Control method and device for preventing tipping of forklift, forklift and storage medium

Abstract

The invention discloses a control method and device for preventing tipping of a forklift, the forklift and a storage medium, and belongs to the field of engineering machinery. The method comprises the steps that the real-time load forward-tilting moment of the forklift is determined according to the real-time load weight, the lifting height, the portal frame inclination angle and the slope angle; the real-time pallet fork related forward-tilting moment of the forklift is determined according to the predetermined pallet fork related weight, the predetermined driving acceleration, the predetermined lifting acceleration, the predetermined portal inclination angle, the predetermined slope angle and the predetermined lifting height; according to the predetermined portal weight, the driving acceleration, the portal inclination angle, the slope angle and the lifting height, the real-time portal forward-tilting moment of the forklift is determined; according to the pre-determined no-load rear axle weight, the running acceleration and the slope angle, the real-time longitudinal anti-rollover moment of the forklift is determined; and according to the real-time load forward-tilting moment, the real-time pallet fork related forward-tilting moment, the real-time portal frame forward-tilting moment and the real-time longitudinal anti-tilting moment, anti-tilting control is conducted on the forklift. The control precision can be improved.

Description

Technical Field

[0001] This application relates to the field of engineering machinery technology, specifically to a control method, device, forklift, and storage medium for preventing forklifts from tipping over. Background Technology

[0002] Forklifts are key equipment in modern logistics, but they are prone to tipping over, causing serious personal injury and property damage. Among these accidents, longitudinal tipping accidents caused by insufficient longitudinal stability have become a significant safety hazard.

[0003] In existing technologies, sensors are typically used to collect load data and monitor the percentage of the load relative to the total machine weight to determine overall stability and thus achieve forklift anti-tipping control. However, relying solely on load to determine forklift stability in existing technologies can compromise the accuracy of anti-tipping control. Therefore, existing solutions suffer from low accuracy in forklift anti-tipping control. Summary of the Invention

[0004] The purpose of this application is to provide a control method, device, forklift, and storage medium for preventing forklift tipping, in order to solve the problem of low accuracy in the existing forklift tipping control.

[0005] To achieve the above objectives, the first aspect of this application provides a control method for preventing forklift tipping, the control method comprising: Obtain real-time operating parameters of the forklift, including real-time load weight, forklift travel acceleration, fork lifting acceleration, mast tilt angle, slope angle of the ramp where the forklift is located, and fork lifting height. The real-time load tilting torque of the forklift is determined based on the real-time load weight, lifting height, mast tilt angle, and ramp angle. Based on the predetermined fork-related weight, travel acceleration, lifting acceleration, mast tilt angle, ramp angle, and lifting height, determine the real-time fork-related tilting torque of the forklift. The real-time mast tilting moment of the forklift is determined based on the predetermined mast weight, travel acceleration, mast tilt angle, ramp angle, and lifting height. The real-time longitudinal anti-tipping moment of the forklift is determined based on the predetermined unloaded rear axle weight, driving acceleration, and slope angle. Anti-tipping control of the forklift is performed based on real-time load tilting moment, real-time fork-related tilting moment, real-time mast tilting moment, and real-time longitudinal anti-tipping moment.

[0006] In this embodiment, obtaining the real-time load weight includes: selecting a target lifting pressure-load weight relationship corresponding to the lifting height; obtaining the lifting pressure of the forklift's lifting hydraulic system; determining the initial load weight based on the target lifting pressure-load weight relationship; and performing a Kalman filter operation on the initial load weight to obtain the real-time load weight.

[0007] In this embodiment of the application, determining the real-time load forward tilting moment of the forklift based on the real-time load weight, lifting height, mast tilt angle, and ramp angle includes: determining the real-time load force based on the real-time load weight; determining the real-time load forward tilting moment of the forklift based on the real-time load force, lifting height, mast tilt angle, and ramp angle; wherein, determining the real-time load forward tilting moment of the forklift based on the real-time load force, lifting height, mast tilt angle, and ramp angle includes determining the real-time load forward tilting moment according to the following formula (1): M tip =G1[(H+h)sin(α+β)+L c cos(α+β)+Xcosβ](1) Where G1 is the real-time load force, α is the mast tilt angle, β is the ramp angle, H is the lifting height, h is the fork thickness, and L is the horizontal displacement. c M is the standard load center distance of the forklift, X is the front overhang distance of the forklift, and M is the center distance of the forklift. tip This is the real-time load tilting torque.

[0008] In this embodiment, the real-time fork-related tilting moment of the forklift is determined based on predetermined fork-related weight, travel acceleration, lifting acceleration, mast tilt angle, ramp angle, and lifting height. This includes: determining the fork-related static gravity based on the predetermined fork-related weight; determining the first vertical component of lifting acceleration / deceleration based on the fork-related weight, lifting acceleration, mast tilt angle, and ramp angle; determining the first vertical component of longitudinal acceleration / deceleration based on the fork-related weight, mast tilt angle, and travel acceleration; determining the sum of the fork-related static gravity, the first vertical component of lifting acceleration / deceleration, and the first vertical component of longitudinal acceleration / deceleration to obtain the real-time fork-related force; and determining the real-time fork-related tilting moment of the forklift based on the real-time fork-related force, lifting height, mast tilt angle, and ramp angle.

[0009] In this embodiment of the application, the first vertical component of lifting acceleration and deceleration is determined based on the fork-related weight, lifting acceleration, mast tilt angle, and ramp angle, including determining the first vertical component of lifting acceleration and deceleration according to the following formula (2): G2 起升 =M2a1 / cos(α+β)(2) Based on the fork weight, mast tilt angle, and travel acceleration, determine the first longitudinal acceleration / deceleration vertical component, including determining the first longitudinal acceleration / deceleration vertical component according to the following formula (3): G2 纵向 =M2a2tanα(3) Based on the real-time fork-related forces, lifting height, mast tilt angle, and ramp angle, determine the real-time fork-related tilting moment of the forklift, including determining the real-time fork-related tilting moment according to the following formula (4): M f =G2[(H+h)sin(α+β)+d_fcosβ] (4) Among them, G2 起升 M2 is the vertical component of the initial lifting acceleration and deceleration force, a1 is the lifting acceleration, α is the mast tilt angle, β is the ramp angle, and G2 is the vertical component of the initial lifting acceleration and deceleration force. 纵向 Let a2 be the vertical component of the first longitudinal acceleration / deceleration force, G2 be the travel acceleration, G2 be the real-time fork-related force, H be the lifting height, h be the fork thickness, d_f be the horizontal distance from the horizontal component of the fork-related center of gravity to the mast hinge point when the forklift mast is vertical, and M be the vertical component of the fork-related center of gravity. f This refers to the real-time fork tilting torque.

[0010] In this embodiment, the mast includes an outer mast and a non-outer mast. The mast weight includes the total mast weight of the outer mast and the non-outer mast, and the non-outer mast weight of the non-outer mast. Based on the predetermined mast weight, travel acceleration, mast tilt angle, ramp angle, and lifting height, the real-time mast tilting moment of the forklift is determined, including: determining the mast static gravity based on the total mast weight; determining the second longitudinal acceleration / deceleration vertical component based on the total mast weight, travel acceleration, and mast tilt angle; and determining the second lifting acceleration / deceleration vertical component based on the non-outer mast weight, lifting acceleration, mast tilt angle, and ramp angle. The following parameters are used to determine the real-time mast force: When the lifting height is less than a preset lifting height threshold, the sum of the mast static gravity and the second longitudinal acceleration / deceleration vertical component is determined to obtain the real-time mast force. The preset lifting height threshold is the lifting height of the forks when the non-outer mast begins to lift. When the lifting height is greater than or equal to the preset lifting height threshold, the sum of the mast static gravity, the second longitudinal acceleration / deceleration vertical component, and the second lifting acceleration / deceleration vertical component is determined to obtain the real-time mast force. Based on the real-time mast force, mast tilt angle, ramp angle, and lifting height, the real-time mast forward tilting moment of the forklift is determined.

[0011] In this embodiment of the application, the second longitudinal acceleration and deceleration vertical component is determined based on the total gantry weight, driving acceleration, and gantry tilt angle, including determining the second longitudinal acceleration and deceleration vertical component according to the following formula (5): G3 纵向 =M3a2tanα(5) The second vertical component of the lifting acceleration and deceleration force is determined based on the weight of the non-outer gantry, the lifting acceleration, the gantry tilt angle, and the ramp angle, including the determination of the second vertical component of the lifting acceleration and deceleration force according to the following formula (6): G3 起升 =M4a1 / cos(α+β)(6) Based on the real-time mast force, mast tilt angle, ramp angle, and lifting height, determine the forklift's real-time mast tilting moment, including: When the lifting height is less than the preset lifting height threshold, the real-time gantry tilting moment is determined according to the following formula (7): (7) When the lifting height is greater than or equal to the preset lifting height threshold, the real-time gantry tilting moment is determined according to the following formula (8): (8) Among them, G3 纵向 The second longitudinal acceleration and deceleration vertical component, M3 is the total gantry weight, a2 is the travel acceleration, α is the gantry tilt angle, and G3 is the vertical component of the acceleration and deceleration. 起升 M4 represents the vertical component of the second lifting acceleration and deceleration force, a1 represents the lifting acceleration, β represents the ramp angle, G3 represents the real-time gantry force, H represents the lifting height, Hc represents the preset lifting height threshold, h_m represents the vertical distance from the vertical component of the gantry's center of gravity to the gantry hinge point, d_m represents the horizontal distance from the horizontal component of the gantry's center of gravity to the gantry hinge point when the gantry is not vertically lifted, mi represents the weight of the i-th gantry, zi represents the vertical distance from the vertical component of the i-th gantry's center of gravity to the gantry hinge point in the dynamic state, n represents the total number of gantry, M m This is the real-time gantry tilting moment.

[0012] In this embodiment of the application, the real-time longitudinal anti-tipping moment of the forklift is determined based on the predetermined unloaded rear axle weight, driving acceleration, and slope angle, including determining the real-time longitudinal anti-tipping moment according to the following formula (9): M w = W1(g-a2cosβ)Lcosβ(9) Among them, M w The real-time longitudinal anti-tipping moment is given by W1, where W1 is the unloaded rear axle weight, g is the gravitational acceleration, a2 is the driving acceleration, β is the slope angle, and L is the forklift wheelbase.

[0013] In this embodiment, anti-tipping control of the forklift is performed based on the real-time load tilting moment, the real-time fork-related tilting moment, the real-time mast tilting moment, and the real-time longitudinal anti-tipping moment. This includes: determining the sum of the real-time load tilting moment, the real-time fork-related tilting moment, and the real-time mast tilting moment to obtain the total real-time tilting moment; issuing a tilting warning signal when the total real-time tilting moment is greater than a first preset multiple and less than a second preset multiple of the real-time longitudinal anti-tipping moment, wherein both the first and second preset multiples are less than 1, and the first preset multiple is less than the second preset multiple; and locking the forklift or limiting its speed when the total real-time tilting moment is greater than or equal to the second preset multiple of the real-time longitudinal anti-tipping moment.

[0014] In this embodiment of the application, the control method further includes: determining the corresponding current allowable lifting height based on the real-time load weight according to the predetermined correspondence between the load weight and the allowable lifting height of the forks; prohibiting the lifting action of the forklift when the lifting height is greater than or equal to the current allowable lifting height; and not prohibiting the lifting action of the forklift when the lifting height is less than the current allowable lifting height.

[0015] A second aspect of this application provides a control device for preventing forklift tipping, comprising: a memory configured to store instructions; and a processor configured to retrieve instructions from the memory and, when executing the instructions, to implement the control method for preventing forklift tipping as described above.

[0016] A third aspect of this application provides a forklift, including: the control device for preventing the forklift from tipping over as described above.

[0017] A fourth aspect of this application provides a machine-readable storage medium storing instructions for causing a machine to perform the control method for preventing a forklift from tipping over as described above.

[0018] The above technical solution acquires real-time operating parameters of the forklift, including real-time load weight, forklift acceleration, fork lifting acceleration, mast tilt angle, slope angle of the ramp, and fork lifting height. Based on these parameters, the real-time load-related tilting moment, real-time fork-related tilting moment, real-time mast tilting moment, and real-time longitudinal anti-tipping moment can be obtained. Anti-tipping control is then implemented based on these moments. This solution considers not only the impact of load on forklift stability but also the effects of forklift acceleration, fork lifting acceleration, mast tilt angle, slope angle, and fork lifting height on stability. This allows for a more comprehensive analysis of the impact of various dynamic factors on anti-tipping control, improving the accuracy of anti-tipping control and ultimately enhancing forklift safety.

[0019] Other features and advantages of the embodiments of this application will be described in detail in the following detailed description section. Attached Figure Description

[0020] The accompanying drawings are provided to further illustrate the embodiments of this application and form part of the specification. They are used together with the following detailed description to explain the embodiments of this application, but do not constitute a limitation on the embodiments of this application. In the drawings: Figure 1 The illustration shows a schematic flowchart of a control method for preventing forklift tipping according to an embodiment of this application; Figure 2 A schematic diagram of a forklift structure according to an embodiment of this application is shown. Figure 3 This schematically illustrates a control logic diagram of a control method for preventing forklift tipping according to an embodiment of this application; Figure 4 The diagram illustrates a force analysis of a forklift according to an embodiment of this application. Detailed Implementation

[0021] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only for illustration and explanation of the embodiments of this application and are not intended to limit the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0022] It should be noted that the acquisition, transmission, storage, use, and processing of data in the technical solution of this application all comply with relevant laws and regulations. In the embodiments of this application, certain existing industry solutions such as software, components, and models may be mentioned. These should be considered exemplary, intended only to illustrate the feasibility of implementing the technical solution of this application, and do not imply that the applicant has already used or necessarily used such solutions.

[0023] It should be noted that if the embodiments of this application involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0024] Furthermore, if the embodiments of this application involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, features defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed in this application.

[0025] Figure 1 The illustration schematically shows a flow chart of a control method for preventing forklift tipping according to an embodiment of this application. Figure 1 As shown in the figure, this application provides a control method for preventing forklifts from tipping over. Taking the application of this method to a processor as an example, the method may include the following steps.

[0026] Step S102: Obtain the real-time operating parameters of the forklift, including the real-time load weight, the forklift's travel acceleration, the lifting acceleration of the forks, the mast tilt angle, the slope angle of the slope where the forklift is located, and the lifting height of the forks.

[0027] Step S104: Determine the real-time load tilting torque of the forklift based on the real-time load weight, lifting height, mast tilt angle, and ramp angle.

[0028] Step S106: Determine the real-time fork-related tilting torque of the forklift based on the predetermined fork-related weight, travel acceleration, lifting acceleration, mast tilt angle, ramp angle, and lifting height.

[0029] Step S108: Determine the real-time mast tilting moment of the forklift based on the predetermined mast weight, travel acceleration, mast tilt angle, ramp angle, and lifting height.

[0030] Step S110: Determine the real-time longitudinal anti-tipping torque of the forklift based on the predetermined unloaded rear axle weight, driving acceleration, and slope angle.

[0031] Step S112: Based on the real-time load tilting moment, the real-time fork-related tilting moment, the real-time mast tilting moment, and the real-time longitudinal anti-tipping moment, perform anti-tipping control on the forklift.

[0032] Real-time operating parameters refer to the forklift's operating parameters at the current moment. This can be understood as the forklift being either stationary or in motion. Specific parameters include real-time load weight, forklift acceleration, fork lifting acceleration, mast tilt angle, slope angle of the ramp, and fork lifting height. Real-time load weight is the forklift's load at the current moment. Real-time load tilting moment is the moment generated by the weight of the real-time load on the forklift, causing the forklift to tilt forward around the front wheel pivot. Real-time fork-related tilting moment is the moment generated by the weight of the forklift's forklift and fork carriage relative to the front wheel pivot, causing the forklift to tilt forward. Real-time mast tilting moment is the moment generated by the weight of the forklift's mast relative to the front wheel pivot, causing the forklift to tilt forward around the front wheel pivot. Real-time longitudinal anti-tipping moment is the stabilizing moment generated by the forklift's rear axle at the current moment, used to measure the forklift's ability to resist forward tipping. Understandably, real-time load weight can be obtained by detecting the current lifting pressure of the lifting hydraulic system, based on the correspondence between the lifting pressure and load weight of the lifting hydraulic system. The forklift's travel acceleration and fork lifting acceleration can be obtained through corresponding acceleration detection devices (such as acceleration sensors), or calculated from travel speed and lifting speed. The mast tilt angle and the slope angle of the ramp where the forklift is located can be detected through corresponding angle detection devices (such as angle sensors). The fork lifting height can be detected through corresponding height detection devices (such as height sensors). Fork-related weight is the weight of the forklift's fork-related structural components (including forks and fork carriages, etc.), which can be predetermined through the forklift's design parameters. Mast weight is the weight of the forklift's mast, which can be predetermined through the forklift's design parameters. Unloaded rear axle weight is the weight of the forklift's rear axle when the forklift is unloaded, which can be predetermined through the forklift's design parameters.

[0033] Specifically, the processor can acquire real-time operating parameters of the forklift, including real-time load weight, forklift travel acceleration, fork lifting acceleration, mast tilt angle, ramp angle, and fork lifting height. Based on the real-time load weight, lifting height, mast tilt angle, and ramp angle, it determines the real-time load-related tilting moment of the forklift. Then, based on predetermined fork-related weight, travel acceleration, lifting acceleration, mast tilt angle, ramp angle, and lifting height, it determines the real-time fork-related tilting moment. Similarly, based on predetermined mast weight, travel acceleration, mast tilt angle, ramp angle, and lifting height, it determines the real-time mast tilting moment. Furthermore, based on predetermined unloaded rear axle weight, travel acceleration, and ramp angle, it determines the real-time longitudinal anti-tipping moment of the forklift. Anti-tipping control of the forklift is implemented based on real-time load-related tilting moment, real-time fork-related tilting moment, real-time mast tilting moment, and real-time longitudinal anti-tipping moment. For example, the values ​​of these three parameters can be compared with the real-time longitudinal anti-tipping moment to determine the forklift's tilting probability. Based on this probability, different levels of anti-tipping control strategies can be applied to achieve effective anti-tipping control of the forklift.

[0034] The aforementioned control method for forklift anti-tipping acquires real-time operating parameters of the forklift, including real-time load weight, forklift acceleration, fork lifting acceleration, mast tilt angle, slope angle of the ramp, and fork lifting height. Based on these parameters, the real-time load-related tilting moment, real-time fork-related tilting moment, real-time mast tilting moment, and real-time longitudinal anti-tipping moment can be obtained. Anti-tipping control is then applied based on these moments. This technical solution considers not only the impact of load on forklift stability but also the effects of forklift acceleration, fork lifting acceleration, mast tilt angle, slope angle, and fork lifting height on stability. This allows for a more comprehensive analysis of the impact of various dynamic factors on anti-tipping control, improving the accuracy of anti-tipping control and ultimately enhancing forklift safety.

[0035] In one embodiment, obtaining the real-time load weight includes: selecting a target lifting pressure-load weight relationship corresponding to the lifting height; obtaining the lifting pressure of the forklift's lifting hydraulic system; determining the initial load weight based on the target lifting pressure-load weight relationship; and performing a Kalman filter operation on the initial load weight to obtain the real-time load weight.

[0036] It is understandable that there is a correspondence between the lifting height of the forks and the lifting pressure-load weight relationship. For example, different lifting height ranges can be defined based on the lifting height, and different lifting height ranges correspond to different lifting pressure-load weight relationships. The correspondence between lifting height and lifting pressure-load weight can be predetermined and stored, as can the lifting pressure-load weight relationships corresponding to different lifting heights. The target lifting pressure-load weight relationship is the lifting pressure-load weight relationship corresponding to the lifting height of the forks in the real-time operating parameters. The initial load weight is the load weight initially determined based on the lifting pressure of the lifting hydraulic system. Understandably, lifting pressure is usually detected by a pressure sensor. However, in the actual operation of a forklift, the data detected by the sensor is often very unstable and affected by factors such as forklift vibration, cargo swaying, and environmental interference. These measurements are full of "noise". In order to extract a stable and accurate actual weight, this application embodiment introduces Kalman filtering. By weighted fusion of measurement data and prediction data, the influence of measurement noise is minimized, the system state is continuously predicted and corrected in combination with sensor data, thereby obtaining the best state estimate of the system.

[0037] Specifically, the processor can select the target lifting pressure-load weight relationship corresponding to the lifting height, thereby obtaining the lifting pressure of the forklift's lifting hydraulic system. Based on the target lifting pressure-load weight relationship, it can determine the initial load weight according to the lifting pressure, and then perform Kalman filtering on the initial load weight to obtain the corrected and optimized real-time load weight.

[0038] In this embodiment, by determining the target lifting pressure-load weight relationship corresponding to the current lifting height, and then determining the preliminary load weight based on the lifting pressure of the lifting hydraulic system and the target lifting pressure-load weight relationship, and performing Kalman filtering on the preliminary load weight, a more accurate optimized real-time load weight can be obtained, improving the accuracy of the real-time load weight parameters, which in turn helps to improve the accuracy of subsequent forklift anti-tipping control.

[0039] In one embodiment, determining the real-time load tilting moment of the forklift based on the real-time load weight, lifting height, mast tilt angle, and ramp angle includes: determining the real-time load force based on the real-time load weight; determining the real-time load tilting moment of the forklift based on the real-time load force, lifting height, mast tilt angle, and ramp angle; wherein, determining the real-time load tilting moment of the forklift based on the real-time load force, lifting height, mast tilt angle, and ramp angle includes determining the real-time load tilting moment according to the following formula (1): M tip =G1[(H+h)sin(α+β)+L ccos(α+β)+Xcosβ](1) Where G1 is the real-time load force, α is the mast tilt angle, β is the ramp angle, H is the lifting height, h is the fork thickness, and L is the horizontal displacement. c M is the standard load center distance of the forklift, X is the front overhang distance of the forklift, and M is the center distance of the forklift. tip This is the real-time load tilting torque.

[0040] It can be understood that the real-time load force is the gravity corresponding to the real-time load weight, specifically the product of the real-time load weight and the gravitational acceleration. From formula (1), it can be seen that the calculation process of the lever arm corresponding to the real-time load force considers factors such as the mast tilt angle, ramp angle, and lifting height. Understandably, the real-time load force itself also considers factors such as lifting acceleration and travel acceleration. Fork thickness, standard load center distance, and front overhang are all design parameters of the forklift itself, which can be obtained in advance. The standard load center distance is the standard horizontal distance from the load center to the front wall of the vertical section of the fork. The front overhang is the horizontal distance from the center of the front wheel to the front wall of the vertical section of the fork.

[0041] Specifically, the processor can determine the real-time load force based on the real-time load weight, and based on the above formula, determine the forklift's real-time load tilting moment according to the real-time load force, lifting height, mast tilt angle, and ramp angle. This process considers the influence of multiple factors on the real-time load tilting moment, improving its accuracy and contributing to enhanced precision in subsequent forklift anti-tipping control.

[0042] In one embodiment, determining the real-time fork-related tilting moment of the forklift based on predetermined fork-related weight, travel acceleration, lifting acceleration, mast tilt angle, ramp angle, and lifting height includes: determining the fork-related static gravity based on the predetermined fork-related weight; determining the first vertical component of lifting acceleration / deceleration based on the fork-related weight, lifting acceleration, mast tilt angle, and ramp angle; determining the first vertical component of longitudinal acceleration / deceleration based on the fork-related weight, mast tilt angle, and travel acceleration; determining the sum of the fork-related static gravity, the first vertical component of lifting acceleration / deceleration, and the first vertical component of longitudinal acceleration / deceleration to obtain the real-time fork-related force; and determining the real-time fork-related tilting moment of the forklift based on the real-time fork-related force, lifting height, mast tilt angle, and ramp angle.

[0043] It can be understood that the static gravity related to the forks is the gravity corresponding to the weight of the forks, specifically the product of the weight of the forks and the acceleration due to gravity. The first vertical component of the lifting acceleration / deceleration force is the vertical force exerted on the fork-related structural components during the lifting motion of the forklift (including lifting acceleration / deceleration). The first vertical component of the longitudinal acceleration / deceleration force is the vertical force exerted on the fork-related structural components during the longitudinal motion of the forklift (including longitudinal acceleration / deceleration). The real-time fork-related force is the sum of the static gravity related to the forks, the first vertical component of the lifting acceleration / deceleration force, and the first vertical component of the longitudinal acceleration / deceleration force at the current moment.

[0044] Specifically, the processor can determine the static gravity related to the forks based on the predetermined fork-related weight, and determine the first vertical component of lifting acceleration and deceleration based on the fork-related weight, lifting acceleration, mast tilt angle, and ramp angle. Then, based on the fork-related weight, mast tilt angle, and travel acceleration, it can determine the first vertical component of longitudinal acceleration and deceleration, thereby determining the sum of the static gravity related to the forks, the first vertical component of lifting acceleration and deceleration, and the first vertical component of longitudinal acceleration and deceleration to obtain the real-time fork-related force. Finally, based on the real-time fork-related force, lifting height, mast tilt angle, and ramp angle, it can determine the real-time fork-related tilting moment of the forklift.

[0045] In this embodiment, in addition to considering the influence of the static gravity related to the forks on the real-time fork-related tilting moment, the influence of the first lifting acceleration and deceleration vertical component and the first longitudinal acceleration and deceleration vertical component on the real-time fork-related tilting moment is also considered, which improves the accuracy of the real-time fork-related tilting moment and helps to improve the accuracy of subsequent forklift anti-tipping control.

[0046] In one embodiment, the first vertical component of the lifting acceleration / deceleration force is determined based on the fork-related weight, lifting acceleration, mast tilt angle, and ramp angle, including determining the first vertical component of the lifting acceleration / deceleration force according to the following formula (2): G2 起升 =M2a1 / cos(α+β)(2) Based on the fork weight, mast tilt angle, and travel acceleration, determine the first longitudinal acceleration / deceleration vertical component, including determining the first longitudinal acceleration / deceleration vertical component according to the following formula (3): G2 纵向 =M2a2tanα(3) Based on the real-time fork-related forces, lifting height, mast tilt angle, and ramp angle, determine the real-time fork-related tilting moment of the forklift, including determining the real-time fork-related tilting moment according to the following formula (4): M f =G2[(H+h)sin(α+β)+d_fcosβ] (4) Among them, G2 起升M2 is the vertical component of the initial lifting acceleration and deceleration force, a1 is the lifting acceleration, α is the mast tilt angle, β is the ramp angle, and G2 is the vertical component of the initial lifting acceleration and deceleration force. 纵向 Let a2 be the vertical component of the first longitudinal acceleration / deceleration force, G2 be the travel acceleration, G2 be the real-time fork-related force, H be the lifting height, h be the fork thickness, d_f be the horizontal distance from the horizontal component of the fork-related center of gravity to the mast hinge point when the forklift mast is vertical, and M be the vertical component of the fork-related center of gravity. f This refers to the real-time fork tilting torque.

[0047] Understandably, when the fork thickness and the mast of the forklift are vertical, the horizontal component of the fork-related center of gravity and the horizontal distance from the mast hinge point are design parameters of the forklift itself and can be obtained in advance.

[0048] In this embodiment, the first lifting acceleration and deceleration vertical component, the first longitudinal acceleration and deceleration vertical component, and the real-time fork-related tilting torque are determined by the above specific formula, which further improves the accuracy of the real-time load tilting torque and helps to improve the accuracy of subsequent forklift anti-tipping control.

[0049] In one embodiment, the mast includes an outer mast and a non-outer mast, and the mast weight includes the total mast weight of the outer and non-outer masts, and the non-outer mast weight of the non-outer mast. The real-time mast tilting moment of the forklift is determined based on the predetermined mast weight, travel acceleration, mast tilt angle, ramp angle, and lifting height, including: determining the mast static gravity based on the total mast weight; determining the second longitudinal acceleration / deceleration vertical component based on the total mast weight, travel acceleration, and mast tilt angle; and determining the second lifting acceleration / deceleration vertical component based on the non-outer mast weight, lifting acceleration, mast tilt angle, and ramp angle. The following parameters are used to determine the real-time mast force: When the lifting height is less than a preset lifting height threshold, the sum of the mast static gravity and the second longitudinal acceleration / deceleration vertical component is determined to obtain the real-time mast force. The preset lifting height threshold is the lifting height of the forks when the non-outer mast begins to lift. When the lifting height is greater than or equal to the preset lifting height threshold, the sum of the mast static gravity, the second longitudinal acceleration / deceleration vertical component, and the second lifting acceleration / deceleration vertical component is determined to obtain the real-time mast force. Based on the real-time mast force, mast tilt angle, ramp angle, and lifting height, the real-time mast forward tilting moment of the forklift is determined.

[0050] It can be understood that "non-outer mast" refers to the mast other than the outer mast, such as the middle mast, outer mast, etc. The total mast weight is the combined weight of the outer and non-outer masts. The non-outer mast weight is the weight of the non-outer masts. The mast weight includes both the total mast weight and the non-outer mast weight; both are design parameters of the forklift itself and can be obtained in advance. The mast static gravity is the gravity corresponding to the total mast weight, specifically the product of the total mast weight and gravitational acceleration. The second longitudinal acceleration / deceleration vertical component is the vertical force acting on the mast during longitudinal movement (including longitudinal acceleration / deceleration). The second lifting acceleration / deceleration vertical component is the vertical force acting on the mast during lifting movement (including lifting acceleration / deceleration). The preset lifting height threshold is a predetermined lifting height value, corresponding to the lifting height of the forks when the non-outer mast begins to lift; this parameter is a design parameter of the forklift itself and can be obtained in advance. Understandably, when the lifting height of the forks is less than the preset lifting height threshold, the real-time mast force is the sum of the static gravity of the mast and the vertical component of the second longitudinal acceleration and deceleration at the current moment; when the lifting height of the forks is greater than or equal to the preset lifting height threshold, the real-time mast force is the sum of the static gravity of the mast, the vertical component of the second longitudinal acceleration and deceleration, and the vertical component of the second lifting acceleration and deceleration at the current moment.

[0051] Specifically, the processor can determine the mast static gravity based on the total mast weight, and then determine the second longitudinal acceleration / deceleration vertical component based on the total mast weight, travel acceleration, and mast tilt angle. It also determines the second lifting acceleration / deceleration vertical component based on the non-outer mast weight, lifting acceleration, mast tilt angle, and ramp angle. When determining the real-time mast force, the processor can compare the current fork lifting height with a preset lifting height threshold. If the lifting height is less than the preset threshold, the processor determines the sum of the mast static gravity and the second longitudinal acceleration / deceleration vertical component to obtain the real-time mast force. If the lifting height is greater than or equal to the preset lifting height threshold, the processor determines the sum of the mast static gravity, the second longitudinal acceleration / deceleration vertical component, and the second lifting acceleration / deceleration vertical component to obtain the real-time mast force. Therefore, the processor can determine the forklift's real-time mast tilting moment based on the real-time mast force, mast tilt angle, ramp angle, and lifting height.

[0052] In this embodiment, in addition to considering the influence of the static gravity of the mast on the real-time mast tilting moment, the lifting height of the forks is also used to determine whether the non-outer mast is lifted. Based on the two cases of the non-outer mast not being lifted and the non-outer mast being lifted, the influence of the second longitudinal acceleration and deceleration vertical component and / or the second lifting acceleration and deceleration vertical component on the real-time mast tilting moment is considered, which improves the accuracy of the real-time mast tilting moment and helps to improve the accuracy of subsequent forklift anti-tipping control.

[0053] In one embodiment, the second longitudinal acceleration / deceleration vertical component is determined based on the total gantry weight, travel acceleration, and gantry tilt angle, including determining the second longitudinal acceleration / deceleration vertical component according to the following formula (5): G3 纵向 =M3a2tanα(5) The second vertical component of the lifting acceleration and deceleration force is determined based on the weight of the non-outer gantry, the lifting acceleration, the gantry tilt angle, and the ramp angle, including the determination of the second vertical component of the lifting acceleration and deceleration force according to the following formula (6): G3 起升 =M4a1 / cos(α+β)(6) Based on the real-time mast force, mast tilt angle, ramp angle, and lifting height, determine the forklift's real-time mast tilting moment, including: When the lifting height is less than the preset lifting height threshold, the real-time gantry tilting moment is determined according to the following formula (7): (7) When the lifting height is greater than or equal to the preset lifting height threshold, the real-time gantry tilting moment is determined according to the following formula (8): (8) Among them, G3 纵向 The second longitudinal acceleration and deceleration vertical component, M3 is the total gantry weight, a2 is the travel acceleration, α is the gantry tilt angle, and G3 is the vertical component of the acceleration and deceleration. 起升 M4 represents the vertical component of the second lifting acceleration and deceleration force, a1 represents the lifting acceleration, β represents the ramp angle, G3 represents the real-time gantry force, H represents the lifting height, Hc represents the preset lifting height threshold, h_m represents the vertical distance from the vertical component of the gantry's center of gravity to the gantry hinge point, d_m represents the horizontal distance from the horizontal component of the gantry's center of gravity to the gantry hinge point when the gantry is not vertically lifted, mi represents the weight of the i-th gantry, zi represents the vertical distance from the vertical component of the i-th gantry's center of gravity to the gantry hinge point in the dynamic state, n represents the total number of gantry, M m This is the real-time gantry tilting moment.

[0054] Understandably, the vertical distance from the vertical component of the mast's center of gravity to the mast hinge point, the horizontal distance from the horizontal component of the mast's center of gravity to the mast hinge point when the mast is not vertically raised, the weight of the i-th mast, the vertical distance from the vertical component of the i-th mast's center of gravity to the mast hinge point in a dynamic state, and the total number of masts are all design parameters of the forklift itself, which can be obtained in advance.

[0055] In this embodiment, the second longitudinal acceleration / deceleration vertical component, the second lifting acceleration / deceleration vertical component, and the real-time mast tilting moment are determined by the above specific formulas, which further improves the accuracy of the real-time mast tilting moment and helps to improve the precision of subsequent forklift anti-tipping control.

[0056] In one embodiment, the real-time longitudinal anti-tipping moment of the forklift is determined based on a predetermined unloaded rear axle weight, driving acceleration, and ramp angle, including determining the real-time longitudinal anti-tipping moment according to the following formula (9): M w = W1(g-a2cosβ)Lcosβ(9) Among them, M w For real-time longitudinal anti-tipping moment, W1 is the unloaded rear axle weight, g is the acceleration due to gravity, a2 is the driving acceleration, β is the slope angle, and L is the forklift wheelbase. Understandably, the wheelbase is the horizontal distance between the center lines of the front and rear axles, a design parameter of the forklift itself, which can be obtained in advance.

[0057] In this embodiment, the real-time longitudinal anti-tipping moment is determined by the above-mentioned specific formula, taking into account the influence of driving acceleration and slope angle on the real-time longitudinal anti-tipping moment, which further improves the accuracy of the real-time longitudinal anti-tipping moment and helps to improve the precision of subsequent forklift anti-tipping control.

[0058] In one embodiment, anti-tipping control of the forklift is performed based on real-time load tilting moment, real-time fork-related tilting moment, real-time mast tilting moment, and real-time longitudinal anti-tipping moment, including: determining the sum of the real-time load tilting moment, real-time fork-related tilting moment, and real-time mast tilting moment to obtain the total real-time tilting moment; issuing a tilting warning signal when the total real-time tilting moment is greater than a first preset multiple and less than a second preset multiple of the real-time longitudinal anti-tipping moment, wherein both the first and second preset multiples are less than 1, and the first preset multiple is less than the second preset multiple; locking the forklift or limiting the speed of the forklift when the total real-time tilting moment is greater than or equal to the second preset multiple of the real-time longitudinal anti-tipping moment.

[0059] It can be understood that the total real-time tilting moment is the sum of the real-time load tilting moment, the real-time fork-related tilting moment, and the real-time mast tilting moment. Both the first preset multiple and the second preset multiple are pre-set multiples, both less than 1, and the first preset multiple is less than the second preset multiple. For example, the value range of the first preset multiple can be 0.75 to 0.85, and the value range of the second preset multiple can be 0.85 to 0.9.

[0060] Specifically, the processor can determine the sum of the real-time load tilting moment, the real-time fork-related tilting moment, and the real-time mast tilting moment to obtain the total real-time tilting moment. It then compares the total real-time tilting moment with the real-time longitudinal anti-tipping moment. When the total real-time tilting moment is greater than a first preset multiple of the real-time longitudinal anti-tipping moment but less than a second preset multiple, the processor can issue a tilting warning signal for a level one warning, such as a flashing icon and a single beep. Alternatively, it can choose not to impose any action restrictions. When the total real-time tilting moment is greater than or equal to the second preset multiple of the real-time longitudinal anti-tipping moment, the processor can lock the forklift or limit its speed, such as stopping it, prohibiting mast lifting and tilting, and allowing it to lower, until the tilting risk is eliminated and the corresponding functions are restored. Additionally, it can issue a severe tilting warning signal, such as a red full-screen warning and a continuous alarm sound.

[0061] In this embodiment, by comparing the real-time load tilting moment, the real-time fork-related tilting moment, the real-time mast tilting moment, and the real-time longitudinal anti-tipping moment, and by performing first-level and second-level warnings based on the comparison results, longitudinal anti-tipping control of different severity levels can be achieved, thereby improving the accuracy of forklift longitudinal anti-tipping control.

[0062] In this embodiment of the application, the control method further includes: determining the corresponding current allowable lifting height based on the real-time load weight according to the predetermined correspondence between the load weight and the allowable lifting height of the forks; prohibiting the lifting action of the forklift when the lifting height is greater than or equal to the current allowable lifting height; and not prohibiting the lifting action of the forklift when the lifting height is less than the current allowable lifting height.

[0063] It is understandable that for each forklift, there is a one-to-one correspondence between the forklift's load capacity and the allowable lifting height of the forks; that is, different load capacities have corresponding maximum lifting height values, and this correspondence can be predetermined and stored. The current allowable lifting height is the allowable lifting height corresponding to the real-time load weight.

[0064] Specifically, the processor can determine the corresponding current allowable lifting height based on a pre-determined correspondence between load weight and the allowable lifting height of the forks, and compare the current lifting height with the current allowable lifting height. If the lifting height is greater than or equal to the current allowable lifting height, the forklift's lifting action is prohibited, i.e., the forklift is prohibited from continuing to lift; if the lifting height is less than the current allowable lifting height, the forklift's lifting action is not prohibited, i.e., the forklift's lifting action is not restricted. Understandably, the control logic in this embodiment does not contradict the anti-tipping control logic described above, and can achieve dual determination of dynamic torque and height-load relationship, providing safety redundancy.

[0065] In one specific embodiment, a control method for preventing forklift tipping is provided.

[0066] This invention's forklift safety load-bearing system monitors three dimensions: load, mast height, and mast / body angle. Mast height measurement uses a long-angle sensor, providing linear height data. The mast angle is also monitored by a long-angle sensor, while the body angle uses a single-axis dynamic tilt sensor. This dynamic tilt sensor utilizes the combined action of a gyroscope and an accelerometer; the gyroscope performs dynamic measurements, while the accelerometer performs static measurements, complementing each other. There are three main methods for load measurement: fork strain gauge, chain tension, and hydraulic. The first two offer higher accuracy but require some modification to the forklift structure. The hydraulic method is simple in principle, easy to implement, and has no impact on the forklift mechanism, but its accuracy is generally lower. Considering that the weighing system in this invention is not used for metrology, for economic and practical purposes, the forklift load measurement uses a hydraulic weighing method. This only requires replacing the vehicle's original three-way speed limit valve (front dual cylinder) with a four-way valve connected to a pressure sensor. Common types of sensors include voltage type, current type, and CAN type. To avoid electromagnetic and power supply interference and to verify the heartbeat of each detection module, CAN type sensors are selected. If the accuracy of the initial data needs to be improved, redundant type sensors can even be selected.

[0067] This method first pre-programs the forklift model, load curve (i.e., the relationship between load and allowable lifting height), and related parameters into the operating system (instrument panel). These parameters mainly include: standard load center distance Lc, front overhang X, wheelbase L, and mast unloaded rear axle load W1. During vehicle debugging and calibration, the forklift model is manually selected, thus determining the relevant parameters. This is done according to the structural parameter diagram (…). Figure 2 ) and control logic diagram ( Figure 3 The system calculates the dynamic real-time load tilting moment Mtip, mast tilting moment Mm, and fork and fork carriage tilting moment Mf. The sum of these three moments is compared with the moment Mw of the static rear axle load W1. When Mtip + Mf + Mm ≥ 0.8Mw, a first-level warning is issued; when Mtip + Mf + Mm ≥ 0.9Mw, a second-level alarm is issued, the vehicle is stopped, mast lifting and tilting are prohibited, but lowering is allowed, until the alarm is cleared and the function is restored.

[0068] The three types of data collected include: lifting height H, which is linear data and requires no extraction or processing; simply calibrate the zero point on the instrument when the forks are at their lowest position. This invention focuses on the effective extraction of load and angle data, using the same method. Taking weighing as an example, to improve weighing accuracy and eliminate interference from factors such as friction, a test calibration method is used to perform linear regression fitting on the lifting pressure of the lifting hydraulic system and the weight of the cargo, obtaining relatively accurate data. Then, the controller performs Kalman filtering on the measured data to obtain reliable data.

[0069] During the test, when the gantry is raised to the point where the secondary gantry begins to move, the pressure value increases significantly. This is because the weight of the inner and middle gantry, lifting cylinders, etc., causes the pressure value to increase. Therefore, multi-segment regression fitting was performed at intervals of H=1.62 meters, with the height at which the secondary gantry begins to move. The first segment calibration (see Table 1): The lifting pressure of the lifting hydraulic system under the conditions of no load, 500kg, 1000kg, 2000kg, and 2500kg standard weights (load center distance 500mm) were recorded sequentially under the conditions of the primary gantry. The second segment calibration (see Table 2): The lifting pressure of the lifting hydraulic system under the conditions of no load, 500kg, 1000kg, 2000kg, and 2500kg standard weights (load center distance 500mm) were recorded sequentially under the conditions of the secondary gantry.

[0070] Table 1 Forklift weighing test data (Level 1 mast, lifting height H < 1.62 meters)

[0071] Table 2 Forklift Weighing Test Data (Secondary Mast, Lifting Height H≥1.62 meters)

[0072] Based on the data in Tables 1 and 2, linear fitting was performed to obtain the fitting curves of lifting pressure versus load for different lifting heights. Finally, the relationship between lifting pressure P and load M can be expressed as: M=0.0095P2+25.137P-326.02 (H<1.62) M=0.0092P2+25.003P-766.61 (H≥1.62) According to the fitting formula, the error at all the above calibration points does not exceed 2%. To make the test more generalizable, the weighing system was tested at other non-calibration points. The test results show that the weighing error of the weighing system is ≤3%; this result indicates that the weighing system has high accuracy.

[0073] Weight data measured by load cells on forklifts is often highly unstable, influenced by factors such as forklift vibration, cargo movement, and environmental interference. These measurements are filled with "noise." To extract stable and accurate actual weight, Kalman filtering is a perfect choice. By weighted fusion of measured and predicted data, the impact of measurement noise is minimized. The system state is continuously predicted and corrected using sensor data, thus obtaining the optimal state estimate of the system. In standard Kalman filtering, the state prediction and update process can be summarized by the following equation.

[0074] State prediction: Xk|k-1 =F k X k-1|k-1 +B k U k In the formula: X k|k-1 For the predicted state; F K X is the state transition matrix; k-1|k-1 The state estimate for the previous time step k-1; B k For control input matrix; U k To control the input.

[0075] Covariance prediction: P k|k-1 =F k P k-1|k-1 F T^k +Q k In the formula: P k|k-1 Let P be the covariance matrix of the prediction, representing the uncertainty of the predicted state; k-1|k-1 Let Q be the optimal state covariance matrix at time k-1; k Let be the process noise covariance matrix, representing the uncertainty in the state transition process.

[0076] Status Update: X k|k = X k|k-1 +K k (Z k -H k X k|k-1 ) In the formula: X k|k X represents the optimal state estimate at time k; k|k-1 This is the optimal state estimate for the previous time step k-1; K k Z is the Kalman gain; k H represents the observation value at time k; k This is the observation matrix.

[0077] Kalman gain calculation: K k =P k|k-1 H T^k / (H k P k|k-1 H T^k +R k ) In the formula: H T^k H represents the observation matrix k transpose of; R k To observe the noise covariance.

[0078] For example: Weighing a 500kg standard weight in a two-stage gantry configuration, a set of observations is obtained every 100ms, resulting in 10 observations per second: 491.5, 493.3, 495.7, 494.4, 496.2, 497.3, 495.7, 494.2, 498.2, and 497.1. Now, simulate Kalman filtering.

[0079] System Model: State vector: X k Weight estimation for the controller at time k; Observation vector: Z k This is the measurement value of the sensor at time k (this value has been fitted by regression). State transition matrix: F K =1 (If the load remains constant during the weighing process, it is considered that the weight is constant). Observation matrix: H k =1 (Ideally, the observed value directly corresponds to the weight) Process noise covariance matrix: Q k =0.1, which is a key "tuning" parameter in Kalman filtering. For weighing, it is usually a very small value, generally ranging from 0.001 to 0.1. Observation noise covariance matrix: R k =10, which is another key “tuning” parameter in Kalman filtering.

[0080] initialization Initial weight estimate: X 0|0 =0kg Initial covariance matrix: P 0|0 =1000 (represents the degree of uncertainty about the initial state; the larger the value, the more uncertain the initial guess. A larger value is usually a safe starting point.) Prediction Steps Predicted weight: X k|k-1 =F k X k-1|k-1 =X k-1|k-1 Predicted covariance: P k|k-1 =F k P k-1|k-1 F T^k +Q k =P k-1|k-1 +0.1 Update steps Calculate the Kalman gain: K k =P k|k-1 / (P k|k-1 +R k ) Updated weight estimate: X k|k=X k|k-1 +K k (Z k -X k|k-1 ) Update covariance matrix: P k|k =(1-K k )P k|k-1 Specific calculations (assuming three time steps) Time step 1 Observed value: Z1 = 491.5 kg Predicted weight: X 1|0 =X 0|0 =0kg Predicted covariance: P 1|0 =P 0|0 +0.1 = 1000.1 Kalman gain: K1=P 1|0 / (P 1|0 +10)≈0.99 Updated weight estimate: X 1|1 =X 1|0 +K1(Z1-X 1|0 = 0 + 0.99 * (491.5 - 0) = 486.59 Update covariance matrix: P 1|1 =(1-K1)P 1|0 = (1 - 0.99) * 1000.1 = 10.001 Time step 2 Observed value: Z2 = 493.3 kg Predicted weight: X 2|1 =X 1|1 =486.59kg Predicted covariance: P 2|1 =P 1|1 +0.1 = 10.101 Kalman gain: K2=P 2|1 / (P 2|1 +10)≈0.503 Updated weight estimate: X 2|2 =X 2|1 +K2(Z2-X 2|1 = 486.59 + 0.503 * (493.3 - 486.59) = 489.97 Update covariance matrix: P 2|2 =(1-K2)P 2|1 = (1 - 0.503) * 10.101 = 5.02 Time step 3 Observed value: Z3 = 495.7 kg Predicted weight: X 3|2 =X 2|2 =489.97kg Predicted covariance: P 3|2 =P 2|2 +0.1=5.12 Kalman gain: K3=P 3|2 / (P 3|2 +10)≈0.339 Updated weight estimate: X 3|3 =X 3|2 +K3(Z3-X 3|2 = 489.97 + 0.339 * (495.7 - 489.97) = 491.91 Update covariance matrix: P 3|3 =(1-K3)P 3|2 = (1 - 0.339) * 5.12 = 3.384 ...After 10 time steps, or 1 second, the final weight estimate is 495.11 kg, with an accuracy of 0.98%. It can be seen that as the amount of observation data increases, the estimated value will gradually converge to the true value.

[0081] To prevent longitudinal tipping, the longitudinal moments theoretically need to be balanced. Therefore, this invention considers the real-time changes in the longitudinal load tilting moment Mtip, mast tilting moment Mm, and fork and fork carriage tilting moment Mf, which simplifies the longitudinal force analysis of the forklift. See details... Figure 4 .

[0082] When performing torque analysis, we can consider the rear axle weight, load, forks, and fork carriage when the mast is vertical and unloaded as separate entities. Their center of gravity position does not change with spatial variation. However, since the mast has multiple mast levels, the center of gravity changes as the mast is lifted. Therefore, the mast part needs to be analyzed in combination with the center of gravity.

[0083] Figure 4 In the formula, G0 is the rear axle gravity when unloaded and the mast is vertical; G1 is the real-time load force, including the static self-weight of the load, its corresponding vertical component during lifting acceleration, and its vertical component during longitudinal acceleration and deceleration; G2 is the real-time force of the forks and fork carriage, including the static self-weight, its corresponding vertical component during lifting acceleration, and its vertical component during longitudinal acceleration and deceleration; G3 is the real-time force of the mast, including the static self-weight, its corresponding vertical component during lifting acceleration, and its vertical component during longitudinal acceleration and deceleration. The above forces can be summarized by the following formula.

[0084] G0=W1(g-a2cosβ) In the formula, W1 is the rear axle weight when the gantry is vertically unloaded; a2 is the driving acceleration; β is the slope angle; and g is the acceleration due to gravity.

[0085] G1= X k|k g In the formula X k|k This is the real-time load weight output by the controller after Kalman filtering.

[0086] G2=M2g+M2a1 / cos(α+β)+M2a2tanα In the formula, M2 is the weight of the forks and fork carriage (which can be obtained through weighing or design data, the same below), a1 is the lifting acceleration, which can be calculated from the lifting height data measured by the long angle sensor and the time; α is the mast tilt angle.

[0087] G3 = M3g + M3a2tanα (H < Hc) G3=M3g+M4a1 / cos(α+β)+M3a2tanα(H≥Hc) In the formula, M3 is the total mast weight; M4 is the weight of the remaining masts (excluding the outer mast); Hc is the height of the remaining masts (excluding the outer mast) when they begin to lift; and H is the fork lifting height detected by the sensor.

[0088] Real-time load tilting torque: Mtip=G1[(H+h)sin(α+β)+Lccos(α+β)+Xcosβ] In the formula, H is the lifting height; h is the fork thickness; Lc is the standard load center distance; and X is the front overhang distance.

[0089] Real-time tilting moment of forks and fork carriage: Mf=G2[(H+h)sin(α+β)+d_fcosβ] In the formula, d_f is the horizontal distance from the horizontal component of the center of gravity of the forks and fork carriage to the lower hinge point (i.e., the mast hinge point) when the mast is vertical. The mast hinge point here is concentric with the center of the front axle.

[0090] Real-time gantry tilting moment

[0091]

[0092] In the formula, d_m is the horizontal distance from the horizontal component of the gantry's vertical center of gravity before lifting to the lower hinge point; h_m is the vertical distance from the vertical component of the gantry's center of gravity to the lower hinge point; mi represents the weight of each gantry; zi represents the vertical distance from the vertical component of the center of gravity of the corresponding gantry in dynamic state to the lower hinge point; when the secondary gantry begins to lift, the vertical height of the center of gravity of the middle gantry and the inner gantry increases by H / 2 and H respectively, from which the vertical distance from the vertical component of the composite center of gravity of the entire gantry in dynamic state to the lower hinge point can be calculated.

[0093] Longitudinal anti-rollover moment: Mw = W1(g-a2cosβ)Lcosβ Security determination logic: 1) Determination of height load curve The forklift load curve (i.e., the relationship curve between cargo weight and permissible lifting height) is pre-stored in the forklift control system. Based on the load weight and the load curve, the corresponding maximum lifting height Hmax is obtained. The lifting height H is measured in real time using a long-angle sensor and compared with the maximum lifting height Hmax. If H < Hmax, the forks lift; if H ≥ Hmax, further lifting is prohibited.

[0094] 2) Torque determination When Mtip+Mf+Mm>0.8Mw, a Level 1 warning is issued without any restrictions. When Mtip+Mf+Mm≥0.9Mw, a level two alarm lock is activated, the vehicle stops, and the gantry is prohibited from lifting or tilting, but allowed to descend, until the alarm is cleared and the function is restored.

[0095] In summary, the control method for forklift anti-tipping provided in this application solves the problem of neglecting acceleration component coupling in traditional models through dynamic coupling compensation; it achieves dynamic parameter switching of multi-level masts through multi-level mast piecewise functions and lifting height thresholds, making the model more comprehensive; and it improves parameter accuracy by optimizing the load weight parameters using Kalman filtering and using the filtered load weight. The above technical solution addresses the problem of existing technologies that only analyze and judge stability based on static loads, neglecting the impact of dynamic loads (such as acceleration / braking inertial forces) on structural safety. It comprehensively considers all dynamic variables to achieve torque determination and can also effectively handle sensor data noise and dynamic interference, improving system stability and reliability. The Kalman filtering algorithm is used as the core technology for this step. After obtaining real and reliable data, the safe load is derived through the longitudinal real-time overturning moment formula, and corrected through a dynamic compensation formula during the upward acceleration process.

[0096] This application also provides a control device for preventing forklift rollover, including: a memory configured to store instructions; and a processor configured to retrieve instructions from the memory and, when executing the instructions, to implement the control method for preventing forklift rollover as described above.

[0097] This application also provides a forklift, including: the control device for preventing forklift tipping as described above.

[0098] This application also provides a machine-readable storage medium storing instructions for causing a machine to execute the control method for preventing forklift tipping described above.

[0099] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0100] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0101] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0102] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0103] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0104] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0105] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, 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 technologies, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0106] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0107] The above are merely embodiments of this application and are not intended to limit the scope of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the scope of the claims of this application.

Claims

1. A control method for preventing a forklift from overturning, characterized by, The control method comprises: acquiring real-time working condition parameters of the forklift truck, wherein the real-time working condition parameters comprise a real-time load weight, a driving acceleration of the forklift truck, a lifting acceleration of a fork, a mast tilt angle of a mast, a slope angle of a slope where the forklift truck is located, and a lifting height of the fork; determining a real-time load front tilting moment of the forklift truck according to the real-time load weight, the lifting height, the mast tilt angle, and the slope angle; determining a real-time fork-related front tilting moment of the forklift truck according to a predetermined fork-related weight, the driving acceleration, the lifting acceleration, the mast tilt angle, the slope angle, and the lifting height; determining a real-time mast front tilting moment of the forklift truck according to a predetermined mast weight, the driving acceleration, the mast tilt angle, the slope angle, and the lifting height; determining a real-time longitudinal anti-rollover moment of the forklift truck according to a predetermined empty rear axle weight, the driving acceleration, and the slope angle; performing anti-rollover control on the forklift truck according to the real-time load front tilting moment, the real-time fork-related front tilting moment, the real-time mast front tilting moment, and the real-time longitudinal anti-rollover moment.

2. The control method according to claim 1, characterized by, The acquisition of the real-time load weight comprises: selecting a target lifting pressure-load weight relationship corresponding to the lifting height according to the lifting height; acquiring a lifting pressure of a lifting hydraulic system of the forklift truck; determining a preliminary load weight according to the lifting pressure based on the target lifting pressure-load weight relationship; performing Kalman filtering operation on the preliminary load weight to obtain the real-time load weight.

3. The control method according to claim 1, characterized by, The determination of the real-time load front tilting moment of the forklift truck according to the real-time load weight, the lifting height, the mast tilt angle, and the slope angle comprises: determining a real-time load force according to the real-time load weight; determining the real-time load front tilting moment of the forklift truck according to the real-time load force, the lifting height, the mast tilt angle, and the slope angle; wherein the determination of the real-time load front tilting moment of the forklift truck according to the real-time load force, the lifting height, the mast tilt angle, and the slope angle comprises determination of the real-time load front tilting moment according to the following formula (1): M tip = G1[(H + h) sin (a + b) + L c cos (a + b) + X cos b] (1) Wherein, G1 is the real-time load force, a is the gantry inclination angle, β is the slope angle, H is the lifting height, h is the fork thickness, L c is the standard load center distance of the forklift, X is the front overhang distance of the forklift, M tip is the real-time load front tilting moment.

4. The control method according to claim 1, characterized by, The determination of the real-time fork-related front tilting moment of the forklift truck according to the predetermined fork-related weight, the driving acceleration, the lifting acceleration, the mast tilt angle, the slope angle, and the lifting height comprises: determining a fork-related static gravity according to the predetermined fork-related weight; determining a first lifting acceleration / deceleration vertical component force according to the fork-related weight, the lifting acceleration, the mast tilt angle, and the slope angle; determining a first longitudinal acceleration / deceleration vertical component force according to the fork-related weight, the mast tilt angle, and the driving acceleration; determining a sum of the fork-related static gravity, the first lifting acceleration / deceleration vertical component force, and the first longitudinal acceleration / deceleration vertical component force to obtain a real-time fork-related force. Determine a real-time forklift related front leaning torque of the forklift according to the real-time forklift related force, the lifting height, the mast tilting angle and the slope angle.

5. The control method according to claim 4, characterized by The determining the first lifting acceleration / deceleration vertical component force according to the forklift related weight, the mast tilting angle and the driving acceleration comprises determining the first lifting acceleration / deceleration vertical component force according to the following formula (3): G2 起升 = M2a1 / cos(α+β) (2) The determining the first lifting acceleration / deceleration vertical component force according to the forklift related weight, the mast tilting angle and the driving acceleration comprises determining the first lifting acceleration / deceleration vertical component force according to the following formula (3): G2 纵向 = M2a2tan a (3) The determining the real-time forklift related front leaning torque of the forklift according to the real-time forklift related force, the lifting height, the mast tilting angle and the slope angle comprises determining the real-time forklift related front leaning torque according to the following formula (4): M f = G2[(H + h) sin(a + b) + d_f cos b] (4) Wherein, G2 起升 is the first lifting acceleration vertical component, M2 is the fork related weight, a1 is the lifting acceleration, a is the tilt angle of the mast, b is the slope angle, G2 纵向 is the first longitudinal acceleration vertical component, a2 is the driving acceleration, G2 is the real-time fork related force, H is the lifting height, h is the fork thickness, d_f is the horizontal distance from the horizontal component of the center of gravity of the fork related to the mast hinge point of the forklift, M f is the real-time fork related front tilting torque.

6. The control method according to claim 1, characterized by The mast comprises an outer mast and a non-outer mast, and the mast weight comprises a total mast weight of the outer mast and the non-outer mast and a non-outer mast weight of the non-outer mast; the determining the real-time mast front leaning torque of the forklift according to the predetermined mast weight, the driving acceleration, the mast tilting angle, the slope angle and the lifting height comprises: Determining a mast static gravity according to the total mast weight; Determining a second longitudinal acceleration / deceleration vertical component force according to the total mast weight, the driving acceleration and the mast tilting angle; Determining a second lifting acceleration / deceleration vertical component force according to the non-outer mast weight, the lifting acceleration, the mast tilting angle and the slope angle; In a case that the lifting height is less than a preset lifting height threshold value, determining a sum of the mast static gravity and the second longitudinal acceleration / deceleration vertical component force to obtain a real-time mast force, wherein the preset lifting height threshold value is a lifting height value of the forklift when the non-outer mast starts lifting; In a case that the lifting height is greater than or equal to the preset lifting height threshold value, determining a sum of the mast static gravity, the second longitudinal acceleration / deceleration vertical component force and the second lifting acceleration / deceleration vertical component force to obtain a real-time mast force; Determining a real-time mast front leaning torque of the forklift according to the real-time mast force, the mast tilting angle, the slope angle and the lifting height.

7. The control method according to claim 6, characterized by The determining the second longitudinal acceleration / deceleration vertical component force according to the total mast weight, the driving acceleration and the mast tilting angle comprises determining the second longitudinal acceleration / deceleration vertical component force according to the following formula (5): G3 纵向 = M3a2 tan a (5) The determining the second lifting acceleration / deceleration vertical component force according to the non-outer mast weight, the lifting acceleration, the mast tilting angle and the slope angle comprises determining the second lifting acceleration / deceleration vertical component force according to the following formula (6): G3 起升 = M4a1 / cos(α+β) (6) The determining the real-time mast front leaning torque of the forklift according to the real-time mast force, the mast tilting angle, the slope angle and the lifting height comprises: In a case that the lifting height is less than the preset lifting height threshold value, determining the real-time mast front leaning torque according to the following formula (7): （7） In a case where the lifting height is greater than or equal to the preset lifting height threshold, the real-time gantry tilting moment is determined according to the following formula (8): （8） wherein G3 纵向 is the second longitudinal acceleration / deceleration vertical component, M3 is the total gantry weight, a2 is the travel acceleration, and a is the gantry inclination angle, G3 起升 is the second lifting acceleration / deceleration vertical component, M4 is the non-outer gantry weight, a1 is the lifting acceleration, β is the slope angle, G3 is the real-time gantry force, H is the lifting height, Hc is the preset lifting height threshold, h_m is the vertical distance from the vertical component of the gantry center of gravity to the gantry hinge point, d_m is the horizontal distance from the horizontal component of the gantry center of gravity to the gantry hinge point when the gantry is not lifted vertically, mi represents the weight of the i-th gantry, zi represents the vertical distance from the vertical component of the center of gravity of the i-th gantry in the dynamic state to the gantry hinge point, and n is the total number of gantries, M m is the real-time gantry front-leaning torque.

8. The control method according to claim 1, characterized by, The real-time longitudinal anti-rollover moment of the forklift is determined according to the real-time load tilting moment, the real-time fork-related tilting moment, the real-time gantry tilting moment, and the real-time longitudinal anti-rollover moment, including: M w = W1(g-a2cosβ)Lcosβ(9) wherein M w is the real-time longitudinal anti-rollover moment, W1 is the empty rear axle weight, g is the acceleration of gravity, a2 is the driving acceleration, β is the slope angle, and L is the wheelbase of the forklift.

9. The control method according to claim 1, characterized by, The sum of the real-time load tilting moment, the real-time fork-related tilting moment, and the real-time gantry tilting moment is determined to obtain a total real-time tilting moment; In a case where the total real-time tilting moment is greater than a first preset multiple of the real-time longitudinal anti-rollover moment and less than a second preset multiple of the real-time longitudinal anti-rollover moment, a rollover warning signal is issued, wherein the first preset multiple and the second preset multiple are both less than 1, and the first preset multiple is less than the second preset multiple; In a case where the total real-time tilting moment is greater than or equal to the second preset multiple of the real-time longitudinal anti-rollover moment, the forklift is locked or speed-limited. The control method further includes:

10. The control method according to claim 1, characterized by, According to the real-time load weight, a corresponding current allowable lifting height is determined based on a predetermined correspondence between load weight and allowable lifting height of the fork; In a case where the lifting height is greater than or equal to the current allowable lifting height, the lifting action of the forklift is prohibited; In a case where the lifting height is less than the current allowable lifting height, the lifting action of the forklift is not prohibited. including:

11. A control device for preventing a forklift from overturning, characterized by comprising: a memory configured to store instructions; and a processor configured to call the instructions from the memory and capable of implementing the control method for forklift rollover prevention according to any one of claims 1 to 10 when executing the instructions. including:

12. A fork truck characterized by, The control device for forklift rollover prevention according to claim 11. The machine-readable storage medium has instructions stored thereon for causing a machine to perform the control method for forklift rollover prevention according to any one of claims 1 to 10.

13. A machine-readable storage medium, characterized in that, ​

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