Method and system for monitoring stability of automobile crane

Abstract

The invention relates to the technical field of crane stability monitoring, in particular to an automobile crane stability monitoring method and system.The method comprises the steps that counter-acting force borne by all supporting legs, the inclination angle of a crane operation platform and the weight and acceleration of a hoisting weight during operation of an automobile crane are collected; the method comprises the following steps: acquiring a stability coefficient at each moment by analyzing the real-time change condition of a nominal gravity center on a supporting plane defined by four supporting legs under an overlooking view angle when the crane works; and monitoring the stability of the automobile crane in real time by using the stability coefficient. The invention aims to convert multi-dimensional complex and irregular dynamic physical quantities into one-dimensional changing stability coefficients during stability monitoring of the automobile crane, so that the stability monitoring process is simplified, and the calculation accuracy and real-time performance are improved.

Description

Technical Field

[0001] The present application relates to the technical field of crane stability monitoring, and in particular to a method and system for monitoring the stability of a truck crane. Background Art

[0002] In the process of power construction, truck cranes play a vital role, for example, they are used to hoist power equipment and erect transmission line towers. Truck cranes are a type of crane installed on an ordinary car chassis or a special car chassis, with a driving cab and a lifting control cab separately set. The advantages of this type of crane are good maneuverability and rapid transfer; the disadvantages are that it needs outriggers when working, cannot travel under load, and is not suitable for working on soft or muddy sites. However, due to the complex environment of the power construction site and the existence of many unstable factors, truck cranes face a high risk of overturning during operation. Once a overturning accident occurs, it will not only cause serious damage to the crane itself, but may also endanger the lives of on-site construction workers, leading to delays in power construction projects and huge economic losses.

[0003] The Chinese patent (CN118183535A) discloses a method for determining the equivalent center of gravity of a truck crane based on the working pressure and relative coordinates of each outrigger, setting a threshold according to the warning line, and determining the coordinates of each fulcrum in the warning area based on the relative coordinates of each outrigger, thereby obtaining the warning area, and providing an anti-overturning warning by judging whether the equivalent center of gravity of the truck crane is within the warning area. However, this method only relies on the outrigger pressure and position to determine the equivalent center of gravity, and cannot fully evaluate the dynamic stability of the truck crane, and cannot provide timely and effective warnings during complex actions such as lifting and slewing.

[0004] The Chinese patent (CN119117966A) discloses a method of obtaining the coordinates of the pressure center of the truck crane in the working state in the reference coordinate system, monitoring the zero moment point in real time, calculating the coordinate ratio of the two and taking the maximum value K, and issuing different levels of warnings according to the magnitude of K, 1 and the preset threshold. This method takes the zero moment point into consideration to ensure the stability of the truck crane. However, the mass, center of mass coordinates and acceleration of each component in three directions need to be obtained during the calculation process. In actual operation, it is difficult to obtain these multi-dimensional parameters, which will affect the accuracy of the calculation of the zero moment point and the pressure center, and thus affect the accuracy of the warning.

[0005] In summary, the traditional anti-overturning warning method for truck cranes is to first calculate the nominal center of gravity based on the pressure of the outriggers, and then perform anti-overturning warning for the truck crane based on the change of the center of gravity. However, the traditional center of gravity calculation method has defects, which may lead to deviations in the calculation of the center of gravity, resulting in the inability to timely and effectively perform anti-overturning warning for the truck crane during operation. Summary of the invention

[0006] In order to solve the above technical problems, the present application provides a method and system for monitoring the stability of a truck crane. The technical solutions adopted are as follows: In a first aspect, an embodiment of the present application provides a method for monitoring the stability of a truck crane, the method comprising the following steps: Step 1: Collect the reaction force on each outrigger when the truck crane is operating, the inclination angle of the crane working platform, and the weight and acceleration of the load; Step 2: By analyzing the real-time changes of the nominal center of gravity on the support plane surrounded by the four legs from a bird's-eye view when the crane is operating, the stability coefficient at each moment is obtained; specifically: S1, determine the nominal center of gravity coordinates of the truck crane on the support plane when it is unloaded based on the reaction force on all outriggers when the truck crane is unloaded, the moment arms between all outriggers and the geometric center of the support plane, and the weight of the truck crane when it is unloaded; S2, combining the lifting weight of the truck crane during operation and the reaction force of each leg collected in real time, determines the real-time nominal center of gravity coordinates; S3, combining the inclination change of the platform during the lifting operation, correcting the nominal center of gravity coordinates calculated in real time; S4, combining the nominal center of gravity coordinates when unloaded, the corrected real-time nominal center of gravity coordinates and the range of the support plane, calculates the stability coefficient in real time; Step 3: Use the stability coefficient to monitor the stability of the truck crane in real time.

[0007] Preferably, the support plane has the horizontal rightward direction as the positive half axis of the x-axis and the horizontal upward direction as the positive half axis of the y-axis.

[0008] Preferably, the left and right sides of the supporting plane are parallel to two horizontal upward line segments, which are the front axle and rear axle of the truck crane in a top-down perspective, respectively. The two endpoints on the front axle are the positions of the two front legs, and the two endpoints on the rear axle are the positions of the two rear legs.

[0009] Preferably, the method for determining the nominal center of gravity coordinates of the truck crane when unloaded on the support plane is: The weight of the truck crane when unloaded is used to calculate the gravity of the geometric center, and the moment formula is used to calculate the moment arms of the geometric center of the support plane on the x-axis and y-axis respectively; The lever arms of the geometric center of the supporting plane on the x-axis and y-axis are respectively used as the x-axis coordinate and y-axis coordinate of the nominal center of gravity of the truck crane when it is unloaded.

[0010] Preferably, the difference between the determination method of the real-time nominal center of gravity coordinates and the nominal center of gravity coordinates when unloaded is that the gravity of the geometric center is calculated by the sum of the weight of the crane when it is operating and the weight when it is unloaded.

[0011] Preferably, the calculation method for correcting the nominal center of gravity coordinates calculated in real time in combination with the inclination change of the platform during the lifting operation is: The correction coefficient in the x-axis direction at time t is recorded as , ; In the formula, represents the equivalent offset force in the x-axis direction at time t, represents the weight of the load at time t, represents the acceleration of the load in the x-axis direction at time t, , , and They represent the reaction forces on each leg at time t; Among them, the correction coefficient in the y-axis direction at time t is The calculation method and The calculation method is the same as in The calculation method involves replacing the x-axis with the y-axis; The correction factor and Add them to the x-axis coordinate and y-axis coordinate of the nominal center of gravity calculated at time t respectively to obtain the corrected nominal center of gravity coordinate at time t.

[0012] Preferably, ; In the formula, represents the equivalent offset force in the x-axis direction at time t, It represents the sum of the empty weight of the truck crane and the weight of the load. g represents the acceleration due to gravity. Indicates the angle of the work platform in the x-axis direction, Indicates the distance between the outriggers of the truck crane on the x-axis.

[0013] Preferably, the real-time calculation method of the stability coefficient is: The stability coefficient at time t is expressed as , ; In the formula, norm() represents the normalization function, It indicates the minimum value of the distance between the nominal center of gravity of the truck crane and each side of the support plane when it is unloaded. It represents the minimum value of the distance between the nominal center of gravity and each side of the support plane at time t. Represents the diagonal length of the support plane.

[0014] Preferably, the method for real-time monitoring of the stability of the truck crane using the stability coefficient is: When the stability coefficient is less than or equal to the stability threshold, the current truck crane is at risk of overturning; On the contrary, there is no risk of overturning of the current truck crane.

[0015] In a second aspect, the embodiment of the present application further provides a vehicle crane stability monitoring system, comprising: The truck crane operation data collection module is used to collect the reaction force on each outrigger during the operation of the truck crane, the inclination angle of the crane operating platform, and the weight and acceleration of the hoisted load; The operation data processing module is used to obtain the stability coefficient at each moment by analyzing the real-time changes of the nominal center of gravity on the support plane surrounded by four outriggers when the crane is operating from a bird's-eye view; On-board display screen for real-time monitoring of the stability of the truck crane using the stability factor.

[0016] This application has at least the following beneficial effects: The present application determines the real-time nominal center of gravity coordinates in combination with the weight of the load being lifted during the operation of the truck crane and the reaction force of each leg collected in real time. By tracking the range of changes in the nominal center of gravity coordinates of the crane, the overturning risk under different lifting weights and working positions can be evaluated to ensure the safe operation of the crane during complex operations. The nominal center of gravity coordinates calculated in real time are corrected in combination with the change in the inclination angle of the platform during the lifting operation. Based on the principle of mechanics, the correction coefficient obtained by using the change in the inclination angle of the working platform during the operation of the truck crane and the equilibrium state is used to quantify this change, and the influence of the center of gravity offset on the nominal center of gravity coordinates is characterized. The nominal center of gravity coordinates when unloaded, the corrected real-time nominal center of gravity coordinates and the range of the support plane are combined to calculate the stability coefficient in real time, analyze whether the nominal center of gravity is closer to the boundary, thereby reducing the stability of the crane, and judge the risk of overturning of the truck crane in real time. By monitoring the stability of truck cranes of different models, the common characteristics of the unstable state of truck cranes are explored, which is conducive to realizing the stability monitoring of truck cranes of different models according to actual needs during the power construction process, and greatly improves the efficiency of truck crane monitoring. At the same time, the theoretical analysis is combined with the relevant data of real-time measurement of the operation of the truck crane, and the complex and irregular dynamic physical quantities with multi-dimensional changes are converted into a one-dimensional stability coefficient, which simplifies the stability monitoring process and improves the accuracy and real-time performance of the calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 A flow chart of a method for monitoring the stability of a truck crane provided in this application; Figure 2 A schematic diagram of a support plane composed of four legs when a crane provided by an embodiment of the present application is operating from a top view; Figure 3 A flow chart of a method for obtaining the stability coefficient at each moment provided in this application. DETAILED DESCRIPTION

[0019] In order to further explain the technical means and effects adopted by the present application to achieve the predetermined invention purpose, the following is a detailed description of a method and system for monitoring the stability of a truck crane proposed in the present application, its specific implementation, structure, features and effects, in combination with the accompanying drawings and preferred embodiments. In the following description, different "one embodiment" or "another embodiment" does not necessarily refer to the same embodiment. In addition, specific features, structures or characteristics in one or more embodiments may be combined in any suitable form.

[0020] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

[0021] The specific scheme of a truck crane stability monitoring method and system provided by the present application is described in detail below with reference to the accompanying drawings.

[0022] An embodiment of the present application provides a method and system for monitoring the stability of a truck crane.

[0023] Specifically, a method for monitoring the stability of a truck crane is provided as follows. Figure 1 , the method comprises the following steps: Step 1: Collect the reaction force on each leg of the truck crane, the inclination angle of the crane working platform, and the weight and acceleration of the load when the truck crane is in operation.

[0024] This embodiment takes the XCMG QY25K5C truck crane as an example. The truck crane has four outriggers. The lateral distance between the outriggers is 6 meters, the longitudinal distance is 5.14 meters, the maximum mass of the whole machine in the driving state is 31750kg, the maximum rated lifting weight is 25T, and the minimum rated amplitude is 3 meters. The support plane diagram surrounded by the four outriggers when the crane is operating from a top-down perspective is as follows: Figure 2 shown.

[0025] exist Figure 2 In the figure, the geometric center of the support plane is defined as the coordinate zero point O (0.0, 0.0), the horizontal right direction is the positive semi-axis of the x-axis, the horizontal upward direction is the positive semi-axis of the y-axis, and the left and right sides of the support plane are parallel to the two horizontal upward line segments, which are the front axle and rear axle of the truck crane in the top view, that is, the straight line AB is the front axle of the truck crane, and the straight line CD is the rear axle of the truck crane. The coordinates of the force points of the four outriggers of the truck crane are A (-2.57, 3.0), B (-2.57, -3.0), C (2.57, -3.0), and D (2.57, 3.0), and the reaction forces are FA, FB, FC, and FD, respectively. At the same time, it is stipulated that the vertical ground is upward as the positive direction of the reaction force. Among them, the coordinates A and B are the positions of the two front outriggers of the truck crane, and the coordinates C and D are the positions of the two rear outriggers of the truck crane.

[0026] Pressure sensors are installed on the pads of each leg to measure the reaction force of each leg in real time. An inclination sensor is installed at the center of the crane operating platform to measure the inclination changes of the crane in the x-axis and y-axis directions in real time. A weight sensor and an acceleration sensor are installed on the boom to measure the weight of the load and its acceleration in the x-axis and y-axis under the lifting state.

[0027] In this embodiment, the sampling frequency of the sensor is 10 Hz. The collected data is cleaned and interpolated to remove abnormal data. Data cleaning and data interpolation belong to well-known technologies and the specific contents will not be repeated here.

[0028] Step 2: Obtain the stability coefficient at each moment by analyzing the real-time changes of the nominal center of gravity on the support plane surrounded by the four legs from a bird's-eye view when the crane is operating.

[0029] In an object system, if the resultant force on a certain point is zero, then this point is called a zero moment point. For a truck crane, after selecting a suitable coordinate origin in its support plane, the sum of the moments of the reaction forces of each leg and the crane's own gravity on this point should be zero in a balanced state. Through this theory, the mathematical relationship between each force and the lever arm can be established, so as to solve the coordinates of the nominal center of gravity of the crane. When the position of the nominal center of gravity changes and approaches the dangerous boundary of the support plane, it means that the balance state of the crane is broken and there is a possibility of overturning.

[0030] In this application, the flow chart of the method for obtaining the stability coefficient at each moment is as shown in the attached Figure 3 As shown, specifically: S1. Determine the coordinates of the nominal center of gravity of the unloaded truck crane on the supporting plane based on the reaction forces on all outriggers when the truck crane is unloaded, the moment arms between all outriggers and the geometric center of the supporting plane, and the weight of the unloaded truck crane.

[0031] When the crane is unloaded, the load and reaction force of each leg are calculated based on the axle load of the crane based on the principle of mechanical balance. The weight G of the crane when unloaded is equal to the sum of the axle loads, G=31.750 tons. According to the design of the crane, the front axle load is known. Tons, rear axle load Tons, according to the principle of mechanical distribution, the load distributed to the front outrigger is tons, the load distributed to the rear outriggers is Tons, the reaction force received is calculated according to the load of each leg, that is, the direction is opposite to the gravity. In this embodiment, the gravity acceleration is g=9.8N / kg, and the gravity of the truck crane when it is unloaded is obtained.

[0032] Then calculate the moment of the coordinate origin O in the support plane. In the x-axis direction, the force arm of the front legs A and B is the distance from the coordinate origin, that is, m, the lever arms of the rear outriggers C and D are m, assuming that the force arm of the crane's center of gravity in the x-axis direction is rice.

[0033] The moment of the coordinate origin O is calculated according to the moment formula. The moment formula belongs to the well-known technology and the specific content is not repeated here.

[0034] According to the zero moment point theory, the resultant moment in the x-axis direction is 0, so let , solve Meters, which means the arm of the nominal center of gravity of the truck crane in the x-axis direction. , , , and They represent the moments at points A, B, C, D and the coordinate origin O of the truck crane in the x-axis direction respectively.

[0035] Similarly, in the y-axis direction, the force arm of the right legs A and D is m, the lever arms of the left legs B and C are m, assuming that the arm of the nominal center of gravity of the truck crane in the y-axis direction is Rice, solve Meter, which means the arm of the nominal center of gravity of the truck crane in the y-axis direction.

[0036] From the above calculation, we can get the coordinates of the nominal center of gravity of the truck crane in the support plane when it is not lifting: .

[0037] S2, combining the lifting weight of the truck crane during operation and the reaction force of each leg collected in real time, determines the real-time nominal center of gravity coordinates.

[0038] During the lifting process, the nominal center of gravity of the crane will change with the increase of the lifting weight and the change of position. The nominal center of gravity position when no-load is the starting point of subsequent changes. By comparing the difference between the nominal center of gravity position under different working conditions and when no-load, the stability changes and overturning risks of the crane can be effectively evaluated.

[0039] When the crane is lifting, the reaction force of each leg will change, causing the nominal center of gravity to move. Therefore, it is necessary to establish a new moment balance equation based on the data collected by the sensor in real time, so as to calculate the real-time nominal center of gravity coordinates. Suppose the nominal center of gravity coordinates during lifting are , taking time t as an example, from the above analysis we can see that: In the formula, It represents the arm of the nominal center of gravity of the truck crane in the x-axis direction at time t under the lifting state, that is, the x-axis coordinate of the nominal center of gravity at time t. , , and They represent the reaction forces on each leg at time t, , , and Respectively represent the arm of each leg in the x-axis direction, which are fixed values ​​in this embodiment, and are the distances from points A, B, C and D to the geometric center of the support plane in the x-axis direction. is the sum of the gravity of the truck crane when it is unloaded and the gravity of the load. Similarly, the y-axis coordinate of the nominal center of gravity of the truck crane at time t under the load state can be calculated: .

[0040] It should be understood that in the lifting state, the gravity of the load will have different effects on each leg of the crane. Therefore, during the lifting process, the reaction force on each leg will continue to change, causing the nominal center of gravity of the truck crane to continue to change. By tracking the range of change of the nominal center of gravity coordinates of the crane, the overturning risk under different lifting loads and operating positions can be evaluated to ensure the safe operation of the crane during complex operations.

[0041] S3, combining the inclination change of the platform during the lifting operation, corrects the nominal center of gravity coordinates calculated in real time.

[0042] The above analysis is calculated based on the zero moment point theory of rigid body equilibrium. Rigid body equilibrium refers to the state in which a rigid body remains stationary or moves in a uniform linear motion under the action of a force system. For a truck crane, equilibrium needs to meet two conditions: one is that the resultant force is zero, that is, the vector sum of all forces acting on the rigid body in all directions is zero; the other is that the resultant moment is zero, that is, for any point on the rigid body, the algebraic sum of the moments of all forces on that point is zero.

[0043] However, in actual work, the truck crane is not an ideal rigid body, so it is necessary to use the data measured by the inclination sensor installed on the working platform to correct the reaction force of the outrigger, increase the influence of the unstable factors caused by the inclination on the outrigger force, and thus reflect the influence of the platform inclination on the nominal center of gravity position of the truck crane.

[0044] Specifically, when the platform has an inclination angle in the x-axis direction When the crane's center of gravity is offset in the x-axis direction, it is equivalent to an additional force on the outrigger plane. According to the principle of mechanics, the gravity generated by the overall mass is decomposed along the inclination direction, and then normalized by the lateral distance of the outrigger to obtain this equivalent offset force. It reflects the influence of the instability factor in the x-axis direction caused by the inclination angle on the outrigger force, and is used to subsequently correct the calculation of the outrigger reaction force in the x-axis direction.

[0045] Furthermore, in a stationary state, the gravity of the truck crane, that is, the sum of the gravity of the crane when it is unloaded and the gravity of the load, is equal to the reaction force of the four legs of the crane. However, during the lifting process, the load has acceleration. At this time, the gravity of the truck crane is different from the reaction force of the four legs. Because there is a resultant external force in the whole system, in order to avoid overturning caused by the resultant external force, it should be considered when calculating the correction coefficient. Taking time t as an example, the calculation method of the correction coefficient is: In the formula, It represents the correction coefficient in the x-axis direction at time t. represents the equivalent offset force in the x-axis direction at time t, represents the weight of the load at time t, represents the acceleration of the load in the x-axis direction at time t, , , and They respectively represent the reaction forces received by each leg at time t.

[0046] in, ; In the formula, represents the equivalent offset force in the x-axis direction at time t, It represents the effective mass, which is the sum of the weight of the empty truck crane and the weight of the load. g represents the acceleration due to gravity. Indicates the angle of the work platform in the x-axis direction, It indicates the distance between the outriggers of the truck crane on the x-axis, that is, the distance between the front and rear axles of the truck crane. If the equivalent offset force is larger, it means that the platform inclination angle has a greater impact on the nominal center of gravity of the truck crane, so the coordinates of the nominal center of gravity should be corrected. On the contrary, it means that the platform inclination angle has a smaller impact on the nominal center of gravity of the truck crane, so it should not be corrected.

[0047] It should be understood that the correction coefficient represents the proportion of the x-axis equivalent offset force in the total outrigger reaction force. Through this proportional coefficient, the degree of correction of the nominal center of gravity coordinate calculated in the x-axis direction due to the x-axis inclination can be reasonably adjusted according to the actual situation of the current outrigger reaction force. The larger the correction coefficient, the greater the influence of the platform inclination on the nominal center of gravity of the truck crane, so the more the nominal center of gravity coordinate should be corrected. On the contrary, the smaller the influence of the platform inclination on the nominal center of gravity coordinate, the smaller the range of correction.

[0048] Similarly, calculate the correction coefficient in the y-axis direction at time t , replace the inclination angle in the formula Replaced by the inclination angle of the platform in the y-axis direction , Replaced with the distance between the outriggers of the truck crane on the t-axis, Just replace it with the acceleration of the weight in the y-axis direction.

[0049] The correction coefficient is based on the principle of mechanics. It uses the change in the inclination angle of the working platform and the correction coefficient obtained during the operation of the truck crane to quantify this change and characterize the influence of the center of gravity offset on the nominal center of gravity coordinates. Therefore, the correction coefficient can be used to correct the nominal center of gravity coordinates at time t. After correction, the nominal center of gravity coordinates at time t are .

[0050] S4, calculates the stability coefficient in real time by combining the nominal center of gravity coordinates when unloaded, the corrected real-time nominal center of gravity coordinates, and the range of the support plane.

[0051] During the lifting process, the coordinate position of the nominal center of gravity of the truck crane keeps changing. When the nominal center of gravity is within the area surrounded by the four supporting points of the supporting plane, the crane will not overturn. However, the closer it is to the edge of the area, the greater the risk of overturning.

[0052] Therefore, the stability coefficient is calculated according to the change range of the real-time nominal center of gravity coordinates during the lifting process, as well as the nominal center of gravity coordinates and area range when unloaded. Taking time t as an example, the calculation method of the stability coefficient is: In the formula, represents the stability coefficient at time t, norm() represents the normalization function, It indicates the minimum value of the distance between the nominal center of gravity of the truck crane and each side of the support plane when it is unloaded. It represents the minimum value of the distance between the nominal center of gravity and each side of the support plane at time t. Represents the diagonal length of the support plane.

[0053] It should be understood that the diagonal length of the area enclosed by the support plane is used as a reference scale because it represents the maximum spatial span of the support area and can provide a unified and representative standard for measuring the nominal center of gravity offset. It indicates the change in the distance from the nominal center of gravity to the nearest boundary after lifting relative to the nominal center of gravity when unloaded. When this change increases, it means that the lifting makes the nominal center of gravity closer to the boundary, the stability of the crane decreases, and the value decreases accordingly; on the contrary, if the change decreases or is negative, that is, the nominal center of gravity is farther away from the boundary after lifting, then the value increases, indicating that the stability is enhanced. If the stability coefficient is smaller, it means that the lifting causes the nominal center of gravity to be greatly close to the boundary of the support area, and the stability of the crane is lower, that is, the risk of overturning of the truck crane is higher at this time. On the contrary, it means that the change of the nominal center of gravity in the lifting state is smaller, that is, the closer to the nominal center of gravity when unloaded, the higher the stability of the crane, that is, the lower the risk of overturning of the truck crane at this time.

[0054] Step 3: Use the stability coefficient to monitor the stability of the truck crane in real time.

[0055] When monitoring the stability of the XCMG QY25K5C truck crane, it is determined whether the stability coefficient calculated in real time is less than a preset stability threshold value. In this embodiment, the value is 0.2, which is specifically set by the implementer.

[0056] When the stability coefficient is less than or equal to the stability threshold, the current truck crane is at risk of overturning, and an alarm is issued to remind the staff that the current truck crane is at great risk of overturning; otherwise, the current truck crane is not at risk of overturning.

[0057] In addition, the position of the nominal center of gravity during the lifting process can also be displayed in real time on the vehicle display screen to provide auxiliary judgment for the staff.

[0058] Based on the same inventive concept as the above method, an embodiment of the present application further provides a truck crane stability monitoring system, including a truck crane operation data acquisition module, an operation data processing module and a vehicle-mounted display screen.

[0059] The truck crane operation data collection module is used to collect the reaction force on each outrigger during the operation of the truck crane, the inclination angle of the crane operating platform, and the weight and acceleration of the hoisted load; The operation data processing module is used to obtain the stability coefficient at each moment by analyzing the real-time changes of the nominal center of gravity on the support plane surrounded by four outriggers when the crane is operating from a bird's-eye view; On-board display screen for real-time monitoring of the stability of the truck crane using the stability factor.

[0060] The various embodiments in the present application are described in a progressive manner, and the same or similar parts between the various embodiments can be referenced to each other, and each embodiment focuses on the differences from other embodiments.

[0061] It should be noted that, unless otherwise specified and limited, terms such as "include", "comprises" or any other variants thereof are intended to cover non-exclusive inclusion, so that a circuit structure, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such article or device. In the absence of further restrictions, an element defined by the sentence "including one..." does not exclude the existence of other identical elements in the article or device including the element. In addition, the term "and\or" used herein includes any and all combinations of one or more related listed items.

[0062] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary technical means in the art that are not invented by the present application.

[0063] It should be understood that the present application is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A method for monitoring the stability of a truck crane, characterized in that: The method comprises the following steps: Step 1: Collect the reaction force on each outrigger when the truck crane is operating, the inclination angle of the crane working platform, and the weight and acceleration of the load; Step 2: By analyzing the real-time changes of the nominal center of gravity on the support plane surrounded by the four legs from a bird's-eye view when the crane is operating, the stability coefficient at each moment is obtained; specifically: S1, determine the nominal center of gravity coordinates of the truck crane on the support plane when it is unloaded based on the reaction force on all outriggers when the truck crane is unloaded, the moment arms between all outriggers and the geometric center of the support plane, and the weight of the truck crane when it is unloaded; S2, combining the lifting weight of the truck crane during operation and the reaction force of each leg collected in real time, determines the real-time nominal center of gravity coordinates; S3, combining the inclination change of the platform during the lifting operation, correcting the nominal center of gravity coordinates calculated in real time; S4, combining the nominal center of gravity coordinates when unloaded, the corrected real-time nominal center of gravity coordinates and the range of the support plane, calculates the stability coefficient in real time; Step 3: Use the stability coefficient to monitor the stability of the truck crane in real time.

2. A method for monitoring the stability of a truck crane as claimed in claim 1, characterized in that: The support plane has the horizontal rightward direction as the positive half axis of the x-axis and the horizontal upward direction as the positive half axis of the y-axis.

3. A method for monitoring the stability of a truck crane as claimed in claim 2, characterized in that: The left and right sides of the support plane are parallel to two horizontal upward line segments, which are the front axle and rear axle of the truck crane in a top-down perspective. The two end points on the front axle are the positions of the two front outriggers, and the two end points on the rear axle are the positions of the two rear outriggers.

4. A method for monitoring the stability of a truck crane as claimed in claim 2, characterized in that: The method for determining the nominal center of gravity coordinates of the truck crane when it is unloaded on the support plane is: The weight of the truck crane when unloaded is used to calculate the gravity of the geometric center, and the moment formula is used to calculate the moment arms of the geometric center of the support plane on the x-axis and y-axis respectively; The lever arms of the geometric center of the supporting plane on the x-axis and y-axis are respectively used as the x-axis coordinate and y-axis coordinate of the nominal center of gravity of the truck crane when it is unloaded.

5. A method for monitoring the stability of a truck crane as claimed in claim 4, characterized in that: The difference between the determination method of the real-time nominal center of gravity coordinates and the nominal center of gravity coordinates when unloaded is that the gravity of the geometric center is calculated by the sum of the weight of the load when the truck crane is in operation and the weight when unloaded.

6. A method for monitoring the stability of a truck crane as claimed in claim 2, characterized in that: The calculation method for correcting the nominal center of gravity coordinates calculated in real time in combination with the change in the inclination angle of the platform during the lifting operation is: The correction coefficient in the x-axis direction at time t is recorded as , ; In the formula, represents the equivalent offset force in the x-axis direction at time t, represents the weight of the load at time t, represents the acceleration of the load in the x-axis direction at time t, , , and They represent the reaction forces on each leg at time t; Among them, the correction coefficient in the y-axis direction at time t is The calculation method and The calculation method is the same as in The calculation method involves replacing the x-axis with the y-axis; The correction factor and Add them to the x-axis coordinate and y-axis coordinate of the nominal center of gravity calculated at time t respectively to obtain the corrected nominal center of gravity coordinate at time t.

7. A method for monitoring the stability of a truck crane as claimed in claim 6, characterized in that: ; In the formula, represents the equivalent offset force in the x-axis direction at time t, It represents the sum of the empty weight of the truck crane and the weight of the load. g represents the acceleration due to gravity. Indicates the angle of the work platform in the x-axis direction, Indicates the distance between the outriggers of the truck crane on the x-axis.

8. A method for monitoring the stability of a truck crane as claimed in claim 1, characterized in that: The real-time calculation method of the stability coefficient is: The stability coefficient at time t is expressed as , ; In the formula, norm() represents the normalization function, It indicates the minimum value of the distance between the nominal center of gravity of the truck crane and each side of the support plane when it is unloaded. It represents the minimum value of the distance between the nominal center of gravity and each side of the support plane at time t. Represents the diagonal length of the support plane.

9. A method for monitoring the stability of a truck crane as claimed in claim 1, characterized in that: The method for real-time monitoring of the stability of the truck crane using the stability coefficient is as follows: When the stability coefficient is less than or equal to the stability threshold, the current truck crane is at risk of overturning; On the contrary, there is no risk of overturning of the current truck crane.

10. A truck crane stability monitoring system, implementing the method according to any one of claims 1 to 9, characterized in that: The system includes: The truck crane operation data collection module is used to collect the reaction force on each outrigger when the truck crane is operating, the inclination angle of the crane operating platform, and the weight and acceleration of the load; The operation data processing module is used to obtain the stability coefficient at each moment by analyzing the real-time changes of the nominal center of gravity on the support plane surrounded by four outriggers when the crane is operating from a bird's-eye view; On-board display screen for real-time monitoring of the stability of the truck crane using the stability factor.

Images