the instructions to execute the steps of the method described in any one of claims 1 to 6.

8. A storage medium, on which a computer program is stored, characterized in that, When the computer program is executed by a processor, it implements the steps of the method according to any one of claims 1 to 6.

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