A platform leveling system based on boom deflection compensation

Abstract

The application discloses a platform leveling system based on arm frame deflection compensation, which comprises a rotary table, an arm frame, a platform, a luffing cylinder for driving the arm frame to luff and a hydraulic leveling system with compensation function; the arm frame is hinged to the rotary table, and the platform is hinged to the head of the arm frame; the hydraulic leveling system comprises a rotary table leveling cylinder hinged to the rotary table and the arm frame, a platform leveling cylinder hinged to the arm frame and the platform, a system valve arranged on the rotary table leveling cylinder, a balance valve arranged on the platform leveling cylinder and a hydraulic compensation subsystem; a first angle sensor and a length sensor are arranged at the tail of the arm frame, and a second angle sensor is arranged at the head of the arm frame; a third angle sensor is arranged at the platform; during the movement of the arm frame, deflection deflection angles are calculated according to the posture change of the arm frame, and the deflection deflection angles are compensated by using the hydraulic compensation subsystem. The application can ensure the reliability of the platform leveling and realize high-precision leveling in all working conditions and in full amplitude.

Description

Technical Field

[0001] This invention relates to the field of aerial work platform leveling technology, and in particular to a platform leveling system based on boom deflection compensation. Background Technology

[0002] Aerial work platforms are equipment used to transport people to work at heights. The leveling accuracy of the platform is extremely important. The leveling accuracy of the platform not only directly determines the safety of the operators, but also affects their comfort and stability. It is one of the core indicators of aerial work platforms.

[0003] Currently, the aerial work platform leveling system in the industry generally has three types: mechanical leveling, electric leveling, and hydraulic leveling. Each type of leveling has its own shortcomings.

[0004] The mechanical leveling mechanism relies on rigid linkage transmission, which cannot achieve extension and retraction. It can only be used for simple boom structures and has poor versatility.

[0005] Electrical leveling directly detects the platform's tilt angle and uses a controller to correct it directly. However, it cannot determine the cause of the tilt, nor can it identify whether it's a rigid tilt caused by boom luffing, a leveling delay due to excessively long piping, or a tilt caused by elastic impacts from the boom and platform themselves during movement. This can easily lead to excessive leveling during operation, causing severe shaking. Furthermore, the electrical control link has poor shock and interference resistance, posing a risk of leveling failure in the event of a malfunction, thus presenting a certain safety vulnerability.

[0006] Hydraulic leveling is the mainstream and preferred solution for aerial work platforms. Its core principle is to achieve a closed hydraulic circuit through the turntable leveling cylinder and the platform leveling cylinder. Through the geometric constraint relationship between the turntable boom and the boom platform, the platform angle and the boom luffing angle are synchronously linked in the opposite direction, ensuring that the platform angle relative to the ground is consistent. The hydraulic circuit has strong impact resistance, and with the addition of a balance valve, there is virtually no risk of failure. It has high leveling accuracy and is widely used in aerial work platforms.

[0007] However, with the increasing popularity of high-altitude aerial work platforms in recent years, the working range of these platforms has become increasingly larger. Under the influence of their own weight and concentrated forces at the front end, the boom experiences significant elastic bending deflection. Traditional hydrostatic leveling systems can only adjust the angle caused by the rigid changes in boom amplitude, without taking into account the platform tilt angle resulting from boom deflection. In some extreme working conditions with large amplitude and full boom extension, the boom deflection can even reach 7°, far exceeding the platform's permissible tilt value, posing a significant safety hazard. Traditional hydrostatic leveling systems can no longer meet the leveling requirements for such large-amplitude working conditions. Summary of the Invention

[0008] Purpose of the invention: The purpose of this invention is to provide a platform leveling system based on boom deflection compensation. While retaining the safety, impact resistance, and high stability of the hydrostatic leveling circuit lock-in, an independent hydraulic compensation subsystem is added. This subsystem can level and compensate for the platform tilt caused by boom deflection, correct the deflection angle caused by the elastic deformation of the boom, and achieve high-precision leveling under all working conditions and in all amplitudes.

[0009] Technical solution: A platform leveling system based on boom deflection compensation, including a turntable, boom, platform, a boom-driven hydraulic cylinder for boom luffing, and a hydraulic leveling system with compensation function;

[0010] The boom is hinged to the turntable, and the platform is hinged to the boom head;

[0011] The hydraulic leveling system includes a turntable leveling cylinder hinged to the turntable and the boom, a platform leveling cylinder hinged to the boom and the platform, a system valve on the turntable leveling cylinder, a balance valve on the platform leveling cylinder, and a hydraulic compensation subsystem.

[0012] A first angle sensor and a length sensor are arranged at the tail of the boom, and a second angle sensor is arranged at the head of the boom; the length sensor is used to detect the boom extension length, the first angle sensor is used to measure the angle at the tail of the boom, and the second angle sensor is used to measure the angle at the head of the boom; a third angle sensor is arranged at the platform to measure the platform tilt angle.

[0013] During boom movement, the tilt angle of the first angle sensor and the extension length of the length sensor are measured in real time to determine the boom posture change. The total deflection deviation angle α of the boom is calculated theoretically, and the boom deflection angle is compensated by the hydraulic compensation subsystem.

[0014] Furthermore, the hydraulic compensation subsystem calculates the amount of hydraulic oil compensation required for the platform leveling cylinder based on the total deflection deviation angle α of the boom.

[0015] Furthermore, the hydraulic compensation subsystem can be connected in parallel to the inlet of the balance valve or in parallel to the outlet of the balance valve, depending on the layout.

[0016] Furthermore, the outlet of the hydraulic compensation subsystem is connected to the rod chamber of the turntable leveling cylinder, the inlet of the balance valve, and the outlet of the system valve; the outlet of the hydraulic compensation subsystem is connected to the rodless chamber of the turntable leveling cylinder, the inlet of the balance valve, and the outlet of the system valve; the outlet of the balance valve is connected to the rod chamber of the platform leveling cylinder, and the outlet of the balance valve is connected to the rodless chamber of the platform leveling cylinder; the inlet of the system valve is connected to the main oil inlet, and the inlet is connected to the main oil return port.

[0017] Furthermore, the hydraulic compensation subsystem also includes a proportional valve, a check valve, a compensation pump, and a relief valve. The working port of the proportional valve is connected to the outlet of the hydraulic compensation subsystem. One end of the check valve is connected to the return port of the compensation pump and the inlet of the relief valve, and the other end is connected to the inlet of the proportional valve. The inlet of the compensation pump is connected to the inlet of the hydraulic compensation subsystem. The return port of the proportional valve is connected to the return port of the relief valve and the return port of the hydraulic compensation subsystem.

[0018] Furthermore, during the boom's movement, the tilt angle β of the third angle sensor is measured in real time. If β > 1°, it is determined that the platform angle is tilted. At this point, the difference between the first and second angle sensors is calculated. Based on the total deflection deviation angle α of the boom, determine whether there is a problem. If such a deviation exists, the hydraulic compensation subsystem will compensate for the deviation if the theoretically calculated deflection angle differs from the actual boom head and tail tilt angle.

[0019] Compared with the prior art, the significant advantages of this invention are as follows:

[0020] 1. This invention adds boom deflection and tilt angle compensation to the conventional hydraulic leveling system. By real-time detection and calculation of boom deflection changes, the hydrostatic circuit is compensated, ensuring the stability of the hydraulic leveling system. At the same time, the hydraulic leveling can still maintain high-precision leveling effect under large-amplitude conditions, unaffected by boom deflection. This ensures the reliability of platform leveling and achieves high-precision leveling under all working conditions and in all amplitudes.

[0021] 2. The boom deflection compensation angle of the present invention is based on the real-time detection of the boom posture and the formula fitting is performed. The compensation amount is set with a certain threshold, which makes up for the influence of boom deflection, while not affecting the effect of hydraulic leveling itself.

[0022] 3. This invention determines whether the deviation in leveling effect is caused by theoretical calculation deviation by comparing the difference between the angle sensors at the head and tail of the boom with the calculated deflection angle, based on the actual leveling effect at the detection platform. Then, it compensates for the deviation in theoretical calculation deflection by a certain deviation compensation.

[0023] 4. This invention is applicable to multi-section telescopic booms and hybrid booms. The boom deflection angle can be determined by the corresponding theoretical formula and detection method, and leveling compensation can be performed by the hydraulic compensation subsystem. Attached Figure Description

[0024] Figure 1 This is an isometric view of the platform leveling system of the present invention;

[0025] Figure 2 This is a schematic diagram of the boom deflection angle of the present invention;

[0026] Figure 3 This is a schematic diagram of the leveling hydraulic principle of the present invention;

[0027] Figure 4 This is a schematic diagram of the hydraulic compensation subsystem of the present invention;

[0028] Figure 5 This is a schematic diagram of the platform leveling cylinder installation of the present invention;

[0029] Figure 6 This is a control logic block diagram of the present invention;

[0030] In the diagram: 1-Turntable; 2-Turntable leveling cylinder; 3-Boom; 301-First angle sensor; 302-Length sensor; 303-Second angle sensor; 4-Platform leveling cylinder; 5-Platform; 501-Third angle sensor; 6-System valve; 7-Balance valve; 8-Hydraulic compensation subsystem; 801-Proportional valve; 802-Check valve; 803-Compensation pump; 804-Relief valve. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0032] like Figure 1 As shown, a platform leveling system based on boom deflection compensation includes a turntable 1, a boom 3 hinged to the turntable 1, a platform 5 hinged to the head of the boom 3, a boom cylinder for driving boom luffing, and a hydraulic leveling system with compensation function.

[0033] A first angle sensor 301 and a length sensor 302 are arranged at the tail of the boom, and a second angle sensor 303 is arranged at the head of the boom. The first angle sensor 301 is used to measure the angle at the tail of the boom, the length sensor 302 is used to detect the boom extension length, and the second angle sensor 303 is used to measure the angle at the head of the boom. A third angle sensor 501 is arranged at the platform to measure the platform tilt angle.

[0034] like Figure 1 , Figure 3 As shown, the hydraulic leveling system includes a turntable leveling cylinder 2 hinged to the turntable 1 and the boom 3, a platform leveling cylinder 4 hinged to the boom 3 and the platform 5, a system valve 6 on the turntable leveling cylinder 2, a balance valve 7 on the platform leveling cylinder 4, and a hydraulic compensation subsystem 8.

[0035] like Figure 3As shown, the outlet C5 of the hydraulic compensation subsystem 8 is connected to the rod chamber of the turntable leveling cylinder 2, the inlet V3 of the balance valve 7, and the outlet C1 of the system valve 6. The outlet C6 of the hydraulic compensation subsystem 8 is connected to the rodless chamber of the turntable leveling cylinder 2, the inlet V4 of the balance valve 7, and the outlet C2 of the system valve 6. The outlet C3 of the balance valve 7 is connected to the rod chamber of the platform leveling cylinder 4, and the outlet C4 of the balance valve 7 is connected to the rodless chamber of the platform leveling cylinder 4. The inlet V1 of the system valve 6 is connected to the main oil inlet P1, and the inlet V2 is connected to the main oil return port T1.

[0036] like Figure 4 As shown, the hydraulic compensation subsystem 8 includes a proportional valve 801, a check valve 802, a compensation pump 803, and a relief valve 804. The working port A of the proportional valve 801 is connected to the outlet C5 of the hydraulic compensation subsystem 8, and the working port B of the proportional valve 801 is connected to the outlet C6 of the hydraulic compensation subsystem 8. One end of the check valve 802 is connected to the return port of the compensation pump 803 and the inlet port of the relief valve 804, and the other end is connected to the inlet P2 of the proportional valve 801. The inlet port of the compensation pump 803 is connected to the inlet P3 of the hydraulic compensation subsystem 8. The return port T2 of the proportional valve 801 is connected to the return port of the relief valve and the return port T3 of the hydraulic compensation subsystem 8.

[0037] The specific control principle of this invention is as follows:

[0038] Taking a seven-section telescopic boom as an example, the boom's luffing angle and extension length can be detected in real time using the first angle sensor 301 and the length sensor 302. Based on the detection data, the platform tilt angle caused by the boom deflection can be calculated. Figure 2 As shown.

[0039] Boom 3 is a cantilever beam structure. The boom deflection angle generally includes the deflection angle caused by its own weight, the deflection angle caused by concentrated force, and the deflection angle caused by the forward bending moment. The formula for calculating the deflection angle θ of a single boom section is:

[0040] ,

[0041] Where E is the elastic modulus of the boom structure. Let F be the moment of inertia of the boom section, given the boom section dimensions and material. E and I are also known quantities. F is the concentrated force, q is the uniformly distributed load, M is the bending moment at the front of the boom, and L is the cantilever length of a single boom section. The concentrated force F, uniformly distributed load q, bending moment M, and cantilever length L are all variables related to the boom luffing angle and extension length, and can all be solved conventionally.

[0042] Therefore, the total deflection deviation angle of the seven-section telescopic boom is:

[0043] ,

[0044] Wherein, α is the theoretically calculated deflection angle value under the overall boom detection state. Based on the change of α, the proportional valve 801 is controlled to quantitatively compensate the platform leveling cylinder 4. The change in platform tilt angle caused by boom deflection is brought into the length difference calculation formula before and after platform leveling cylinder compensation to perform platform compensation and leveling.

[0045] In this embodiment, the hydraulic oil volume V required to compensate for the deflection angle can be determined based on the actual arrangement dimensions of the leveling hinge points, such as... Figure 5 For example, the calculation expression is as follows:

[0046] ,

[0047] Where L1 is the length after EF compensation, L2 is the length before EF compensation, EF is the total length of the platform leveling cylinder in working state; A is the cross-sectional area of ​​the cylinder cavity, the selection of which is determined based on the actual layout. Figure 5 As shown, the formulas for calculating L1 and L2 are as follows:

[0048] ,

[0049] ,

[0050] Among them, L DE Let L be the length of DE. Df Let DF be the length, and ∠EDF be the angle between DE and DF. If L1 > L2, then A is the cross-sectional area of ​​the rodless cavity; otherwise, it is the cross-sectional area of ​​the rod-mounted cavity. During the luffing motion of boom 3, the tilt angle of the first angle sensor 301 at the tail of the boom is detected in real time as γ1, the tilt angle of the second angle sensor 303 at the head of the boom is as γ2, and the tilt angle of the third angle sensor 501 at the platform is as β. The difference between the first angle sensor 301 at the tail of the boom and the second angle sensor 303 at the head of the boom is... , This represents the deflection angle caused by the actual deflection of the boom.

[0051] like Figure 6 As shown, if the platform tilt angle β > 1° during boom movement, it indicates that the platform is tilted relative to the ground. At this point, it needs to be determined whether... If such a deviation exists, it proves that there is a discrepancy between the theoretically calculated deflection angle and the actual boom head and tail tilt angles. In this case, compensation will continue through the hydraulic compensation subsystem 8, based on the platform tilt angle β and the difference. The smaller of the two values ​​determines the compensation amount, and the calculation method for the compensation oil amount is the same as that for conventional compensation.

Claims

1. A platform leveling system based on boom deflection compensation, characterized in that, Includes a turntable (1), a boom (3), a platform (5), a boom-driven hydraulic cylinder for boom luffing, and a hydraulic leveling system with compensation function; The boom (3) is hinged to the turntable (1), and the platform (5) is hinged to the boom head; The hydraulic leveling system includes a turntable leveling cylinder (2) hinged on the turntable (1) and the boom (3), a platform leveling cylinder (4) hinged on the boom (3) and the platform (5), a system valve (6) provided on the turntable leveling cylinder (2), a balance valve (7) provided on the platform leveling cylinder (4), and a hydraulic compensation subsystem (8). A first angle sensor (301) and a length sensor (302) are arranged at the tail of the boom, and a second angle sensor (303) is arranged at the head of the boom; the length sensor (302) is used to detect the extension length of the boom, the first angle sensor (301) is used to measure the angle of the tail of the boom, and the second angle sensor (303) is used to measure the angle of the head of the boom; a third angle sensor (501) is arranged at the platform to measure the tilt angle of the platform; During the movement of the boom (3), the tilt angle of the first angle sensor (301) and the stretch length of the length sensor are measured in real time to determine the change in boom posture. The total deflection deviation angle α of the boom is calculated theoretically, and the deflection angle compensation of the boom (3) is performed through the hydraulic compensation subsystem (8).

2. The platform leveling system based on boom deflection compensation according to claim 1, characterized in that, The hydraulic compensation subsystem (8) calculates the amount of hydraulic oil compensation required for the platform leveling cylinder (4) based on the total deflection deviation angle α of the boom.

3. The platform leveling system based on boom deflection compensation according to claim 1, characterized in that, The hydraulic compensation subsystem (8) is connected in parallel to the inlet of the balance valve (7) or in parallel to the outlet of the balance valve (7) depending on the layout.

4. The platform leveling system based on boom deflection compensation according to claim 1, characterized in that, The outlet (C5) of the hydraulic compensation subsystem is connected to the rod chamber of the turntable leveling cylinder, the inlet (V3) of the balance valve, and the outlet (C1) of the system valve. The outlet (C6) of the hydraulic compensation subsystem is connected to the rodless chamber of the turntable leveling cylinder, the inlet (V4) of the balance valve, and the outlet (C2) of the system valve. The outlet (C3) of the balance valve is connected to the rod chamber of the platform leveling cylinder, and the outlet (C4) of the balance valve is connected to the rodless chamber of the platform leveling cylinder. The inlet (V1) of the system valve is connected to the main oil inlet (P1), and the inlet (V2) is connected to the main oil return port (T1).

5. The platform leveling system based on boom deflection compensation according to claim 4, characterized in that, The hydraulic compensation subsystem (8) also includes a proportional valve (801), a check valve (802), a compensation pump (803), and a relief valve (804). The working port (A) of the proportional valve is connected to the outlet (C5) of the hydraulic compensation subsystem, and the working port (B) of the proportional valve is connected to the outlet (C6) of the hydraulic compensation subsystem. One end of the check valve (802) is connected to the return port of the compensation pump (803) and the inlet of the relief valve (804), and the other end is connected to the inlet (P2) of the proportional valve (801). The inlet of the compensation pump (803) is connected to the inlet (P3) of the hydraulic compensation subsystem. The return port (T2) of the proportional valve (801) is connected to the return port of the relief valve (804) and the return port (T3) of the hydraulic compensation subsystem (8).

6. The platform leveling system based on boom deflection compensation according to any one of claims 1-5, characterized in that, During the movement of the boom (3), the tilt angle β of the third angle sensor (501) is measured in real time. If β > 1°, it is determined that the platform angle is tilted. At this time, the difference between the first angle sensor (301) and the second angle sensor (303) is calculated. Based on the total deflection deviation angle α of the boom (3), determine whether there is a problem. If such deviation exists, the hydraulic compensation subsystem (8) will compensate for the deviation if there is a discrepancy between the theoretically calculated deflection angle and the actual boom head and tail tilt angle.

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