A CAN bus load-sensitive control double-sided multi-cylinder synchronous hydraulic jacking system and method

Abstract

The application discloses a CAN bus load-sensitive control double-side multi-cylinder synchronous hydraulic jacking system and method, and is used for solving the problems of poor multi-cylinder synchronous precision, high energy consumption, weak anti-unbalance load capacity and insufficient reliability. The system integrates CAN bus digital communication and load-sensitive hydraulic control technology, and a main controller is connected with a load-sensitive valve and various sensors through a CAN bus to form a closed loop control. The method comprises the following steps: a controller drives a system to make double cylinders act, real-time collection of displacement and pressure signals and feedback, and then dynamic adjustment of load-sensitive valve current to change flow or adjustment of balance valve pilot current to change oil return back pressure according to displacement difference and working conditions, so that high-precision synchronization is realized; and when the main system fails, an emergency unit can be started to drive the oil cylinder to a safe position. The application has the advantages of high synchronous precision, strong anti-unbalance load capacity, high energy saving and efficiency and high reliability.

Description

Technical Field

[0001] This invention relates to the field of hydraulic control technology for engineering machinery, specifically to a CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic jacking system and method for lifting large equipment. Background Technology

[0002] In equipment installation and jacking operations in fields such as engineering machinery, bridges, thermal power, nuclear power, and construction, multi-cylinder synchronous hydraulic systems are often required to achieve smooth and precise jacking of large-tonnage components. Traditional synchronous hydraulic jacking systems mostly use fixed displacement pumps in conjunction with flow divider / combiner valves or analog electro-hydraulic proportional valves to achieve synchronous control. These systems have the following significant drawbacks:

[0003] 1. Poor synchronization control accuracy and weak resistance to off-center load: Traditional valves are easily affected by uneven load, friction differences and inconsistent leakage. Under off-center load conditions, the synchronization error is large, which can easily lead to tilting and jamming of the lifted components.

[0004] 2. High energy consumption and severe system overheating: The fixed displacement pump system often has a large amount of overflow loss, which is converted into heat energy, resulting in increased oil temperature and affecting system stability and component life.

[0005] 3. Complex wiring and poor anti-interference capability: Systems based on analog signals require a large number of independent cables to connect sensors and valves, which makes wiring cumbersome and susceptible to electromagnetic interference over long distances, resulting in distortion of control signals.

[0006] 4. Insufficient independent adjustment capability of multiple cylinders and low level of intelligence: It is difficult to make independent and real-time fine adjustment of the flow of each cylinder, lacks safety mechanisms such as automatic correction and overload protection, slow response, and unsatisfactory collaborative control effect.

[0007] To overcome the aforementioned shortcomings, existing technologies have employed a combination of load-sensitive pumps and electro-proportional valves. While this has improved energy consumption to some extent, it still falls short in terms of multi-cylinder coordinated control, signal transmission reliability, and dynamic synchronization accuracy. Therefore, there is an urgent need for a hydraulic jacking system that can simultaneously meet the requirements of high-precision synchronization, strong resistance to off-center loads, high efficiency and energy saving, and high reliability. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic jacking system and method that has high synchronization accuracy, strong anti-eccentric load capability, energy saving and high efficiency and high reliability, in view of the above-mentioned defects of the prior art.

[0009] The technical solution adopted by this invention to solve its technical problem is: to construct a CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic jacking system, the core of which is to integrate CAN bus digital communication technology and load-sensitive hydraulic control technology to realize distributed, intelligent closed-loop synchronous control.

[0010] According to one aspect of the present invention, a CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic lifting system is provided, characterized in that it includes: an oil tank, a hydraulic power unit, a main control valve group, a pilot control and emergency unit, an actuator, a sensor detection unit, and a main controller;

[0011] The hydraulic power unit includes a motor, a load-sensitive pump driven by the motor, and a check valve connected to the outlet pipeline of the load-sensitive pump.

[0012] The main control valve group includes a CAN bus load-sensitive valve and an emergency switching valve; the oil inlet of the CAN bus load-sensitive valve is connected to the oil outlet of the hydraulic power unit, and its return port is connected to the oil tank; the oil port of the emergency switching valve is connected to the working oil port of the CAN bus load-sensitive valve, the pilot control and emergency unit, and the actuator, respectively.

[0013] The actuator includes a left hydraulic cylinder and a right hydraulic cylinder. The rodless chamber and the rod chamber of the left hydraulic cylinder and the right hydraulic cylinder are both connected to the main control valve group through the emergency switching valve via an oil circuit.

[0014] The sensor detection unit includes a left displacement sensor for detecting the displacement of the left hydraulic cylinder, a right displacement sensor for detecting the displacement of the right hydraulic cylinder, a left pressure sensor for detecting the pressure in both chambers of the left hydraulic cylinder, and a right pressure sensor for detecting the pressure in both chambers of the right hydraulic cylinder.

[0015] The signal output terminals of the left displacement sensor, the right displacement sensor, the left pressure sensor, and the right pressure sensor, as well as the control terminal of the CAN bus load-sensitive valve, are all connected to the main controller, which communicates with the above components via the CAN bus.

[0016] Furthermore, the system also includes an independent circulating cooling unit, an oil suction filter, a return oil filter, and a temperature sensor installed on the oil tank; the oil inlet of the load-sensitive pump is connected to the oil tank through the oil suction filter; the oil return port of the pilot control and emergency unit is connected to the oil tank through the return oil filter; the temperature sensor is used to monitor the oil temperature and feed it back to the controller to control the start and stop of the independent circulating cooling unit.

[0017] Furthermore, the independent circulating heat dissipation unit includes a heat dissipation oil circuit, a heat dissipation hydraulic pump and heat sinks disposed on the heat dissipation oil circuit, and a fan for dissipating heat from the heat sinks; the input end of the heat dissipation oil circuit is connected to the oil tank through a heat dissipation suction oil filter, and the output end is connected to the oil tank through a heat dissipation return oil filter.

[0018] Furthermore, the CAN bus load-sensitive valve is at least a two-way load-sensitive electro-hydraulic proportional multi-way valve, including a first valve unit and a second valve unit.

[0019] The first valve unit is a first three-position four-way electro-hydraulic proportional directional valve, controlled by electromagnets Y9a and Y9b, used to control the movement of the left-side cylinder;

[0020] The second valve unit is a second three-position four-way electro-hydraulic proportional directional valve, controlled by electromagnets Y10a and Y10b, used to control the movement of the right-side cylinder.

[0021] Furthermore, the emergency switching valve includes multiple sets of two-position two-way solenoid valves, each set corresponding to a hydraulic cylinder control circuit;

[0022] Among them, the inlets of the first set of solenoid valves Y11 and Y12 are connected in parallel and then connected to one working port of the first valve unit. Their outlets are connected to the inlet of the first balance valve, and the outlet of the first balance valve is connected to the rodless chamber of the left cylinder.

[0023] The inlets of the second set of solenoid valves Y13 and Y14 are connected in parallel and then connected to another working port of the first valve unit. Their outlets are connected to the rod chamber of the left cylinder.

[0024] The inlets of the third set of solenoid valves Y15 and Y16 are connected in parallel and then connected to one of the working ports of the second combined valve unit. Their outlets are connected to the inlet of the second balance valve, and the outlet of the second balance valve is connected to the rodless chamber of the right-side cylinder.

[0025] The inlets of the fourth set of solenoid valves Y17 and Y18 are connected in parallel and then connected to another working port of the second combined valve unit. Their outlets are connected to the rod chamber of the right-side cylinder.

[0026] Furthermore, the pilot control and emergency response unit includes:

[0027] A high-capacity pilot pump, the oil inlet of which is connected to the oil tank;

[0028] The pilot control valve has its inlet connected to the outlet of the high-capacity pilot pump, and its output oil circuit connected to the pilot control terminals Y19a and Y19b of the first balance valve and the second balance valve, for controlling the opening of the first balance valve and the second balance valve.

[0029] An emergency motor and an emergency pump driven by it, wherein the outlet of the emergency pump is connected to the inlet of an emergency control valve via a high-pressure filter;

[0030] The emergency control valve is provided with multiple working oil ports, which are respectively connected to the emergency inlets of each group of solenoid valves in the emergency switching valve, that is, respectively connected to the inlets of solenoid valves Y12, Y14, Y16 and Y18.

[0031] Furthermore, the main controller is configured to execute the following control logic: receive feedback signals from the left displacement sensor, the right displacement sensor, the left pressure sensor, and the right pressure sensor; send control commands to the CAN bus load-sensitive valve via the CAN bus; dynamically adjust the proportional electromagnet current of each valve unit to change the valve opening, thereby independently adjusting the flow rate entering the left and right cylinders to achieve displacement synchronization and pressure balance.

[0032] Furthermore, the pilot control valve is also connected to an auxiliary control oil circuit for controlling the auxiliary oil cylinder connected to the lifting beam.

[0033] According to another aspect of the present invention, this application also provides a control method based on the said system, comprising the following steps:

[0034] S1: System power-on initialization, the main controller establishes communication with the CAN bus load sensitive valve, the left displacement sensor, the right displacement sensor, the left pressure sensor, and the right pressure sensor via the CAN bus;

[0035] S2: The main controller receives a lifting command, which includes the target displacement, velocity, and direction;

[0036] S3: Start the motor and the load-sensitive pump. The main controller sends a control command to the CAN bus load-sensitive valve via the CAN bus to drive the left and right oil cylinders to start operating.

[0037] S4: During the operation of the hydraulic cylinder, the left displacement sensor, the right displacement sensor, the left pressure sensor and the right pressure sensor collect the displacement signal and pressure signal of each hydraulic cylinder in real time, and feed them back to the main controller through the CAN bus;

[0038] S5: The main controller compares the real-time displacement of each cylinder with the target displacement and calculates the displacement difference between each cylinder;

[0039] S6: The main controller performs synchronous control based on the displacement difference and the working state of the hydraulic cylinder.

[0040] S6.1 In the case of cylinder extension or cylinder retraction under no-load conditions, if the displacement is asynchronous, the main controller adjusts the proportional electromagnet current value of the corresponding valve unit in the CAN bus load-sensitive valve through the CAN bus to change the flow rate entering the leading or lagging cylinder.

[0041] S6.2 Under heavy-load cylinder compression conditions, if displacement asynchrony occurs, the main controller adjusts the pilot control current value of the first balance valve or the second balance valve to change the back pressure of the corresponding oil cylinder return circuit.

[0042] S7: Repeat steps S4-S6 until all cylinders reach the target displacement to complete the lifting or lowering operation.

[0043] Furthermore, in the event of a failure of the main hydraulic system, the following steps are performed:

[0044] The emergency motor is started to drive the emergency pump;

[0045] The emergency control valve is energized to switch the oil circuit, and the emergency pressure oil is led to the corresponding emergency inlet in the emergency switching valve.

[0046] The solenoid valve connected to the emergency oil circuit in the emergency switching valve is controlled to operate, so that the emergency pressure oil bypasses the CAN bus load sensitive valve and directly enters the rodless or rod chamber of the left or right oil cylinder through the first or second balance valve, driving the oil cylinder to move to a safe position.

[0047] The advantages of this invention compared to the prior art are:

[0048] 1. High synchronization control accuracy and strong resistance to off-center loads: High-speed real-time communication between the controller, valves, and sensors is achieved using a CAN bus. Combined with displacement and pressure dual closed-loop feedback and cross-coupling control algorithms, synchronization deviations can be dynamically eliminated. The pressure compensation function of the CAN bus load-sensitive valve makes the flow rate of each cylinder independently controllable, unaffected by load fluctuations, greatly improving synchronization stability under asymmetrical loads.

[0049] 2. High efficiency and energy saving: The combination of load-sensitive pump and CAN bus load-sensitive valve enables the system output pressure and flow to accurately match the real-time load demand, fundamentally avoiding the large flow overflow loss of traditional fixed displacement pump systems and significantly reducing energy consumption and system heat generation.

[0050] 3. High reliability and good anti-interference: The system adopts a fully digital CAN bus communication, replacing a large number of analog signal lines, simplifying wiring, and using heavy-duty connectors for easy installation and disassembly. It also significantly improves the electromagnetic interference resistance of signal transmission. The distributed control architecture further enhances system reliability.

[0051] 4. High level of intelligence and safety: The system features comprehensive automatic correction, overload protection, and off-center load warning functions. When displacement or pressure deviation exceeds the set threshold, the system can automatically adjust or issue an alarm. An independent emergency unit ensures safe equipment recovery in the event of a main system failure, and multiple protection mechanisms guarantee operational safety.

[0052] 5. Fast response speed and good collaborative control effect: The digital bus has low transmission delay and rapid control command issuance and status feedback, making the collaborative control between multiple cylinders more timely and accurate, and improving the dynamic performance of the system. Attached Figure Description

[0053] Figure 1 This is a schematic diagram of the hydraulic system according to an embodiment of the present invention.

[0054] Figure 2 This is a schematic diagram of the hydraulic system in the case of cylinder extension with pin shaft in an embodiment of the present invention.

[0055] Figure 3 This is a schematic diagram of the hydraulic system in the cylinder retraction mode of the present invention embodiment.

[0056] Figure 4 This is a schematic diagram illustrating the principle of the hydraulic system under no-load or heavy-load lifting conditions according to an embodiment of the present invention.

[0057] Figure 5 This is a schematic diagram illustrating the principle of the hydraulic system in the unloaded or heavily loaded descent condition according to an embodiment of the present invention.

[0058] Figure 6 This is a schematic diagram illustrating the principle of the hydraulic system in emergency cylinder extension mode according to an embodiment of the present invention.

[0059] Figure 7 This is a schematic diagram illustrating the principle of the hydraulic system in emergency cylinder retraction mode according to an embodiment of the present invention.

[0060] In the diagram: 1-Suction oil filter, 2-Independent circulating cooling unit, 22-Cooling hydraulic pump, 23-Heat sink, 24-Fan, 25-Cooling suction oil filter, 26-Cooling return oil filter, 3-Temperature sensor, 4-Return oil filter, 5-Motor, 6-Load-sensitive pump, 7-High pressure pilot pump, 8-Pilot control valve, 9-Emergency motor, 10-Emergency pump, 11-High pressure filter, 12-Emergency control valve, 13-CAN bus load-sensitive valve, 14-Emergency switching valve, 15a-First balancing valve, 15b-Second balancing valve, 16-1 Left pressure sensor, 16-2 Right pressure sensor, 17-1 Left displacement sensor, 17-2 Right displacement sensor, 18-1 Left cylinder, 18-2 Right cylinder, 100-Oil tank. Detailed Implementation

[0061] To make the objectives, technical solutions, and advantages of the present invention clearer, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0062] System overall structure and connection relationship

[0063] Reference Figure 1 The present invention provides a CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic lifting system, the specific implementation of which is as follows.

[0064] The system mainly includes an oil tank 100, a hydraulic power unit, a main control valve group, a pilot control and emergency unit, an actuator, a sensor detection unit, and a main controller.

[0065] The oil tank 100 serves as the foundation for oil storage and heat dissipation in the entire hydraulic system. An oil suction filter 1 and a return oil filter 4 are installed on the oil tank 100. The oil suction filter 1 is installed at the front end of the oil suction port of the hydraulic power unit to filter the oil entering the system, protecting the hydraulic pump and precision valves. The return oil filter 4 is installed in the system's return oil circuit to filter the system's return oil, keeping the oil clean. The oil tank 100 also integrates an independent circulating heat dissipation unit 2, which includes a heat dissipation oil circuit, a heat dissipation hydraulic pump 22 and heat sink 23 located on the heat dissipation oil circuit, and a fan 24 for forced cooling of the heat sink 23. The input end of the heat dissipation oil circuit is connected to the oil tank 100 through a heat dissipation oil suction filter 25, and the output end is connected to the oil tank 100 through a heat dissipation return oil filter 26. A temperature sensor 3 monitors the oil temperature inside the oil tank 100 in real time and feeds the signal back to the main controller. When the oil temperature is higher than the set value, the main controller starts the independent circulating heat dissipation unit 2 for cooling; when the oil temperature is lower than the set value, the heat dissipation unit stops working, thereby realizing automatic control of oil temperature and ensuring continuous and stable operation of the system.

[0066] The hydraulic power unit is the main pressure and flow source of the system, including a motor 5 and a load-sensitive pump 6 driven by the motor 5. The oil inlet of the load-sensitive pump 6 is connected to the oil tank 100 through the suction filter 1, and a one-way valve is connected to its oil outlet pipeline to prevent backflow of pressurized oil and protect the pump body. The core feature of the load-sensitive pump 6 is that it has a load-sensitive feedback interface (LS port), which is connected to the load-sensitive feedback oil circuit of the main control valve group through a pipeline, and can sense the highest working pressure of the actuator in the system in real time. Based on this feedback pressure, the load-sensitive pump 6 automatically adjusts its swashplate angle to output only the flow rate exactly required by the actuator and a pressure slightly higher than the maximum load pressure, thereby achieving "on-demand oil supply", avoiding the large flow overflow loss of traditional fixed displacement pump systems from the source, and significantly reducing system energy consumption and heat generation.

[0067] The main control valve group is the core control component of this invention, mainly including a CAN bus load-sensitive valve 13 and an emergency switching valve 14. The inlet P of the CAN bus load-sensitive valve 13 is connected to the outlet of the hydraulic power unit (i.e., the pressure oil circuit after the load-sensitive pump 6 via the check valve), and its return port T is connected to the oil tank 100. This valve is an electro-hydraulic proportional multi-way valve with integrated CAN bus communication function. In this embodiment, it is at least a two-way load-sensitive electro-hydraulic proportional valve, specifically including a first valve unit and a second valve unit. The first valve unit is a first three-position four-way electro-hydraulic proportional directional valve, controlled by proportional solenoids Y9a and Y9b, typically used to control the movement of the left cylinder 18-1; the second valve unit is a second three-position four-way electro-hydraulic proportional directional valve, controlled by proportional solenoids Y10a and Y10b, typically used to control the movement of the right cylinder 18-2. Each valve integrates a pressure compensator to ensure a constant pressure difference across the valve port. This allows the flow rate through the valve to be precisely proportional to the input current of the proportional electromagnet (i.e., the valve opening), unaffected by load pressure fluctuations. This is crucial for achieving high-precision flow distribution and resistance to off-center loads.

[0068] The oil ports of the emergency switching valve 14 are connected to the working oil port of the CAN bus load-sensitive valve 13, the pilot control and emergency unit, and the actuator, respectively. Specifically, the emergency switching valve 14 consists of multiple sets of two-position two-way solenoid valves, each set corresponding to a cylinder control oil circuit, used for switching oil circuits between the main system and the emergency system. Taking the control of dual cylinders on both sides as an example, it includes four sets of solenoid valves: the inlets of the first set (Y11, Y12) are connected in parallel to one working oil port (port A or port B) of the first valve unit, and their outlets are connected to the inlet of the first balance valve 15a. The outlet of the first balance valve 15a is connected to the rodless chamber of the left cylinder 18-1. The inlets of the second set (Y13, Y14) are connected in parallel to the other working oil port of the first valve unit, and their outlets are connected to the rod chamber of the left cylinder 18-1. The inlets of the third group (Y15, Y16) are connected in parallel to one working port of the second valve unit, and their outlets are connected to the inlet of the second balance valve 15b. The outlet of the second balance valve 15b is connected to the rodless chamber of the right-side cylinder 18-2. The inlets of the fourth group (Y17, Y18) are connected in parallel to the other working port of the second valve unit, and their outlets are connected to the rod chamber of the right-side cylinder 18-2. The inlets of the even-numbered solenoid valves (Y12, Y14, Y16, Y18) in each group are connected to the emergency oil circuit as emergency inlets.

[0069] The actuator includes a symmetrically arranged left-side hydraulic cylinder 18-1 and a right-side hydraulic cylinder 18-2. The rodless and rod-side chambers of both the left-side and right-side hydraulic cylinders 18-1 and 18-2 are connected to the main control valve group via an emergency switching valve 14 through an oil circuit. Balance valves 15a and 15b are connected in series in the return oil circuit of the rodless chamber of the hydraulic cylinders. They are used to generate back pressure during cylinder descent, balance the load, prevent stalling, and lock the cylinders in case of system pressure loss, thus providing safety protection.

[0070] The pilot control and emergency unit includes a high-pressure pilot pump 7, a pilot control valve 8, an emergency motor 9, an emergency pump 10, a high-pressure filter 11, and an emergency control valve 12. The inlet of the high-pressure pilot pump 7 is connected to the oil tank 100, and its outlet supplies oil to the pilot control valve 8. The output oil circuit of the pilot control valve 8 is connected to the pilot control terminals (Y19a, Y19b) of the first balance valve 15a and the second balance valve 15b for remote control of the opening of the balance valves. In addition, the pilot control valve 8 can also be connected to an auxiliary control oil circuit to control the auxiliary cylinder 18-3 connected to the lifting beam, enabling the pushing and pulling auxiliary action of the lifting beam and reducing manual labor intensity. The emergency unit is powered by the emergency motor 9 driving the emergency pump 10. The oil output from the emergency pump 10 is filtered by the high-pressure filter 11 before entering the emergency control valve 12. The emergency control valve 12 has multiple working ports, which are respectively connected to the emergency inlets of each group of solenoid valves in the emergency switching valve 14 (i.e., the inlets of Y12, Y14, Y16, and Y18). This unit can be activated when the main system fails.

[0071] The sensor detection unit includes a left displacement sensor 17-1, a right displacement sensor 17-2, a left pressure sensor 16-1, and a right pressure sensor 16-2. The displacement sensors detect the displacement of the corresponding hydraulic cylinder piston rod in real time, and the pressure sensors detect the pressure in the rodless and rod-side chambers of the corresponding hydraulic cylinder in real time. All sensors support CAN bus output.

[0072] The main controller is the "brain" of the system. It establishes real-time, high-speed, and interference-resistant digital communication with the CAN bus load-sensitive valve 13, each displacement sensor, and each pressure sensor via the CAN bus. The main controller receives sensor feedback signals and performs calculations according to preset control algorithms (such as PID, cross-coupling control, etc.). It then sends current commands to the proportional electromagnet of the CAN bus load-sensitive valve 13 via the CAN bus to dynamically adjust the valve opening, thereby precisely controlling the flow rate into each cylinder and achieving high-precision synchronous motion.

[0073] Detailed Explanation of System Workflow and Typical Operating Condition Control Paths

[0074] The following sections, using several typical operating conditions, elaborate on the workflow and control path of the system of this invention.

[0075] Typical operating condition 1: Installing the pin (single-cylinder precision micro-motion control)

[0076] Reference Appendix Figure 2 - Appendix Figure 3 During initial equipment assembly, the hydraulic cylinder hinge point needs to be aligned and connected to the lifting beam using pins. This operation requires high-precision micro-motion control of the extension and retraction of a single hydraulic cylinder.

[0077] Left cylinder extension: Start motor 5 drives load-sensitive pump 6 to supply oil. The main controller sends a command to CAN bus load-sensitive valve 13 via CAN bus, energizing electromagnet Y9a (de-energizing Y9b), and the first valve unit operates in the left position. Simultaneously, it energizes Y11 in emergency switching valve 14 (Y12, Y13, Y14, etc. are in non-emergency state). The pressure oil path is: load-sensitive pump 6 → check valve → CAN bus load-sensitive valve 13, first valve left position → emergency switching valve 14, Y11 → first balance valve 15a → rodless chamber of left cylinder 18-1. The return oil path is: rod chamber of left cylinder 18-1 → emergency switching valve 14, Y13 → CAN bus load-sensitive valve 13, first valve left position → oil tank 100. By precisely adjusting the current value of Y9a by the main controller, the flow rate entering the rodless chamber of the left cylinder can be steplessly controlled, achieving millimeter-level precise extension of the piston rod.

[0078] Left cylinder retraction: The main controller commands Y9b to be energized (Y9a de-energized), the first interlocking valve unit operates in the right position, and Y13 is energized. Pressurized oil enters the rod chamber of the left cylinder, pushing the piston rod to retract. Return oil flows from the rodless chamber of the left cylinder, through the first balance valve 15a, and then, under the action of reverse oil flow, opens Y11 and the first interlocking valve unit in the right position, flowing back to the oil tank. The single-acting control principle of the right cylinder is the same; only the second interlocking valve unit (Y10a / Y10b) of the CAN bus load-sensitive valve 13 and the corresponding Y15 / Y17 of the emergency switching valve 14 need to be operated.

[0079] Typical operating conditions two and three: lifting / lowering under no-load or heavy-load conditions (dual-cylinder synchronous operation)

[0080] Reference Appendix Figure 4 - Appendix Figure 5 In this working condition, both hydraulic cylinders operate simultaneously to perform lifting or lowering operations.

[0081] Synchronous lifting (extension) of dual-cylinder system: The main controller simultaneously energizes Y9a and Y10a, causing both valve units of the CAN bus load-sensitive valve 13 to operate in the left position. Pressure oil is divided into two paths: one path passes through the first left position, Y11, and the first balance valve 15a into the rodless chamber of the left cylinder; the other path passes through the second left position, Y15, and the second balance valve 15b into the rodless chamber of the right cylinder. Return oil from the rod chambers of both cylinders passes through Y13 and Y17 respectively, returning to the oil tank through their respective valve positions. The LS port of the load-sensitive pump 6 senses the higher pressure in the rodless chambers of both cylinders and adjusts the pump displacement accordingly, supplying oil as needed. The pressure compensator inside the CAN bus load-sensitive valve 13 ensures that the flow rate entering the left and right cylinders is only related to the opening of their respective valve cores (i.e., the current setting of Y9a and Y10a), thus ensuring that the flow rate is basically consistent under ideal conditions, achieving initial synchronization.

[0082] Synchronous descent of both cylinders (cylinder retraction): The main controller commands Y9b and Y10b to be energized, causing the two-way valve unit to operate in the right position. Pressure oil enters the rod chambers of the left and right cylinders in two separate paths. The return oil from the rodless chambers of the two cylinders, under the weight of the cylinders and the load, forms a certain pressure, pushing open the balance valves 15a and 15b on their respective circuits, and returning to the oil tank via Y11, Y15, and the valve assembly. During this process, the balance valves provide stable return oil back pressure, preventing the cylinders from stalling or vibrating during descent, ensuring a smooth descent. At this time, the throttle speed control valve in the hydraulic control valve (balance valve) can initially adjust the return oil flow rate.

[0083] Typical operating condition 4: High-precision synchronous closed-loop control of dual-side dual-cylinder system

[0084] The above-mentioned lifting / lowering is an open-loop synchronization. To achieve high-precision synchronization, the system enters a closed-loop control mode. The main controller acquires signals from the left and right displacement sensors 17-1 and 17-2 in real time and calculates the real-time displacement difference (synchronization error) between the two cylinders.

[0085] Correction under cylinder extension or cylinder retraction conditions: If the displacement of the left cylinder is detected to be greater than that of the right cylinder (i.e., the left cylinder is ahead), the main controller executes a synchronous correction algorithm (a cross-coupled PID algorithm can be used). It dynamically adjusts the proportional electromagnet current value of the valve unit corresponding to the CAN bus load-sensitive valve 13 via the CAN bus. For example, it reduces the current of the left cylinder inlet valve Y9a to decrease its valve opening, and / or increases the current of the right cylinder inlet valve Y10a to increase its valve opening, thereby dynamically adjusting the flow rate into the two cylinders, reducing the displacement difference until it reaches zero.

[0086] Correction under heavy-load cylinder retraction conditions: This condition is quite special. Due to the load's gravity, the cylinder's descent is mainly controlled by the back pressure of the return oil circuit. If the left cylinder's displacement is greater than the right cylinder's, the main controller can adjust the pilot control valve 8 to change the pilot control current (Y19a) of the first balance valve 15a, increasing its opening to reduce the return oil back pressure of the left cylinder, and / or decrease the opening of the second balance valve 15b (Y19b) to increase the return oil back pressure of the right cylinder, thereby adjusting the descent speed of the two cylinders to achieve synchronization. Under this condition, care must be taken to prevent cavitation in the rod chamber; if necessary, the current of the inlet valves (Y9b / Y10b) should be adjusted accordingly.

[0087] Typical Operating Condition Six: Emergency Control

[0088] Reference Appendix Figure 6 - Appendix Figure 7 When the main system (motor 5 or load-sensitive pump 6 fails) or power is lost, the emergency unit is activated.

[0089] Emergency cylinder extension: The emergency motor 9 is activated to drive the emergency pump 10. The corresponding solenoids (e.g., Y7, Y8) of the emergency control valve 12 are energized, switching the oil circuit. Simultaneously, the emergency channel solenoid valves (Y12, Y14, Y16, Y18) in the emergency switching valve 14 are energized. The emergency pressure oil path is: emergency pump 10 → high-pressure filter 11 → emergency control valve 12 → Y12 → first balance valve 15a → left cylinder rodless chamber; and → Y16 → second balance valve 15b → right cylinder rodless chamber. Return oil flows from the rod chamber of the cylinder, through Y14 / Y18, and the emergency control valve 12 back to the oil tank. This process completely bypasses the failed main pump and the CAN bus load-sensitive valve 13, using a simple on / off valve control to move the cylinder to a safe position.

[0090] Typical Operating Condition 7: Intelligent Heat Dissipation Control

[0091] During system operation, temperature sensor 3 continuously monitors the oil temperature. When the main controller determines that the oil temperature is higher than the set upper limit, it automatically starts the independent circulating cooling unit 2, regardless of whether the main hydraulic system is working. The cooling hydraulic pump 22 draws oil from the oil tank 100 through the cooling suction filter 25. The pumped oil flows through the heat sink 23, and under the forced cooling of the fan 24, the oil temperature decreases. Then, it returns to the oil tank 100 through the cooling return filter 26, forming an independent cooling cycle that effectively controls the oil temperature of the entire system.

[0092] Summary of Control Methods and Strategies

[0093] In summary, the core of the control method of this invention lies in closed-loop synchronous control. The main controller acquires the displacement and pressure information of each cylinder in real time via the CAN bus. During normal lifting operations, it compares the target displacement with the real-time displacement and calculates the displacement difference between cylinders. Based on the operating conditions (cylinder extension / no-load cylinder retraction / heavy-load cylinder retraction), the main controller selects the adjustment target: in most cases, it dynamically adjusts the proportional electromagnet current of the valve unit corresponding to the CAN bus load-sensitive valve 13 via the CAN bus to change the valve opening and adjust the flow distribution; during heavy-load descent, it adjusts the output of the pilot control valve 8 to change the pilot pressure of the first balance valve 15a and the second balance valve 15b, thereby adjusting the return oil back pressure to achieve synchronization. This control method, with displacement closed-loop as the main component and pressure closed-loop as a supplement (for off-center load protection and pressure balancing), combined with specific operating condition strategies, ensures that the system can achieve high-precision synchronization under various load conditions. Simultaneously, the system also includes a complete emergency control method to ensure equipment safety in the event of a main system failure.

[0094] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. The present invention and its embodiments have been described above, and this description is not restrictive. The figures shown are only one embodiment of the present invention, and the actual structure is not limited thereto. In conclusion, if those skilled in the art are inspired by this description and design similar structural methods and embodiments without departing from the inventive spirit of the present invention, they should all fall within the scope of protection of the present invention.

Claims

1. A CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic jacking system, characterized in that, include: Oil tank (100), hydraulic power unit, main control valve group, pilot control and emergency unit, actuator, sensor detection unit and main controller; The hydraulic power unit includes a motor (5), a load-sensitive pump (6) driven by the motor (5), and a check valve connected to the outlet pipeline of the load-sensitive pump (6); The main control valve group includes a CAN bus load sensitive valve (13) and an emergency switching valve (14); the oil inlet of the CAN bus load sensitive valve (13) is connected to the oil outlet of the hydraulic power unit, and its return port is connected to the oil tank (100); the oil port of the emergency switching valve (14) is connected to the working oil port of the CAN bus load sensitive valve (13), the pilot control and emergency unit, and the actuator, respectively. The actuator includes a left cylinder (18-1) and a right cylinder (18-2). The rodless chamber and the rod chamber of the left cylinder (18-1) and the right cylinder (18-2) are connected to the main control valve group through the emergency switching valve (14) via oil circuits. The sensor detection unit includes a left displacement sensor (17-1) for detecting the displacement of the left cylinder (18-1), a right displacement sensor (17-2) for detecting the displacement of the right cylinder (18-2), a left pressure sensor (16-1) for detecting the pressure in both chambers of the left cylinder (18-1), and a right pressure sensor (16-2) for detecting the pressure in both chambers of the right cylinder (18-2). The signal output terminals of the left displacement sensor (17-1), the right displacement sensor (17-2), the left pressure sensor (16-1), and the right pressure sensor (16-2), as well as the control terminal of the CAN bus load sensitive valve (13), are all connected to the main controller. The main controller communicates with the above components via the CAN bus.

2. The CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic jacking system according to claim 1, characterized in that, The system also includes an independent circulating heat dissipation unit (2), an oil suction filter (1), a return oil filter (4), and a temperature sensor (3) installed on the oil tank (100); the oil inlet of the load-sensitive pump (6) is connected to the oil tank (100) through the oil suction filter (1); the oil return port of the pilot control and emergency unit is connected to the oil tank (100) through the return oil filter (4); the temperature sensor (3) is used to monitor the oil temperature and feed it back to the controller to control the start and stop of the independent circulating heat dissipation unit (2).

3. The CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic jacking system according to claim 2, characterized in that, The independent circulating heat dissipation unit (2) includes a heat dissipation oil circuit, a heat dissipation hydraulic pump (22) and a heat sink (23) provided on the heat dissipation oil circuit, and a fan (24) for dissipating heat from the heat sink (23); the input end of the heat dissipation oil circuit is connected to the oil tank (100) through a heat dissipation oil suction filter (25), and the output end is connected to the oil tank (100) through a heat dissipation oil return filter (26).

4. The CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic jacking system according to claim 1, characterized in that, The CAN bus load-sensitive valve (13) is a load-sensitive electro-hydraulic proportional multi-way valve with at least two valves, including a first valve unit and a second valve unit. The first valve unit is a first three-position four-way electro-hydraulic proportional directional valve, controlled by electromagnets Y9a and Y9b, used to control the action of the left-side cylinder (18-1); The second valve unit is a second three-position four-way electro-hydraulic proportional directional valve, controlled by electromagnets Y10a and Y10b, used to control the action of the right-side cylinder (18-2).

5. A CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic jacking system according to claim 4, characterized in that, The emergency switching valve (14) includes multiple sets of two-position two-way solenoid valves, each set corresponding to a hydraulic cylinder control circuit; Among them, the inlets of the first set of solenoid valves Y11 and Y12 are connected in parallel and then connected to one working port of the first valve unit. Their outlets are connected to the inlet of the first balance valve (15a). The outlet of the first balance valve (15a) is connected to the rodless chamber of the left cylinder (18-1). The inlets of the second set of solenoid valves Y13 and Y14 are connected in parallel and then connected to another working port of the first valve unit. Their outlets are connected to the rod chamber of the left cylinder (18-1). The inlets of the third set of solenoid valves Y15 and Y16 are connected in parallel and then connected to one of the working ports of the second combined valve unit. Their outlets are connected to the inlet of the second balance valve (15b), and the outlet of the second balance valve (15b) is connected to the rodless chamber of the right-side cylinder (18-2). The inlets of the fourth set of solenoid valves Y17 and Y18 are connected in parallel and then connected to another working port of the second combined valve unit. Their outlets are connected to the rod chamber of the right-side cylinder (18-2).

6. A CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic jacking system according to claim 5, characterized in that, The pilot control and emergency response unit includes: A high-capacity pilot pump (7) has its inlet connected to the oil tank (100); The pilot control valve (8) has its inlet connected to the outlet of the high pilot pump (7), and its output oil circuit is connected to the pilot control terminals Y19a and Y19b of the first balance valve (15a) and the second balance valve (15b), for controlling the opening of the first balance valve (15a) and the second balance valve (15b); An emergency motor (9) and an emergency pump (10) driven therefrom, the outlet of which is connected to the inlet of an emergency control valve (12) via a high-pressure filter (11); The emergency control valve (12) is provided with multiple working oil ports, which are respectively connected to the emergency inlets of each group of solenoid valves in the emergency switching valve (14), that is, respectively connected to the inlets of solenoid valves Y12, Y14, Y16 and Y18.

7. The CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic jacking system according to claim 1, characterized in that, The main controller is configured to execute the following control logic: receive feedback signals from the left displacement sensor (17-1), the right displacement sensor (17-2), the left pressure sensor (16-1), and the right pressure sensor (16-2), send control commands to the CAN bus load sensitive valve (13) via the CAN bus, dynamically adjust the proportional electromagnet current of each valve unit to change the valve opening, thereby independently adjusting the flow rate entering the left oil cylinder (18-1) and the right oil cylinder (18-2) to achieve displacement synchronization and pressure balance.

8. A CAN bus load-sensitive control dual-side multi-cylinder synchronous hydraulic jacking system according to claim 6, characterized in that, The pilot control valve (8) is also connected to an auxiliary control oil circuit for controlling the auxiliary oil cylinder (18-3) connected to the lifting beam.

9. A control method based on the system according to any one of claims 1-8, characterized in that, Includes the following steps: S1: System power-on initialization, the main controller establishes communication with the CAN bus load sensitive valve (13), the left displacement sensor (17-1), the right displacement sensor (17-2), the left pressure sensor (16-1), and the right pressure sensor (16-2) through the CAN bus; S2: The main controller receives a lifting command, which includes the target displacement, velocity, and direction; S3: Start the motor (5) and the load-sensitive pump (6). The main controller sends a control command to the CAN bus load-sensitive valve (13) via the CAN bus to drive the left cylinder (18-1) and the right cylinder (18-2) to start operating. S4: During the operation of the hydraulic cylinder, the left displacement sensor (17-1), the right displacement sensor (17-2), the left pressure sensor (16-1), and the right pressure sensor (16-2) collect the displacement and pressure signals of each hydraulic cylinder in real time and feed them back to the main controller via the CAN bus; S5: The main controller compares the real-time displacement of each cylinder with the target displacement and calculates the displacement difference between each cylinder; S6: The main controller performs synchronous control based on the displacement difference and the working state of the hydraulic cylinder. S6.1 In the case of cylinder extension or cylinder retraction under no-load conditions, if the displacement is not synchronized, the main controller adjusts the proportional electromagnet current value of the corresponding valve unit in the CAN bus load sensitive valve (13) through the CAN bus to change the flow rate into the leading or lagging cylinder. S6.2 Under heavy-load cylinder shrinkage conditions, if displacement asynchrony occurs, the main controller adjusts the pilot control current value of the first balance valve (15a) or the second balance valve (15b) to change the back pressure of the corresponding oil cylinder return circuit. S7: Repeat steps S4-S6 until all cylinders reach the target displacement to complete the lifting or lowering operation.

10. An emergency control method based on the system of claim 6, characterized in that, When the main hydraulic system fails, perform the following steps: Start the emergency motor (9) to drive the emergency pump (10); The emergency control valve (12) is energized to switch the oil circuit, and the emergency pressure oil is led to the corresponding emergency inlet in the emergency switching valve (14); The solenoid valve connected to the emergency oil circuit in the emergency switching valve (14) is controlled to operate, so that the emergency pressure oil bypasses the CAN bus load sensitive valve (13) and directly enters the rodless or rod chamber of the left oil cylinder (18-1) or the right oil cylinder (18-2) through the first balance valve (15a) or the second balance valve (15b), driving the oil cylinder to move to a safe position.

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