Self-balancing gravity inertia servo oil cylinder system and control method

Abstract

The application discloses a servo oil cylinder system capable of self-balancing gravity inertia and a control method, and relates to the technical field of mechanical testing equipment.The servo oil cylinder system comprises an actuating oil cylinder, a balance cylinder body, a valve block seat, a piston rod and a displacement sensor; the actuating cylinder body and the balance cylinder body are sequentially sealed and fixed in the axial direction from top to bottom to form a combined balance cylinder body; a central cavity is arranged in the actuating cylinder body in the axial direction; the lower end of the central cavity is fixedly arranged with a lower guide sleeve, and the upper end of the central cavity is fixedly arranged with an upper guide sleeve; the piston rod penetrates through the upper guide sleeve and the lower guide sleeve and is in static pressure supporting cooperation with the upper guide sleeve and the lower guide sleeve; the valve block seat is fixedly connected with the bottom of the combined balance cylinder body and is provided with an input and output valve block mounting position, a balance cylinder accumulator valve block mounting position and a balance servo valve block mounting position; and the application greatly improves the operation precision and the running stability of the equipment.

Description

Technical Field

[0001] This invention relates to the field of mechanical testing equipment technology, and in particular to a servo hydraulic cylinder system and control method capable of self-balancing gravitational inertia. Background Technology

[0002] In dynamic tests involving road spectrum and working condition spectrum reproduction, servo cylinders typically need to drive heavily loaded test objects through long-duration, high-frequency, and high-speed reciprocating motions to reproduce actual road excitations, vibration loads, and complex working conditions. For test objects such as rail transit vehicles, bogies, heavy-duty trucks, and construction machinery, their large mass, high inertia, and high frequency response requirements, coupled with the need to consider multiple evaluation objectives such as abnormal noise, comfort, and system reliability during testing, place higher demands on the high-frequency response capability, displacement control accuracy, force control stability, and clamping safety of the cylinder system.

[0003] In existing technologies, common solutions often employ conventional servo cylinders combined with hydraulic circuits consisting of balance valves, throttle valves, or accumulators. In low-frequency, low-speed, or medium-load scenarios, these solutions can achieve basic reciprocating motion and speed limiting functions. However, in high-frequency, high-load dynamic testing scenarios, the piston rod and the tested object assembly generate significant inertial forces and inertial effects during frequent reversing and high-speed reciprocating motions. Traditional fixed-damping or passive-balancing solutions struggle to dynamically compensate for this inertial effect in a timely and continuous manner, easily leading to increased position tracking deviations, significant pressure fluctuations, enhanced reversing impacts, and decreased high-frequency response.

[0004] Specifically, this is reflected in: First, the specifications of the tested samples are not fixed and their weight varies greatly. In dynamic mechanical testing, it is necessary to frequently change the test workpieces of different specifications. The mass of the tested samples varies randomly within a large range. The change in load mass directly changes the equivalent inertia of the hydraulic system, causing the system's natural frequency to drift. The throttling damping parameters of the balance valve, which are based on the fixed load matching design, cannot adapt to the weight changes. It is difficult to maintain a stable frequency response and acceleration output accuracy across the entire load range, resulting in poor consistency of test data.

[0005] Second, the test requires the hydraulic cylinder to drive the test sample to achieve high-frequency, high-speed reciprocating motion in the vertical direction, with the test excitation frequency reaching up to several hundred hertz. Under high-frequency dynamic excitation conditions, the self-weight of the test sample, piston rod, and auxiliary connecting structures will generate a large alternating inertial force with acceleration and deceleration. Traditional balance valves rely on a fixed throttling opening to form a constant back pressure, which cannot dynamically compensate for hydraulic damping in real time with the instantaneous inertial force. The inertial force will continuously interfere with the acceleration and deceleration control accuracy of the hydraulic cylinder, limiting the system's ultimate output acceleration and operating bandwidth. As can be seen from the equipment performance curve, such as... Figures 17-20 As shown, Figure 17The graph shows the sample weight versus inertial force (linear relationship). The red dashed line in the graph is the 50kN rated excitation force boundary line, and the red area above the curve is the prohibited range beyond the rated force. Constrained by the rated output force of 50kN, the maximum allowable acceleration of the system decreases logarithmically after the load increases. Heavy samples are very likely to exceed the rated output range of the hydraulic system instantaneously. Combined with the performance boundary curves corresponding to different frequencies and loads, the load and frequency increase synchronously compress the output capacity of the system, forcing a narrowing of the test condition range.

[0006] Third, there are safety hazards when the equipment is shut down, powered off, or the test is abruptly stopped. After the hydraulic power source is shut down, the system loses its active pressure supply. Traditional balance valves rely solely on fixed mechanical throttling to limit the falling speed, and cannot provide graded buffering braking. On the one hand, the test sample is prone to falling at high speed under its own weight and inertia, and the piston rod will quickly impact the cylinder end cover, causing fatigue damage to the cylinder seals and end cover structure, and shortening the service life of hydraulic components. On the other hand, in four-column and eight-column multi-axis synchronous lifting test systems, the throttling dispersion error of the balance valves of each independent cylinder cannot be synchronously corrected. After power failure and pressure loss, the falling rate of each branch cylinder is inconsistent. The tested vehicle or large component is easily overturned or damaged due to the height difference, bringing significant test safety risks.

[0007] In summary, existing conventional lifting hydraulic structures with balance valves cannot simultaneously meet the triple requirements of variable load adaptation, dynamic suppression of high-frequency inertial forces, and graded safety braking in the event of power failure. This limits the load adaptability and extreme dynamic performance of lifting dynamic mechanical testing equipment. Therefore, there is an urgent need to develop a lifting dynamic mechanical testing hydraulic control system that can adapt to variable loads and high-frequency dynamic working conditions. Summary of the Invention

[0008] To address the above problems, this invention provides a servo cylinder system and control method that can effectively ensure the stability of rapid up-and-down movement of a loaded actuated cylinder, and can achieve stepless and smooth pressure relief from high pressure to low pressure and then to zero under shutdown or sudden working conditions, ensuring safe and reliable overall operation.

[0009] The technical solution of this invention is: A self-balancing servo cylinder system, comprising: The actuating cylinder includes an actuating cylinder body, a balance cylinder body, a valve block seat, a piston rod, and a displacement sensor; The actuating cylinder and the balancing cylinder are sequentially sealed and fixedly connected from top to bottom along the axial direction to form a combined balancing cylinder; a central cavity is provided through the actuating cylinder along the axial direction, and a lower guide sleeve is fixedly assembled at the lower end of the central cavity and an upper guide sleeve is fixedly assembled at the upper end. The piston rod passes through the upper guide sleeve and the lower guide sleeve, and a hydrostatic support structure is adopted between the piston rod and the upper guide sleeve and the lower guide sleeve. The valve block seat is fixedly connected to the bottom of the combined balance cylinder body, and is provided with an input / output valve block mounting position, a balance cylinder accumulator valve block mounting position, and a balance servo valve block mounting position; The piston portion of the piston rod slides between the lower guide sleeve and the upper guide sleeve, and the axial travel displacement of the piston rod is monitored by a displacement sensor. The actuation servo valve block integrates an upper chamber pressure sensor, a lower chamber pressure sensor, and an actuation servo valve. The upper chamber pressure sensor detects the hydraulic pressure in the upper chamber of the actuation cylinder during the piston rod's descent. The lower chamber pressure sensor detects the hydraulic pressure in the lower chamber of the actuation cylinder during the piston rod's ascent. Each main oil port of the actuation servo valve is connected to the main circuit, main return oil channel, and corresponding oil port of the actuation cylinder of the actuation servo valve block. Furthermore, its pilot external oil supply port X and pilot external oil discharge port Y are respectively connected to the external supply accumulator and the external discharge accumulator. The input and output valve block has an independent high-pressure oil supply channel and a low-pressure oil return channel inside; the high-pressure oil supply channel is equipped with an input proportional pressure reducing valve and an output shut-off solenoid valve; the output shut-off solenoid valve is located between the input proportional pressure reducing valve and the oil supply interface of the actuation servo valve. The balance cylinder accumulator valve block is equipped with a balance chamber overflow valve, a balance chamber output pressure sensor, an accumulator charging and discharging oil control assembly, a balance chamber drain port accumulator, and a lifting actuation pilot oil supply pressure reducing valve. The balance chamber overflow valve is integrated into the bypass position of the main pressure flow channel of the balance chamber. Its inlet is connected to the high-pressure oil passage of the balance chamber, and its outlet is connected to the main oil drain flow channel inside the valve block. The balance chamber output pressure sensor is installed at the main oil circuit detection port of the balance chamber pressure output. The accumulator charging and discharging control assembly includes a discharge throttle valve, an accumulator discharge valve, and an accumulator replenishment valve connected in series on the accumulator charging and discharging flow channel of the balance chamber; the balance chamber accumulator is installed in the main working oil circuit of the balance chamber and is directly connected to the working chamber of the balance chamber servo valve. The accumulator for the oil drain port of the balance chamber is integrated into the low-pressure oil drain channel port of the valve block of the balance cylinder accumulator and connected in parallel in the system oil drain circuit; The actuation pilot oil supply pressure reducing valve is integrated into the pilot oil supply circuit of the balance cylinder accumulator valve block. The balance servo valve block has an internal main oil supply channel that is sequentially connected to a high-pressure filter, a balance chamber pressure reducing valve, and a balance chamber servo valve. The inlet side of the balance chamber pressure reducing valve is connected to the balance chamber input pressure sensor and the balance chamber input accumulator through the internal flow channel of the balance servo valve block, forming an integrated balance hydraulic oil supply circuit.

[0010] Specifically, the actuating cylinder body is provided with an oil port A and an oil port B that communicate with the sliding cavity of the actuating cylinder; oil enters through the oil port A, pushing the piston of the piston rod to move towards the oil port B; oil enters through the oil port B, pushing the piston of the piston rod to move towards the oil port A. The balance cylinder is provided with an R-port that communicates with the inner cavity. The return oil is throttled through the R-port to form a stable back pressure, which generates an upward hydraulic support force on the piston rod, thus achieving a smooth and rapid descent.

[0011] Specifically, the top of the piston rod extends from the top opening of the inner cavity of the actuating cylinder and is provided with an anti-rotation plate; the anti-rotation plate is provided with a lifting pin.

[0012] Specifically, the actuation servo valve block is connected to the side of the actuation cylinder; the actuation servo valve block is equipped with an upper chamber pressure sensor, a lower chamber pressure sensor, and an actuation servo valve; The upper chamber pressure sensor connection end is connected to the actuation servo valve block, and the detection end extends into the upper chamber of the actuation cylinder to detect the hydraulic pressure in the upper chamber of the actuation cylinder when the piston rod descends. The lower chamber pressure sensor is connected to the actuation servo valve block, and the detection end extends into the lower chamber of the actuation cylinder to detect the hydraulic pressure in the lower chamber of the actuation cylinder when the piston rod rises. The P port of the actuation servo valve is connected to the main circuit interface of the actuation servo valve block, the T port is connected to the main return oil flow channel of the actuation servo valve block, the A port is connected to the A oil port of the actuation cylinder through the working flow channel of the lower chamber of the cylinder inside the actuation servo valve block, and the B port is connected to the B oil port of the actuation cylinder through the working flow channel of the upper chamber of the cylinder inside the actuation servo valve block; the pilot external oil supply port X of the actuation servo valve is connected to the external supply accumulator, and the pilot external oil discharge port Y is connected to the external discharge accumulator.

[0013] Specifically, the input / output valve block is also equipped with an input accumulator and a return oil accumulator; The input accumulator is connected in parallel to the downstream pipeline of the oil outlet of the input proportional pressure reducing valve to buffer oil shock.

[0014] The return oil accumulator is mounted in the low-pressure return oil flow channel of the input / output valve block.

[0015] Specifically, the high-pressure filter is located upstream of the main oil supply channel. The oil inlet of the high-pressure filter is connected to the external system pressure oil interface of the valve block, and the oil outlet of the high-pressure filter is directly connected to the bottom inlet of the pressure reducing valve in the balance chamber. A back pressure check valve is connected in parallel at both ends of the high-pressure filter. When the filter element is blocked or the pressure difference between the inlet and outlet exceeds the limit, the back pressure check valve opens, and the oil is supplied directly to the downstream end through the bypass channel, effectively avoiding system oil interruption and shutdown, and ensuring the continuity and stability of the hydraulic circuit oil supply.

[0016] Specifically, the balance chamber input pressure sensor is connected to the oil circuit on the inlet side of the balance chamber pressure reducing valve through a diversion channel to collect the oil supply pressure parameters at the inlet of the balance chamber pressure reducing valve in real time.

[0017] Specifically, the accumulator for input to the balance chamber is installed on the inlet side of the pressure reducing valve of the balance chamber through a built-in diversion channel in the valve block, which buffers the oil impact and stabilizes the oil supply pressure at the inlet of the pressure reducing valve.

[0018] Specifically, the balance chamber pressure reducing valve is integrated and installed on the surface of the balance servo valve block. The inlet end is connected to the upstream filtered pressure oil, and the outlet end is connected to the downstream balance chamber servo valve inlet.

[0019] A self-balancing servo cylinder system and control method Includes the following steps: Step 1: System startup preparation: After being filtered by the high-pressure filter of the balance servo valve block, the high-pressure oil is reduced in pressure by the actuation pilot oil supply pressure reducing valve and then provides the pilot oil source for the actuation servo valve; the balance chamber input pressure sensor detects the system oil supply pressure in real time, and outputs an electrical start signal when the pressure reaches the target, and the system enters the standby state; Step 2: Gradual voltage ramp-up startup of the system: When the output cut-off solenoid valve on the input / output valve block is energized and turned on, the input pressure sensor collects the outlet pressure of the input proportional pressure reducing valve in real time and forms a closed-loop feedback, controlling the input proportional pressure reducing valve to achieve stepless smooth pressure increase from zero pressure, low pressure to high pressure, providing a stable and progressive pressure oil source for the back-end test circuit; Step 3: Dynamic control of the hydraulic cylinder's ascent: When the actuation servo valve reverses its direction, pressurized oil is input into port A of the actuation cylinder, driving the actuation cylinder to extend and achieve load lifting; the balance chamber servo valve is opened synchronously to replenish oil to the balance chamber of the balance cylinder body to compensate for the change in lifting volume; the cylinder chamber pressure is collected in real time by the upper chamber pressure sensor and the lower chamber pressure sensor, and the opening of the actuation servo valve is adjusted in a closed loop to maintain stable lifting pressure. Step 4: Control of the damping for the lifting and lowering of the hydraulic cylinder: When the actuation servo valve reverses direction, pressurized oil is input into the rod chamber of port B of the actuation cylinder, driving the cylinder to retract and descend. Simultaneously, the balance chamber servo valve controls the return oil of the balance cylinder to throttle and regulate, forming controllable hydraulic damping inside the balance chamber to counteract the load inertia. At the same time, the balance chamber output pressure sensor collects the balance chamber pressure in real time and corrects the flow of the balance chamber servo valve in a closed loop to ensure a smooth descent without any jerking. Step 5: Safety Protection During the testing of the actuated cylinder, the output pressure sensor monitors the inlet pressure of the actuated servo valve in real time. When an overload or abnormal pressure is detected, the output shut-off solenoid valve quickly cuts off the main oil supply circuit. At the same time, the input proportional pressure reducing valve receives the signal and gradually reduces the pressure to zero, achieving a shock-free and safe shutdown.

[0020] In this invention, the actuation servo valve relies on real-time pressure detection feedback from pressure sensors in the upper and lower chambers of the hydraulic cylinder to form an independent closed-loop control system. This system can precisely regulate the working pressure in the upper and lower chambers of the hydraulic cylinder, eliminating problems such as pressure fluctuations, shaking, and deviation during cylinder lifting and lowering, ensuring smooth and stable cylinder lifting and lowering movements. Simultaneously, the balance servo valve collects real-time pressure signals through a pressure sensor in the balance chamber, forming a closed-loop control system for the balance chamber pressure. This dynamically adjusts the throttling resistance of the balance cylinder's return oil, replenishing the balance chamber oil in real-time throughout the entire process of cylinder lifting and lowering under load, and precisely generating hydraulic resistance matching the load, effectively offsetting the impact and inertial effects of the lifting load. This dual closed-loop control works synergistically to completely solve the pain points of traditional lifting cylinders that are prone to swaying, imbalance, and insufficient stability during rapid operation, significantly improving the equipment's operational accuracy and stability.

[0021] This system features a proportional pressure reducing valve closed-loop control structure. Relying on real-time signal feedback from the input pressure sensor, it achieves stepless continuous adjustment of hydraulic pressure, completely eliminating the rigid, gear-based pressure switching control mode of traditional hydraulic systems. During equipment startup, the system pressure gradually and steplessly increases from a low pressure of 0 to a high working pressure, providing a smoothly increasing oil supply pressure to the actuating servo valve. This ensures a smooth and gentle lifting and starting action of the cylinder, avoiding equipment wear and load fluctuations caused by sudden high-pressure shocks. When the equipment stops or encounters unexpected conditions, the system receives feedback signals and achieves stepless pressure reduction from high pressure to low pressure and back to 0, allowing the cylinder to slowly return and stop smoothly without instantaneous pressure relief shocks. This flexible, stepless pressure regulation mode is used throughout the entire process of equipment startup, operation, and shutdown, greatly mitigating the risks of equipment failure, load shedding, and hydraulic shock damage caused by sudden pressure increases and decreases, significantly improving the safety and reliability of the system operation. Attached Figure Description

[0022] Figure 1 This is a three-dimensional structural schematic diagram of the present invention; Figure 2 This is a three-dimensional structural diagram of the actuating hydraulic cylinder; Figure 3 This is a schematic diagram of a half-section of the actuating hydraulic cylinder; Figure 4 This is a schematic diagram of the side structure of the actuating cylinder; Figure 5 yes Figure 4 Schematic diagram of the A-direction structure; Figure 6 yes Figure 4Schematic diagram of the B-direction structure; Figure 7 yes Figure 4 Schematic diagram of the C-axis structure; Figure 8 This is a schematic diagram of the three-dimensional structure of the actuation servo valve block; Figure 9 This is a schematic diagram of the bottom structure of the actuation servo valve block; Figure 10 This is a schematic diagram of the three-dimensional structure of the input and output valve blocks; Figure 11 This is a schematic diagram of the three-dimensional structure of the valve block of the balance cylinder accumulator; Figure 12 This is a schematic diagram of the three-dimensional structure of the balanced servo valve block; Figure 13 This is a schematic diagram of the control logic of the present invention; Figure 14 This is a hydraulic schematic diagram of the present invention; Figure 15 yes Figure 14 Hydraulic schematic diagram of the servo valve block; Figure 16 yes Figure 14 Hydraulic schematic diagram of input / output valve block, balance cylinder accumulator valve block and balance servo valve block; Figure 17 It is a graph showing the sample weight versus inertial force (linear relationship); Figure 18 It is a graph showing the sample weight versus the maximum permissible acceleration (logarithmic relationship); Figure 19 It is the frequency vs. maximum acceleration characteristic curve; Figure 20 It is the sample weight vs. maximum acceleration characteristic curve; In the diagram, 100 is the actuating cylinder, 110 is the actuating cylinder body, 111 is the lower guide sleeve, 112 is the upper guide sleeve, 120 is the balance cylinder body, 130 is the valve block seat, 140 is the piston rod, 141 is the anti-rotation plate, 142 is the lifting pin, and 150 is the displacement sensor. 200 is the actuation servo valve block, 210 is the upper chamber pressure sensor, 220 is the lower chamber pressure sensor, 230 is the actuation servo valve, 240 is the external supply port accumulator, and 250 is the external discharge port accumulator. 300 is the input / output valve block, 310 is the input proportional pressure reducing valve, 320 is the output shut-off solenoid valve, 321 is the output pressure sensor, 330 is the input accumulator, 331 is the input pressure sensor, and 340 is the return oil accumulator. 400 is the balance cylinder accumulator valve block, 410 is the balance chamber overflow valve, 420 is the balance chamber output pressure sensor, 431 is the drain throttle valve, 432 is the accumulator drain valve, 433 is the accumulator replenishment valve, 434 is the balance chamber accumulator, 440 is the balance chamber drain port accumulator, and 450 is the actuation pilot oil supply pressure reducing valve. 500 is the balance servo valve block, 510 is the high-pressure filter, 520 is the balance chamber pressure reducing valve, 530 is the balance chamber servo valve, 540 is the balance chamber input pressure sensor, and 550 is the balance chamber input accumulator. Detailed Implementation

[0023] Embodiments of the present invention are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and should not be construed as limiting the present invention.

[0024] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0025] The following is for reference. Figure 1-16 Describe embodiments of the present invention; A self-balancing servo cylinder system, comprising: like Figure 1-7 As shown, the actuating cylinder 100 includes an actuating cylinder 110, a balance cylinder body 120, a valve block seat 130, a piston rod 140, and a displacement sensor 150. The actuating cylinder 110 and the balancing cylinder 120 are sealed and fixedly connected from top to bottom along the axial direction to form a combined balancing cylinder; the actuating cylinder 110 has a central cavity through it along the axial direction, the lower end of the central cavity is fixedly fitted with a lower guide sleeve 111, and the upper end is fixedly fitted with an upper guide sleeve 112. The piston rod 140 passes through the upper guide sleeve 112 and the lower guide sleeve 111, and adopts a hydrostatic support fit structure with the upper guide sleeve 112 and the lower guide sleeve 111; the upper guide sleeve 112 and the lower guide sleeve 111 have interconnected hydrostatic oil passages, which are respectively connected to the hydrostatic support oil inlet X3 and the hydrostatic support oil outlet L1; the inner holes of the lower guide sleeve 111 and the upper guide sleeve 112 are respectively plated with a high polymer wear-resistant material that slides with the piston rod.

[0026] The valve block seat 130 is fixedly connected to the bottom of the combined balance cylinder body 120, and is provided with an input / output valve block mounting position, a balance cylinder accumulator valve block mounting position, and a balance servo valve block mounting position. The piston portion of the piston rod 140 slides between the lower guide sleeve 111 and the upper guide sleeve 112, and the axial displacement of the piston rod 140 is monitored by the displacement sensor 150. The top end of the piston rod 140 extends from the top opening of the inner cavity of the actuating cylinder 110 and is provided with an anti-rotation plate 141. The anti-rotation plate 141 is provided with a lifting pin 142. The piston portion of the piston rod 140 is made of a high-polymer wear-resistant material, which can form a gap seal with the inner hole of the actuating cylinder 110, forming a hydrostatic support cylinder structure. A sealing ring can also be used to achieve a seal. The connection between the balance cylinder 120 and the piston rod 140 adopts a low-friction seal. The anti-rotation plate 141 is threadedly connected to the piston rod 140 bracket and moves up and down synchronously with the piston rod 140. It is in contact with the top surface of the actuating cylinder 100 through the lifting pin 142 to prevent the piston rod 140 from rotating.

[0027] The displacement sensor 150 in this case is a built-in LVDT differential transformer displacement sensor; the coil base end of the sensor is sealed and fixed to the valve block seat 130, and the measuring rod extends axially into the inner cavity of the hollow piston rod 140; the moving iron core of the displacement sensor 150 is rigidly fixed to the top of the inner cavity of the piston rod 140; when the piston rod 140 slides axially along the upper guide sleeve 112 and the lower guide sleeve 111, the moving iron core moves synchronously relative to the coil measuring rod, and the axial displacement data of the piston rod is collected in real time through differential electromagnetic induction.

[0028] The actuating cylinder body 110 is provided with an oil port A and an oil port B that communicate with the sliding cavity of the actuating cylinder 100; oil enters through the oil port A, pushing the piston of the piston rod 140 to move towards the oil port B; oil enters through the oil port B, pushing the piston of the piston rod 140 to move towards the oil port A. The balance cylinder 120 is provided with an R-port that communicates with the inner cavity. The return oil is throttled through the R-port to form a stable back pressure, which generates an upward hydraulic support force on the piston rod 140, thus achieving a smooth and rapid descent.

[0029] Specifically, such as Figure 5-6 As shown, during the upward phase, oil port A ( Figure 6 Oil enters through ports A1 and A2, pushing piston rod 140 upwards. The oil above the piston flows through port B (…). Figure 6 Oil returns from ports B1 and B2; at this time, oil slowly enters through port R until the inner cavity corresponding to port R is filled.

[0030] During the downward phase, pressurized oil enters the upper chamber of the actuating cylinder 110 through port B (the area above the piston is called the upper chamber, and vice versa), pushing the piston downward. The oil in the lower chamber returns through port A. At the same time, the return oil through port R throttles to form a stable back pressure, generating an upward hydraulic support force on the piston rod, achieving a smooth and rapid descent. The displacement sensor provides real-time feedback on the piston rod position, and the servo valve block dynamically adjusts the flow rate of each chamber accordingly, forming a closed-loop control to ensure the smoothness and positional accuracy of the lifting and lowering action.

[0031] Figure 3 In this design, X3 serves as the hydrostatic support port for the upper guide sleeve 112 and the lower guide sleeve 111. Oil enters the upper guide sleeve 112 and the lower guide sleeve 111 through X3. The inner walls of the upper guide sleeve 112 and the lower guide sleeve 111 are respectively provided with annular hydrostatic oil chambers and circumferentially distributed oil grooves. This structure, in conjunction with the oil, provides hydrostatic support to the piston rod 140, ensuring that the piston rod 140 remains centered. The oil in the guide sleeves is ultimately discharged through the hydrostatic support drain port L1. L2 is the drain port for the balance cylinder 120. The oil in the bottom cavity of the balance cylinder 120 provides hydrostatic support to the bottom end of the piston rod 140, and any leaked oil generated inside the cylinder flows out through the drain port L2. This design incorporates hydrostatic support structures at the upper, middle, and lower parts of the piston rod 140, effectively improving the alignment accuracy and operational stability of the piston rod.

[0032] like Figure 8-9 As shown, one or more actuation servo valve blocks 200 are provided and connected to the side of the actuation cylinder 100; the actuation servo valve block 200 is provided with an upper chamber pressure sensor 210, a lower chamber pressure sensor 220 and an actuation servo valve 230; The upper chamber pressure sensor 210 is connected to the actuation servo valve block 200, and the detection end extends into the upper chamber of the actuation cylinder 110 to detect the hydraulic pressure in the upper chamber of the actuation cylinder 110 when the piston rod 140 descends. The lower chamber pressure sensor 220 is connected to the actuation servo valve block 200, and its detection end extends into the lower chamber of the actuation cylinder 110 to detect the hydraulic pressure in the lower chamber of the actuation cylinder 110 when the piston rod 140 rises. The two sensors transmit feedback signals to the actuation servo valve to form a closed-loop control, thereby stabilizing the hydraulic pressure in the upper and lower chambers during the lifting and lowering of the piston rod 140.

[0033] The P port of the actuation servo valve 230 is connected to the main circuit interface of the actuation servo valve block 200, the T port is connected to the main return oil flow channel of the actuation servo valve block 200, the A port is connected to the A oil port of the actuation cylinder body 110 through the working flow channel of the lower chamber of the inner cylinder of the actuation servo valve block 200, and the B port is connected to the B oil port of the actuation cylinder 110 through the working flow channel of the upper chamber of the inner cylinder of the actuation servo valve block 200; the pilot external oil supply port X of the actuation servo valve 230 is connected to the external supply port accumulator 240, and the pilot external oil discharge port Y is connected to the external discharge port accumulator 250. This system has a rated operating pressure of 28MPa, classifying it as a high-pressure hydraulic system with significant pressure fluctuations in the main oil circuit. The external accumulator 240 can independently store pressurized oil, continuously and smoothly supplying stable control oil to the servo valve pilot control chamber. Unaffected by main oil circuit pressure fluctuations, this ensures continuous and precise servo valve spool reversal and opening adjustment, preventing spool jamming and operational deviation due to unstable control oil pressure. This provides a foundation for reliable servo valve control under high-pressure conditions. During servo valve operation, the control chamber continuously leaks oil. If this leakage is directly discharged into the return oil line, it can easily cause pressure shocks and oil pulsations. The external accumulator 250 buffers and stabilizes the leakage, absorbing pressure pulsations and ensuring smooth oil discharge from the servo valve control chamber. This reduces the interference of leakage shocks on the spool state, further improving the smoothness of servo valve operation and overall control accuracy. During operation, the control logic of the actuating servo valve 230 enables a gradual increase in system pressure from closed to low pressure to high pressure, and a gradual decrease from high pressure to low pressure to closed, avoiding high-pressure surges. In automatic operation, in case of an emergency, pressing the emergency stop button will quickly cut off the pressure oil supply to the servo valve and connect the already output pressure oil to the return oil line. Two sets of accumulators respectively stabilize and buffer the pilot oil supply and discharge, enabling independent pressure stabilization of the servo valve pilot circuit, adapting to a 28MPa high-pressure working environment, and effectively improving the operational reliability, response consistency, and service life of the actuating servo valve 230. The actuating servo valve 230 in this case features gradual pressure increase, gradual pressure decrease, and emergency shut-off and unloading control functions.

[0034] like Figure 4 and Figure 9 As shown, during installation Figure 4 Ports A, B, T, P, X, and Y are respectively connected to... Figure 9 Ports A, B, T, P, X, and Y correspond to each other. P, A, B, T, X, and Y correspond to the P, A, B, T, X, and Y ports of the actuation servo valve block 200 on the same side. In this case, actuation servo valve blocks 200 are provided on both sides of the actuation cylinder 100. To easily distinguish between different sides, the corresponding ports are labeled 1 and 2; for example, ports P are labeled P1 and P2 in the diagram, and ports A are labeled A1 and A2, etc.

[0035] like Figure 10As shown, the input / output valve block 300 has independent and zoned high-pressure oil supply channels and low-pressure oil return channels inside, which can effectively avoid cross-pressure and cross-fluid faults. The input / output valve block 300 is equipped with an input proportional pressure reducing valve 310, an output shut-off solenoid valve 320, an input accumulator 330, and a return oil accumulator 340. The functional components are connected and coordinated in an orderly manner through the internal flow channels of the valve block, forming an integrated hydraulic control circuit that integrates pressure closed-loop regulation, hydraulic shock buffering, fault safety shut-off, and return oil pulsation suppression. The input proportional pressure reducing valve 310 is installed in the high-pressure oil supply channel of the input-output valve block 300. The oil inlet of the input proportional pressure reducing valve 310 is connected to the external system pressure oil source through the high-pressure oil supply channel inside the valve block, and the oil outlet forms a multi-way parallel interface through the built-in diversion channel.

[0036] The input accumulator 330 is assembled to the bypass mounting position of the input / output valve block 300 corresponding to the high-pressure oil supply channel through a threaded sealing interface, and the input accumulator 330 is connected in parallel to the downstream pipeline of the oil outlet of the input proportional pressure reducing valve 310 to buffer the hydraulic shock during the system pressurization process and ensure stable downstream oil supply pressure.

[0037] The output shut-off solenoid valve 320 is installed in the high-pressure oil supply channel of the input-output valve block 300, located between the oil supply interface of the input proportional pressure reducing valve 310 and the actuation servo valve 230. The oil inlet of the output shut-off solenoid valve 320 is connected to the main oil supply channel on the oil outlet side of the input proportional pressure reducing valve 310, and the oil outlet is connected to the oil supply port of the actuation servo valve 230 outside the valve block through the internal flow channel of the valve block, thereby realizing the controllable on / off of the main oil supply circuit. At the same time, an output pressure sensor 321 is provided at the output shut-off solenoid valve 320, which is synchronously connected to the oil outlet side flow channel. It can collect the oil supply pressure signal in real time and trigger the valve body to switch on and off under abnormal operating conditions, so as to complete the gradual pressure reduction linkage control in conjunction with the input proportional pressure reducing valve 310.

[0038] The return oil accumulator 340 is assembled into the low-pressure return oil passage of the input / output valve block 300 via a sealed threaded interface, and is connected to the low-pressure return oil pipeline between the return oil interface of the actuation servo valve 230 and the system's main return oil passage. The return oil accumulator 340 can absorb the pressure pulsation caused by the sudden change in return oil flow during the reciprocating motion of the cylinder in real time, stabilize the pressure in the return oil pipeline, effectively suppress pipeline vibration, and improve the overall operational stability of the hydraulic system.

[0039] In this case, the core function of the input / output valve block 300 is to provide closed-loop controllable progressive pressure oil to the actuating servo valve 230, and to achieve rapid shut-off and pressure stabilization protection under fault conditions, which is divided into three stages: normal operation, closed-loop pressure stabilization, and fault protection. When the system starts, external pressure oil enters the input proportional pressure reducing valve 310. The input proportional pressure reducing valve 310 opens gradually according to the control signal, and the output pressure slowly rises from 0 to the set value.

[0040] The input accumulator 330 is synchronously filled with oil, providing stable and shock-free pressure oil to the actuating servo valve 230 when the output pressure of the input proportional pressure reducing valve 310 fluctuates.

[0041] The input pressure sensor 331 collects the actual pressure signal of the input proportional pressure reducing valve 310 in real time and feeds it back to the control system for comparison with the target pressure value. The control system adjusts the control current of the input proportional pressure reducing valve 310 according to the feedback signal, dynamically corrects the output pressure, and realizes a smooth pressure increase process from "no pressure → low pressure → high pressure". This ensures that the oil inlet pressure of the actuating servo valve 230 is consistent with the command and avoids cylinder vibration caused by sudden pressure changes.

[0042] When the system detects an abnormal pressure signal (such as overload or leakage) from the output pressure sensor 321, the control system triggers the protection logic: the output cut-off solenoid valve 320 de-energizes and cuts off the oil supply to the actuation servo valve 230, preventing high-pressure oil from continuing to enter the cylinder circuit; at the same time, a control signal is sent to the input proportional pressure reducing valve 310, driving the input proportional pressure reducing valve 310 to gradually close, so that the output pressure decreases slowly, avoiding system shock caused by sudden pressure relief; the return oil accumulator on the return oil side absorbs the flow pulsation discharged into the return oil pipeline when the cylinder is actuated, stabilizes the return oil pressure, and reduces pipeline vibration and noise.

[0043] To maintain stable hydraulic pressure at the balance cylinder during rapid downward movement of the hydraulic cylinder, a balance cylinder accumulator assembly was designed. The balance cylinder accumulator assembly mainly includes: like Figure 11 As shown, the balance cylinder accumulator valve block 400 is equipped with a balance chamber overflow valve 410, a balance chamber output pressure sensor 420, an accumulator charging and discharging control component, a balance chamber drain accumulator 440, and an actuation pilot oil supply pressure reducing valve 450. These components are systematically connected through precise internal flow channels within the valve block, forming an integrated hydraulic control circuit that provides closed-loop control of the balance chamber pressure, automatic accumulator charging and discharging, system safety overflow protection, pilot pressure stabilization, and drain pulsation suppression. This circuit fully adapts to the steady-state operation, pressure regulation, safety protection, and shutdown maintenance requirements of the balance cylinder hydraulic system. The components are arranged according to functional zones. Pressure safety protection and detection components and accumulator charging and discharging control components are centrally located in the main pressure flow channel area of ​​the valve block. The pilot oil supply pressure reducing valve is integrated into the pilot oil circuit area of ​​the valve block, and the drain accumulator is located in the low-pressure drain flow channel area. The high and low pressure flow channels are independently zoned, eliminating the risk of cross-pressure and fluid leakage. The layout is neat and facilitates future maintenance and component replacement.

[0044] The balance chamber overflow valve 410 is integrated into the bypass position of the main pressure flow channel of the balance chamber and connected in parallel in the pressure oil circuit of the balance chamber, serving as a core safety protection component of the system. Its inlet connects to the high-pressure oil channel of the balance chamber, and its outlet connects to the main drain flow channel inside the valve block. It can monitor the working pressure of the balance chamber in real time. When the system pressure suddenly rises abnormally and exceeds the rated working pressure, it automatically opens to overflow and relieve pressure, introducing high-pressure oil into the drain circuit to quickly release the excess pressure of the system and prevent damage to the balance chamber, accumulator and pipeline components due to overpressure, thus achieving passive safety protection against system overpressure.

[0045] The pressure sensor 420 for the balance chamber output is sealed and installed at the main oil circuit detection port of the balance chamber pressure output. The detection end is directly connected to the working flow channel of the balance chamber, which can collect the real-time working pressure of the balance chamber in real time and accurately, and feed back the pressure analog signal to the control system and the balance chamber servo valve in real time. This constructs a closed-loop control logic for the balance chamber pressure, provides accurate signal basis for the servo valve pressure regulation, ensures that the working pressure of the balance chamber is always stably maintained within the set range, and improves the working stability and control accuracy of the balance cylinder.

[0046] The accumulator charging and discharging control assembly includes a discharge throttle valve 431, an accumulator discharge valve 432, and an accumulator replenishment valve 433 connected in series on the charging and discharging flow channels of the accumulator 434 in the balance chamber, forming a controllable charging and discharging regulation circuit. The accumulator replenishment valve 433 is connected to the system pressure oil source, the discharge throttle valve 431 is a flow regulation element that controls the oil flow rate during the charging and discharging process, preventing hydraulic shock caused by sudden flow changes; the accumulator discharge valve 432 is connected to the system return oil pipeline. These three components work together to achieve controllable regulation of the accumulator 434 under all operating conditions, including pre-charging, replenishment during operation, and slow discharge during shutdown. The accumulator 434 of the balance chamber is installed in parallel in the main working oil circuit of the balance chamber through a sealed threaded interface and is directly connected to the working chamber of the servo valve of the balance chamber. It can compensate for pressure fluctuations in the balance chamber in real time, continuously provide stable and continuous hydraulic pressure to the balance chamber, offset the pressure deviation caused by load fluctuations and pipeline pressure loss, ensure constant pressure during the operation of the balance cylinder, and eliminate problems such as pressure jitter and deviation.

[0047] The accumulator 440 of the balance chamber drain port is integrated into the low-pressure drain flow channel port of the balance cylinder accumulator valve block 400 and connected in parallel in the system drain circuit. It is specifically used to absorb the pressure pulsation caused by the sudden change in drain flow during the operation and depressurization of the balance chamber, stabilize the drain pipeline pressure, suppress pipeline vibration caused by the drain process, and optimize the stable operation of the system's low-pressure circuit.

[0048] The actuation pilot oil supply pressure reducing valve 450 is integrated into the pilot oil supply circuit of the balance cylinder accumulator valve block 400. It provides the rated pilot working pressure for the actuation servo valve, and provides the actuation servo valve with constant pressure and controllable precision pilot oil supply, ensuring that the actuation servo valve operates accurately and smoothly, and meeting the control requirements of the equipment lifting action.

[0049] The pressure sensor 420 of the balance chamber output collects the working pressure of the balance chamber in real time and feeds it back to the control system and the balance chamber servo valve, forming a pressure closed-loop regulation and dynamically correcting the pressure deviation of the balance chamber. At the same time, the balance chamber accumulator 434 continuously stabilizes and replenishes pressure, absorbing pressure pulsations during system operation, maintaining a constant balance chamber pressure, and ensuring steady-state operation of the balance cylinder. When the system experiences a momentary overpressure condition, the balance chamber overflow valve 410 immediately opens to overflow and relieve pressure, realizing overpressure safety protection of the system and avoiding the risk of overpressure damage.

[0050] The oil filling operation of the balance chamber accumulator 434 is divided into two stages: low-pressure pre-charging and high-pressure replenishment. The entire process is automated by the accumulator charging and discharging control components linked by electronic control signals. During the initial oil filling, the control system outputs a signal to simultaneously energize and open the accumulator replenishment valve 433 and the accumulator discharge valve 432. The system pressure oil enters the filling channel through the accumulator replenishment valve 433, flows sequentially through the discharge throttle valve 431 and the accumulator discharge valve 432, and returns to the oil tank. The low-pressure pre-charging operation of the balance chamber accumulator 434 is completed through throttling and flow restriction, effectively avoiding the hydraulic shock caused by high-pressure instantaneous oil filling. After the low-pressure pre-charging is completed, the accumulator discharge valve 432 is de-energized and closed, cutting off the return oil passage. The system pressure oil continues to replenish the balance chamber accumulator 434 with high pressure through the accumulator replenishment valve 433. During this process, the pressure sensor 420 of the balance chamber outputs real-time monitoring of the circuit pressure. When the pressure reaches the system's set working pressure, the control system triggers a signal, the accumulator oil replenishment valve 433 is de-energized and closed, the oil filling operation ends, and the balance chamber accumulator 434 enters the stable energy storage state.

[0051] When the equipment is idle for a long period, stored offline, or transported, and it is necessary to depressurize and drain the oil from the balance chamber accumulator 434, the control system triggers the drain logic, energizing and opening the accumulator drain valve 432. The high-pressure oil stored inside the balance chamber accumulator 434 flows out under the action of pressure difference. After being limited and stabilized by the drain throttle valve 431, it slowly flows back to the oil tank through the accumulator drain valve 432, achieving controllable and slow depressurization and preventing pipeline impact and vibration caused by instantaneous depressurization. During the depressurization process, the balance chamber output pressure sensor 420 collects the circuit pressure in real time. When the pressure drops to the system's set safe pressure threshold, the control system determines that the depressurization is complete and simultaneously controls the accumulator drain valve 432 and the accumulator replenishment valve 433 to de-energize and reset, completely closing the charging and discharging circuit and completing the safe oil draining operation of the balance chamber accumulator 434.

[0052] Throughout the entire process of system operation, overflow pressure relief, and oil charging and discharging of the balance chamber accumulator 434, the balance chamber drain port accumulator 440 continuously acts on the low-pressure drain circuit, absorbing the pulsating energy generated by sudden changes in drain flow and pressure fluctuations in real time, stabilizing the drain pipeline pressure, eliminating pipeline vibration, hard pipe knocking, hose shaking and other phenomena, and greatly improving the operational stability and service life of the entire balance cylinder hydraulic system.

[0053] In order to provide the required pressure oil to the balance chamber, a balance servo valve block 500 is assembled on the balance servo valve block mounting position of the valve block seat 130, and the specific structure is as follows: like Figure 12 As shown, the balance servo valve block 500 has a main oil supply channel internally connected to a high-pressure filter 510, a balance chamber pressure reducing valve 520, and a balance chamber servo valve 530. The inlet side of the balance chamber pressure reducing valve 520 is connected to the balance chamber input pressure sensor 540 and the balance chamber input accumulator 550 through the internal flow channels of the balance servo valve block 500, forming an integrated balance hydraulic oil supply circuit that integrates filtration, pressure stabilization, pressure detection, pressure reduction regulation, and servo control. In this case, the balance chamber servo valve 530 is used to replenish oil to the balance chamber when the actuating cylinder 100 moves upward. When the actuating cylinder 100 moves downward, the opening of the balance chamber servo valve 530 establishes a stable pressure in the balance chamber, balancing the weight of the test sample and its tooling fixture, ensuring that the actuating cylinder 100 moves smoothly downward.

[0054] Specifically: The high-pressure filter 510 is located upstream of the main oil supply channel. The oil inlet of the high-pressure filter 510 is connected to the external system pressure oil interface of the valve block, and the oil outlet of the high-pressure filter 510 is directly connected to the bottom inlet of the balance chamber pressure reducing valve 520. Back pressure check valves are connected in parallel at both ends of the high-pressure filter 510. When the filter element is blocked or the pressure difference between the inlet and outlet exceeds the limit, the back pressure check valve opens, and the oil is supplied directly to the downstream end through the bypass channel, effectively avoiding system oil interruption and shutdown, and ensuring the continuity and stability of the hydraulic circuit oil supply.

[0055] Specifically: The balance chamber input pressure sensor 540 is connected to the oil circuit on the inlet side of the balance chamber pressure reducing valve 520 through a diversion channel, and collects the oil supply pressure parameters at the inlet of the balance chamber pressure reducing valve 520 in real time, and feeds back the analog signal to the equipment control system in real time, providing accurate data support for system pressure closed-loop control, fault monitoring and pressure parameter calibration.

[0056] Specifically: The balanced chamber input accumulator 550 is installed on the inlet side of the balanced chamber pressure reducing valve 520 through the built-in diversion channel of the valve block, which can buffer the oil impact, stabilize the oil supply pressure at the inlet of the pressure reducing valve, reduce the interference of system flow fluctuations on the downstream pressure reducing circuit and servo control circuit, and improve the smoothness of the whole machine operation.

[0057] Specifically: The balance chamber pressure reducing valve 520 is integrated and installed on the valve body surface of the balance servo valve block 500. The inlet end is connected to the upstream filtered pressure oil, and the outlet end is connected to the oil inlet of the downstream balance chamber servo valve 530. The balance chamber pressure reducing valve 520 continuously reduces and stabilizes the inlet high pressure oil, providing the downstream balance chamber servo valve 530 with a constant pressure and controllable accuracy working oil source. Its external oil drain port is connected to the system return oil pipeline through the valve block's independent dedicated oil drain channel, avoiding internal leakage of oil from interfering with the pressure stability of the main circuit.

[0058] Specifically, the balance chamber servo valve 530 is integrated and installed at the end of the main oil supply channel. Its oil inlet is connected to the outlet oil circuit of the balance chamber pressure reducing valve 520, and its oil return port is connected to the main return oil channel inside the balance servo valve block 500. The working oil port is connected to the balance chamber of the external balance cylinder through the control channel of the balance servo valve block 500. The balance chamber servo valve 530 can accurately adjust the pressure and flow rate of the output oil according to the electronic control command, so as to realize high-precision pressure compensation, attitude correction and dynamic balance control of the balance chamber of the balance cylinder.

[0059] like Figure 14-16 A self-balancing servo cylinder system and control method. Includes the following steps: Step 1: System startup preparation: Open the shut-off valves of the P, T, and L pipelines of the system, and the high-pressure oil of the system is connected to the circuit. After being filtered by the high-pressure filter 510 of the balance servo valve block 500, the high-pressure oil is reduced by the pressure reducing valve 450 and then provides the pilot oil source for the actuation servo valve 230. At the same time, the high-pressure oil is connected, and the static pressure support pressure port of the actuation cylinder 100 is supported. The pressure sensor 540 of the balance chamber detects the system oil supply pressure in real time. After the pressure reaches the target, it outputs an electrical start signal and the system enters the standby state. Step 2: Gradual voltage ramp-up startup of the system: When the output shut-off solenoid valve 320 on the input / output valve block 300 is energized and turned on, the input pressure sensor 331 collects the outlet pressure of the input proportional pressure reducing valve 310 in real time and forms a closed-loop feedback, controlling the input proportional pressure reducing valve 310 to achieve stepless smooth pressure increase from zero pressure, low pressure to high pressure, providing a stable and progressive pressure oil source for the back-end test circuit. In this case, the input pressure sensor 331 and the input proportional pressure reducing valve 310 form an independent pressure closed loop. The control system dynamically adjusts the current parameter of the input proportional pressure reducing valve 310 according to the real-time pressure deviation, so as to realize the stepless and flexible increase of the test system pressure and prevent pressure change from interfering with the lifting mechanics test data.

[0060] Step 3: Dynamic control of the hydraulic cylinder's ascent: When the actuation servo valve 230 is switched on, pressurized oil is input to port A of the actuation cylinder 100, enters the lower chamber of the cylinder, and drives the actuation cylinder 100 to extend and achieve load lifting; at the same time, the balance chamber servo valve 530 is opened to replenish oil to the balance chamber of the balance cylinder 120 to compensate for the change in lifting volume; the cylinder chamber pressure is collected in real time by the upper chamber pressure sensor 210 and the lower chamber pressure sensor 220, and the opening degree of the actuation servo valve 230 is adjusted in a closed loop to maintain stable lifting pressure; Step 4: Control of hydraulic cylinder descent damping: The actuation servo valve 230 reverses direction, and pressurized oil is input into the rod chamber of the actuation cylinder 100B port, driving the cylinder to retract and descend. Simultaneously, the balance chamber servo valve 530 controls the return oil of the balance cylinder 120 to throttle and regulate it, forming controllable hydraulic damping inside the balance chamber to counteract the load inertia. At the same time, the balance chamber output pressure sensor 420 collects the balance chamber pressure in real time and corrects the flow of the balance chamber servo valve 530 in a closed loop to ensure a smooth descent without any jerking. The upper chamber pressure sensor 210, lower chamber pressure sensor 220, and actuation servo valve 230 form a closed-loop hydraulic cylinder pressure system, while the balance chamber output pressure sensor 420 and balance chamber servo valve 530 form a balanced damping pressure closed-loop system. This dual-loop synchronous control achieves precise and stable dynamic pressure throughout the lifting and lowering process, ensuring the accuracy and repeatability of lifting mechanics dynamic test data. Simultaneously, through precise throttling damping adjustment of the balance chamber servo valve 530, corresponding damping resistance can be matched according to different lifting loads and test speeds, adapting to the needs of multi-condition lifting mechanics dynamic testing and suppressing overspeed and vibration phenomena.

[0061] Step 5: Safety Protection During the upward movement of the actuating cylinder, the output pressure sensor 321 monitors the inlet pressure of the actuating servo valve 230 in real time. When an emergency working condition such as overload or abnormal pressure is detected, the output shut-off solenoid valve 320 quickly cuts off the main oil supply circuit. At the same time, the input proportional pressure reducing valve 310 receives the signal and gradually reduces the pressure to zero, achieving a safe shutdown without impact. Step Six: Accumulator Charge / Discharge Pressure Adaptation Test Conditions: When the system is running for the first time or the test pressure is insufficient, the accumulator oil replenishment valve 433 is energized to fill the balance chamber accumulator 434 with oil for energy storage; when the test ends or the system is reset, the accumulator oil discharge valve 432 is energized to cooperate with the oil discharge throttle valve 431 to achieve smooth oil discharge and pressure relief.

[0062] like Figure 13 As shown, the control logic of this invention is mainly as follows: 1. System startup trigger: When the system main pressure oil P is connected to the input proportional pressure reducing valve 310, the balance cylinder output pressure sensor 420 collects the balance chamber output oil circuit pressure in real time. When the detected pressure reaches the preset start-up threshold, the pressure signal is sent to the control system as the start-up trigger signal of the whole machine. This simultaneously wakes up the core hydraulic control components, including the input proportional pressure reducing valve 310, two sets of actuation servo valves 230, accumulator oil replenishment valve 433, accumulator oil discharge valve 432, and balance chamber servo valve 530, so that each valve enters the standby ready state, providing the pre-start conditions for the operation of functions such as cylinder pressure regulation, attitude balancing, and accumulator oil charging and discharging.

[0063] 2. Closed-loop control of hydraulic cylinder pressure: This system is equipped with two completely independent closed-loop pressure circuits for the actuated cylinders, with consistent control logic between the two circuits: each actuated cylinder is equipped with an upper chamber pressure sensor 210, a lower chamber pressure sensor 220, and a corresponding actuation servo valve 230 to form a pressure closed-loop control system; during operation, the upper and lower chamber pressure sensors collect the hydraulic oil pressure in the upper and lower chambers of the actuated cylinder in real time and transmit the pressure feedback signal to the control system; the control system compares the deviation between the actual pressure and the target pressure and dynamically adjusts the valve core opening of the actuation servo valve 230 to accurately control the oil supply flow and output pressure entering the cylinder; the actual cylinder pressure after adjustment by the servo valve is again transmitted back to the control system through the pressure sensor, forming a continuous dynamic closed-loop adjustment, compensating for pressure deviations caused by load fluctuations and hydraulic shocks in real time, stabilizing and maintaining a constant working pressure of the actuated cylinder, and improving the cylinder pressure control accuracy.

[0064] 3. Dual pressure closed-loop control in the balance chamber: The system is configured with two independent closed-loop pressure balancing circuits, which work together to achieve high-precision pressure stabilization of the balancing cylinder. The two closed-loop circuits perform separate control functions: Input pressure reduction closed loop: The input pressure sensor 540 of the balance cylinder and the input proportional pressure reducing valve 310 form a pressure reduction closed loop. The sensor collects the oil supply pressure output by the pressure reducing valve to the balance cylinder in real time. The control system corrects the output oil pressure of the input proportional pressure reducing valve 310 according to the pressure deviation, so as to achieve precise pressure regulation of the oil inlet pressure of the balance cylinder. Balance chamber servo closed loop: The balance cylinder output pressure sensor 420 and the balance chamber servo valve 530 form a balance chamber working pressure closed loop. The sensor collects the working pressure in the balance cylinder 120 chamber in real time and adjusts the on / off state and flow of the balance chamber servo valve 530 in linkage. Two sets of closed-loop coordinated control and dual correction of the hydraulic pressure in the balancing chamber ensure stable equipment operation.

[0065] 4. Synchronous control of hydraulic cylinder displacement: Each actuating cylinder 100 is equipped with a built-in displacement sensor 150. The displacement sensor collects the cylinder extension stroke and running speed signals in real time and feeds them back to the control system. When multiple sets of actuating cylinders operate synchronously, the control system adjusts the oil supply flow and action sequence of each set of actuating servo valves 230 according to the real-time displacement and speed feedback data of each cylinder. This dynamically compensates for the deviation in the speed of a single cylinder, eliminates the problem of asynchronous action and uneven force of multiple cylinders, and realizes synchronous and stable lifting of multiple cylinders.

[0066] 5. System pressure overload graded protection: The main oil circuit P is equipped with input pressure sensor 331 and output pressure sensor 321 to monitor the main oil supply pressure in real time. When equipment overload, sudden load change, oil circuit blockage, or other faults cause the main oil circuit pressure to exceed the safety threshold, output pressure sensor 321 sends a fault signal to the control system, triggering tiered linkage protection. The control system drives the output cut-off solenoid valve 320 to switch, quickly cutting off the main oil supply circuit to the two sets of actuation servo valves 230 and stopping the oil supply to the actuator cylinder; simultaneously, it sends adjustment commands to the input proportional pressure reducing valve 310, controlling its output oil pressure to gradually decrease to zero; it adopts a graded protection logic of "cutting off the oil supply first and then gradually depressurizing" to avoid hydraulic shock caused by instantaneous large pressure relief and protect all hydraulic valves and cylinder structures.

[0067] 6. Accumulator oil charging and voltage stabilization control: After the control system sends a replenishment start signal, the accumulator replenishment valve 433 is energized and switches to open the oil circuit. The high-pressure oil in the system flows into the balance chamber accumulator 434 through the replenishment valve to complete the oil filling and energy storage. The accumulator stores high-pressure oil for system operation pressure stabilization, pressure pulsation offsetting, and instantaneous large-flow oil replenishment.

[0068] After the control system issues an oil start signal, the accumulator drain valve 432 is energized and opened. The high-pressure oil inside the balance chamber accumulator 434 passes through the drain throttle valve 431 and the accumulator drain valve 432 in sequence to return oil and relieve pressure. This circuit is used for equipment shutdown reset, pipeline maintenance, and overall system pressure relief in fault conditions.

[0069] Regarding the information disclosed in this case, the following points need to be clarified: (1) The accompanying drawings of the embodiments disclosed in this case only involve the structures involved in the embodiments disclosed in this case. Other structures can refer to the general design. (2) Where there is no conflict, the embodiments and features disclosed in this case can be combined with each other to obtain new embodiments; The above are merely specific embodiments disclosed in this case, but the scope of protection of this disclosure is not limited thereto. The scope of protection disclosed in this case shall be determined by the scope of protection of the claims.

Claims

1. A servo cylinder system capable of self-balancing gravitational inertia, characterized in that, include: The actuating cylinder (100) includes an actuating cylinder body (110), a balance cylinder body (120), a valve block seat (130), a piston rod (140), and a displacement sensor (150). The actuating cylinder (110) and the balancing cylinder (120) are sealed and fixedly connected from top to bottom along the axial direction to form a combined balancing cylinder; the actuating cylinder (110) has a central cavity that runs through it along the axial direction, and the lower guide sleeve (111) is fixedly installed at the lower end of the central cavity, and the upper guide sleeve (112) is fixedly installed at the upper end. The piston rod (140) passes through the upper guide sleeve (112) and the lower guide sleeve (111), and adopts a hydrostatic support structure with the upper guide sleeve (112) and the lower guide sleeve (111); The valve block seat (130) is fixedly connected to the bottom of the combined balance cylinder body, and is provided with an input / output valve block mounting position, a balance cylinder accumulator valve block mounting position and a balance servo valve block mounting position; The piston portion of the piston rod (140) slides between the lower guide sleeve (111) and the upper guide sleeve (112), and the axial travel displacement of the piston rod (140) is monitored by the displacement sensor (150). The actuation servo valve block (200) is integrated with an upper chamber pressure sensor (210), a lower chamber pressure sensor (220), and an actuation servo valve (230). The upper chamber pressure sensor (210) detects the hydraulic pressure in the upper chamber of the actuation cylinder (110) during the descent of the piston rod (140). The lower chamber pressure sensor (220) detects the hydraulic pressure in the lower chamber of the actuation cylinder (110) during the ascent of the piston rod (140). Each main oil port of the actuation servo valve (230) is connected to the main circuit, the main return oil channel of the actuation servo valve block (200), and the corresponding oil port of the actuation cylinder (110). Its pilot external oil supply port X and pilot external oil discharge port Y are respectively connected to the external supply accumulator (240) and the external discharge accumulator (250). The input / output valve block (300) has an independent high-pressure oil supply channel and a low-pressure oil return channel inside; the high-pressure oil supply channel is equipped with an input proportional pressure reducing valve (310) and an output cut-off solenoid valve (320); the output cut-off solenoid valve (320) is located between the input proportional pressure reducing valve (310) and the oil supply interface of the actuation servo valve (230); The balance cylinder accumulator valve block (400) is equipped with a balance chamber overflow valve (410), a balance chamber output pressure sensor (420), an accumulator charging and discharging control assembly, a balance chamber drain port accumulator (440), and an actuation pilot oil supply pressure reducing valve (450). The balance chamber overflow valve (410) is integrated in the bypass position of the main pressure flow channel of the balance chamber. Its inlet is connected to the high pressure oil passage of the balance chamber, and its outlet is connected to the main oil drain flow channel inside the valve block. The balance chamber output pressure sensor (420) is installed at the main oil circuit detection port of the balance chamber pressure output. The accumulator charging and discharging control assembly includes a discharge throttle valve (431), an accumulator discharge valve (432), and an accumulator replenishment valve (433) connected in series on the charging and discharging flow channel of the balance chamber accumulator (434); the balance chamber accumulator (434) is installed in the main working oil circuit of the balance chamber and is directly connected to the working chamber of the balance chamber servo valve. The accumulator (440) of the balance chamber drain port is integrated into the low-pressure drain flow channel port of the balance cylinder accumulator valve block (400) and connected in parallel in the system drain circuit; The actuation pilot oil supply pressure reducing valve (450) is integrated into the pilot oil supply circuit of the balance cylinder accumulator valve block (400) to provide the actuation servo valve (230) with a suitable pilot control pressure. The balance servo valve block (500) has a main oil supply channel that is sequentially connected to a high-pressure filter (510), a balance chamber pressure reducing valve (520), and a balance chamber servo valve (530). The inlet side of the balance chamber pressure reducing valve (520) is connected to the balance chamber input pressure sensor (540) and the balance chamber input accumulator (550) through the internal flow channel of the balance servo valve block (500), forming an integrated balance hydraulic oil supply circuit.

2. The servo cylinder system capable of self-balancing gravitational inertia according to claim 1, characterized in that, The actuating cylinder body (110) is provided with an A oil port and a B oil port that communicate with the sliding cavity of the actuating oil cylinder (100); oil enters through the A oil port and pushes the piston of the piston rod (140) to move towards the B oil port; oil enters through the B oil port and pushes the piston of the piston rod (140) to move towards the A oil port. The balance cylinder (120) is provided with an R oil port that communicates with the inner cavity. The return oil is throttled through the R oil port to form a stable back pressure, which generates an upward hydraulic support force on the piston rod (140) to achieve a smooth and rapid descent.

3. The servo cylinder system capable of self-balancing gravitational inertia according to claim 1, characterized in that, The piston rod (140) extends from the top opening of the inner cavity of the actuating cylinder (110) and is provided with an anti-rotation plate (141); the anti-rotation plate (141) is provided with a lifting pin (142).

4. A servo cylinder system capable of self-balancing gravitational inertia according to claim 1, characterized in that, The actuation servo valve block (200) is connected to the side of the actuation cylinder (100); the actuation servo valve block (200) is provided with an upper chamber pressure sensor (210), a lower chamber pressure sensor (220) and an actuation servo valve (230). The upper chamber pressure sensor (210) is connected to the actuation servo valve block (200) at its connection end, and its detection end extends into the upper chamber of the actuation cylinder (110) to detect the hydraulic pressure in the upper chamber of the actuation cylinder (110) when the piston rod (140) descends. The lower chamber pressure sensor (220) is connected to the actuation servo valve block (200), and the detection end extends into the lower chamber of the actuation cylinder (110) to detect the hydraulic pressure in the lower chamber of the actuation cylinder (110) when the piston rod (140) rises. The P port of the actuation servo valve (230) is connected to the main circuit interface of the actuation servo valve block (200), the T port is connected to the main return oil flow channel of the actuation servo valve block (200), the A port is connected to the A oil port of the actuation cylinder body (110) through the working flow channel of the lower chamber of the cylinder inside the actuation servo valve block (200), and the B port is connected to the B oil port of the actuation cylinder (110) through the working flow channel of the upper chamber of the cylinder inside the actuation servo valve block (200); the pilot external oil supply port X of the actuation servo valve (230) is connected to the external supply accumulator (240), and the pilot external oil discharge port Y is connected to the external discharge accumulator (250).

5. A servo cylinder system capable of self-balancing gravitational inertia according to claim 1, characterized in that, The input / output valve block (300) is also provided with an input accumulator (330) and a return oil accumulator (340). The input accumulator (330) is connected in parallel to the downstream pipeline of the oil outlet of the input proportional pressure reducing valve (310) to buffer oil shock. The return oil accumulator (340) is mounted in the low-pressure return oil passage of the input / output valve block (300).

6. A servo cylinder system capable of self-balancing gravitational inertia according to claim 1, characterized in that, The high-pressure filter (510) is located upstream of the main oil supply channel. The oil inlet of the high-pressure filter (510) is connected to the external system pressure oil interface of the valve block, and the oil outlet of the high-pressure filter (510) is directly connected to the bottom inlet of the balance chamber pressure reducing valve (520). A bypass back pressure check valve is connected in parallel at both ends of the high-pressure filter (510). When the filter element is blocked or the pressure difference between the inlet and outlet exceeds the limit, the bypass back pressure check valve opens, and the oil is directly supplied to the rear end through the bypass channel, which effectively avoids system oil interruption and shutdown, and ensures the continuity and stability of the hydraulic circuit oil supply.

7. A servo cylinder system capable of self-balancing gravitational inertia according to claim 1, characterized in that, The balance chamber input pressure sensor (540) is connected to the oil circuit on the inlet side of the balance chamber pressure reducing valve (520) through a diversion channel, and collects the oil supply pressure parameters at the inlet front end of the balance chamber pressure reducing valve (520) in real time.

8. A servo cylinder system capable of self-balancing gravitational inertia according to claim 1, characterized in that, The accumulator (550) in the balance chamber is installed on the inlet side of the pressure reducing valve (520) in the balance chamber through the built-in diversion channel of the valve block to buffer the oil impact and stabilize the oil supply pressure at the inlet of the pressure reducing valve.

9. A servo cylinder system capable of self-balancing gravitational inertia according to claim 1, characterized in that, The balance chamber pressure reducing valve (520) is integrated and installed on the valve body surface of the balance servo valve block (500). The inlet end is connected to the upstream filtered pressure oil, and the outlet end is connected to the oil inlet of the downstream balance chamber servo valve (530).

10. A control method for a self-balancing servo cylinder system, used in the self-balancing servo cylinder system of claim 1, characterized in that... Includes the following steps: Step 1: System startup preparation: After being filtered by the high-pressure filter (510) of the balance servo valve block (500), the high-pressure oil is reduced by the pressure-reducing valve (450) and then provides the pilot oil source for the actuation servo valve (230); the balance chamber input pressure sensor (540) detects the system oil supply pressure in real time, and outputs an electrical start signal when the pressure reaches the target, and the system enters the standby state; Step 2: Gradual voltage ramp-up startup of the system: When the output shut-off solenoid valve (320) on the input / output valve block (300) is energized and turned on, the input pressure sensor (331) collects the outlet pressure of the input proportional pressure reducing valve (310) in real time and forms a closed-loop feedback, controlling the input proportional pressure reducing valve (310) to achieve stepless smooth pressure increase from zero pressure, low pressure to high pressure, providing a stable and progressive pressure oil source for the back-end test circuit; Step 3: Dynamic control of the hydraulic cylinder's ascent: When the actuation servo valve (230) is switched on, pressure oil is input to port A of the actuation cylinder (100), driving the actuation cylinder (100) to extend and achieve load lifting; the balance chamber servo valve (530) is opened synchronously to replenish oil to the balance chamber of the balance cylinder body (120) to compensate for the change in lifting volume; the cylinder chamber pressure is collected in real time by the upper chamber pressure sensor (210) and the lower chamber pressure sensor (220), and the opening degree of the actuation servo valve (230) is adjusted in a closed loop to maintain stable lifting pressure; Step 4: Lifting and lowering damping control: The actuation servo valve (230) reverses direction, and the pressure oil is input into the rod chamber of port B of the actuation cylinder (100), driving the cylinder to retract and descend; the balance chamber servo valve (530) synchronously controls the return oil of the balance cylinder body (120) to throttle and regulate it, forming controllable hydraulic damping inside the balance chamber to counteract the load inertia; at the same time, the balance chamber output pressure sensor (420) collects the balance chamber pressure in real time, and corrects the flow of the balance chamber servo valve (530) in a closed loop to ensure that the descent process is smooth and without surging. Step 5: Safety Protection During the up-and-down movement of the actuating cylinder, the output pressure sensor (321) monitors the inlet pressure of the actuating servo valve (230) in real time. When an overload or abnormal pressure is detected, the output shut-off solenoid valve (320) quickly cuts off the main oil supply circuit. At the same time, the input proportional pressure reducing valve (310) receives the signal and gradually reduces the pressure to zero, achieving a safe shutdown without impact.

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