Hydraulic servo system control method and hydraulic servo system

Abstract

The invention discloses a hydraulic servo system control method and a hydraulic servo system. The method comprises the steps that the total target driving force of a hydraulic cylinder in the hydraulic servo system is obtained; according to the total target driving force, first target driving force of a rodless cavity of the hydraulic cylinder and second target driving force of a rod cavity of the hydraulic cylinder are obtained; the first target driving force is converted into a first control signal, a first control valve is controlled according to the first control signal, and a rodless cavity outputs first actual driving force; and the second target driving force is converted into a second control signal, and the second control valve is controlled according to the second control signal, so that the rod cavity outputs a second actual driving force. By adopting the mode, the force control precision can be effectively improved, and the waveform distortion defect of a mechanical simulation system is reduced.

Description

Technical Field

[0001] The present invention relates to the field of hydraulic control, and in particular to a hydraulic servo system control method and a hydraulic servo system. Background Art

[0002] Hydraulic servo systems are widely used in high-dynamic force control scenarios, such as vehicle testing, structural loading, and engineering simulation, due to their high thrust, fast response, and high control precision. In particular, vehicle road excitation testing requires simulating the interaction between tires and the ground under various road conditions to reproduce the dynamic response characteristics of the vehicle under complex operating conditions. This places higher demands on the hydraulic loading system for control precision and response consistency.

[0003] In actual engineering applications, such as road simulators, bridge vibration simulators, and structural seismic test platforms, higher requirements are placed on the accuracy of force output. Existing control methods make it difficult to achieve precise control of simulators through hydraulic servo systems, especially in excitation scenarios such as high speed, high frequency, and complex impedance. The system exhibits large waveform distortion defects. Summary of the Invention

[0004] The object of the present invention is to provide a hydraulic servo system control method and a hydraulic servo system, so that the output force of the hydraulic cylinder is more stable.

[0005] To solve the above technical problems, an embodiment of the present invention provides a hydraulic servo system control method, comprising the following steps:

[0006] Obtain the total target driving force of the hydraulic cylinder in the hydraulic servo system;

[0007] According to the total target driving force, obtaining a first target driving force of the rodless chamber and a second target driving force of the rod chamber of the hydraulic cylinder;

[0008] converting the first target driving force into a first control signal, and controlling the first control valve according to the first control signal so that the rodless chamber outputs a first actual driving force;

[0009] The second target driving force is converted into a second control signal, and the second control valve is controlled according to the second control signal, so that the rod chamber outputs a second actual driving force.

[0010] The hydraulic servo system control method provided by an embodiment of the present invention takes the total target driving force of the hydraulic cylinder as the core control variable, and decomposes the total target driving force into the first target driving force of the rodless cavity and the second target driving force of the rod cavity according to the structural characteristics of the cavities on both sides of the hydraulic cylinder, and converts them into independent control signals for driving the corresponding first control valve and second control valve, thereby controlling the two cavities to realize their respective actual driving force outputs.

[0011] Through the above-mentioned method, the following beneficial technical effects are achieved:

[0012] First, compared with the traditional control mode based on displacement or speed setting, the present invention directly uses driving force as the main controlled variable, so that the control target is highly consistent with the test requirements, reducing the error introduced by indirect control variables, and improving the force control accuracy of the system. It is suitable for scenarios such as road excitation simulation with high-precision force loading requirements.

[0013] Secondly, the total driving force decomposition strategy can actively compensate for the asymmetric structure of the hydraulic cylinder in the control logic, balance the force differences between the rod cavity and the rodless cavity in forward and reverse motion, significantly improve the response consistency of the hydraulic cylinder during forward and reverse loading, and improve the symmetry problem during the loading process.

[0014] Thirdly, the rod chamber and the rodless chamber are independently adjusted by the first control valve and the second control valve, avoiding the disadvantages of dual-cavity coupling interference in traditional single-valve control, realizing independent controllability of dual-cavity pressure, and effectively improving system stability, control flexibility and dynamic response speed.

[0015] In summary, this control method establishes a closed-loop path of "target force → control signal → dual-valve control → actual driving force" from the perspective of force control. It has good control accuracy, system symmetry, and engineering applicability, providing a new and reliable hydraulic servo control solution for vehicle test loading systems.

[0016] In a possible embodiment, the total target driving force is distributed into a pressure distribution relationship between a first target driving force and a second target driving force. The pressure distribution method is obtained by jointly calculating a driving force equation and a pressure constraint equation, wherein the driving force equation is:

[0017] F=A1p1-A2p2

[0018] F is the total target driving force, P1 represents the first target driving pressure of the rodless cavity, P2 represents the second target driving pressure of the rod cavity, A1 and A2 represent the effective action areas of the rodless cavity and the rod cavity, respectively.

[0019] In a possible embodiment, the pressure constraint force equation is:

[0020] K=A1 p1+A2 p2

[0021] Or p1=K p2

[0022] Among them, K is an undetermined parameter, and K is greater than F.

[0023] In a possible embodiment, when the pressure constraint force equation is K=A1 p1+A2 p2, the pressure distribution algorithm of the rod cavity and the rodless cavity is as follows:

[0024]

[0025] In one possible embodiment, the complete allocation algorithm of the hydraulic servo system is as follows:

[0026]

[0027] Indicates the first actual driving force of the rodless cavity, represents the second actual driving force of the rod cavity, k1 represents the undetermined gain coefficient of the rodless cavity, k2 represents the undetermined gain coefficient of the rod cavity, u1 represents the first control signal, and u2 represents the second control signal.

[0028] In a possible embodiment, the first actual driving force is obtained and compared with the first target driving force to form a closed-loop feedback control;

[0029] and / or, obtaining the second actual driving force and comparing it with the second target driving force to form a closed-loop feedback control.

[0030] In a possible embodiment, the total target driving force is the dynamic driving force of the vehicle in a road excitation test.

[0031] In a possible embodiment, an actual motion displacement and an expected motion displacement of a target object, as well as an actual motion speed and an expected motion speed of the target object are obtained;

[0032] The total target driving force is obtained through the following impedance control algorithm:

[0033]

[0034] F represents the total target driving force, S represents the expected displacement, v represents the expected movement speed, Indicates the actual displacement, represents the actual motion speed, G represents the preset virtual drive stiffness, and C represents the preset virtual drive damping;

[0035] Acquiring a total actual driving force of the hydraulic cylinder, and adjusting the total target driving force according to the total actual driving force;

[0036] Repeat the above steps until the difference between the total target driving force and the total actual driving force is within a preset range.

[0037] The present application also provides a hydraulic servo system, comprising:

[0038] A hydraulic cylinder having a rod chamber and a rodless chamber;

[0039] a first control valve, the first control valve being in communication with the rodless chamber and being used to control a flow rate of liquid input into the rodless chamber;

[0040] a second control valve, the second control valve being in communication with the rod chamber and being used to control a flow rate of liquid input into the rod chamber;

[0041] a control system configured to obtain a total target driving force and decompose the total target driving force into a first target driving force and a second target driving force;

[0042] The control system is configured to convert the first target driving force into a first control signal, and control the first control valve according to the first control signal, so that the rodless chamber outputs a first actual driving force;

[0043] The control system is further configured to convert the second target driving force into a second control signal, and control the second control valve according to the second control signal, so that the rod chamber outputs a second actual driving force.

[0044] In a possible embodiment, the hydraulic servo system further includes:

[0045] a first sensor, the first sensor being used to detect the first actual driving force;

[0046] a second sensor, the second sensor being configured to detect the second actual driving force;

[0047] The control system is electrically connected to the first sensor and the second sensor, and is used to compare the first actual driving force with the first target driving force to form a closed-loop feedback control;

[0048] The control system is further configured to compare the second actual driving force with the second target driving force to form a closed-loop feedback control.

[0049] In a possible embodiment, the hydraulic servo system further includes a displacement sensor, which is used to detect the displacement of the hydraulic cylinder piston. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] One or more embodiments are exemplarily illustrated by pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Elements with the same reference numerals in the drawings are represented as similar elements. Unless otherwise stated, the figures in the drawings do not constitute proportional limitations.

[0051] The drawings described herein are used to provide further understanding of the present invention and constitute a part of this application. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute improper limitations on the present invention.

[0052] Description of reference numerals:

[0053] 100. Hydraulic servo system; 1. Hydraulic cylinder; 11. Rodless chamber; 12. Rod chamber; 2. First control valve; 21. First control signal; 3. Second control valve; 31. Second control signal; 4. Control system; 41. Overall control signal; 5. First sensor; 6. Second sensor; 7. Displacement sensor; 8. Hydraulic pump; 9. Relief valve;

[0054] Figure 1 Hydraulic servo system control schematic diagram;

[0055] Figure 2 This is the control flow chart of the hydraulic servo system;

[0056] Figure 3 It is a simulation diagram of the impedance control algorithm in the embodiment of the present application. DETAILED DESCRIPTION

[0057] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, each embodiment of the present invention will be described in detail below with reference to the accompanying drawings. However, those skilled in the art will appreciate that in each embodiment of the present invention, many technical details are provided to help readers better understand the present application. However, even without these technical details and various changes and modifications based on the following embodiments, the technical solutions claimed in the present application can still be implemented.

[0058] In the following description, for the purpose of illustrating the various disclosed embodiments, certain specific details are set forth in order to provide a thorough understanding of the various disclosed embodiments. However, those skilled in the relevant art will recognize that the embodiments may be practiced without one or more of these specific details. In other cases, well-known devices, structures, and techniques associated with this application may not be shown or described in detail to avoid unnecessarily obscuring the description of the embodiments.

[0059] Unless the context requires otherwise, throughout the specification and claims, the word "comprise" and variations such as "include" and "have" should be construed in an open, inclusive sense, that is, should be interpreted to mean "including, but not limited to."

[0060] The following will describe in detail various embodiments of the present invention in conjunction with the accompanying drawings to provide a clearer understanding of the objectives, features and advantages of the present invention. It should be understood that the embodiments shown in the accompanying drawings are not intended to limit the scope of the present invention, but are only intended to illustrate the essential spirit of the technical solution of the present invention.

[0061] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, the appearances of "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any manner in one or more embodiments.

[0062] As used in this specification and the appended claims, the singular forms "a," "an," and "the" include plural referents unless the context clearly dictates otherwise. It should be noted that the term "or" is generally employed in its sense including "and / or" unless the context clearly dictates otherwise.

[0063] In the following description, in order to clearly show the structure and working mode of the present invention, many directional words will be used for description, but words such as "front", "back", "left", "right", "outside", "inside", "outward", "inward", "up", and "down" should be understood as convenient terms and should not be understood as restrictive terms.

[0064] In some solutions, hydraulic servo control systems primarily rely on displacement or velocity control, aiming to keep the hydraulic cylinder moving along a predetermined trajectory. This approach typically relies on feedback from a displacement sensor for closed-loop regulation, with force output generated indirectly. While this type of control approach can meet motion control requirements in some operating conditions, it often proves ineffective in applications requiring precise force control.

[0065] In order to solve the above technical problems, the present application provides a hydraulic servo system control method, such as Figure 1 and Figure 2 As shown, the method specifically includes:

[0066] Obtain the total target driving force of hydraulic cylinder 1 in the hydraulic servo system;

[0067] According to the total target driving force, a first target driving force of the rodless chamber 11 and a second target driving force of the rod chamber 12 of the hydraulic cylinder 1 are obtained;

[0068] converting the first target driving force into a first control signal 21, and controlling the first control valve 2 according to the first control signal 21, so that the rodless chamber 11 outputs a first actual driving force;

[0069] The second target driving force is converted into a second control signal 31 , and the second control valve 3 is controlled according to the second control signal 31 , so that the rod chamber 12 outputs a second actual driving force.

[0070] It should be noted that in this embodiment of the present invention, "total target driving force" refers to the overall driving force that hydraulic cylinder 1 should output at a specific moment, as determined by control system 4 based on test task settings, control model calculations, or a preset loading trajectory. This driving force represents the net force that the hydraulic servo system should exert on the loaded object and is typically derived from the dynamic desired force generated by an impedance control algorithm or directly from force spectrum data input from a simulation platform.

[0071] This total target driving force, the core control variable of the control method in this embodiment of the present invention, does not rely on traditional position or velocity setting paths and can more directly reflect the actual force requirements of the test system. Control system 4 decomposes this total target driving force based on the structural characteristics of hydraulic cylinder 1 and distributes it to the rodless chamber 11 and the rod chamber 12, respectively, to form a first target driving force and a second target driving force. This in turn drives two independent control valves to adjust the pressure in each chamber, achieving an actual driving force at the output of hydraulic cylinder 1 that is consistent with the total target driving force.

[0072] By taking the "total target driving force" as the control core, the response accuracy, dynamic consistency and force output stability of the hydraulic servo system in complex force loading scenarios can be significantly improved, meeting the stringent requirements of high-performance simulation test platforms for driving force control.

[0073] The hydraulic servo system control method proposed in the embodiment of the present invention has the following technical effects:

[0074] First, by directly using the total target driving force as the total control signal 41 input, the traditional position control or pressure mapping path is eliminated, the control chain is significantly simplified, and the real-time performance and control accuracy of the force response are improved. It is particularly suitable for test platforms that require high dynamic force output, such as road simulators.

[0075] Secondly, the total target driving force is decomposed into the target driving forces of the rodless cavity 11 and the rod cavity 12 according to certain rules, and they are controlled independently, so that the control system 4 can actively adapt to the asymmetric structural characteristics of the hydraulic cylinder 1, effectively compensate for the mechanical imbalance caused by area differences, and significantly improve the symmetry and consistency of the hydraulic cylinder 1 during forward and reverse loading.

[0076] Again, the two cavities are regulated by independent control valves, avoiding the interference caused by traditional single-valve coupling control, so that the output forces of the rodless cavity 11 and the rod cavity 12 can be independently adjusted and precisely controlled, enhancing the system's flexibility, dynamic stability and anti-interference ability.

[0077] In summary, the present invention significantly improves the force control accuracy, system response consistency and engineering adaptability of the hydraulic servo system under an asymmetric structure by constructing a control closed-loop path of "target driving force → distribution → control signal → dual-cavity independent output", providing a reliable control basis for high-performance simulation experiments.

[0078] Regarding the above-mentioned "the hydraulic servo system in the embodiment of the present application can adapt to the asymmetric structural characteristics of the hydraulic cylinder 1 and effectively compensate for the mechanical imbalance problem caused by the area difference", a detailed explanation is as follows:

[0079] In a hydraulic servo system, the hydraulic cylinder 1 typically has an asymmetric structure, with one side of the piston connected to the piston rod (rod chamber 12) and the other side being a pure piston surface (rodless chamber 11). The effective force-bearing areas on both sides differ: the effective area of ​​rodless chamber 11 is larger than that of rod chamber 12. This structure can lead to significant mechanical imbalance in actual operation. Under identical pressure conditions, the thrust generated by the two chambers is inconsistent, resulting in asymmetric response characteristics of the hydraulic cylinder 1 during forward and reverse motion, manifesting as uneven loading, system offset, and even jitter or instability.

[0080] Existing control methods generally fail to fully consider the asymmetric structural characteristics of the hydraulic cylinder 1, especially under the single-valve control scheme. Since the pressures of the two chambers are affected by the same adjustment path, there is a strong coupling between the chambers, and the output forces on both sides cannot be accurately and independently adjusted, which further amplifies the mechanical deviation caused by the area difference.

[0081] To this end, the present invention proposes to decompose the total target driving force according to a specific rule into a first target driving force for the rodless cavity 11 and a second target driving force for the rod cavity 12. These are then converted into independent control signals, which drive two control valves to adjust the pressure in their corresponding cavities, respectively, so that the two cavities each bear an appropriate proportion of the driving force output. Because the present invention distributes the driving force through real-time model calculation, the driving force output of each cavity not only takes into account the difference in its own area, but also takes into account the overall mechanical balance of the system, effectively offsetting the bias caused by structural asymmetry.

[0082] In this way, even if the structural area of ​​hydraulic cylinder 1 is asymmetric, "physical symmetry" in force output can be achieved through logical "symmetrical distribution", fundamentally improving the consistency, balance and stability of the system during forward and reverse loading, solving the mechanical imbalance problem caused by area differences in traditional control methods, and enhancing the application capability of the hydraulic servo system in dynamic loading and high-precision simulation.

[0083] Furthermore, the following pressure distribution relationship is used to distribute the total target driving force into the first target driving force and the second target driving force. Specifically, the pressure distribution method is obtained by jointly calculating the driving force equation and the pressure constraint equation, where the driving force equation is:

[0084] F=A1p1-A2p2

[0085] F is the total target driving force, P1 represents the first target driving pressure of the rodless cavity 11, P2 represents the second target driving pressure of the rod cavity 12, A1 and A2 represent the effective action areas of the rodless cavity 11 and the rod cavity 12 respectively.

[0086] It should be noted that in a hydraulic system, the driving force output by the hydraulic cylinder is closely related to the liquid pressure in the cavity. According to basic mechanical principles, the driving force F acting on the piston end face of a cavity satisfies the following relationship with the liquid pressure P and effective force area A of the cavity:

[0087] F=P·A

[0088] F represents the force acting on the piston (unit: N), P represents the pressure of the hydraulic oil on the piston surface (unit: Pa or MPa), A represents the pressure area of ​​the piston (unit: m 2 ). Thus, under the premise of a certain piston area, adjusting the pressure of the hydraulic oil can achieve precise control of the output driving force. Therefore, after obtaining the first target driving pressure of the rodless chamber 11, the corresponding first target driving pressure can be obtained. Similarly, after obtaining the second target driving pressure of the rod chamber 12, the second target driving pressure can be obtained.

[0089] In addition, specifically, the pressure constraint force equation is:

[0090] K=A1 p1+A2 p2

[0091] Or p1=K p2

[0092] Among them, K is an undetermined parameter, and K is greater than F.

[0093] When the pressure constraint force equation is: K = A1 p1 + A2 p2, the pressure constraint force equation is substituted into the driving force equation to obtain the first target driving pressure of the rodless cavity 11 and the second target driving pressure of the rod cavity 12, as follows:

[0094]

[0095] When the pressure constraint force equation is: p1=Kp2, the pressure constraint force equation is substituted into the driving force equation to obtain the first target driving pressure of the rodless cavity 11 and the second target driving pressure of the rod cavity 12, as follows:

[0096]

[0097] The complete pressure distribution algorithm of the hydraulic servo system is as follows:

[0098]

[0099] represents the first actual driving pressure of the rodless chamber 11, represents the second actual driving pressure of the rod chamber 12 , k1 represents the undetermined gain coefficient of the rodless chamber 11 , k2 represents the undetermined gain coefficient of the rod chamber 12 , u1 represents the first control signal 21 , and u2 represents the second control signal 31 .

[0100] In this embodiment of the present invention, parameters k1 and k2 are used as control gain coefficients for closed-loop pressure control of the rodless and rodded chambers, respectively. Specifically, during operation, the hydraulic system uses pressure sensors to obtain the actual output pressures of the rodless and rodded chambers in real time and compares them with their respective target pressures to generate error signals. Based on the proportional gain parameters k1 and k2, the controller converts this pressure error into a control signal, which in turn adjusts the openings of the first and second control valves to achieve dynamic closed-loop regulation of the output pressures of each chamber.

[0101] Furthermore, in order to achieve a high degree of consistency between the output driving force of the hydraulic cylinder 1 and the total target driving force, the following operation can also be performed:

[0102] Obtain a first actual driving force, and compare the first actual driving force with the first target driving force to form a closed-loop feedback control; and / or obtain a second actual driving force, and compare it with the second target driving force to form a closed-loop feedback control. This embodiment realizes real-time monitoring and adjustment of the actual driving force through a closed-loop control strategy, thereby improving the response speed and accuracy of force control. The closed-loop feedback control is based on real-time measured pressure data, and by comparing the target force with the actual force, adjusts the control signal to achieve precise force tracking. The technology in this embodiment can effectively reduce force control errors and improve the stability and reliability of the system, especially in situations where high-precision force control is required, such as robot operation, to better complete tasks. In other embodiments, the problem of reduced force control effect in environments with large interference can also be solved by introducing multi-sensor fusion technology, such as combining displacement sensors and force sensors.

[0103] Specifically, the control system 4 is adjusted based on the pressure closed-loop control strategy, and the specific steps are as follows:

[0104] 1. The control system collects the feedback signals of the first sensor 5 and the second sensor 6 in real time to obtain the first actual driving pressure of the rodless cavity 11 and the second actual driving pressure of the rod chamber 12

[0105] 2. The control system precalculates and sets the first target driving pressure P1 of the rodless cavity 11 and the second target driving pressure P2 of the rod cavity 12 according to the total target driving force F, and compares them with the actual driving force to obtain an error signal:

[0106]

[0107] 3. The control system uses a proportional-integral-differential (PID) algorithm or other control strategies based on the above error to calculate the corresponding first control signal u1 and second control signal u2, which are used to control the opening degree of the first control valve 2 and the second control valve 3 respectively.

[0108] 4. The control system continues to perform the above feedback adjustment until the actual driving force of the rodless cavity 11 and the rod cavity 12 matches the target driving force, so that the resultant force output by the hydraulic cylinder 1 is approximately equal to the set total target driving force F, that is, the difference between the total actual driving force and the total target driving force is within the preset range.

[0109] Through the above closed-loop control process, the system can dynamically correct the output error to ensure that the force response of the hydraulic cylinder during loading is accurate and stable, thereby meeting the consistency and symmetry requirements for driving force control in high-precision simulation tests.

[0110] In the above process, the total target driving force is initially given by the control system. Subsequently, during the movement process, the total actual output force is fine-tuned through the information obtained by the first sensor 5 and the second sensor 6, so that the total actual output force can be basically consistent with the total target output force.

[0111] In an embodiment of the present invention, the first control signal u1 and the second control signal u2 are used to drive the first control valve 2 and the second control valve 3, respectively, and their function is to adjust the opening degree of the control valves, thereby accurately regulating the hydraulic flow and pressure entering the rodless chamber 11 and the rod chamber 12 of the hydraulic cylinder 1, and achieving the expected driving force. The control signals u1 and u2 are generally analog voltage signals or current signals, and their numerical values ​​determine the offset of the corresponding control valve spool, thereby adjusting the valve opening. The control valve opening affects the cavity flow and pressure changes, so that the rodless chamber 11 and the rod chamber 12 of the hydraulic cylinder 1 output the required first actual driving force and second actual driving force respectively. Through the above-mentioned closed-loop adjustment process, the control system can accurately regulate the dual-chamber output of the hydraulic cylinder 1, and achieve high-precision tracking and stable control of the driving force response.

[0112] Furthermore, as an alternative to the closed-loop control described above, to obtain a real-time total target driving force, a relationship between the total target driving force and the hydraulic cylinder's motion is established to achieve real-time control of the displacement trajectory of the hydraulic cylinder 1. Alternatively, the object's motion can be controlled using the following relationship between the total target driving force and motion:

[0113] Specifically, obtaining the actual motion displacement and expected motion displacement of the target object, as well as the actual motion speed and expected motion speed of the target object;

[0114] The total target driving force is obtained through the following impedance control algorithm:

[0115] F represents the total target driving force, S represents the expected displacement, v represents the expected movement speed, Indicates the actual displacement, represents the actual motion speed, G represents the preset virtual drive stiffness, and C represents the preset virtual drive damping;

[0116] Decomposing and obtaining a first target driving force of the rodless chamber 11 and a second target driving force of the rod chamber 12 of the hydraulic cylinder 1 according to the total target driving force;

[0117] The rodless chamber 11 is controlled to output a first actual driving force according to the first target driving force, and the rod chamber 12 is controlled to output a second actual driving force according to the second target driving force;

[0118] Obtaining a total actual driving force of the hydraulic cylinder 1, and adjusting the total target driving force according to the total actual driving force;

[0119] Repeat the above steps until the difference between the total target driving force and the total actual driving force is within a preset range.

[0120] In order to clarify the preset virtual drive stiffness G and the preset virtual drive damping C, as shown in Figure 3 As shown in the figure, it is assumed that a virtual moving object V performs ideal motion according to the design requirements, that is, the displacement and velocity signals are S and v respectively. Now use the virtual moving object V to drive the actual object T, and the two objects are connected by the following method: Figure 3 The spring G' is connected to the damper C', with spring stiffness G and damping coefficient C respectively. The driving force on the object T is determined by the motion error between the two objects. The driving force consists of two parts: the spring compression force and the damping force. The specific expression is:

[0121]

[0122] It is worth noting that better driving characteristics can be obtained by dynamically changing the damping and stiffness coefficients or designing other forms of nonlinear springs and damping forms. Currently, control theory provides a variety of solutions for designers to refer to.

[0123] The embodiment of the present invention introduces a driving force control algorithm based on impedance modeling, combined with dual-chamber force control of the hydraulic cylinder 1 and a closed-loop error adjustment mechanism, to achieve a stable, accurate, and smooth driving force response output by the hydraulic actuator in complex dynamic environments. The specific technical effects are analyzed as follows:

[0124] The impedance control algorithm can realize the compliance force response. Specifically, the present invention introduces the impedance control principle into the hydraulic system. The core idea is: according to the expected displacement S of the target object and the actual displacement Expected speed v and actual speed The dynamic deviation between them is used to construct the total target driving force for driving hydraulic cylinder 1 in real time:

[0125]

[0126] like Figure 3 As shown, the hydraulic servo system control method in the embodiment of the present application simulates a virtual "spring-damper" system, in which, Indicates "spring force", which can actively correct position errors by adjusting the G value. Represents "damping force." Adjusting C can mitigate velocity errors and suppress oscillations. Parameters G and C can be flexibly set to achieve varying degrees of compliance and responsiveness based on application requirements.

[0127] Therefore, the algorithm realizes the mapping relationship from error drive to force output, significantly enhancing the flexibility and safety of control. For example, in the field of robotics, the introduction of the above-mentioned impedance control method can make the movement of the robot more gentle and controllable.

[0128] An embodiment of the present invention further provides a hydraulic servo system, which includes: a hydraulic cylinder 1 , a first control valve 2 , a second control valve 3 and a control system 4 .

[0129] The hydraulic cylinder 1 has a rod chamber 12 and a rodless chamber 11; the first control valve 2 is connected to the rodless chamber 11, and is used to control the liquid flow input into the rodless chamber 11; the second control valve 3 is connected to the rod chamber 12, and is used to control the liquid flow input into the rod chamber 12; the control system 4 is used to obtain the total target driving force and decompose the total target driving force into the first target driving force and the second target driving force;

[0130] The control system 4 is configured to convert the first target driving force into a first control signal 21, and control the first control valve 2 according to the first control signal 21, so that the rodless chamber 11 outputs a first actual driving force;

[0131] The control system 4 is further configured to convert the second target driving force into a second control signal 31 , and control the second control valve 3 according to the second control signal 31 , so that the rod chamber 12 outputs a second actual driving force.

[0132] At the same time, the hydraulic servo system also includes a hydraulic pump 8 and a relief valve 9. The hydraulic pump 8 is the heart of the system and is responsible for providing the required oil pressure to the hydraulic cylinder 1; the relief valve 9 is a safety valve that ensures that the system pressure does not exceed the set value to prevent overload.

[0133] In one aspect of the present application, the hydraulic servo system further includes a first sensor 5 and a second sensor 6, wherein the first sensor 5 is used to detect a first actual driving force, and the second sensor 6 is used to detect a second actual driving force, wherein a control system 4 is electrically connected to the first sensor 5 and the second sensor 6, and the control system 4 is used to compare the first actual driving force with the first target driving force to form a closed-loop feedback control. The control system 4 also compares the second actual driving force with the second target driving force to form a closed-loop feedback control. This embodiment achieves real-time monitoring of the actual driving force through the integration of sensors, thereby improving the response speed and accuracy of force control. The sensor data is combined with the control system 4, and through a closed-loop feedback mechanism, precise force tracking is achieved. The technology in this embodiment can effectively reduce force control errors and improve the stability and reliability of the system, especially in situations where high-precision force control is required, such as precision instrument operation, to better complete tasks. In other embodiments, the problem of reduced force control effect due to environmental changes or fluid properties can be solved by adding additional sensor types, such as temperature sensors or flow sensors.

[0134] In one aspect of the present application, the hydraulic servo system further includes a displacement sensor 7 and a speed sensor. The displacement sensor 7 is used to detect the displacement of the piston of the hydraulic cylinder 1, and the speed sensor is used to detect the movement speed of the piston of the hydraulic cylinder 1. In this embodiment, the real-time monitoring of the displacement and speed of the piston of the hydraulic cylinder 1 is achieved through the integration of the displacement sensor 7, thereby improving the accuracy and response speed of motion control. The displacement sensor 7 and the speed sensor data are combined with the control system 4, and accurate tracking of displacement and speed is achieved through the feedback mechanism. The technology in this embodiment can effectively improve the motion control performance of the hydraulic servo system, especially in situations where high-precision displacement and speed control are required, and can better meet process requirements. In other embodiments, multi-sensor fusion technology can also be introduced, such as combining force sensors and displacement sensors 7, to improve the robustness of motion control and solve the problem of poor motion control effect under complex working conditions.

[0135] Description of working process:

[0136] In the hydraulic servo system of the present application, first, the control system 4 receives an instruction of the total control signal 41 input from the outside. Then, through the joint calculation of the driving force equation and the pressure constraint equation, the total target driving force is decomposed into the first target driving force of the rodless chamber 11 and the second target driving force of the rod chamber 12. Next, the control system 4 generates a first control signal 21 based on the first target driving force. After receiving the first control signal 21, the first control valve 2 adjusts the liquid flow of the rodless chamber 11 so that the rodless chamber 11 circuit outputs the first actual driving force; at the same time, a second control signal 31 is generated based on the second target driving force. After receiving the second control signal 31, the second control valve 3 adjusts the liquid flow of the rod chamber 12 so that the rod chamber 12 circuit outputs the second actual driving force. During the entire process, the first sensor 5 and the second sensor 6 detect the first actual driving force and the second actual driving force in real time and feed the data back to the control system 4. The control system 4 adjusts the control signal based on the feedback information to form a closed-loop control to ensure that the deviation between the actual driving force and the target driving force is within a preset range.

[0137] Furthermore, displacement sensor 7 monitors the displacement of the piston in hydraulic cylinder 1 in real time, while the velocity sensor monitors the velocity of the piston in hydraulic cylinder 1 in real time, providing real-time data support for the impedance motion control algorithm and enabling precise control of the motion trajectory of hydraulic cylinder 1. This entire operating process demonstrates the high degree of integration and intelligence of the technical solution of this application, effectively improving the control accuracy and response speed of the hydraulic servo system and meeting the requirements of high-precision force and motion control.

[0138] While preferred embodiments of the present invention have been described in detail above, it should be understood that aspects of the embodiments can be modified, if necessary, to employ aspects, features and concepts of the various patents, applications and publications to provide further embodiments.

[0139] These and other changes can be made to the embodiments in light of the above detailed description.In general, in the claims, the terms used should not be construed as limited to the specific embodiments disclosed in the specification and claims, but should be construed to include all possible embodiments along with the full scope of equivalents to which these claims are entitled.

[0140] Those skilled in the art will appreciate that the above embodiments are specific embodiments for implementing the present invention, and that in actual applications, various changes may be made thereto in form and detail without departing from the spirit and scope of the present invention.

Claims

1. A hydraulic servo system control method, characterized in that: Obtain the total target driving force of the hydraulic cylinder in the hydraulic servo system; According to the total target driving force, obtaining a first target driving force of the rodless chamber and a second target driving force of the rod chamber of the hydraulic cylinder; converting the first target driving force into a first control signal, and controlling the first control valve according to the first control signal so that the rodless chamber outputs a first actual driving force; The second target driving force is converted into a second control signal, and the second control valve is controlled according to the second control signal, so that the rod chamber outputs a second actual driving force.

2. The hydraulic servo system control method according to claim 1, characterized in that: The following pressure distribution relationship is used to distribute the total target driving force into the first target driving force and the second target driving force. The pressure distribution method is obtained by jointly calculating the driving force equation and the pressure constraint equation, where the driving force equation is: F=A1 p1-A2 p2 F is the total target driving force, P1 represents the first target driving pressure of the rodless cavity, P2 represents the second target driving pressure of the rod cavity, A1 and A2 represent the effective action areas of the rodless cavity and the rod cavity, respectively.

3. The hydraulic servo system control method according to claim 2, characterized in that: The pressure constraint force equation is: K=A1 p1+A2 p2 Or p1=K p2 Among them, K is an undetermined parameter, and K is greater than F.

4. The hydraulic servo system control method according to claim 3, characterized in that: When the pressure constraint force equation is K=A1 p1+A2 p2, the pressure distribution algorithm of the rod cavity and the rodless cavity is as follows:

5. The hydraulic servo system control method according to claim 4, characterized in that: The complete allocation algorithm of the hydraulic servo system is as follows: represents the first actual driving pressure of the rodless cavity, represents the second actual driving pressure of the rod cavity, k1 represents the undetermined gain coefficient of the rodless cavity, k2 represents the undetermined gain coefficient of the rod cavity, u1 represents the first control signal, and u2 represents the second control signal.

6. The hydraulic servo system control method according to claim 1, characterized in that: Obtaining the first actual driving force and comparing it with the first target driving force to form a closed-loop feedback control; and / or, obtaining the second actual driving force and comparing it with the second target driving force to form a closed-loop feedback control.

7. The hydraulic servo system control method according to claim 1, characterized in that: The total target driving force is the dynamic driving force of the vehicle during the road excitation test.

8. The hydraulic servo system control method according to claim 1, characterized in that: Acquiring an actual motion displacement and an expected motion displacement of a target object, as well as an actual motion speed and an expected motion speed of the target object; The total target driving force is obtained through the following impedance control algorithm: F represents the total target driving force, S represents the expected displacement, v represents the expected movement speed, Indicates the actual displacement, represents the actual motion speed, G represents the preset virtual drive stiffness, and C represents the preset virtual drive damping; Acquiring a total actual driving force of the hydraulic cylinder, and adjusting the total target driving force according to the total actual driving force; Repeat the above steps until the difference between the total target driving force and the total actual driving force is within a preset range.

9. A hydraulic servo system, characterized in that: include: A hydraulic cylinder having a rod chamber and a rodless chamber; a first control valve, the first control valve being in communication with the rodless chamber and being used to control a flow rate of liquid input into the rodless chamber; a second control valve, the second control valve being in communication with the rod chamber and being used to control a flow rate of liquid input into the rod chamber; a control system configured to obtain a total target driving force and decompose the total target driving force into a first target driving force and a second target driving force; The control system is configured to convert the first target driving force into a first control signal, and control the first control valve according to the first control signal, so that the rodless chamber outputs a first actual driving force; The control system is further configured to convert the second target driving force into a second control signal, and control the second control valve according to the second control signal, so that the rod chamber outputs a second actual driving force.

10. The hydraulic servo system according to claim 9, characterized in that: The hydraulic servo system further comprises: a first sensor, the first sensor being used to detect the first actual driving force; a second sensor, the second sensor being configured to detect the second actual driving force; The control system is electrically connected to the first sensor and the second sensor, and is used to compare the first actual driving force with the first target driving force to form a closed-loop feedback control; The control system is further configured to compare the second actual driving force with the second target driving force to form a closed-loop feedback control.

11. The hydraulic servo system according to claim 9, characterized in that: The hydraulic servo system further includes a displacement sensor, which is used to detect the displacement of the hydraulic cylinder piston.

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