Folding arm frame control method and system, aerial work platform and storage medium

Abstract

The invention discloses a folding arm frame control method and system, an aerial work platform and a storage medium, and relates to the technical field of engineering machinery. The control method comprises the steps that the absolute angle of a folding arm and the telescopic length of a main arm are obtained; the current value of an oil cylinder oil return proportional valve is determined according to the absolute angle of the folding arm and the telescopic length of the main arm; and the action of an oil cylinder oil return proportional valve is controlled according to the current value, and variable control over the oil return amount of the boom oil cylinder is achieved. On the basis of not changing the electric / hydraulic hardware configuration of the existing working platform, the current value of the oil return proportional valve of the oil cylinder is determined through the detected real-time boom posture, then the hydraulic oil return quantity of the boom action oil cylinder is dynamically adjusted according to the current value, the stability of the boom in the action process is ensured, and the working efficiency is improved. And the luffing operation of the boom is safer.

Description

Technical Field

[0001] The present invention belongs to the technical field of engineering machinery, and in particular relates to a folding arm boom control method, system, aerial work platform and storage medium. Background Art

[0002] With the continuous enrichment of aerial work construction scenes, aerial work platforms with higher meter sections and more boom forms have emerged. On the articulated boom aerial work platform, the realization of the boom movement is currently still completed by the electro-hydraulic control system, but as the length of the boom increases, the smoothness of the boom movement is often affected by the boom posture and the temperature of the hydraulic oil. Therefore, how to deal with the impact of changes in boom deflection and electro-hydraulic control system load on boom control (such as jitter, impact, etc.) has become a technical problem that needs to be overcome for high-altitude articulated boom aerial work platforms. Among them, a boom length of more than 38 meters is defined as a high-meter boom, and a boom length of more than 46 meters is defined as an ultra-high-meter boom.

[0003] In the existing boom electro-hydraulic control technology, only the oil intake of the boom cylinder is controlled variable, while the oil return of the boom cylinder is controlled quantitatively. This means that relatively stable control of the boom (i.e., without impact and shaking) can only be achieved under certain conditions (such as a certain boom posture and a certain temperature range). Under other conditions, the boom stability control effect is poor and the adaptability is poor. At the same time, the influence of the hydraulic resistance caused by the hydraulic oil temperature on the smooth movement of the boom is not taken into account during the boom control process. Summary of the invention

[0004] The object of the present invention is to provide a folding arm boom control method, system, aerial work platform and storage medium to solve the problems that the existing boom electro-hydraulic control technology only adopts variable control for the oil intake of the boom cylinder, and adopts quantitative control for the oil return amount of the boom cylinder, resulting in poor boom stability control effect and poor adaptability under some conditions, and at least one of the problems that the hydraulic oil temperature affects the smooth movement of the boom.

[0005] The present invention solves the above technical problems through the following technical solutions: a folding arm boom control method, comprising:

[0006] Get the absolute angle of the folding arm and the telescopic length of the main arm;

[0007] Determine the current value of the oil cylinder return proportional valve according to the absolute angle of the folding arm and the telescopic length of the main arm;

[0008] The action of the oil return proportional valve of the oil cylinder is controlled according to the current value, so as to realize variable control of the oil return amount of the boom oil cylinder.

[0009] Further, the current value of the oil cylinder oil return proportional valve is determined according to the folding arm absolute angle and the main arm telescopic length, including:

[0010] If the folding arm absolute angle θ belongs to the first angle range and the main arm telescopic length L belongs to the first length range, the current value I of the oil cylinder return proportional valve is equal to the difference between the first initial current I1 and the current adjustment value △I;

[0011] If the folding arm absolute angle θ belongs to the first angle range and the main arm telescopic length L belongs to the second length range, the current value I of the oil cylinder return proportional valve is equal to the first initial current I1;

[0012] If the folding arm absolute angle θ belongs to the second angle range and the main arm telescopic length L belongs to the first length range, the current value I of the oil cylinder return proportional valve is equal to the difference between the second initial current I2 and the current adjustment value △I;

[0013] If the folding arm absolute angle θ belongs to the second angle range and the main arm telescopic length L belongs to the second length range, the current value I of the oil cylinder return proportional valve is equal to the second initial current I2;

[0014] Among them, the first angle range is [θ mid ,θ max ], the second angle range is [θ min ,θ mid ), the first length range is [L mid ,L max ], the second length range is [L min ,L mid ), θ max Indicates the maximum absolute angle of the folding arm, θ min Indicates the minimum absolute angle of the folding arm, θ mid Indicates the third angle range (θ min ,θ max ), L max Indicates the maximum telescopic length of the main boom, L min Indicates the minimum telescopic length of the main boom, L mid Indicates the third length range (L min ,L max ), the first initial current I1 is less than the second initial current I2.

[0015] Furthermore, before controlling the action of the oil cylinder oil return proportional valve according to the current value, the control method further includes:

[0016] Get hydraulic oil temperature;

[0017] Determine the final current value of the oil cylinder return proportional valve according to the hydraulic oil temperature and the current value;

[0018] The action of the oil return proportional valve of the oil cylinder is controlled according to the final current value.

[0019] Further, determining the final current value of the oil cylinder return proportional valve according to the hydraulic oil temperature and the current value includes:

[0020] Determining whether the hydraulic oil temperature is greater than or equal to a temperature threshold;

[0021] If yes, the final current value is equal to the product of the corresponding temperature compensation coefficient and the current value; if no, the final current value is equal to the current value;

[0022] Among them, when the absolute angle θ of the folded arm corresponding to the current value belongs to the first angle range, the temperature compensation coefficient is the first temperature compensation coefficient; when the absolute angle θ of the folded arm corresponding to the current value belongs to the second angle range, the temperature compensation coefficient is the second temperature compensation coefficient; the value range of the first temperature compensation coefficient and the second temperature compensation coefficient is (0,1).

[0023] Furthermore, before obtaining the absolute angle of the folding arm and the telescopic length of the main arm, the control method further includes:

[0024] Obtaining the operation type of the boom handle, and determining whether it is a folding boom boom luffing control according to the operation type;

[0025] When the operation type is folding arm boom amplitude control, the folding arm absolute angle and the main arm telescopic length are obtained.

[0026] Based on the same concept, the present invention provides a folding arm boom control system, comprising:

[0027] Angle detection unit, used to measure the absolute angle of the folding arm;

[0028] Length detection unit, used to measure the telescopic length of the main arm;

[0029] The control unit is used to determine the current value of the cylinder oil return proportional valve according to the absolute angle of the folding arm and the telescopic length of the main arm, and control the action of the cylinder oil return proportional valve according to the current value to realize variable control of the boom cylinder oil return amount.

[0030] Further, the control unit is used to determine the current value of the oil cylinder return proportional valve according to the absolute angle of the folding arm and the telescopic length of the main arm, specifically including:

[0031] Determine whether the folding arm absolute angle θ belongs to the first angle range or the second angle range, and determine whether the main arm telescopic length L belongs to the first length range or the second length range;

[0032] If the folding arm absolute angle θ belongs to the first angle range and the main arm telescopic length L belongs to the first length range, the current value I of the oil cylinder return proportional valve is equal to the difference between the first initial current I1 and the current adjustment value △I;

[0033] If the folding arm absolute angle θ belongs to the first angle range and the main arm telescopic length L belongs to the second length range, the current value I of the oil cylinder return proportional valve is equal to the first initial current I1;

[0034] If the folding arm absolute angle θ belongs to the second angle range and the main arm telescopic length L belongs to the first length range, the current value I of the oil cylinder return proportional valve is equal to the difference between the second initial current I2 and the current adjustment value △I;

[0035] If the folding arm absolute angle θ belongs to the second angle range and the main arm telescopic length L belongs to the second length range, the current value I of the oil cylinder return proportional valve is equal to the second initial current I2;

[0036] Among them, the first angle range is [θ mid ,θ max ], the second angle range is [θ min ,θ mid ), the first length range is [L mid ,L max ], the second length range is [L min ,L mid ), θ max Indicates the maximum absolute angle of the folding arm, θ min Indicates the minimum absolute angle of the folding arm, θ mid Indicates the third angle range (θ min ,θ max ), L max Indicates the maximum telescopic length of the main boom, L min Indicates the minimum telescopic length of the main boom, L mid Indicates the third length range (L min ,L max ), the first initial current I1 is less than the second initial current I2.

[0037] Further, the control system also includes a temperature detection unit for measuring the temperature of the hydraulic oil;

[0038] The control unit is further used to determine the final current value of the cylinder oil return proportional valve according to the hydraulic oil temperature and the current value, and then control the action of the cylinder oil return proportional valve according to the final current value.

[0039] Further, the control unit is used to determine the final current value of the cylinder oil return proportional valve according to the hydraulic oil temperature and the current value, specifically including:

[0040] Determining whether the hydraulic oil temperature is greater than or equal to a temperature threshold;

[0041] If yes, the final current value is equal to the product of the corresponding temperature compensation coefficient and the current value; if no, the final current value is equal to the current value;

[0042] Among them, when the absolute angle θ of the folded arm corresponding to the current value belongs to the first angle range, the temperature compensation coefficient is the first temperature compensation coefficient; when the absolute angle θ of the folded arm corresponding to the current value belongs to the second angle range, the temperature compensation coefficient is the second temperature compensation coefficient; the value range of the first temperature compensation coefficient and the second temperature compensation coefficient is (0,1).

[0043] Based on the same concept, the present invention also provides a boom-type aerial work platform, the work platform comprising the folding arm boom control system as described above.

[0044] Based on the same concept, the present invention also provides a computer-readable storage medium having a computer program / instruction stored thereon, which implements the steps of the folding arm boom control method as described above when the computer program / instruction is executed by a processor.

[0045] Beneficial Effects

[0046] Compared with the prior art, the advantages of the present invention are:

[0047] Without changing the electrical / hydraulic hardware configuration of the existing working platform, the present invention determines the current value of the cylinder oil return proportional valve by detecting the real-time boom posture (absolute angle of the folding arm and the telescopic length of the main arm), and then dynamically adjusts the hydraulic oil return amount of the boom action cylinder according to the current value, thereby ensuring the stability of the boom during the action process and making the boom amplitude change operation safer and more comfortable.

[0048] The present invention also determines the temperature compensation coefficient through the detected hydraulic oil temperature, dynamically adjusts the current value of the cylinder oil return proportional valve according to the temperature compensation coefficient to obtain the final current value, and then dynamically adjusts the hydraulic oil return amount of the boom action cylinder according to the final current value, thereby avoiding the influence of the hydraulic oil temperature on the smooth movement of the boom, and further ensuring the stability and adaptability of the boom amplitude change operation. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solution of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only one embodiment of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0050] Figure 1 is a flow chart of a folding arm boom control method according to an embodiment of the present invention;

[0051] Figure 2 is a flow chart for determining the final current value of the oil cylinder oil return proportional valve in an embodiment of the present invention;

[0052] Figure 3 It is a structural block diagram of a folding arm boom control system in an embodiment of the present invention. DETAILED DESCRIPTION

[0053] The following is a clear and complete description of the technical solutions in the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0054] The technical solution of the present application is described in detail with specific embodiments below. The following specific embodiments can be combined with each other, and the same or similar concepts or processes may not be described in detail in some embodiments.

[0055] like Figure 1 As shown, a folding arm boom control method provided by an embodiment of the present invention comprises the following steps:

[0056] Step 1: Get the operation type of the arm handle;

[0057] Step 2: Determine whether the boom handle operation is for folding boom luffing control according to the operation type; when the operation type is for folding boom luffing control, proceed to step 3;

[0058] Step 3: Obtain the absolute angle of the folding arm, the telescopic length of the main arm and the temperature of the hydraulic oil;

[0059] Step 4: Determine the current value of the oil cylinder return proportional valve according to the absolute angle of the folding arm and the telescopic length of the main arm;

[0060] Step 5: Determine the final current value of the oil cylinder return proportional valve according to the hydraulic oil temperature and the current value determined in step 4;

[0061] Step 6: Control the action of the oil cylinder return proportional valve according to the final current value determined in step 5 to achieve variable control of the oil return amount of the boom cylinder.

[0062] In a specific embodiment of the present invention, an angle detection unit (such as an angle sensor) is used to measure the absolute angle of the folding arm in real time, and the absolute angle of the folding arm refers to the angle between the folding arm and the horizontal plane; a length detection unit (such as a length sensor) is used to measure the telescopic length of the main arm in real time; and a temperature detection unit is used to measure the hydraulic oil temperature of the hydraulic control system in real time.

[0063] The absolute angle of the folding arm, the telescopic length of the main arm and the temperature of the hydraulic oil are the inducing factors that cause the vibration and impact of the boom movement. These factors are used as control factors to participate in the control of the return oil volume of the boom cylinder. When controlling the oil intake of the boom cylinder, the angle detection unit also measures the absolute angle of the main arm and the relative angle between the main arm and the folding arm in real time. The length detection unit also measures the telescopic length of the folding arm in real time. The absolute angle of the main arm, the relative angle between the main arm and the folding arm, and the telescopic length of the folding arm are used as control factors to participate in the control of the oil intake of the boom cylinder. The oil intake control of the boom cylinder is an existing technology and will not be repeated here. Through the variable control of the oil intake of the boom cylinder and the variable control of the oil return of the boom cylinder, the vibration and impact of the boom movement are reduced and the stability of the boom movement is improved.

[0064] In a specific embodiment of the present invention, Figure 2 As shown in the figure, the current value of the oil return proportional valve of the cylinder is determined according to the absolute angle of the folding arm and the telescopic length of the main arm, including:

[0065] If the absolute angle θ of the folding arm belongs to the first angle range [θ mid ,θ max ] and the main arm telescopic length L belongs to the first length range [L mid ,L max ], then the current value I of the oil cylinder return proportional valve is equal to the difference between the first initial current I1 and the current adjustment value △I;

[0066] If the absolute angle θ of the folding arm belongs to the first angle range [θ mid ,θ max ] and the main arm telescopic length L belongs to the second length range [L min ,L mid ), then the current value I of the oil cylinder return proportional valve is equal to the first initial current I1;

[0067] If the absolute angle θ of the folding arm belongs to the second angle range [θ min ,θ mid ) and the main arm telescopic length L belongs to the first length range [L mid ,L max ], then the current value I of the oil cylinder return proportional valve is equal to the difference between the second initial current I2 and the current adjustment value △I;

[0068] If the absolute angle θ of the folding arm belongs to the second angle range [θ min ,θ mid) and the main arm telescopic length L belongs to the second length range [L min ,L mid ), then the current value I of the oil cylinder return proportional valve is equal to the second initial current I2;

[0069] Among them, θ max Indicates the maximum absolute angle of the folding arm, θ min Indicates the minimum absolute angle of the folding arm, θ mid Indicates the third angle range (θ min ,θ max ), L max Indicates the maximum telescopic length of the main boom, L min Indicates the minimum telescopic length of the main boom, L mid Indicates the third length range (L min ,L max ), the first initial current I1 is less than the second initial current I2.

[0070] In a specific embodiment of the present invention, θ mid The determination process of θ is as follows: when the first initial current I1 and the second initial current I1 are constant, an index for measuring the jitter performance of the folding arm (such as vibration frequency and / or vibration amplitude) is measured. For a certain folding arm absolute angle, when the jitter performance changes significantly when the folding arm absolute angle is exceeded, the folding arm absolute angle is used as θ. mid In this embodiment, the maximum folding arm absolute angle θ max The minimum folding arm absolute angle is 75°. min is 0°, θ mid 30~45°. mid The determination process of θ mid The process of determining is similar and will not be elaborated here.

[0071] The larger the absolute angle of the folding arm, the greater the load. In order to make the folding arm start more smoothly (that is, the jitter is smaller), a smaller oil cylinder return oil proportional valve current is selected, so the first initial current I1 < the second initial current I2. The first initial current I1 and the second initial current I2 are set according to technical indicators (such as speed requirements). In this embodiment, the value range of the first initial current I1 and the second initial current I2 is 0 to 2A. The current adjustment value ΔI is to minimize the jitter of the folding arm while meeting the technical indicators. The current adjustment value ΔI is determined by measuring the indicators that measure the jitter performance of the folding arm. Under the current adjustment value ΔI, the folding arm jitter is minimized. In this embodiment, the value range of the current adjustment value ΔI is 30mA to 50mA.

[0072] In a specific embodiment of the present invention, Figure 2 As shown, the final current value I of the oil cylinder return proportional valve is determined according to the hydraulic oil temperature and current value I e, including:

[0073] Determine whether the hydraulic oil temperature T is greater than or equal to the temperature threshold T th ;

[0074] If so, the final current value I e is equal to the product of the corresponding temperature compensation coefficient and the current value I; if not, the final current value I e Equal to the current value I.

[0075] When I=I1-△I or I=I1, that is, the absolute angle θ of the folding arm corresponding to the current value I belongs to the first angle range, the temperature compensation coefficient is the first temperature compensation coefficient K1, T≥T th The final current value I e =K1×I;

[0076] When I=I2-△I or I=I2, that is, the absolute angle θ of the folding arm corresponding to the current value I belongs to the second angle range, the temperature compensation coefficient is the second temperature compensation coefficient K2, T≥T th The final current value I e =K2×I. In this embodiment, the value range of the first temperature compensation coefficient K1 and the second temperature compensation coefficient K2 is (0, 1).

[0077] The higher the temperature, the lower the viscosity coefficient of the hydraulic oil. In order to reduce the vibration, the first temperature compensation coefficient K1 or the second temperature compensation coefficient K2 is smaller, that is, closer to 0.

[0078] In the existing boom electro-hydraulic control technology, the current of the oil return proportional valve of the boom cylinder is I=I1 or I=I2; while the current of the oil return proportional valve of the boom cylinder obtained by the folding boom control method of the present invention is I e =I1, or I e =I1-△I, or I e =K1×(I1-△I), or I e =K1×I1, or I e =I2, or I e =I2-△I, or I e =K2×(I2-△I), or I e =K2×I2, different currents of the cylinder return oil proportional valves correspond to different boom postures, which makes the boom stability control effect better and the adaptability better.

[0079] Figure 3 FIG. 2 shows a structural block diagram of a folding arm boom control system according to an embodiment of the present invention. Figure 3 As shown, the folding arm boom control system provided by the present invention includes an angle detection unit, a length detection unit, a temperature detection unit, a boom operating handle, a control unit and a cylinder oil return proportional valve.

[0080] The angle detection unit is used to measure the absolute angle of the folding arm in real time; the length detection unit is used to measure the telescopic length of the main arm in real time; the temperature detection unit is used to measure the hydraulic oil temperature in real time; the boom operating handle is used to determine the operating direction and operating range of the boom in real time.

[0081] The control unit is used to determine the operation type according to the operation direction and operation amplitude of the boom. When the operation type is folding arm amplitude control, it receives the absolute angle of the folding arm measured by the angle detection unit, the telescopic length of the main arm measured by the length detection unit and the hydraulic oil temperature measured by the temperature detection unit, and determines the current value of the cylinder oil return proportional valve according to the absolute angle of the folding arm and the telescopic length of the main arm, determines the final current value of the cylinder oil return proportional valve according to the hydraulic oil temperature and the current value, and controls the action of the cylinder oil return proportional valve according to the final current value to realize the control of the oil return speed of the boom cylinder (main arm amplitude cylinder, telescopic cylinder).

[0082] In this embodiment, the control unit is a vehicle controller of the aerial work platform. The vehicle controller generates a PWM signal according to the calculated final current value of the oil cylinder return proportional valve. The PWM signal is loaded onto the coil of the oil cylinder return proportional valve. The coil generates a current drive signal. The current drive signal drives the valve core displacement of the oil cylinder return proportional valve. The larger the valve core opening, the larger the hydraulic oil displacement, and the faster the oil cylinder moves. Conversely, the smaller the valve core opening, the smaller the hydraulic oil displacement, and the slower the oil cylinder moves. The voltage at both ends of the coil of the oil cylinder return proportional valve is controlled by controlling the proportion of the PWM signal, thereby adjusting the size of the current drive signal to adjust the oil cylinder speed.

[0083] When the oil inlet amount of the boom cylinder is controlled, the actuator is the cylinder oil inlet proportional valve. The control unit generates a PWM signal according to the absolute angle of the main arm, the relative angle between the main arm and the folding arm, and the telescopic length of the folding arm. The action of the cylinder oil inlet proportional valve is controlled according to the PWM signal to achieve the control of the oil inlet speed of the boom cylinder (main arm luffing cylinder, telescopic cylinder). The variable control of the oil inlet amount of the boom cylinder is a prior art and will not be repeated here.

[0084] In a specific embodiment of the present invention, the actuator also includes a cylinder hydraulic switch valve, the boom amplitude variation includes two actions, up and down, and the boom extension and retraction includes two actions, extending and retracting. The control unit generates a DO control signal (switch level signal) according to the operating direction of the operating handle to drive the cylinder hydraulic switch valve to achieve the direction drive of the boom amplitude variation and extension and retraction.

[0085] The oil cylinder in the oil cylinder oil return proportional valve, the oil cylinder oil inlet proportional valve and the oil cylinder hydraulic switch valve of the present invention refers to a variable amplitude oil cylinder.

[0086] In some embodiments, the folding arm boom control system may be combined with features of any folding arm boom control method in the embodiments of the present application, and vice versa, which will not be elaborated here.

[0087] Although not shown, an embodiment of the present invention further provides a boom-type aerial work platform, the work platform including the folding arm boom control system in the embodiment of the present application.

[0088] Although not shown, an embodiment of the present invention further provides a computer-readable storage medium having a computer program / instruction stored thereon, which, when executed by a processor, implements the steps of the folding arm boom control method in the embodiment of the present application.

[0089] Readable storage media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer-readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer-readable media does not include temporary computer-readable media (transitory media), such as modulated data signals and carrier waves.

[0090] What is disclosed above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of changes or modifications within the technical scope disclosed in the present invention, which should be covered within the protection scope of the present invention.

Claims

1. A folding arm boom control method, characterized in that: The control method comprises: Get the absolute angle of the folding arm and the telescopic length of the main arm; Determine the current value of the oil return proportional valve of the oil cylinder according to the absolute angle of the folding arm and the telescopic length of the main arm; The action of the oil return proportional valve of the oil cylinder is controlled according to the current value, so as to realize variable control of the oil return amount of the boom oil cylinder.

2. The folding arm boom control method according to claim 1, characterized in that: The current value of the oil cylinder oil return proportional valve is determined according to the absolute angle of the folding arm and the telescopic length of the main arm, including: If the folding arm absolute angle θ belongs to the first angle range and the main arm telescopic length L belongs to the first length range, the current value I of the oil cylinder return proportional valve is equal to the difference between the first initial current I1 and the current adjustment value ΔI; If the folding arm absolute angle θ belongs to the first angle range and the main arm telescopic length L belongs to the second length range, the current value I of the oil cylinder return proportional valve is equal to the first initial current I1; If the folding arm absolute angle θ belongs to the second angle range and the main arm telescopic length L belongs to the first length range, the current value I of the oil cylinder return proportional valve is equal to the difference between the second initial current I2 and the current adjustment value ΔI; If the folding arm absolute angle θ belongs to the second angle range and the main arm telescopic length L belongs to the second length range, the current value I of the oil cylinder return proportional valve is equal to the second initial current I2; Among them, the first angle range is [θ mid ,θ max ], the second angle range is [θ min ,θ mid ), the first length range is [L mid ,L max ], the second length range is [L min ,L mid ), θ max Indicates the maximum absolute angle of the folding arm, θ min Indicates the minimum absolute angle of the folding arm, θ mid Indicates the third angle range (θ min ,θ max ), L max Indicates the maximum telescopic length of the main boom, L min Indicates the minimum telescopic length of the main boom, L mid Indicates the third length range (L min ,L max ), the first initial current I1 is less than the second initial current I2.

3. The folding arm boom control method according to claim 2, characterized in that: The maximum folding arm absolute angle θ max is 75°, the minimum folding arm absolute angle θ min is 0°, θ mid 30~45°; The first initial current I1 and the second initial current I2 have a value range of 0 to 2A.

4. The folding arm boom control method according to any one of claims 1 to 3, characterized in that: Before controlling the action of the oil cylinder oil return proportional valve according to the current value, the control method further includes: Get hydraulic oil temperature; Determine the final current value of the oil cylinder return proportional valve according to the hydraulic oil temperature and the current value; The action of the oil return proportional valve of the oil cylinder is controlled according to the final current value.

5. The folding arm boom control method according to claim 4, characterized in that: Determining a final current value of the oil cylinder return proportional valve according to the hydraulic oil temperature and the current value includes: Determining whether the hydraulic oil temperature is greater than or equal to a temperature threshold; If yes, the final current value is equal to the product of the corresponding temperature compensation coefficient and the current value; if no, the final current value is equal to the current value; Among them, when the absolute angle θ of the folded arm corresponding to the current value belongs to the first angle range, the temperature compensation coefficient is the first temperature compensation coefficient; when the absolute angle θ of the folded arm corresponding to the current value belongs to the second angle range, the temperature compensation coefficient is the second temperature compensation coefficient; the value range of the first temperature compensation coefficient and the second temperature compensation coefficient is (0,1).

6. The folding arm boom control method according to claim 1, characterized in that: Before obtaining the absolute angle of the folding arm and the telescopic length of the main arm, the control method further includes: Obtaining the operation type of the boom handle, and determining whether it is a folding boom boom luffing control according to the operation type; When the operation type is folding arm boom amplitude control, the folding arm absolute angle and the main arm telescopic length are obtained.

7. A folding arm boom control system, characterized in that: The control system comprises: Angle detection unit, used to measure the absolute angle of the folding arm; Length detection unit, used to measure the telescopic length of the main arm; The control unit is used to determine the current value of the cylinder oil return proportional valve according to the absolute angle of the folding arm and the telescopic length of the main arm, and control the action of the cylinder oil return proportional valve according to the current value to realize variable control of the boom cylinder oil return amount.

8. The folding arm boom control system according to claim 7, characterized in that: The control unit is used to determine the current value of the oil cylinder return proportional valve according to the absolute angle of the folding arm and the telescopic length of the main arm, specifically including: Determine whether the folding arm absolute angle θ belongs to the first angle range or the second angle range, and determine whether the main arm telescopic length L belongs to the first length range or the second length range; If the folding arm absolute angle θ belongs to the first angle range and the main arm telescopic length L belongs to the first length range, the current value I of the oil cylinder return proportional valve is equal to the difference between the first initial current I1 and the current adjustment value ΔI; If the folding arm absolute angle θ belongs to the first angle range and the main arm telescopic length L belongs to the second length range, the current value I of the oil cylinder return proportional valve is equal to the first initial current I1; If the folding arm absolute angle θ belongs to the second angle range and the main arm telescopic length L belongs to the first length range, the current value I of the oil cylinder return proportional valve is equal to the difference between the second initial current I2 and the current adjustment value ΔI; If the folding arm absolute angle θ belongs to the second angle range and the main arm telescopic length L belongs to the second length range, the current value I of the oil cylinder return proportional valve is equal to the second initial current I2; Among them, the first angle range is [θ mid ,θ max ], the second angle range is [θ min ,θ mid ), the first length range is [L mid ,L max ], the second length range is [L min ,L mid ), θ max Indicates the maximum absolute angle of the folding arm, θ min Indicates the minimum absolute angle of the folding arm, θ mid Indicates the third angle range (θ min ,θ max ), L max Indicates the maximum telescopic length of the main boom, L min Indicates the minimum telescopic length of the main boom, L mid Indicates the third length range (L min ,L max ), the first initial current I1 is less than the second initial current I2.

9. A boom-type aerial work platform, characterized in that: The working platform comprises a folding arm boom control system as claimed in claim 7 or 8.

10. A computer-readable storage medium having a computer program / instruction stored thereon, characterized in that: When the computer program / instructions are executed by a processor, the steps of the folding arm boom control method according to any one of claims 1 to 6 are implemented.

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