Load sensing system and aerial work platform

Abstract

The application discloses a load sensing system and an aerial work platform, and relates to the field of hydraulic systems, and aims to improve the responsiveness of system output. The load sensing system comprises a load sensing variable pump, an electric proportional overflow valve, an oil inlet oil path, an actuator, a main reversing valve, a valve pressure compensator, an Ls loading control valve, a first pressure detection element and a second pressure detection element. The load sensing variable pump comprises an oil outlet. The electric proportional overflow valve is connected with the load sensing variable pump. The oil inlet oil path is communicated with the oil outlet of the load sensing variable pump. The actuator is arranged between the oil inlet oil path and an oil return oil path. The main reversing valve comprises an oil inlet and a load feedback port. The main reversing valve is arranged between the oil inlet oil path, the oil return oil path and the actuator. The valve pressure compensator is communicated with the main reversing valve. The Ls loading control valve is connected with an Ls oil path and the oil return oil path. The first pressure detection element detects the oil inlet pressure of the main reversing valve. The second pressure detection element detects the pressure of the load feedback port. The controller is electrically connected with the first and second pressure detection elements and the electric proportional overflow valve, so as to control the opening degree of the electric proportional overflow valve according to the difference between the detected pressures.

Description

Technical Field

[0001] This invention relates to the field of hydraulic systems, and more specifically to a load-sensitive system and an aerial work platform. Background Technology

[0002] In the closed-center load-sensing system used in a series of boom aerial work platforms, the LS load-sensing system is composed of an integrated threaded cartridge valve group or multi-way valve with LS feedback hydraulic signal, a hydraulically controlled load-sensing variable pump (hydraulic pump) with LS control function, and the hydraulic pipeline connecting the two, in order to achieve the purpose of energy-saving control.

[0003] In the above system, the stability and response time of the LS pressure feedback signal are the key factors that determine the system performance. The LS feedback signal usually needs to be fed back to the hydraulic load sensitive variable pump (hydraulic pump) through a long pipeline.

[0004] The inventors have discovered that the existing technology has at least the following problems: due to the combined effects of pressure loss in long pipelines, the influence of air content on the elastic modulus of hydraulic oil in pipelines, and the influence of oil temperature and ambient temperature on the viscosity of hydraulic oil, it is difficult for the system to guarantee rapid response, stability and accuracy of output, which can easily lead to unstable pressure and flow output of the system, resulting in problems such as response lag and jitter in the actuator. Summary of the Invention

[0005] This invention proposes a load-sensitive system and an aerial work platform to improve the responsiveness, stability, and precise control performance of the system output.

[0006] This invention provides a load-sensitive system, comprising:

[0007] Load-sensitive variable pump, including the oil outlet;

[0008] An electro-proportional relief valve is connected to the load-sensitive variable pump to control the pressure and displacement of the load-sensitive variable pump;

[0009] The oil inlet circuit is connected to the oil outlet of the load-sensitive variable pump;

[0010] Return oil path;

[0011] An actuator is located between the oil inlet passage and the oil return passage;

[0012] The main directional valve includes an oil inlet and a load feedback port; the main directional valve is disposed between the oil inlet circuit, the oil return circuit and the actuator.

[0013] The downstream pressure compensator is connected to the main directional valve and is located downstream of the main directional valve.

[0014] Ls oil circuit;

[0015] Return oil path;

[0016] The Ls loading control valve is connected to the Ls oil circuit and the return oil circuit to control the loading and unloading of Ls pressure.

[0017] The first pressure sensing element is configured to detect the pressure of the oil inlet passage;

[0018] The second pressure sensing element is configured to detect the pressure at the load feedback port of the main directional valve; and

[0019] The controller is electrically connected to the first pressure sensing element, the second pressure sensing element, and the electro-proportional relief valve. The controller is configured to control the opening of the electro-proportional relief valve based on the pressure difference detected by the first pressure sensing element and the second pressure sensing element, so as to control the pressure and displacement of the outlet of the load-sensitive variable pump.

[0020] In some embodiments, the Ls loading control valve includes:

[0021] The first oil port is connected to the oil outlet of the downstream pressure compensator and also to the second pressure sensing element; and

[0022] The second oil port is connected to the oil outlet of the main directional valve and to the return oil circuit.

[0023] Specifically, when the Ls loading control valve is in the first valve position, the branch where the Ls loading control valve is located is disconnected; when the Ls loading control valve is in the second valve position, the branch where the Ls loading control valve is located is connected, and the oil inlet circuit and the oil return circuit are connected.

[0024] In some embodiments, the actuator includes: a luffing cylinder assembly, a telescopic cylinder assembly, and a slewing assembly;

[0025] The luffing cylinder assembly, the telescopic cylinder assembly, and the slewing assembly are arranged side by side between the oil inlet circuit and the oil return circuit; each of the luffing cylinder assembly, the telescopic cylinder assembly, and the slewing assembly is provided with a main directional valve and a downstream pressure compensator.

[0026] In some embodiments, the load-sensitive system further includes:

[0027] A shuttle valve is connected to the load feedback port of each of the main directional valves, and the shuttle valve is configured to use the maximum pressure of the load feedback port of each of the main directional valves as the load feedback pressure of the load-sensitive system.

[0028] In some embodiments, when the load-sensitive system is in standby mode, both the main directional valve and the Ls loading control valve are de-energized, and the operating pressure of the load-sensitive variable pump is less than a preset value.

[0029] In some embodiments, the preset value is 0.5 MPa.

[0030] In some embodiments, when the actuator is in operation, the Ls load control valve is energized, and the main directional valve is in the first valve position, the controller is configured to dynamically adjust the electro-proportional relief valve in real time based on the pressure difference detected by the first pressure sensing element and the second pressure sensing element, so that the pressure difference between the oil inlet of the main directional valve and the load feedback port of the main directional valve is a set value.

[0031] In some embodiments, the set value is adjustable in real time.

[0032] In some embodiments, the Ls loading control valve is a solenoid valve.

[0033] This invention also provides an aerial work platform, including the load-sensitive system provided by any of the technical solutions of this invention.

[0034] The load-sensitive system provided by the above technical solution offers a system based on a load-sensitive variable pump and a downstream compensated CAN bus multi-way valve. It eliminates the Ls load feedback oil circuit found in related technologies and uses voltage pressure signals for feedback control, significantly improving the system's output responsiveness, stability, and precise control performance. Simultaneously, it solves the flow saturation problem faced by upstream compensated systems, exhibiting excellent anti-flow saturation control performance. Attached Figure Description

[0035] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0036] Figure 1 This is a schematic diagram of the structure of a load-sensitive system provided in an embodiment of the present invention.

[0037] Figure label:

[0038] 1. Load-sensitive variable pump; 2. Electro-proportional relief valve; 3. Inlet oil circuit; 4. Return oil circuit; 5. Actuator; 6. Main directional valve; 7. Post-valve pressure compensator; 8. Ls loading control valve; 9. First pressure sensing element; 10. Second pressure sensing element; 12. High-pressure oil filter; 13. Suction oil filter; 14. Relief valve; 15. Pressure reducing valve; 16. Return oil filter; 17. Platform control valve assembly; 18. Ls oil circuit;

[0039] 11. Oil outlet;

[0040] 51. Luffing cylinder assembly; 52. Telescopic cylinder assembly; 53. Slewing assembly;

[0041] 61. Oil inlet; 62. Load feedback port;

[0042] 81. First oil port; 82. Second oil port. Detailed Implementation

[0043] The following is combined with Figure 1 The technical solution provided by this invention will be described in more detail below.

[0044] The inventors discovered through research that existing hydraulic systems for aerial work platforms, in terms of precise output control and energy efficiency, typically represent an LS load-sensitive system composed of a hydraulically controlled variable pump (hydraulic pump) and a pre-valve compensator. When the flow rate of the composite action operating system reaches saturation, this hydraulic system can only resolve the saturation problem through electronic flow sharing via the control program. The anti-saturation control logic requires pre-calculation and allocation of flow, resulting in limitations and complexity in the control process and unsatisfactory control performance. Furthermore, the pressure setpoint of the pre-valve pressure compensator is a fixed differential pressure that cannot be changed. Under the premise that different valve core displacements, valve openings, and pre-valve pressure differentials are adequately compensated, the output flow rate has a certain degree of certainty and accuracy. However, this certainty and accuracy are affected by the viscosity-temperature characteristics and pressure loss characteristics of the hydraulic fluid in long pipelines. When the actual differential pressure is lower than the pre-set differential pressure of the compensator, the CAN bus multi-way valve for pre-valve compensation will be unable to perform precise flow output control. Therefore, this invention proposes a load-sensitive system.

[0045] The load-sensitive system provided in this embodiment of the invention includes a load-sensitive variable pump 1, an electro-proportional relief valve 2, an inlet oil passage 3, a return oil passage 4, an actuator 5, a main directional valve 6, a downstream pressure compensator 7, an Ls loading control valve 8, a first pressure sensing element 9, a second pressure sensing element 10, an Ls oil passage 18, and a controller. The load-sensitive variable pump 1 includes an outlet 11 and an electro-proportional relief valve 2. The inlet oil passage 3 is connected to the outlet 11 of the load-sensitive variable pump 1. The actuator 5 is located between the inlet oil passage 3 and the return oil passage 4. The main directional valve 6 includes an inlet 61 and a load feedback port 62. The main directional valve 6 is located between the inlet oil passage 3, the return oil passage 4, and the actuator 5. The downstream pressure compensator 7 is connected to the main directional valve 6 and is located downstream of the main directional valve 6. The Ls loading control valve 8 is specifically a solenoid valve. The Ls loading control valve 8 is connected to the Ls oil circuit 18 and the return oil circuit 4 to control the loading or unloading of the Ls pressure. The Ls oil circuit 18 is used to provide feedback on the load pressure. The return oil circuit 4 is used to realize system oil return. The first pressure sensing element 9 is configured to detect the pressure of the inlet oil circuit 3. The second pressure sensing element 10 is configured to detect the pressure of the load feedback port 62 of the main directional valve 6. The controller is electrically connected to the first pressure sensing element 9, the second pressure sensing element 10, and the electro-proportional relief valve 2. The controller is configured to control the opening degree of the electro-proportional relief valve 2 based on the pressure difference detected by the first pressure sensing element and the second pressure sensing element 10, so as to control the pressure and displacement of the outlet 11 of the load-sensitive variable pump 1.

[0046] The load-sensitive variable pump 1 is specifically an electronically controlled pump. The load-sensitive variable pump 1 is controlled by an electro-proportional relief valve 2. The control signal for the electro-proportional relief valve 2 comes from the controller. The controller acquires the oil pressure detected by the first pressure sensing element 9 and the second pressure sensing element 10, and controls the opening degree of the electro-proportional relief valve 2 based on the pressure difference between the two. The pressure and displacement of the load-sensitive variable pump 1 are controlled by the opening degree of the electro-proportional relief valve 2.

[0047] Describing the flow direction of the oil, an oil suction filter 13 is connected upstream of the load-sensitive variable pump 1. A high-pressure filter 12 is installed downstream of the load-sensitive variable pump 1. The high-pressure filter 12 adopts an existing structure. The oil inlet passage 3 is located downstream of the high-pressure filter 12.

[0048] The oil inlet 61 of the main directional valve 6 is connected to the oil inlet circuit 3. The first pressure sensing element 9 is directly connected to the oil inlet circuit 3 to detect the pressure at the oil inlet 61 of the main directional valve 6. The first pressure sensing element 9 is, for example, a pressure sensor.

[0049] Depending on the operational requirements of the actuator, the main directional valve 6 has various optional structural forms. In some embodiments, the main directional valve 6 adopts a three-position six-way directional valve. Figure 1As shown, the first valve position of the main directional valve 6 is used to achieve one action of the actuator 5, such as extending; the second valve position of the main directional valve 6 is used to achieve another action of the actuator 5, such as retracting. The main directional valve 6 can be controlled by electro-proportional control, hydraulic pilot control, CAN bus control, etc. In this embodiment of the invention, CAN bus control is used.

[0050] The downstream pressure compensator 7 is installed at the oil outlet 11 of the main directional valve 6. The downstream pressure compensator 7 is used to convert the outlet pressure of the main directional valve 6 to the pressure of the load feedback port 62 of the main directional valve 6.

[0051] The load-sensitive system may include multiple main directional valves 6 and multiple downstream pressure compensators 7. The main directional valves 6 and downstream pressure compensators 7 are arranged in a one-to-one correspondence. All the main directional valves 6, all the downstream pressure compensators 7, and the CAN bus module together constitute a CAN bus multi-way valve. The CAN bus module includes an electronic circuit board, Hall displacement sensors, connectors, and a housing, etc. The CAN bus multi-way valve also includes a relief valve 14, a pressure reducing valve 15, etc.

[0052] By employing a downstream pressure compensator 7, the CAN bus multi-way valve in the load-sensitive system can be dynamically and in real-time preset and adjusted by the electronic control program. This significantly improves the stability and controllability of the differential pressure. The stability of the differential pressure ensures precise control of the flow output of the CAN bus multi-way valve, while the dynamic adjustment and controllability of the differential pressure can be dynamically matched with the valve opening in real time, further enhancing the system's energy efficiency. With the downstream compensator, the differential pressure of each working link in the CAN bus multi-way valve can be automatically adjusted under combined action flow saturation conditions, exhibiting excellent anti-flow saturation control performance under combined action conditions. Combined action refers to the simultaneous operation of multiple actuators 5.

[0053] In some embodiments, the actuator 5 includes a luffing cylinder assembly 51, a telescopic cylinder assembly 52, and a slewing assembly 53. The luffing cylinder assembly 51, the telescopic cylinder assembly 52, and the slewing assembly 53 are arranged side-by-side between the inlet oil passage 3 and the return oil passage 4. Each of the luffing cylinder assembly 51, the telescopic cylinder assembly 52, and the slewing assembly 53 is equipped with a main directional valve 6 and a downstream pressure compensator 7. At least two of the luffing cylinder assembly 51, the telescopic cylinder assembly 52, and the slewing assembly 53 operate simultaneously; this is referred to as a combined operation. The return oil passage 4 delivers oil to the oil tank via the return oil filter 16.

[0054] In some embodiments, the Ls loading control valve 8 includes a first port 81 and a second port 82. The first port 81 is connected to the outlet 11 of the downstream pressure compensator 7 and to the second pressure detection element 10. The second port 82 is connected to the outlet 11 of the main directional valve 6 and to the return oil passage 4. When the Ls loading control valve 8 is in the first valve position, the branch containing the Ls loading control valve 8 is disconnected; when the Ls loading control valve 8 is in the second valve position, the branch containing the Ls loading control valve 8 is connected, and the inlet oil passage 3 and the return oil passage 4 are connected. The Ls loading control valve 8 functions to disconnect and connect the inlet oil passage 3 and the return oil passage 4. When the inlet oil passage 3 and the return oil passage 4 are connected, no pressure is fed back to the second pressure detection element 10. When the inlet oil passage 3 and the return oil passage 4 are disconnected, the pressure at the load feedback port 62 of the main directional valve 6 can be normally fed back to the second pressure detection element 10.

[0055] In some embodiments, the load-sensitive system further includes a shuttle valve (not shown), which is connected to the load feedback port of each main directional valve 6. The shuttle valve is configured to use the maximum pressure at the load feedback port of each main directional valve 6 as the load feedback pressure of the load-sensitive system. The main directional valve 6 of the last working link of the CAN bus multi-way valve and the downstream pressure compensator 7 are connected to the platform control valve group 17 to control the platform control valve oil circuit.

[0056] The load-sensitive system provided by the above technical solution no longer requires the Ls pressure feedback oil circuit. The oil pressure at the inlet 61 of the main directional valve 6 is detected by the first pressure sensing element 9, while the pressure at the load feedback port 62 of the main directional valve 6 is detected by the second pressure sensing element 10. The pressure difference (referred to as "pressure difference") detected by the first pressure sensing element 9 and the second pressure sensing element 10 can accurately control the outlet pressure and displacement of the load-sensitive variable pump 1.

[0057] In some embodiments, the setting value can be adjusted in real time.

[0058] When the load-sensitive system is in standby mode, all solenoid valves of the load-sensitive system are de-energized, including the main directional valve 6. At this time, no pressure signal is fed back to the load-sensitive variable pump 1, which operates at near-zero pressure (less than a preset value, such as 0.5 MPa, which is the set standby pressure) and low flow rate (only used to maintain system leakage), thus improving the energy efficiency of the load-sensitive system in standby mode.

[0059] See Figure 1 In some embodiments, when the actuator 5 is in the working state, the Ls loading control valve 8 is energized, and the main directional valve 6 is in the first valve position, i.e. Figure 1The upper position is shown. At this time, the controller is configured to dynamically adjust the electro-proportional relief valve 2 in real time according to the pressure difference detected by the first pressure detection element 9 and the second pressure detection element 10, so that the pressure difference between the oil inlet 61 of the main directional valve 6 and the load feedback port 62 of the main directional valve 6 is a set value.

[0060] When actuator 5 needs to operate, i.e., when actuator 5 is in working state, such as when the boom luffing starts, the Ls load control valve 8 is energized. The main directional valve 6 switches to the first valve position under the control pressure of the pilot oil circuit. The Ls load pressure is converted into an electrical pressure signal by the second pressure sensor and fed back to the load-sensitive variable pump 1. The system synchronously detects the pressure entering the oil inlet 61 of the main directional valve 6 through the first pressure detection element 9. The PID algorithm is used to dynamically control and adjust the electro-proportional relief valve 2 in the load-sensitive variable pump 1 in real time to ensure the pressure difference Δp between the pressure output by the load-sensitive variable pump 1 to the oil inlet 61 (P port) of the main directional valve 6 and the load feedback port 62 (Ls port). Δp is the pressure difference between the oil inlet 61 (P port) of the main directional valve 6 and the load feedback port 62 (Ls port), i.e., the difference between the pressure detected by the first pressure detection element 9 and the second pressure detection element 10. The controller can dynamically preset and adjust Δp in real time according to the requirements of the control program.

[0061] By matching the valve opening degree of different main directional valves 6, the system achieves intelligent correspondence with different flow characteristic curves within the CAN bus multi-way valve, significantly improving the output controllability of the CAN bus multi-way valve.

[0062] At a certain set Δp value in the system, this Δp is a stable and constant difference, unaffected by the pressure loss of components such as the pipeline between the outlet of the load-sensitive variable pump 1 and the oil inlet 61 of the main directional valve 6, the high-pressure oil filter, and the viscosity and elasticity of the hydraulic oil. This significantly improves the output precision control of the CAN bus multi-way valve, enabling it to maintain a constant state of oil supply to the system at a certain preset value.

[0063] Taking the actuator 5 as the luffing cylinder assembly 51 as an example: After passing through the high-pressure oil filter, the hydraulic oil first reaches the first valve position of the main directional valve 6 inside the CAN bus multi-way valve. After passing through the downstream pressure compensator 7 of the main directional valve 6, it re-enters the main directional valve 6 and enters the rodless chamber of the luffing cylinder assembly through the first valve position of the main directional valve 6. The piston rod of the boom luffing cylinder extends, and the boom performs luffing lifting action.

[0064] This invention also provides an aerial work platform, including the load-sensitive system provided by any of the technical solutions of this invention.

[0065] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A load-sensitive system, characterized in that, include: A load-sensitive variable pump (1) includes an oil outlet (11). An electro-proportional relief valve (2) is connected to the load-sensitive variable pump (1) to control the pressure and displacement of the load-sensitive variable pump (1); The oil inlet passage (3) is connected to the oil outlet (11) of the load-sensitive variable pump (1); Return oil circuit (4); The actuator (5) is located between the oil inlet passage (3) and the oil return passage (4); The main directional valve (6) includes an oil inlet (61) and a load feedback port (62); the main directional valve (6) is located between the oil inlet circuit (3), the oil return circuit (4) and the actuator (5); The downstream pressure compensator (7) is connected to the main directional valve (6) and is located downstream of the main directional valve (6); Ls oil circuit (18); The Ls loading control valve (8) is connected to the Ls oil circuit (18) and the return oil circuit (4) to control the loading and unloading of Ls pressure; The first pressure sensing element (9) is configured to detect the pressure of the oil inlet passage (3); The second pressure sensing element (10) is configured to detect the pressure at the load feedback port (62) of the main directional valve (6); as well as The controller is electrically connected to the first pressure sensing element (9), the second pressure sensing element (10), and the electro-proportional relief valve (2); the controller is configured to control the opening of the electro-proportional relief valve (2) based on the pressure difference detected by the first pressure sensing element and the second pressure sensing element (10) in order to control the pressure and displacement of the outlet (11) of the load-sensitive variable pump (1); When the actuator (5) operates, the Ls load control valve (8) is energized, and the main directional valve (6) switches to the first valve position under the control pressure of the pilot oil circuit. The Ls load pressure is converted into an electric pressure signal by the second pressure detection element (10) and fed back to the load-sensitive variable pump (1). The system synchronously detects the pressure entering the inlet (61) of the main directional valve (6) through the first pressure detection element (9), and uses a PID algorithm to control the pressure in the load-sensitive variable pump (1). The proportional relief valve (2) is dynamically controlled and adjusted in real time to ensure the pressure difference Δp between the pressure output by the load-sensitive variable pump (1) to the oil inlet (61) of the main directional valve (6) and the load feedback port (62); Δp is the pressure difference between the oil inlet (61) of the main directional valve (6) and the load feedback port (62), that is, the difference between the pressure detected by the first pressure detection element (9) and the second pressure detection element (10). The controller adjusts Δp dynamically in real time according to the requirements of the control program.

2. The load-sensitive system according to claim 1, characterized in that, The Ls loading control valve (8) includes: The first oil port (81) is connected to the oil outlet (11) of the downstream pressure compensator (7) and to the second pressure sensing element (10); and The second oil port (82) is connected to the oil outlet (11) of the main reversing valve (6) and to the return oil circuit (4); When the Ls loading control valve (8) is in the first valve position, the branch where the Ls loading control valve (8) is located is disconnected; when the Ls loading control valve (8) is in the second valve position, the branch where the Ls loading control valve (8) is located is connected, and the oil inlet circuit (3) and the oil return circuit (4) are connected.

3. The load-sensitive system according to claim 1, characterized in that, The actuator (5) includes: a variable amplitude cylinder assembly (51), a telescopic cylinder assembly (52), and a slewing assembly (53); The luffing cylinder assembly (51), the telescopic cylinder assembly (52), and the slewing assembly (53) are arranged side by side between the oil inlet circuit (3) and the oil return circuit (4); each of the luffing cylinder assembly (51), the telescopic cylinder assembly (52), and the slewing assembly (53) is provided with a main directional valve (6) and a valve downstream pressure compensator (7).

4. The load-sensitive system according to claim 3, characterized in that, Also includes: The shuttle valve is connected to the load feedback port of each of the main directional valves (6), and the shuttle valve is configured to use the maximum pressure of the load feedback port of each of the main directional valves (6) as the load feedback pressure of the load-sensitive system.

5. The load-sensitive system according to claim 1, characterized in that, When the load-sensitive system is in standby mode, the main directional valve (6) and the Ls loading control valve (8) are both de-energized, and the working pressure of the load-sensitive variable pump (1) is less than the preset value.

6. The load-sensitive system according to claim 5, characterized in that, The preset value is 0.5 MPa.

7. The load-sensitive system according to claim 1, characterized in that, When the actuator (5) is in working state, the Ls loading control valve (8) is energized, and the main directional valve (6) is in the first valve position, the controller is configured to dynamically adjust the electro-proportional relief valve (2) in real time according to the pressure difference detected by the first pressure detection element (9) and the second pressure detection element (10), so that the pressure difference between the oil inlet (61) of the main directional valve (6) and the load feedback port (62) of the main directional valve (6) is a set value.

8. The load-sensitive system according to claim 7, characterized in that, The set value can be adjusted in real time.

9. The load-sensitive system according to claim 1, characterized in that, The Ls loading control valve (8) is a solenoid valve.

10. An aerial work platform, characterized in that, Includes the load-sensitive system as described in any one of claims 1 to 9.

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