Forklift rollover prediction method and system and forklift

Abstract

The invention provides a forklift rollover prediction method and system and a forklift, and the method comprises the following steps: detecting the posture state of a forklift portal in real time, and obtaining the inclination angle of the portal when the portal inclines; the acting force of an inclined oil cylinder connected between the portal and the forklift body is obtained; actual tipping moment is obtained according to the acting force of the inclined oil cylinder and the inclination angle of the portal frame; obtaining the self-weight moment of the portal according to the inclination angle of the portal; a longitudinal stability coefficient is obtained according to the actual tipping moment, the self-weight moment of the portal and the built-in longitudinal stabilizing moment, and when the longitudinal stability coefficient exceeds a set threshold value, an early warning is given out.

Description

Technical Field

[0001] The present application relates to the technical field of forklifts, and in particular to a forklift rollover prediction method, system and forklift. Background Art

[0002] As an indispensable tool for material handling and efficient loading and unloading in today's industrial and logistics fields, forklifts are of great importance. However, in busy work scenarios, longitudinal tipping accidents caused by insufficient longitudinal stability have become a safety hazard that cannot be ignored. The main reason for such accidents is that the forklift lacks a corresponding prediction system. When the longitudinal stability coefficient of the forklift approaches the critical value, the forklift's balance state will become extremely fragile when the forklift is overloaded, the driving speed is inappropriate, or the ground conditions are poor. It is very easy to cause tipping, which in turn causes serious consequences such as equipment damage and even casualties.

[0003] In the prior art, a Chinese patent (CN101659386A) discloses a real-time monitoring method for the stability of a counterbalanced forklift. The method uses a sensor to collect the rear axle load in real time and monitors the percentage of the rear axle load in the weight of the whole machine to judge the stability of the whole machine. This solution only judges the stability by the proportion of the rear axle load, ignoring other factors that affect the stability. This solution also cannot obtain the overturning moment of the load during operation, and cannot quantify and calculate the longitudinal stability coefficient of the whole machine in real time. Therefore, this solution has the disadvantages of low detection accuracy and single applicable working conditions. Summary of the invention

[0004] In order to solve the technical problems existing in the prior art, the first aspect of the present application provides a forklift rollover prediction method, comprising the following steps: Detect the posture status of the forklift mast in real time and obtain the mast's tilt angle when the mast tilts; Obtain the force of the tilt cylinder connected between the mast and the forklift body; The actual tipping moment is obtained according to the force of the tilt cylinder and the tilt angle of the mast; Obtain the self-weight moment of the gantry according to the inclination angle of the gantry; The longitudinal stability coefficient is obtained based on the actual overturning moment, the mast's deadweight moment and the built-in longitudinal stability moment, and an early warning is issued when the longitudinal stability coefficient exceeds the set threshold.

[0005] Furthermore, the longitudinal stability coefficient is obtained using the following formula: K=(M2-M1) / M0, where K is the longitudinal stability coefficient, M0 is the longitudinal stability moment, M1 is the mast deadweight moment, and M2 is the actual tipping moment; where the longitudinal stability moment is the product of the rear axle load and the forklift wheelbase when unloaded.

[0006] Further, obtaining the actual tipping moment according to the force of the tilt cylinder and the tilt angle of the mast comprises: The tilt cylinder force is obtained according to the hydraulic oil pressure of the tilt cylinder, the tilt cylinder and the piston rod scale; Obtain the force arm of the tilt cylinder according to the tilt angle of the gantry; The actual tipping moment is obtained according to the tilt cylinder force and the lever arm of the tilt cylinder force.

[0007] Further, the method of obtaining the force arm of the tilt cylinder according to the tilt angle of the gantry includes: The moving coordinates of the hinge point A between the gantry and the tilt cylinder are obtained through the tilt angle of the gantry. The vertical distance from the front axle center O to the tilt cylinder, that is, the force arm of the tilt cylinder force, is obtained through the moving coordinates of the door frame and the hinge point A of the tilt cylinder.

[0008] Furthermore, the moving coordinates of the hinge point A between the gantry and the tilt cylinder are obtained using the following formula: x1'=\sqrt {\left ( {x1-x2} \right )^{2}+\left ( {y1-y2} \right )^{2}}\times \sin {\left [ {{{{{tan}^{-1}}^{}}^{}\left ( \left | {\frac {x1} {y1}} \right | \right )+\theta}} \right ]} , y1'=\sqrt {\left ( {x1-x2} \right )^{2}+\left ( {y1-y2} \right )^{2}}\times \cos {\left [ {{tan}^{-1}\left ( \left | {\frac {x1} {y1}} \right | \right )+\theta} \right ]} , Among them, (x1, y1) is the original coordinate of the hinge point A between the mast and the tilt cylinder, (x1', y1') is the moving coordinate of the hinge point A between the mast and the tilt cylinder, (x2, y2) is the coordinate of the hinge point B between the forklift body and the tilt cylinder, (0, 0) is the coordinate of the center O of the front axle, and θ is the mast tilt angle.

[0009] Furthermore, the vertical distance from the center O of the front axle to the tilt cylinder is obtained using the following formula: , where L is the vertical distance from the center of the front axle O to the tilt cylinder.

[0010] Furthermore, the method also includes: calibrating different gantry inclination angles and corresponding hydraulic cylinder force data when unloaded, and calculating the gantry self-weight moment under different gantry inclination angles, fitting a relationship curve between the gantry inclination angle and the gantry self-weight moment, and embedding the relationship curve data into a storage module.

[0011] A second aspect of the present application provides a forklift rollover prediction system, which is used for the above-mentioned forklift rollover prediction method, including a control module, a detection module connected to the control module, a storage module and an early warning module, wherein the detection module is used to detect the posture state of the forklift in real time and transmit the detection data to the control module; the storage module is used to store the original data of the forklift; the control module is used to calculate the longitudinal stability coefficient of the forklift based on the data in the storage module and the detection data transmitted by the detection module; when the longitudinal stability coefficient exceeds a set threshold, the control module controls the early warning module to issue an early warning.

[0012] Furthermore, the detection module includes a rotation angle sensor for detecting the tilt angle of the mast and a pressure sensor for detecting the hydraulic oil pressure in the tilt cylinder.

[0013] A third aspect of the present application provides a forklift, comprising a forklift body, a front axle, a rear axle and a mast, wherein a tilt cylinder is connected between the mast and the forklift body, and also comprising the forklift rollover prediction system mentioned above.

[0014] Compared with the prior art, the beneficial effects of this application are: The forklift rollover prediction method, system and forklift provided in the embodiments of the present application are based on the change of the inclination angle of the mast. The method calculates the vertical distance from the center of the front axle to the tilt cylinder, that is, the lever arm of the tilt cylinder force relative to the center of the front axle, in real time through the triangular geometric properties of the mast and the tilt cylinder hinge point, the front axle center and the forklift body and the tilt cylinder hinge point, and calculates the tilt cylinder force based on the hydraulic oil pressure in the tilt cylinder. The rollover moment of the forklift is calculated through the tilt cylinder force and the lever arm of the tilt cylinder force relative to the center of the front axle, and finally the longitudinal stability coefficient of the forklift is calculated in real time.

[0015] This method only needs to obtain the mast inclination angle and the hydraulic oil in the tilt cylinder. Less variable data is required, and the calculation results are reliable and accurate, and can be applied to various operating conditions. When the forklift operation exceeds the longitudinal stability coefficient threshold, an early warning is issued to reduce the risk of forklift tipping and ensure the safety of operating equipment and personnel. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a flow chart of a forklift rollover prediction method of the present application; Figure 2is a flow chart of obtaining the actual tipping moment in the forklift tipping prediction method of the present application; Figure 3 It is a flow chart of the force arm of the tilt cylinder in the forklift tipping prediction method of the present application; Figure 4 It is a schematic diagram of the structure of the forklift of the present application; Figure 5 is a schematic diagram of the moment arm for calculating the force of the tilt cylinder of the present application; Figure 6 is a curve diagram of the gantry inclination angle and the gantry deadweight moment of the present application; Description of reference numerals: 1. Cargo; 2. Mast; 3. Tilt cylinder; 4. Forklift body; 5. Front axle; 6. Rear axle. DETAILED DESCRIPTION

[0017] In order to facilitate the understanding of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0018] refer to Figure 4 As shown, the present application provides a forklift for handling, loading and unloading of goods 1, including a forklift body 4, a front axle 5, a rear axle 6, a cargo fork and a mast 2, the cargo fork is connected to the mast 2 in a sliding manner, the bottom end of the mast 2 is hinged to the forklift body 4, and a tilting cylinder 3 is also connected between the mast 2 and the forklift body 4. By adjusting the extension and contraction amount of the tilting cylinder 3, the angle between the mast 2 and the ground can be changed, thereby adjusting the tilt angle of the cargo fork, so as to facilitate the forklift to operate on uneven ground or to dump goods 1.

[0019] The present application also provides a forklift rollover prediction system, including a control module, a detection module electrically connected to the control module, a storage module and an early warning module. The detection module is used to detect the posture state of the forklift in real time and transmit the detection data to the control module.

[0020] The storage module is used to store the original data of the forklift, wherein the original data includes the longitudinal stability moment of the forklift, the correspondence between the mast inclination angle and the mast deadweight moment, the original coordinates of the hinge point A between the mast 2 and the tilt cylinder 3, the coordinates of the hinge point B between the forklift body 4 and the tilt cylinder 3, the coordinates of the center O of the front axle 5, and the dimensions of the tilt cylinder 3 and the piston rod.

[0021] The control module is used to calculate the longitudinal stability coefficient of the forklift according to the data in the storage module and the detection data transmitted by the detection module; when the longitudinal stability coefficient exceeds the set threshold, the control module controls the warning module to issue a warning.

[0022] In some embodiments, the control module includes a calculation unit, a judgment unit and a control unit. The calculation unit is used to calculate the longitudinal stability coefficient of the forklift based on the original data in the storage module and the detection data transmitted by the detection module, and transmit the calculation result to the judgment unit; the judgment unit is used to determine whether the longitudinal stability coefficient of the forklift exceeds a set threshold. When the longitudinal stability coefficient of the forklift exceeds the set threshold, the judgment unit transmits warning information to the control unit; the control unit is used to control the warning module to issue a warning based on the information transmitted by the judgment unit.

[0023] In some embodiments, the detection module includes a rotation angle sensor for detecting the tilt angle of the mast 2 and a pressure sensor for detecting the hydraulic oil pressure in the tilt cylinder 3 .

[0024] The forklift tipping prediction system of this embodiment requires a small number of sensors, is easy to install, and reduces system cost and complexity. At the same time, the accuracy of longitudinal stability coefficient calculation is improved through real-time monitoring data from a small number of sensors and precise theoretical calculation.

[0025] This application also provides a forklift rollover prediction method, referring to Figure 1 As shown, the following steps are included: Step S100, detecting the posture state of the forklift mast 2 in real time, and obtaining the tilt angle of the mast 2 when the mast 2 tilts; Step S200, obtaining the force of the tilt cylinder 3 connected between the mast 2 and the forklift body 4; Step S300, obtaining the actual tipping moment according to the force of the tilt cylinder 3 and the tilt angle of the mast 2; Step S400, obtaining the self-weight moment of the gantry according to the inclination angle of the gantry 2; Step S500, obtaining a longitudinal stability coefficient according to the actual tipping moment, the mast deadweight moment and the built-in longitudinal stability moment, and issuing an early warning when the longitudinal stability coefficient exceeds a set threshold.

[0026] In some embodiments, reference Figure 2 As shown, the actual tipping moment is obtained according to the force of the tilt cylinder 3 and the tilt angle of the mast 2 in step S300, including: Step 310, obtaining the force of the tilt cylinder 3 according to the hydraulic oil pressure of the tilt cylinder 3, the tilt cylinder 3 and the piston rod ruler; Step 320, obtaining the force arm of the tilt cylinder according to the tilt angle of the gantry 2; Step 330: Obtain the actual tipping moment according to the tilt cylinder force and the lever arm of the tilt cylinder force.

[0027] In some embodiments, reference Figure 3 As shown, the step 320 of obtaining the force arm of the tilt cylinder according to the tilt angle of the gantry 2 includes: Step 321, obtaining the moving coordinates of the hinge point A between the gantry 2 and the tilt cylinder 3 according to the tilt angle of the gantry 2; Step 322, obtain the vertical distance from the front axle center O to the tilt cylinder 3, that is, the force arm of the tilt cylinder force, through the moving coordinates of the hinge point A of the gantry 2 and the tilt cylinder 3, wherein the front axle center is also the rotation center of the gantry.

[0028] In some embodiments, reference Figure 5 As shown, the moving coordinates of the hinge point A between the gantry 2 and the tilt cylinder 3 are obtained using the following formula: x1'=\sqrt {\left ( {x1-x2} \right )^{2}+\left ( {y1-y2} \right )^{2}}\times \sin {\left [ {{{{{tan}^{-1}}^{}}^{}\left ( \left | {\frac {x1} {y1}} \right | \right )+\theta}} \right ]} , y1'=\sqrt {\left ( {x1-x2} \right )^{2}+\left ( {y1-y2} \right )^{2}}\times \cos {\left [ {{tan}^{-1}\left ( \left | {\frac {x1} {y1}} \right | \right )+\theta} \right ]} , Among them, (x1, y1) is the original coordinate of the hinge point A between the mast 2 and the tilt cylinder 3, (x1', y1') is the moving coordinate of the hinge point A between the mast 2 and the tilt cylinder 3, (x2, y2) is the coordinate of the hinge point B between the forklift body 4 and the tilt cylinder 3, (0, 0) is the coordinate of the center O of the front axle, and θ is the mast tilt angle.

[0029] In some embodiments, the vertical distance from the front axle center O to the tilt cylinder 3 is obtained using the following formula: , where L is the vertical distance from the front axle center O to the tilt cylinder 3.

[0030] In some embodiments, reference Figure 6 As shown, in step S400, the gantry self-weight moment is obtained according to the inclination angle of the gantry 2, including: calibrating different gantry inclination angles and corresponding hydraulic cylinder force data when unloaded, and calculating the gantry self-weight moment under different gantry inclination angles, fitting it into a relationship curve between the gantry inclination angle and the gantry self-weight moment, and embedding the relationship curve data into the storage module.

[0031] In some embodiments, the longitudinal stability coefficient is obtained using the following formula: K=(M2-M1) / M0, where M0 is the longitudinal stability moment, M1 is the mast deadweight moment, and M2 is the actual tipping moment; where the longitudinal stability moment is the product of the rear axle 6 load and the forklift wheelbase when unloaded.

[0032] The forklift rollover prediction method of this embodiment is based on the change of the mast inclination angle and the hydraulic oil pressure in the tilt cylinder 3, and finally calculates the longitudinal stability coefficient of the forklift in real time. This method improves the accuracy of the longitudinal stability coefficient calculation through real-time monitoring data of a small number of sensors and precise theoretical calculation. When the forklift operation exceeds the longitudinal stability coefficient threshold, an early warning is issued to reduce the risk of forklift rollover and ensure the safety of operating equipment and personnel.

[0033] A specific embodiment of the forklift rollover prediction method of the present application is described below: During the operation of the forklift, the inclination angle of the gantry 2 is detected in real time by the angle sensor of the gantry 2. When the inclination angle of the gantry 2 changes, the angle sensor transmits the detected gantry inclination angle θ to the control module.

[0034] After the control module receives the gantry tilt angle θ transmitted by the angle sensor, the control module obtains the hydraulic oil pressure of the tilt cylinder 3 through the pressure sensor in the tilt cylinder 3, and then retrieves the size of the tilt cylinder 3 and the piston rod from the storage module, and calculates the tilt cylinder force F through the hydraulic oil pressure of the tilt cylinder 3, the size of the tilt cylinder 3 and the piston rod.

[0035] At the same time, the control module retrieves the original coordinates (x1, y1) of the hinge point A between the mast 2 and the tilt cylinder 3, the coordinates (x2, y2) of the hinge point B between the forklift body 4 and the tilt cylinder 3, and the coordinates (0, 0) of the front axle center O from the storage module, where the front axle center O is the coordinate origin, the vertical direction is the x-axis, and the horizontal direction is the y-axis. Using the triangular geometric properties of the hinge point A between the mast 2 and the tilt cylinder 3, the hinge point B between the forklift body 4 and the tilt cylinder 3, and the front axle center O, the moving coordinates (x1', y1') of the hinge point A between the mast 2 and the tilt cylinder 3 are calculated, where x1'=\sqrt {\left ( {x1-x2} \right )^{2}+\left ( {y1-y2} \right )^{2}}\times \sin {\left [ {{{{{tan}^{-1}}^{}}^{}\left ( \left | {\frac {x1} {y1}} \right | \right )+\theta}} \right ]} , y1'=\sqrt {\left ( {x1-x2} \right )^{2}+\left ( {y1-y2} \right )^{2}}\times \cos {\left [ {{tan}^{-1}\left ( \left | {\frac {x1} {y1}} \right | \right )+\theta} \right ]} .

[0036] The control module calculates the vertical distance L from the front axle center O to the tilt cylinder 3, that is, the force arm of the tilt cylinder force F relative to the front axle center O, based on the moving coordinates (x1', y1') of the hinge point A between the mast 2 and the tilt cylinder 3. .

[0037] The control module calculates the actual tipping moment M2 according to the tilt cylinder force F and the lever arm L of the tilt cylinder force F relative to the front axle center O, where M2=F*L.

[0038] Then, the control module retrieves the correspondence between the mast inclination angle and the mast self-weight moment from the storage module, and obtains the mast self-weight moment M1 according to the mast inclination angle θ. The longitudinal stability moment M0 of the forklift is retrieved from the storage module, where the longitudinal stability moment M0 is the product of the rear axle 6 load and the forklift wheelbase.

[0039] Finally, the control module calculates the longitudinal stability coefficient K according to the longitudinal stability moment M0, the mast self-weight moment M1 and the actual tipping moment M2, where K=(M2-M1) / M0. The control module compares the longitudinal stability coefficient K with the set threshold value. When the longitudinal stability coefficient K exceeds the set threshold value, the control module controls the early warning module to issue an early warning. Preferably, the threshold value set for the longitudinal stability coefficient K in this embodiment is 1.1.

[0040] The above shows and describes the basic principles, main features and advantages of the present application. Those skilled in the art should understand that the present application is not limited by the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present application. Without departing from the spirit and scope of the present application, the present application may have various changes and improvements, which fall within the scope of the present application to be protected. The scope of protection claimed in the present application is defined by the attached claims and their equivalents.

Claims

1. A forklift rollover prediction method, characterized in that: The following steps are involved: Detect the posture status of the forklift mast in real time and obtain the mast's tilt angle when the mast tilts; Obtain the force of the tilt cylinder connected between the mast and the forklift body; The actual tipping moment is obtained according to the force of the tilt cylinder and the tilt angle of the mast; Obtain the self-weight moment of the gantry according to the inclination angle of the gantry; The longitudinal stability coefficient is obtained based on the actual overturning moment, the mast's deadweight moment and the built-in longitudinal stability moment, and an early warning is issued when the longitudinal stability coefficient exceeds the set threshold.

2. The forklift rollover prediction method according to claim 1, characterized in that: The longitudinal stability coefficient is obtained using the following formula: K=(M2-M1) / M0, where K is the longitudinal stability coefficient, M0 is the longitudinal stability moment, M1 is the mast deadweight moment, and M2 is the actual tipping moment; where the longitudinal stability moment is the product of the rear axle load and the forklift wheelbase when unloaded.

3. The forklift rollover prediction method according to claim 1, characterized in that: The actual tipping moment is obtained according to the force of the tilt cylinder and the tilt angle of the mast, including: The tilt cylinder force is obtained according to the hydraulic oil pressure of the tilt cylinder, the tilt cylinder and the piston rod scale; Obtain the force arm of the tilt cylinder according to the tilt angle of the gantry; The actual tipping moment is obtained according to the tilt cylinder force and the lever arm of the tilt cylinder force.

4. The forklift rollover prediction method according to claim 3, characterized in that: The method of obtaining the force arm of the tilt cylinder according to the tilt angle of the gantry comprises: The moving coordinates of the hinge point A between the gantry and the tilt cylinder are obtained through the tilt angle of the gantry. The vertical distance from the front axle center O to the tilt cylinder, that is, the force arm of the tilt cylinder force, is obtained through the moving coordinates of the door frame and the hinge point A of the tilt cylinder.

5. The forklift rollover prediction method according to claim 4, characterized in that: The moving coordinates of the hinge point A between the gantry and the tilt cylinder are obtained using the following formula: ， ， Among them, (x1, y1) is the original coordinate of the hinge point A between the mast and the tilt cylinder, (x1', y1') is the moving coordinate of the hinge point A between the mast and the tilt cylinder, (x2, y2) is the coordinate of the hinge point B between the forklift body and the tilt cylinder, (0, 0) is the coordinate of the center O of the front axle, and θ is the mast tilt angle.

6. The forklift rollover prediction method according to claim 5, characterized in that: Use the following formula to obtain the vertical distance from the front axle center O to the tilt cylinder: , where L is the vertical distance from the center of the front axle O to the tilt cylinder.

7. The forklift rollover prediction method according to claim 2, characterized in that: The method also includes: calibrating different mast inclination angles and corresponding hydraulic cylinder force data when unloaded, and calculating the mast self-weight moment at different mast inclination angles, fitting a relationship curve between the mast inclination angle and the mast self-weight moment, and storing the relationship curve data in a storage module.

8. A forklift rollover prediction system, used to implement the forklift rollover prediction method according to any one of claims 1 to 7, characterized in that: It includes a control module, a detection module connected to the control module, a storage module and an early warning module, wherein the detection module is used to detect the posture state of the forklift in real time and transmit the detection data to the control module; The storage module is used to store the original data of the forklift; the control module is used to calculate the longitudinal stability coefficient of the forklift according to the data in the storage module and the detection data transmitted by the detection module; when the longitudinal stability coefficient exceeds the set threshold, the control module controls the early warning module to issue an early warning.

9. The forklift rollover prediction system according to claim 8, characterized in that: The detection module includes a rotation angle sensor for detecting the tilt angle of the mast and a pressure sensor for detecting the hydraulic oil pressure in the tilt cylinder.

10. A forklift, comprising a forklift body, a front axle, a rear axle and a mast, wherein a tilt cylinder is connected between the mast and the forklift body, characterized in that: It also includes a forklift rollover prediction system as described in any one of claims 8-9.

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