Fault-tolerant reconstruction method and system for multi-actuator hydraulic system based on load port independence

Abstract

The application discloses a kind of multi-actuator hydraulic system fault-tolerant reconstruction method and system based on load port independent frame, and relates to hydraulic system control technical field.The method is by constructing the symmetric topological connection matrix containing oil source, oil tank and each actuator load port, and establishes network connectivity authority based on fault information dynamic update matrix;According to the adjacent transfer principle and single-chamber borrowing constraint search oil supply and return path, open corresponding valve to build reconstructed hydraulic circuit;Using the independent control characteristics of load port, through the independent control valve of the load port of the transfer actuator not borrowed, make it continue to track the preset motion trajectory.The application realizes the online dynamic reconstruction of hydraulic circuit without adding physical redundancy, effectively suppresses the cavity pressure fluctuation and load disturbance through the functional decoupling of "one port flow, one port control", and significantly improves the fault-tolerant capability, operation reliability and synchronous operation continuity of multi-actuator hydraulic system.

Description

Technical Field

[0001] This application relates to the field of hydraulic system control technology, specifically to a fault-tolerant reconfiguration method and system for a multi-actuator hydraulic system based on load port independence. Background Technology

[0002] Hydraulic drive systems are crucial in high-radiation environments such as those used for maintaining robotic arms in nuclear power plant equipment, and their reliability directly impacts operational safety and continuity. In such environments, control valves are a major source of failure in hydraulic systems, especially complex components like proportional valves that are heavily reliant on electrical control; these are more prone to performance degradation or failure, leading to the actuator losing its driving capability.

[0003] Existing research on cross-actuator hydraulic reconfiguration largely focuses on flow connectivity, neglecting the issue of how the intermediate actuator continues its position control function after one of its chambers is borrowed as a reconfiguration channel. In traditional four-way valve structures, the two load ports are controlled by the same valve core, and the occupation of one chamber means that the actuator loses its position control capability. This invention, based on the inherent characteristic of the independent adjustment of the two load ports under an independent load port control framework, allows the borrowed chamber of the intermediate actuator to assume the function of a fault-tolerant channel, while the independent control valve of the load port corresponding to its other chamber continues to independently undertake the position tracking task of the actuator, thereby achieving decoupling of the fault-tolerant channel function and the position control function on the same actuator. In this process, disturbances such as the oil compressibility effect caused by pressure changes in the borrowed chamber and load changes are all suppressed by the single-port position closed loop.

[0004] There are already mature technical solutions for control valve fault diagnosis, such as methods based on valve core displacement feedback deviation detection, pressure and flow observer residual detection, and drive current anomaly detection. This invention does not involve improvements to the fault diagnosis methods themselves, nor does it rely on any specific diagnostic algorithm. The technical problem solved by this invention can be described as follows: given the hydraulic system topology, fault valve number information provided by existing fault diagnosis methods, and the original expected trajectory commands of each actuator, solve for a reconfigured valve control command set and control law redistribution scheme that can maintain the motion capability of the target actuator and keep the position tracking of the intermediate actuator.

[0005] It should be noted that there are already mature technical solutions for fault diagnosis of control valves (such as valve core displacement feedback deviation detection, pressure / flow observer residual detection, etc.), which are not within the scope of improvement of this invention; the technical problem solved by this invention is: given the faulty valve number information, how to achieve online reconstruction of the hydraulic circuit and maintain the continuity of the position control of the intermediate actuator after the fault occurs. Summary of the Invention

[0006] This application provides a fault-tolerant reconfiguration method and system for a multi-actuator hydraulic system based on independent load ports. It can solve the technical problems in the prior art, such as control valve failure causing the target actuator to lose power and the intermediate actuator losing position control due to the cavity being borrowed, resulting in the interruption of multi-actuator collaborative operation, and the high cost and poor flexibility of traditional redundancy solutions.

[0007] In a first aspect, this application provides a fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on load port independence, comprising the following steps: Obtain the system node set including the oil source interface, return oil tank interface and each actuator load port, and establish a symmetric topology connection matrix to identify the connectivity permission status of each node; The health status of each control valve is acquired in real time. When valve fault information is received, the matrix element corresponding to the faulty valve is set to a flow-prohibited state based on the symmetric topological connection matrix to obtain the fault connection matrix. Based on the fault connection matrix, the supply and return oil paths are searched according to the adjacent transfer principle and the single-cavity borrowing constraint, and the corresponding valves are opened to construct a reconstructed hydraulic circuit. Based on the independent control characteristics of the load port, the independent control valve of the load port that is not borrowed by the intermediate actuator is used to enable the intermediate actuator to continue to track its preset motion trajectory.

[0008] Furthermore, in the step of establishing the symmetric topological connection matrix, the symmetric topological connection matrix C is a (2n+2)×(2n+2) dimensional matrix, where n is the number of actuators; Matrix elements When the element is 1, it means that communication is allowed between node i and node j; when the element is 0, it means that communication is prohibited.

[0009] Furthermore, in the step of searching for the supply and return oil paths, the single-cavity borrowing constraint is specifically as follows: for any intermediate actuator, only one of its two load ports is allowed to be borrowed as the intermediate channel of the reconfiguration loop; during path screening, it is checked whether any intermediate actuator appears in the intermediate node set of the supply and return oil paths at the same time. If so, the path combination is determined to violate the constraint and is excluded.

[0010] Furthermore, the steps to ensure the intermediate actuator continues to track its preset motion trajectory specifically include: The independent control valve on the other side of the cavity of the transfer actuator is retained as the degree of freedom for position control. The opening of the independent control valve is adjusted with the preset motion trajectory issued by the upper controller before the failure of the actuator as the reference value and the real-time position feedback as the correction basis, so that the transfer actuator degenerates into a single-port position servo circuit.

[0011] Furthermore, in the step of adjusting the position servo closed loop via a single port, the following control law is adopted: ; In the formula, This is the opening command for the independent control valve on the opposite side cavity. for Positional deviation at any moment This refers to the positional deviation of the intermediate actuator, which is the difference between the preset motion trajectory and the real-time position feedback. For proportional gain, This is the integral gain.

[0012] Furthermore, in the step of searching for the oil supply and return paths, the oil supply path from the oil source interface through the cavity on one side of the adjacent actuator to the target load port, and the oil return path from the opposite side of the target load port through the cavity on one side of the adjacent actuator to the return oil tank interface are simultaneously searched; the adjacent actuators are interconnected through a bridged switching valve configured in a chain topology.

[0013] Furthermore, the load port independent control valve group includes a multi-position multi-way proportional valve, and the bridged switching valve group includes a two-position two-way switching valve; the element state update in the symmetric topology connection matrix only reflects the valve's on / off logic and does not limit the specific opening adjustment value of the multi-position multi-way proportional valve.

[0014] Furthermore, the step of acquiring the health status of each control valve in real time is implemented based on existing fault diagnosis methods, including but not limited to valve core displacement feedback deviation detection, pressure / flow observer residual detection, or drive current abnormality detection; the method uses the received fault valve number information as the input trigger condition and does not depend on a specific fault diagnosis algorithm.

[0015] Furthermore, during single-port position servo closed-loop adjustment, displacement disturbances caused by changes in cavity pressure, oil compressibility, and load are all incorporated into the feedback suppression as additional external disturbances by the single-port position servo closed-loop, thereby achieving position locking of the intermediate actuator.

[0016] Secondly, this application provides a multi-actuator hydraulic system based on a load-port independent frame, the system comprising: Oil source interface and oil return tank interface; At least two hydraulic actuators, each with two independent load ports; The load port independent control valve group is connected between the oil source interface, the return oil tank interface and the load port of each actuator, and is used to independently adjust the flow state of each load port; Bridged switching valve assemblies are arranged in a chain topology between the load ports on the same side of adjacent actuators; The controller is communicatively connected to the load port independent control valve group and is used to implement the fault-tolerant reconfiguration method steps of the multi-actuator hydraulic system based on load port independence as described above.

[0017] The beneficial effects of the technical solutions provided in this application include at least the following: By constructing a symmetric topology connection matrix and dynamically updating it based on fault information to establish network connectivity permissions, and combining the adjacent transfer principle and single-cavity borrowing constraint to search for supply and return oil paths to construct a reconstructed hydraulic circuit, and by utilizing the independent control characteristics of the load port to retain the independent control valve of the load port of the transfer actuator that has not been borrowed to maintain trajectory tracking, online dynamic reconstruction of the hydraulic circuit is achieved without adding physical redundancy. Through functional decoupling, the negative impact of pressure fluctuations and load disturbances of the borrowed cavity on the system accuracy is effectively suppressed, and the fault tolerance, operational reliability and synchronous operation continuity of the multi-actuator hydraulic system are significantly improved. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the three-degree-of-freedom hydraulic manipulator structure and hydraulic system according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the hydraulic system according to an embodiment of the present invention; Figure 3 This is a flowchart illustrating the fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on independent load ports, as described in this application. Figure 4 This is a schematic diagram of the standard position control principle of a single joint when there are no faults and it is not involved in fault-tolerant reconfiguration. Figure 5 This is a schematic diagram illustrating the decoupling principle of the functions of joint 1 and joint 2 after fault-tolerant reconstruction, where each cavity undertakes the fault-tolerant channel and maintains position control. Figure 6 This is a comparison diagram of the fault tolerance effect of the robotic arm joint trajectory in an embodiment of the present invention. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present application.

[0020] like Figure 1 As shown, the following description uses a three-degree-of-freedom hydraulic robotic arm as an example to fully illustrate the present invention, and provides numerical simulation verification results. The three joints are joint 1, joint 2, and joint 3, as follows: Figure 1As shown, the three joints are driven by hydraulic cylinder 1, hydraulic cylinder 2 and hydraulic cylinder 3 respectively.

[0021] Under the independent load port control framework, the system configures one three-position three-way proportional valve as an independent load port control valve for each joint hydraulic cylinder's A and B chambers, for a total of six independent load port control valves. The on / off state of these valves and their connection to the pressure source P and oil tank S is determined by the valve core position, thus achieving independent throttling regulation of the two load ports. In addition, one two-position two-way switching valve is installed between the load ports on the same side of adjacent joints as bridging valves, for a total of four bridging switching valves: a bridging switching valve is installed between chamber A of joint 1 and joint 2. A bridging valve is installed between cavity B of joint 1 and joint 2. A bridging valve is installed between cavity A of joint 2 and joint 3. A bridging valve is installed between cavity B of joint 2 and joint 3. Under normal operating conditions, all four bridged switching valves remain closed.

[0022] The principle of a complete hydraulic system is as follows: Figure 2 As shown in the figure, the connection relationships of the independent control valves, bridging switch valves, hydraulic pumps, relief valves and oil tanks for each load port are given by the figure.

[0023] Firstly, such as Figure 3 As shown, this application provides a fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on load port independence, including the following steps: Step S1: Obtain the system node set including the oil source interface, return oil tank interface and each actuator load port, and establish a symmetric topology connection matrix to identify the connectivity permission status of each node; Step S2: Obtain the health status of each control valve in real time. When valve fault information is received, based on the symmetric topology connection matrix, set the matrix element corresponding to the faulty valve to the flow-prohibited state to obtain the fault connection matrix. Step S3: Based on the fault connection matrix, search for the supply and return oil paths according to the adjacent transfer principle and the single-cavity borrowing constraint, and open the corresponding valves to construct a reconstructed hydraulic circuit; Step S4: Based on the independent control characteristics of the load port, use the independent control valve of the load port that is not borrowed by the intermediate actuator to make the intermediate actuator continue to track its preset motion trajectory.

[0024] This embodiment establishes network connectivity permissions by constructing a symmetric topology connection matrix and dynamically updating it based on fault information. It combines the principle of adjacent transfer and single-cavity borrowing constraints to search for supply and return oil paths to construct a reconstructed hydraulic circuit. It also utilizes the independent control characteristics of the load port to retain the independent control valve of the load port that has not been borrowed by the transfer actuator to maintain trajectory tracking. Online dynamic reconstruction of the hydraulic circuit is achieved without adding physical redundancy. Through functional decoupling, the negative impact of pressure fluctuations and load disturbances in the borrowed cavity on the system accuracy is effectively suppressed, significantly improving the fault tolerance, operational reliability, and synchronous operation continuity of the multi-actuator hydraulic system.

[0025] In one embodiment, step S1: Obtain a system node set including the oil source interface, the return oil tank interface, and the load ports of each actuator, and establish a symmetric topology connection matrix to identify the connectivity permission status of each node, specifically including the following steps: Step S11: Collect port information of all physical interfaces and actuators in the system to form a system node set.

[0026] Specifically, the oil source interface P, the return oil tank port S, and the load ports Ai and Bi on both sides of each hydraulic actuator are extracted and uniformly defined as network nodes, and a node set containing 2n+2 elements is constructed, where n is the number of actuators.

[0027] Step S12: Quantize and assign values ​​to the connectivity permissions between all pairs of nodes in the node set, and establish a symmetric topology connection matrix C.

[0028] Specifically, construct a (2n+2)×(2n+2) dimensional matrix C, with matrix elements... This is used to represent the permissible flow state of the valve between node i and node j, where 1 indicates permissible flow and 0 indicates prohibited flow. This includes three scenarios: no valve connection, valve jamming and closure failure, and controller-initiated shutdown command. The matrix structure is as follows, where each symbol... The elements represent the valve's allowed flow state at the corresponding position. Positions without valve connections have a constant value of 0. The structure of matrix C is as follows: Equation (1) The row and column order are both .

[0029] in, For pressure source interface, For oil return port, For actuator load port A, For actuator load port B, These are the connection paths between chamber A of the first, second, and third actuators and the pressure source interface P, respectively. These are the connection paths between chamber B of the first, second, and third actuators and the pressure source interface P, respectively. These are the connection passages between chamber A and return port S of the 1st, 2nd, and 3rd actuators, respectively; These are the connection passages between chamber B of the 1st, 2nd, and 3rd actuators and the oil return port S, respectively. These are interconnection paths between adjacent actuators (e.g., the A cavity of the first actuator is connected to the A cavity of the second actuator). These are the B-cavity interconnection paths between adjacent actuators.

[0030] This embodiment establishes a unified symmetric topology connection matrix, abstracting the complex hydraulic physical network into a standard mathematical language, thus realizing a digital description of the system's connectivity state. This modeling approach not only simplifies the subsequent fault injection and path search logic but also provides the controller with a standardized data structure, facilitating the modular portability and expansion of the algorithm.

[0031] In one embodiment, step S2: Real-time acquisition of the health status of each control valve; when valve fault information is received, based on the symmetric topology connection matrix, setting the matrix element corresponding to the faulty valve to a flow-prohibited state to obtain the fault connection matrix, specifically including the following steps: Step S21: Obtain the health status information of each control valve in real time based on existing fault diagnosis methods.

[0032] Specifically, it receives health status signals from existing methods such as valve core displacement feedback deviation detection, pressure / flow observer residual detection, and drive current anomaly detection.

[0033] Step S22: When valve fault information is received, the matrix elements corresponding to the zero-fault valves are set to zero, thus obtaining the fault connection matrix. .

[0034] Specifically, locate the row and column position of the faulty valve in the symmetric topological connection matrix C, set the matrix element at that position to 0 to indicate a flow-restricted state, and leave the other elements unchanged to obtain the faulty connection matrix. .

[0035] This embodiment uses matrix elements to dynamically respond to faults, completing logical updates of the system topology within milliseconds without altering the underlying control hardware. This matrix-based fault response mechanism effectively isolates the impact of faulty valves on the system, providing an accurate and real-time network model foundation for subsequent reconfiguration path searching.

[0036] In one embodiment, step S3: based on the fault connection matrix, searching for supply and return oil paths according to the adjacent transfer principle and single-cavity borrowing constraints, and opening the corresponding valves to construct a reconstructed hydraulic circuit, specifically includes the following steps: Step S31: Based on the fault connection matrix The reconstructed path is searched based on the principle of adjacent transfers, while the oil supply path and return path are also searched.

[0037] Specifically, the system identifies the oil supply path from pressure source P through the cavity on one side of the adjacent actuator to the target load port, and the oil return path from the opposite side of the target load port through the cavity on one side of the adjacent actuator to the return oil tank port S, and outputs preliminary candidate combinations of oil supply and return paths.

[0038] Step S32: Apply single-cavity borrowing constraints to the searched candidate path combinations for screening and verification, and eliminate illegal paths.

[0039] The single-cavity borrowing constraint stipulates that any intermediate actuator can only borrow one of its two load ports as a reconfiguration channel. If the A and B side bridging valves of the intermediate actuator are opened simultaneously, while the pressure source P supplies oil to the target cylinder through cavity A, cavity B will also be connected to an independent supply and return oil path. This causes the actuator to be driven by the pressure difference on both sides simultaneously, resulting in unexpected movement and failure to maintain position lock. Therefore, all candidate path combinations need to be checked. If both load ports (A / B ports) of any intermediate actuator appear at the intermediate node of the supply and return oil paths, the combination is judged to be in violation and discarded. Finally, a valid path that meets the constraints is output.

[0040] Step S33: Control the opening of the bridging switch valve and the independent control valve of the load port corresponding to the verified path, and construct a reconstructed hydraulic circuit that bypasses the faulty valve.

[0041] Specifically, taking the fault of VPA1 being stuck shut at t=10s as an example, the specific valve control command generated by the controller is as follows: Open control valve and bridging switch valve To establish a reconfigurable oil supply path from pressure source node P to target load port A1; Hold control valve The circuit is opened to maintain the return oil passage from the load port B1 to the oil tank node S; at the same time, the control valve VA2S is closed to prevent the oil supply flow from leaking into the oil tank through the transfer node A2.

[0042] This embodiment fundamentally avoids the risk of the transfer actuator going out of control due to simultaneous occupation of both cavities by introducing a single-cavity borrowing constraint, thus ensuring the safety of the reconfiguration process. Simultaneously, the adjacent transfer principle limits the search range, significantly reducing the computational complexity of path search, making online real-time reconfiguration possible and guaranteeing the continuity of multi-actuator collaborative operation.

[0043] In one embodiment, step S4: based on the independent control characteristics of the load port, using the independent control valve of the load port not borrowed by the transfer actuator to enable the transfer actuator to continue tracking its preset motion trajectory, specifically includes the following steps: Step S41: Identify the cavity on the other side of the intermediate actuator that is not occupied by the reconfigured loop, and establish the position control degree of freedom.

[0044] Specifically, after one side cavity of the intermediate actuator is used as a reconfiguration loop channel, the independent control valve of the load port corresponding to the other side cavity is retained as the actuator for position control, thus determining the available single-sided control valve resources of the intermediate actuator.

[0045] Step S42: Based on the preset motion trajectory and real-time position feedback, adjust the opening of the control valve to achieve trajectory tracking.

[0046] Specifically, the original expected trajectory sent by the upper-level controller before the fault occurred. As a reference value, the position feedback is based on the time t of the intermediate actuator. To provide a basis for calibration, the opening of the independent control valve is adjusted so that the intermediate actuator degenerates into a single-port position servo loop. The control law is: Equation (2) In the formula, This is the opening command for the independent control valve on the opposite side cavity. for Positional deviation at any moment This refers to the positional deviation of the intermediate actuator, which is the difference between the preset motion trajectory and the real-time position feedback. For proportional gain, This is the integral gain.

[0047] Among them, error Defined as: Equation (3) in, For the original expected trajectory, For real-time position feedback of the second actuator; Outputs action commands for driving and controlling the valve.

[0048] Step S43: The pressure fluctuation of the borrowed cavity is included as an external disturbance in the closed-loop suppression. The displacement disturbances caused by the pressure change of the borrowed cavity, the compressibility of the oil, and the load change are all included as additional external disturbances in the feedback suppression by the closed loop at this position. Specifically, by utilizing the feedback mechanism of the single-port position servo loop, the unexpected displacements caused by pressure changes, oil compressibility, and load changes in the borrowed cavity are uniformly regarded as disturbances and suppressed, thereby achieving stable maintenance of the position of the intermediate actuator.

[0049] This embodiment fully leverages the freedom of independent control of the load port, achieving functional decoupling of the "fault-tolerant channel" and "position control" on the same actuator. Through single-port position servo closed-loop, not only is the operation of the transfer actuator itself not interrupted, but nonlinear disturbances caused by the borrowed cavity (such as oil compressibility and load changes) are also uniformly incorporated into the feedback suppression, significantly improving the robustness and tracking accuracy of the system under reconfiguration conditions.

[0050] To clearly illustrate the evolution of the system connection state in this embodiment through the three stages of "before the fault occurs → fault occurrence → fault-tolerant reconfiguration", the connection matrix for each stage is given. , and This invention uses a 0 / 1 binary topology matrix: an element of 1 indicates that the valves between the node pairs are currently allowed to flow (open for on / off valves, and not closed for proportional valves; the specific opening degree is determined in real time by the valve's own control law and is not included in the topology matrix); an element of 0 indicates that flow is currently prohibited, including three situations: no physical valve connection, valve jamming and closure failure, or the controller actively issuing a closure command. The row and column order is { Elements related to joint 3 that are irrelevant to this reconstruction are set to 1 in the following matrix according to the "flowable" state.

[0051] Normal operation matrix before failure : Equation (4) Fault connection matrix at the moment of fault occurrence : Equation (5) in, This indicates that the node or its corresponding hydraulic connection has failed and has been isolated by the system; Working matrix after fault-tolerant reconstruction : Equation (6) in, This indicates the bridging path between the newly established intermediate actuator and the downstream actuator after fault-tolerant reconfiguration; The framed element is marked by arrive The changing valve status. It can be seen that this reconstruction only changed 2 pairs of symmetrical elements to complete the online reconstruction from the disabling of joint 1 to joint 1 continuing to be supplied with oil by P, joint 2 continuing to follow the original expected trajectory, and joint 1 and joint 2 operating synchronously.

[0052] The standard position control principle of a single joint when there are no faults and it is not involved in fault-tolerant reconfiguration is as follows: Figure 4As shown. After fault-tolerant reconstruction, the hydraulic drive and control relationship between joint 1 and joint 2 is as follows. Figure 5 As shown. Figure 5 The faulty load port independent control valve VPA1 is marked with a dashed box. The bridging switch valve VA12 between chambers A of hydraulic cylinders 1 and 2 is opened, forming a cross-actuator reconfiguration oil supply path P→A2→A1. Hydraulic cylinder 1 uses its remaining, unfaulty VB1S to perform throttling on the return side, with the position closed-loop controlled by a PI controller based on the feedback error of joint angle 1. Hydraulic cylinder 2 uses the load port independent control valve VB2S on the B2 side, with the position closed-loop controlled by a PI controller based on the feedback error of joint angle 2. (Comparison) Figure 4 and Figure 5 It can be clearly seen that after the fault-tolerant reconstruction, the oil supply side of joint 1 is changed from the direct path where the faulty valve is located to the transfer via the A chamber of the adjacent hydraulic cylinder 2. The hydraulic cylinder 2 is degenerated from the original dual-port joint control to a position servo circuit with only single-port throttling on the B2 side, that is, the function of "one port to undertake the fault-tolerant channel and one port to continue the position control" is decoupled.

[0053] Hydraulic cylinder 2, as the actuator of robotic arm joint 2, had its original desired trajectory sent by the upper controller before the malfunction occurred. During the reconstruction, the trajectory still needs to be tracked to maintain the multi-joint collaborative operation of the robotic arm. Since one of the borrowed cavities of hydraulic cylinder 2 has been used as a transfer channel in the oil supply circuit for the reconstruction path, its pressure is determined by the reconstruction circuit and can no longer be used for position control. Taking advantage of the independent adjustment of the two load ports under the independent control framework of the load ports, the position control function can still be undertaken by the independent control valve of the load port corresponding to the other cavity of hydraulic cylinder 2. For this reason, the position closed-loop control is implemented on the B2 cavity side control valve VB2S of hydraulic cylinder 2, and the control law is as shown in equations (2) and (3).

[0054] Three-joint position tracking effect, for example Figure 6 As shown. Figure 6 In the simulation, "Desired Position" refers to the original desired joint angle trajectory issued by the upper controller, "Proposed Method" refers to the measured joint angle response after applying the fault-tolerant reconfiguration control of this invention, and "No Fault Tolerance" refers to the measured joint angle response of the system after the application of the method of this invention and the jamming of the fault valve VPA1. The simulation injects a fault at t=10s, causing VPA1 (the independent control valve of the load port connecting P and A1) to jam and close; joint 2 steps from -120° to -60° at t=15s.

[0055] Figure 6 (a) shows the position tracking curve of joint 1; Figure 6 (b) shows the position tracking curve of joint 2; Figure 6 (c) shows the position tracking curve of joint 3.

[0056] Among them, joint 1 is the target actuator, joint 2 is the intermediate actuator, and joint 3 is the actuator that did not participate in the reconfiguration.

[0057] Joint 1 tracking performance such as Figure 6 As shown in (a). Before the fault occurs (t<10s), joint 1 moves from its initial position of approximately 60° to around 30°. At t=10s, the desired position jumps to 60°. At this time, VPA1 simultaneously injects a jamming and shut-off fault: In the absence of fault tolerance, joint 1 completely loses its driving capability, and the joint angle stagnates around 30°, unable to follow the step command; however, using the method of this invention, the controller immediately completes the reconstruction path search and valve control command reallocation, and the driving oil enters the A chamber of hydraulic cylinder 1 through the reconstruction path P→A2→A1. Joint 1 reaches the desired value in about 20s, and the steady-state error is controlled within ±1°, realizing the continuity of target joint position tracking under the condition of control valve failure.

[0058] Joint 2 tracking performance such as Figure 6 As shown in (b). Joint 2 at t=15s... 120° step jump 60°. Although cavity A of joint 2 has been borrowed as a reconstruction pathway, under the functional decoupling scheme of this invention, which uses "one channel to handle fault tolerance and another to continue position control," joint 2 is... By continuing to track its original expected trajectory through a single-port position closed loop, the integrity of the position control task of the transfer actuator was verified.

[0059] Joint 3 tracking performance such as Figure 6 As shown in (c). The valve in joint 3 did not malfunction, and its cavity was not used as a transfer channel, so its position closed loop maintained independent operation before and after the malfunction; Figure 6 In section (c), both "proposed method" and "no fault tolerance" can track the expected step command well, indicating that the reconstruction scheme of the present invention has no interference coupling to joints that are not involved in the reconstruction.

[0060] comprehensive Figure 6 It can be seen that, under the condition of the independent control valve VPA1 of joint 1 being stuck, the method of the present invention successfully achieved the position tracking recovery of joint 1, the trajectory tracking and maintenance of joint 2 under the condition of the borrowed cavity, and the interference-free independent operation of joint 3, and the overall collaborative operation capability of the three joints remained intact.

[0061] Simulation results show that even under extreme conditions where the control valve malfunctions and jams, this method can still control the position tracking error of the target actuator within a very small range (±1°) and perfectly maintain the trajectory tracking capability of the intermediate actuator. This proves the effectiveness of the "one-stop fault tolerance, one-stop position control" strategy, solves the pain point of traditional hydraulic systems being paralyzed upon failure, and greatly improves the reliability and survivability of the system in high-risk environments such as nuclear power plants and deep seas.

[0062] To evaluate the performance of the designed fault-tolerant control, the key physical parameters in this simulation are shown in Table 1: Table 1 Key Physical Parameters Secondly, this application provides a multi-actuator hydraulic system based on a load-port independent frame, the system comprising: Oil source interface and oil return tank interface; At least two hydraulic actuators, each with two independent load ports; The load port independent control valve group is connected between the oil source interface, the return oil tank interface and the load port of each actuator, and is used to independently adjust the flow state of each load port; Bridged switching valve assemblies are arranged in a chain topology between the load ports on the same side of adjacent actuators; The controller is communicatively connected to the load port independent control valve group and is used to implement the fault-tolerant reconfiguration method steps of the load port independent multi-actuator hydraulic system as described above.

[0063] In one embodiment, the controller is configured with a topology matrix management module, a path search module, and a position closed-loop control module; the topology matrix management module maintains the symmetric topology connection matrix and its derived fault connection matrix in real time; the path search module searches for oil supply paths and return paths simultaneously based on the fault connection matrix according to the adjacent transfer principle, and outputs a valve control command set after applying single-cavity borrowing constraints for screening; the position closed-loop control module independently runs a single-port position closed-loop control loop for each transfer actuator, and each loop operates in parallel without interfering with each other.

[0064] Thirdly, embodiments of this application also provide a readable storage medium.

[0065] This application stores a load-port-independent multi-actuator hydraulic system fault-tolerant reconfiguration program on a readable storage medium, wherein when the load-port-independent multi-actuator hydraulic system fault-tolerant reconfiguration program is executed by a processor, it implements the steps of the load-port-independent multi-actuator hydraulic system fault-tolerant reconfiguration method described above.

[0066] The method implemented when the fault-tolerant reconfiguration program for a multi-actuator hydraulic system based on independent load ports is executed can be referred to in various embodiments of the fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on independent load ports in this application, and will not be repeated here.

[0067] It should be noted that the sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0068] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the above embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device to execute the fault-tolerant reconfiguration method of the multi-actuator hydraulic system based on independent load ports described in the various embodiments of this application.

[0069] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on independent load ports, characterized in that, Includes the following steps: Obtain the system node set including the oil source interface, return oil tank interface and each actuator load port, and establish a symmetric topology connection matrix to identify the connectivity permission status of each node; The health status of each control valve is acquired in real time. When valve fault information is received, the matrix element corresponding to the faulty valve is set to a flow-prohibited state based on the symmetric topological connection matrix to obtain the fault connection matrix. Based on the fault connection matrix, the supply and return oil paths are searched according to the adjacent transfer principle and the single-cavity borrowing constraint, and the corresponding valves are opened to construct the reconstructed hydraulic circuit. The adjacent transfer principle means that the supply oil path from the oil source interface through the cavity on one side of the adjacent actuator to the target load port, and the return oil path from the opposite side of the target load port through the cavity on one side of the adjacent actuator to the return oil tank interface are searched simultaneously. The adjacent actuators are interconnected through the bridging switch valves set by the chain topology. The single-cavity borrowing constraint means that for any transfer actuator, only one of its two load ports is allowed to be borrowed as the transfer channel of the reconstructed circuit. If any transfer actuator appears in the intermediate node set of the supply and return oil paths at the same time, it is determined that the combination of supply and return oil paths violates the constraint and is excluded. Based on the independent control characteristics of the load port, the independent control valve of the load port that is not borrowed by the intermediate actuator is used to enable the intermediate actuator to continue to track its preset motion trajectory.

2. The fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on independent load ports according to claim 1, characterized in that, In the step of establishing the symmetric topological connection matrix, the symmetric topological connection matrix C is a (2n+2)×(2n+2) dimensional matrix, where n is the number of actuators; Matrix elements When the element is 1, it means that communication is allowed between node i and node j; when the element is 0, it means that communication is prohibited.

3. The fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on independent load ports according to claim 1, characterized in that, In the step of searching for the supply and return oil paths according to the adjacent transfer principle and the single-cavity borrowing constraint, the single-cavity borrowing constraint is specifically as follows: For any given intermediate actuator, only one of its two load ports is allowed to be used as the intermediate channel for the reconfiguration loop; During path filtering, check whether any intermediate actuator appears in the intermediate node set of both the oil supply path and the oil return path. If so, determine that the combination of the oil supply path and the oil return path violates the constraint and exclude it.

4. The fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on independent load ports according to claim 1, characterized in that, The specific steps to ensure that the intermediate actuator continues to track its preset motion trajectory include: The independent control valve on the other side of the cavity of the transfer actuator is retained as the degree of freedom for position control. The preset motion trajectory issued by the upper controller before the failure of the transfer actuator is used as the reference value and the real-time position feedback is used as the correction basis to adjust the opening of the independent control valve, so that the transfer actuator degenerates into a single-port position servo circuit.

5. The fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on independent load ports according to claim 4, characterized in that, In the step of converting the intermediate actuator into a single-port position servo loop and performing single-port position servo closed-loop regulation, the following control law is adopted: ； In the formula, This is the opening command for the independent control valve on the opposite side cavity. for Positional deviation at any moment This refers to the positional deviation of the intermediate actuator, which is the difference between the preset motion trajectory and the real-time position feedback. For proportional gain, This is the integral gain.

6. The fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on independent load ports according to claim 1, characterized in that, In the steps of searching for oil supply and return paths according to the principle of adjacent transfer and single-cavity borrowing constraints, the oil supply path from the oil source interface through the cavity on one side of the adjacent actuator to the target load port, and the oil return path from the opposite side of the target load port through the cavity on one side of the adjacent actuator to the return oil tank interface are searched simultaneously; the adjacent actuators are interconnected through a bridged switching valve configured in a chain topology.

7. The fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on independent load ports according to claim 1, characterized in that, The system node set is interconnected through load port independent control valve groups and bridged switching valve groups. The load port independent control valve groups include multi-position multi-way proportional valves, and the bridged switching valve groups include two-position two-way switching valves. The element state update in the symmetric topology connection matrix only reflects the valve on / off logic and does not limit the specific opening adjustment value of the multi-position multi-way proportional valves.

8. The fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on independent load ports according to claim 1, characterized in that, The step of acquiring the health status of each control valve in real time is based on existing fault diagnosis methods, including but not limited to valve core displacement feedback deviation detection, pressure / flow observer residual detection, or drive current abnormality detection. The fault-tolerant reconfiguration method for multi-actuator hydraulic systems based on independent load ports uses the received fault valve number information as the input trigger condition and does not depend on a specific fault diagnosis algorithm.

9. The fault-tolerant reconfiguration method for a multi-actuator hydraulic system based on independent load ports according to claim 4, characterized in that, When the transfer actuator degenerates into a single-port position servo loop and performs single-port position servo closed-loop regulation, the displacement disturbances caused by changes in cavity pressure, oil compressibility, and load changes are all uniformly incorporated into the feedback suppression as additional external disturbances by the single-port position servo closed loop, so as to achieve position locking of the transfer actuator.

10. A multi-actuator hydraulic system based on a load-port independent frame, characterized in that, The system includes: Oil source interface and oil return tank interface; At least two hydraulic actuators, each with two independent load ports; The load port independent control valve group is connected between the oil source interface, the return oil tank interface and the load port of each actuator, and is used to independently adjust the flow state of each load port; Bridged switching valve assemblies are arranged in a chain topology between the load ports on the same side of adjacent actuators; The controller is communicatively connected to the load port independent control valve group and is used to implement the fault-tolerant reconfiguration method steps of the multi-actuator hydraulic system based on load port independence as described in any one of claims 1 to 9.

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