Control method of hydraulic control system

Abstract

The invention discloses a control method of a hydraulic control system. A lifting unloading platform is provided with a height detection system; the hydraulic control system comprises an oil tank, a processor, a lifting oil cylinder and a lifting oil cylinder control oil way, the lifting oil cylinder control oil way is connected with the lifting oil cylinder and the oil tank, and the processor is electrically connected with the lifting oil cylinder control oil way and the height detection system. Based on the starting signal, the hydraulic control system is controlled to boost through the lifting oil cylinder control oil way, and the lifting oil cylinder is controlled to ascend or descend; a height detection system is used for obtaining the first height of a butt joint cargo platform in butt joint with the lifting unloading platform and the second height of the lifting unloading platform; and based on the comparison result of the first height and the second height, the opening degree of a lifting oil cylinder control oil way is controlled so as to control the ascending speed or the descending speed of the lifting unloading platform. By comparing the two pieces of height information, the opening degree of a lifting oil cylinder control oil way is accurately controlled.

Description

Technical Field

[0001] The present application relates to the technical field of transportation and unloading, and particularly to a control method for a hydraulic control system. Background Art

[0002] Currently, scissor lift unloading platforms are widely used in the fields of logistics and warehousing to achieve the loading, unloading, and height docking of goods. However, the existing scissor lift platforms have the following disadvantages: First, the floating problem of the lift platform during loading and unloading, especially the difficulty in floating control on large-tonnage platforms; Second, the descending speed of the lift platform cannot be automatically adjusted according to the load change, resulting in inconvenient operation and low efficiency; Third, the hydraulic system fluctuates greatly during startup and shutdown, affecting the smoothness and safety of the lift platform operation. These problems limit the application of the existing lift unloading platforms under high-precision, high-efficiency, and high-load conditions. Therefore, an improved control method is needed to solve the above problems. Summary of the Invention

[0003] The purpose of the present application is to provide a control method for a hydraulic control system to solve the above technical problems in the prior art and improve the precision, efficiency, and smoothness of the lift unloading platform.

[0004] The present application provides a control method for a hydraulic control system, which is applied to the hydraulic control system of a lift unloading platform. The lift unloading platform is provided with a height detection system for obtaining the height information of the lift unloading platform; the hydraulic control system includes an oil tank, a processor, a lift cylinder, and a lift cylinder control oil circuit. The lift cylinder control oil circuit connects the lift cylinder and the oil tank, and the processor is electrically connected to the lift cylinder control oil circuit and the height detection system. It is characterized by including:

[0005] Obtaining a start signal by using the processor;

[0006] Based on the start signal, controlling the hydraulic control system to boost pressure through the lift cylinder control oil circuit, and controlling the lift cylinder to perform ascending or descending operations;

[0007] Obtaining the first height of the docking platform docked by the lift unloading platform by using the height detection system, and obtaining the second height of the lift unloading platform by using the height detection system;

[0008] Based on the comparison result of the first height and the second height, controlling the opening degree of the lift cylinder control oil circuit to control the ascending speed or descending speed of the lift unloading platform.

[0009] Further, the lift cylinder control oil circuit includes a two-position four-way electromagnetic directional control valve; the step of controlling the hydraulic control system to boost pressure through the lift cylinder control oil circuit based on the start signal and controlling the lift cylinder to perform ascending or descending operations includes:

[0010] In response to obtaining a start signal, control the two-position four-way electromagnetic directional valve to switch from the power-off state to the power-on state.

[0011] Further, the control oil circuit of the lifting cylinder includes a one-way electromagnetic directional valve and a proportional speed control valve; the step of controlling the opening degree of the control oil circuit of the lifting cylinder based on the comparison result between the first height and the second height to control the rising speed or the falling speed of the lifting and unloading platform includes:

[0012] In response to the hydraulic control system boosting pressure, control the one-way electromagnetic directional valve to be energized;

[0013] Based on the comparison result between the first height and the second height, use a processor to control the proportional speed control valve.

[0014] Further, the step of using a processor to control the proportional speed control valve based on the comparison result between the first height and the second height includes:

[0015] In response to the one-way electromagnetic directional valve being energized, control the opening degree of the proportional speed control valve to decrease to a first preset value to control the rising speed of the lifting and unloading platform to increase to a first preset speed.

[0016] Further, the step of using a processor to control the proportional speed control valve based on the comparison result between the first height and the second height includes:

[0017] In response to the difference between the second height and the first height being less than a first threshold value, control the opening degree of the proportional speed control valve to increase from the first preset value to a second preset value to control the rising speed of the lifting and unloading platform to decrease from the first preset speed to a second preset speed;

[0018] In response to the difference between the second height and the first height being equal to zero, control the two-position four-way electromagnetic directional valve to switch from the power-on state to the power-off state, control the one-way electromagnetic directional valve to be de-energized, and control the opening degree of the proportional speed control valve to increase from the second preset value to the maximum value.

[0019] Further, the control oil circuit of the lifting cylinder includes a two-position four-way electromagnetic directional valve; the step of controlling the hydraulic control system to boost pressure through the control oil circuit of the lifting cylinder based on the start signal and controlling the lifting cylinder to perform a rising or falling operation includes:

[0020] In response to obtaining a start signal, control the two-position four-way electromagnetic directional valve to remain in the power-off state.

[0021] Further, the control oil circuit of the lifting cylinder includes a one-way electromagnetic directional valve and a one-way electro-hydraulic throttle valve; the step of controlling the opening degree of the control oil circuit of the lifting cylinder based on the comparison result between the first height and the second height to control the rising speed or the falling speed of the lifting and unloading platform includes:

[0022] Control the one-way electromagnetic directional valve to be energized;

[0023] Based on the comparison result of the first height and the second height, a processor is used to control the one-way electro-hydraulic throttle valve.

[0024] Furthermore, the step of using a processor to control the one-way electro-hydraulic throttle valve based on the comparison result of the first height and the second height includes:

[0025] In response to the energization of the one-way electromagnetic directional valve, control the opening of the one-way electro-hydraulic throttle valve to increase to a first set value, so as to control the descending speed of the lifting and unloading platform to increase to a third preset speed.

[0026] Furthermore, the step of using a processor to control the one-way electro-hydraulic throttle valve based on the comparison result of the first height and the second height includes:

[0027] In response to the difference between the first height and the second height being greater than a second threshold and less than a third threshold, control the opening of the one-way electro-hydraulic throttle valve to decrease from the first set value to a second set value, so as to control the descending speed of the lifting and unloading platform to decrease from the third preset speed to a fourth preset speed;

[0028] In response to the difference between the second height and the first height being equal to the third threshold, control the one-way electromagnetic directional valve to de-energize.

[0029] Furthermore, the height detection system includes an infrared height sensor and a wire rope displacement sensor; the steps of using the height detection system to obtain the first height of the docking platform docked by the lifting and unloading platform and using the height detection system to obtain the second height of the lifting and unloading platform include;

[0030] Use the infrared height sensor to detect the first height;

[0031] Use the wire rope displacement sensor to detect the second height.

[0032] Different from the prior art, the hydraulic control system of the present application is applied to a lifting and unloading platform provided with a height detection system. The height detection system is used to detect the first height and the second height in real time. Based on the comparison result of the first height and the second height, the processor realizes precise control of the opening of the control oil circuit of the lifting cylinder, and further realizes precise control of the ascending or descending speed of the lifting and unloading platform, realizes precise docking of the lifting and unloading platform with the docking platform, ensures smooth ascending or descending of the lifting and unloading platform, and improves the loading and unloading efficiency.

[0033] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and do not limit the present application. Description of the Drawings

[0034] To more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the accompanying drawings required for the description of the embodiments. Obviously, the accompanying drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings.

[0035] Figure 1 It is a schematic flowchart of an embodiment of the control method of the hydraulic control system of the present application;

[0036] Figure 2 Is Figure 1 The first specific flowchart of steps S12 and S14 in

[0037] Figure 3 Is Figure 3 The specific flowchart of step S142 in

[0038] Figure 4 Is Figure 1 The second specific flowchart of steps S12 and S14 in

[0039] Figure 5 Is Figure 4 The specific flowchart of step S242 in

[0040] Figure 6 Is Figure 1 The specific flowchart of step S13 in

[0041] Figure 7 It is a circuit schematic diagram of an embodiment of the hydraulic control system of the lifting and unloading platform of the present application;

[0042] Figure 8 It is a structural schematic diagram of an embodiment of the lifting platform of the present application;

[0043] Reference numerals of the drawings:

[0044] 1 - Lifting and unloading platform; 2 - Hydraulic control system; 201 - Oil tank; 202 - Processor; 203 - Lifting cylinder; 204 - Lifting cylinder control oil circuit; 205 - Motor; 206 - Fixed displacement hydraulic pump; 207 - High pressure filter; 208 - Check valve; 209 - One-way electromagnetic directional control valve; 210 - Two-position four-way electromagnetic directional control valve; 211 - One-way electro-hydraulic throttle valve; 212 - Proportional speed control valve; 213 - Electromagnetic relief valve; 214 - Pressure gauge; 215 - Return oil filter; 216 - Manual valve; 3 - Height detection system; 31 - Infrared height sensor; 32 - Cable displacement sensor; 4 - Docking platform. Detailed implementation manners

[0045] To enable those skilled in the art to better understand the technical solution of the present application, the control method of the hydraulic control system provided by the present application will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It can be understood that the described embodiments are only a part of the embodiments of the present application, rather than all embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without creative efforts belong to the scope of protection of the present application.

[0046] The terms "first", "second", etc. in the present application are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "comprising" and "having" and any variations thereof are intended to cover non-exclusive inclusion. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally further includes steps or units not listed, or optionally further includes other steps or units inherent to these processes, methods, products or devices.

[0047] Since the existing lifting platforms have the following three disadvantages: First, the floating problem of the lifting platform during loading and unloading of goods, especially the difficulty in floating control on large-tonnage platforms; Second, the descending speed of the lifting platform cannot be automatically adjusted according to the load change, resulting in inconvenient operation and low efficiency; Third, the hydraulic system has large fluctuations during startup and shutdown, affecting the smoothness and safety of the operation of the lifting platform. Therefore, the present application provides a control method for a hydraulic control system. By a height detection device on the lifting and unloading platform, the first height and the second height are detected in real time, and the processor realizes precise control of the opening degree of the control oil circuit of the lifting cylinder according to the comparison result of the first height and the second height, and further realizes precise control of the ascending or descending speed of the lifting and unloading platform, realizes precise docking of the lifting and unloading platform with the docking platform, ensures the smooth ascending or descending of the lifting and unloading platform, and improves the loading and unloading efficiency. Please refer to Figure 1 , Figure 1 is a schematic flowchart of an embodiment of the control method of the hydraulic control system of the present application.

[0048] Among them, the execution subject of the control method of the hydraulic control system of the present application can be a hydraulic control system of a lifting and unloading platform. In some possible implementation manners, the control method of the hydraulic control system can also be implemented by the processor calling computer-readable instructions stored in the memory.

[0049] Specifically, as Figure 7 shown, the lifting and unloading platform 1 of this embodiment is used to dock with the docking platform 4 to load the goods on the docking platform 4 onto the lifting and unloading platform 1, or unload the goods on the lifting and unloading platform 1 onto the docking platform 4.

[0050] Among them, the lifting and unloading platform 1 is provided with a height detection system 3, which is used to obtain the height information of the lifting and unloading platform 1. The height information of this embodiment includes the first height of the docking platform 4 docked with the lifting and unloading platform 1, and the second height of the lifting and unloading platform 1.

[0051] Specifically, the height detection system 3 of this embodiment includes an infrared height sensor 31 and a pull rope displacement sensor 32. The infrared height sensor 31 is used to detect the first height, and the pull rope displacement sensor 32 is used to detect the second height. Among them, the infrared height sensor 31 is arranged on the side of the lifting and unloading platform 1 away from the ground, and extends outward to the air above the docking platform 4. The pull rope displacement sensor 32 is arranged on the side of the lifting and unloading platform 1 close to the ground, and is used to detect the distance between the two scissors, so as to realize the detection of the second height of the lifting and unloading platform 1.

[0052] The hydraulic control system 2 of this embodiment is specifically as follows Figure 8 As shown, the hydraulic control system 2 includes an oil tank 201, a processor 202, a lifting cylinder 203, a lifting cylinder control oil circuit 204, an electromagnetic overflow valve 213, a pressure gauge 214, an oil return filter 215 and a manual valve 216. The lifting cylinder control oil circuit 204 connects the lifting cylinder 203 and the oil tank 201, and the processor 202 is electrically connected to the lifting cylinder control oil circuit 204 and the height detection system 3; wherein the processor 202 controls the opening of the lifting cylinder control oil circuit 204 based on the comparison result between the first height and the second height to control the rising speed or the falling speed of the lifting and unloading platform 1.

[0053] Specifically, the lifting cylinder control oil circuit 204 includes a motor 205, a quantitative hydraulic pump 206, a high-pressure filter 207, a one-way valve 208, a one-way electromagnetic reversing valve 209, a two-position four-way electromagnetic reversing valve 210, a one-way electric proportional throttle valve 211 and a proportional speed control valve 212. The motor 205 is connected to a first end of the quantitative hydraulic pump 206, a second end of the quantitative hydraulic pump 206 is connected to the oil tank 201, a third end of the quantitative hydraulic pump 206 is connected to a first end of the high-pressure filter 207, a second end of the high-pressure filter 207 is connected to a first end of the one-way valve 208, a second end of the one-way valve 208 is connected to a first end of the one-way electromagnetic reversing valve 209 through a first branch, a first end of the one-way electromagnetic reversing valve 209 is further connected to the oil tank 201 through a second branch, and a second end of the one-way electromagnetic reversing valve 209 is connected to the lifting cylinder 203 through a third branch.

[0054] The first branch is provided with a two-position four-way electromagnetic directional valve 210. The first end of the two-position four-way electromagnetic directional valve 210 is connected to a check valve 208. The second end of the two-position four-way electromagnetic directional valve 210 is connected to the first end of a one-way electromagnetic directional valve 209. The third end of the two-position four-way electromagnetic directional valve 210 is left hanging. The fourth end of the one-way electromagnetic directional valve 209 is connected to an oil tank 201. The third branch is provided with a one-way electro-hydraulic proportional throttle valve 211. The first end of the one-way proportional throttle valve is connected to the second end of the one-way electromagnetic directional valve 209. The second end of the one-way proportional throttle valve is connected to a lifting oil cylinder 203. The second branch is provided with a proportional speed control valve 212. The first end of the proportional speed control valve 212 is connected to the second end of the two-position four-way electromagnetic directional valve 210 and the first end of the one-way electromagnetic directional valve 209. The second end of the proportional speed control valve 212 is connected to the oil tank 201.

[0055] The first end of an electromagnetic relief valve 213 is connected to the second end of a high-pressure filter 207 and the first end of the check valve 208. The second end of the electromagnetic relief valve 213 is connected to the oil tank 201. The electromagnetic relief valve 213 is used to set the system maximum pressure of the hydraulic control system 2 and act as the pilot pressure relief circuit of the entire hydraulic control system 2. A pressure gauge 214 is connected to the second end of the two-position four-way electromagnetic directional valve 210 and the first end of the one-way electromagnetic directional valve 209. The pressure gauge 214 is used to display the working pressure of the hydraulic control system 2. The first end of an oil return filter 215 is connected to the second end of the electromagnetic relief valve 213. The second end of the oil return filter 215 is connected to the oil tank 201. The first end of a manual valve 216 is connected to the lifting oil cylinder 203. The second end of the manual valve 216 is connected to the first end of the oil return filter 215. The manual valve 12 is used to lower the platform manually after a power outage or when the hydraulic control system 2 fails to operate.

[0056] Specifically, the control method of the hydraulic control system of the present disclosure embodiment may include the following steps:

[0057] Step S11: Obtain a start signal by using a processor.

[0058] Wherein, the start signal is used to start the operation of the hydraulic control system 2.

[0059] Step S12: Based on the start signal, control the hydraulic control system to boost pressure through the oil circuit of the lifting oil cylinder, and control the lifting oil cylinder to perform ascending or descending operations.

[0060] Wherein, in this embodiment, based on the start signal, by controlling the switching between the energized state and the de-energized state of the two-position four-way electromagnetic directional valve 8, the boosting and pressure relief of the hydraulic control system 2 are realized, and by controlling the opening degree of the proportional speed control valve 212 or the one-way proportional throttle valve 211, the ascending or descending operations of the lifting oil cylinder 203 are realized, and the ascending speed or descending speed of the lifting and unloading platform 1 is controlled.

[0061] Step S13: Use the height detection system to obtain the first height of the docking platform docked with the lifting and unloading platform, and use the height detection system to obtain the second height of the lifting and unloading platform.

[0062] Specifically, in this embodiment, the height detection system is used to obtain the first height of the docking platform docked with the lifting and unloading platform, and the height detection system is used to obtain the second height of the lifting and unloading platform, and the height information is transmitted to the processor 202.

[0063] Optionally, for the specific process of implementing the detection of the first height and the second height by the height detection system in this embodiment, please continue to refer to Figure 6 , Figure 6 Yes Figure 1 is the schematic diagram of the specific process of step S13 in

[0064] Step S131: Use the infrared height sensor to detect the first height.

[0065] Specifically, in this embodiment, the infrared height sensor 31 is used to detect the first height of the docking platform 4, which can be executed simultaneously with step S11.

[0066] Step S132: Use the wire rope displacement sensor to detect the second height.

[0067] Specifically, in this embodiment, the wire rope displacement sensor 32 is used to detect the second height of the lifting and unloading platform 1.

[0068] Step S14: Based on the comparison result of the first height and the second height, control the opening degree of the control oil circuit of the lifting cylinder to control the rising speed or the falling speed of the lifting and unloading platform.

[0069] Specifically, the processor 202 in this embodiment compares the first height and the second height obtained based on step S131 and step S132, and based on the comparison result, increases or decreases the opening degree of the control oil circuit 204 of the lifting cylinder to control the rising speed or the falling speed of the lifting and unloading platform 1.

[0070] Optionally, in one embodiment, the control method of the hydraulic control system 2 can be used to control the rising of the lifting and unloading platform 1. Please continue to refer to Figure 2 , Figure 2 Yes Figure 1 is the first schematic diagram of the specific process of step S12 and step S14 in

[0071] Step S121: In response to obtaining the start signal, control the two-position four-way electromagnetic directional valve to switch from the power-off state to the power-on state.

[0072] Among them, in response to the obtained start signal for the lifting and unloading platform 1 to rise, it is necessary to control the hydraulic control system 2 to start working, and the processor 202 controls the two-position four-way solenoid directional valve to switch from the power-off state to the power-on state.

[0073] Step 141: In response to the hydraulic control system boosting pressure, control the one-way solenoid directional valve to be powered on.

[0074] Among them, when the two-position four-way solenoid directional valve is in the power-on state and the hydraulic control system 2 boosts pressure, the processor 202 further controls the one-way solenoid directional valve 209 to be powered on, and the oil fluid can flow through the one-way solenoid directional valve 209 to the lifting cylinder 203.

[0075] Step 142: Based on the comparison result between the first height and the second height, use the processor to control the proportional speed control valve.

[0076] Among them, according to the comparison result between the first height obtained by the infrared height sensor 31 and the second height obtained by the rope displacement sensor 32, the processor 202 controls the proportional speed control valve 212 to adjust its opening degree.

[0077] Optionally, for the specific process of adjusting the opening degree of the proportional speed control valve 212, please continue to refer to Figure 3 , Figure 3 is Figure 3 the schematic diagram of the specific process of step S142 in. Specifically, it includes the following steps:

[0078] Step 1421: In response to the one-way solenoid directional valve being powered on, control the opening degree of the proportional speed control valve to decrease to a first preset value to control the rising speed of the lifting and unloading platform to increase to a first preset speed.

[0079] Among them, the processor 202 controls the opening degree of the proportional speed control valve 212 to decrease to a first preset value S1 to control the rising speed of the lifting and unloading platform 1 to increase to a first preset speed V1.

[0080] Step 1422: In response to the difference between the second height and the first height being less than a first threshold, control the opening degree of the single proportional speed control valve to increase from the first preset value to a second preset value to control the rising speed of the lifting and unloading platform to decrease from the first preset speed to a second preset speed.

[0081] Among them, the processor 202 receives the analog electrical signal fed back by the rope displacement sensor 32. When the lifting and unloading platform 1 rises to be close to the height of the docking platform 4, that is, the difference between the second height and the first height is less than the first threshold, the processor 202 controls the opening degree of the proportional speed control valve 212 to increase from the first preset value S1 to the second preset value S2 to control the rising speed of the lifting and unloading platform 1 to decrease from the first preset speed V1 to the second preset speed V2.

[0082] Step 1423: In response to the difference between the second height and the first height being equal to zero, control the two-position four-way solenoid directional control valve to switch from the energized state to the de-energized state, control the one-way solenoid directional control valve to be de-energized, and control the opening of the proportional speed control valve to increase from the second preset value to the maximum value.

[0083] Among them, the processor 202 receives the analog electrical signal fed back by the wire rope displacement sensor 32. When the lifting and unloading platform 1 is accurately docked with the docking platform 4, the processor 202 controls the two-position four-way solenoid directional control valve 210 to switch from the energized state to the de-energized state, controls the one-way solenoid directional control valve 209 to be de-energized, and controls the opening of the proportional speed control valve 212 to increase from the second preset value S2 to the maximum value.

[0084] Optionally, when the lifting and unloading platform 1 is lower than the docking platform 4 and floating control is required, steps such as step 121 - step S1423 can also be executed.

[0085] Optionally, in one embodiment, the control method of the hydraulic control system 2 can be used to control the descent of the lifting and unloading platform 1. Please continue to refer to Figure 4 , Figure 4 Yes Figure 1 is the second specific process schematic diagram of steps S12 and S14 in

[0086] Step S221: In response to obtaining the start signal, control the two-position four-way solenoid directional control valve to maintain the de-energized state.

[0087] Among them, in response to obtaining the start signal for the descent of the lifting and unloading platform 1, it is necessary to maintain the hydraulic control system 2 in a pressure-relieved state, and control the two-position four-way solenoid directional control valve 210 to maintain the de-energized state.

[0088] Step 241: Control the one-way solenoid directional control valve to be energized.

[0089] Among them, when the one-way solenoid directional control valve 209 is energized, the oil in the lifting cylinder 203 can flow out through the one-way solenoid directional control valve 209.

[0090] Step 242: Based on the comparison result between the first height and the second height, use the processor to control the one-way electro-hydraulic throttle valve.

[0091] Among them, according to the comparison result of the first height obtained by the infrared height sensor 31 and the second height obtained by the wire rope displacement sensor 32, the processor 202 controls the one-way electro-hydraulic throttle valve 211 to adjust its opening.

[0092] Optionally, for the specific process of adjusting the opening of the proportional speed control valve 212, please continue to refer to Figure 5 , Figure 5 Yes Figure 4Specific process schematic diagram of step S242 in [Chinese]. Specifically, it includes the following steps:

[0093] Step 2421: In response to the energization of the one-way electromagnetic directional valve, control the opening of the one-way electro-hydraulic proportional throttle valve to increase to a first set value to control the descending speed of the lifting and unloading platform to increase to a third preset speed.

[0094] Among them, the processor 202 controls the opening of the one-way electro-hydraulic proportional throttle valve 211 to increase to a first set value E1 to control the descending speed of the lifting and unloading platform 1 to increase to a third preset speed V3.

[0095] Step 2422: In response to the difference between the first height and the second height being greater than a second threshold and less than a third threshold, control the opening of the one-way electro-hydraulic proportional throttle valve to decrease from the first set value to a second set value to control the descending speed of the lifting and unloading platform to decrease from the third preset speed to a fourth preset speed.

[0096] Among them, the processor 202 receives the analog electrical signal fed back by the cable displacement sensor 32. When the lifting and unloading platform 1 descends to near the predetermined height, specifically, when approaching the ground, that is, the difference between the second height and the first height is greater than the second threshold and less than the third threshold, the processor 202 controls the opening of the one-way electro-hydraulic proportional throttle valve 211 to decrease from the first set value E1 to a second set value E2 to control the descending speed of the lifting and unloading platform 1 to decrease from the third preset speed V3 to a fourth preset speed V4.

[0097] Step 2423: In response to the difference between the second height and the first height being equal to the third threshold, control the one-way electromagnetic directional valve to cut off the power.

[0098] Among them, the processor 202 receives the analog electrical signal fed back by the cable displacement sensor 32. When the lifting and unloading platform 1 has descended to the predetermined height, the processor 202 controls the one-way electromagnetic directional valve 209 to cut off the power.

[0099] Optionally, when the lifting and unloading platform 1 is higher than the docking platform 4 and floating control is required, steps 221 - step S2423 can also be executed.

[0100] The above are only embodiments of the present application, and do not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the content of the specification and drawings of the present application, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present application by the same token.

Claims

1. A control method for a hydraulic control system, applied to the hydraulic control system of a lifting and unloading platform. The lifting and unloading platform is provided with a height detection system for obtaining the height information of the lifting and unloading platform. The hydraulic control system includes an oil tank, a processor, a lifting cylinder, and a lifting cylinder control oil circuit. The lifting cylinder control oil circuit connects the lifting cylinder and the oil tank. The processor is electrically connected to the lifting cylinder control oil circuit and the height detection system, and is characterized in that, Including: Obtaining a start signal by using the processor; Based on the start signal, controlling the hydraulic control system to boost pressure through the control oil circuit of the lifting oil cylinder, and controlling the lifting oil cylinder to perform ascending or descending operations; Obtaining a first height of a docking platform docked with the lifting unloading platform by using the height detection system, and obtaining a second height of the lifting unloading platform by using the height detection system; Based on a comparison result between the first height and the second height, controlling an opening degree of the control oil circuit of the lifting oil cylinder to control an ascending speed or a descending speed of the lifting unloading platform.

2. The control method of the hydraulic control system according to claim 1, characterized in that, The control oil circuit of the lifting oil cylinder includes a two-position four-way electromagnetic reversing valve; the step of controlling the hydraulic control system to boost pressure through the control oil circuit of the lifting oil cylinder and controlling the lifting oil cylinder to perform ascending or descending operations based on the start signal includes: In response to obtaining the start signal, controlling the two-position four-way electromagnetic reversing valve to switch from a power-off state to a power-on state.

3. The control method of the hydraulic control system according to claim 2, characterized in that The control oil circuit of the lifting oil cylinder includes a one-way electromagnetic reversing valve and a proportional speed control valve; the step of controlling an opening degree of the control oil circuit of the lifting oil cylinder based on a comparison result between the first height and the second height to control an ascending speed or a descending speed of the lifting unloading platform includes; In response to the hydraulic control system boosting pressure, controlling the one-way electromagnetic reversing valve to be powered on; Based on a comparison result between the first height and the second height, controlling the proportional speed control valve by using the processor.

4. The control method of the hydraulic control system according to claim 3, characterized in that, The step of controlling the proportional speed control valve by using the processor based on a comparison result between the first height and the second height includes: In response to the one-way electromagnetic reversing valve being powered on, controlling an opening degree of the proportional speed control valve to be reduced to a first preset value to control an ascending speed of the lifting unloading platform to increase to a first preset speed.

5. The control method of the hydraulic control system according to claim 4, characterized in that, The step of controlling the proportional speed control valve by using the processor based on a comparison result between the first height and the second height includes: In response to a difference between the second height and the first height being less than a first threshold, controlling an opening degree of the proportional speed control valve to increase from the first preset value to a second preset value to control an ascending speed of the lifting unloading platform to decrease from the first preset speed to a second preset speed; In response to a difference between the second height and the first height being equal to zero, controlling the two-position four-way electromagnetic reversing valve to switch from a power-on state to a power-off state, controlling the one-way electromagnetic reversing valve to be powered off, and controlling an opening degree of the proportional speed control valve to increase from the second preset value to a maximum value.

6. The control method of the hydraulic control system according to claim 1, characterized in that, The control oil circuit of the lifting oil cylinder includes a two-position four-way electromagnetic reversing valve; the step of controlling the hydraulic control system to boost pressure through the control oil circuit of the lifting oil cylinder and controlling the lifting oil cylinder to perform ascending or descending operations based on the start signal includes: In response to obtaining the start signal, controlling the two-position four-way electromagnetic reversing valve to maintain a power-off state.

7. The control method of the hydraulic control system according to claim 6, characterized in that, The lifting cylinder control oil circuit includes a one-way electromagnetic directional control valve and a one-way electro-hydraulic proportional throttle valve; the step of controlling the opening degree of the lifting cylinder control oil circuit based on the comparison result between the first height and the second height to control the rising speed or the falling speed of the lifting and unloading platform includes: Controlling the one-way electromagnetic directional control valve to be energized; Based on the comparison result between the first height and the second height, using the processor to control the one-way electro-hydraulic proportional throttle valve.

8. The control method of the hydraulic control system according to claim 7, characterized in that, The step of using the processor to control the one-way electro-hydraulic proportional throttle valve based on the comparison result between the first height and the second height includes: In response to the one-way electromagnetic directional control valve being energized, controlling the opening degree of the one-way electro-hydraulic proportional throttle valve to increase to a first set value to control the falling speed of the lifting and unloading platform to increase to a third preset speed.

9. The control method of the hydraulic control system according to claim 8, characterized in that The step of using the processor to control the one-way electro-hydraulic proportional throttle valve based on the comparison result between the first height and the second height includes: In response to the difference between the first height and the second height being greater than a second threshold and less than a third threshold, controlling the opening degree of the one-way electro-hydraulic proportional throttle valve to decrease from the first set value to a second set value to control the falling speed of the lifting and unloading platform to decrease from the third preset speed to a fourth preset speed; In response to the difference between the second height and the first height being equal to the third threshold, controlling the one-way electromagnetic directional control valve to be de-energized.

10. The control method of the hydraulic control system according to claim 1, characterized in that, The height detection system includes an infrared height sensor and a wire rope displacement sensor; the step of using the height detection system to obtain the first height of the docking platform docked by the lifting and unloading platform and using the height detection system to obtain the second height of the lifting and unloading platform includes: Using the infrared height sensor to detect the first height; Using the wire rope displacement sensor to detect the second height.

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