Control system of hydraulic cylinder

Abstract

The invention provides a control system of a hydraulic cylinder, and belongs to the technical field of hydraulic control. The control system comprises a pump set, two control valve sets, a detection assembly and an electric control assembly. The pump set is connected with oil inlets of the two control valve sets, the two control valve sets are in one-to-one correspondence with the two hydraulic cylinders, and each control valve set in the two control valve sets is connected with a rod cavity and a rodless cavity of the corresponding hydraulic cylinder. The detection assembly is respectively connected with piston rods of the two hydraulic cylinders, and the detection assembly is configured to detect the loading force and displacement of the piston rods in the two hydraulic cylinders; the electric control assembly is electrically connected with the detection assembly and the two control valve sets. The synchronous action precision of the hydraulic cylinders can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of hydraulic control, and in particular relates to a control system of a hydraulic cylinder. Background Art

[0002] In the field of lifting, it is often encountered that at least two hydraulic cylinders are connected to the lifting device at the same time. By controlling the at least two hydraulic cylinders to move synchronously, the lifting device can be kept horizontal during movement.

[0003] In the related art, when controlling the synchronous movement of at least two hydraulic cylinders, a mechanical passive synchronization method is generally adopted. The cylinder bodies of at least two hydraulic cylinders are rigidly connected through a mechanical structure, and at the same time, the piston rods of at least two hydraulic cylinders are rigidly connected, and the rodless chambers of at least two hydraulic cylinders are interconnected, and the rod chambers of at least two hydraulic cylinders are interconnected, so that the working pressure and output force of each hydraulic cylinder are the same. In order to improve the control accuracy, at least two hydraulic cylinders are evenly spaced and arranged in a row. Then, the at least two hydraulic cylinders are controlled by a hydraulic control system. The hydraulic control system includes a pump group and a control valve group. The high-pressure oil output by the pump group enters the rodless chamber or rod chamber of each hydraulic cylinder through a pipeline through the control valve group.

[0004] However, in some working conditions, these hydraulic cylinders are far apart from each other and the load is an offset load. Since the piston rods of the hydraulic cylinders are rigidly connected together, the theoretical force and working pressure of each hydraulic cylinder are quite different, and the working pressure of the hydraulic cylinder closer to the center of gravity of the load is higher. In this way, directly connecting the hydraulic cylinders through pipelines obviously cannot make the displacement of the piston rods of each hydraulic cylinder the same and achieve synchronization. Summary of the invention

[0005] The disclosed embodiment provides a control system of a hydraulic cylinder, which can lift an offset load. The technical solution is as follows:

[0006] The disclosed embodiment provides a control system of a hydraulic cylinder, which is used to control the synchronous movement of at least two hydraulic cylinders, and the control system includes a pump group, at least two control valve groups, a detection component and an electronic control component; the pump group is connected to the oil inlet of each control valve group of the at least two control valve groups, the at least two control valve groups correspond to the at least two hydraulic cylinders one by one, and the control valve groups are respectively connected to the rod chamber and the rodless chamber of the corresponding hydraulic cylinder; the detection component is respectively connected to the piston rod of each of the hydraulic cylinders, and the detection component is configured to detect the load force and displacement of the piston rod in each of the hydraulic cylinders; the electronic control component is respectively electrically connected to the detection component and each of the control valve groups, and the electronic control component is configured to: according to the load force and displacement of the piston rod in each of the hydraulic cylinders detected by the detection component, control the opening size of the control valve group corresponding to the hydraulic cylinder so that the displacement of the piston rod of each of the hydraulic cylinders is the same.

[0007] In another implementation of the present disclosure, the electronic control component is configured to: control the opening size of the control valve group corresponding to the hydraulic cylinder according to the load force of the piston rod in each of the hydraulic cylinders detected by the detection component, until the pressure established in the rodless chamber in each of the hydraulic cylinders is equal to the respective theoretical pressures; after the pressure in the rodless chamber in the hydraulic cylinder reaches the theoretical pressure, control the opening size of the control valve group corresponding to the hydraulic cylinder in real time according to the displacement detected by the detection component, so that the displacement of the piston rod of each of the hydraulic cylinders is the same.

[0008] In another implementation of the present disclosure, the electronic control component is used to: when lifting the load, if the displacement detected by the detection component is greater than a target value, then control the opening of the control valve group connected to the hydraulic cylinder detected by the detection component to become smaller; if the displacement detected by the detection component is less than the target value, then control the opening of the control valve group connected to the hydraulic cylinder detected by the detection component to become larger; or, when lowering the load, if the displacement detected by the detection component is less than the target value, then control the opening of the control valve group connected to the hydraulic cylinder detected by the detection component to become smaller; if the displacement detected by the detection component is greater than the target value, then control the opening of the control valve group connected to the hydraulic cylinder detected by the detection component to become larger; wherein the target value is the displacement value of any one of the at least two hydraulic cylinders detected by the detection component.

[0009] In another implementation of the present disclosure, the detection assembly includes at least two pin force sensors and at least two displacement sensors; the at least two pin force sensors are arranged in a one-to-one correspondence with the at least two hydraulic cylinders, and each of the at least two pin force sensors is connected to the piston rod of the corresponding hydraulic cylinder; the at least two displacement sensors are arranged in a one-to-one correspondence with the at least two hydraulic cylinders, and each of the at least two displacement sensors is connected to the piston of the corresponding hydraulic cylinder.

[0010] In another embodiment of the present disclosure, the detection component also includes at least two pressure sensors, and the at least two pressure sensors are arranged in a one-to-one correspondence with the at least two hydraulic cylinders, and each of the at least two pressure sensors is connected to the rodless chamber of the corresponding hydraulic cylinder; the electronic control component is electrically connected to the at least two pressure sensors, and the electronic control component is also configured to: if the difference between the first difference and the second difference is greater than a threshold value, then control each of the control valve groups to be closed; the first difference is the difference between the detection values ​​of the first pressure sensor and the second pressure sensor, and the second difference is the difference between the theoretical pressure of the rodless chamber of the first hydraulic cylinder and the theoretical pressure of the rodless chamber of the second hydraulic cylinder, the first pressure sensor is connected to the first hydraulic cylinder, and the second pressure sensor is connected to the second hydraulic cylinder, and the first pressure sensor and the second pressure sensor are any two of the at least two pressure sensors.

[0011] In another implementation of the present disclosure, the pump group includes a motor, a drive pump body, a variable cylinder and a constant pressure control valve; the motor is connected to the drive pump body, and the oil return port of the drive pump body is respectively connected to the rod chamber of the variable cylinder, the oil inlet of the constant pressure control valve and the control oil port of the constant pressure control valve; the piston rod of the variable cylinder is connected to the variable mechanism of the drive pump body to reduce the displacement of the drive pump body when the piston rod of the variable cylinder extends out of the rod chamber, or to increase the displacement of the drive pump body when the piston rod of the variable cylinder retracts into the rod chamber; the constant pressure control valve is a hydraulically controlled two-position three-way directional valve, the oil return port of the constant pressure control valve is connected to the oil tank, and the control oil port of the constant pressure control valve is connected to its own oil inlet. The working oil port of the constant pressure control valve is connected to the rodless chamber of the variable cylinder.

[0012] In another implementation of the present disclosure, the pump group also includes a load sensing valve, a proportional flow valve and a pilot proportional pressure reducing valve; the oil inlet of the load sensing valve is respectively connected to the oil return port of the drive pump body, the oil inlet of the constant pressure control valve, the first oil port of the proportional flow valve and the oil inlet of the pilot proportional pressure reducing valve, the working oil port of the load sensing valve is connected to the oil return port of the constant pressure control valve, the oil return port of the load sensing valve is connected to the oil tank, and the control oil port of the load sensing valve is connected to its own oil inlet; the spring chamber of the load sensing valve is connected to the second oil port of the proportional flow valve, the control oil port of the proportional flow valve is connected to the working oil port of the pilot proportional pressure reducing valve, and the oil return port of the pilot proportional pressure reducing valve is connected to the oil tank.

[0013] In another implementation of the present disclosure, the pump group also includes a main safety valve, the oil inlet of the main safety valve is respectively connected to its own control oil port and the spring chamber of the load sensing valve, the oil return port of the main safety valve is connected to the oil tank; the spring chamber of the main safety valve is respectively connected to the oil inlet of the load sensing valve.

[0014] In another implementation of the present disclosure, the pump group also includes a pilot proportional overflow valve and a pilot safety valve, the oil inlet of the pilot proportional overflow valve is respectively connected to the oil inlet of the pilot safety valve, the spring chamber of the constant pressure control valve and the spring chamber of the main safety valve, the oil return port of the pilot proportional overflow valve is connected to the oil tank, and the control oil port of the pilot proportional overflow valve is connected to its own oil inlet; the oil return port of the pilot safety valve is connected to the oil tank, and the control oil port of the pilot safety valve is connected to its own oil inlet.

[0015] In another implementation of the present disclosure, the control valve group includes a proportional directional valve, a balancing valve and a pilot proportional reversing valve; the oil inlet of the proportional directional valve is connected to the oil return port of the pump group, the oil return port of the proportional directional valve is connected to the oil tank, the first working oil port of the proportional directional valve is connected to the first oil port of the balancing valve, the second working oil port of the proportional directional valve is respectively connected to the oil inlet of the pilot proportional reversing valve and the rod chamber of the hydraulic cylinder corresponding to the control valve group; the second oil port of the balancing valve is connected to the rodless chamber of the hydraulic cylinder corresponding to the control valve group, and the control oil port of the balancing valve is connected to the working oil port of the pilot proportional reversing valve.

[0016] The technical solution provided by the embodiments of the present disclosure brings the following beneficial effects:

[0017] When the control system provided by the embodiment of the present disclosure performs synchronous control on the hydraulic cylinders, since the detection component in the control system is configured to detect the load force of the piston rod in each hydraulic cylinder, and at the same time, the electronic control component is configured to: according to the different load forces of the piston rods in each hydraulic cylinder detected by the detection component, control the opening size of each control valve group to control the displacement of the piston rods of each hydraulic cylinder to be the same, so that in the actual process of lifting the load, since the rodless chamber pressure of the hydraulic cylinder is determined by the load, the greater the load, the greater the rodless chamber pressure, and the smaller the load, the smaller the rodless chamber pressure. Therefore, under the premise that the load force of the piston rod in each hydraulic cylinder has been determined, the theoretical pressure of the rodless chamber in each hydraulic cylinder can be calculated, and then the pressure difference of the inlet and outlet oil pressure of each control valve group can be obtained, and then the opening size of the two control valve groups can be adjusted in turn according to the pressure difference, so that after the oil can quickly enter the rodless chamber of different hydraulic cylinders, the pressure can be quickly established in the rodless chamber. At the same time, since the detection component can also control the opening size of the control valve group corresponding to the hydraulic cylinder according to the detected displacement of the piston rod in each hydraulic cylinder, so that the displacement of the piston rod of each hydraulic cylinder is the same, the piston rods of the two hydraulic cylinders can have the same extension and retraction speed and the same displacement after being extended, thereby smoothly lifting the offset load. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present disclosure, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present disclosure. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 is a schematic diagram of a control system of a hydraulic cylinder provided in an embodiment of the present disclosure;

[0020] Figure 2 It is a schematic diagram of another control system of a hydraulic cylinder provided in an embodiment of the present disclosure.

[0021] The symbols in the figure mean the following:

[0022] 1. Pump group; 11. Electric motor; 12. Driving pump body; 13. Variable cylinder; 14. Constant pressure control valve; 15. Load sensitive valve; 16. Proportional flow valve; 17. Pilot proportional pressure reducing valve; 18. Main safety valve; 19. Pilot proportional relief valve; 110. Pilot safety valve; 111. Pump body electronic control unit;

[0023] 2. Control valve group; 21. Proportional directional valve; 22. Balance valve; 23. Pilot proportional reversing valve; 24. Shuttle valve; 25. Pressure differential compensator; 26. Safety control valve; 27. Filter;

[0024] 3. Detection component; 31. Pin force sensor; 32. Displacement sensor; 33. Pressure sensor;

[0025] 4. Electronic control components;

[0026] 100, hydraulic cylinder; 200, lifting beam; 300, load. DETAILED DESCRIPTION

[0027] In order to make the objectives, technical solutions and advantages of the present disclosure more clear, the embodiments of the present disclosure will be further described in detail below with reference to the accompanying drawings.

[0028] The present disclosure provides a control system for a hydraulic cylinder. Figure 1 As shown, the control system can control two hydraulic cylinders 100 to drive the lifting beam 200 to rise and fall. Two hydraulic cylinders 100 are arranged at the bottom of the lifting beam 200. A load 300 is arranged at the top of the lifting beam 200.

[0029] The two hydraulic cylinders 100 are symmetrically arranged at both ends of the lifting beam 200. The piston rod of each of the two hydraulic cylinders 100 is hinged to the lifting beam 200 through a pin. In order to ensure that the lifting beam does not tilt during movement and pull the piston rod, the control system is used to drive the piston rods of the two hydraulic cylinders 100 to extend synchronously. In actual operation, the center of gravity of the load 300 is not necessarily located on the symmetry plane of the two hydraulic cylinders 100 (the distance from the load 300 to the two hydraulic cylinders is Figure 1 a and b are different, and the load lifted by the lifting beam is an offset load), so the piston rods of the two hydraulic cylinders 100 are used to support different load forces of the lifting beam, and the pressures of the rodless chambers in the two hydraulic cylinders 100 are different.

[0030] When the pressures in the rodless chambers of the two hydraulic cylinders 100 are different, if the two hydraulic cylinders 100 are controlled according to the control system in the related art, since the rodless chambers of the two hydraulic cylinders 100 are connected through pipelines in the related art, the oil pressures of the rodless chambers of the two hydraulic cylinders are the same. However, since the piston rods of the two hydraulic cylinders 100 are used to support different load forces of the lifting beam, the piston rod of the hydraulic cylinder bearing a larger load force will slow down the extension speed of the piston rod due to the larger load force, so as to further increase the oil pressure of the rodless chamber to balance the load, while the piston rod of the hydraulic cylinder bearing a smaller load force will speed up the extension speed of the piston rod due to the smaller load force, so as to further reduce the oil pressure of the rodless chamber to balance the load. In this way, the extension and retraction speeds of the piston rods of the two hydraulic cylinders 100 are different, and the displacements are also different, that is, the control system in the related art cannot synchronously control the hydraulic cylinders 100.

[0031] It should be noted that the number of hydraulic cylinders 100 mentioned above is for example only but not limiting, and can be set as needed, for example, to control three or four hydraulic cylinders 100 to move synchronously.

[0032] To this end, the embodiment of the present disclosure provides a control system capable of controlling the synchronous movement of at least two hydraulic cylinders. Here, synchronous movement means that the displacements of the piston rods of the at least two hydraulic cylinders always remain the same.

[0033] In this embodiment, the displacements of the piston rods of the hydraulic cylinders 100 are the same, which means that the displacements of the piston rods of the hydraulic cylinders 100 are equal or the difference between them is within a certain range (for example, within 0.1 mm).

[0034] Continue to see Figure 1 The control system includes a pump group 1, at least two control valve groups 2, a detection component 3 and an electronic control component 4. The pump group 1 is connected to the oil inlet of each of the at least two control valve groups 2, the at least two control valve groups 2 correspond to at least two hydraulic cylinders 100 one by one, and the control valve groups 2 are respectively connected to the rod chamber and the rodless chamber of the corresponding hydraulic cylinder 100.

[0035] The detection assembly 3 is respectively connected to the piston rod of each hydraulic cylinder 100, and the detection assembly 3 is configured to detect the load force of the piston rod in each hydraulic cylinder 100. The electric control assembly 4 is respectively electrically connected to the detection assembly 3 and each control valve group 2, and the electric control assembly 4 is configured to: according to the load force and displacement of the piston rod in each hydraulic cylinder 100 detected by the detection assembly 3, control the opening size of the control valve group 2 corresponding to the hydraulic cylinder 100, so that the displacement of the piston rod of each hydraulic cylinder 100 is the same.

[0036] When the control system provided by the embodiment of the present disclosure performs synchronous control on the hydraulic cylinder, since the detection component 3 in the control system is configured to detect the load force of the piston rod in each hydraulic cylinder 100, at the same time, the electronic control component 4 is configured to: according to the different load forces of the piston rods in each hydraulic cylinder 100 detected by the detection component 3, control the opening size of each control valve group 2 to control the displacement of the piston rods of each hydraulic cylinder 100 to be the same, so that in the actual lifting process of the load, the rodless chamber pressure of the hydraulic cylinder is determined by the load. The greater the load, the greater the rodless chamber pressure, and the smaller the load, the smaller the rodless chamber pressure. Therefore, under the premise that the load force of the piston rod in each hydraulic cylinder 100 has been determined, the theoretical pressure of the rodless chamber in each hydraulic cylinder 100 can be calculated, and then the pressure difference of the inlet and outlet oil pressure of each control valve group 2 can be obtained, and then the opening size of each control valve group 2 can be adjusted in turn according to the pressure difference, so that the oil can quickly enter the rodless chamber of different hydraulic cylinders, and the pressure in the rodless chamber can be quickly established. At the same time, since the detection component 3 can also control the opening size of the control valve group 2 corresponding to the hydraulic cylinder 100 according to the detected displacement of the piston rod in each hydraulic cylinder 100, so that the displacement of the piston rod of each hydraulic cylinder 100 is the same, the piston rods of the two hydraulic cylinders can have the same extension and retraction speed and the same displacement after being extended, thereby smoothly lifting the offset load.

[0037] Optionally, the electronic control component 4 is configured to: control the opening size of the control valve group 2 corresponding to the hydraulic cylinder 100 according to the load force of the piston rod in each hydraulic cylinder 100 detected by the detection component 3, until the pressure established in the rodless cavity of each hydraulic cylinder 100 is equal to the respective theoretical pressure.

[0038] According to the displacement detected by the detection component 3, the opening size of the control valve group 2 corresponding to the hydraulic cylinder 100 is controlled in real time so that the displacement of the piston rod of each hydraulic cylinder 100 is the same.

[0039] In the above implementation, the electronic control component 4 is set to the above control mode, so that when the load is lifted, the theoretical pressure of the rodless chamber of each hydraulic cylinder 100 can be obtained according to the load force of the piston rod of each hydraulic cylinder 100, and then the opening size of the corresponding control valve group 2 is adjusted according to the theoretical pressure, so that the pressure of the rodless chamber of each hydraulic cylinder 100 can be quickly established to improve the response and control accuracy of the control system. Because it takes a long time to build pressure simply through the load. After the pressure of the rodless chamber in the hydraulic cylinder 100 is the theoretical pressure, the displacement of each hydraulic cylinder 100 is detected in real time to achieve closed-loop control of the control system, so that the displacement of the hydraulic cylinder 100 is the same, ensuring smooth lifting and lowering of the load.

[0040] In this embodiment, the electronic control component 4 is used to: when lowering the load, if the displacement detected by the detection component 3 is greater than the target value, the opening of the control valve group 2 connected to the hydraulic cylinder 100 detected by the detection component 3 is controlled to become larger. If the displacement detected by the detection component 3 is less than the target value, the opening of the control valve group 2 connected to the hydraulic cylinder 100 detected by the detection component 3 is controlled to become smaller.

[0041] Alternatively, when lifting a load, if the displacement detected by the detection component 3 is greater than the target value, the opening of the control valve group 2 connected to the hydraulic cylinder 100 detected by the detection component 3 is controlled to be smaller. If the displacement detected by the detection component 3 is less than the target value, the opening of the control valve group 2 connected to the hydraulic cylinder 100 detected by the detection component 3 is controlled to be larger. The target value is the displacement value of any one of the at least two hydraulic cylinders detected by the detection component 3.

[0042] When lifting a load, if the displacement of one of the hydraulic cylinders 100 is greater than the displacement of the remaining hydraulic cylinders, it means that the extension speed of the piston rod of the hydraulic cylinder 100 is large. At this time, it is necessary to reduce the extension speed of the piston rod of the hydraulic cylinder 100, which means that the flow rate of the oil entering the rodless chamber of the hydraulic cylinder 100 needs to be reduced. Therefore, it is necessary to reduce the opening size of the control valve group 2. On the contrary, if the displacement of one of the hydraulic cylinders 100 is less than the displacement of the remaining hydraulic cylinders, it means that the extension speed of the piston rod of the hydraulic cylinder 100 is small. At this time, it is necessary to increase the extension speed of the piston rod of the hydraulic cylinder 100, which means that the flow rate of the oil entering the rodless chamber of the hydraulic cylinder 100 needs to be increased. Therefore, it is necessary to increase the opening size of the control valve group 2.

[0043] When lowering the load, if the displacement of one of the hydraulic cylinders 100 is greater than the displacement of the other remaining hydraulic cylinders, it means that the piston rod of the hydraulic cylinder 100 retracts slowly. At this time, it is necessary to increase the retraction speed of the piston rod of the hydraulic cylinder 100, which means that it is necessary to increase the oil flow rate entering the rod chamber of the hydraulic cylinder 100 and increase the oil flow rate flowing out of the rodless chamber of the hydraulic cylinder 100. Therefore, it is necessary to increase the opening size of the control valve group 2. On the contrary, if the displacement of one of the hydraulic cylinders 100 is less than the displacement of the other remaining hydraulic cylinders, it means that the piston rod of the hydraulic cylinder 100 retracts quickly. At this time, it is necessary to reduce the retraction speed of the piston rod of the hydraulic cylinder 100, which means that it is necessary to reduce the oil flow rate entering the rod chamber of the hydraulic cylinder 100 and reduce the oil flow rate flowing out of the rodless chamber of the hydraulic cylinder 100. Therefore, it is necessary to reduce the opening size of the control valve group 2.

[0044] For safety reasons, the target value mentioned above is the minimum displacement value among the displacements corresponding to at least two displacement sensors 32 .

[0045] Figure 2 is a schematic diagram of another hydraulic cylinder control system provided by the embodiment of the present disclosure, combined with Figure 2 Optionally, the detection component 3 includes at least two pin force sensors 31, and the at least two pin force sensors 31 are arranged in a one-to-one correspondence with the at least two hydraulic cylinders 100, and each of the at least two pin force sensors 31 is connected to the piston rod of the corresponding hydraulic cylinder 100.

[0046] The detection assembly 3 further includes at least two displacement sensors 32 , which are arranged in one-to-one correspondence with the at least two hydraulic cylinders 100 , and each of the at least two displacement sensors 32 is connected to the piston of the corresponding hydraulic cylinder 100 .

[0047] In the above implementation, the pin force sensor 31 is used to detect the load force of the piston rod of the hydraulic cylinder 100 corresponding to the pin force sensor 31. When lifting the load, the load force of the piston rods of the two hydraulic cylinders 100 is detected by the pin force sensor 31, and then the detected load force is transmitted to the electronic control component 4, and the electronic control component 4 can calculate the theoretical pressure of the rodless chamber of each hydraulic cylinder 100 according to the load force. For example, the pin force sensor 31 detects the load force of the piston rods of the two hydraulic cylinders 100 in real time, that is, the lifting force F when lifting the load. According to the working principle of the hydraulic cylinder, when lifting or lowering the load, the piston rod needs to provide a lifting force F, then the theoretical pressure of the rodless chamber of the hydraulic cylinder P = F / S, S is the area of ​​the piston.

[0048] Since the outlet of the control valve group 2 is connected to the rodless chamber of the hydraulic cylinder 100, the electric control component 4 obtains the theoretical pressure of the rodless chamber of each hydraulic cylinder 100 according to the load force, and naturally obtains the oil pressure at the outlet of each control valve group 2. Combined with the working parameters of the pump group 1, the oil pressure entering the inlet of each control valve group 2 can be obtained. In this way, the pressure difference of the inlet and outlet oil pressure of each control valve group 2 can be obtained. Since the flow of the control valve group 2 has a certain mathematical relationship with the pressure difference of the inlet and outlet oil pressure and its own opening size, for example, when the control valve group 2 is a proportional valve group, the flow of the control valve group 2 = the product of the 1 / 2 power of the pressure difference of the inlet and outlet oil pressure and its own opening size. Therefore, in order to quickly make the pressure of the rodless chamber of each hydraulic cylinder the theoretical pressure, the opening size of each control valve group 2 can be obtained on the premise of knowing the pressure difference of the inlet and outlet oil pressure of the two control valve groups 2. Then, according to the opening size of the control valve group 2, the opening of the two control valve groups 2 is adjusted so that the pressure in the rodless chamber of each hydraulic cylinder 100 quickly reaches the theoretical pressure.

[0049] The displacement sensor 32 is used to detect the displacement (i.e., stroke) of the piston rods of the two hydraulic cylinders 100 in real time. When the piston rods of the hydraulic cylinders 100 extend to lift the offset load, the displacement of the piston rods of the hydraulic cylinders 100 can be detected in real time through the displacement sensor 32. The displacement sensor 32 transmits the detected displacement to the electronic control component 4. The electronic control component 4 controls the opening size of each control valve group 2 according to the displacement closed loop, so that the flow rate entering the two hydraulic cylinders is the same, realizing the displacement closed loop control of a single hydraulic cylinder and the synchronous displacement control of multiple hydraulic cylinders.

[0050] The opening size of the control valve group 2 mentioned above includes the size of the corresponding communication opening when the control valve group 2 is connected to the rodless chamber of the hydraulic cylinder 100 and the size of the corresponding communication opening when the control valve group 2 is connected to the rod chamber of the hydraulic cylinder 100 .

[0051] In this embodiment, when lifting a load, the control valve group 2 inputs oil into the rodless chamber of the hydraulic cylinder 100. At this time, the opening size of the control valve group 2 is the size of the corresponding communication opening when the control valve group 2 is connected to the rodless chamber of the hydraulic cylinder 100. By adjusting the opening size of the control valve group 2, the flow rate of the oil entering the rodless chamber of the hydraulic cylinder 100 can be adjusted, thereby adjusting the extension speed of the piston rod of the hydraulic cylinder 100.

[0052] When lowering the load, the control valve group 2 inputs oil into the rod chamber of the hydraulic cylinder 100, and at the same time, discharges the oil from the rodless chamber of the hydraulic cylinder. At this time, the opening size of the control valve group 2 includes the size of the corresponding communication opening when the control valve group 2 is connected to the rod chamber of the hydraulic cylinder 100, and also includes the size of the corresponding communication opening when the control valve group 2 is connected to the rodless chamber of the hydraulic cylinder 100. By adjusting the opening size of the control valve group 2, the relative flow of oil in and out of the hydraulic cylinder 100 can be controlled, and then the retraction speed of the piston rod of the hydraulic cylinder 100 can be adjusted. That is, when lowering the load, if the opening size of the control valve group 2 is increased, the size of the corresponding connecting opening when the control valve group 2 is connected to the rod chamber of the hydraulic cylinder 100 is increased, and the size of the corresponding connecting opening when the control valve group 2 is connected to the rodless chamber of the hydraulic cylinder 100 is increased, the flow rate of the oil entering the rod chamber of the hydraulic cylinder 100 increases, and the flow rate of the oil flowing out of the rodless chamber of the hydraulic cylinder 100 also increases, and the retraction speed of the piston rod of the hydraulic cylinder 100 is accelerated.

[0053] In addition, for safety reasons, the detection component 3 also includes at least two pressure sensors 33, which are arranged in a one-to-one correspondence with at least two hydraulic cylinders 100, and each of the at least two pressure sensors 33 is connected to the rodless chamber of the corresponding hydraulic cylinder 100.

[0054] The electronic control component 4 is electrically connected to at least two pressure sensors 33 , and is further configured to control each control valve group 2 to close if the difference between the first difference and the second difference is greater than a threshold value.

[0055] The first difference is the difference between the detection values ​​of the first pressure sensor and the second pressure sensor, and the second difference is the difference between the theoretical pressure of the rodless chamber of the first hydraulic cylinder and the theoretical pressure of the rodless chamber of the second hydraulic cylinder. The first pressure sensor is connected to the first hydraulic cylinder, and the second pressure sensor is connected to the second hydraulic cylinder. The first pressure sensor and the second pressure sensor are any two of the at least two pressure sensors 33.

[0056] The pressure sensor 33 is used to detect the actual pressure of the rodless chamber of the hydraulic cylinder 100 in real time. When the actual working pressure difference of the rodless chambers of any two hydraulic cylinders 100 exceeds a certain range of the theoretical pressure difference, such as 2MPa, the electronic control component 4 controls the control valve group 2 to close, and the hydraulic cylinder stops moving to achieve safety protection.

[0057] Combination Figure 2 , taking the lifting load as an example, the inlet pressure of the control valve group 2 is the same, for example, 20MPa. Assume that the load of the right hydraulic cylinder is large and the load of the left hydraulic cylinder is small. For example, the theoretical pressure of the rodless chamber of the right hydraulic cylinder is 16MPa, and the theoretical pressure of the rodless chamber of the left hydraulic cylinder is 11MPa. The theoretical pressure difference between the two is 5MPa. If the pressure sensor 33 detects that the actual working pressure difference is 7MPa, and the actual working pressure difference exceeds the theoretical pressure difference of 2MPa, it means that the load of one hydraulic cylinder is too large and the load of the other hydraulic cylinder is too small. The two hydraulic cylinders may be out of sync, so the hydraulic cylinders need to stop moving to achieve safety protection.

[0058] Continue to see Figure 2 Optionally, the pump group 1 includes a motor 11, a driving pump body 12, a variable cylinder 13 and a constant pressure control valve 14. The motor 11 is connected to the driving pump body 12, and the oil return port of the driving pump body 12 is respectively connected to the rod chamber of the variable cylinder 13 and the oil inlet of the constant pressure control valve 14.

[0059] The piston rod of the variable cylinder 13 is connected to the variable mechanism of the drive pump body 12, so as to reduce the displacement of the drive pump body 12 when the piston rod of the variable cylinder 13 is extended, and increase the displacement of the drive pump body 12 when the piston rod of the variable cylinder 13 is retracted. The constant pressure control valve 14 is a hydraulically controlled two-position three-way directional valve, the return oil port of the constant pressure control valve 14 is connected to the oil tank, and the control oil port of the constant pressure control valve 14 is connected to its own oil inlet. The working oil port of the constant pressure control valve 14 is connected to the rodless chamber of the variable cylinder 13.

[0060] In the above implementation, the motor 11 is used to drive the driving pump body 12 to work, and the driving pump body 12 is used to pressurize the oil in the oil tank and pump it into the control valve group 2.

[0061] The variable cylinder 13 is used to be connected to the variable mechanism of the driving pump body 12 to adjust the displacement of the driving pump body 12, thereby controlling the flow of oil entering the hydraulic cylinder 100 from the source, avoiding overspeed, etc., and improving the safety of the control system.

[0062] The constant pressure control valve 14 is used to be connected to the variable cylinder 13 so as to control the flow rate and pressure of the oil in the rodless chamber of the variable cylinder 13 , thereby controlling the extension and retraction state of the piston rod of the variable cylinder 13 .

[0063] For example, when the oil pressure difference between the control oil port x of the constant pressure control valve 14 and the spring chamber y is greater than the spring force, the constant pressure control valve 14 works in the right position, the oil return port T of the constant pressure control valve 14 is blocked, and the oil in the constant pressure control valve 14 flows from the oil inlet P to the working oil port A, that is, P→A, driving the oil pumped out of the pump body 12 into the rodless chamber of the variable cylinder 13 through the constant pressure control valve 14, and the piston rod of the variable cylinder 13 extends, driving the displacement of the pump body 12 to decrease. When the oil pressure difference between the control oil port x of the constant pressure control valve 14 and the spring chamber y is not greater than the spring force, the constant pressure control valve 14 works in the left position, the oil inlet P of the constant pressure control valve 14 is blocked, and the oil in the constant pressure control valve 14 flows from the working oil port A to the return oil port T, that is, A→T, driving the oil pumped out of the pump body 12 to enter the rod chamber of the variable cylinder 13 through the constant pressure control valve 14, and the piston rod of the variable cylinder 13 retracts, driving the displacement of the pump body 12 to increase.

[0064] Optionally, the pump group 1 further includes a load sensing valve 15, a proportional flow valve 16 and a pilot proportional pressure reducing valve 17. The oil inlet of the load sensing valve 15 is respectively connected to the oil return port of the driving pump body 12, the oil inlet of the constant pressure control valve 14, the first oil port of the proportional flow valve 16 and the oil inlet of the pilot proportional pressure reducing valve 17, the working oil port A of the load sensing valve 15 is connected to the oil return port of the constant pressure control valve 14, the oil return port of the load sensing valve 15 is connected to the oil tank, and the control oil port of the load sensing valve 15 is connected to its own oil inlet. The spring chamber of the load sensing valve 15 is connected to the second oil port of the proportional flow valve 16, the control oil port of the proportional flow valve 16 is connected to the working oil port of the pilot proportional pressure reducing valve 17, and the oil return port of the pilot proportional pressure reducing valve 17 is connected to the oil tank.

[0065] In the above implementation, when the pressure difference of the control oil port x of the load sensing valve 15 minus the pressure of the spring chamber y port is less than the spring force, the load sensing valve 15 works in the left position, that is, the oil inlet P of the load sensing valve 15 is blocked, and the oil flows from A→T, and the oil in the rodless chamber of the variable cylinder 13 flows out through the constant pressure control valve 14 and the load sensing valve 15, and the piston rod of the variable cylinder 13 retracts, driving the variable displacement of the pump body 12 to increase. Conversely, when the pressure of the control oil port x of the load sensing valve 15 minus the pressure of the spring chamber y port is greater than the spring force, the load sensing valve 15 works in the right position, that is, the return oil port T of the load sensing valve 15 is blocked, and the oil flows from P→A, driving the oil in the return oil port P of the pump body 12 into the rodless chamber of the variable cylinder 13 through the load sensing valve 15, and the piston rod of the variable cylinder 13 extends, driving the displacement of the pump body 12 to decrease.

[0066] Since the position of the valve core of the load sensing valve 15 is directly limited by the relationship between the control oil port x and the oil pressure of the spring chamber y port. The oil inlet P of the load sensing valve 15 is connected to the first oil port A of the proportional flow valve 16, and the spring chamber y port of the load sensing valve 15 is connected to the second oil port B of the proportional flow valve 16, so the load sensing valve 15 can stabilize the pressure difference between the first oil port A and the second oil port B of the proportional flow valve 16. When the pressure difference is less than the spring force of the load sensing valve 15, the load sensing valve 15 works in the left position, driving the displacement of the pump body 12 to increase until the pressure difference is equal to the spring force of the load sensing valve 15. When the pressure difference between the first oil port A and the second oil port B of the proportional flow valve 16 is greater than the spring force of the load sensing valve 15, the load sensing valve 15 works in the right position, driving the displacement of the pump body 12 to decrease until the pressure difference is equal to the spring force of the load sensing valve 15. The load sensing valve 15 makes the flow of the proportional flow valve 16 only related to its opening size, realizing flow regulation independent of load pressure. The pilot proportional pressure reducing valve 17 is used to remotely adjust the x pressure of the control oil port of the proportional flow valve 16, that is, to steplessly adjust the opening size and flow of the proportional flow valve 16. In addition, in order to limit the oil flow direction between the working oil port A of the load sensing valve 15 and the working oil port A of the constant pressure control valve 14, a right check valve is connected between the working oil port A of the load sensing valve 15 and the working oil port A of the constant pressure control valve 14, the oil inlet of the check valve is connected to the working oil port A of the load sensing valve 15, and the oil return port of the check valve is connected to the working oil port A of the constant pressure control valve 14.

[0067] Optionally, the pump group 1 further includes a main safety valve 18, the oil inlet of the main safety valve 18 is respectively connected to its own control oil port and the spring chamber of the load sensing valve 15, and the oil return port of the main safety valve 18 is connected to the oil tank. The spring chamber of the main safety valve 18 is connected to the oil inlet of the load sensing valve 15.

[0068] In the above implementation, when the pressure of the second oil port B of the proportional flow valve 16 is greater than the set pressure of the main safety valve 18, the oil inlet P of the main safety valve 18 is connected to the oil return port T, and the oil flows from P→T. The oil in the spring chamber y port of the load sensing valve 15 flows back to the oil tank through the main safety valve 18, and the load sensing valve 15 works in the right position, driving the displacement of the pump body 12 to decrease, thereby achieving safety protection.

[0069] Optionally, the pump group 1 further includes a pilot proportional relief valve 19 and a pilot safety valve 110. The oil inlet of the pilot proportional relief valve 19 is respectively connected to the oil inlet of the pilot safety valve 110, the spring chamber of the constant pressure control valve 14 and the spring chamber of the main safety valve 18, the oil return port of the pilot proportional relief valve 19 is connected to the oil tank, and the control oil port of the pilot proportional relief valve 19 is connected to its own oil inlet. The oil return port of the pilot safety valve 110 is connected to the oil tank, and the control oil port of the pilot safety valve 110 is connected to its own oil inlet.

[0070] In the above implementation, the pilot proportional relief valve 19 is used to remotely adjust the constant pressure setting value of the driving pump body 12 and the pressure setting value of the main safety valve 18. The pilot safety valve 110 is used to mechanically limit the maximum pressure setting value, that is, pressure limiting safety protection.

[0071] In addition, in order to facilitate the control of the opening size of the proportional flow valve 16, a flow meter is connected to the second working oil port of the proportional flow valve 16. The pump group 1 also includes a pump body electronic control unit 111, which is electrically connected to the flow meter and the pilot proportional pressure reducing valve 17 respectively.

[0072] Optionally, the control valve group 2 includes a proportional directional valve 21, a balancing valve 22 and a pilot proportional reversing valve 23. The oil inlet of the proportional directional valve 21 is connected to the oil return port of the pump group 1, the oil return port of the proportional directional valve 21 is connected to the oil tank, the first working oil port of the proportional directional valve 21 is connected to the oil inlet of the balancing valve 22, and the second working oil port of the proportional directional valve 21 is respectively connected to the oil inlet of the pilot proportional reversing valve 23 and the rod chamber of the hydraulic cylinder corresponding to the control valve group 2. The oil return port of the balancing valve 22 is connected to the rodless chamber of the hydraulic cylinder corresponding to the control valve group 2, and the control oil port of the balancing valve 22 is connected to the working oil port of the pilot proportional reversing valve 23.

[0073] When the proportional directional valve 21 works in the right position, that is, when lifting the load, the oil in the proportional directional valve 21 flows from P→A, B→T, and the pressure oil at the first working oil port A of the proportional directional valve 21 enters the rodless chamber of the hydraulic cylinder 100 through the one-way function of the left position of the balance valve 22, and the oil in the rod chamber of the hydraulic cylinder 100 flows back to the oil tank through the second working oil port B→return oil port T of the proportional directional valve 21. At the same time, the pilot proportional reversing valve 23 loses power and works in the lower position under the action of the spring force. The oil inlet P of the pilot proportional reversing valve 23 is blocked, and the working oil port A of the pilot proportional reversing valve 23 is connected to the return oil port T, and the oil flows from A→T. The pilot proportional reversing valve 23 cannot control the throttling position of the balance valve 22 in the right position, and the balance valve 22 always works in the left position. At this time, the opening of the control valve group 2 is the opening size of the proportional directional valve 21. The larger the opening of the proportional directional valve 21, the greater the flow rate of the oil entering the rodless chamber of the hydraulic cylinder 100, the greater the extension speed of the piston rod of the hydraulic cylinder 100, and the greater the displacement per unit time of the hydraulic cylinder 100. Therefore, the extension speed of the piston rod of the hydraulic cylinder 100 can be controlled by controlling the opening of the proportional directional valve 21 through the electronic control component 4.

[0074] When the proportional directional valve 21 works in the left position, the oil in the proportional directional valve 21 flows from P→B, A→T, and the oil flows from the second working oil port B of the proportional directional valve 21 into the rod chamber of the hydraulic cylinder 100. At the same time, the pilot proportional reversing valve 23 is energized, and the upper position of the pilot proportional reversing valve 23 works. The oil inlet P of the pilot proportional reversing valve 23 is connected with the working oil port A, and the return oil port T is blocked, and the oil flows from P→A, T. The pressure oil at the second working oil port B of the proportional directional valve 21 enters the control oil port x of the balance valve 22 through the pilot proportional reversing valve 23, pushing the balance valve 22 to work in the throttling position of the right position, and the oil in the rodless chamber of the hydraulic cylinder flows back to the oil tank through the balance valve and the first working oil port A→T of the proportional directional valve 21. At this time, the opening of the control valve group 2 includes the opening of the proportional directional valve 21 and the throttling opening size of the balance valve 22. The larger the opening of the proportional directional valve 21, the greater the flow rate of the oil entering the rod chamber of the hydraulic cylinder 100. The larger the throttling opening of the balance valve 22, the greater the flow rate of the oil flowing out of the rodless chamber of the hydraulic cylinder 100. Therefore, the greater the retraction speed of the piston rod of the hydraulic cylinder 100, the greater the displacement of the hydraulic cylinder 100 per unit time. The throttling opening of the balance valve 22 is limited by the opening size of the pilot proportional reversing valve 23. The larger the opening of the pilot proportional reversing valve 23, the larger the throttling opening of the balance valve 22. Therefore, the retraction speed of the piston rod of the hydraulic cylinder 100 can be controlled by controlling the opening of the proportional directional valve 21 and the opening of the pilot proportional reversing valve 23 through the electronic control component 4.

[0075] Optionally, the control valve group 2 also includes a shuttle valve 24 and a pressure difference compensator 25, the shuttle valve 24 is connected between the proportional directional valve 21 and the balancing valve 22, the first oil port of the shuttle valve 24 is connected to the first working oil port of the proportional directional valve 21, and the second oil port of the shuttle valve 24 is connected to the second working oil port of the proportional directional valve 21.

[0076] The pressure differential compensator 25 is connected between the pump group 1 and the proportional directional valve 21, the oil inlet of the pressure differential compensator 25 is connected to the oil return port of the pump group 1, the oil return port of the pressure differential compensator 25 is connected to the oil inlet of the proportional directional valve 21, and the control oil port of the pressure differential compensator 25 is connected to the oil return port of the shuttle valve 24.

[0077] The shuttle valve 24 can transfer the high-pressure oil pressure in the first working oil port A and the second working oil port B of the proportional directional valve 21 to the spring chamber of the differential pressure compensator 25, so that the differential pressure between the oil inlet P of the proportional directional valve 21 and the first working oil port A and the second working oil port B is equal to the setting value of the differential pressure compensator 25, ensuring that the flow rate passing through the proportional directional valve 21 is only related to the size of its valve core opening and has nothing to do with the load, thereby improving the control accuracy of the proportional directional valve 21.

[0078] That is to say, the differential pressure compensator 25 is used to stabilize the differential pressure between the oil inlet side and the oil outlet side of the proportional directional valve 21. The first oil port A and the second oil port B of the shuttle valve 24 are respectively connected to the first working oil port A and the second working oil port B of the proportional directional valve 21, and the pressure of the return oil port C of the shuttle valve 24 is always the higher pressure of the first working oil port A and the second working oil port B of the proportional directional valve 21. When the proportional directional valve 21 works in the right position, P→A, B→T, the pressure at the first working oil port A of the proportional directional valve 21 is transmitted to the control oil port x of the differential pressure compensator 25 through the return oil port C of the shuttle valve 24. The differential pressure P→A of the proportional directional valve 21 is always the spring setting pressure of the differential pressure compensator 25, and the flow rate of the proportional directional valve 21 is only related to its opening size. When the proportional directional valve 21 works in the left position, similar to the above, the oil in the proportional directional valve 21 changes from P→B, A→T, and the pressure of the second working oil port B of the proportional directional valve 21 is transmitted to the control oil port x of the pressure differential compensator 25 through the return oil port C of the shuttle valve 24. The P→B ​​pressure difference of the proportional directional valve 21 is always the spring setting pressure of the pressure differential compensator 25, and the flow of the proportional directional valve 21 is only related to the size of its opening.

[0079] Optionally, the control valve group 2 also includes a safety control valve 26, the oil inlet of the safety control valve 26 is respectively connected to the first working oil port of the proportional directional valve 21 and the first oil port of the shuttle valve 24, the oil return port of the safety control valve 26 is respectively connected to the first oil port A of the balance valve 22 and the rodless chamber of the hydraulic cylinder corresponding to the control valve group 2, and the control oil port of the safety control valve 26 is connected to its own oil return port.

[0080] In the above implementation, the safety control valve 26 is used to control the oil pressure entering the second oil port B of the balance valve 22 , thereby controlling the oil pressure of the oil entering the rodless chamber of the hydraulic cylinder 100 .

[0081] When the pressure at the second oil port B of the balancing valve 22 is greater than the set pressure of the safety control valve 26, the oil inlet of the safety control valve 26 is connected to the oil return port, and the oil at the first oil port A of the balancing valve 22 is depressurized and flows back to the oil tank.

[0082] Optionally, the control valve group 2 also includes a filter 27, which is connected to the oil circuit between the shuttle valve 24 and the pilot proportional reversing valve 23, the oil inlet of the filter 27 is connected to the second oil port B of the shuttle valve 24, and the oil return port of the filter 27 is connected to the oil inlet P of the pilot proportional reversing valve 23.

[0083] The filter 27 is used to filter the oil entering the pilot proportional reversing valve 23 to prevent impurities from entering the pilot proportional reversing valve 23 .

[0084] Optionally, the electric control component 4 is a controller, which can be a computer or a single chip microcomputer equipped with a control program.

[0085] The following briefly introduces the working process of the control system provided by the embodiment of the present disclosure:

[0086] Before operation, adjust the control signal of the pilot proportional relief valve 19 in pump group 1 according to the size of the bias load to prevent overloading. According to the lifting or lowering speed requirements, adjust the control signal of the pilot proportional pressure reducing valve 17 in pump group 1 to set the output flow of pump group 1 from the source to prevent overspeed.

[0087] When lifting the load, the right position of the proportional directional valve 21 works, and the oil in the proportional directional valve 21 changes from P→A, B→T. The pressure at the first working oil port A of the proportional directional valve 21 is transmitted to the control oil port x of the pressure differential compensator 25 through the return oil port C of the shuttle valve 24. The P→A pressure difference of the proportional directional valve 21 is always the spring setting pressure of the pressure differential compensator 25, and the flow rate is only related to its opening size. The pressure oil at the first working oil port A of the proportional directional valve 21 enters the rodless chamber of the hydraulic cylinder 100 through the one-way function of the left position of the balance valve 22 to push the piston rod out. The oil in the rod chamber of the hydraulic cylinder 100 returns to the oil tank through B→T of the proportional directional valve 21. At the same time, the pilot proportional reversing valve 23 loses power and works in the lower position under the action of the spring force. The oil inlet P of the pilot proportional reversing valve 23 is blocked, and the oil changes from A→T.

[0088] At the same time, the pin force sensor 31 detects the load force of the piston rods of the two hydraulic cylinders 100 in real time, the electronic control component 4 calculates the theoretical pressure and difference of the rodless chambers of the two hydraulic cylinders 100, and detects the actual working pressure of the rodless chambers of the two hydraulic cylinders 100 in real time through the pressure sensor 33. When the actual working pressure difference of the rodless chambers of the two hydraulic cylinders exceeds a certain range of the theoretical pressure difference, such as 2MPa, the system stops working to achieve safety protection.

[0089] The displacement sensor 32 detects the displacement of the piston rod in real time and transmits it to the electronic control component 4. The electronic control component 4 controls the proportional directional valve 21 to achieve closed-loop control of the displacement of a single hydraulic cylinder 100 and synchronous control of the displacement of two hydraulic cylinders.

[0090] When the load is lowered, the left position of the proportional directional valve 21 works, and the oil in the proportional directional valve 21 is P→B, A→T. The pressure at the second working oil port B of the proportional directional valve 21 is transmitted to the control oil port x of the differential pressure compensator 25 through the return oil port C of the shuttle valve 24. The P→B ​​differential pressure of the proportional directional valve 21 is always the spring setting pressure of the differential pressure compensator 25, and the flow rate is only related to its opening size. The pressure oil at the second working oil port B of the proportional directional valve 21 enters the rod chamber of the hydraulic cylinder 100, and at the same time, the pilot proportional reversing valve 23 is energized and works in the upper position, and the oil P→A, T in the pilot proportional reversing valve 23 is blocked. The pressure oil at the second working oil port B of the proportional directional valve 21 enters the control oil port x of the balance valve 22 through the filter 27 and the pilot proportional reversing valve 23, and pushes the balance valve 22 to work in the throttling function of the right position. The rodless chamber oil of the hydraulic cylinder 100 returns to the oil tank through the balance valve 22 and the A→T of the proportional directional valve 21.

[0091] At the same time, the pin force sensor 31 detects the load force of the piston rods of the two hydraulic cylinders 100 in real time, the electronic control component 4 calculates the theoretical pressure and difference of the rodless chambers of the two hydraulic cylinders 100, and detects the actual working pressure of the rodless chambers of the two hydraulic cylinders 100 in real time through the pressure sensor 33. When the actual working pressure difference of the rodless chambers of the two hydraulic cylinders exceeds a certain range of the theoretical pressure difference, such as 2MPa, the system stops working to achieve safety protection.

[0092] By adjusting the control signal of the pilot proportional reversing valve 23, the throttle size of the balance valve 22 and the rodless chamber pressure of the hydraulic cylinder 100 can be adjusted to achieve pressure correction. The displacement sensor 32 detects the displacement of the piston rod in real time and transmits it to the electronic control component 4, which controls the proportional directional valve 21 to achieve closed-loop control of the displacement of a single hydraulic cylinder 100 and synchronous control of the displacement of multiple hydraulic cylinders.

[0093] The above description is only an optional embodiment of the present disclosure and is not intended to limit the present disclosure. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present disclosure shall be included in the protection scope of the present disclosure.

Claims

1. A control system for a hydraulic cylinder, characterized in that: Used to control the synchronous movement of at least two hydraulic cylinders, the control system comprises a pump group (1), at least two control valve groups (2), a detection component (3) and an electronic control component (4); The pump group (1) is connected to the oil inlet of each control valve group (2) of the at least two control valve groups (2), the at least two control valve groups (2) correspond to the at least two hydraulic cylinders (100) one by one, and the control valve groups (2) are respectively connected to the rod chamber and the rodless chamber of the corresponding hydraulic cylinder (100); The detection assembly (3) is respectively connected to the piston rod of each hydraulic cylinder (100), and the detection assembly (3) is configured to detect the load force and displacement of the piston rod in each hydraulic cylinder (100); The electronic control component (4) is electrically connected to the detection component (3) and each of the control valve groups (2), respectively, and the electronic control component (4) is configured to: control the opening size of the control valve group (2) corresponding to the hydraulic cylinder (100) according to the load force and displacement of the piston rod in each of the hydraulic cylinders (100) detected by the detection component (3), so that the displacement of the piston rod of each of the hydraulic cylinders (100) is the same.

2. The control system according to claim 1, characterized in that: The electronic control component (4) is configured as follows: According to the load force of the piston rod in each hydraulic cylinder (100) detected by the detection component (3), the opening size of the control valve group (2) corresponding to the hydraulic cylinder (100) is controlled until the pressure established in the rodless cavity of each hydraulic cylinder (100) is equal to the respective theoretical pressure; After the pressure of the rodless chamber in the hydraulic cylinder (100) reaches the theoretical pressure, the opening size of the control valve group (2) corresponding to the hydraulic cylinder (100) is controlled in real time according to the displacement detected by the detection component (3), so that the displacement of the piston rod of each hydraulic cylinder (100) is the same.

3. The control system according to claim 2, characterized in that: The electric control component (4) is used to: when lifting a load, if the displacement detected by the detection component (3) is greater than a target value, control the opening of the control valve group (2) connected to the hydraulic cylinder (100) detected by the detection component (3) to become smaller; if the displacement detected by the detection component (3) is less than the target value, control the opening of the control valve group (2) connected to the hydraulic cylinder (100) detected by the detection component (3) to become larger; Alternatively, when lowering the load, if the displacement detected by the detection component (3) is less than the target value, the opening of the control valve group (2) connected to the hydraulic cylinder (100) detected by the detection component (3) is controlled to become smaller; if the displacement detected by the detection component (3) is greater than the target value, the opening of the control valve group (2) connected to the hydraulic cylinder (100) detected by the detection component (3) is controlled to become larger; The target value is the displacement value of any one of the at least two hydraulic cylinders (100) detected by the detection component (3).

4. The control system according to claim 3, characterized in that: The detection assembly (3) comprises at least two pin force sensors (31) and at least two displacement sensors (32); The at least two pin force sensors (31) are arranged in one-to-one correspondence with the at least two hydraulic cylinders (100), and each of the at least two pin force sensors (31) is connected to the piston rod of the corresponding hydraulic cylinder (100); The at least two displacement sensors (32) are arranged in a one-to-one correspondence with the at least two hydraulic cylinders (100), and each of the at least two displacement sensors (32) is connected to the piston of the corresponding hydraulic cylinder (100).

5. The control system according to claim 4, characterized in that: The detection assembly (3) further comprises at least two pressure sensors (33), wherein the at least two pressure sensors (33) are arranged in a one-to-one correspondence with the at least two hydraulic cylinders (100), and each of the at least two pressure sensors (33) is connected to a rodless chamber of the corresponding hydraulic cylinder (100); The electronic control component (4) is electrically connected to the at least two pressure sensors (33), and the electronic control component (4) is further configured to: if the difference between the first difference and the second difference is greater than a threshold value, control each of the control valve groups (2) to be closed; The first difference is the difference between the detection values ​​of the first pressure sensor and the second pressure sensor, the second difference is the difference between the theoretical pressure of the rodless chamber of the first hydraulic cylinder and the theoretical pressure of the rodless chamber of the second hydraulic cylinder, the first pressure sensor is connected to the first hydraulic cylinder, the second pressure sensor is connected to the second hydraulic cylinder, and the first pressure sensor and the second pressure sensor are any two of the at least two pressure sensors (33).

6. The control system according to any one of claims 1 to 5, characterized in that: The pump group (1) comprises an electric motor (11), a driving pump body (12), a variable cylinder (13) and a constant pressure control valve (14); The motor (11) is connected to the driving pump body (12), and the oil return port of the driving pump body (12) is respectively connected to the rod chamber of the variable cylinder (13), the oil inlet of the constant pressure control valve (14), and the control oil port of the constant pressure control valve (14); The piston rod of the variable cylinder (13) is connected to the variable mechanism of the drive pump body (12) so as to reduce the displacement of the drive pump body (12) when the piston rod of the variable cylinder (13) is extended, or to increase the displacement of the drive pump body (12) when the piston rod of the variable cylinder (13) is retracted; The constant pressure control valve (14) is a hydraulically controlled two-position three-way directional valve, the oil return port of the constant pressure control valve (14) is connected to the oil tank, the control oil port of the constant pressure control valve (14) is connected to its own oil inlet, and the working oil port of the constant pressure control valve (14) is connected to the rodless chamber of the variable cylinder (13).

7. The control system according to claim 6, characterized in that: The pump group (1) further comprises a load sensing valve (15), a proportional flow valve (16) and a pilot proportional pressure reducing valve (17); The oil inlet of the load sensing valve (15) is respectively connected to the oil return port of the driving pump body (12), the oil inlet of the constant pressure control valve (14), the first oil port of the proportional flow valve (16) and the oil inlet of the pilot proportional pressure reducing valve (17); the working oil port of the load sensing valve (15) is connected to the oil return port of the constant pressure control valve (14); the oil return port of the load sensing valve (15) is connected to the oil tank; and the control oil port of the load sensing valve (15) is connected to its own oil inlet; The spring chamber of the load sensing valve (15) is connected to the second oil port of the proportional flow valve (16), the control oil port of the proportional flow valve (16) is connected to the working oil port of the pilot proportional pressure reducing valve (17), and the oil return port of the pilot proportional pressure reducing valve (17) is connected to the oil tank.

8. The control system according to claim 7, characterized in that: The pump assembly (1) further comprises a main safety valve (18), the oil inlet of the main safety valve (18) being connected to its own control oil port and the spring chamber of the load sensing valve (15), respectively, and the oil return port of the main safety valve (18) being connected to the oil tank; The spring chamber of the main safety valve (18) is connected to the oil inlet of the load sensing valve (15).

9. The control system according to claim 8, characterized in that: The pump assembly (1) further comprises a pilot proportional relief valve (19) and a pilot safety valve (110). The oil inlet of the pilot proportional relief valve (19) is respectively connected to the oil inlet of the pilot safety valve (110), the spring chamber of the constant pressure control valve (14) and the spring chamber of the main safety valve (18); the oil return port of the pilot proportional relief valve (19) is connected to the oil tank; and the control oil port of the pilot proportional relief valve (19) is connected to its own oil inlet; The oil return port of the pilot safety valve (110) is connected to the oil tank, and the control oil port of the pilot safety valve (110) is connected to its own oil inlet.

10. The control system according to any one of claims 1-5, 7-9, characterized in that: The control valve group (2) comprises a proportional directional valve (21), a balancing valve (22) and a pilot proportional reversing valve (23); The oil inlet of the proportional directional valve (21) is connected to the oil return port of the pump group (1), the oil return port of the proportional directional valve (21) is connected to the oil tank, the first working oil port of the proportional directional valve (21) is connected to the first oil port of the balance valve (22), and the second working oil port of the proportional directional valve (21) is respectively connected to the oil inlet of the pilot proportional reversing valve (23) and the rod chamber of the hydraulic cylinder corresponding to the control valve group (2); The second oil port of the balancing valve (22) is connected to the rodless chamber of the hydraulic cylinder corresponding to the control valve group (2), and the control oil port of the balancing valve (22) is connected to the working oil port of the pilot proportional reversing valve (23).

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