Piston displacement control method and device of hydraulic actuator and train

Abstract

The invention provides a piston displacement control method and device of a hydraulic actuator and a train, and can be applied to the technical field of electro-hydraulic servo control. The method comprises the steps that the expected piston displacement, determined by a target tracking signal, of the hydraulic actuator at the t-th moment and the change characteristic value of the expected piston displacement, determined by a first-order derivative estimation signal of the target tracking signal, relative to the historical expected piston displacement are obtained; based on the change characteristic value, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage and the tracking error estimation parameter, an interference compensation value is determined, and the interference compensation value is a compensation value used for compensating uncertain interference in the hydraulic actuator. The tracking error estimation parameter is used for representing an estimation error for tracking the expected piston displacement; and based on the interference compensation value, the actual piston displacement, the change characteristic value and the expected piston displacement, determining a target control voltage for performing displacement control on the piston in the hydraulic actuator at the (t + T) th moment.

Description

Technical Field

[0001] The present disclosure relates to the field of electro-hydraulic servo control, and in particular, to a piston displacement control method, device, equipment, medium, program product, and train for a hydraulic actuator. Background Art

[0002] Hydraulic actuators are widely used in fields such as automation, aerospace, vehicle engineering, and ocean engineering, and are key components in modern construction machinery and automation systems. High-precision displacement tracking control of the piston in a hydraulic actuator is the key to determining its dynamic performance. In related technologies, a proportional-derivative control method is usually adopted, and the control voltage is adjusted through the feedback of the tracking error of the piston displacement, so as to achieve the control of the piston displacement.

[0003] In the process of implementing the concept of the present disclosure, the inventors found that there are at least the following problems in related technologies: Since the proportional-derivative control method uses tracking error feedback to achieve the control of the piston displacement, there are problems of hysteresis and large control errors. Summary of the Invention

[0004] In view of the above problems, the present disclosure provides a piston displacement control method, device, equipment, medium, program product, and train for a hydraulic actuator.

[0005] According to an aspect of the present disclosure, there is provided a piston displacement control method for a hydraulic actuator, including: obtaining an expected piston displacement of the hydraulic actuator at the t-th moment determined by a target tracking signal and a change characteristic value of the expected piston displacement compared with a historical expected piston displacement determined by a first-order derivative estimation signal of the target tracking signal; determining an interference compensation value based on the change characteristic value, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and a tracking error estimation parameter, where the interference compensation value is a compensation value for compensating for uncertainties and interferences in the hydraulic actuator, and the tracking error estimation parameter is used to characterize the estimation error of tracking the expected piston displacement; determining a target control voltage for controlling the displacement of the piston in the hydraulic actuator at the (t + T)-th moment based on the interference compensation value, the actual piston displacement, the change characteristic value, and the expected piston displacement.

[0006] Another aspect of the present disclosure provides a piston displacement control device for a hydraulic actuator, comprising: an acquisition module configured to acquire the desired piston displacement of the hydraulic actuator at the t-th moment determined by a target tracking signal and a change eigenvalue of the desired piston displacement compared with a historical desired piston displacement determined by a first derivative estimation signal of the target tracking signal; a compensation value determination module configured to determine an interference compensation value based on the change eigenvalue, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and a tracking error estimation parameter, wherein the interference compensation value is a compensation value for compensating for uncertainties and interferences in the hydraulic actuator, and the tracking error estimation parameter is used to characterize the estimation error of tracking the target tracking signal; and a voltage determination module configured to determine a target control voltage for controlling the displacement of the piston in the hydraulic actuator at the (t + T)-th moment based on the interference compensation value, the actual piston displacement, the change eigenvalue, and the desired piston displacement.

[0007] Another aspect of the present disclosure provides a train configured with a hydraulic actuator controlled by performing the piston displacement control method of the above-mentioned hydraulic actuator, and the hydraulic actuator is used to achieve dynamic coordinated control during the train's running process based on the displacement control of the piston in the hydraulic actuator.

[0008] Another aspect of the present disclosure provides an electronic device, comprising: one or more processors; a memory configured to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors are caused to execute the piston displacement control method of the above-mentioned hydraulic actuator.

[0009] Another aspect of the present disclosure further provides a computer-readable storage medium having executable instructions stored thereon, and when the instructions are executed by a processor, the processor is caused to execute the piston displacement control method of the above-mentioned hydraulic actuator.

[0010] Another aspect of the present disclosure further provides a computer program product comprising a computer program, and when the computer program is executed by a processor, the piston displacement control method of the above-mentioned hydraulic actuator is implemented.

[0011] The piston displacement control method of the hydraulic actuator disclosed in the present disclosure determines the change eigenvalue of the expected piston displacement at the t-th moment relative to the historical expected piston displacement through the first-order derivative estimation signal of the target tracking signal, which can improve the accuracy of the change eigenvalue. And the interference compensation value for the uncertainty interference of the hydraulic actuator is determined through the change eigenvalue, the actual piston displacement, the actual control voltage, and the tracking error estimation parameter at the t-th moment, so as to determine the target control voltage for controlling the piston displacement in the hydraulic actuator in the next sampling period through the interference compensation value, the change eigenvalue, the actual piston displacement, and the expected piston displacement. Since the uncertainty factors are actively estimated by using known information, and the influence of the uncertainty factors on the piston displacement control of the hydraulic actuator is eliminated through the interference compensation value when determining the target control voltage, at least part of the technical problems of large hysteresis and control error existing in the related technology are solved, and the technical effects of improving control accuracy and control robustness are achieved. Description of the Drawings

[0012] Through the following description of the embodiments of the present disclosure with reference to the drawings, the above content and other objects, features, and advantages of the present disclosure will become clearer. In the drawings:

[0013] Figure 1 Schematically shows an application scenario diagram of the piston displacement control method, device, equipment, medium, and program product of the hydraulic actuator according to an embodiment of the present disclosure;

[0014] Figure 2 Schematically shows a flowchart of the piston displacement control method of the hydraulic actuator according to an embodiment of the present disclosure;

[0015] Figure 3 Schematically shows a first comparison experimental diagram of the piston displacement control method of the hydraulic actuator according to an embodiment of the present disclosure and the related technology;

[0016] Figure 4 Schematically shows a second comparison experimental diagram of the piston displacement control method of the hydraulic actuator according to an embodiment of the present disclosure and the related technology;

[0017] Figure 5 Schematically shows a structural block diagram of the piston displacement control method of the hydraulic actuator according to another embodiment of the present disclosure;

[0018] Figure 6 Schematically shows a structural block diagram of the piston displacement control device of the hydraulic actuator according to an embodiment of the present disclosure; and

[0019] Figure 7 Schematically shows a block diagram of an electronic device suitable for implementing the piston displacement control method of the hydraulic actuator according to an embodiment of the present disclosure. Detailed Embodiments

[0020] Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are merely exemplary and are not intended to limit the scope of the present disclosure. In the following detailed description, for the sake of explanation, numerous specific details are set forth to provide a comprehensive understanding of the embodiments of the present disclosure. However, obviously, one or more embodiments can also be implemented without these specific details. In addition, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessarily confusing the concepts of the present disclosure.

[0021] The terms used herein are merely for describing specific embodiments and are not intended to limit the present disclosure. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0022] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art, unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0023] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include, but is not limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C, etc.).

[0024] It should be noted that the piston displacement control method of the hydraulic actuator of the present disclosure can be used in the field of electro-hydraulic servo control technology, and can also be used in any field other than the electro-hydraulic servo control technology field, such as: the computer technology field. The application field of the piston displacement control method of the hydraulic actuator of the present disclosure is not limited.

[0025] In the technical solution of the present invention, the user information involved (including but not limited to user personal information, user image information, user device information, such as location information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) are all information and data authorized by the user or fully authorized by all parties. And the processing of relevant data, such as collection, storage, use, processing, transmission, provision, disclosure, and application, all comply with the relevant laws, regulations, and standards of relevant countries and regions, take necessary confidentiality measures, do not violate public order and good customs, and provide corresponding operation entrances for users to choose to authorize or refuse.

[0026] In the research process, it is found that in a hot and humid climate environment, it is very likely to accelerate the aging of the rubber suspension components of high-speed trains, thereby affecting the vibration damping characteristics of the vehicle and further affecting the dynamic performance of the whole vehicle. In a mountainous environment, the horizontal and vertical profiles of the line are more complex, increasing the difficulty of controlling the track geometric irregularity and further exacerbating the wheel-rail excitation of high-speed trains. Therefore, the good running stability and safety of trains in complex environments such as hot and humid climate environments and mountainous environments have become problems that must be solved.

[0027] The hydraulic servo system is currently the most widely used solution in the bench test system of rail vehicles. As the core component of it, the hydraulic actuator demonstrates significant application value in scenarios requiring high-power output due to its advantages such as simple structure, stable power transmission, large output torque, and strong load-bearing capacity. The hydraulic actuator can generate powerful forces within a limited space, and the power transmission process is stable and efficient with a large power density, which makes it play a crucial role in the test loading process.

[0028] The high-precision displacement tracking control of the hydraulic actuator piston is a key factor determining its dynamic performance. In the position control system, it is necessary to accurately design the voltage value of the servo valve according to the piston displacement signal collected by the sensor in real time to automatically adjust the valve opening, and then achieve precise control of the piston displacement action.

[0029] Currently, the mainstream hydraulic actuator displacement tracking control method mainly adopts proportional-derivative control. This method does not need to rely on the accurate model of the hydraulic actuator and adjusts the servo valve voltage through error feedback. However, relying solely on feedback control has obvious hysteresis and control errors. In addition, due to the complex internal liquid dynamics of the hydraulic actuator, it is difficult to establish an accurate mathematical model, which also limits the further improvement of control accuracy.

[0030] In view of this, the embodiments of the present disclosure provide a piston displacement control method for a hydraulic actuator, including: obtaining the expected piston displacement of the hydraulic actuator at the t-th moment determined by the target tracking signal and the change eigenvalue of the expected piston displacement compared with the historical expected piston displacement determined by the first-order derivative estimation signal of the target tracking signal; determining an interference compensation value based on the change eigenvalue, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameter, where the interference compensation value is a compensation value used to compensate for the uncertain interference in the hydraulic actuator, and the tracking error estimation parameter is used to characterize the estimation error of tracking the expected piston displacement; determining the target control voltage for displacing the piston in the hydraulic actuator at the (t + T)-th moment based on the interference compensation value, the actual piston displacement, the change eigenvalue, and the expected piston displacement.

[0031] Figure 1Schematically shows an application scenario diagram of a piston displacement control method, device, equipment, medium, and program product for a hydraulic actuator according to an embodiment of the present disclosure.

[0032] As Figure 1 shown, the application scenario 100 according to this embodiment may include a controller 101, a network 102, a server 103, and a hydraulic actuator 104. The network 102 is used to provide a medium for communication links between the controller 101 and the server 103, between the controller 101 and the hydraulic actuator 104. The network 104 may include various connection types, such as wired, wireless communication links, or fiber optic cables, etc.

[0033] The controller 101 may execute the piston displacement control method of the hydraulic actuator, and a target control voltage can be obtained through the controller.

[0034] The server 103 may be a server that provides various services, such as a background management server (only for example) that provides support to the controller 101 during the determination of the target control voltage. The background management server may analyze and process the received data, and feedback the processing results to the controller.

[0035] The hydraulic actuator 104 may achieve displacement control of the piston in the hydraulic actuator 104 based on the target control voltage transmitted by the controller 101.

[0036] It should be noted that the piston displacement control method for the hydraulic actuator provided by the embodiments of the present disclosure can generally be executed by the server 103. Correspondingly, the piston displacement control device for the hydraulic actuator provided by the embodiments of the present disclosure can generally be set in the server 103. The piston displacement control method for the hydraulic actuator provided by the embodiments of the present disclosure can also be executed by a server or a server cluster different from the server 103 and capable of communicating with the controller 101 and / or the server 103. Correspondingly, the piston displacement control device for the hydraulic actuator provided by the embodiments of the present disclosure can also be set in a server or a server cluster different from the server 103 and capable of communicating with the controller 101 and / or the server 103.

[0037] It should be understood that Figure 1 the numbers of the controller, network, hydraulic actuator, and server are merely illustrative. According to actual needs, there can be any number of terminal devices, networks, and servers.

[0038] The following will be based on Figure 1 the described scenario, and will describe in detail the piston displacement control method for the hydraulic actuator of the disclosed embodiments through Figures 2 to 5 ...

[0039] Figure 2The flowchart of the piston displacement control method of the hydraulic actuator according to an embodiment of the present disclosure is schematically shown.

[0040] As Figure 2 shown, the method includes operation S210 to operation S230.

[0041] In operation S210, obtain the desired piston displacement of the hydraulic actuator at the t-th moment determined by the target tracking signal and the change eigenvalue of the desired piston displacement compared with the historical desired piston displacement determined by the first derivative estimation signal of the target tracking signal.

[0042] In operation S220, based on the change eigenvalue, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameter, determine the interference compensation value, where the interference compensation value is a compensation value for compensating the uncertainty interference in the hydraulic actuator, and the tracking error estimation parameter is used to characterize the estimation error of tracking the desired piston displacement.

[0043] In operation S230, based on the interference compensation value, the actual piston displacement, the change eigenvalue, and the desired piston displacement, determine the target control voltage for controlling the piston displacement in the hydraulic actuator at the (t + T)-th moment.

[0044] According to an embodiment of the present disclosure, the target tracking signal can be a signal that the piston displacement of the hydraulic actuator needs to track when controlling the piston displacement of the hydraulic actuator, and the target tracking signal can be a reference signal.

[0045] According to an embodiment of the present disclosure, the piston displacement control of the hydraulic actuator can be executed by a controller in the same environment as the hydraulic actuator. The same environment can be: also in a train, a robot, or other movable objects. The controller can be integrated inside the hydraulic actuator or outside the hydraulic actuator.

[0046] According to an embodiment of the present disclosure, both t and T can be real numbers greater than 0, and T is the sampling duration.

[0047] According to an embodiment of the present disclosure, the first derivative estimation signal of the target tracking signal can be obtained by estimating the first derivative of the target tracking signal. For example: using a method of combining low-pass filtering and numerical differentiation for first derivative estimation, or for another example: using Kalman filtering to achieve the first derivative estimation of the target tracking signal.

[0048] According to an embodiment of the present disclosure, the change eigenvalue can characterize the desired instantaneous speed of the piston or the instantaneous change rate of the piston displacement.

[0049] According to an embodiment of the present disclosure, the desired piston displacement at any moment can be determined through the target tracking signal.

[0050] According to an embodiment of the present disclosure, the interference compensation value can be determined by obtaining the actual piston displacement at the t-th moment of the hydraulic actuator, the actual control voltage at the t-th moment, and the tracking error estimation parameter. The tracking error estimation parameter can be an estimation parameter characterizing the tracking error when tracking the reference signal at the t-th moment.

[0051] According to an embodiment of the present disclosure, through the interference compensation value, the actual piston displacement, the change characteristic value, and the desired piston displacement, the interference compensation of the system uncertainty interference and the error feedback of the actual tracking error can be realized to determine the target control voltage at the final (t + 1)-th moment.

[0052] According to an embodiment of the present disclosure, by determining the change characteristic value of the desired piston displacement at the t-th moment relative to the historical desired piston displacement through the first-order derivative estimation signal of the target tracking signal, the determination accuracy of the change characteristic value can be improved. And the interference compensation value for the uncertainty interference of the hydraulic actuator is determined through the change characteristic value at the t-th moment, the actual piston displacement, the actual control voltage, and the tracking error estimation parameter, so as to determine the target control voltage for controlling the piston displacement in the hydraulic actuator in the next sampling period through the interference compensation value, the change characteristic value, the actual piston displacement, and the desired piston displacement. Since the uncertainty factor is actively estimated by using the known information, and the influence of the uncertainty factor on the piston displacement control of the hydraulic actuator is eliminated through the interference compensation value when determining the target control voltage, at least partially, the technical problems of large hysteresis and control error existing in the related art are solved, and the technical effects of improving the control accuracy and control robustness are achieved.

[0053] According to an embodiment of the present disclosure, the first-order derivative estimation signal is determined in the following manner.

[0054] The target tracking signal is filtered based on a low-pass filter to obtain the filtered target tracking signal; numerical differentiation is performed on the filtered target tracking signal to obtain the first-order derivative estimation signal.

[0055] According to an embodiment of the present disclosure, first, based on the attribute information of the hydraulic actuator, the executable frequency of the hydraulic actuator can be determined, and the target tracking signal is filtered based on a low-pass filter with the cut-off frequency being the executable frequency.

[0056] According to an embodiment of the present disclosure, the attribute information can be related attribute information of the hydraulic actuator itself, such as the frequency response characteristic of the servo valve in the hydraulic actuator, the flow rate and pressure of the hydraulic system.

[0057] According to an embodiment of the present disclosure, by combining the attribute information of multiple angles in the hydraulic actuator, the final executable frequency can be determined.

[0058] According to an embodiment of the present disclosure, the target tracking signal determines the executable frequency through the attribute information of the hydraulic actuator, improving the adaptability between the tracking signal and the hydraulic actuator. Then, a low-pass filter is applied to the target tracking signal to remove high-frequency noise in the target tracking signal, thereby reducing the interference of high-frequency signals on the derivative estimation. Numerical differentiation is performed on the filtered signal to achieve a more accurate estimation of the first-order derivative estimation signal.

[0059] According to an embodiment of the present disclosure, the target tracking signal can establish an estimation link for the first-order derivative of the target tracking signal through the following formula (1) to determine the first-order derivative estimation signal.

[0060] ; (1)

[0061] Where, is the state quantity of the first-order derivative estimation link of the target tracking signal at the th moment, is the first-order derivative of the state quantity of the first-order derivative estimation link of the target tracking signal at the th moment, is the estimated value of the target tracking signal of the first-order derivative estimation signal at the th moment, that is, the change eigenvalue, is the parameter to be adjusted in the first-order derivative estimation link of the target tracking signal, and R is a real number.

[0062] According to an embodiment of the present disclosure, by introducing a feedforward link for the first-order derivative estimation of the target tracking signal, the target tracking signal reduces the estimation pressure for subsequent uncertainty interference estimation to obtain the interference compensation value, improving the control lag in the related art designed only through displacement tracking error feedback.

[0063] According to an embodiment of the present disclosure, based on the change eigenvalue, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameter, determining the interference compensation value may include the following operations.

[0064] Based on the active disturbance rejection theory, using the change eigenvalue, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameter, construct an objective function; solve the objective function to obtain the interference compensation value.

[0065] According to an embodiment of the present disclosure, the core idea of the active disturbance rejection control (ADRC) is to achieve robust control of complex systems by real-time estimating and dynamically compensating internal and external disturbances in the system, such as model uncertainty, parameter changes, external disturbances, etc.

[0066] According to an embodiment of the present disclosure, the objective function can be as shown in the following formula (2).

[0067] ; (2)

[0068] where is the actual value of the tracking error of the piston in the hydraulic actuator at the th moment, is the estimated value of the tracking error of the piston displacement in the hydraulic actuator at the th moment, that is, the tracking error estimation parameter, is the first derivative of the tracking error estimation parameter, and there are multiple system parameters. , and are all system parameters. Specifically, is the inertia parameter of the hydraulic actuator, is the input gain parameter of the hydraulic actuator, is the bias parameter of the hydraulic actuator, is the actual piston displacement of the hydraulic actuator at the th moment, is the disturbance compensation value of the hydraulic actuator at the th moment, is the first derivative of the disturbance compensation value of the hydraulic actuator at the th moment, is the actual control voltage of the hydraulic actuator at the th moment, is an adjustable parameter, is a real number.

[0069] According to an embodiment of the present disclosure, the objective function can be an uncertainty observer for observing the uncertainty disturbance in the hydraulic actuator. can be the estimated value of the uncertainty disturbance, and the disturbance compensation value can be equal to the estimated value of the uncertainty disturbance.

[0070] According to an embodiment of the present disclosure, both the tracking error estimation parameter and the disturbance compensation value can be unknowns in the objective function, and the tracking error estimation parameter and the disturbance compensation value can be determined by setting the initial values of the tracking error estimation parameter and the disturbance compensation value and using the method of discrete solution. The method of discrete solution is, for example, the Euler method, the multi-step method, and so on.

[0071] According to an embodiment of the present disclosure, based on the active disturbance rejection theory, a target function is constructed by using relevant known information such as change eigenvalues, actual piston displacement, actual control voltage, and disturbances other than the uncertainty disturbance of the hydraulic actuator itself, such as tracking error estimation parameters, and the target function is solved to determine the disturbance compensation value. The estimation process of the system uncertainty disturbance can be quantified, and other disturbances can be considered during the process of compensating for the uncertainty disturbance, thereby improving the accuracy of determining the disturbance compensation value.

[0072] According to an embodiment of the present disclosure, based on the change eigenvalues, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameters, constructing a target function may include the following operations.

[0073] Input the desired piston displacement, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameters into the initial function to obtain an intermediate function; determine the adjustable parameters and system parameters corresponding to the actuator identifier based on the actuator identifier of the hydraulic actuator; input the adjustable parameters and system parameters into the intermediate function to obtain the target function.

[0074] According to an embodiment of the present disclosure, the initial function may be an initial function without parameter input.

[0075] According to an embodiment of the present disclosure, the actuator identifier and the corresponding adjustable parameters, as well as the system parameters, may be stored in the storage space to facilitate quick parameter determination.

[0076] According to an embodiment of the present disclosure, the adjustable parameters may be parameters with better tracking effects obtained by experimental adjustment in hydraulic actuators in similar scenarios. The similar scenarios may be scenarios where the installation position, installation scenario, etc. of the hydraulic actuator are the same.

[0077] According to an embodiment of the present disclosure, during the actual operation of the hydraulic actuator, the adjustable parameters can be continuously adjusted to determine more suitable adjustable parameters for the current scenario.

[0078] According to an embodiment of the present disclosure, by inputting the known information and estimation parameters into the initial function and obtaining the adjustable parameters and system parameters corresponding to the current scenario, a target function suitable for the current scenario can be obtained, thereby improving the accuracy of determining the subsequent disturbance compensation value.

[0079] According to an embodiment of the present disclosure, based on the system parameters of the hydraulic actuator and the estimated value of the first derivative of the target tracking signal, i.e., the characteristic change value, an error-driven uncertainty observer is established to actively estimate the uncertainty factors other than the known information, including the nonlinear characteristics of the hydraulic actuator, the estimated error of the first derivative of the reference signal, i.e., the tracking error estimation parameter, and other uncertainty effects. At the same time, in the voltage control design, an active uncertainty compensation design is adopted, which can eliminate the influence of various uncertainties on the hydraulic actuator system before they generate tracking errors, and improve the robustness and tracking accuracy of the hydraulic actuator displacement control system.

[0080] According to an embodiment of the present disclosure, the objective function may include a first sub-function and a second sub-function; the second sub-function represents the first derivative of the calculation sub-function for calculating the interference compensation value; the first sub-function is used to embed the calculation sub-function; the objective function is solved to obtain the interference compensation value, and the following operations may also be performed.

[0081] Determine the initial value of the preset tracking error estimation parameter, where the initial value corresponds to the adjustable parameter; input the initial value into the second sub-function to determine the target second sub-function; perform an inverse operation on the target second sub-function to obtain the calculation sub-function; input both the initial calculation function and the initial value into the first sub-function to determine the interference compensation value.

[0082] According to an embodiment of the present disclosure, taking formula (2) as an example, by inputting the initial value into the second sub-function, a target second sub-function with time as the unknown can be obtained, and by performing an inverse operation on the target second sub-function, the calculation sub-function can be obtained, so that the function representation of can be obtained, and by substituting the calculation sub-function into the first sub-function, the function representation of only containing the unknown time can be solved, so that by substituting time t into this function representation, the interference compensation value can be obtained.

[0083] According to an embodiment of the present disclosure, since the adjustable parameter and the initial value corresponding to the adjustable parameter are parameters with better tracking effects obtained through multiple experiments in the historical piston displacement control process, therefore, by setting the initial value of the tracking error estimation parameter corresponding to the adjustable parameter, the initial value and the adjustable parameter in the subsequent scenario can be determined through one determination process of the adjustable parameter, and since the initial value and the adjustable parameter compensate each other, the accuracy of the interference compensation value is ensured. The calculation process of the interference compensation value is simplified, and the calculation speed of the interference compensation value is improved.

[0084] According to an embodiment of the present disclosure, based on the interference compensation value, the actual piston displacement, and the desired piston displacement, determining the target control voltage for displacing the piston in the hydraulic actuator at the (t + T)-th moment may include the following operations.

[0085] Determine a feedforward control voltage based on an interference compensation value, an actual piston displacement, and a variation characteristic value; determine a feedback control voltage based on a desired piston displacement and the actual piston displacement; and determine a target control voltage for controlling the displacement of the piston in the hydraulic actuator at the (t + T)-th moment based on the feedforward control voltage and the feedback control voltage.

[0086] According to an embodiment of the present disclosure, a feedforward control voltage is determined through the interference compensation value, thereby performing feedforward compensation for various types of uncertainty interferences, and by combining the feedforward control voltage and the feedback control voltage determined by the desired piston displacement and the actual piston displacement, the control voltage is determined from two perspectives of interference compensation and feedback compensation, improving the robustness and tracking accuracy of the hydraulic actuator during piston displacement control.

[0087] According to an embodiment of the present disclosure, determining a feedforward control voltage based on an interference compensation value, an actual piston displacement, and a desired piston displacement may include the following operations.

[0088] Determine system parameters corresponding to the actuator identifier of the hydraulic actuator; perform a target operation on the system parameters, the interference compensation value, the actual piston displacement, and the desired piston displacement to obtain the feedforward control voltage.

[0089] According to an embodiment of the present disclosure, the calculation of the feedforward control voltage is determined through the following modeling process, specifically as shown in the following formulas (3) to (5). Among them, formula (3) is the system modeling process of the hydraulic actuator, establishing a relationship between the servo valve voltage of the hydraulic actuator and the piston displacement of the hydraulic actuator, and the servo valve voltage is the control voltage of the piston displacement. Formula (4) establishes a relationship for the piston displacement tracking error of the hydraulic actuator. Formula (5) establishes a relationship from the servo valve voltage to the piston displacement tracking error of the hydraulic actuator.

[0090] ; (3)

[0091] ; (4)

[0092] ; (5)

[0093] Among them, is the first derivative of the actual piston displacement of the hydraulic actuator at the moment, is the target tracking signal of the piston displacement of the hydraulic actuator at the moment, represents the modeling deviation of the hydraulic actuator, which is a type of uncertainty interference, is the first derivative of the actual value of the piston displacement tracking error of the hydraulic actuator at the moment, The first derivative of the target reference signal for the piston displacement of the hydraulic actuator at time .

[0094] According to an embodiment of the present disclosure, by combining the above formulas (1) to (5), the calculation formula of the feedforward control voltage can be determined as shown in the following formula (6).

[0095] ; (6)

[0096] wherein, is the feedforward control voltage.

[0097] According to an embodiment of the present disclosure, the feedforward control voltage combines system modeling information, an estimated value of the first derivative of the reference signal, and an estimated value of uncertainty during the calculation process, and establishes a feedforward control voltage with model information compensation, feedforward of the first derivative of the reference signal, and active compensation of uncertainty.

[0098] According to an embodiment of the present disclosure, by performing target operations on system parameters, interference compensation values, actual piston displacement, and change characteristic values, the interference compensation process and actual system parameters are combined, improving the calculation accuracy of the feedforward control voltage.

[0099] According to an embodiment of the present disclosure, based on the desired piston displacement and the actual piston displacement, determining the feedback control voltage may include the following operations.

[0100] Performing a subtraction operation on the desired piston displacement and the actual piston displacement to obtain the actual value of the tracking error; based on the actual value of the tracking error and a preset feedback gain parameter, determining the feedback control voltage at time t + 1.

[0101] According to an embodiment of the present disclosure, the feedback control voltage can be determined by the following formula (7).

[0102] ; (7)

[0103] wherein, is the feedback control voltage, is the feedback gain parameter to be adjusted, is the actual value of the tracking error.

[0104] According to an embodiment of the present disclosure, the feedback gain parameter is a parameter with better tracking effect determined through an actual experiment process. During the actual operation of the hydraulic actuator, the adjustable parameters can be continuously adjusted to determine more suitable adjustable parameters for the current scenario.

[0105] According to an embodiment of the present disclosure, by determining the actual value of the tracking error and combining the feedback gain parameter to determine the feedback control voltage, the calculation accuracy of the feedback control voltage can be improved.

[0106] According to an embodiment of the present disclosure, based on the feedforward control voltage and the feedback control voltage, determining the target control voltage for displacement control of the piston in the hydraulic actuator at the (t + T)th moment may include the following operations.

[0107] Perform an addition operation on the feedforward control voltage and the feedback control voltage to obtain the target control voltage.

[0108] According to an embodiment of the present disclosure, the target control voltage may be determined by the following formula (8).

[0109] ;(8)

[0110] According to an embodiment of the present disclosure, fusing the feedforward control voltage and the feedback control voltage through an addition operation can fully consider the target control voltage at different angles, and the addition operation is a relatively intuitive and convenient fusion method, which can improve the determination speed of the target control voltage.

[0111] According to an embodiment of the present disclosure, in some embodiments, taking the hydraulic actuator with system parameters of , , as an example, a specific implementation is carried out, and the specific steps are as follows.

[0112] According to an embodiment of the present disclosure, based on the system parameters of the hydraulic actuator, establish a relationship from the servo valve voltage of the hydraulic actuator to the piston displacement of the hydraulic actuator.

[0113] ;(9)

[0114] According to an embodiment of the present disclosure, introduce the displacement tracking error of the piston of the hydraulic actuator.

[0115] ;(10)

[0116] According to an embodiment of the present disclosure, establish a relationship from the servo valve voltage to the piston displacement tracking error of the hydraulic actuator.

[0117] ;(11)

[0118] According to an embodiment of the present disclosure, design an estimation link for the first derivative of the target tracking signal to obtain the first derivative estimation signal.

[0119] ;(12)

[0120] Among them, the adjustable parameters in the estimation link are selected as .

[0121] According to an embodiment of the present disclosure, based on the relationship between the servo valve voltage and the piston displacement tracking error of the hydraulic actuator, and combined with the parameter quantities obtained by modeling, an uncertainty observer driven by error based on the model information and the estimated value of the first derivative of the reference signal is established.

[0122] ;(13)

[0123] Among them, the adjustable parameters of the uncertainty observer are selected as .

[0124] According to an embodiment of the present disclosure, combining the model information, the estimated value of the first derivative of the reference signal, and the estimated value of the uncertainty, a feedforward design of the servo valve voltage of the hydraulic actuator with model information compensation, feedforward of the first derivative of the reference signal, and active compensation of the uncertainty is established.

[0125] ;(14)

[0126] According to an embodiment of the present disclosure, a feedback design quantity of the servo valve voltage of the hydraulic actuator based on the displacement tracking error is established.

[0127] ;(15)

[0128] Among them, the adjustable feedback gain parameters are selected as .

[0129] According to an embodiment of the present disclosure, by combining the feedforward design and the feedback design of the servo valve voltage of the hydraulic actuator, the final target control voltage is obtained as shown below.

[0130] ;(16)

[0131] According to an embodiment of the present disclosure, by separating the first derivative estimation link of the reference signal and the uncertainty observer, independent parameter adjustment of each link can be realized, and the internal coupling effect of the controller design can be reduced.

[0132] Figure 3 Schematically shows a first comparative experimental diagram of the piston displacement control method of the hydraulic actuator according to an embodiment of the present disclosure and related technologies.

[0133] As Figure 3 shown, respectively show the tracking results of the piston displacement control method of the hydraulic actuator of the present disclosure for a 1 Hz sinusoidal target tracking signal and the tracking results of a related technology such as the proportional-derivative control method for the target tracking signal.

[0134] Figure 4 Schematically shows a second comparative experimental diagram of the piston displacement control method of a hydraulic actuator according to an embodiment of the present disclosure and related technologies.

[0135] As Figure 4 shown, respectively shows the tracking results of the piston displacement control method of the hydraulic actuator of the present disclosure for a 2 Hz sinusoidal target tracking signal and the tracking results of using related technologies such as the proportional-derivative control method for the target tracking signal.

[0136] According to an embodiment of the present disclosure, the piston displacement control method of the hydraulic actuator of the present disclosure is abbreviated as the method of the present disclosure in Figure 3 and Figure 4 below.

[0137] According to an embodiment of the present disclosure, it can be known from Figure 3 and Figure 4 that the proportional-derivative control method will have a certain lag and amplitude deviation when tracking the target tracking signal: when tracking a 1 Hz sinusoidal target tracking signal, the average tracking error is 0.54 mm; when tracking a 2 Hz sinusoidal target tracking signal, the average tracking error is 0.73 mm. The piston displacement control method of the hydraulic actuator of the present disclosure has higher control accuracy and provides a faster tracking control result without using the nonlinear model of the hydraulic actuator: when tracking a 1 Hz sinusoidal target tracking signal, the average tracking error is 0.24 mm; when tracking a 2 Hz sinusoidal target tracking signal, the average tracking error is 0.19 mm.

[0138] Figure 5 Schematically shows a structural block diagram of the piston displacement control method of a hydraulic actuator according to another embodiment of the present disclosure.

[0139] As Figure 5 shown, after obtaining the system parameters of the hydraulic actuator, respectively construct an uncertainty observer and input it into the determination of the feedforward control voltage of the hydraulic actuator containing model information compensation, first-order derivative feedforward of the reference signal, and uncertainty active compensation.

[0140] According to an embodiment of the present disclosure, the target tracking signal is respectively input into the estimation link of the first-order derivative of the target tracking signal and the determination process of the feedback control voltage of the hydraulic actuator.

[0141] According to an embodiment of the present disclosure, the target tracking signal can be transmitted to the determination process of the feedback control voltage of the hydraulic actuator, or the target tracking signal can be transmitted to the determination process of the feedback control voltage of the hydraulic actuator.

[0142] According to an embodiment of the present disclosure, the first derivative estimation signal can be obtained through the above-mentioned estimation link of the first derivative of the target tracking signal. And it is transmitted to the process of determining the feedforward control voltage of the hydraulic actuator; and after the uncertainty observer obtains the disturbance compensation value, it is also input to the process of determining the feedforward control voltage, so as to obtain the feedforward control voltage at the target moment.

[0143] According to an embodiment of the present disclosure, while determining the feedforward control voltage of the hydraulic actuator, a feedback design based on the displacement error can be performed to obtain the feedback control voltage, so that the feedforward design and the feedback design are combined to obtain the target control voltage, that is, the servo valve voltage.

[0144] According to an embodiment of the present disclosure, in the case where the target control voltage is obtained by a controller other than the hydraulic actuator, the target control voltage can be transmitted to the hydraulic actuator, so that the servo valve in the hydraulic actuator controls the flow rate and direction of the hydraulic oil in the hydraulic actuator through the target control voltage, and further adjusts the position of the piston in the hydraulic actuator.

[0145] According to an embodiment of the present disclosure, the target control voltage can be transmitted to the uncertainty observer at the same time, so as to facilitate the determination of the disturbance compensation value at the next moment.

[0146] According to an embodiment of the present disclosure, the present disclosure also provides a train, and the train is configured with a hydraulic actuator controlled by executing a piston displacement control method of the hydraulic actuator, and the hydraulic actuator is used for controlling based on the displacement of the piston in the hydraulic actuator to achieve dynamic coordination control during the driving process of the train.

[0147] According to an embodiment of the present disclosure, after obtaining the target control voltage, the target control voltage can be sent to the hydraulic actuator, so that the servo valve in the hydraulic actuator precisely regulates the flow rate and direction of the hydraulic oil in the hydraulic actuator, and further realizes the control of the piston position, so as to achieve dynamic coordination control such as braking control, suspension control, dynamic stability control, door and connection device control during the driving process of the train.

[0148] For example: the brake cylinder pressure can be adjusted in real time through the piston displacement to ensure that the braking force matches the vehicle speed and load, and avoid wheel locking or uneven braking. Or the stiffness and damping of the suspension system can be changed through the piston displacement to absorb the vibration caused by track irregularities.

[0149] Based on the above piston displacement control method of the hydraulic actuator, the present disclosure also provides a piston displacement control device of the hydraulic actuator. The following will be combined with Figure 6 This device will be described in detail.

[0150] Figure 6A structural block diagram of a piston displacement control device of a hydraulic actuator according to an embodiment of the present disclosure is schematically shown.

[0151] As Figure 6 shown, the piston displacement control device 600 of the hydraulic actuator in this embodiment includes an acquisition module 610, a compensation value determination module 620, and a voltage determination module 630.

[0152] The acquisition module 610 is configured to acquire the expected piston displacement of the hydraulic actuator at the t-th moment determined by the target tracking signal and the change characteristic value of the expected piston displacement compared with the historical expected piston displacement determined by the first-order derivative estimation signal of the target tracking signal.

[0153] The compensation value determination module 620 is configured to determine an interference compensation value based on the change characteristic value, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameter, where the interference compensation value represents the compensation value for the uncertainty interference or external interference in the hydraulic actuator, and the tracking error estimation parameter is used to represent the estimation error of tracking the target tracking signal.

[0154] The voltage determination module 630 is configured to determine a target control voltage for controlling the piston displacement in the hydraulic actuator at the (t + T)-th moment based on the interference compensation value, the actual piston displacement, the change characteristic value, and the expected piston displacement.

[0155] According to an embodiment of the present disclosure, the compensation value determination module 620 includes: a construction sub-module and a solution sub-module.

[0156] The construction sub-module is configured to construct an objective function based on the active disturbance rejection theory, using the change characteristic value, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameter.

[0157] The solution sub-module is configured to solve the objective function to obtain the interference compensation value.

[0158] According to an embodiment of the present disclosure, the construction sub-module includes: a first construction unit, a parameter determination unit, and a second construction unit.

[0159] The first construction unit is configured to input the change characteristic value, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameter into an initial function to obtain an intermediate function.

[0160] The parameter determination unit is configured to determine adjustable parameters and system parameters corresponding to the actuator identifier based on the actuator identifier of the hydraulic actuator.

[0161] The second construction unit is configured to input the adjustable parameters and system parameters into the intermediate function to obtain the objective function.

[0162] According to an embodiment of the present disclosure, a piston displacement control device 600 of a hydraulic actuator includes: a differentiation module and a filtering module.

[0163] The filtering module is configured to filter a target tracking signal based on a low-pass filter to obtain a filtered target tracking signal.

[0164] The differentiation module is configured to perform numerical differentiation on the filtered target tracking signal to obtain a first derivative estimation signal.

[0165] According to an embodiment of the present disclosure, a voltage determination module 630 includes: a first voltage determination sub-module, a second voltage determination sub-module, and a third voltage determination sub-module.

[0166] The first voltage determination sub-module is configured to determine a feedforward control voltage based on an interference compensation value, an actual piston displacement, and a change characteristic value.

[0167] The second voltage determination sub-module is configured to determine a feedback control voltage based on a desired piston displacement and an actual piston displacement.

[0168] The third voltage determination sub-module is configured to determine a target control voltage for controlling the displacement of the piston in the hydraulic actuator at the (t + T)-th moment based on the feedforward control voltage and the feedback control voltage.

[0169] According to an embodiment of the present disclosure, the first voltage determination sub-module includes: a determination unit and a first operation unit.

[0170] The determination unit is configured to determine system parameters corresponding to the actuator identifier of the hydraulic actuator.

[0171] The first operation unit is configured to perform a target operation on the system parameters, the interference compensation value, the actual piston displacement, and the change characteristic value to obtain a feedforward control voltage.

[0172] According to an embodiment of the present disclosure, the second voltage determination sub-module includes: a second operation unit and a feedback voltage determination unit.

[0173] The second operation unit is configured to perform a subtraction operation on the desired piston displacement and the actual piston displacement to obtain an actual tracking error value.

[0174] The feedback voltage determination unit is configured to determine a feedback control voltage based on the actual tracking error value and a preset feedback gain parameter.

[0175] According to an embodiment of the present disclosure, the third voltage determination sub-module includes: a third operation unit.

[0176] The third operation unit is configured to perform an addition operation on the feedforward control voltage and the feedback control voltage to obtain a target control voltage.

[0177] According to an embodiment of the present disclosure, any one or more of the acquisition module 610, the compensation value determination module 620, and the voltage determination module 630 may be combined and implemented in one module, or any one of them may be split into multiple modules. Alternatively, at least part of the functions of one or more of these modules may be combined with at least part of the functions of other modules and implemented in one module. According to an embodiment of the present disclosure, at least one of the acquisition module 610, the compensation value determination module 620, and the voltage determination module 630 may be at least partially implemented as a hardware circuit, such as a field programmable gate array (FPGA), a programmable logic array (PLA), a system on chip, a system on substrate, a system on package, an application specific integrated circuit (ASIC), or any other reasonable manner that can integrate or package circuits, etc., implemented by hardware or firmware, or implemented in any one of the three implementation manners of software, hardware, and firmware, or in an appropriate combination of any several of them. Alternatively, at least one of the acquisition module 610, the compensation value determination module 620, and the voltage determination module 630 may be at least partially implemented as a computer program module, and when the computer program module is run, the corresponding functions may be executed.

[0178] Figure 7 A block diagram of an electronic device suitable for implementing a piston displacement control method of a hydraulic actuator according to an embodiment of the present disclosure is schematically shown.

[0179] As Figure 7 shown, the electronic device 700 according to an embodiment of the present disclosure includes a processor 701, which can perform various appropriate actions and processes according to a program stored in a read-only memory (ROM) 702 or a program loaded from a storage section 708 into a random access memory (RAM) 703. The processor 701 may include, for example, a general microprocessor (such as a CPU), an instruction set processor, and / or a related chipset, and / or a dedicated microprocessor (such as an application specific integrated circuit (ASIC)), etc. The processor 701 may also include on-board memory for caching purposes. The processor 701 may include a single processing unit or multiple processing units for performing different actions of the method flow according to an embodiment of the present disclosure.

[0180] In the RAM 703, various programs and data required for the operation of the electronic device 700 are stored. The processor 701, the ROM 702, and the RAM 703 are connected to each other via a bus 704. The processor 701 performs various operations of the method flow according to the embodiments of the present disclosure by executing the programs in the ROM 702 and / or the RAM 703. It should be noted that the programs can also be stored in one or more memories other than the ROM 702 and the RAM 703. The processor 701 can also perform various operations of the method flow according to the embodiments of the present disclosure by executing the programs stored in one or more memories.

[0181] According to an embodiment of the present disclosure, the electronic device 700 may further include an input / output (I / O) interface 705, and the input / output (I / O) interface 705 is also connected to the bus 704. The electronic device 700 may further include one or more of the following components connected to the I / O interface 705: an input portion 706 including a keyboard, a mouse, etc.; an output portion 707 including, for example, a cathode ray tube (CRT), a liquid crystal display (LCD), etc., and a speaker, etc.; a storage portion 708 including a hard disk, etc.; and a communication portion 709 including a network interface card such as a LAN card, a modem, etc. The communication portion 709 performs communication processing via a network such as the Internet. A drive 710 is also connected to the I / O interface 705 as needed. A removable medium 711, such as a magnetic disk, an optical disk, a magneto-optical disk, a semiconductor memory, etc., is installed on the drive 710 as needed so that a computer program read from it can be installed into the storage portion 708 as needed.

[0182] The present disclosure also provides a computer-readable storage medium, which may be included in the device / apparatus / system described in the above embodiments; or may exist separately without being assembled into the device / apparatus / system. The above computer-readable storage medium carries one or more programs, and when the one or more programs are executed, the method according to the embodiments of the present disclosure is implemented.

[0183] According to an embodiment of the present disclosure, the computer-readable storage medium may be a non-volatile computer-readable storage medium, for example, it may include but is not limited to: portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the above. In the present disclosure, the computer-readable storage medium may be any tangible medium that contains or stores a program, and this program can be used by or in combination with an instruction execution system, apparatus, or device. For example, according to an embodiment of the present disclosure, the computer-readable storage medium may include the above-described ROM 702 and / or RAM 703 and / or one or more memories other than ROM 702 and RAM 703.

[0184] An embodiment of the present disclosure also includes a computer program product, which includes a computer program that contains program code for executing the method shown in the flowchart. When the computer program product runs in a computer system, the program code is used to enable the computer system to implement the piston displacement control method of the hydraulic actuator provided by the embodiment of the present disclosure.

[0185] When the computer program is executed by the processor 701, it executes the above functions defined in the system / apparatus of the embodiment of the present disclosure. According to an embodiment of the present disclosure, the above-described systems, apparatuses, modules, units, etc. can be implemented by computer program modules.

[0186] In one embodiment, the computer program can rely on tangible storage media such as optical storage devices and magnetic storage devices. In another embodiment, the computer program can also be transmitted and distributed in the form of a signal on a network medium, and is downloaded and installed through the communication part 709, and / or installed from the removable medium 711. The program code included in the computer program can be transmitted by any suitable network medium, including but not limited to: wireless, wired, etc., or any suitable combination of the above.

[0187] In such an embodiment, the computer program can be downloaded and installed from the network through the communication part 709, and / or installed from the removable medium 711. When the computer program is executed by the processor 701, it executes the above functions defined in the system of the embodiment of the present disclosure. According to an embodiment of the present disclosure, the above-described systems, devices, apparatuses, modules, units, etc. can be implemented by computer program modules.

[0188] According to embodiments of the present disclosure, program code for executing the computer programs provided by the embodiments of the present disclosure can be written in any combination of one or more programming languages. Specifically, these computing programs can be implemented using high-level procedural and / or object-oriented programming languages, and / or assembly / machine languages. The programming languages include, but are not limited to, programming languages such as Java, C++, Python, the "C" language, or similar programming languages. The program code can be executed entirely on the user's computing device, partially on the user's device, partially on a remote computing device, or entirely on a remote computing device or server. In cases involving a remote computing device, the remote computing device can be connected to the user's computing device through any type of network, including a local area network (LAN) or a wide area network (WAN), or it can be connected to an external computing device (e.g., by using an Internet service provider to connect through the Internet).

[0189] The flowcharts and block diagrams in the accompanying drawings illustrate the possible architectures, functions, and operations of systems, methods, and computer program products according to various embodiments of the present disclosure. In this regard, each block in the flowchart or block diagram can represent a module, a program segment, or a part of code that contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the blocks can occur in a different order than that marked in the accompanying drawings. For example, two consecutive blocks shown can actually be executed substantially in parallel, and they can sometimes be executed in the reverse order, depending on the functions involved. It should also be noted that each block in the block diagram or flowchart, and combinations of blocks in the block diagram or flowchart, can be implemented using a dedicated hardware-based system for performing the specified functions or operations, or can be implemented using a combination of dedicated hardware and computer instructions.

[0190] Those skilled in the art can understand that the features recited in the various embodiments and / or claims of the present disclosure can be combined or combined in various ways, even if such combinations or combinations are not explicitly recited in the present disclosure. In particular, without departing from the spirit and teachings of the present disclosure, the features recited in the various embodiments and / or claims of the present disclosure can be combined and combined in various ways. All such combinations and / or combinations fall within the scope of the present disclosure.

[0191] The embodiments of the present disclosure have been described above. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present disclosure. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present disclosure is defined by the appended claims and their equivalents. Without departing from the scope of the present disclosure, those skilled in the art can make various substitutions and modifications, and all such substitutions and modifications should fall within the scope of the present disclosure.

Claims

1. A method for controlling the piston displacement of a hydraulic actuator, characterized in that, Including: Obtaining an expected piston displacement of a hydraulic actuator at the t-th moment determined by a target tracking signal and a change eigenvalue of the expected piston displacement compared with a historical expected piston displacement determined by a first-order derivative estimation signal of the target tracking signal; Based on the change eigenvalue, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and a tracking error estimation parameter, determining an interference compensation value, where the interference compensation value is a compensation value for compensating for an uncertain interference in the hydraulic actuator, and the tracking error estimation parameter is used to characterize an estimation error of tracking the expected piston displacement; Based on the interference compensation value, the actual piston displacement, the change eigenvalue, and the expected piston displacement, determining a target control voltage for controlling the piston displacement in the hydraulic actuator at the (t + T)-th moment.

2. The method according to claim 1, wherein The determining the interference compensation value based on the change eigenvalue, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameter includes: Based on the active disturbance rejection theory, using the change eigenvalue, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameter to construct an objective function; Solving the objective function to obtain the interference compensation value.

3. The method according to claim 2, wherein The constructing the objective function based on the change eigenvalue, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameter includes: Inputting the change eigenvalue, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and the tracking error estimation parameter into an initial function to obtain an intermediate function; Based on the actuator identifier of the hydraulic actuator, determining an adjustable parameter and a system parameter corresponding to the actuator identifier; Inputting the adjustable parameter and the system parameter into the intermediate function to obtain the objective function.

4. The method according to claim 1, characterized in that, The first-order derivative estimation signal is determined by the following method: Filtering the target tracking signal based on a low-pass filter to obtain a filtered target tracking signal; Performing numerical differentiation on the filtered target tracking signal to obtain the first-order derivative estimation signal.

5. The method according to claim 1, characterized in that The determining the target control voltage for controlling the piston displacement in the hydraulic actuator at the (t + T)-th moment based on the interference compensation value, the actual piston displacement, the change eigenvalue, and the expected piston displacement includes: Based on the interference compensation value, the actual piston displacement, and the change eigenvalue, determining a feedforward control voltage; Based on the expected piston displacement and the actual piston displacement, determining a feedback control voltage; Based on the feedforward control voltage and the feedback control voltage, determining the target control voltage for controlling the piston displacement in the hydraulic actuator at the (t + T)-th moment.

6. The method according to claim 5, characterized in that The determining the feedforward control voltage based on the interference compensation value, the actual piston displacement, and the expected piston displacement includes: Determining a system parameter corresponding to the actuator identifier of the hydraulic actuator; Perform a target operation on the system parameters, the interference compensation value, the actual piston displacement, and the change characteristic value to obtain the feedforward control voltage.

7. The method according to claim 5, wherein Determining the feedback control voltage based on the desired piston displacement and the actual piston displacement includes: Perform a subtraction operation on the desired piston displacement and the actual piston displacement to obtain the actual value of the tracking error; Determine the feedback control voltage based on the actual value of the tracking error and a preset feedback gain parameter.

8. The method according to claim 5, wherein Determining the target control voltage for controlling the displacement of the piston in the hydraulic actuator at the (t + T)-th moment based on the feedforward control voltage and the feedback control voltage includes: Perform an addition operation on the feedforward control voltage and the feedback control voltage to obtain the target control voltage.

9. A piston displacement control device for a hydraulic actuator, comprising: An acquisition module configured to acquire the desired piston displacement of the hydraulic actuator at the t-th moment determined by a target tracking signal and the change characteristic value of the desired piston displacement compared with the historical desired piston displacement determined by the first-order derivative estimation signal of the target tracking signal; A compensation value determination module configured to determine an interference compensation value based on the change characteristic value, the actual piston displacement of the hydraulic actuator at the t-th moment, the actual control voltage, and a tracking error estimation parameter, where the interference compensation value is a compensation value for compensating for the uncertainty interference in the hydraulic actuator, and the tracking error estimation parameter is used to characterize the estimation error of tracking the target tracking signal; A voltage determination module configured to determine a target control voltage for controlling the displacement of the piston in the hydraulic actuator at the (t + T)-th moment based on the interference compensation value, the actual piston displacement, the change characteristic value, and the desired piston displacement.

10. A train, wherein the train is configured with a hydraulic actuator controlled by performing the method according to any one of claims 1 to 8, and the hydraulic actuator is used to achieve dynamic coordinated control of the train during driving based on the displacement control of the piston in the hydraulic actuator.

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