A compression loading instantaneous unloading protection control method and system

Abstract

The application discloses a compression loading instantaneous unloading protection control method and system, and relates to the technical field of compression loading safety control. The method comprises the following steps: acquiring loading state data in a compression loading process; determining the compression energy storage state of the current compression loading process and the bearing stability state of a loading object according to the loading state data; predicting the loading risk in the protection window based on the response characteristics of an actuator and the loading state data; determining an unloading strategy and generating a controlled unloading trajectory when the instantaneous unloading trigger condition is met; controlling at least two unloading execution actions to cooperatively execute the instantaneous unloading protection according to the controlled unloading trajectory; and correcting the controlled unloading trajectory and / or subsequent protection control parameters according to unloading feedback information. Thus, the loading instability risk can be identified in advance, the controllability of the compression energy storage release process can be improved, and the influence of the actuator response delay and unloading rebound impact on the safety of equipment can be reduced.

Description

Technical Field

[0001] This application relates to the field of compressive loading safety control technology, and in particular to a method and system for instantaneous unloading protection control under compressive loading. Background Technology

[0002] Compressive loading equipment is widely used in material mechanical property testing, geotechnical engineering experiments, concrete component inspection, structural load-bearing capacity verification, and industrial pressure loading. This type of equipment typically applies a continuously increasing compressive load to the specimen or tested component via hydraulic cylinders, electro-servo loading mechanisms, or other pressure actuators. Load sensors, displacement sensors, and pressure sensors collect mechanical response data during the loading process to obtain test results such as compressive strength, deformation characteristics, failure process, and bearing limit. During compressive loading, as the load gradually increases, compressive energy continuously accumulates in the specimen, fixture, loading frame, and actuator. Especially in high-stiffness specimens, brittle material specimens, or large-tonnage loading equipment, when the specimen experiences crack propagation, local buckling, eccentric instability, or instantaneous failure, the accumulated compressive energy may be released in a very short time, leading to safety risks such as sudden load changes, specimen fragmentation, fixture impact, loading mechanism rebound, or equipment damage.

[0003] Existing compression loading equipment typically employs safety control methods such as load threshold protection, displacement threshold protection, pressure upper limit protection, emergency stop protection, or pressure relief valve protection. For example, when the loading force exceeds a preset upper limit, the displacement exceeds the allowable range, or the hydraulic pressure reaches a protection threshold, the control system cuts off the loading command, stops the servo drive, or opens the pressure relief valve to reduce the risk of continued loading. However, these methods are mostly passive protections after exceeding limits, usually using whether the current detection value exceeds a fixed threshold as the triggering basis. They are difficult to reflect in a timely manner the rapid decay of the sample's load-bearing capacity, the sudden drop in equivalent stiffness, acoustic emission, or vibration impact, which are precursors to damage. At the same time, there is a certain response delay in the opening of hydraulic valves, the response of servo motors, the release of oil pressure, and the return stroke of mechanical transmission. Even if the control system issues a stop or depressurization command, the loading system may still continue to input energy into the sample or fixture for a short period of time. In addition, simple depressurization or emergency stop methods usually do not distinguish between energy storage on the sample side, energy storage on the loading mechanism side, and energy storage on the actuator side. They also do not select appropriate unloading paths according to different failure modes such as brittle failure, ductile crushing, local buckling, and off-center load instability. This can easily lead to problems such as unloading too slowly, resulting in insufficient protection, or unloading too quickly, causing rebound displacement, clamp loosening, and secondary impact.

[0004] Therefore, in the safety protection and control of compression loading equipment, the following issues urgently need to be addressed: delayed identification of loading instability risk, difficulty in accurately controlling the compression energy storage release process, significant impact of actuator response delay, and the tendency of instantaneous unloading process to trigger rebound impact. Summary of the Invention

[0005] This application provides a method and system for instantaneous unloading protection control under compressive loading, which aims to solve the problems in the safety protection control of compressive loading equipment, such as delayed identification of loading instability risk, difficulty in accurately controlling the compression energy storage release process, significant impact of actuator response delay, and easy occurrence of rebound impact during instantaneous unloading.

[0006] A first aspect is a method for instantaneous stress relief protection control under compressive loading, the method comprising: Obtain loading status data during the stress loading process; The compression energy storage state and the load-bearing stability state of the loading object are determined based on the loading state data during the current compressive loading process. Based on the response characteristics of the actuator and the loading status data, the loading risk within the protection window is predicted; If the instantaneous unloading triggering condition is met based on the compressed energy storage state, the load-bearing stability state, and the loading risk, an unloading strategy matching the current compressive loading state is determined. A controlled unloading trajectory is generated based on the unloading strategy; At least two unloading actions are controlled according to the controlled unloading trajectory to perform instantaneous unloading protection in a coordinated manner. Based on the unloading feedback information during the instantaneous unloading protection process, the controlled unloading trajectory and / or subsequent protection control parameters are corrected.

[0007] Optionally, in the above scheme, obtaining the loading status data during the compressive loading process includes: Collect raw loading data during the compressive loading process. The raw loading data includes at least two of the following: loading force data, loading displacement data, loading speed data, actuator status data, and load object failure signs data. The original loaded data is processed for time synchronization and validity to obtain synchronized loaded data; Generate a loading force change sequence, a displacement change sequence, an actuator response sequence, and a failure sign sequence based on the synchronous loading data; The loading force change sequence, the displacement change sequence, the actuator response sequence, and the damage sign sequence are used as the loading state data.

[0008] Optionally, in the above scheme, determining the compression storage state of the current compressive loading process based on the loading state data includes: The loading work change information of the current compressive loading process is determined based on the loading force change sequence and the displacement change sequence; The stiffness information of the loaded object, the stiffness information of the loading mechanism, and the compression status information of the actuator are determined based on the loading status data. Based on the loading power change information, the loading object stiffness information, the loading mechanism stiffness information, and the actuator compression state information, determine the energy storage state on the loading object side, the energy storage state on the loading mechanism side, and the energy storage state on the actuator side. The compression energy storage state is obtained based on the energy storage state of the loading object side, the energy storage state of the loading mechanism side, and the energy storage state of the actuator side.

[0009] Optionally, in the above scheme, determining the load-bearing stability state of the loaded object based on the load state data includes: Generate load-displacement relationship information based on the loading force change sequence and the displacement change sequence; The equivalent stiffness change information is determined based on the load-displacement relationship information. The instability symptom information of the loaded object is determined based on the displacement change sequence and the failure symptom sequence; Based on the equivalent stiffness change information and the instability symptom information, the load-bearing stability index and failure mode type of the loaded object are determined; The load-bearing stability index and the failure mode type are taken as the load-bearing stability state.

[0010] Optionally, in the above scheme, predicting the loading risk within the protection window based on the actuator response characteristics and the loading status data includes: Acquire the actuator response characteristics, which include at least one of the following: load instruction response latency, fast decompression response latency, servo reverse response capability, and buffer retention capability; The duration of the protection window is determined based on the response characteristics of the actuator. Determine the current load change trend and the current displacement change trend based on the loading status data; Based on the protection window duration, the current load change trend, the current displacement change trend, and the compression energy storage state, the peak load, peak displacement, and peak energy storage within the protection window are predicted. The loading risk is obtained based on the peak load, the peak displacement, and the peak stored energy.

[0011] Optionally, in the above scheme, determining a stress-relief strategy matching the current compressive loading state when the instantaneous stress-relief triggering condition is met based on the compressed energy storage state, the load-bearing stability state, and the loading risk includes: The energy storage risk level is determined based on the compressed energy storage status. The level of instability risk is determined based on the aforementioned load-bearing stability state; The predicted over-limit risk level is determined based on the loading risk; If at least one of the energy storage risk level, the instability risk level, and the predicted over-limit risk level reaches the corresponding high-risk triggering condition, or if at least two of them reach the corresponding early warning triggering condition, it is determined that the instantaneous unloading triggering condition is met. If the instantaneous unloading trigger condition is met, an unloading strategy matching the current compressive loading state is determined based on the energy storage risk level, the instability risk level, and the predicted over-limit risk level.

[0012] Optionally, in the above scheme, determining the stress relief strategy matching the current compressive loading state based on the energy storage risk level, the instability risk level, and the predicted over-limit risk level includes: The priority for releasing compressed energy storage is determined based on the aforementioned energy storage risk level. The unloading protection mode corresponding to the loading object is determined based on the instability risk level and the load stability state. The unloading response intensity is determined based on the predicted risk level of exceeding the limit. The unloading path is determined based on the compression energy storage release priority, the unloading protection mode, and the unloading response intensity. The unloading strategy is determined based on the unloading path.

[0013] Optionally, in the above scheme, generating a controlled unloading trajectory based on the unloading strategy includes: The target residual load and target unloading duration are determined based on the unloading strategy. Determine the unloading slope constraint, rebound displacement constraint, and residual load constraint based on the unloading path; Based on the target residual load, the target unloading duration, the unloading slope constraint, the rebound displacement constraint, and the residual load constraint, a load descent trajectory is generated; The timing and amplitude of the unloading action are determined based on the load descent trajectory. The controlled unloading trajectory is obtained based on the load descent trajectory, the action timing, and the action amplitude.

[0014] Optionally, in the above scheme, the step of controlling at least two unloading actions to coordinately execute instantaneous unloading protection according to the controlled unloading trajectory, and correcting the controlled unloading trajectory and / or subsequent protection control parameters based on the unloading feedback information during the instantaneous unloading protection process, includes: Generate at least two unloading actions from the following: loading command attenuation action, rapid depressurization action, servo reverse compensation action, and buffer holding action, based on the controlled unloading trajectory; According to the action sequence and the action amplitude, control the at least two unloading actions to be executed in a coordinated manner to obtain an instantaneous unloading result; The actual load descent rate, rebound displacement, residual pressure, and actuator feedback status are collected during the instantaneous unloading protection process to obtain the unloading feedback information. Based on the deviation between the unloading feedback information and the controlled unloading trajectory, the controlled unloading trajectory is corrected; The subsequent protection control parameters are updated based on the instantaneous unloading execution result. These subsequent protection control parameters are used for instantaneous unloading triggering and controlled unloading trajectory generation during the subsequent compressive loading process.

[0015] Secondly, a pressure-resistant loading instantaneous unloading protection control system, the system comprising: The data acquisition module is used to acquire loading status data during the compression loading process; The state determination module is used to determine the compression energy storage state and the load-bearing stability state of the loading object in the current compressive loading process based on the loading state data. The risk prediction module is used to predict the loading risk within the protection window based on the response characteristics of the actuator and the loading status data. The strategy determination module is used to determine a stress relief strategy that matches the current compressive loading state when the instantaneous stress relief triggering condition is met based on the compressed energy storage state, the load-bearing stability state, and the loading risk. The trajectory generation module is used to generate a controlled unloading trajectory based on the unloading strategy. The collaborative unloading module is used to control at least two unloading actions to collaboratively perform instantaneous unloading protection according to the controlled unloading trajectory. The feedback correction module is used to correct the controlled unloading trajectory and / or subsequent protection control parameters based on the unloading feedback information during the instantaneous unloading protection process.

[0016] Compared with the prior art, this application has at least the following beneficial effects: This application, based on further analysis and research of existing technical problems, recognizes that existing technologies in the safety protection and control of compression loading equipment suffer from issues such as delayed identification of loading instability risks, difficulty in accurately controlling the compression energy release process, significant impact of actuator response delays, and the susceptibility of instantaneous unloading processes to rebound impacts. By acquiring loading state data during the compression loading process and determining the current compression energy storage state and the load-bearing stability state of the loaded object based on this data, the control process can simultaneously perceive the accumulation of compression energy in the loading system and the load-bearing instability trend of the loaded object, rather than passively protecting it solely based on whether the current load exceeds a fixed threshold. Furthermore, based on the actuator response... The characteristic and loading status data predict the loading risk within the protection window, enabling the control system to incorporate the load risk that may continue to grow during the actuator response delay into the judgment, thereby determining whether the instantaneous unloading trigger condition is met before the actual danger escalates further. When the trigger condition is met, an unloading strategy matching the current compressive loading state is determined and a controlled unloading trajectory is generated, so that the unloading process can be controlled in an orderly manner according to the current risk state, rather than simply shutting down or unrestrained depressurization. Then, at least two unloading execution actions are controlled to coordinately execute instantaneous unloading protection according to the controlled unloading trajectory, and the controlled unloading trajectory and / or subsequent protection control parameters are corrected according to the unloading feedback information, so that the unloading process can be adjusted in a closed loop during execution. Therefore, this application can reduce the impact of delayed identification of loading instability risk on safety protection, improve the controllability of the compressed energy storage release process, reduce the overshoot risk caused by the response delay of the actuator, and suppress the rebound impact that may occur during the instantaneous unloading process. This solves the problems of delayed identification of loading instability risk, difficulty in accurately controlling the compressed energy storage release process, significant impact of the response delay of the actuator, and easy rebound impact caused by the instantaneous unloading process in the safety protection control of the pressure-resistant loading equipment. Attached Figure Description

[0017] Figure 1 This is a flowchart illustrating a method for instantaneous unloading protection control under compressive loading, provided in one embodiment of this application. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0019] In one embodiment, such as Figure 1As shown, a method for instantaneous unloading protection control during compressive loading is provided. This method can be applied to hydraulic compressive loading equipment, electro-servo compressive loading equipment, pressure testing machines, component compression loading platforms, geotechnical sample loading devices, concrete component compressive testing devices, or other equipment requiring rapid and safe protection during compressive loading. The compressive loading equipment may include a loading actuator, an unloading actuator, a sensor assembly, and a controller. The controller can run an instantaneous unloading protection control program to achieve loading state identification, risk prediction, unloading strategy determination, controlled unloading trajectory generation, and unloading feedback correction.

[0020] During the compression loading process, the controller first acquires loading status data. This data can be obtained from load sensors, displacement sensors, pressure sensors, velocity detection units, servo drive feedback units, valve position feedback units, acoustic emission sensors, vibration sensors, strain sensors, etc. The loading status data can include loading force, loading displacement, loading velocity, loading acceleration, hydraulic pressure, servo motor torque, valve opening, cylinder position, vibration and impact, acoustic emission events, strain changes, and other data. The controller can acquire this data according to a preset sampling period and time-stamp data from different sources, enabling correlation analysis of data from different sensors at the same loading moment.

[0021] After obtaining the loading status data, the controller determines the compression energy storage state and the load-bearing stability state of the loaded object during the current compressive loading process. The compression energy storage state characterizes the accumulated and potentially released compressive energy in the loaded object, loading mechanism, and actuators during the compressive loading process. Specifically, the change in loading work can be determined based on the relationship between the loading force and the loading displacement, and the current compression energy storage state can be determined by combining information such as the stiffness of the loaded object, the stiffness of the loading mechanism, changes in hydraulic pressure, and the compression deformation of the actuator. The load-bearing stability state characterizes whether the loaded object is still in a stable load-bearing process and whether stiffness degradation, sudden displacement, crack propagation, local buckling, eccentric instability, or other signs of instability have occurred. Specifically, the load-bearing stability state can be determined based on information such as the load-displacement relationship, equivalent stiffness change information, displacement change trend, vibration and impact characteristics, and acoustic emission characteristics.

[0022] After determining the compressed energy storage state and the load stability state, the controller predicts the loading risk within the protection window based on the actuator response characteristics and loading state data. The actuator response characteristics characterize the response capability and response delay required for actions such as load command attenuation, rapid depressurization, servo reverse compensation, and buffer holding to truly produce the unloading effect after the controller issues a control command. The protection window can be understood as the time range from when the controller issues an instantaneous unloading protection command to when the loading force actually enters the descent process; it can also include the risk accumulation time range before the actuator completes its initial unloading response. The controller can predict the peak load, peak displacement, peak energy storage, or other loading risks that may be reached within the protection window based on the current load change trend, current displacement change trend, compressed energy storage state, and actuator response characteristics, thereby avoiding triggering protection only after actual exceedances.

[0023] When the controller determines that the instantaneous unloading trigger condition is met based on the compressed energy storage state, load stability state, and loading risk, it determines an unloading strategy that matches the current compressive loading state. The instantaneous unloading trigger condition may include one or more of the following: the compressed energy storage state reaching the energy storage risk condition, the load stability state reaching the instability risk condition, or the loading risk reaching the predicted over-limit condition. The unloading strategy is used to determine the appropriate unloading method, intensity, and path. For example, when the loaded object has a risk of brittle failure and a high compressed energy storage, a combined unloading strategy of rapid decompression and buffer retention can be used; when the energy storage on the actuator side is high, rapid decompression can be prioritized; when the energy storage on the loading mechanism side is high, servo reverse compensation can be added; when the risk of rebound displacement is high, a smaller unloading slope can be used while retaining the target residual load.

[0024] After determining the unloading strategy, the controller generates a controlled unloading trajectory based on the strategy. The controlled unloading trajectory can include the load descent trajectory, unloading slope, target residual load, target unloading duration, timing of unloading actions, and amplitude of the unloading actions. The controlled unloading trajectory does not simply reduce the applied force to zero; rather, it determines a safe and controllable unloading process based on the loading risk and the current compressive loading state, ensuring that the applied force decreases according to a set slope and target range, while limiting secondary risks such as rebound displacement, residual pressure, and vibration impact.

[0025] After generating the controlled unloading trajectory, the controller coordinates at least two unloading actions to perform instantaneous unloading protection according to the controlled unloading trajectory. Unloading actions can include load command attenuation, rapid depressurization, servo reverse compensation, buffer holding, bypass depressurization, and mechanical locking. Different unloading actions can be executed according to a preset sequence or dynamically adjusted based on real-time feedback. For example, the load command can be rapidly attenuated while simultaneously opening the rapid depressurization valve; after the load decreases to a certain range, the servo loading mechanism can be controlled to enter reverse compensation mode; when the load approaches the target residual load, it enters buffer holding mode to prevent violent rebound of the loaded object or fixture.

[0026] During the instantaneous load relief protection process, the controller corrects the controlled load relief trajectory and / or subsequent protection control parameters based on the load relief feedback information. The load relief feedback information may include the actual load descent rate, rebound displacement, residual pressure, valve position feedback, servo torque, vibration impact, and actuator response status. If the actual load descent rate is lower than the target load descent rate, the amplitude of the rapid load relief action can be increased or the servo reverse compensation amount can be increased; if the rebound displacement or vibration impact exceeds the safe range, the load relief slope can be reduced and the buffer holding time increased; if the residual pressure drop is insufficient, the rapid load relief action can be extended or the valve opening adjusted. After load relief is completed, the controller can also update the subsequent protection control parameters based on the actual load relief response time, peak load, rebound displacement, residual pressure, etc., making the triggering conditions and controlled load relief trajectory in the subsequent pressure loading process more suitable for the current equipment and the loading object.

[0027] In this embodiment, instead of simply shutting down or depressurizing based on a fixed load threshold during the compression loading process, the system comprehensively considers the compressed energy storage state, the load stability state, and the loading risk within the protection window to pre-determine the instantaneous unloading demand. It then coordinates at least two unloading actions through an unloading strategy and a controlled unloading trajectory to complete the controlled unloading. Therefore, this method reduces problems such as delayed identification of loading instability risks, delayed actuator response, uncontrollable release of compressed energy storage, and rebound impacts caused by instantaneous unloading, thereby improving the safety protection capability and unloading process stability of the compression loading equipment.

[0028] In some embodiments, when acquiring loading status data during the compressive loading process, raw loading data during the compressive loading process can be collected first. The raw loading data may include at least two of the following: loading force data, loading displacement data, loading speed data, actuator status data, and load object failure symptom data. Loading force data can be obtained by a load sensor, pressure conversion unit, or force acquisition module; loading displacement data can be obtained by a displacement sensor, grating ruler, cylinder displacement sensor, or servo drive position feedback unit; loading speed data can be calculated from displacement change or directly acquired by a speed sensor. Actuator status data may include hydraulic pressure, valve opening, valve position feedback, servo motor torque, servo motor speed, cylinder position, control command output, etc. Load object failure symptom data may include acoustic emission events, vibration impact, sudden strain changes, abnormal local displacement, crack propagation detection signals, etc.

[0029] After acquiring the raw loading data, time synchronization and validity processing can be performed on the raw loading data to obtain synchronized loading data. Time synchronization can be achieved using a unified sampling clock, timestamp alignment, interpolation alignment, or window resampling, ensuring that data from different acquisition channels correspond to the same loading time axis. Validation processing can include outlier removal, signal limiting, noise filtering, missing value compensation, duplicate data removal, and sampling delay compensation. For example, for instantaneous spike noise acquired by the load sensor, filtering can be performed based on the changing trends of adjacent sampling points; for acoustic emission or vibration impact data, the number of events, peak intensity, or energy characteristics can be extracted according to a preset time window; for actuator status data, the validity of the data can be determined based on the difference between valve position feedback and control commands.

[0030] After obtaining the synchronous loading data, a loading force change sequence, a displacement change sequence, an actuator response sequence, and a failure symptom sequence can be generated based on the synchronous loading data. The loading force change sequence describes the process of loading force changing over time and can include information such as loading force value, load growth rate, and load fluctuation. The displacement change sequence describes the process of loading displacement changing over time and can include information such as displacement value, displacement growth rate, and displacement abrupt change. The actuator response sequence describes the response process of the actuator to loading or unloading commands and can include information such as valve opening changes, cylinder pressure changes, servo torque changes, and command response delay. The failure symptom sequence describes the changes in the load object before failure during the loading process and can include information such as acoustic emission event density, vibration impact intensity, and strain abrupt change.

[0031] Finally, the loading force change sequence, displacement change sequence, actuator response sequence, and failure symptom sequence are used as loading status data. Correspondences can be established between these sequences according to time windows, so that subsequent analysis of the compressed energy storage state, load stability state, and loading risk can be conducted based on load changes, displacement changes, actuator response changes, and failure symptom changes within the same time period.

[0032] In this embodiment, the loading status data is no longer limited to a single load value or a single displacement value, but forms multi-dimensional status data that can reflect the loading process, the actuator response process, and the signs of damage to the loaded object. This provides a complete data foundation for subsequent determination of compressed energy storage status, identification of load stability status, and prediction of loading risks within the protection window, thereby improving the accuracy and timeliness of instantaneous unloading trigger judgment.

[0033] In some embodiments, when determining the compression energy storage state of the current compressive loading process based on loading state data, the loading work change information of the current compressive loading process can be determined first based on the loading force change sequence and displacement change sequence. The loading work change information is used to characterize the energy changes input by the external loading mechanism to the loading object and related mechanical structures during the loading process. Specifically, the loading work increment within a unit time period can be determined based on the loading force and displacement changes at adjacent sampling times, and the loading work change information can be accumulated in chronological order. The loading work change information may include the current cumulative loading work, the loading work growth rate, and the change in loading work per unit displacement, etc.

[0034] Subsequently, the stiffness information of the loaded object, the stiffness information of the loading mechanism, and the compression state information of the actuator are determined based on the loading state data. The stiffness information of the loaded object can be determined based on the relationship between load and displacement, such as determining the current equivalent stiffness based on the relationship between the change in loading force and the change in loading displacement, or it can be determined in conjunction with the type, size, material parameters, or historical loading curves of the loaded object. The stiffness information of the loading mechanism can be determined based on the structural stiffness parameters of the loading frame, pressure head, clamps, support structures, etc., or it can be determined based on equipment calibration data or no-load compression test data. The compression state information of the actuator can be determined based on hydraulic pressure, cylinder displacement, hydraulic fluid compressibility, servo drive position deviation, valve status, etc., and is used to characterize the state of releasable energy accumulated in the hydraulic actuator or electric servo actuator.

[0035] After obtaining information on the changes in loading work, the stiffness of the loaded object, the stiffness of the loading mechanism, and the compression state of the actuator, the energy storage states on the loaded object side, the loading mechanism side, and the actuator side can be determined. The energy storage state on the loaded object side characterizes the energy stored in the loaded object due to compression deformation, and the extent to which this energy may be released when the loaded object cracks, buckles, crushes, or becomes unstable. The energy storage state on the loading mechanism side characterizes the energy stored in the loading frame, indenter, clamps, connecting structures, etc., due to elastic deformation. The energy storage state on the actuator side characterizes the energy stored in cylinders, hydraulic fluid, accumulators, servo motor drive chains, or other loading actuators. The controller can determine the corresponding energy storage size, energy storage growth trend, and energy release risk based on the changing characteristics of different energy storage sources.

[0036] Finally, the compressed energy storage status is obtained based on the energy storage status of the loading object, the loading mechanism, and the actuator. The compressed energy storage status can include information such as total compressed energy storage, the proportion of energy storage on each side, energy storage growth rate, main energy storage sources, releaseable impact energy, and energy storage risk level. For example, a high proportion of energy storage on the actuator side indicates that the response capability of the rapid decompression channel has a significant impact on the protection effect; a high proportion of energy storage on the loading mechanism side indicates that the elastic rebound of the loading mechanism may lead to rebound impact; and a high proportion of energy storage on the loading object side with poor load-bearing stability indicates a high risk of energy release when the loading object experiences instantaneous failure.

[0037] This embodiment describes the accumulation of dangers during the compressive loading process from the perspective of energy source, avoiding the reliance solely on whether the current load exceeds the limit as the basis for protection. Since the compressive energy storage state simultaneously reflects the energy storage status of the loading object, the loading mechanism, and the actuator, a matching unloading strategy can be determined based on the risk differences of different energy storage sides, thereby improving the targeting and stability of instantaneous unloading protection.

[0038] In some embodiments, when determining the load-bearing stability state of a loaded object based on loading state data, load-displacement relationship information can be generated first based on the loading force change sequence and displacement change sequence. This load-displacement relationship information can be used to characterize the correspondence between the load-bearing capacity and deformation response of the loaded object during compressive loading. The controller can correlate the loading force and loading displacement according to a preset time window or preset displacement interval to form a continuous load-displacement curve, and can also extract features such as local slope, curve nonlinear deviation, pre-peak variation trend, and post-peak softening trend.

[0039] After generating the load-displacement relationship information, the equivalent stiffness change information can be determined based on this information. The equivalent stiffness change information can include the current equivalent stiffness, the rate of decrease in equivalent stiffness, the fluctuation in equivalent stiffness, and the abrupt change in equivalent stiffness. If the loaded object is in a stable bearing stage, the load-displacement relationship usually shows a relatively stable upward trend; if the loaded object experiences crack propagation, local crushing, internal damage, or signs of pre-buckling, the equivalent stiffness may decrease, fluctuate, or change abruptly. Therefore, the equivalent stiffness change information can serve as an important basis for judging the stability of the load-bearing state.

[0040] Simultaneously, the instability signs of the loaded object can be determined based on the displacement change sequence and the failure symptom sequence. Instability symptom information can include information on sudden displacement changes, changes in acoustic emission event density, changes in vibration and impact intensity, sudden strain changes, and multi-point displacement differences. For example, when the load increase is not significant but the displacement suddenly increases, it may indicate localized damage or abnormal contact conditions in the loaded object; when acoustic emission events occur in a concentrated manner within a short period, it may indicate rapid propagation of internal cracks; when the vibration and impact intensity suddenly increases, it may indicate that the loaded object or fixture is at risk of instantaneous impact or slippage.

[0041] Subsequently, based on the information on equivalent stiffness changes and instability symptoms, the load-bearing stability index and failure mode type of the loaded object are determined. The load-bearing stability index quantifies the risk of the currently loaded object approaching instability or failure, and can be determined comprehensively based on the degree of equivalent stiffness reduction, displacement abrupt changes, the intensity and duration of failure symptoms. The failure mode type distinguishes the possible failure modes of the loaded object, such as brittle fracture, ductile crushing, local buckling, eccentric instability, and clamp slippage. Different failure mode types correspond to different unloading requirements; for example, brittle fracture requires rapid reduction of the dangerous load, local buckling requires limiting abrupt changes in attitude, and clamp slippage requires preventing complete unloading that could lead to clamping failure.

[0042] Finally, the load stability index and failure mode type are used as the load stability state. The load stability state can be used together with the compressed energy storage state and loading risk to determine whether instantaneous unloading protection is triggered, and it can also be used for subsequent unloading strategy determination and controlled unloading trajectory generation.

[0043] This embodiment not only reflects the current load level under load stability, but also identifies precursors of failure such as changes in equivalent stiffness, sudden displacement, acoustic emission, and vibration shock. This allows the controller to identify instability risks before the loaded object is completely destroyed or the load actually exceeds its limits, and select a more suitable instantaneous unloading protection method according to different failure modes.

[0044] In some embodiments, when predicting loading risk within a protection window based on actuator response characteristics and loading status data, the actuator response characteristics can be obtained first. Actuator response characteristics may include at least one of loading command response delay, rapid depressurization response delay, servo reverse response capability, and buffer holding capability. Load command response delay characterizes the time required for the loading force to actually stop rising after the controller issues a loading command decay or stop command; rapid depressurization response delay characterizes the time required for a rapid depressurization valve or bypass depressurization channel to generate an effective depressurization flow from receiving the command; servo reverse response capability characterizes the ability of the servo loading mechanism to perform reverse displacement compensation or reverse torque output; buffer holding capability characterizes the ability of the loading device to maintain the target residual load or suppress rebound displacement during the unloading process.

[0045] After acquiring the actuator's response characteristics, the protection window duration can be determined based on these characteristics. The protection window duration can be determined based on the maximum value among multiple response delays, or it can be determined comprehensively based on the loading command response delay, rapid depressurization response delay, servo reverse response capability, and buffer holding capability. For hydraulic loading equipment, the protection window duration can be further determined by considering factors such as oil circuit volume, oil compressibility, valve diameter, and system pressure; for electro-servo loading equipment, the protection window duration can be further determined by considering factors such as servo motor inertia, drive response frequency, mechanical transmission clearance, and control cycle. The protection window duration reflects the timeframe within which the loading risk may continue to increase after the controller issues a protection command.

[0046] Subsequently, the current load change trend and the current displacement change trend are determined based on the loading status data. The current load change trend may include load growth rate, load acceleration, load fluctuation trend, etc.; the current displacement change trend may include displacement growth rate, displacement acceleration, displacement abrupt change trend, etc. The controller can determine the above trends based on the loading force change sequence and displacement change sequence within the current time window, or it can combine the equivalent stiffness change information in the load steady state to determine whether there is abnormal growth in load and displacement.

[0047] Subsequently, based on the protection window duration, current load variation trend, current displacement variation trend, and compressed energy storage state, the peak load, peak displacement, and peak energy storage within the protection window are predicted. Specifically, the controller can extrapolate the load variation results within the protection window according to the current load variation trend to obtain the peak load; extrapolate the displacement variation results within the protection window according to the current displacement variation trend to obtain the peak displacement; and determine the peak energy storage based on the predicted load, predicted displacement, and current compressed energy storage state. If the load-bearing stability of the loaded object is poor, the sensitivity of the loading risk prediction can be improved, enabling the prediction results to reflect the risk of sudden load changes or displacement jumps before instability.

[0048] Finally, the loading risk is derived based on the peak load, peak displacement, and peak stored energy. Loading risk can be expressed as a risk level, risk score, or risk category, and may include peak load exceeding risk, peak displacement exceeding risk, and peak stored energy release risk. Loading risk is used to subsequently determine whether the instantaneous unloading trigger condition is met.

[0049] In this embodiment, the controller can incorporate the response delay of the actuator into the protection judgment process. When the actual load or displacement has not yet exceeded the safety threshold, the risk can be identified in advance based on the prediction results in the protection window. This avoids delays in protection action caused by hydraulic valve opening delay, servo mechanism response lag, or mechanical transmission inertia, thereby improving the advance capability and reliability of instantaneous unloading protection.

[0050] In some embodiments, if the instantaneous unloading triggering condition is determined based on the compressed energy storage state, the load-bearing stability state, and the loading risk, an unloading strategy matching the current compressive loading state is determined. Specifically, the energy storage risk level can be determined first based on the compressed energy storage state. The energy storage risk level can be determined based on the total compressed energy storage, the proportion of energy storage on each energy storage side, the energy storage growth rate, and the releasable impact energy, etc. If any of the energy storage states on the loading object side, the loading mechanism side, or the actuator side are at a high level, the energy storage risk level can be increased.

[0051] Subsequently, the instability risk level is determined based on the load-bearing stability state. The instability risk level can be determined based on the load-bearing stability index and the failure mode type. For example, the instability risk level can be increased when there is a rapid decrease in equivalent stiffness, significant abrupt displacement changes, frequent acoustic emission events, or enhanced vibration and impact. If the failure mode type is brittle fracture or eccentric load instability, a higher instability risk level can be set. If the failure mode type is ductile crushing, the corresponding instability risk level can be set based on the displacement growth rate and residual bearing capacity.

[0052] Then, the predicted over-limit risk level is determined based on the loading risk. The predicted over-limit risk level can be determined based on the relationship between peak load, peak displacement, and peak energy storage within the protection window and the corresponding safety thresholds. If the predicted peak load will exceed the load safety threshold, or the predicted peak displacement will exceed the displacement safety threshold, or the predicted peak energy storage will exceed the controllable unloading energy threshold, the predicted over-limit risk level can be increased.

[0053] After determining the energy storage risk level, instability risk level, and predicted over-limit risk level, it can be determined whether the instantaneous stress relief triggering condition is met. Specifically, when at least one of the energy storage risk level, instability risk level, and predicted over-limit risk level reaches the corresponding high-risk triggering condition, the instantaneous stress relief triggering condition is determined to be met; or, when at least two of the above three risk levels reach the corresponding early warning triggering condition, the instantaneous stress relief triggering condition is also determined to be met. This allows for timely triggering of protection when a single risk is particularly severe, and also for early triggering of protection when multiple risks rise simultaneously but have not yet reached the high-risk threshold.

[0054] Once the instantaneous unloading trigger condition is met, an unloading strategy matching the current compressive loading state is determined based on the energy storage risk level, instability risk level, and predicted over-limit risk level. Unloading strategies may include rapid pressure relief priority strategies, buffered unloading strategies, servo reverse compensation strategies, low-load holding strategies, segmented unloading strategies, or multi-action coordinated unloading strategies. The controller can select the corresponding unloading strategy based on different risk level combinations, ensuring that the unloading process can quickly reduce the dangerous load while avoiding rebound impact or clamp loosening caused by excessively rapid unloading.

[0055] In this embodiment, the instantaneous unloading trigger condition is not a single fixed threshold, but rather a comprehensive judgment based on the compression storage state, the load stability state, and the risk of the protection window loading. This can simultaneously cover single high-risk triggering scenarios and multiple warning combination triggering scenarios. This reduces protection lag and false triggering issues, and provides an accurate basis for subsequently generating an unloading strategy that matches the current compressive loading state.

[0056] In some embodiments, when determining a stress relief strategy matching the current compressive loading state based on the energy storage risk level, instability risk level, and predicted over-limit risk level, the priority of compressed energy storage release can be determined first based on the energy storage risk level. The compressed energy storage release priority characterizes which side's compressed energy storage should be released or controlled first. For example, when the energy storage risk level corresponding to the actuator-side energy storage state is high, rapid stress relief can be determined to have a higher priority; when the energy storage risk level corresponding to the loading mechanism-side energy storage state is high, servo reverse compensation or buffer holding can be determined to have a higher priority; when the energy storage risk level corresponding to the loading object-side energy storage state is high, limiting the stress relief slope and rebound displacement can be determined to have a higher priority.

[0057] Subsequently, the unloading protection mode corresponding to the loaded object is determined based on the instability risk level and the load stability state. The unloading protection mode can be determined according to the failure mode type and the instability risk level. For example, when the loaded object has the risk of brittle fracture, a protection mode combining rapid pressure relief and residual load maintenance can be adopted; when the loaded object has the risk of ductile crushing, a segmented unloading or buffered unloading protection mode can be adopted; when the loaded object has the risk of local buckling, a unloading protection mode that limits abrupt displacement can be adopted; when the loaded object has the risk of eccentric load instability, a unloading protection mode that maintains the stability of the loading surface attitude can be adopted; when the loaded object has the risk of clamp slippage, a protection mode that maintains low load before unloading can be adopted.

[0058] Then, the unloading response intensity is determined based on the predicted over-limit risk level. The unloading response intensity can characterize the speed and amplitude of the unloading action. For example, when the predicted peak load or peak stored energy significantly exceeds the limit, the unloading response intensity can be increased to shorten the load descent time; when the predicted over-limit risk is low but there is a rebound risk, the unloading response intensity can be decreased to enhance the smoothness of the unloading process. The unloading response intensity can correspond to control parameters such as the opening degree of the rapid pressure relief valve, the attenuation rate of the loading command, the servo reverse compensation amount, and the buffer holding time.

[0059] After determining the priority of compressed energy storage release, the unloading protection mode, and the unloading response intensity, the unloading path can be determined. The unloading path characterizes the combination and execution sequence of each unloading action. For example, an unloading path can be formed by "load command attenuation, rapid depressurization, servo reverse compensation to buffer holding," or an unloading path can be formed by "load command attenuation, low load holding to segmented unloading." For different equipment structures, the unloading path can also include actions such as bypass depressurization, accumulator isolation, and mechanical buffer locking.

[0060] Finally, the unloading strategy is determined based on the unloading path. The unloading strategy may include the unloading path, action priority, unloading response intensity, protection mode, target residual load, and initial unloading parameters, and is used to generate a controlled unloading trajectory.

[0061] The unloading strategy in this embodiment can be comprehensively determined based on the release priority of compressed energy storage, the unloading protection mode of the loaded object, and the unloading response intensity corresponding to the predicted over-limit risk, instead of using a fixed depressurization or simple emergency stop method. This allows for the generation of matching unloading paths for different energy storage sources, different failure modes, and different predicted risks, improving the adaptability and safety of instantaneous unloading protection.

[0062] In some embodiments, when generating a controlled unloading trajectory based on an unloading strategy, the target residual load and target unloading duration can be determined first according to the unloading strategy. The target residual load represents the safe load level that the loaded object must maintain after instantaneous unloading. The target residual load can prevent the loaded object, clamp, or loading mechanism from rebounding, loosening, or undergoing abrupt attitude changes due to the instantaneous drop in loading force to zero. The target unloading duration represents the time range required from triggering instantaneous unloading protection to the loading force decreasing to the target residual load. The target unloading duration can be determined based on loading risk, actuator response capability, and rebound impact risk.

[0063] Subsequently, unloading slope constraints, rebound displacement constraints, and residual load constraints are determined based on the unloading path. The unloading slope constraint limits the rate of force descent, preventing insufficient protection due to excessively slow unloading or increased impact due to excessively rapid unloading. The rebound displacement constraint limits the rebound displacement of the loaded object, pressure head, clamp, or loading mechanism during the unloading process, preventing secondary impacts or clamp loosening. The residual load constraint ensures that the loaded force remains within a safe load range after unloading, neither continuing at a dangerous load level nor causing system instability due to complete unloading.

[0064] After determining the target residual load, target unloading duration, unloading slope constraint, rebound displacement constraint, and residual load constraint, a load descent trajectory can be generated. The load descent trajectory can be a continuous descent trajectory, a segmented descent trajectory, a trajectory with an initial rapid descent followed by a slower descent, or a descent trajectory with a residual load holding section. The controller can select an appropriate trajectory form based on the unloading strategy. For example, when the predicted overload risk is high and the rebound risk is low, a larger initial unloading slope can be used; when the rebound displacement risk is high, the load can enter a buffer section after decreasing to an intermediate load, and then gradually decrease to the target residual load.

[0065] Subsequently, the timing and amplitude of the unloading actions are determined based on the load descent trajectory. The timing is used to determine the start time, duration, and termination conditions of different unloading actions. The amplitude is used to determine the load command attenuation, the opening degree of the rapid pressure relief valve, the servo reverse compensation, and the buffer holding strength. For example, the load command attenuation action can be executed immediately after the instantaneous unloading protection is triggered, while the rapid pressure relief action is controlled to open at the initial opening degree; after the load decreases to the intermediate target value, the amplitude of the rapid pressure relief action is gradually reduced, and the buffer holding action is initiated; if the actual load decrease is insufficient, the amplitude of the servo reverse compensation action is increased.

[0066] Finally, based on the load descent trajectory, action timing, and action amplitude, the controlled unloading trajectory is obtained. The controlled unloading trajectory can serve as the basis for the controller to output control commands to each unloading actuator, and can also serve as the target trajectory for feedback correction during the unloading process.

[0067] In this embodiment, the controlled unloading trajectory can transform the unloading strategy into an executable load reduction process and unloading execution action control process. This makes instantaneous unloading protection no longer a simple pressure relief or emergency stop, but a safe and controllable load reduction under constraints such as target residual load, target unloading duration, unloading slope, rebound displacement, and residual load, thereby taking into account both rapid protection and impact suppression.

[0068] In some embodiments, when controlling at least two unloading actions to coordinately perform instantaneous unloading protection according to a controlled unloading trajectory, at least two unloading actions can be generated based on the controlled unloading trajectory, including a load command attenuation action, a rapid pressure relief action, a servo reverse compensation action, and a buffer holding action. The load command attenuation action may include reducing the target load value, stopping further loading, reducing the loading speed, or switching to an unloading control mode. The rapid pressure relief action may include opening a rapid pressure relief valve, a bypass valve, a proportional relief valve, or other pressure relief channels. The servo reverse compensation action may include controlling a servo motor or hydraulic servo mechanism to perform reverse displacement, reverse torque, or zero-force following. The buffer holding action may include maintaining the load force near the target residual load, or limiting rebound displacement and vibration impact during load descent.

[0069] Subsequently, at least two unloading actions are executed collaboratively according to the action sequence and amplitude to obtain the instantaneous unloading result. The action sequence and amplitude can be derived from the controlled unloading trajectory. The controller can issue corresponding control commands to each execution unit to enable multiple unloading actions to work in tandem. For example, the loading command attenuation action can be initiated before or synchronously with the rapid decompression action; the servo reverse compensation action can enhance the unloading effect when the load descent rate is insufficient; and the buffer holding action can be initiated when the load approaches the target residual load to suppress rebound. The instantaneous unloading result can include the actual load descent process, actual residual load, actual unloading response time, actual rebound displacement, and actual residual pressure.

[0070] During the instantaneous load relief protection process, the actual load descent rate, rebound displacement, residual pressure, and actuator feedback status are collected to obtain load relief feedback information. The actual load descent rate can be used to determine whether the current load relief process has reached the target load relief rate; the rebound displacement can be used to determine whether the loaded object, pressure head, clamp, or loading mechanism has experienced excessive rebound; the residual pressure can be used to determine whether there is still high pressure in the hydraulic system or actuator; the actuator feedback status can include valve position feedback, servo torque, servo position, cylinder pressure, actuator alarm status, etc.

[0071] Subsequently, the controlled unloading trajectory is corrected based on the deviation between the unloading feedback information and the controlled unloading trajectory. For example, if the actual load descent rate is less than the target descent rate corresponding to the controlled unloading trajectory, the amplitude of the rapid unloading action or the amplitude of the servo reverse compensation action can be increased; if the rebound displacement exceeds the rebound displacement constraint, the subsequent unloading slope can be reduced, the buffer holding time can be extended, or the target residual load can be increased; if the residual pressure is higher than the target range, the duration of the rapid unloading action can be extended or the opening of the unloading valve can be adjusted; if the actuator feedback status indicates that the response of a certain action is insufficient, other unloading actions can be called for compensation.

[0072] Finally, the subsequent protection and control parameters are updated based on the instantaneous unloading execution results. These parameters can be used for instantaneous unloading triggering and controlled unloading trajectory generation during subsequent compressive loading processes. These parameters may include actuator response delay parameters, energy storage risk thresholds, instability risk thresholds, predicted over-limit risk thresholds, unloading slope limit parameters, target residual load determination parameters, rebound displacement limit parameters, and unloading execution amplitude parameters. The controller can adjust these parameters based on the actual unloading response time, actual peak load, actual rebound displacement, actual residual pressure, and actuator status to adapt to different loading objects, different equipment states, and different environmental conditions.

[0073] In this embodiment, multiple unloading actions can be executed collaboratively under the constraint of a controlled unloading trajectory, avoiding insufficient response or excessive impact from a single unloading action. At the same time, during the unloading process, the controlled unloading trajectory can be corrected in real time based on the actual load descent speed, rebound displacement, residual pressure, and feedback status of the actuator. After the unloading is completed, the subsequent protection control parameters are updated, thereby improving the closed-loop control capability and continuous adaptability of the instantaneous unloading protection process.

[0074] In some embodiments, a pressure-resistant instantaneous unloading protection control system is provided. This system may include a data acquisition module, a state determination module, a risk prediction module, a strategy determination module, a trajectory generation module, a coordinated unloading module, and a feedback correction module. These modules can be implemented by a processor in the controller executing corresponding programs, or they can be implemented collaboratively by multiple control units, acquisition units, drive units, and safety protection units. The controller can communicate with the loading actuator, the unloading actuator, and the sensor assembly.

[0075] The data acquisition module is used to acquire loading status data during the compressive loading process. The data acquisition module can connect to at least one of the following: load sensor, displacement sensor, pressure sensor, velocity detection unit, valve position feedback unit, servo drive feedback unit, acoustic emission sensor, vibration sensor, and strain sensor. It performs time synchronization, validity processing, and serialization processing on the acquired data to obtain loading status data that can be used for subsequent analysis.

[0076] The state determination module is used to determine the compression energy storage state and the load-bearing stability state of the object under load during the current compressive loading process based on the loading state data. The module can determine the loading work change information based on the changes in loading force and displacement, and combine this with the stiffness of the object under load, the stiffness of the loading mechanism, and the compression state of the actuator to determine the compression energy storage state; it can also determine the load-bearing stability state based on the load-displacement relationship, equivalent stiffness change information, and instability symptom information. The compression energy storage state and the load-bearing stability state can be output to the risk prediction module and the strategy determination module.

[0077] The risk prediction module is used to predict loading risks within a protection window based on actuator response characteristics and loading status data. The module can acquire actuator response characteristics such as loading command response delay, rapid decompression response delay, servo reverse response capability, and buffer retention capability, and determine the protection window duration based on these characteristics. Then, combining the current load change trend, current displacement change trend, and compression energy storage status, it predicts the peak load, peak displacement, and peak energy storage within the protection window to obtain the loading risk.

[0078] The strategy determination module is used to determine the unloading strategy matching the current compressive loading state, based on the compressed energy storage state, load stability state, and loading risk, provided that the instantaneous unloading trigger condition is met. The strategy determination module can determine the energy storage risk level based on the compressed energy storage state, the instability risk level based on the load stability state, and the predicted over-limit risk level based on the loading risk. When the instantaneous unloading trigger condition is met, it determines the compressed energy storage release priority, unloading protection mode, unloading response intensity, and unloading path based on the aforementioned risk levels, thereby obtaining the unloading strategy.

[0079] The trajectory generation module is used to generate a controlled unloading trajectory based on the unloading strategy. The trajectory generation module can determine the target residual load and target unloading duration according to the unloading strategy, determine the unloading slope constraint, rebound displacement constraint and residual load constraint according to the unloading path, and generate the load descent trajectory; further, it determines the action sequence and action amplitude of each unloading action based on the load descent trajectory to obtain the controlled unloading trajectory.

[0080] The coordinated unloading module is used to control at least two unloading actions to coordinately perform instantaneous unloading protection according to the controlled unloading trajectory. The coordinated unloading module can be connected to a loading control unit, a fast pressure relief valve, a proportional relief valve, a bypass valve, a servo drive unit, a buffer holding unit, or a mechanical locking unit, and controls at least two of the following actions to be coordinated according to the controlled unloading trajectory: loading command attenuation action, fast pressure relief action, servo reverse compensation action, and buffer holding action.

[0081] The feedback correction module is used to correct the controlled unloading trajectory and / or subsequent protection control parameters based on the unloading feedback information during the instantaneous unloading protection process. The module can collect the actual load descent rate, rebound displacement, residual pressure, and actuator feedback status, and compare the unloading feedback information with the controlled unloading trajectory. When a deviation exists, the module can adjust the unloading slope, action sequence, action amplitude, target residual load, or buffer holding time. After unloading is completed, the module can also update subsequent protection control parameters based on the instantaneous unloading execution results.

[0082] In this embodiment, the instantaneous unloading protection control system for compressive loading can complete the acquisition of loading status, determination of compressed energy storage status and load stability status, prediction of loading risks within the protection window, determination of unloading strategy, generation of controlled unloading trajectory, coordinated unloading execution, and feedback correction, forming a closed-loop protection process from risk identification to controlled unloading and then to parameter updating. This system can reduce the safety risks of compressive loading equipment under conditions of loading instability, actuator delay, and rapid release of compressed energy storage, and improve the response speed, control accuracy, and equipment adaptability of instantaneous unloading protection.

[0083] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

Claims

1. A method for instantaneous unloading protection control under compressive loading, characterized in that, The method includes: Obtain loading status data during the stress loading process; The compression energy storage state and load-bearing stability state of the loading object are determined based on the loading state data during the current compressive loading process. Based on the response characteristics of the actuator and the loading status data, the loading risk within the protection window is predicted; If the instantaneous unloading triggering condition is met based on the compressed energy storage state, the load-bearing stability state, and the loading risk, an unloading strategy matching the current compressive loading state is determined. A controlled unloading trajectory is generated based on the unloading strategy; At least two unloading actions are controlled according to the controlled unloading trajectory to perform instantaneous unloading protection in a coordinated manner. Based on the unloading feedback information during the instantaneous unloading protection process, the controlled unloading trajectory and / or subsequent protection control parameters are corrected.

2. The instantaneous unloading protection control method for compressive loading according to claim 1, characterized in that, The acquisition of loading status data during the compression loading process includes: Collect raw loading data during the compressive loading process. The raw loading data includes at least two of the following: loading force data, loading displacement data, loading speed data, actuator status data, and load object failure signs data. The original loaded data is processed for time synchronization and validity to obtain synchronized loaded data; Generate a loading force change sequence, a displacement change sequence, an actuator response sequence, and a failure sign sequence based on the synchronous loading data; The loading force change sequence, the displacement change sequence, the actuator response sequence, and the damage sign sequence are used as the loading state data.

3. The instantaneous unloading protection control method for compressive loading according to claim 2, characterized in that, Determining the compression storage state of the current compressive loading process based on the loading state data includes: The loading work change information of the current compressive loading process is determined based on the loading force change sequence and the displacement change sequence; The stiffness information of the loaded object, the stiffness information of the loading mechanism, and the compression status information of the actuator are determined based on the loading status data. Based on the loading power change information, the loading object stiffness information, the loading mechanism stiffness information, and the actuator compression state information, determine the energy storage state on the loading object side, the energy storage state on the loading mechanism side, and the energy storage state on the actuator side. The compression energy storage state is obtained based on the energy storage state of the loading object side, the energy storage state of the loading mechanism side, and the energy storage state of the actuator side.

4. The instantaneous unloading protection control method for compressive loading according to claim 2, characterized in that, Determining the load stability state of the loaded object based on the load state data includes: Generate load-displacement relationship information based on the loading force change sequence and the displacement change sequence; The equivalent stiffness change information is determined based on the load-displacement relationship information. The instability symptom information of the loaded object is determined based on the displacement change sequence and the failure symptom sequence; Based on the equivalent stiffness change information and the instability symptom information, the load-bearing stability index and failure mode type of the loaded object are determined; The load-bearing stability index and the failure mode type are taken as the load-bearing stability state.

5. The instantaneous unloading protection control method for compressive loading according to any one of claims 1 to 4, characterized in that, The prediction of loading risks within the protection window based on the actuator response characteristics and the loading status data includes: Acquire the actuator response characteristics, which include at least one of the following: load instruction response latency, fast decompression response latency, servo reverse response capability, and buffer retention capability; The duration of the protection window is determined based on the response characteristics of the actuator. Determine the current load change trend and the current displacement change trend based on the loading status data; Based on the protection window duration, the current load change trend, the current displacement change trend, and the compressed energy storage state, the peak load, peak displacement, and peak energy storage within the protection window are predicted. The loading risk is obtained based on the peak load, the peak displacement, and the peak stored energy.

6. The instantaneous unloading protection control method for compressive loading according to claim 5, characterized in that, The step of determining a stress-relief strategy matching the current compressive loading state, based on the compressed energy storage state, the load-bearing stability state, and the loading risk, when the instantaneous stress-relief triggering condition is met, includes: The energy storage risk level is determined based on the compressed energy storage status. The level of instability risk is determined based on the aforementioned load-bearing stability state; The predicted over-limit risk level is determined based on the loading risk; If at least one of the energy storage risk level, the instability risk level, and the predicted over-limit risk level reaches the corresponding high-risk triggering condition, or if at least two of them reach the corresponding early warning triggering condition, the instantaneous unloading triggering condition is determined to be met. If the instantaneous unloading trigger condition is met, an unloading strategy matching the current compressive loading state is determined based on the energy storage risk level, the instability risk level, and the predicted over-limit risk level.

7. The instantaneous unloading protection control method for compressive loading according to claim 6, characterized in that, The step of determining a stress-relief strategy matching the current compressive loading state based on the energy storage risk level, the instability risk level, and the predicted over-limit risk level includes: The priority for releasing compressed energy storage is determined based on the aforementioned energy storage risk level. The unloading protection mode corresponding to the loading object is determined based on the instability risk level and the load stability state. The unloading response intensity is determined based on the predicted risk level of exceeding the limit. The unloading path is determined based on the compression energy storage release priority, the unloading protection mode, and the unloading response intensity. The unloading strategy is determined based on the unloading path.

8. The instantaneous unloading protection control method for compressive loading according to claim 7, characterized in that, The generation of the controlled unloading trajectory based on the unloading strategy includes: The target residual load and target unloading duration are determined based on the unloading strategy. Determine the unloading slope constraint, rebound displacement constraint, and residual load constraint based on the unloading path; Based on the target residual load, the target unloading duration, the unloading slope constraint, the rebound displacement constraint, and the residual load constraint, a load descent trajectory is generated; The timing and amplitude of the unloading action are determined based on the load descent trajectory. The controlled unloading trajectory is obtained based on the load descent trajectory, the action timing, and the action amplitude.

9. The instantaneous unloading protection control method for compressive loading according to claim 8, characterized in that, The step of controlling at least two unloading actions to coordinately execute instantaneous unloading protection according to the controlled unloading trajectory, and correcting the controlled unloading trajectory and / or subsequent protection control parameters based on unloading feedback information during the instantaneous unloading protection process, includes: Generate at least two unloading actions from the following: loading command attenuation action, rapid depressurization action, servo reverse compensation action, and buffer holding action, based on the controlled unloading trajectory; According to the action sequence and the action amplitude, control the at least two unloading actions to be executed in a coordinated manner to obtain an instantaneous unloading result; The actual load descent rate, rebound displacement, residual pressure, and actuator feedback status are collected during the instantaneous unloading protection process to obtain the unloading feedback information. Based on the deviation between the unloading feedback information and the controlled unloading trajectory, the controlled unloading trajectory is corrected; The subsequent protection control parameters are updated based on the instantaneous unloading execution result. These subsequent protection control parameters are used for instantaneous unloading triggering and controlled unloading trajectory generation during the subsequent compressive loading process.

10. A pressure-resistant instantaneous unloading protection control system, characterized in that, The system includes: The data acquisition module is used to acquire loading status data during the compression loading process; The state determination module is used to determine the compression energy storage state and the load-bearing stability state of the loading object in the current compressive loading process based on the loading state data. The risk prediction module is used to predict the loading risk within the protection window based on the response characteristics of the actuator and the loading status data. The strategy determination module is used to determine a stress relief strategy that matches the current compressive loading state when the instantaneous stress relief triggering condition is met based on the compressed energy storage state, the load-bearing stability state, and the loading risk. The trajectory generation module is used to generate a controlled unloading trajectory based on the unloading strategy. The collaborative unloading module is used to control at least two unloading actions to collaboratively perform instantaneous unloading protection according to the controlled unloading trajectory. The feedback correction module is used to correct the controlled unloading trajectory and / or subsequent protection control parameters based on the unloading feedback information during the instantaneous unloading protection process.

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