Method for judging stability of whole automobile crane

Abstract

The invention discloses a method for judging the overall stability of an automobile crane. The method comprises the following steps: calculating a critical pressure difference Smin of a to-be-analyzed automobile crane in a stable working state in a theoretical state; the method comprises the following steps: detecting pressure values of four support legs of the to-be-analyzed automobile crane in real time by using a pressure sensor, calculating an absolute value S1 of a pressure difference between a support leg A and a support leg C and an absolute value S2 of a pressure difference between a support leg B and a support leg D, and taking a maximum value S of the two values as follows: S = max (S1, S2); s represents the maximum value of the pressure difference borne by the two supporting legs, located at the diagonal positions, of the to-be-analyzed automobile crane in the actual working state; when it is monitored that the value of the maximum value S is larger than Smin or the pressure borne by any supporting leg is zero, an operation stop warning is sent out to the to-be-analyzed automobile crane.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile cranes, and in particular to a method for judging the stability of an automobile crane. Background Art

[0002] Crane anti-overturning stability is one of the important conditions for crane safety operation. Truck cranes are suitable for lifting heavy components and short-cycle operations due to their wide range of applications, good mobility, and the convenience of moving sites. However, truck cranes have high requirements for roads and sites during operation, and are prone to overall overturning, causing property losses and personal injuries. Therefore, it is necessary to study the anti-overturning stability of truck cranes to ensure the safety of the operation process and reduce the risk of accidents.

[0003] In confined space conditions, truck cranes are limited by space and obstacles at certain construction sites, and their outriggers may not be able to fully extend. In the related art, a rated total lifting weight table is generally used to determine the stability of a truck crane. This solution is generally applicable to the stability analysis of the entire machine when the outriggers of a truck crane are fully extended. However, in confined space conditions, since the outriggers of a truck crane cannot be fully extended, the support area is reduced, which directly affects the stability of the crane. At this time, the traditional rated total lifting weight table cannot accurately reflect the actual stability situation, because this method assumes that the outriggers can be fully extended to provide maximum support, and this assumption does not hold true in confined spaces. Therefore, this method cannot accurately reflect the actual stability situation of a truck crane in confined space conditions.

[0004] Therefore, in order to give full play to the lifting capacity of the crane and ensure the safety of the lifting work, it is necessary to provide a method for judging the stability of the entire truck crane in a confined space. Summary of the invention

[0005] The present specification provides a method for determining the stability of a truck crane, so as to overcome at least one technical problem existing in the related art.

[0006] According to an embodiment of the present specification, a method for determining the stability of a truck crane is provided, comprising:

[0007] S1. Calculate the concentrated force P and moment M acting on the frame rotation center of the truck crane to be analyzed by the following formula; wherein the truck crane to be analyzed has four legs, marked as A, B, C and D respectively; wherein legs A and C are in a diagonal direction, and legs B and D are in another diagonal direction, and the truck crane to be analyzed operates in a confined space;

[0008] P=G B +Gc +G P +Q

[0009] M=QR+G c L c +P W L b sinα-G P L P

[0010] Among them, the symbol G B Indicates the mass of the truck crane to be analyzed, symbol: kg, symbol G c Indicates the boom mass of the truck crane to be analyzed, unit: kg; symbol G P = represents the counterweight mass of the truck crane to be analyzed, unit: kg; symbol Q represents the lifting weight of the truck crane to be analyzed, symbol: kg; symbol R represents the working range of the truck crane to be analyzed, unit: m; symbol L c P represents the distance between the center of mass of the boom of the truck crane to be analyzed and the slewing axis, unit: m; symbol: W It represents the wind load on the truck crane to be analyzed, symbol L b Indicates the boom length of the truck crane to be analyzed, length: m; symbol G P Indicates the counterweight mass of the truck crane to be analyzed, symbol: kg; symbol L P represents the distance between the center of mass of the counterweight of the truck crane to be analyzed and the slewing axis, unit: m; symbol α represents the slewing angle of the truck crane to be analyzed, symbol: rad;

[0011] S2. Take the rotation center of the truck crane to be analyzed as the coordinate origin, the direction from the coordinate origin to the front of the truck crane as the X-axis direction, and the direction from the coordinate origin to the front of the truck crane as the Y-axis direction. Calculate the torque M of the truck crane to be analyzed rotating around the X-axis based on the following formula: x and the moment M about the X axis y :

[0012] M x =Msinβ,M y =Mcosβ

[0013] Wherein, the symbol β represents the working angle of the truck crane to be analyzed, symbol: rad.

[0014] S3. Calculate the force F acting on the A leg of the truck crane to be analyzed by the following formula: A , the force F at the B leg B , the force F at the C legC and the force F acting on the D leg D :

[0015]

[0016] Among them, the symbol G D Indicates the unloading mass of the truck crane to be analyzed, symbol: kg, symbol e b The symbol e represents the truck crane to be analyzed. h represents the truck crane to be analyzed, symbol a1 represents the extended length of the A outrigger of the truck crane to be analyzed, symbol a2 represents the extended length of the B outrigger of the truck crane to be analyzed, symbol a3 represents the extended length of the C outrigger of the truck crane to be analyzed, symbol a4 represents the extended length of the D outrigger of the truck crane to be analyzed, and symbol b represents the longitudinal span of the outriggers of the truck crane to be analyzed;

[0017] S4. Calculate the absolute value F of the pressure difference between the outriggers A and C of the truck crane to be analyzed by the following formula: AC , and the absolute value F of the pressure difference between leg B and leg D BD :

[0018]

[0019] Get the absolute value F AC and the absolute value F BD The maximum value S min , the maximum value S min is the critical pressure difference of the truck crane to be analyzed in a stable working state under a theoretical state;

[0020] S min =max(F AC ,F BD )

[0021] S5. Use a pressure sensor to detect the pressure values ​​of the four outriggers of the truck crane to be analyzed in real time, and calculate the absolute value S1 of the pressure difference between outrigger A and outrigger C, and the absolute value S2 of the pressure difference between outrigger B and outrigger D, and take the maximum value S=max(S1, S2); S represents the maximum value of the pressure difference of the two outriggers in the diagonal position of the truck crane to be analyzed in the actual working state; when the value of the maximum value S is greater than the maximum value S min Or when the pressure on any leg is zero, a warning to stop operation is issued to the truck crane to be analyzed.

[0022] The beneficial effects of the embodiments of this specification are as follows: Considering that the outriggers of a truck crane operating in a confined space cannot be fully extended, resulting in a reduction in its support area, the technical solution of this application provides a criterion for judging whether the truck crane will become unstable when operating in a confined space. In the technical solution of this application, the pressure difference between the two outriggers on the diagonal line of the truck crane is monitored in real time, and the uneven pressure distribution can be detected in time, thereby judging whether the crane is in a stable state. If the pressure of a certain outrigger drops to zero or the pressure difference exceeds the preset safety threshold S min , it means that the crane may be close to an unstable state. At this time, it is necessary to activate the alarm mechanism or stop the operation to prevent accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of this specification or related technologies, the drawings required for use in the embodiments or related technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 This is a schematic diagram of a crane modeled in a method for determining the stability of a truck crane provided in an embodiment of this specification;

[0025] Figure 2 A schematic diagram showing a method for judging the stability of a truck crane provided in an embodiment of this specification, in which the four legs of the crane are in a fully extended state;

[0026] Figure 3 A method for determining the stability of a truck crane provided in one embodiment of the present specification is a schematic diagram showing that some legs of the crane are not in a fully extended state. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of this specification will be described clearly and completely below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention. It should be noted that the terms "including" and "having" in the embodiments of this specification and the drawings, as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not limited to the listed steps or units, but optionally also includes steps or units that are not listed, or optionally also includes other steps or units that are inherent to these processes, methods, products or devices.

[0028] The background technology section above records that it is necessary to study the anti-overturning stability of truck cranes in order to ensure the safety of the operation process and reduce the risk of accidents. In the related art, a rated total lifting weight table is generally used to determine the stability of a truck crane. This solution is generally applicable to the stability analysis of the entire machine when the outriggers of the truck crane are fully extended. However, in confined space conditions, since the outriggers of the truck crane cannot be fully extended, the support area is reduced, which directly affects the stability of the crane. At this time, the traditional rated total lifting weight table cannot accurately reflect the actual stability situation, because this method assumes that the outriggers can be fully extended to provide maximum support, and this assumption does not hold true in confined spaces.

[0029] In response to the technical problems existing in the prior art, the technical solution of the present application proposes a criterion that can determine whether a truck crane operating in a confined space is in a stable state, which can more accurately evaluate the actual safety status of the truck crane operating in a confined space.

[0030] The specific steps of the method for judging the stability of the truck crane provided by the technical solution of this application are as follows:

[0031] Step S1: Calculate the concentrated force P and moment M acting on the frame rotation center of the truck crane to be analyzed by the following formula; wherein the truck crane to be analyzed has four legs, which are marked as A, B, C and D respectively; wherein the legs A and C are in a diagonal direction, and the legs B and D are in another diagonal direction, and the truck crane to be analyzed operates in a confined space;

[0032] P=G B +G c +G P +Q

[0033] M=QR+G c L c+P W L b sinα-G P L P

[0034] Among them, the symbol G B Indicates the mass of the truck crane to be analyzed, symbol: kg, symbol G c Indicates the boom mass of the truck crane to be analyzed, unit: kg; symbol G P Indicates the counterweight mass of the truck crane to be analyzed, unit: kg; symbol Q indicates the lifting weight of the truck crane to be analyzed, symbol: kg; symbol R indicates the working range of the truck crane to be analyzed, unit: m; symbol L c It represents the distance between the center of mass of the boom of the truck crane to be analyzed and the slewing axis, unit: m; symbol P W Indicates the wind load on the truck crane to be analyzed, symbol L b Indicates the boom length of the truck crane to be analyzed, length: m; symbol G P Indicates the counterweight mass of the truck crane to be analyzed, symbol: kg; symbol L P It represents the distance between the center of mass of the counterweight of the truck crane to be analyzed and the slewing axis, unit: m; the symbol α represents the slewing angle of the truck crane to be analyzed, symbol: rad.

[0035] In this step, confined space refers to the space constraints encountered by the truck crane during operation, such as a small space or obstacles that prevent the outriggers from fully extending. In this case, the stability and safety of the truck crane will be affected because the outriggers cannot be fully extended to provide sufficient support area, thereby increasing the risk of overturning. Figure 2 and Figure 3 As shown, in Figure 2 In the figure, the crane's four legs A, B, C and D are fully extended. Figure 3 The A and B outriggers of the crane are not fully extended. B The load Q, wind load Pw and the torque generated by them are all transmitted to the frame through the slewing support. This is because the slewing support is a key component connecting the crane superstructure (including the boom, etc.) and the lower frame. It can not only support the weight of the superstructure, but also transmit various forces and torques generated by the superstructure during operation to the frame. B It is usually a parameter determined when a truck crane is designed. The specific value can be obtained by referring to the technical manual of the truck crane model.

[0036] like Figure 1 As shown, Figure 1This is a schematic diagram of a crane modeled in a method for determining the stability of a truck crane provided in an embodiment of this specification. For the convenience of calculation, it is assumed that the truck crane body and the boom are rigid bodies, the ground foundation is a rigid structure, and the hoisted object is regarded as a point mass. The distance between the center lines of the outriggers is ignored; the center of gravity of each section of the boom is ignored, and the friction torque generated during the rotation process is ignored. During the lifting operation, the truck crane is supported by four outriggers, and the geometric center of the outrigger support coincides with the center of rotation. When the truck crane is in operation, the deadweight of the vehicle G B , load Q and wind load P W (The torque generated by the upper and lower vehicles is transmitted to the frame through the slewing support. This is because the slewing support is a key component connecting the upper and lower vehicles. It not only supports the upper vehicle to rotate relative to the lower vehicle, but also plays the role of transmitting all the forces and torques from the upper part to the lower vehicle structure. Therefore, all torques, including those around the Y axis, will be transmitted to the frame through this path.

[0037] Step S2: Take the rotation center of the truck crane to be analyzed as the coordinate origin, the direction from the coordinate origin to the front of the truck crane as the X-axis direction, and the direction from the coordinate origin to the front of the truck crane as the Y-axis direction. Calculate the torque M of the truck crane to be analyzed rotating around the X-axis based on the following formula: x and the moment M about the X axis y :

[0038] M x =Msinβ,M y =Mcosβ

[0039] Among them, the symbol β represents the working angle of the truck crane to be analyzed, symbol: rad.

[0040] In this step, the moment around the Y axis refers to the effect of the force acting on the truck crane to rotate the crane around the Y axis, and the moment around the X axis refers to the moment acting on the truck crane to rotate the crane around the X axis. It reflects the tendency of the truck crane to rotate around the X axis due to the action of various forces when performing lifting operations. By calculating this moment, it can help determine the overall stability of the truck crane.

[0041] Step S3: Calculate the force F acting on the A leg of the truck crane to be analyzed by the following formula: A , the force F at the B leg B , the force F at the C leg C and the force F acting on the D leg D :

[0042]

[0043] Among them, the symbol G D Indicates the unloading mass of the truck crane to be analyzed, symbol: kg, symbol e b The symbol e represents the truck crane to be analyzed. h represents the truck crane to be analyzed, symbol a1 represents the extended length of the A leg of the truck crane to be analyzed, symbol a2 represents the extended length of the B leg of the truck crane to be analyzed, symbol a3 represents the extended length of the C leg of the truck crane to be analyzed, symbol a4 represents the extended length of the D leg of the truck crane to be analyzed, and symbol b represents the longitudinal span of the legs of the truck crane to be analyzed.

[0044] Step S4: Calculate the absolute value F of the pressure difference between the outriggers A and C of the truck crane to be analyzed by the following formula: AC , and the absolute value F of the pressure difference between leg B and leg D BD :

[0045]

[0046] Get the absolute value F AC and the absolute value F BD The maximum value S min , maximum value S min is the critical pressure difference of the truck crane to be analyzed in a stable working state under theoretical conditions;

[0047] S min =max(F AC ,F BD ).

[0048] This step takes into account that in a confined space, when the outriggers of the truck crane are not fully extended, the pressure of the outriggers close to the boom side (heavy load side) will increase, while the pressure of the outriggers away from the boom side (light load side) will decrease. In this case, the pressure difference between the outriggers on the diagonal line is the largest, because they are located at the most unbalanced positions of the crane, one outrigger is under greater pressure, and the other outrigger is under less pressure or even no pressure. Therefore, the outrigger pressure difference on the diagonal line is selected as the evaluation parameter to more accurately reflect the stability state of the entire truck crane.

[0049] Step S5: Use the pressure sensor to detect the pressure values ​​of the four outriggers of the truck crane to be analyzed in real time, and calculate the absolute value S1 of the pressure difference between outrigger A and outrigger C, and the absolute value S2 of the pressure difference between outrigger B and outrigger D, and take the maximum value S=max(S1, S2); S represents the maximum value of the pressure difference of the two outriggers in the diagonal position of the truck crane to be analyzed under the actual working state; when the value of the maximum value S is greater than the maximum value Smin Or when the pressure on any leg is zero, the truck crane to be analyzed will issue a warning to stop operating.

[0050] In this step, the maximum value S of the pressure difference between the two legs at the diagonal position in the actual working state and the critical pressure difference S in the theoretical state are calculated. min The comparison is to determine whether the truck crane is in a safe working condition. min Or when the pressure on any leg is zero, it means that the truck crane may be close to or reach a critical state of instability. At the same time, if the pressure on a leg is reduced to zero, it means that the leg no longer provides support, and the entire crane relies on other legs to maintain balance, which greatly increases the risk of overturning. At this time, issuing a stop operation warning can effectively prevent potential accidents and ensure operational safety.

[0051] In the technical solution of this application, considering that the outriggers of a truck crane operating in a confined space cannot be fully extended, resulting in a reduction in its support area, the technical solution of this application provides a criterion for judging whether the truck crane will become unstable when operating in a confined space. In the technical solution of this application, by real-time monitoring of the pressure difference between the two outriggers on the diagonal line of the truck crane, uneven pressure distribution can be detected in time, thereby judging whether the crane is in a stable state. If the pressure of a certain outrigger drops to zero or the pressure difference exceeds the preset safety threshold S min , it means that the crane may be close to an unstable state. At this time, it is necessary to activate the alarm mechanism or stop the operation to prevent accidents.

[0052] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for judging the stability of a truck crane, characterized in that: The method comprises: S1. Calculate the concentrated force P and moment M acting on the frame rotation center of the truck crane to be analyzed by the following formula; wherein the truck crane to be analyzed has four legs, marked as A, B, C and D respectively; wherein legs A and C are in a diagonal direction, and legs B and D are in another diagonal direction, and the truck crane to be analyzed operates in a confined space; P=G B +G c +G P +Q M=QR+G c L c +P W L b sinα-G P L P Among them, the symbol G B Indicates the mass of the truck crane to be analyzed, symbol: kg, symbol G c Indicates the boom mass of the truck crane to be analyzed, unit: kg; symbol G P = represents the counterweight mass of the truck crane to be analyzed, unit: kg; symbol Q represents the lifting weight of the truck crane to be analyzed, symbol: kg; symbol R represents the working range of the truck crane to be analyzed, unit: m; symbol L c P represents the distance between the center of mass of the boom of the truck crane to be analyzed and the slewing axis, unit: m; symbol: W It represents the wind load on the truck crane to be analyzed, symbol L b Indicates the boom length of the truck crane to be analyzed, length: m; symbol G P Indicates the counterweight mass of the truck crane to be analyzed, symbol: kg; symbol L P represents the distance between the center of mass of the counterweight of the truck crane to be analyzed and the slewing axis, unit: m; symbol α represents the slewing angle of the truck crane to be analyzed, symbol: rad; S2. Take the rotation center of the truck crane to be analyzed as the coordinate origin, the direction from the coordinate origin to the front of the truck crane as the X-axis direction, and the direction from the coordinate origin to the front of the truck crane as the Y-axis direction. Calculate the torque M of the truck crane to be analyzed rotating around the X-axis based on the following formula: x and the moment M about the X axis y : M x =Msinβ,M y =Mcosβ Wherein, the symbol β represents the working angle of the truck crane to be analyzed, symbol: rad; S3. Calculate the force F acting on the A leg of the truck crane to be analyzed by the following formula: A , the force F at the B leg B , the force F at the C leg C and the force F acting on the D leg D : Among them, the symbol G D Indicates the unloading mass of the truck crane to be analyzed, symbol: kg, symbol e b The symbol e represents the truck crane to be analyzed. h represents the truck crane to be analyzed, symbol a1 represents the extended length of the A outrigger of the truck crane to be analyzed, symbol a2 represents the extended length of the B outrigger of the truck crane to be analyzed, symbol a3 represents the extended length of the C outrigger of the truck crane to be analyzed, symbol a4 represents the extended length of the D outrigger of the truck crane to be analyzed, and symbol b represents the longitudinal span of the outriggers of the truck crane to be analyzed; S4. Calculate the absolute value F of the pressure difference between the outriggers A and C of the truck crane to be analyzed by the following formula: AC , and the absolute value F of the pressure difference between leg B and leg D BD : Get the absolute value F AC and the absolute value F BD The maximum value S min , the maximum value S min is the critical pressure difference of the truck crane to be analyzed in a stable working state under a theoretical state; S min =max(F AC ,F BD ) S5. Use a pressure sensor to detect the pressure values ​​of the four outriggers of the truck crane to be analyzed in real time, and calculate the absolute value S1 of the pressure difference between outrigger A and outrigger C, and the absolute value S2 of the pressure difference between outrigger B and outrigger D, and take the maximum value S=max(S1, S2); S represents the maximum value of the pressure difference of the two outriggers in the diagonal position of the truck crane to be analyzed in the actual working state; when the value of the maximum value S is greater than the maximum value S min Or when the pressure on any leg is zero, a warning to stop operation is issued to the truck crane to be analyzed.

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