A multi-cylinder synchronous jacking control system based on displacement and pressure double feedback

Abstract

This invention relates to the field of synchronous control technology and discloses a multi-cylinder synchronous lifting control system based on dual feedback of displacement and pressure. The invention aims to solve the technical problems of low synchronization accuracy and unstable operation caused by adjustment lag in existing displacement feedback synchronous control systems. This invention collects displacement and pressure data from each lifting unit in real time, generates basic control commands for error correction based on displacement deviation, and generates pressure compensation commands for load prediction based on pressure deviation. These two commands are then superimposed into a composite control command, achieving precise control of each unit. By combining displacement feedback and pressure compensation, this invention achieves proactive response to load changes, effectively suppresses adjustment lag, and thus improves the synchronization accuracy and operational stability of the system.

Description

Technical Field

[0001] This invention relates to the field of synchronous control technology, and more specifically, to a multi-cylinder synchronous lifting control system based on dual feedback of displacement and pressure. Background Technology

[0002] In construction engineering, bridge construction, and heavy equipment installation, using multiple hydraulic cylinders as lifting support points to hoist or adjust the posture of large and heavy components is a common technique. To ensure the stability and structural safety of the components during the lifting process, it is essential to ensure that the extension displacements of all hydraulic cylinders remain highly synchronized. Currently, to achieve this, most mainstream synchronization control systems in the industry rely on real-time monitoring and feedback adjustment of the displacement of each hydraulic cylinder. The basic working principle is as follows: displacement sensors installed on each cylinder acquire its real-time displacement; the central controller compares the actual displacement of each point with a theoretical synchronization target; and based on the resulting displacement deviation, adjusts the control commands to the oil supply valves of each cylinder to correct the deviation and achieve synchronization.

[0003] However, in practical engineering applications, the weight distribution of the lifted component is often uneven, leading to significant differences in the actual load borne by each hydraulic cylinder support point. Furthermore, factors such as mechanical friction within the cylinders themselves, changes in hydraulic oil viscosity, and internal and external leaks introduce uncertain disturbances. Under these complex conditions, traditional control systems relying solely on displacement feedback exhibit an inherent technical flaw: their adjustment action is significantly lagging. The controller must wait until a visible, actual displacement deviation occurs before it can begin correction. When a lifting point slows down due to a sudden increase in load, the system cannot anticipate and proactively respond; it can only passively perform lagging compensation adjustments after detecting the deviation. This not only reduces the accuracy of synchronous control but also easily causes system oscillations through repeated overshoot and corrections, thus affecting the stability and safety of the entire lifting process. Summary of the Invention

[0004] In view of the aforementioned existing problems, the present invention is proposed.

[0005] Therefore, this invention provides a multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback, which solves the technical problems of low synchronization accuracy and unstable operation caused by the adjustment lag in the existing displacement feedback synchronous control system.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: This invention provides a multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback, which includes the following steps: The hydraulic lifting unit includes a hydraulic cylinder, an electro-hydraulic proportional valve in fluid communication with the hydraulic cylinder, a displacement sensor for measuring the displacement of the hydraulic cylinder, and a pressure sensor for measuring the internal pressure of the hydraulic cylinder. A central controller establishes communication connections with the displacement sensor, the pressure sensor, and the electro-hydraulic proportional valve, and the central controller is configured to: Real-time acquisition of actual displacement data output by all displacement sensors and actual pressure data output by all pressure sensors; The displacement deviation of the actual displacement data of each hydraulic lifting unit relative to the average displacement value of all hydraulic lifting units is calculated, and a basic control command is generated based on the displacement deviation. At the same time, the pressure deviation of the actual pressure data of each hydraulic lifting unit relative to the average pressure value of all hydraulic lifting units is calculated, and a pressure compensation command is generated based on the pressure deviation. The basic control command and the pressure compensation command used for the same hydraulic lifting unit are superimposed to form a composite control command; The composite control command is sent to the corresponding electro-hydraulic proportional valve to control the lifting speed of the hydraulic lifting unit.

[0007] As a preferred embodiment of the multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback described in this invention, the central controller is further equipped with a pre-lifting function, which includes: driving the piston rod of the hydraulic cylinder to extend while simultaneously monitoring the displacement sensor and the pressure sensor; determining the moment when the reading of the pressure sensor jumps as the value of the displacement sensor changes continuously as the contact moment between the piston rod and the lifted component; after confirming that all hydraulic lifting units are in contact with the lifted component, continuing to synchronously supply oil to all hydraulic cylinders until the readings of the pressure sensors all reach the preset initial support pressure value to establish the initial bearing state.

[0008] As a preferred embodiment of the multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback described in this invention, the central controller specifically uses a proportional-integral-derivative control algorithm to take the displacement deviation as input to generate the basic control command.

[0009] As a preferred embodiment of the multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback described in this invention, the central controller uses an internally stored pressure-flow compensation model to determine a pressure compensation command based on the pressure deviation; wherein, when the pressure deviation is positive, a compensation command to increase the oil supply flow is generated; and when the pressure deviation is negative, a compensation command to decrease the oil supply flow is generated.

[0010] As a preferred embodiment of the multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback described in this invention, the specific method of superposition is to determine the command value of the composite control command through the following logical relationship: Composite command value = α × command value of basic control command + β × command value of pressure compensation command; Where α and β are preset weighting coefficients.

[0011] As a preferred embodiment of the multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback described in this invention, the displacement sensor is a magnetostrictive displacement sensor built into the hydraulic cylinder; and the pressure sensor is installed on the pipeline between the electro-hydraulic proportional valve and the hydraulic cylinder inlet.

[0012] As a preferred embodiment of the multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback described in this invention, the electro-hydraulic proportional valve is a high-frequency response electro-hydraulic proportional servo valve with valve core position feedback.

[0013] As a preferred embodiment of the multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback described in this invention, the central controller is further configured to perform safety monitoring, specifically: continuously comparing the displacement deviation with a preset maximum synchronization error threshold, and comparing the actual pressure data with a preset maximum working pressure threshold; when a data exceeding its corresponding threshold is detected, immediately controlling all electro-hydraulic proportional valves to close, so as to lock all hydraulic lifting units in the current position.

[0014] As a preferred embodiment of the multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback described in this invention, the central controller calculates the average displacement value by acquiring all actual displacement data at the same acquisition time and calculating the arithmetic mean of these data.

[0015] As a preferred embodiment of the multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback described in this invention, the central controller calculates the average pressure value by acquiring all actual pressure data at the same acquisition time and calculating the arithmetic mean of these data.

[0016] The beneficial effects of this invention are as follows: By introducing pressure feedback as a feedforward compensation signal, this invention enables the control system to quantify and predict disturbances caused by unbalanced loads at each lifting point in real time, thereby allowing for proactive, feedforward adjustments before visible displacement deviations occur. This design overcomes the inherent lag of existing single-position feedback control systems, which must wait for errors to occur before corrections can be made. Furthermore, this invention superimposes displacement feedback commands for precise error correction with pressure feedback commands for predictive compensation, forming a composite control command that combines the advantages of both adjustment methods. This not only allows for a faster response to load changes but also effectively suppresses overshoot and oscillations during the control process, ultimately significantly improving the synchronization accuracy and operational stability of multi-cylinder synchronous lifting operations under complex conditions. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the following description of the embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall workflow of a multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback.

[0019] Figure 2 This is a schematic diagram of the main synchronous lifting control cycle process according to an embodiment of the present invention.

[0020] Figure 3 This is a detailed flowchart illustrating the pre-lifting function according to an embodiment of the present invention.

[0021] Figure 4 This is a schematic diagram of the weighted superposition and dynamic adjustment strategy process according to an embodiment of the present invention. Detailed Implementation

[0022] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0023] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0024] Secondly, the term "one embodiment" or "example" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the invention. The appearance of an embodiment in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that mutually excludes other embodiments.

[0025] Example 1 Reference Figures 1-3 This is the first embodiment of the present invention, which provides a multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback, comprising: The hydraulic lifting unit includes a hydraulic cylinder, an electro-hydraulic proportional valve in fluid communication with the hydraulic cylinder, a displacement sensor for measuring the displacement of the hydraulic cylinder, and a pressure sensor for measuring the internal pressure of the hydraulic cylinder. The central controller establishes communication connections with the displacement sensor, pressure sensor, and electro-hydraulic proportional valve, and is configured as follows: Real-time acquisition of actual displacement data output by all displacement sensors and actual pressure data output by all pressure sensors; The displacement deviation of the actual displacement data of each hydraulic lifting unit relative to the average displacement value of all hydraulic lifting units is calculated, and basic control commands are generated based on the displacement deviation. At the same time, the pressure deviation of the actual pressure data of each hydraulic lifting unit relative to the average pressure value of all hydraulic lifting units is calculated, and pressure compensation commands are generated based on the pressure deviation. The basic control commands and pressure compensation commands used for the same hydraulic lifting unit are superimposed to form composite control commands; The composite control command is sent to the corresponding electro-hydraulic proportional valve to control the lifting speed of the hydraulic jacking unit.

[0026] The central controller is also equipped with a pre-lifting function, which includes: extending the piston rod of the hydraulic cylinder while simultaneously monitoring the displacement and pressure sensors; detecting a jump in the pressure sensor reading as the displacement sensor reading changes continuously, identifying the moment when the piston rod contacts the lifted component; and after confirming that all hydraulic lifting units are in contact with the lifted component, continuing to supply oil to all hydraulic cylinders synchronously until the pressure sensor readings all reach the preset initial support pressure value to establish the initial load-bearing state.

[0027] The displacement sensor is a magnetostrictive displacement sensor built into the hydraulic cylinder; and the pressure sensor is installed on the pipeline between the electro-hydraulic proportional valve and the hydraulic cylinder inlet.

[0028] The electro-hydraulic proportional valve is a high-frequency response electro-hydraulic proportional servo valve with valve core position feedback.

[0029] The central controller uses an internally stored pressure-flow compensation model to determine the pressure compensation command based on the pressure deviation. Specifically, when the pressure deviation is positive, a compensation command to increase the oil supply flow is generated; when the pressure deviation is negative, a compensation command to decrease the oil supply flow is generated.

[0030] The central controller is also configured to perform safety monitoring, specifically by continuously comparing the displacement deviation with a preset maximum synchronization error threshold and comparing the actual pressure data with a preset maximum working pressure threshold; when any data is detected to exceed its corresponding threshold, it immediately controls all electro-hydraulic proportional valves to close, thereby locking all hydraulic lifting units in their current positions.

[0031] The central controller calculates the average displacement value by acquiring all actual displacement data at the same acquisition time and calculating the arithmetic mean of these data.

[0032] The central controller calculates the average pressure value by acquiring all actual pressure data at the same acquisition time and calculating the arithmetic mean of these data.

[0033] This embodiment uses a system containing four hydraulic lifting units as an example for illustration. These four hydraulic lifting units are labeled as hydraulic lifting units 1#, 2#, 3# and 4#, respectively.

[0034] The hydraulic cylinder is the direct actuator that provides lifting force; the displacement sensor is used to accurately measure the extension length of the piston rod of the hydraulic cylinder, i.e., the displacement; the pressure sensor is used to monitor the hydraulic oil pressure in the working chamber of the hydraulic cylinder in real time; the electro-hydraulic proportional valve is an electro-hydraulic valve that receives electrical signals from the central controller and controls the flow of hydraulic oil to its corresponding hydraulic cylinder proportionally according to the magnitude of the signal, thereby controlling the movement speed of the cylinder.

[0035] The central controller can be a high-performance programmable logic controller (PLC) or an industrial control computer (IPC). This central controller establishes reliable communication connections via cables or an industrial bus with the displacement sensors, pressure sensors, and electro-hydraulic proportional valves of all four hydraulic jacking units. This connection enables the central controller to read feedback data from all sensors in real time without delay and to independently and accurately send control commands to each electro-hydraulic proportional valve.

[0036] After the operator sets the total lifting target height, desired lifting speed, and various safety thresholds for this operation through the human-machine interface, the central controller begins to execute its core control program.

[0037] First, the system does not immediately enter the high-speed synchronous lifting state. Instead, it first performs a pre-lifting function to eliminate uncertainties caused by installation and environmental factors, establishing a baseline for subsequent high-precision synchronous control. During this stage, the central controller sends a small, unified opening command to the four electro-hydraulic proportional valves, causing a very small flow of hydraulic oil to slowly enter each hydraulic cylinder. Throughout this process, the central controller continuously monitors the readings of all displacement and pressure sensors at a very high frequency. The controller clearly observes that all displacement sensor values ​​increase steadily and continuously from zero, while all pressure sensor values ​​remain at a very low, stable level, barely enough to overcome the internal friction of the system. When the central controller detects a clear, sudden increase in the pressure sensor reading of a hydraulic lifting unit, such as unit #3, after a long period of low stability, the controller immediately determines that the piston rod of cylinder #3 has effectively contacted the bottom of the lifted component. At this point, the controller immediately adjusts the command to the electro-hydraulic proportional valve of unit #3, reducing its oil supply flow to an extremely low value that can only maintain the contact pressure, to prevent it from generating excessive lifting force on its own. The controller continues in the same manner, waiting and confirming that units #1, #2, and #4 have also made contact. After finally confirming that all hydraulic lifting units have firmly contacted the lifted component, the pre-lifting function enters its final step. The controller again synchronously supplies oil to all cylinders at an extremely low flow rate and continuously monitors the pressure readings until all pressure sensor readings stably reach a preset initial support pressure value, such as 0.5 MPa. At this point, the entire system has fully entered an initial bearing state where all gaps have been eliminated and all lifting points are evenly stressed; the pre-lifting stage is complete.

[0038] After all hydraulic lifting units have established a stable initial load state, the central controller seamlessly switches to the main synchronous lifting control mode and executes the core control algorithm cyclically with an extremely short control cycle (e.g., 10 milliseconds). To clearly illustrate the execution process of this algorithm, the following will use any control cycle (time) during the lifting process as an example. Let's take an example to illustrate.

[0039] At time t, the central controller first acquires the output data of all sensors in real time. Assume that at this time, the controller acquires the actual displacement data ( ) and actual pressure data ( )as follows: Unit 1#: , Unit 2# , Unit 3: , Unit 4: .

[0040] After acquiring the data, the central controller immediately calculates the deviation and generates dual instructions. The central controller then performs two parallel calculations internally: The first calculation addresses displacement deviation. The controller first calculates the average displacement value of all current hydraulic lifting units (…). ): , Subsequently, the controller calculates the displacement deviation of each hydraulic lifting unit. This refers to the difference between the actual displacement and the average displacement. Taking unit #3 as an example: , this The deviation clearly indicates that the lifting height of unit #3 is lagging behind the overall average level at the current moment. Based on this displacement deviation ( The central controller generates a basic control command to correct this deviation. The purpose of this command is to increase the lifting speed of Unit 3 to catch up with the average displacement.

[0041] Simultaneously, a second calculation is performed to assess the pressure deviation. At the same time, the controller calculates the average pressure value of all current hydraulic lifting units (…). ): , Subsequently, the controller calculates the pressure deviation (ΔP) of each hydraulic lifting unit, which is the difference between its actual pressure and the average pressure value. Taking unit #3 as an example again: , this The deviation clearly indicates that the load borne by unit #3 is much higher than the average level of other units, suggesting that it will continue to slow down due to excessive resistance in its subsequent movement. Based on this pressure deviation ( The central controller generates a pressure compensation command for predictive compensation. The purpose of this command is to increase the oil supply to Unit 3 in advance to help it overcome additional load resistance.

[0042] Next, the central controller superimposes the basic control commands and pressure compensation commands generated for the same hydraulic jacking unit (unit #3 in this embodiment) into a unified composite control command. Through this superposition, the composite control command has the dual function of correcting displacement deviation and compensating for load, thereby enabling more effective acceleration of the hydraulic jacking unit.

[0043] Finally, at the end of this control cycle, the central controller precisely sends the composite control command generated for Unit #3 as an electrical signal to the corresponding electro-hydraulic proportional valve of the #3 hydraulic jacking unit to adjust its movement speed. For other units, such as Unit #2 with its displacement ahead, the controller calculates and sends a composite control command that ultimately results in a "flow reduction" effect in the exact same way. At this point, a complete control cycle ends, and the system immediately enters the next cycle, continuously repeating the above process until the jacking operation is completed.

[0044] By continuously repeating the closed-loop process of acquisition, calculation, superposition, and transmission in each control cycle, this system can dynamically and in real time adjust the lifting speed of each hydraulic lifting unit, ensuring that all units remain highly synchronized throughout the entire lifting process.

[0045] Example 2 Reference Figure 4 This is a second embodiment of the present invention, which provides a multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback, comprising: The central controller uses a proportional-integral-derivative control algorithm to take the displacement deviation as input to generate basic control commands.

[0046] The specific method of superposition is to determine the instruction value of the composite control instruction through the following logical relationship: Composite instruction value = ×Instruction value of basic control instructions+ × The command value of the pressure compensation command; in, and These are the preset weighting coefficients.

[0047] The main difference between this embodiment and Embodiment 1 lies in the different implementation methods of the control algorithm executed internally by the central controller. In this embodiment, the central controller generates basic control instructions and pressure compensation instructions in each control cycle, and superimposes them to form composite control instructions. The following variant design is implemented at the algorithm level: First, in the step of generating basic control commands based on displacement deviation, this embodiment no longer uses the complete PID control algorithm containing proportional, integral, and derivative components as in Embodiment 1. Instead, it employs a simpler proportional (P) control algorithm. Specifically, the command value corresponding to the basic control command can be determined through the following logical relationship: Basic command value = × Displacement deviation; in, The proportional coefficient is preset. The advantage of this method lies in its very simple algorithm logic, minimal computational resource consumption of the central controller, and fast response speed. Although single proportional control may suffer from steady-state error in traditional applications due to its inability to completely eliminate persistent external disturbances, this potential deficiency is effectively compensated for in the dual-feedback composite control architecture of this invention. This is because the pressure compensation command in this invention can proactively and predictively counteract the effects of unbalanced loads (a typical persistent external disturbance), thereby assisting the basic control command. This allows the entire system to achieve extremely high synchronous control accuracy even with a simple proportional control algorithm.

[0048] Secondly, in the step of superimposing the basic control command and the pressure compensation command, this embodiment employs a more refined weighted superposition method instead of the simple algebraic summation in Embodiment 1. Under this method, the command value corresponding to the final composite control command can be determined through the following logical relationship: Composite instruction value = ×Base instruction value+ × Pressure compensation command value; in, and These are the weighting coefficients for the basic control commands and the pressure compensation commands, respectively. Furthermore, these two weighting coefficients... and The control strategy is not fixed throughout the lifting process; instead, it is dynamically adjusted by the central controller according to different stages of the lifting operation to optimize the control strategy. For example, in a typical dynamic adjustment strategy, the core idea is to adjust the relative importance of two commands based on the control objectives at different stages: During the initial and intermediate stages of the lifting operation, when the lifted component has just left the ground, the system stability is poor and the load distribution may change drastically. At this time, the focus of control is on quickly responding to load changes to suppress oscillations; therefore, it is necessary to increase the weight of pressure compensation commands in the final decision-making process. This is achieved by setting a value greater than... Weighting coefficients To achieve, that is, to satisfy The relationship. As a specific, non-limiting example, it can be set as follows: It is 0.4. It is 0.6; When the lifting process enters its final stage or precise positioning is required, the system has stabilized. The primary task is to accurately reach the preset target height. At this point, the control focus shifts to prioritizing the elimination of residual displacement deviations. Therefore, it is necessary to increase the weight of displacement feedback control commands in the decision-making process. This is achieved by setting a value greater than [a certain value]. Weighting coefficients To achieve, that is, to satisfy The relationship. As a specific, non-limiting example, it can be set as follows: It is 0.8. It is 0.2.

[0049] Furthermore, in certain special application conditions, such as when the lifted component is an asymmetrical structure with highly irregular geometry or weight distribution, this embodiment can optimize the calculation method of the average value. In this case, when calculating the average displacement and average pressure values ​​as theoretical synchronization benchmarks, the simple arithmetic average method in Embodiment 1 can be replaced by a weighted average method that better reflects the actual physical characteristics of the component. For example, if it is known that among the four lifting points, lifting points 1# and 3# are the main load-bearing areas and key points for attitude control, the following calculation logic can be used when calculating the average displacement value: Average displacement value ; in, , , , These are preset weighting coefficients for each lifting unit. For example, they can be set... , ,and , The theoretical synchronization reference calculated in this way will no longer be a simple geometric center, but a center of gravity or rotation that is closer to the desired motion center of the component, thus enabling more advanced and adaptive synchronization control.

[0050] Example 3 This embodiment provides a specific application implementation of a multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback. This embodiment takes a specific engineering application scenario, "synchronous lifting during bottom replacement or basic maintenance of a large thin-walled storage tank," as an example for illustration.

[0051] In this application scenario, cost control is a stringent requirement, while the stability and safety of the lifting process, especially the avoidance of structural impact, are extremely important. Therefore, this embodiment has made adaptive adjustments to the hardware configuration and safety control strategies compared to Embodiments 1 and 2.

[0052] Firstly, regarding the variation in hardware configuration, the displacement sensor used in the hydraulic jacking unit of this embodiment is no longer a magnetostrictive displacement sensor built into the hydraulic cylinder, but rather an externally mounted wire-type displacement sensor. Specifically, the main body of each wire-type displacement sensor is fixed to a stable surface at the jacking site, and the top of its retractable steel wire is reliably fixed to the bottom of the jacked tank near its corresponding hydraulic jacking unit support point via a dedicated connector. When the hydraulic cylinder lifts the tank, the steel wire is pulled out accordingly, and the measuring mechanism inside the sensor can accurately measure the extension length of the wire, thereby obtaining the actual displacement data of the jacking point. Although the absolute measurement accuracy and response frequency of the wire-type displacement sensor may be slightly lower than those of the magnetostrictive displacement sensor, it is less expensive, easier to install and maintain, and its accuracy is sufficient for most industrial jacking applications. This embodiment demonstrates that even with this different and more cost-effective displacement measurement scheme, the core dual-feedback composite control algorithm of this invention can still operate effectively.

[0053] Secondly, regarding variations in safety control strategies, this embodiment adaptively optimizes the protective actions in the system's safety monitoring function, taking into account the relatively weak rigidity and impact sensitivity of large, thin-walled storage tank structures. In this scenario, a more stringent and conservative safety threshold is typically set. For example, the maximum permissible synchronization error threshold might be set at a smaller value, such as 3 mm; while the maximum permissible working pressure threshold might be set at a relatively lower level, such as only 70% of the cylinder's rated pressure, to allow for a larger safety margin.

[0054] In this embodiment, when the central controller detects that the displacement deviation or actual pressure data of any lifting unit exceeds its preset safety threshold, its highest priority safety protection action is no longer the "immediate locking" in Embodiment 1, but switches to a "controlled synchronous slow descent" mode. In this mode, the central controller immediately calculates a control command that causes all hydraulic cylinders to descend at a preset, extremely slow, and completely synchronized speed (e.g., 0.1 mm / s) and sends it to all electro-hydraulic proportional valves. In this way, the lifted tank can be smoothly and safely lowered back to its initial support surface or safety support block while ensuring the synchronization of the attitude of all lifting points, thereby effectively avoiding secondary damage to the tank structure itself caused by the inertial impact force generated by sudden locking.

[0055] Finally, since this embodiment uses a wire-type displacement sensor with a potentially slightly lower response frequency, the control cycle of the central controller can be appropriately relaxed to match the hardware characteristics. For example, the 10-millisecond control cycle in Embodiment 1 can be adjusted to 20 milliseconds or 50 milliseconds. This further demonstrates that the control algorithm of this invention is not rigid but can be flexibly adapted to the actual hardware configuration, reasonably optimizing the demand for controller computing resources while ensuring stability and reliability.

[0056] In summary, this embodiment demonstrates an alternative implementation of the core technical solution of this invention by introducing specific variations in displacement sensor selection, safety protection strategies, and control parameters. This reflects the good engineering adaptability of the dual-feedback composite control concept proposed in this invention, which can still achieve safe and reliable synchronous lifting control when combined with different hardware conditions and engineering application requirements.

[0057] In summary, this invention introduces pressure feedback as a feedforward compensation signal, enabling the control system to quantify and predict disturbances caused by unbalanced loads at each lifting point in real time. This allows for proactive, feedforward adjustments before visible displacement deviations occur. This design overcomes the inherent lag of existing single-position feedback control systems, which must wait for errors to occur before corrections can be made. Furthermore, this invention superimposes displacement feedback commands for precise error correction with pressure feedback commands for predictive compensation. The resulting composite control command combines the advantages of both adjustment methods, enabling a faster response to load changes and effectively suppressing overshoot and oscillations during control. Ultimately, this significantly improves the synchronization accuracy and operational stability of multi-cylinder synchronous lifting operations under complex conditions.

[0058] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback, characterized in that, include: The hydraulic lifting unit includes a hydraulic cylinder, an electro-hydraulic proportional valve in fluid communication with the hydraulic cylinder, a displacement sensor for measuring the displacement of the hydraulic cylinder, and a pressure sensor for measuring the internal pressure of the hydraulic cylinder. A central controller establishes communication connections with the displacement sensor, the pressure sensor, and the electro-hydraulic proportional valve, and the central controller is configured to: Real-time acquisition of actual displacement data output by all displacement sensors and actual pressure data output by all pressure sensors; The displacement deviation of the actual displacement data of each hydraulic lifting unit relative to the average displacement value of all hydraulic lifting units is calculated, and a basic control command is generated based on the displacement deviation. At the same time, the pressure deviation of the actual pressure data of each hydraulic lifting unit relative to the average pressure value of all hydraulic lifting units is calculated, and a pressure compensation command is generated based on the pressure deviation. The basic control command and the pressure compensation command used for the same hydraulic lifting unit are superimposed to form a composite control command; The composite control command is sent to the corresponding electro-hydraulic proportional valve to control the lifting speed of the hydraulic lifting unit.

2. The multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback according to claim 1, characterized in that, The central controller is also equipped with a pre-lifting function, which includes: driving the piston rod of the hydraulic cylinder to extend while simultaneously monitoring the displacement sensor and the pressure sensor; determining the moment when the reading of the pressure sensor jumps as the value of the displacement sensor changes continuously as the moment when the piston rod contacts the lifted component; and continuing to supply oil to all hydraulic cylinders synchronously after confirming that all hydraulic lifting units are in contact with the lifted component, until the readings of the pressure sensors all reach the preset initial support pressure value to establish the initial load-bearing state.

3. The multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback according to claim 1, characterized in that, The central controller specifically uses a proportional-integral-derivative control algorithm to take the displacement deviation as input to generate the basic control command.

4. The multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback according to claim 1, characterized in that, The central controller uses an internally stored pressure-flow compensation model to determine a pressure compensation command based on the pressure deviation. When the pressure deviation is positive, a compensation command to increase the oil supply flow is generated; when the pressure deviation is negative, a compensation command to decrease the oil supply flow is generated.

5. The multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback according to claim 1, characterized in that, The specific method of superposition is to determine the instruction value of the composite control instruction through the following logical relationship: Composite command value = α × command value of basic control command + β × command value of pressure compensation command; Where α and β are preset weighting coefficients.

6. The multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback according to claim 1, characterized in that, The displacement sensor is a magnetostrictive displacement sensor built into the hydraulic cylinder; and the pressure sensor is installed on the pipeline between the electro-hydraulic proportional valve and the oil inlet of the hydraulic cylinder.

7. The multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback according to claim 6, characterized in that, The electro-hydraulic proportional valve is a high-frequency response electro-hydraulic proportional servo valve with valve core position feedback.

8. The multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback according to claim 1, characterized in that, The central controller is also configured to perform safety monitoring, specifically: continuously comparing the displacement deviation with a preset maximum synchronization error threshold and comparing the actual pressure data with a preset maximum working pressure threshold; when a data exceeds its corresponding threshold, immediately controlling all electro-hydraulic proportional valves to close, so as to lock all hydraulic lifting units in the current position.

9. The multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback according to claim 1, characterized in that, The central controller calculates the average displacement value by acquiring all actual displacement data at the same acquisition time and calculating the arithmetic mean of these data.

10. The multi-cylinder synchronous lifting control system based on displacement and pressure dual feedback according to claim 1, characterized in that, The central controller calculates the average pressure value by acquiring all actual pressure data at the same acquisition time and calculating the arithmetic mean of these data.

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