Arm length measuring method and arm length measuring device applied to crane

Abstract

The invention relates to the technical field of engineering machinery data processing, in particular to an arm length measuring method and an arm length measuring device applied to a crane. The method comprises the following steps: acquiring scanning point cloud data obtained by scanning in a preset scanning range by a scanning device; a scanning object of the scanning device in a preset scanning range at least comprises a reflection device; the current oil cylinder length of a variable-amplitude oil cylinder of the crane is obtained, the scanning point cloud data are filtered and screened according to the current oil cylinder length, and reflection point cloud data are obtained; the reflection point cloud data is point cloud data obtained by scanning a reflection device by a scanning device; and calculating the current length of the crane jib according to the reflection point cloud data to obtain the measured length of the crane jib. The length of the crane jib is measured through the scanning device, a length measuring cable and a slip ring do not need to be used, and therefore the situation that in the measuring process, due to mechanical abrasion and mechanical fatigue of devices, the measuring accuracy is reduced is avoided, and the measuring accuracy of the crane jib length can be effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of construction machinery data processing, and particularly relates to an arm length measurement method and an arm length measurement device applied to a crane. Background Art

[0002] During the working process of a crane, it is necessary to measure the arm length of the boom in real time to calculate the working radius of the boom, and further calculate the torque value of the load to monitor the working state of the boom. If the load torque value exceeds the data specified by the performance, it means that the boom is in an overloaded working state and an alarm needs to be sent to the staff. Currently, the arm length of the boom is usually measured in real time by a length sensor. Specifically, the length sensor converts the telescopic change of the boom into an electrical signal through a high-strength length measurement cable and a built-in multi-channel slip ring, and then calculates the arm length of the boom according to the collected electrical signal.

[0003] However, it is found in practice that during the use of the length sensor, the measurement accuracy of the sensor for the arm length of the boom is prone to decrease due to factors such as mechanical wear and fatigue, making it difficult to accurately calculate the actual load torque value to monitor the working state of the boom.

[0004] Therefore, how to improve the measurement accuracy of the arm length of the crane boom and thus improve the calculation accuracy of the load torque value is a technical problem that needs to be solved urgently at present. Summary of the Invention

[0005] The present invention provides an arm length measurement method and an arm length measurement device applied to a crane, which can improve the measurement accuracy of the arm length of the crane boom and thus improve the calculation accuracy of the load torque value.

[0006] To solve the above technical problems, in a first aspect of the present invention, an arm length measurement method applied to a crane is disclosed. A scanning device is provided at the connection position between the lifting boom of the crane and the slewing platform, and a reflecting device is provided at the boom tip of the lifting boom. The method includes:

[0007] Obtaining the scanned point cloud data obtained by the scanning device scanning within a preset scanning range; the scanning object of the scanning device within the preset scanning range at least includes the reflecting device;

[0008] Obtaining the current cylinder length of the luffing cylinder of the crane, and filtering and screening the scanned point cloud data according to the current cylinder length to obtain reflected point cloud data; the reflected point cloud data is the point cloud data obtained by the scanning device scanning the reflecting device;

[0009] Calculating the current length of the lifting boom according to the reflected point cloud data to obtain the measured boom length.

[0010] As an alternative implementation, in the first aspect of the present invention, the preset scanning range corresponds to multiple preset scanning angles, and the preset scanning angle is the included angle between the scanning direction of the scanning device and the horizontal plane;

[0011] The obtaining of the scanned point cloud data obtained by the scanning device scanning within the preset scanning range includes:

[0012] For each of the preset scanning angles, obtaining the scanned point data obtained by the scanning device scanning the scanned points corresponding to the preset scanning angle;

[0013] Integrating the scanned point data corresponding to all the preset scanning angles to obtain the scanned point cloud data;

[0014] Among them, for each of the scanned point data, the scanned point data includes the first coordinate value projected on the first coordinate direction, the second coordinate value projected on the second coordinate direction, and the third coordinate value projected on the third coordinate direction of the corresponding scanned point;

[0015] The first coordinate direction is the direction perpendicular to the horizontal plane with the position where the scanning device is located as the origin, the second coordinate direction is the direction parallel to the horizontal plane with the position where the scanning device is located as the origin, and the third coordinate direction is the direction perpendicular to the plane formed by the first coordinate direction and the second coordinate direction with the position where the scanning device is located as the origin.

[0016] As an alternative implementation, in the first aspect of the present invention, the reflection device includes a reflector;

[0017] The obtaining of the current cylinder length of the luffing cylinder of the crane and filtering and screening the scanned point cloud data according to the current cylinder length to obtain the reflected point cloud data includes:

[0018] Obtaining the current cylinder length of the luffing cylinder of the crane, and calculating the included angle between the lifting boom and the slewing platform according to the current cylinder length to obtain the boom lifting angle;

[0019] Calculating the scanning filtering angle according to the pre-stored basic boom length and the reflector length; the basic boom length is the length of the lifting boom when it is not extended, and the reflector length is the length of the reflector in the vertical direction;

[0020] Filtering the scanned point cloud data according to the boom lifting angle and the scanning filtering angle to obtain the filtered point cloud data;

[0021] Screening the filtered point cloud data according to the basic boom length to obtain the reflected point cloud data.

[0022] As an alternative embodiment, in the first aspect of the present invention, the crane is provided with a first connection point, a second connection point and a third connection point. The first connection point is the connection point between the lifting boom and the slewing platform of the crane. The second connection point is the connection point between the luffing cylinder of the crane and the slewing platform. The third connection point is the connection point between the lifting boom and the luffing cylinder of the crane;

[0023] The step of obtaining the current cylinder length of the luffing cylinder of the crane and calculating the included angle between the lifting boom and the slewing platform according to the current cylinder length to obtain the boom lifting angle includes:

[0024] Obtaining the current cylinder length of the luffing cylinder of the crane;

[0025] Calculating the square difference between the pre-stored first connection distance and the current cylinder length to obtain a first calculated value; the first connection distance is the distance between the first connection point and the second connection point;

[0026] Calculating the sum of the square value of the pre-stored second connection distance and the first calculated value to obtain a second calculated value; the second connection distance is the distance between the first connection point and the third connection point;

[0027] Calculating the product of the first connection distance and the second connection distance, and multiplying the obtained product value by two to obtain a third calculated value;

[0028] Calculating the quotient of the second calculated value divided by the third calculated value to obtain a fourth calculated value;

[0029] Performing an inverse cosine operation according to the fourth calculated value to obtain the boom lifting angle.

[0030] As an alternative embodiment, in the first aspect of the present invention, the step of calculating the scanning filter angle according to the pre-stored basic boom length and reflector length includes:

[0031] Calculating the square difference between the basic boom length and the reflector length to obtain a fifth calculated value;

[0032] Performing a square root operation on the fifth calculated value to obtain a sixth calculated value;

[0033] Calculating the quotient of the sixth calculated value divided by the basic boom length to obtain a seventh calculated value;

[0034] Performing an inverse cosine operation according to the seventh calculated value to obtain the scanning filter angle.

[0035] As an alternative implementation, in the first aspect of the present invention, filtering the scanned point cloud data according to the boom lifting angle and the scanning filtering angle to obtain filtered point cloud data includes:

[0036] Calculating the difference between the boom lifting angle and the scanning filtering angle to obtain a first filtering angle;

[0037] Calculating the sum of the boom lifting angle and the scanning filtering angle to obtain a second filtering angle;

[0038] Filtering the scanned point cloud data according to the first filtering angle and the second filtering angle to obtain filtered point cloud data;

[0039] Wherein, for each scanned point data in the filtered point cloud data, the preset scanning angle corresponding to the scanned point data is not less than the first filtering angle and not greater than the second filtering angle.

[0040] As an alternative implementation, in the first aspect of the present invention, screening the filtered point cloud data according to the basic length of the boom to obtain reflected point cloud data includes:

[0041] For each scanned point corresponding to the scanned point data in the filtered point cloud data, calculating the sum of the squares of the first coordinate value and the second coordinate value of the scanned point to obtain an eighth calculated value, and performing a square root operation on the eighth calculated value to obtain the scanning reflection distance of the scanned point; the scanning reflection distance is the distance between the scanned point and the scanning device;

[0042] Screening all the scanned point data in the filtered point cloud data according to the basic length of the boom to obtain reflected point cloud data;

[0043] Wherein, for each scanned point corresponding to the scanned point data in the reflected point cloud data, the scanning reflection distance of the scanned point is greater than the basic length of the boom.

[0044] As an alternative implementation, in the first aspect of the present invention, calculating the current length of the lifting boom according to the reflected point cloud data to obtain the boom measurement length includes:

[0045] For each scanned point corresponding to the scanned point data in the reflected point cloud data, projecting the scanned point onto a vertical projection plane to obtain a vertical projection point corresponding to the scanned point; the vertical projection plane is a plane formed by the first coordinate direction and the third coordinate direction;

[0046] For each of the vertical projection points, determine the nearest neighbor projection point corresponding to the vertical projection point, and calculate the distance between the vertical projection point and its corresponding nearest neighbor projection point to obtain the nearest neighbor point spacing corresponding to the vertical projection point; the nearest neighbor projection point is another vertical projection point with the shortest distance from the vertical projection point;

[0047] Perform statistical analysis on the nearest neighbor point spacings corresponding to all the vertical projection points to obtain a statistical analysis result; the statistical analysis result includes at least a distance anomaly analysis result;

[0048] Screen all the vertical projection points according to the statistical analysis result to obtain a set of target projection points;

[0049] Calculate the first coordinate value of the reflection center point and the third coordinate value of the reflection center point according to all the vertical projection points in the set of target projection points; the reflection center point is the center point of the reflection device;

[0050] Determine the second coordinate value of the reflection center point according to the first coordinate value of the reflection center point and the third coordinate value of the reflection center point;

[0051] Calculate the sum of the squares of the first coordinate value of the reflection center point and the second coordinate value of the reflection center point to obtain a ninth calculated value;

[0052] Perform a square root operation on the ninth calculated value to obtain the boom measurement length.

[0053] A second aspect of the present invention discloses an arm length measuring device applied to a crane. A scanning device is provided at the connection position between the lifting boom of the crane and the slewing platform, and a reflection device is provided at the boom tip of the lifting boom. The device includes:

[0054] A scanning data acquisition device for acquiring scanned point cloud data obtained by the scanning device scanning within a preset scanning range; the scanning object of the scanning device within the preset scanning range includes at least the reflection device;

[0055] A data filtering and screening device for acquiring the current cylinder length of the luffing cylinder of the crane and filtering and screening the scanned point cloud data according to the current cylinder length to obtain reflected point cloud data; the reflected point cloud data is the point cloud data obtained by the scanning device scanning the reflection device;

[0056] A boom length calculation device for calculating the current length of the lifting boom according to the reflected point cloud data to obtain the boom measurement length.

[0057] As an alternative implementation, in the second aspect of the present invention, the preset scanning range corresponds to multiple preset scanning angles, and the preset scanning angle is the included angle between the scanning direction of the scanning device and the horizontal plane;

[0058] The specific manner in which the scanning data acquisition device acquires the scanned point cloud data obtained by the scanning device scanning within the preset scanning range includes:

[0059] For each of the preset scanning angles, acquire the scanned point data obtained by the scanning device scanning the scanned points corresponding to the preset scanning angle;

[0060] Integrate the scanned point data corresponding to all the preset scanning angles to obtain the scanned point cloud data;

[0061] Wherein, for each of the scanned point data, the scanned point data includes the first coordinate value projected on the first coordinate direction, the second coordinate value projected on the second coordinate direction, and the third coordinate value projected on the third coordinate direction corresponding to the scanned point;

[0062] The first coordinate direction is the direction perpendicular to the horizontal plane with the position of the scanning device as the origin, the second coordinate direction is the direction parallel to the horizontal plane with the position of the scanning device as the origin, and the third coordinate direction is the direction perpendicular to the plane formed by the first coordinate direction and the second coordinate direction with the position of the scanning device as the origin.

[0063] As an alternative implementation, in the second aspect of the present invention, the reflection device includes a reflector;

[0064] The specific manner in which the data filtering and screening device acquires the current cylinder length of the luffing cylinder of the crane and filters and screens the scanned point cloud data according to the current cylinder length to obtain the reflected point cloud data includes:

[0065] Acquire the current cylinder length of the luffing cylinder of the crane, and calculate the included angle between the lifting boom and the slewing platform according to the current cylinder length to obtain the boom lifting angle;

[0066] Calculate the scanning filtering angle according to the pre-stored basic boom length and the reflector length; the basic boom length is the length of the lifting boom when it is not extended, and the reflector length is the length of the reflector in the vertical direction;

[0067] Filter the scanned point cloud data according to the boom lifting angle and the scanning filtering angle to obtain the filtered point cloud data;

[0068] Filter the filtered point cloud data according to the basic length of the boom to obtain the reflected point cloud data.

[0069] As an alternative implementation, in the second aspect of the present invention, the crane is provided with a first connection point, a second connection point, and a third connection point. The first connection point is the connection point between the lifting boom and the slewing platform of the crane. The second connection point is the connection point between the luffing cylinder of the crane and the slewing platform of the crane. The third connection point is the connection point between the lifting boom and the luffing cylinder of the crane.

[0070] The data filtering and screening device obtains the current cylinder length of the luffing cylinder of the crane, and calculates the angle between the lifting boom and the slewing platform according to the current cylinder length to obtain the specific method of the boom lifting angle, including:

[0071] Obtain the current cylinder length of the luffing cylinder of the crane;

[0072] Calculate the square difference between the pre-stored first connection distance and the current cylinder length to obtain a first calculated value; the first connection distance is the distance between the first connection point and the second connection point;

[0073] Calculate the sum value of the square value of the pre-stored second connection distance and the first calculated value to obtain a second calculated value; the second connection distance is the distance between the first connection point and the third connection point;

[0074] Calculate the product of the first connection distance and the second connection distance, and multiply the obtained product value by two to obtain a third calculated value;

[0075] Calculate the quotient of the second calculated value divided by the third calculated value to obtain a fourth calculated value;

[0076] Perform an inverse cosine operation according to the fourth calculated value to obtain the boom lifting angle.

[0077] As an alternative implementation, in the second aspect of the present invention, the specific method for the data filtering and screening device to calculate the scanning and filtering angle according to the pre-stored basic length of the boom and the length of the reflector includes:

[0078] Calculate the square difference between the basic length of the boom and the length of the reflector to obtain a fifth calculated value;

[0079] Perform a square root operation on the fifth calculated value to obtain a sixth calculated value;

[0080] Calculate the quotient of the sixth calculated value divided by the basic length of the boom to obtain a seventh calculated value;

[0081] Perform an arccosine operation based on the seventh calculated value to obtain the scanning filtering angle.

[0082] As an alternative implementation, in the second aspect of the present invention, the specific manner in which the data filtering and screening device filters the scanned point cloud data according to the boom lifting angle and the scanning filtering angle to obtain filtered point cloud data includes:

[0083] Calculate the difference between the boom lifting angle and the scanning filtering angle to obtain a first filtering angle;

[0084] Calculate the sum of the boom lifting angle and the scanning filtering angle to obtain a second filtering angle;

[0085] Filter the scanned point cloud data according to the first filtering angle and the second filtering angle to obtain filtered point cloud data;

[0086] Among them, for each scanned point data in the filtered point cloud data, the preset scanning angle corresponding to this scanned point data is not less than the first filtering angle and not greater than the second filtering angle.

[0087] As an alternative implementation, in the second aspect of the present invention, the specific manner in which the data filtering and screening device screens the filtered point cloud data according to the basic length of the boom to obtain reflected point cloud data includes:

[0088] For each scanned point corresponding to the scanned point data in the filtered point cloud data, calculate the sum of the squares of the first coordinate value and the second coordinate value of this scanned point to obtain an eighth calculated value, and perform a square root operation on the eighth calculated value to obtain the scanning reflection distance of this scanned point; the scanning reflection distance is the distance between this scanned point and the scanning device;

[0089] Screen all the scanned point data in the filtered point cloud data according to the basic length of the boom to obtain reflected point cloud data;

[0090] Among them, for each scanned point corresponding to the scanned point data in the reflected point cloud data, the scanning reflection distance of this scanned point is greater than the basic length of the boom.

[0091] As an alternative implementation, in the second aspect of the present invention, the specific manner in which the boom length calculation device calculates the current length of the lifting boom according to the reflected point cloud data to obtain the measured boom length includes:

[0092] For each scanned point corresponding to the scanned point data in the reflected point cloud data, project this scanned point onto the vertical projection plane to obtain the vertical projection point corresponding to this scanned point; the vertical projection plane is the plane formed by the first coordinate direction and the third coordinate direction;

[0093] For each of the vertical projection points, determine the nearest neighbor projection point corresponding to the vertical projection point, and calculate the distance between the vertical projection point and its corresponding nearest neighbor projection point to obtain the nearest neighbor point spacing corresponding to the vertical projection point; the nearest neighbor projection point is another vertical projection point with the shortest distance from the vertical projection point.

[0094] Perform statistical analysis on the nearest neighbor point spacings corresponding to all the vertical projection points to obtain a statistical analysis result; the statistical analysis result includes at least a distance anomaly analysis result.

[0095] Screen all the vertical projection points according to the statistical analysis result to obtain a set of target projection points.

[0096] Calculate the first coordinate value of the reflection center point and the third coordinate value of the reflection center point according to all the vertical projection points in the set of target projection points; the reflection center point is the center point of the reflection device.

[0097] Determine the second coordinate value of the reflection center point according to the first coordinate value of the reflection center point and the third coordinate value of the reflection center point.

[0098] Calculate the sum of the squares of the first coordinate value of the reflection center point and the second coordinate value of the reflection center point to obtain a ninth calculated value.

[0099] Perform a square root operation on the ninth calculated value to obtain the boom measurement length.

[0100] The third aspect of the present invention discloses another boom length measuring device applied to a crane, and the device includes:

[0101] A memory storing executable program code;

[0102] A processor coupled to the memory;

[0103] The processor calls the executable program code stored in the memory and executes a boom length measuring method applied to a crane disclosed in the first aspect of the present invention.

[0104] The fourth aspect of the present invention discloses a computer storage medium, and the computer storage medium stores computer instructions, which are used to execute a boom length measuring method applied to a crane disclosed in the first aspect of the present invention when called by a processor.

[0105] Compared with the prior art, the present invention has the following beneficial effects:

[0106] First, obtain the scanned point cloud data obtained by the scanning device during scanning within a preset scanning range; then, obtain the current cylinder length of the luffing cylinder of the crane, and filter and screen the scanned point cloud data according to the current cylinder length to remove interference data and retain the reflected point cloud data obtained by the scanning and reflecting device; finally, calculate the current length of the lifting boom according to the reflected point cloud data to obtain the measured boom length. Measuring the length of the crane boom by the scanning device eliminates the need to use measuring wire ropes and slip rings, thus avoiding the decrease in measurement accuracy caused by mechanical wear and mechanical fatigue of components during the measurement process, effectively improving the measurement accuracy of the crane boom length, and further improving the calculation accuracy of the load torque value and the monitoring reliability of the boom working state. BRIEF DESCRIPTION OF THE DRAWINGS

[0107] To more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0108] Figure 1 is a schematic flowchart of a method for measuring the boom length of a crane applied in an embodiment of the present invention;

[0109] Figure 2 is a schematic diagram of the scanning range of the scanning device in an embodiment of the present invention;

[0110] Figure 3 is a schematic structural diagram of a device for measuring the boom length of a crane applied in an embodiment of the present invention;

[0111] Figure 4 is a schematic structural diagram of another device for measuring the boom length of a crane applied in an embodiment of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0112] To enable those skilled in the art to better understand the solutions of the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0113] The terms "first", "second", etc. in the specification and claims of the present invention and the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order. In addition, the terms "including" and "having" and any variations thereof are intended to cover non-exclusive inclusions. For example, a process, method, device, product that includes a series of steps or units or is not limited to the listed steps or units, but optionally includes steps or units that are not listed, or optionally includes other steps or units inherent to these processes, methods, products, or other steps or units.

[0114] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0115] During the operation of the crane, it is necessary to measure the arm length of the boom in real time to calculate the working range of the boom, and then further calculate the load torque value to monitor the working status of the boom. If the load torque value exceeds the performance data, it means that the boom is in an overloaded working state, and an alarm needs to be sent to the staff. At present, the arm length of the boom is usually measured in real time through a length sensor. Specifically, the length sensor converts the telescopic changes of the boom into electrical signals through high-strength length measurement cables and built-in multi-way slip rings, and then calculates the arm length of the boom based on the collected electrical signals.

[0116] However, practice has found that the length sensor is prone to mechanical wear, fatigue and other factors during use, which may cause the sensor's measurement accuracy of the boom length to decrease, making it difficult to accurately calculate the actual load torque value to monitor the working status of the boom.

[0117] Therefore, how to improve the measurement accuracy of the crane boom length, thereby improving the calculation accuracy of the load moment value, is a technical problem that needs to be solved urgently.

[0118] In order to solve the above technical problems, the present invention discloses a boom length measurement method and boom length measurement device applied to a crane, aiming to improve the measurement accuracy of the boom length of the crane, thereby improving the calculation accuracy of the load moment value. Detailed descriptions are given below.

[0119] Embodiment 1

[0120] See also Figure 1 , Figure 1 1 is a flow chart of a method for measuring arm length of a crane disclosed in an embodiment of the present invention. Figure 1The method shown can be implemented in an arm length measuring device applied to a crane. When the arm length measuring device executes an arm length measuring method for a crane disclosed in an embodiment of the present invention, it can improve the measuring accuracy of the boom length of the crane. A scanning device is provided at the connection position between the lifting boom of the crane and the slewing platform, and a reflecting device is provided at the boom tip of the lifting boom, such as Figure 1 As shown, an arm length measuring method for a crane disclosed in an embodiment of the present invention includes but is not limited to the following operations:

[0121] 101. Obtain the scanned point cloud data obtained by the scanning device scanning within a preset scanning range; the scanning object of the scanning device within the preset scanning range at least includes the reflecting device.

[0122] 102. Obtain the current cylinder length of the luffing cylinder of the crane, and filter and screen the scanned point cloud data according to the current cylinder length to obtain the reflected point cloud data; the reflected point cloud data is the point cloud data obtained by the scanning device scanning the reflecting device.

[0123] 103. Calculate the current length of the lifting boom according to the reflected point cloud data to obtain the boom measurement length.

[0124] First, obtain the scanned point cloud data obtained by the scanning device scanning within a preset scanning range; then obtain the current cylinder length of the luffing cylinder of the crane, filter and screen the scanned point cloud data according to the current cylinder length, remove the interference data, and retain the reflected point cloud data obtained by scanning the reflecting device; finally, calculate the current length of the lifting boom according to the reflected point cloud data to obtain the boom measurement length.

[0125] It can be seen that in the embodiment of the present invention, by using the scanning device to measure the length of the crane boom, there is no need to use measuring long cables and slip rings, thereby avoiding the situation that the measuring accuracy decreases due to mechanical wear and device mechanical fatigue during the measurement process, and can effectively improve the measuring accuracy of the crane boom length, and further improve the calculation accuracy of the load torque value and the monitoring reliability of the boom working state.

[0126] In an alternative embodiment, the scanning device employs a phase-type laser scanner, whose scanning frequency is set from 100 Hz to 500 Hz, and the scanning angular resolution is from 0.01 degrees to 0.1 degrees. The phase-type laser scanner calculates the distance between the scanning point and the scanning device based on the phase difference by emitting a modulated laser beam and receiving the reflected signal. The working wavelength of this scanner is 905 nm, the maximum ranging distance is 200 meters, and the ranging accuracy is ±1 mm. By optimizing the scanning frequency and resolution, it is possible to quickly generate high-density scanned point cloud data within the preset scanning range while ensuring the accurate identification of the reflecting device. In addition, the scanning device is equipped with a dustproof and waterproof housing with an IP67 protection level, suitable for the complex operating environment of construction machinery. The scanning device communicates with the control system of the crane via CAN bus or Ethernet, and transmits the scanned point cloud data to the data processing unit in real time to ensure the real-time performance and reliability of the measurement process.

[0127] In another alternative embodiment, the preset scanning range corresponds to multiple preset scanning angles, and the preset scanning angle is the included angle between the scanning direction of the scanning device and the horizontal plane;

[0128] Obtaining the scanned point cloud data obtained by the scanning device scanning within the preset scanning range specifically includes:

[0129] For each preset scanning angle, obtain the scanned point data obtained by the scanning device scanning the scanned points corresponding to this preset scanning angle;

[0130] Integrate the scanned point data corresponding to all preset scanning angles to obtain the scanned point cloud data;

[0131] Among them, for each scanned point data, this scanned point data includes the first coordinate value projected on the first coordinate direction, the second coordinate value projected on the second coordinate direction, and the third coordinate value projected on the third coordinate direction of its corresponding scanned point;

[0132] The first coordinate direction is the direction perpendicular to the horizontal plane with the position of the scanning device as the origin, the second coordinate direction is the direction parallel to the horizontal plane with the position of the scanning device as the origin, and the third coordinate direction is the direction perpendicular to the plane formed by the first coordinate direction and the second coordinate direction with the position of the scanning device as the origin.

[0133] Please refer to Figure 2 , Figure 2 which is a schematic diagram of the scanning range of the scanning device in an embodiment of the present invention. As Figure 2 shown, x represents the first coordinate direction, y represents the second coordinate direction, and z represents the third coordinate direction.

[0134] The angular range of the preset scanning angle can be set from 0 to 90 degrees. Each scanning point data includes, in addition to the coordinate value of its corresponding scanning point, the corresponding scanning angle and the reflectivity of the scanning point. Further, the data structure of the scanned point cloud data is as follows:

[0135] First coordinate value Second coordinate value Third coordinate value Preset scanning angle Reflectivity Scanning point data 1 x1 y1 z1 β1 r1 Scanning point data 2 x2 y2 z2 β2 r2 … … … … … … Scanning point data n xn yn zn βn rn

[0136] In another alternative embodiment, the reflecting device includes a reflector;

[0137] Obtaining the current cylinder length of the luffing cylinder of the crane and filtering and screening the scanned point cloud data according to the current cylinder length to obtain the reflected point cloud data specifically includes:

[0138] Obtaining the current cylinder length of the luffing cylinder of the crane and calculating the included angle between the lifting boom and the slewing platform according to the current cylinder length to obtain the boom lifting angle;

[0139] Calculating the scanning filtering angle according to the pre-stored basic boom length and the reflector length; the basic boom length is the length of the lifting boom when it is not extended, and the reflector length is the length of the reflector in the vertical direction;

[0140] Filtering the scanned point cloud data according to the boom lifting angle and the scanning filtering angle to obtain the filtered point cloud data;

[0141] Screening the filtered point cloud data according to the basic boom length to obtain the reflected point cloud data.

[0142] It can be seen that in this alternative embodiment, the scanned point cloud data is filtered and screened according to the current cylinder length and the reflector length, the interference data is removed, the data calculation amount is reduced, and the reflected point cloud data obtained by the scanning reflection device is retained, so as to calculate the boom length of the crane according to the reflected power data.

[0143] In another alternative embodiment, the reflecting device is a prism structure, made of a high-reflectivity glass material, with a metal reflective film plated on the surface, and the reflectivity is greater than 90%. The reflector is installed along the vertical direction of the boom head of the lifting boom, and its center point is aligned with the telescopic axis of the boom. Fixing brackets are provided around the reflector, the brackets are made of lightweight aluminum alloy material, and are rigidly connected to the boom head through bolts. To further enhance the anti-interference ability, the surface of the reflector is covered with a polarization filter, which can effectively suppress the interference of stray light in the ambient light on the scanning signal. The installation angle of the reflector is adjustable, and by adjusting the bolts, its normal direction is aligned with the preset scanning direction of the scanning device, so as to maximize the reflected signal intensity and improve the signal-to-noise ratio of the point cloud data.

[0144] In another alternative embodiment, the crane is provided with a first connection point, a second connection point and a third connection point. The first connection point is the connection point between the lifting boom and the slewing platform of the crane. The second connection point is the connection point between the luffing cylinder of the crane and the slewing platform. The third connection point is the connection point between the lifting boom and the luffing cylinder of the crane;

[0145] Obtaining the current cylinder length of the luffing cylinder of the crane and calculating the angle between the lifting boom and the slewing platform according to the current cylinder length to obtain the boom lifting angle specifically includes:

[0146] Obtaining the current cylinder length of the luffing cylinder of the crane;

[0147] Calculating the square difference between the pre-stored first connection distance and the current cylinder length to obtain a first calculated value; the first connection distance is the distance between the first connection point and the second connection point;

[0148] Calculating the sum of the square value of the pre-stored second connection distance and the first calculated value to obtain a second calculated value; the second connection distance is the distance between the first connection point and the third connection point;

[0149] Calculating the product of the first connection distance and the second connection distance, and multiplying the obtained product value by two to obtain a third calculated value;

[0150] Calculating the quotient of the second calculated value divided by the third calculated value to obtain a fourth calculated value;

[0151] Performing an inverse cosine operation according to the fourth calculated value to obtain the boom lifting angle.

[0152] In this alternative embodiment, the calculation formula for the boom lifting angle is:

[0153]

[0154] Wherein, θ represents the boom lifting angle, a represents the first connection distance, b represents the current cylinder length of the luffing cylinder of the crane, and c represents the second connection distance. It can be understood that the first connection distance and the second connection distance are fixed values measured and stored in advance. In an implementation scenario, the first connection distance is 2 meters, the second connection distance is 4 meters, and the current cylinder length of the luffing cylinder of the crane is 3 meters, then the corresponding boom lifting angle is approximately 46.6 degrees.

[0155] In another alternative embodiment, calculating the scanning filter angle according to the pre-stored basic boom length and reflector length specifically includes:

[0156] Calculating the square difference between the basic boom length and the reflector length to obtain a fifth calculated value;

[0157] Performing a square root operation on the fifth calculated value to obtain a sixth calculated value;

[0158] Calculate the quotient of the sixth calculated value divided by the basic length of the boom to obtain the seventh calculated value;

[0159] Perform an arccosine operation based on the seventh calculated value to obtain the scanning filter angle.

[0160] In this optional embodiment, the calculation formula for the scanning filter angle is:

[0161]

[0162] Where γ represents the scanning filter angle, d represents the basic length of the boom, and L represents the length of the reflector. It can be understood that the basic length of the boom and the length of the reflector are fixed values measured and stored in advance. In an implementation scenario, the basic length of the boom is 20 meters, and the reflector is a circular plate with a diameter of 0.5 meters. Then, the corresponding scanning filter angle is calculated to be 1.59 degrees. Through vehicle calibration, the scanning filter angle can be taken as 2 degrees.

[0163] In another optional embodiment, filtering the scanned point cloud data according to the boom lifting angle and the scanning filter angle to obtain the filtered point cloud data specifically includes:

[0164] Calculate the difference between the boom lifting angle and the scanning filter angle to obtain the first filtering angle;

[0165] Calculate the sum of the boom lifting angle and the scanning filter angle to obtain the second filtering angle;

[0166] Filter the scanned point cloud data according to the first filtering angle and the second filtering angle to obtain the filtered point cloud data;

[0167] Among them, for each scanned point data in the filtered point cloud data, the preset scanning angle corresponding to the scanned point data is not less than the first filtering angle and not greater than the second filtering angle.

[0168] It can be seen that in this optional embodiment, the interference data of invalid angles is removed according to the boom lifting angle and the scanning filter angle, and the reflected point cloud data obtained by the scanning reflection device is retained, thereby reducing the data calculation amount and improving the measurement accuracy of the boom.

[0169] In another optional embodiment, screening the filtered point cloud data according to the basic length of the boom to obtain the reflected point cloud data specifically includes:

[0170] For each scanned point corresponding to the scanned point data in the filtered point cloud data, calculate the sum of the squares of the first coordinate value and the second coordinate value of the scanned point to obtain the eighth calculated value, and perform a square root operation on the eighth calculated value to obtain the scanning reflection distance of the scanned point; the scanning reflection distance is the distance between the scanned point and the scanning device;

[0171] Filter all the scanned point data in the filtered point cloud data according to the basic length of the boom to obtain the reflected point cloud data;

[0172] Among them, for each scanned point corresponding to the scanned point data in the reflected point cloud data, the scanned reflection distance of this scanned point is greater than the basic length of the boom.

[0173] It can be seen that this optional embodiment filters the scanned point data with a reflection distance not greater than the basic length of the boom to further remove the interference data with invalid distances, thereby reducing the subsequent data calculation amount and improving the accuracy of boom measurement.

[0174] In another optional embodiment, calculating the current length of the lifting boom according to the reflected point cloud data to obtain the boom measurement length specifically includes:

[0175] For each scanned point corresponding to the scanned point data in the reflected point cloud data, project this scanned point onto the vertical projection plane to obtain the vertical projection point corresponding to this scanned point; the vertical projection plane is the plane formed by the first coordinate direction and the third coordinate direction;

[0176] For each vertical projection point, determine the nearest neighbor projection point corresponding to this vertical projection point, and calculate the distance between this vertical projection point and its corresponding nearest neighbor projection point to obtain the nearest neighbor point spacing corresponding to this vertical projection point; the nearest neighbor projection point is the other vertical projection point with the shortest distance from this vertical projection point;

[0177] Perform statistical analysis on the nearest neighbor point spacings corresponding to all vertical projection points to obtain the statistical analysis result; the statistical analysis result at least includes the distance anomaly analysis result;

[0178] Filter all the vertical projection points according to the statistical analysis result to obtain the target projection point set;

[0179] Calculate the first coordinate value and the third coordinate value of the reflection center point according to all the vertical projection points in the target projection point set; the reflection center point is the center point of the reflection device;

[0180] Determine the second coordinate value of the reflection center point according to the first coordinate value and the third coordinate value of the reflection center point;

[0181] Calculate the sum of the squares of the first coordinate value and the second coordinate value of the reflection center point to obtain the ninth calculated value;

[0182] Perform a square root operation on the ninth calculated value to obtain the boom measurement length.

[0183] In this alternative embodiment, the projections of the scanning points on the same scanning line on the vertical projection plane form a continuous image. Therefore, all the scanning points in the reflected point cloud data are projected onto the vertical projection plane. The distance from each projected point to its nearest neighbor is calculated. For the projected points corresponding to normal scanning points, the spacing between these points is uniform and relatively stable, while the spacing of noise points will deviate significantly from the average value. Statistical analysis is performed on the nearest neighbor spacings of all projected points, such as calculating the mean and standard deviation, and then the points with distances exceeding the mean ± 3 times the standard deviation are selected and removed as abnormal noise points to obtain the set of target projected points. The central point coordinates of all the projected points in the set of target projected points are calculated, which are the projected point coordinates of the reflection center point on the vertical projection plane. Based on this central point coordinate, the second coordinate value of the reflection center point is deduced, and thus the boom measurement length is calculated according to the first coordinate value and the second coordinate value of the reflection center point.

[0184] In another alternative embodiment, the boom length measurement method can also be applied to a multi-section telescopic boom crane. For a crane with multiple nested booms, a reflection device is installed at the end of each boom. The scanning device sequentially scans each reflector through a preset program and calculates the total boom length based on the telescopic amounts of each boom superimposed. The relative displacements of each boom are obtained, and cross-validation is achieved in combination with the scanning data to eliminate the cumulative error caused by mechanical clearance.

[0185] Embodiment 2

[0186] Please refer to Figure 3 , Figure 3 which is a schematic structural diagram of an arm length measurement device applied to a crane disclosed in an embodiment of the present invention. Among them, Figure 3 the device shown is used to implement an arm length measurement method for a crane described in Embodiment 1. When the arm length measurement device executes the arm length measurement method, it can improve the measurement accuracy of the boom length of the crane. A scanning device is provided at the connection position between the lifting boom and the slewing platform of the crane, and a reflection device is provided at the boom tip of the lifting boom. As Figure 3 shown, an arm length measurement device applied to a crane disclosed in an embodiment of the present invention includes but is not limited to the following modules:

[0187] A scanning data acquisition device 201, configured to acquire scanning point cloud data obtained by the scanning device scanning within a preset scanning range; the scanning object of the scanning device within the preset scanning range at least includes the reflection device;

[0188] A data filtering and screening device 202, configured to acquire the current cylinder length of the luffing cylinder of the crane and filter and screen the scanning point cloud data according to the current cylinder length to obtain reflected point cloud data; the reflected point cloud data is the point cloud data obtained by the scanning device scanning the reflection device;

[0189] The boom length calculation device 203 is used to calculate the current length of the lifting boom according to the reflected point cloud data, and obtain the boom measurement length.

[0190] First, obtain the scanned point cloud data obtained by the scanning device scanning within the preset scanning range; then obtain the current cylinder length of the luffing cylinder of the crane, filter and screen the scanned point cloud data according to the current cylinder length, remove the interference data, and retain the reflected point cloud data obtained by the scanning and reflecting device; finally, calculate the current length of the lifting boom according to the reflected point cloud data to obtain the boom measurement length.

[0191] It can be seen that in the embodiment of the present invention, by measuring the length of the crane boom with a scanning device, there is no need to use a measuring wire cable and a slip ring, thus avoiding the situation that the measurement accuracy decreases due to mechanical wear and device mechanical fatigue during the measurement process, and can effectively improve the measurement accuracy of the crane boom length, and further improve the calculation accuracy of the load torque value and the monitoring reliability of the boom working state.

[0192] In an alternative embodiment, the preset scanning range corresponds to multiple preset scanning angles, and the preset scanning angle is the included angle between the scanning direction of the scanning device and the horizontal plane;

[0193] The specific manner in which the scan data acquisition device 201 acquires the scanned point cloud data obtained by the scanning device scanning within the preset scanning range includes:

[0194] For each preset scanning angle, acquire the scanned point data obtained by the scanning device scanning the scanned points corresponding to the preset scanning angle;

[0195] Integrate the scanned point data corresponding to all preset scanning angles to obtain the scanned point cloud data;

[0196] Among them, for each scanned point data, the scanned point data includes the first coordinate value of its corresponding scanned point projected in the first coordinate direction, the second coordinate value projected in the second coordinate direction, and the third coordinate value projected in the third coordinate direction;

[0197] The first coordinate direction is the direction perpendicular to the horizontal plane with the position of the scanning device as the origin, the second coordinate direction is the direction parallel to the horizontal plane with the position of the scanning device as the origin, and the third coordinate direction is the direction perpendicular to the plane formed by the first coordinate direction and the second coordinate direction with the position of the scanning device as the origin.

[0198] Please refer to Figure 2 , Figure 2 is a schematic diagram of the scanning range of the scanning device in an embodiment of the present invention. As Figure 2 shown, x represents the first coordinate direction, y represents the second coordinate direction, and z represents the third coordinate direction.

[0199] The angular range of the preset scanning angle can be set from 0 to 90 degrees. In addition to the coordinate values of its corresponding scanning point, each scanning point data also includes the corresponding scanning angle and the reflectivity of the scanning point.

[0200] In another alternative embodiment, the reflecting device includes a reflector;

[0201] The data filtering and screening device 202 obtains the current cylinder length of the luffing cylinder of the crane, and filters and screens the scanned point cloud data according to the current cylinder length to obtain the reflected point cloud data. The specific methods include:

[0202] Obtain the current cylinder length of the luffing cylinder of the crane, and calculate the included angle between the lifting boom and the slewing platform according to the current cylinder length to obtain the boom lifting angle;

[0203] Calculate the scanning filtering angle according to the pre-stored basic boom length and the reflector length; the basic boom length is the length of the lifting boom when it is not extended, and the reflector length is the length of the reflector in the vertical direction;

[0204] Filter the scanned point cloud data according to the boom lifting angle and the scanning filtering angle to obtain the filtered point cloud data;

[0205] Screen the filtered point cloud data according to the basic boom length to obtain the reflected point cloud data.

[0206] It can be seen that in this alternative embodiment, the scanned point cloud data is filtered and screened according to the current cylinder length and the reflector length, the interference data is removed, the data calculation amount is reduced, and the reflected point cloud data obtained by the scanning and reflecting device is retained, so as to calculate the boom length of the crane boom according to the reflected power supply data.

[0207] In another alternative embodiment, the crane is provided with a first connection point, a second connection point and a third connection point. The first connection point is the connection point between the lifting boom and the slewing platform, the second connection point is the connection point between the luffing cylinder of the crane and the slewing platform, and the third connection point is the connection point between the lifting boom and the luffing cylinder of the crane;

[0208] The data filtering and screening device 202 obtains the current cylinder length of the luffing cylinder of the crane, and calculates the included angle between the lifting boom and the slewing platform according to the current cylinder length to obtain the boom lifting angle. The specific methods include:

[0209] Obtain the current cylinder length of the luffing cylinder of the crane;

[0210] Calculate the square difference between the pre-stored first connection distance and the current cylinder length to obtain a first calculated value; the first connection distance is the distance between the first connection point and the second connection point;

[0211] Calculate the sum value of the square value of the pre-stored second connection distance and the first calculated value to obtain a second calculated value; the second connection distance is the distance between the first connection point and the third connection point.

[0212] Calculate the product of the first connection distance and the second connection distance, and multiply the obtained product value by two to obtain a third calculated value.

[0213] Calculate the quotient of the second calculated value divided by the third calculated value to obtain a fourth calculated value.

[0214] Perform an inverse cosine operation based on the fourth calculated value to obtain the boom jacking angle.

[0215] In this alternative embodiment, the calculation formula for the boom jacking angle is:

[0216]

[0217] Wherein, θ represents the boom jacking angle, a represents the first connection distance, b represents the current cylinder length of the luffing cylinder of the crane, and c represents the second connection distance. It can be understood that the first connection distance and the second connection distance are fixed values measured and stored in advance.

[0218] In an alternative embodiment, the specific manner in which the data filtering and screening device 202 calculates the scanning filter angle based on the pre-stored basic boom length and reflector length includes:

[0219] Calculate the square difference between the basic boom length and the reflector length to obtain a fifth calculated value.

[0220] Perform a square root operation on the fifth calculated value to obtain a sixth calculated value.

[0221] Calculate the quotient of the sixth calculated value divided by the basic boom length to obtain a seventh calculated value.

[0222] Perform an inverse cosine operation based on the seventh calculated value to obtain the scanning filter angle.

[0223] In this alternative embodiment, the calculation formula for the scanning filter angle is:

[0224]

[0225] Wherein, γ represents the scanning filter angle, d represents the basic boom length, and L represents the reflector length. It can be understood that the basic boom length and the reflector length are fixed values measured and stored in advance.

[0226] In another alternative embodiment, the specific manner in which the data filtering and screening device 202 filters the scanned point cloud data based on the boom jacking angle and the scanning filter angle to obtain the filtered point cloud data includes:

[0227] Calculate the difference between the boom jacking angle and the scanning filtering angle to obtain the first filtering angle;

[0228] Calculate the sum of the boom jacking angle and the scanning filtering angle to obtain the second filtering angle;

[0229] Filter the scanned point cloud data according to the first filtering angle and the second filtering angle to obtain the filtered point cloud data;

[0230] Among them, for each scanned point data in the filtered point cloud data, the preset scanning angle corresponding to the scanned point data is not less than the first filtering angle and not greater than the second filtering angle.

[0231] It can be seen that in this optional embodiment, the interference data of invalid angles is removed according to the boom jacking angle and the scanning filtering angle, and the reflected point cloud data obtained by the scanning reflection device is retained, thereby reducing the data calculation amount and improving the boom measurement accuracy.

[0232] In another optional embodiment, the specific manner in which the data filtering and screening device 202 screens the filtered point cloud data according to the basic length of the boom to obtain the reflected point cloud data includes:

[0233] For each scanned point corresponding to the scanned point data in the filtered point cloud data, calculate the sum of the squares of the first coordinate value and the second coordinate value of the scanned point to obtain the eighth calculated value, and perform a square root operation on the eighth calculated value to obtain the scanning reflection distance of the scanned point; the scanning reflection distance is the distance between the scanned point and the scanning device;

[0234] Screen all the scanned point data in the filtered point cloud data according to the basic length of the boom to obtain the reflected point cloud data;

[0235] Among them, for each scanned point corresponding to the scanned point data in the reflected point cloud data, the scanning reflection distance of the scanned point is greater than the basic length of the boom.

[0236] It can be seen that in this optional embodiment, the scanned point data with a reflection distance not greater than the basic length of the boom is filtered to further remove the interference data of invalid distances, thereby reducing the subsequent data calculation amount and improving the boom measurement accuracy.

[0237] In another alternative embodiment, the data filtering and screening device 202 may introduce an adaptive threshold algorithm to dynamically adjust the filtering angle and distance threshold. Specifically, the device establishes an association model between the boom lifting angle and the scanning filtering angle based on historical measurement data, and smooths the current cylinder length data through a Kalman filter to reduce the angle calculation error caused by cylinder jitter. In addition, the device monitors the ambient light intensity and temperature changes in real time. If the light intensity exceeds the preset threshold or the temperature change causes thermal drift of the scanning device, the compensation mechanism is automatically triggered to adjust the scanning parameters or recalibrate the coordinate system. For example, when the ambient temperature change exceeds ±5°C, the system calls the pre-stored temperature minus displacement compensation coefficient to linearly correct the coordinate values in the scanned point cloud data to ensure that the measurement results are not affected by thermal expansion.

[0238] In another alternative embodiment, the boom length calculation device 203 calculates the current length of the lifting boom according to the reflected point cloud data. The specific method for obtaining the measured boom length includes:

[0239] For each scan point corresponding to the scan point data in the reflected point cloud data, project the scan point onto the vertical projection plane to obtain the corresponding vertical projection point of the scan point; the vertical projection plane is the plane formed by the first coordinate direction and the third coordinate direction;

[0240] For each vertical projection point, determine the nearest neighbor projection point corresponding to the vertical projection point, and calculate the distance between the vertical projection point and its corresponding nearest neighbor projection point to obtain the nearest neighbor point spacing corresponding to the vertical projection point; the nearest neighbor projection point is the other vertical projection point with the shortest distance from the vertical projection point;

[0241] Perform statistical analysis on the nearest neighbor point spacings corresponding to all vertical projection points to obtain a statistical analysis result; the statistical analysis result includes at least a distance anomaly analysis result;

[0242] Screen all vertical projection points according to the statistical analysis result to obtain a set of target projection points;

[0243] Calculate the first coordinate value and the third coordinate value of the reflection center point according to all the vertical projection points in the set of target projection points; the reflection center point is the center point of the reflection device;

[0244] Determine the second coordinate value of the reflection center point according to the first coordinate value and the third coordinate value of the reflection center point;

[0245] Calculate the sum of the squares of the first coordinate value and the second coordinate value of the reflection center point to obtain a ninth calculated value;

[0246] Perform a square root operation on the ninth calculated value to obtain the measured boom length.

[0247] In this alternative embodiment, the projections of the scanning points on the same scanning line on the vertical projection plane form a continuous image. Therefore, all the scanning points in the reflected point cloud data are projected onto the vertical projection plane. The distance from each projection point to its nearest neighbor is calculated. For the projection points corresponding to normal scanning points, the spacing between these points is uniform and relatively stable, while the spacing of noise points will deviate significantly from the average value. Statistical analysis is performed on the nearest neighbor spacings of all projection points, such as calculating the mean and standard deviation, and then the points with a distance exceeding the mean ± 3 times the standard deviation are selected as abnormal noise points to be removed, obtaining the set of target projection points. The central point coordinates of all the projection points in the set of target projection points are calculated, which are the coordinates of the projection point of the reflection center point on the vertical projection plane. Based on this central point coordinate, the second coordinate value of the reflection center point is deduced, and thus the boom measurement length is calculated according to the first coordinate value and the second coordinate value of the reflection center point.

[0248] In another alternative embodiment, the boom length calculation device 203 can integrate an outlier rejection module, and analyze the reflected point cloud data using a density clustering algorithm. Specifically, the module first calculates the spatial density of all scanning points, marks the isolated points with a density lower than the threshold as noise and removes them; subsequently, plane fitting is performed on the remaining point cloud, the equation of the plane where the reflector is located is solved using the least squares method, and the edge points of the reflector are extracted according to the plane equation. The edge points detect the line features through the Hough transform, and finally determine the geometric center coordinates of the reflector. This method can effectively eliminate the outlier points introduced by the temporary occlusion of external objects or the jitter of the scanning device, and significantly improve the robustness of the reflection center point calculation.

[0249] In another alternative embodiment, the boom length measurement device can also be configured with a self-diagnosis and calibration function. The system periodically executes a self-check process, including the detection of the light source intensity of the scanning device, the evaluation of the cleanliness of the reflector, and the integrity test of the communication link. If it is detected that the surface of the reflector is contaminated (such as dust or oil), the system prompts the maintenance personnel to clean the reflector through the human-machine interface; if the light source intensity of the scanning device is lower than the preset value, the emission power is automatically increased or the redundant scanning module is triggered to switch. In the calibration mode, the system controls the boom to extend and retract to a known length (such as the basic length), and compares the measured value with the calibrated value. If the deviation exceeds ±0.5%, the coordinate system transformation parameters are automatically updated or the angular offset of the scanning device is recalibrated to ensure the accuracy of long-term measurement.

[0250] Embodiment III

[0251] Please refer to Figure 4 , Figure 4 which is a schematic structural diagram of another boom length measurement device applied to a crane disclosed in the embodiments of the present invention. Among them, Figure 4The device shown is used to implement an arm length measurement method for a crane described in Embodiment 1. When the arm length measurement device executes the arm length measurement method, it can improve the measurement accuracy of the boom length of the crane. As Figure 4 shown, an arm length measurement device for a crane disclosed in an embodiment of the present invention includes, but is not limited to, the following modules:

[0252] A memory 301 storing executable program code;

[0253] A processor 302 coupled to the memory 301;

[0254] The processor 302 calls the executable program code stored in the memory 301 and executes some or all of the steps in an arm length measurement method for a crane described in Embodiment 1 of the present invention.

[0255] Embodiment 4

[0256] An embodiment of the present invention discloses a computer storage medium. The computer storage medium stores computer instructions, which are used to execute some or all of the steps in an arm length measurement method for a crane described in Embodiment 1 of the present invention when called by a processor.

[0257] The device embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separated. The components shown as modules may or may not be physical modules. They may be located in one place or distributed to multiple network modules. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without creative labor.

[0258] Through the specific descriptions of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product can be stored in a computer-readable storage medium, and the storage medium includes read-only memory (ROM), random access memory (RAM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), one-time programmable read-only memory (OTPROM), electrically-erasable programmable read-only memory (EEPROM), compact disc read-only memory (CD-ROM) or other optical disc memories, magnetic disc memories, tape memories, or any other medium that can be used to carry or store data and is computer-readable.

[0259] Finally, it should be noted that what is disclosed in the embodiments of the present invention is only the preferred embodiments of the present invention, and is only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring arm length applied to a crane, characterized in that: A scanning device is provided at the connection position between the lifting boom of the crane and the lifting turntable, and a reflecting device is provided at the arm head of the lifting boom. The method comprises: Acquire scanning point cloud data obtained by scanning by the scanning device within a preset scanning range; the scanning object of the scanning device within the preset scanning range at least includes the reflecting device; Acquire the current cylinder length of the luffing cylinder of the crane, and filter the scanned point cloud data according to the current cylinder length to obtain reflection point cloud data; the reflection point cloud data is the point cloud data obtained by the scanning device scanning the reflection device; The current length of the crane boom is calculated according to the reflection point cloud data to obtain the measured length of the boom.

2. The arm length measurement method applied to a crane according to claim 1, characterized in that: The preset scanning range corresponds to a plurality of preset scanning angles, and the preset scanning angle is the angle between the scanning direction of the scanning device and the horizontal plane; The acquiring of scanning point cloud data obtained by scanning by the scanning device within a preset scanning range includes: For each of the preset scanning angles, obtaining scanning point data obtained by the scanning device scanning the scanning point corresponding to the preset scanning angle; Integrate the scanning point data corresponding to all the preset scanning angles to obtain scanning point cloud data; Wherein, for each of the scanning point data, the scanning point data includes a first coordinate value of the corresponding scanning point projected in the first coordinate direction, a second coordinate value projected in the second coordinate direction, and a third coordinate value projected in the third coordinate direction; The first coordinate direction is a direction perpendicular to the horizontal plane with the position of the scanning device as the origin, the second coordinate direction is a direction parallel to the horizontal plane with the position of the scanning device as the origin, and the third coordinate direction is a direction perpendicular to the plane formed by the first coordinate direction and the second coordinate direction with the position of the scanning device as the origin.

3. The arm length measurement method applied to a crane according to claim 2, characterized in that: The reflecting device comprises a reflecting plate; The obtaining of the current cylinder length of the luffing cylinder of the crane and filtering the scanned point cloud data according to the current cylinder length to obtain the reflected point cloud data includes: Obtaining the current cylinder length of the luffing cylinder of the crane, and calculating the angle between the lifting boom and the lifting turntable according to the current cylinder length to obtain the lifting angle of the boom; Calculate the scanning filter angle according to the pre-stored basic length of the boom and the length of the reflector; the basic length of the boom is the length of the lifting boom when it is not extended, and the length of the reflector is the length of the reflector in the vertical direction; Filtering the scanned point cloud data according to the boom lifting angle and the scan filtering angle to obtain filtered point cloud data; The filtered point cloud data are screened according to the basic length of the boom to obtain reflected point cloud data.

4. The arm length measurement method applied to a crane according to claim 3, characterized in that: The crane is provided with a first connection point, a second connection point and a third connection point, the first connection point is the connection point between the lifting boom and the lifting turntable, the second connection point is the connection point between the luffing cylinder of the crane and the lifting turntable, and the third connection point is the connection point between the lifting boom and the luffing cylinder of the crane; The obtaining of the current cylinder length of the luffing cylinder of the crane, and calculating the angle between the lifting boom and the lifting turntable according to the current cylinder length to obtain the lifting angle of the boom, includes: Obtaining the current cylinder length of the luffing cylinder of the crane; Calculate the square difference between a pre-stored first connection distance and the current cylinder length to obtain a first calculated value; the first connection distance is the distance between the first connection point and the second connection point; Calculate the sum of the square value of the pre-stored second connection distance and the first calculated value to obtain a second calculated value; the second connection distance is the distance between the first connection point and the third connection point; Calculating the product of the first connection distance and the second connection distance, and multiplying the obtained product by two to obtain a third calculated value; Calculate the quotient of the second calculated value divided by the third calculated value to obtain a fourth calculated value; An arc cosine operation is performed according to the fourth calculated value to obtain the boom lifting angle.

5. The arm length measurement method applied to a crane according to claim 3, characterized in that: The step of calculating the scanning filtering angle according to the pre-stored basic length of the boom and the length of the reflector includes: Calculate the square difference between the basic length of the boom and the length of the reflector to obtain a fifth calculated value; Performing a square root operation on the fifth calculated value to obtain a sixth calculated value; Calculating a quotient of the sixth calculated value divided by the basic length of the boom to obtain a seventh calculated value; An arc cosine operation is performed according to the seventh calculated value to obtain a scanning filter angle.

6. The arm length measurement method applied to a crane according to claim 3, characterized in that: The filtering of the scanned point cloud data according to the boom lifting angle and the scan filtering angle to obtain filtered point cloud data includes: Calculating the difference between the boom lifting angle and the scanning filtering angle to obtain a first filtering angle; Calculating the sum of the boom lifting angle and the scanning filtering angle to obtain a second filtering angle; Filtering the scanned point cloud data according to the first filtering angle and the second filtering angle to obtain filtered point cloud data; Wherein, for each scanning point data in the filtered point cloud data, a preset scanning angle corresponding to the scanning point data is not less than the first filtering angle and not greater than the second filtering angle.

7. The arm length measurement method applied to a crane according to claim 3, characterized in that: The filtering point cloud data is screened according to the basic length of the boom to obtain the reflected point cloud data, including: For each scanning point corresponding to each scanning point data in the filtered point cloud data, the square sum of the first coordinate value and the second coordinate value of the scanning point is calculated to obtain an eighth calculated value, and a square root operation is performed on the eighth calculated value to obtain a scanning reflection distance of the scanning point; the scanning reflection distance is the distance between the scanning point and the scanning device; Filtering all scan point data in the filtering point cloud data according to the basic length of the boom to obtain reflection point cloud data; Wherein, for a scanning point corresponding to each scanning point data in the reflection point cloud data, a scanning reflection distance of the scanning point is greater than the basic length of the boom.

8. A method for measuring arm length applied to a crane according to any one of claims 2 to 7, characterized in that: The step of calculating the current length of the crane boom according to the reflection point cloud data to obtain the measured length of the boom includes: For each scanning point corresponding to the scanning point data in the reflection point cloud data, project the scanning point onto a vertical projection plane to obtain a vertical projection point corresponding to the scanning point; the vertical projection plane is a plane formed by the first coordinate direction and the third coordinate direction; For each of the vertical projection points, determine the nearest neighbor projection point corresponding to the vertical projection point, and calculate the distance between the vertical projection point and the nearest neighbor projection point corresponding to the vertical projection point to obtain the nearest neighbor point spacing corresponding to the vertical projection point; the nearest neighbor projection point is the other vertical projection point with the shortest distance to the vertical projection point; Performing statistical analysis on the distances between the nearest neighbor points corresponding to all the vertical projection points to obtain statistical analysis results; the statistical analysis results at least include distance anomaly analysis results; Screening all the vertical projection points according to the statistical analysis results to obtain a target projection point set; Calculate the first coordinate value of the reflection center point and the third coordinate value of the reflection center point according to all vertical projection points in the target projection point set; the reflection center point is the center point of the reflection device; Determine a second coordinate value of the reflection center point according to the first coordinate value of the reflection center point and the third coordinate value of the reflection center point; Calculate the sum of the squares of the first coordinate value of the reflection center point and the second coordinate value of the reflection center point to obtain a ninth calculated value; A square root operation is performed on the ninth calculated value to obtain the measured length of the boom.

9. A boom length measuring device for a crane, characterized in that: A scanning device is provided at the connection position between the lifting boom of the crane and the lifting turntable, and a reflecting device is provided at the arm head of the lifting boom, and the device comprises: A scanning data acquisition device, used to acquire scanning point cloud data obtained by the scanning device scanning within a preset scanning range; the scanning object of the scanning device within the preset scanning range at least includes the reflecting device; A data filtering and screening device is used to obtain the current cylinder length of the luffing cylinder of the crane, and filter and screen the scanning point cloud data according to the current cylinder length to obtain reflection point cloud data; the reflection point cloud data is the point cloud data obtained by the scanning device scanning the reflection device; The boom length calculation device is used to calculate the current length of the crane boom according to the reflection point cloud data to obtain the measured length of the boom.

10. A boom length measuring device for a crane, characterized in that: The device comprises: A memory storing executable program code; a processor coupled to the memory; The processor calls the executable program code stored in the memory to execute the arm length measurement method applied to a crane as described in any one of claims 1 to 8.

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