Control method and control system of engineering machinery and telescopic arm thereof

Abstract

The present disclosure provides a control method and control system for an engineering machine and its telescopic arm. The control method includes: obtaining a real-time value P of the working pressure of the oil cylinder and a real-time value L of the extension length of the movable part of the oil cylinder relative to the fixed part when the telescopic arm is moving with load, and the oil cylinder is used to drive the telescopic arm to extend and retract; according to the real-time value L, obtaining a real-time value Pm of the threshold pressure of the oil cylinder, and the threshold pressure represents the maximum pressure that the oil cylinder is allowed to withstand; if the real-time value P is greater than or equal to the real-time value Pm, the movable part stops moving in the direction of driving the telescopic arm to extend. The control system includes: a driving device, including an oil cylinder; a pressure detection device, configured to obtain the real-time value P; a displacement detection device, configured to obtain the real-time value L; and a control device, configured to obtain the real-time value Pm according to the real-time value L, and if the real-time value P is greater than or equal to the real-time value Pm, the movable part stops moving in the direction of driving the telescopic arm to extend.

Description

Technical Field

[0001] The present disclosure relates to the field of engineering machinery, and in particular to a control method and a control system for an engineering machinery and a telescopic arm thereof. Background Art

[0002] As the scope of construction continues to expand, the application scenarios of mobile cranes have become more diverse. Various application scenarios, such as working in limited spaces such as inside factory buildings, avoiding obstacles, inserting lifting operations, and quickly switching arm length working conditions, all put forward strong demands on the crane's load-carrying telescopic performance.

[0003] On-load telescopic means that after the crane hook lifts the heavy object, the crane's telescopic arm is extended and retracted while the heavy object is off the ground. In the related technologies known to the inventor, the practical application of on-load telescopic technology still has limitations. Most cranes restrict the on-load telescopic action by judging that the actual lifting weight exceeds a certain allowable weight of the empty hook. Due to the lack of corresponding control strategies, operators can usually use a forced switch to open the on-load telescopic action permission, but this method has the safety risk of illegal operation; and for cranes with a given on-load telescopic performance table, the on-load telescopic capacity of the crane has not been fully utilized, making it difficult to promote further improvement of product performance and technical level. Summary of the invention

[0004] The purpose of the present disclosure is to provide a control method and a control system for an engineering machine and a telescopic arm thereof, so as to ensure the safety of operation and at the same time enable the load-carrying telescopic capacity of the telescopic arm to be fully utilized.

[0005] A first aspect of the present disclosure provides a control method for a telescopic arm of an engineering machine, comprising:

[0006] Acquire a real-time value P of the working pressure of the oil cylinder and a real-time value L of the extension length of the movable part of the oil cylinder relative to the fixed part when the telescopic arm is in a state of carrying load, wherein the oil cylinder is used to drive the telescopic arm to extend and retract;

[0007] According to the real-time value L of the extension length, a real-time value Pm of the threshold pressure of the oil cylinder corresponding to the real-time value L is obtained, wherein the threshold pressure represents the maximum pressure that the oil cylinder is allowed to withstand;

[0008] If the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, the movable component stops moving in the direction of driving the telescopic arm to extend.

[0009] According to some embodiments of the present disclosure, the step of obtaining the real-time value Pm of the threshold pressure of the oil cylinder according to the real-time value L of the extension length includes:

[0010] According to the real-time value L of the extension length, obtaining a real-time value L / Lm of the ratio of the extension length to the stroke Lm of the movable component;

[0011] According to the corresponding relationship between the ratio and the threshold pressure and the real-time value L / Lm of the ratio, the real-time value Pm of the threshold pressure corresponding to the real-time value L of the extension length is obtained.

[0012] According to some embodiments of the present disclosure, the further comprising:

[0013] Acquire a real-time value F of the tension of a cable connected between two different boom sections of the telescopic arm when the telescopic arm is in a state of carrying a load, wherein the cable is driven by the oil cylinder to make the two different boom sections relatively telescopic;

[0014] If the real-time value F of the pulling force is greater than or equal to the allowable pulling force Fm of the cable, the movable component is stopped from moving.

[0015] According to some embodiments of the present disclosure, it also includes: if the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, providing a first alarm information indicating that the telescopic arm is in an overload state.

[0016] According to some embodiments of the present disclosure, the method further includes: if the real-time value F of the tension is greater than or equal to the allowable tension Fm of the cable, providing a second alarm message indicating that the telescopic arm is in an overload state.

[0017] A second aspect of the present disclosure provides a control system for a telescopic arm of an engineering machine, comprising:

[0018] A driving device, comprising a cylinder for driving the telescopic arm to extend and retract;

[0019] A pressure detection device, configured to obtain a real-time value P of the working pressure of the oil cylinder when the telescopic arm is in a state of carrying a load;

[0020] a displacement detection device configured to obtain a real-time value L of the extension length of the movable part of the oil cylinder relative to the fixed part when the telescopic arm is in a state of carrying a load; and

[0021] The control device is connected to the pressure detection device and the displacement detection device by signal, and is configured to obtain the real-time value Pm of the threshold pressure of the cylinder corresponding to the real-time value L of the extension length according to the real-time value L, and the threshold pressure represents the maximum pressure that the cylinder is allowed to withstand. If the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, the movable part stops moving in the direction of driving the telescopic arm to extend.

[0022] According to some embodiments of the present disclosure, the control device is further configured to: obtain a real-time value L / Lm of the ratio of the extended length to the stroke Lm of the movable part based on the real-time value L of the extended length; and obtain a real-time value Pm of the threshold pressure corresponding to the real-time value L of the extended length based on the corresponding relationship between the ratio and the threshold pressure and the real-time value L / Lm of the ratio.

[0023] According to some embodiments of the present disclosure,

[0024] The telescopic arm comprises an arm section and a cable, wherein the cable is connected between two different arm sections, and the oil cylinder is drivingly connected to the cable to drive the two different arm sections to telescope relative to each other;

[0025] The control system also includes a tension detection device, which is configured to obtain a real-time value F of the tension of the cable when the telescopic arm is moving with load. The control device is connected to the signal of the tension detection device and is configured to stop the movement of the movable part if the real-time value F of the tension is greater than or equal to the allowable tension Fm of the cable.

[0026] According to some embodiments of the present disclosure, a display device is further included, which is signal-connected to the control device. The control device is configured to generate a first alarm message indicating that the telescopic arm is in an overload state if the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure. The display device is configured to display the working status information of the telescopic arm and / or the first alarm message.

[0027] According to some embodiments of the present disclosure, a display device is further included, which is signal-connected to the control device. The control device is configured to generate a second alarm message indicating that the telescopic arm is in an overload state if the real-time value F of the tension is greater than or equal to the allowable tension Fm of the cable. The display device is configured to display the working status information of the telescopic arm and / or the second alarm message.

[0028] A third aspect of the present disclosure provides an engineering machine, comprising the control system described in the second aspect of the present disclosure.

[0029] According to some embodiments of the present disclosure, the engineering machinery is a crane, and the telescopic arm is a lifting arm.

[0030] In the control method and control system of the engineering machinery and its telescopic arm provided by the present invention, the real-time value P of the working pressure of the cylinder and the real-time value L of the extension length of the movable part of the cylinder relative to the fixed part are used as the working state information of the telescopic arm, and the real-time value Pm of the threshold pressure of the cylinder is obtained according to the real-time value L of the extension length, and the load state of the cylinder is judged by the real-time value P of the working pressure of the cylinder and the real-time value Pm of the threshold pressure.

[0031] Since the threshold pressure changes with the extension length, the ultimate load that limits the load-bearing movement is also variable. When the telescopic arm is in load-bearing motion, as long as the real-time value P of the working pressure of the telescopic arm's cylinder is less than the real-time value Pm of the threshold pressure, the movement of the telescopic arm can be guaranteed to be safe, which is conducive to getting rid of the limitations of the data range of the performance table, expanding the applicable working conditions range of load-bearing telescopic operation, and giving full play to the load-bearing telescopic capacity of the telescopic arm.

[0032] In addition, by judging the load state of the oil cylinder through the real-time value P of the working pressure and the real-time value Pm of the threshold pressure, the instability of the oil cylinder caused by the jamming and obstruction of the telescopic arm during the loaded telescopic process can be prevented.

[0033] Other features and advantages of the present disclosure will become apparent from the following detailed description of exemplary embodiments of the present disclosure with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The drawings described herein are used to provide a further understanding of the present disclosure and constitute a part of the present application. The illustrative embodiments of the present disclosure and their descriptions are used to explain the present disclosure and do not constitute an improper limitation on the present disclosure. In the drawings:

[0035] Figure 1 The present invention is a flowchart of a control method for a telescopic arm according to some embodiments of the present invention.

[0036] Figure 2 The graph is a graph showing the ratio of the threshold pressure to the stroke of the moving part according to some embodiments of the present disclosure.

[0037] Figure 3 This is a schematic diagram of the control principle of the control system of the telescopic arm of some embodiments of the present disclosure.

[0038] Figures 1 to 3 In the figure, each reference numeral represents:

[0039] 1. Pressure detection device; 2. Displacement detection device; 3. Control device; 4. Display device; 5. Driving device. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present disclosure and its application or use. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0041] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, numerical expressions and numerical values ​​do not limit the scope of the present disclosure. At the same time, it should be understood that, for ease of description, the sizes of the various parts shown in the accompanying drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, these technologies, methods and equipment should be regarded as a part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as being merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once a certain item is defined in an accompanying drawing, it does not need to be further discussed in subsequent drawings.

[0042] In the description of the present disclosure, it should be understood that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present disclosure.

[0043] In the description of the present disclosure, it is necessary to understand that the orientation or positional relationship indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present disclosure and simplifying the description. Unless otherwise specified, these directional words 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, and therefore cannot be understood as limiting the scope of protection of the present disclosure; the directional words "inside and outside" refer to the inside and outside relative to the outline of each component itself.

[0044] In the process of realizing the present disclosure, the inventors found that in the related art, the telescopic arm's load-carrying telescopic action is usually limited according to pre-given performance data, such as the crane's lifting performance table. However, the data in the performance table is usually discrete data; outside the data range of the performance table, it is impossible to determine whether the telescopic arm can still safely carry out the telescopic movement with load. In this way, the telescopic arm's load-carrying telescopic performance cannot be maximized.

[0045] Moreover, if the telescopic arm of the construction machinery encounters unexpected situations such as getting stuck or blocked, the oil cylinder driving the telescopic arm may be pressurized, and the moving parts of the oil cylinder may be at risk of becoming unstable. It is difficult to effectively protect the safety of the oil cylinder by relying solely on safety protection devices such as torque limiters to limit the loaded telescopic action.

[0046] In order to improve the above-mentioned problem, the embodiments of the present disclosure provide a control method and a control device for a telescopic arm of an engineering machine, and an engineering machine that uses the control device to control the telescopic arm to extend and retract.

[0047] like Figure 1 As shown, some embodiments of the present disclosure provide a control method for a telescopic arm of an engineering machinery, including: obtaining a real-time value P of the working pressure of a cylinder and a real-time value L of an extension length of a movable part of the cylinder relative to a fixed part when the telescopic arm is moving with a load, the cylinder being used to drive the telescopic arm to extend and retract; according to the real-time value L of the extension length, obtaining a real-time value Pm of a threshold pressure of the cylinder corresponding to the real-time value L, the threshold pressure indicating the maximum pressure that the cylinder is allowed to withstand; if the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, stopping the movable part from moving in the direction of driving the telescopic arm to extend.

[0048] The control method of the telescopic arm provided in the embodiment of the present disclosure takes the real-time value P of the working pressure of the cylinder and the real-time value L of the extension length of the movable part of the cylinder relative to the fixed part as the working state information of the telescopic arm, and obtains the real-time value Pm of the threshold pressure of the cylinder according to the real-time value L of the extension length, and judges the load state of the cylinder through the real-time value P of the working pressure of the cylinder and the real-time value Pm of the threshold pressure.

[0049] Since the threshold pressure changes with the extension length, the ultimate load that limits the load-bearing movement is also variable. When the telescopic arm is in load-bearing motion, as long as the real-time value P of the working pressure of the telescopic arm's cylinder is less than the real-time value Pm of the threshold pressure, the movement of the telescopic arm can be guaranteed to be safe, which is conducive to getting rid of the limitations of the data range of the performance table, expanding the applicable working conditions range of load-bearing telescopic operation, and giving full play to the load-bearing telescopic capacity of the telescopic arm.

[0050] In addition, by judging the load state of the oil cylinder through the real-time value P of the working pressure and the real-time value Pm of the threshold pressure, the instability of the oil cylinder caused by the jamming and obstruction of the telescopic arm during the loaded telescopic process can be prevented.

[0051] The value of the threshold pressure is related to the extension length. In order to facilitate the application of the above control method to cylinders of different sizes on different telescopic arms, the corresponding relationship between the ratio of the extension length of the movable part of the cylinder to the stroke of the movable part and the threshold pressure can be obtained according to the structural characteristics of the cylinder through theoretical calculation or simulation calculation.

[0052] In some embodiments, the step of obtaining the real-time value Pm of the threshold pressure of the cylinder according to the real-time value L of the extension length includes: obtaining the real-time value L / Lm of the ratio of the extension length to the stroke Lm of the movable part according to the real-time value L of the extension length; obtaining the real-time value Pm of the threshold pressure corresponding to the real-time value L of the extension length according to the corresponding relationship between the ratio and the threshold pressure and the real-time value L / Lm of the ratio.

[0053] The corresponding relationship between the ratio and the threshold pressure can be represented by a curve or an expression. Figure 2 A graph showing the threshold pressure versus the ratio of the extension length of the movable component to the stroke according to some embodiments of the present disclosure is shown.

[0054] For a rope-type telescopic arm adopting a rope-type cable structure, the telescopic mechanism of the rope-type telescopic arm includes multiple arm sections, a cylinder, multiple cables, and multiple pulleys arranged corresponding to the cables. The cylinder body and piston rod of the cylinder are respectively connected to two adjacent arm sections, each pulley is relatively fixedly arranged at the end of one of the arm sections, the cable is wound around the pulley and the two ends are respectively connected to two different arm sections. When the cylinder body and piston rod of the cylinder are relatively telescopic, the arm sections are relatively telescopic driven by the cable. Therefore, for the above-mentioned telescopic arm, the tension of the cable is also an important factor to be considered whether the telescopic arm can be safely telescoped with load.

[0055] In some embodiments, the control method also includes: obtaining the real-time value F of the tension of the cable connected between two different arm sections of the telescopic arm when the telescopic arm is moving with load, the cable being driven by a cylinder to make the two different arm sections retract relative to each other; if the real-time value F of the tension is greater than or equal to the allowable tension Fm of the cable, the movable part stops moving.

[0056] That is to say, if the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, in order to avoid further increase in the working pressure of the cylinder, even if the real-time value F of the pulling force is smaller than the allowable pulling force Fm of the cable, the movable part is still stopped from moving in the direction of driving the telescopic arm to extend; if the real-time value F of the pulling force is greater than or equal to the allowable pulling force Fm of the cable, in order to avoid further increase in the pulling force of the cable, even if the real-time value P of the working pressure is smaller than the real-time value Pm of the threshold pressure, the movable part is still stopped from moving.

[0057] In this way, by obtaining the tension of the cable in real time, comparing the real-time value F of the tension with the allowable tension Fm of the cable, and then combining the real-time value P of the working pressure with the real-time value Pm of the threshold pressure, the safety of the loaded movement of the telescopic arm can be further guaranteed, and a more accurate allowable range of loaded telescopic movement can be provided.

[0058] In some embodiments, the control method further includes: if the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, providing a first alarm message indicating that the telescopic arm is in an overload state.

[0059] In some embodiments, the control method further includes: if the real-time value F of the pulling force is greater than or equal to the allowable pulling force Fm of the cable, providing a second alarm message indicating that the telescopic arm is in an overload state.

[0060] like Figure 3 As shown, some embodiments of the present disclosure also provide a control system for a telescopic arm of an engineering machinery, including a driving device 5, a pressure detection device 1, a displacement detection device 2 and a control device 3.

[0061] The driving device 5 comprises an oil cylinder for driving the telescopic arm to extend and retract.

[0062] In some embodiments, the driving device 5 may also include a hydraulic control valve for controlling the movement of the cylinder, an operating handle, and the like.

[0063] The pressure detection device 1 is configured to obtain a real-time value P of the working pressure of the cylinder when the telescopic arm is in a state of carrying a load.

[0064] The pressure detection device 1 can be directly arranged on the oil cylinder, or can be arranged in a hydraulic system for controlling the action of the oil cylinder, for example, between the main valve and the working oil port of the hydraulic cylinder.

[0065] The displacement detection device 2 is configured to obtain a real-time value L of the extension length of the movable part of the cylinder relative to the fixed part when the telescopic arm is in a state of carrying load and moving.

[0066] The displacement detection device 2 can be directly arranged on the oil cylinder, or on the arm section of the telescopic arm, or on any other position on the telescopic arm where the real-time value L of the extension length can be directly read or indirectly calculated.

[0067] The control device 3 is signal-connected with the pressure detection device 1 and the displacement detection device 2. The control device 3 is configured to obtain a real-time value Pm of the threshold pressure of the oil cylinder corresponding to the real-time value L according to the real-time value L of the extension length. The threshold pressure represents the maximum pressure that the oil cylinder is allowed to withstand. If the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, the movable part stops moving in the direction of driving the telescopic arm to extend.

[0068] The control device 3 can be provided separately or as part of the control device of the engineering machinery, for example, integrated into the torque limiter. The control device 3 is connected to the pressure detection device 1 and the displacement detection device 2 by signals, which can be connected by hard wire or by CAN (Controller Area Network) bus.

[0069] The control system of the telescopic arm provided in the embodiment of the present disclosure may be used to execute the control method of the telescopic arm provided in the embodiment of the present disclosure.

[0070] In the control system of the telescopic arm provided by the embodiment of the present disclosure, the real-time value P of the working pressure is obtained by the pressure detection device, and the real-time value L of the extension length is obtained by the displacement detection device as the working state information of the telescopic arm. The control device 3 obtains the real-time value Pm of the threshold pressure of the oil cylinder according to the real-time value L of the extension length, and judges the load state of the oil cylinder through the real-time value P of the working pressure of the oil cylinder and the real-time value Pm of the threshold pressure.

[0071] Since the threshold pressure changes with the extension length, the ultimate load that limits the load-bearing movement is also variable. When the telescopic arm is in load-bearing motion, as long as the real-time value P of the working pressure of the telescopic arm's cylinder is less than the real-time value Pm of the threshold pressure, the movement of the telescopic arm can be guaranteed to be safe, which is conducive to getting rid of the limitations of the data range of the performance table, expanding the applicable working conditions range of load-bearing telescopic operation, and giving full play to the load-bearing telescopic capacity of the telescopic arm.

[0072] In addition, by judging the load state of the oil cylinder through the real-time value P of the working pressure and the real-time value Pm of the threshold pressure, the instability of the oil cylinder caused by the jamming and obstruction of the telescopic arm during the loaded telescopic process can be prevented.

[0073] In some embodiments, the control device 3 is further configured to: obtain the real-time value L / Lm of the ratio of the extended length to the stroke Lm of the movable part based on the real-time value L of the extended length, and obtain the real-time value Pm of the threshold pressure corresponding to the real-time value L of the extended length based on the corresponding relationship between the ratio and the threshold pressure and the real-time value L / Lm of the ratio.

[0074] For telescopic arms that use a rope-and-cable structure, the tension of the cables is also an important factor to be considered in determining whether the telescopic arms can be safely extended and retracted with load. In some embodiments, the telescopic arms include arm sections and cables, the cables are connected between two different arm sections, and the oil cylinder is connected to the cable drive to drive the two different arm sections to retract and retract relative to each other. The control system also includes a tension detection device, which is configured to obtain a real-time value F of the tension of the cable when the telescopic arms are moving with load. The control device 3 is connected to the signal of the tension detection device and is configured to: if the real-time value F of the tension is greater than or equal to the allowable tension Fm of the cable, the movable part stops moving.

[0075] When the telescopic arm is in a state of being extended and retracted with load, the control device 3 obtains the tension of the cable in real time, compares and determines the real-time value F of the tension with the allowable tension Fm of the cable, and then combines the result of comparing and determining the real-time value P of the working pressure with the real-time value Pm of the threshold pressure. This can provide further protection for the safety of the loaded movement of the telescopic arm and provide a more accurate allowable range of loaded extension and retraction.

[0076] In some embodiments, Figure 3 As shown, the control system further includes a display device 4. The display device 4 is signal-connected to the control device 3, and the control device 3 is configured to generate a first alarm message indicating that the telescopic arm is in an overload state if the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure. The display device 4 is configured to display the working state information of the telescopic arm and / or the first alarm message.

[0077] In some embodiments, the control system further includes a display device 4. The display device 4 is connected to the control device 3 by signal, and the control device 3 is configured to generate a second alarm message indicating that the telescopic arm is in an overload state if the real-time value F of the tension is greater than or equal to the allowable tension Fm of the cable, and the display device 4 is configured to display the working state information of the telescopic arm and / or the second alarm message.

[0078] In some embodiments, the control device 3 described above can be implemented as a general processor, a programmable logic controller (PLC), a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components or any appropriate combination thereof for performing the functions described in the present disclosure.

[0079] Some embodiments of the present disclosure also provide an engineering machine, comprising the aforementioned control system. The engineering machine provided by the embodiments of the present disclosure has the advantages of the aforementioned control system due to the adoption of the aforementioned control system.

[0080] In some embodiments, the construction machinery is a crane, the telescopic arm is a lifting arm, and the aforementioned control system can be used to control the extension and retraction of the lifting arm under load.

[0081] In other embodiments, it may also be other engineering machinery with load-bearing telescopic requirements, such as engineering machinery with an aerial work platform.

[0082] Combine the following Figures 1 to 3 The control method of the telescopic arm of the control system provided based on some embodiments of the present disclosure is further described.

[0083] According to the structural characteristics of the oil cylinder, combined with the theoretical calculation method, the following Figure 2 A curve diagram of the threshold pressure-ratio of the extension length of the movable component to the stroke is shown, and the corresponding relationship reflected in the curve diagram is entered into the control device 3.

[0084] When the control system determines that the telescopic arm is in the loaded telescopic state, the real-time value P of the working pressure of the oil cylinder is obtained through the pressure detection device 1, and the pressure signal is transmitted to the control device 3. At the same time, the displacement detection device 2 obtains the real-time value L of the extension length of the movable part of the oil cylinder relative to the fixed part, and transmits the displacement signal to the control device 3. The control device 3 calculates the ratio L / Lm according to the stroke Lm of the oil cylinder, and obtains the real-time value Pm of the threshold pressure corresponding thereto.

[0085] When the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, the control device 3 generates a first alarm message indicating that the telescopic arm is in an overloaded state, and the display device 4 displays the first alarm message. At the same time, the control device 3 sends a control signal to the driving device 5 to stop the movable part from moving in the direction of driving the telescopic arm to extend, thereby limiting the telescopic action of the telescopic arm.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present disclosure rather than to limit it. Although the present disclosure has been described in detail with reference to the preferred embodiments, ordinary technicians in the relevant field should understand that the specific implementation methods of the present disclosure can still be modified or some technical features can be replaced by equivalents, which should all be included in the scope of the technical solution for protection requested by the present disclosure.

Claims

1. A control method for a telescopic arm of an engineering machinery, It is characterized in that include: Acquire a real-time value P of the working pressure of the oil cylinder and a real-time value L of the extension length of the movable part of the oil cylinder relative to the fixed part when the telescopic arm is in a state of carrying load, wherein the oil cylinder is used to drive the telescopic arm to extend and retract; According to the real-time value L of the extension length, a real-time value Pm of the threshold pressure of the oil cylinder corresponding to the real-time value L is obtained, wherein the threshold pressure represents the maximum pressure that the oil cylinder is allowed to withstand; If the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, the movable component stops moving in the direction of driving the telescopic arm to extend.

2. The control method according to claim 1, It is characterized in that The step of obtaining the real-time value Pm of the threshold pressure of the oil cylinder according to the real-time value L of the extension length comprises: According to the real-time value L of the extension length, obtaining a real-time value L / Lm of the ratio of the extension length to the stroke Lm of the movable component; According to the corresponding relationship between the ratio and the threshold pressure and the real-time value L / Lm of the ratio, the real-time value Pm of the threshold pressure corresponding to the real-time value L of the extension length is obtained.

3. The control method according to claim 1, It is characterized in that Also includes: Acquire a real-time value F of the tension of a cable connected between two different boom sections of the telescopic arm when the telescopic arm is in a state of carrying a load, wherein the cable is driven by the oil cylinder to make the two different boom sections relatively telescopic; If the real-time value F of the pulling force is greater than or equal to the allowable pulling force Fm of the cable, the movable component is stopped from moving.

4. The control method according to any one of claims 1 to 3, It is characterized in that Also includes: If the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, a first alarm message is provided to indicate that the telescopic arm is in an overload state.

5. The control method according to claim 3, It is characterized in that Also includes: If the real-time value F of the pulling force is greater than or equal to the allowable pulling force Fm of the cable, a second alarm message is provided to indicate that the telescopic arm is in an overload state.

6. A control system for a telescopic arm of an engineering machinery, It is characterized in that include: A driving device (5), comprising a cylinder for driving the telescopic arm to extend and retract; A pressure detection device (1) is configured to obtain a real-time value P of the working pressure of the oil cylinder when the telescopic arm is in a state of carrying a load; The displacement detection device (2) is configured to obtain a real-time value L of the extension length of the movable part of the oil cylinder relative to the fixed part when the telescopic arm is in a state of carrying a load; and The control device (3) is connected to the pressure detection device (1) and the displacement detection device (2) by signals, and is configured to obtain a real-time value Pm of a threshold pressure of the oil cylinder corresponding to the real-time value L according to the real-time value L of the extension length, wherein the threshold pressure represents the maximum pressure that the oil cylinder is allowed to withstand, and if the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, the movable component stops moving in the direction of driving the telescopic arm to extend.

7. The control system according to claim 6, It is characterized in that The control device (3) is further configured to: obtain a real-time value L / Lm of the ratio of the extended length to the stroke Lm of the movable component based on the real-time value L of the extended length, and obtain a real-time value Pm of the threshold pressure corresponding to the real-time value L of the extended length based on the corresponding relationship between the ratio and the threshold pressure and the real-time value L / Lm of the ratio.

8. The control system according to claim 6, It is characterized in that The telescopic arm comprises an arm section and a cable, wherein the cable is connected between two different arm sections, and the oil cylinder is drivingly connected to the cable to drive the two different arm sections to telescope relative to each other; The control system also includes a tension detection device, which is configured to obtain a real-time value F of the tension of the cable when the telescopic arm is in a state of carrying a load. The control device (3) is connected to the signal of the tension detection device and is configured to: if the real-time value F of the tension is greater than or equal to the allowable tension Fm of the cable, stop the movement of the movable component.

9. A control system according to any one of claims 6 to 8, It is characterized in that The invention also comprises a display device (4), wherein the display device (4) is connected to the control device (3) by signal, and the control device (3) is configured to generate a first alarm message indicating that the telescopic arm is in an overload state if the real-time value P of the working pressure is greater than or equal to the real-time value Pm of the threshold pressure, and the display device (4) is configured to display the working state information of the telescopic arm and / or the first alarm message.

10. The control system according to claim 8, It is characterized in that The device further comprises a display device (4), wherein the display device (4) is connected to the control device (3) by signal, and the control device is configured to generate a second alarm message indicating that the telescopic arm is in an overload state if the real-time value F of the tension is greater than or equal to the allowable tension Fm of the cable, and the display device (4) is configured to display the working state information of the telescopic arm and / or the second alarm message.

11. A construction machine, It is characterized in that Comprising a control system according to any one of claims 6 to 10.

12. The construction machine according to claim 11, It is characterized in that The engineering machinery is a crane, and the telescopic arm is a lifting arm.

Images