A tower crane hoisting object positioning and data processing method

Abstract

The present invention discloses a method for positioning and processing a suspended object of a tower crane, and belongs to the field of comprehensive monitoring of engineering machinery. The method comprises the following steps: calculating the reference point position of the suspension object by two antennas installed on both sides of the central axis of the suspension object parallel to the lateral position of the suspension object and the position of a marker installed on the side of the suspension object facing the laser radar, obtaining the reference point position measurement value and the angle between the reference line and the vertical direction; using a three-dimensional region to represent the spatial range of the suspension object, using a clustering method to obtain a three-dimensional region point cloud cluster, and then obtaining the position and contour of the suspension object, and obtaining the collision contour of the suspension object according to the reference point position measurement value and the angle between the reference line and the vertical direction; for the steel wire rope above the suspension object, the collision area between the steel wire rope above the suspension object and the suspension hook part is regarded as a truncated cone, and obtaining the bottom radius of the truncated cone according to the spacing between the steel wire ropes and the height of the steel wire ropes, and then determining the collision area of ​​the truncated cone. The present invention can ensure the reliability and stability of collision information measurement.

Description

Technical Field

[0001] The present invention belongs to the technical field of comprehensive monitoring of engineering machinery, and more specifically, relates to a tower crane hoisting object positioning and data processing method. Background Art

[0002] Tower cranes are important transportation equipment in the construction field. When tower cranes are transporting goods, the crane's hoisted objects (including hoisted objects, hooks, hoisting wire ropes and other components) may collide with the construction site and surrounding buildings and obstacles.

[0003] To address the above issues, there are currently collision information measurement systems based on lidar and vision. However, when the suspended object moves quickly, it is difficult to accurately detect the overall outline and posture of the suspended object in real time, which brings many hidden dangers to the collision information measurement of the suspended object. Summary of the invention

[0004] In view of the above defects or improvement needs of the prior art, the present invention proposes a tower crane hoisting object positioning and data processing method, which can effectively evaluate the real-time collision profile and movement trend of the hoisting object when the overall profile or posture of the hoisting object cannot be accurately detected, thereby ensuring the reliability and stability of the collision information measurement.

[0005] To achieve the above object, according to one aspect of the present invention, a tower crane hoisting object positioning and data processing method is provided, comprising:

[0006] The reference point position of the hook is calculated by two GNSS antennas installed on both sides of the hook's central axis parallel to the lateral position of the hook and the position of the marker installed on the side of the hook facing the laser radar, and the reference point position measurement value and the angle between the reference line and the vertical direction are obtained, wherein the laser radar is located within a preset range near the cockpit at the root of the boom;

[0007] The spatial range of the hanging object is represented by a three-dimensional region, and the point cloud cluster of the three-dimensional region is obtained by a clustering method, and then the position and contour of the hanging object are obtained. The collision contour of the hanging object is obtained according to the measured value of the reference point position and the angle between the reference line and the vertical direction;

[0008] For the wire rope above the hook, the collision area between the wire rope above the hook and the hook part is regarded as a truncated cone. The bottom radius of the truncated cone is obtained according to the spacing between the wire ropes and the height of the wire ropes, and then the collision area of ​​the truncated cone is determined.

[0009] In some optional implementations, obtaining the reference point position measurement value and the angle between the reference line and the vertical direction includes:

[0010] At time t0, the reference point position of the hook calculated by GNSS is obtained by reading the two GNSS antennas. Among them, the position and direction measured by the dual antennas are fixed relative to the hook reference point;

[0011] The position of the marker is measured by laser radar, wherein the relative position of the marker and the reference point of the hook is fixed;

[0012] Use the measurement data of the center point of the marker within the preset time to calculate the position point set of the hook reference point through the relative position of the marker and the hook reference point The mean of the observation data of the reference position at this time is estimated

[0013] Two calculated values ​​based on the reference position and Get the reference point position measurement value and the angle between the reference line and the vertical direction.

[0014] In some optional embodiments, Get the reference point position measurement value By θ a =λθ p +(1-λ)θ q Get the angle θ between the reference line and the vertical direction a , where λ represents the weight factor, θ p Indicates the angle between the first reference line direction and the vertical direction, θ q It represents the angle between the measured second reference line direction and the vertical direction. The measured first reference line direction is perpendicular to the direction of the GNSS antenna, and the measured second reference line direction is parallel to the vertical center line of the marker.

[0015] In some optional implementation schemes, a three-dimensional region is used to represent the spatial range of the hanging object, and a clustering method is used to obtain a three-dimensional region point cloud cluster, thereby obtaining the position and outline of the hanging object, including:

[0016] A rectangular area is used to represent the spatial range of the hanging object. The rectangular area is relatively fixed to the position of the hook, and the position of the rectangular area is determined by the reference position of the hook.

[0017] Use the clustering method to cluster the point cloud data in the rectangular area to obtain several clusters of point clouds. For each cluster of point clouds, calculate the distance from the centroid of the point cloud cluster to the center of the rectangular parallelepiped. The point cloud cluster with the smallest distance is considered to be the point cloud cluster of the hanging object.

[0018] After obtaining the point cloud cluster belonging to the hoisted object, the envelope surface is obtained by using computational geometry methods. The polyhedron formed by the envelope surface is used to represent the hoisted object, and the position and contour of the hoisted object are obtained.

[0019] In some optional implementation schemes, obtaining the collision profile of the hanging object according to the reference point position measurement value and the angle between the reference line and the vertical direction includes:

[0020] With the reference line as the rotation axis, the object contour is rotated to form a rotating body of the object contour, which is used as the collision contour of the hoisted object and is used for collision distance calculation and interference detection between the hoisted object and surrounding objects. The reference line passes through the reference point The angle with the vertical direction is θ a ;

[0021] Connect the outermost edge of the rotating body of the hoisting object contour with the center of the hook ring to form an enveloping cone-like surface, which serves as the contour interference area of ​​the wire rope under the hook. It is also used for collision distance detection and interference detection between the hoisting object and surrounding objects.

[0022] In some optional implementation schemes, determining the frustum collision area includes:

[0023] The collision area between the hook and the upper wire rope is regarded as a frustum, the top of which is the luffing trolley. The diameter of the circle depends on the spacing between the wire ropes, and the height of the frustum depends on the vertical spacing from the reference position to the luffing trolley.

[0024] Set the yaw angle of the wire rope, and obtain the diameter of the bottom of the truncated table based on the yaw angle, vertical spacing, and spacing of the wire ropes at the trolley.

[0025] In some optional embodiments, the method further comprises:

[0026] The movement of the collision profile of the hoisted object is predicted by predicting the movement of the reference position. The measured reference position value is decomposed into three variables according to the movement directions of the three actuators of the tower crane. A linear equation of each variable is established, and the two parameters of each linear equation are solved using the linear regression method.

[0027] In general, the above technical solutions conceived by the present invention can achieve the following beneficial effects compared with the prior art:

[0028] The collision area of ​​the hoisted object is divided into the hoisted object, the wire rope below the hook, and the wire rope above the hook. Targeted contour determination methods are used for different collision areas. The effectiveness and reliability of collision area detection are taken into account under the premise of accurately positioning the reference position, thereby ensuring the stability of collision information measurement. On this basis, a motion prediction method for hoisted objects is proposed to provide relevant basis for anti-collision control. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of measuring a reference position and a reference line of a hoisted object provided by an embodiment of the present invention;

[0030] Figure 2 It is a schematic diagram of measuring the collision profile of a hoisted object and a wire rope under a hook provided by an embodiment of the present invention;

[0031] Figure 3 It is a schematic diagram of measuring the collision profile of a wire rope above a hook provided by an embodiment of the present invention;

[0032] Figure 4 It is a schematic diagram of the movement direction of a tower crane actuator provided by an embodiment of the present invention;

[0033] In the figure: 1.1-LiDAR, 1.2-LiDAR detection range, 2-GNSS antenna, 3-marker, 4-hook, 5-reference position, 6.1-GNSS centerline, 6.2-marker centerline, 7-wire rope under the hook, 8-hoisted object, 9-rectangular range, 10.1-obstacle, 10.2-interference area between the rectangular range and the obstacle, 11-boom direction, 12-wire rope above the hook. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0035] In the examples of the present invention, "first", "second", etc. are used to distinguish different objects rather than to describe a specific order or sequence.

[0036] The present invention provides a tower crane hoisting object positioning and data processing method, including a method for measuring a reference position and a reference line of a hoisting object, a method for measuring a collision profile of a hoisting object (including a hoisting object 8, a steel wire rope 7 below a hook, and a steel wire rope 12 above the hook), and a method for predicting the motion of a hoisting object.

[0037] like Figure 1 As shown, two GNSS antennas 2 are installed at positions parallel to the hook's horizontal direction on both sides of the central axis of the hook 4, and the position and direction measured by the dual antennas are fixed relative to the reference point 5 of the hook. Therefore, the reference point position of the hook calculated by GNSS is obtained by reading at time t0

[0038] The laser radar 1.1 is installed near the cockpit at the root of the boom and rotates with the boom. The laser radar detection range 1.2 is as follows Figure 1As shown in the figure, a marker 3 is installed on the side of the hook facing the laser radar, and the relative position of the marker and the hook reference point 5 is fixed. The position of the marker point (i.e., the center of the marker 3) is measured using the laser radar after conversion to the same coordinate system. Due to shaking, vibration and measurement equipment errors, the observation data of the marker point over a period of time is used to calculate the position point set of the hook reference point through the relative position of the marker and the hook reference point. The mean of the observation data of the reference position at this time is estimated:

[0039]

[0040] N is the number of observation data of the landmark points within a period of time, which can be taken as 5, the sampling period is 20ms, ΔT=N*20ms.

[0041] Thus, two calculated values ​​of the reference position are obtained and against The measured reference line direction 6.1 is perpendicular to the direction of the GNSS antenna (i.e. the angle between the measured reference line direction 6.1 and the vertical direction is θ p );against The measured reference line direction 6.2 is parallel to the vertical center line of the marker (i.e. the angle between the measured reference line direction 6.2 and the vertical direction is θ q ). According to the actual situation, the weight factor λ∈[0,1] is taken, and the reference position measurement value at time t0 is:

[0042]

[0043] The angle between the reference line and the vertical direction is:

[0044] θ a =λθ p +(1-λ)θ q

[0045] The value of λ will be adjusted dynamically according to the working condition of the tower crane. When the GNSS signal is very good and completely normal, λ can be set to 1; when there are problems with GNSS data settlement and the lidar detection is normal, λ can be set to 0; when the GNSS signal is weak and the lidar detection has certain flaws, λ can be set to 0.5.

[0046] like Figure 2As shown, the hoisted object is located below the hook, so a larger rectangular area 9 is first used to represent the spatial range where the hoisted object may exist, and this area is relatively fixed with the position of the hook. Since the reference position of the hook has been measured, the position of the spatial rectangular area can also be obtained. When the tower crane is working, obstacles 10.1 and the working plane sometimes invade the rectangular area, as shown in 10.2. Therefore, it is necessary to cluster the points in the rectangular area first. Clustering the point cloud data in the rectangular area using the clustering method DBSCAN can obtain several clusters of point clouds. For each cluster of point clouds, the distance from the center of mass to the center of the cuboid is calculated, and the point cloud cluster with the smallest distance is considered to be the point cloud cluster of the hoisted object. After obtaining the point cloud cluster belonging to the hoisted object, the envelope surface of the point cloud cluster is obtained by using computational geometry methods. The polyhedron formed by the envelope surface is used to represent the hoisted object, so that the position and contour of the hoisted object are obtained. Furthermore, since the hoisted object will rotate in the air, the contour in this posture cannot simply represent the collision contour of the hoisted object. Therefore, further processing is required to obtain the baseline measured by the above method (the baseline passes through the reference point The angle with the vertical direction is θ a ) is the rotation axis, and the contour of the hoisted object is rotated to form a rotating body, which is the collision contour of the hoisted object, and is used for collision distance calculation and interference detection between the hoisted object and surrounding objects. The outermost edge of the rotating body of the hoisted object contour is connected with the center of the hook ring to form an enveloping cone-like surface, which is the contour interference area of ​​the wire rope under the hook, and is also used for collision distance detection and interference detection between the hoisted object and surrounding objects.

[0047] like Figure 3 As shown, the luffing trolley and the boom 11 are in the same direction. For the wire rope above the hook (the wire rope between the hook and the luffing trolley on the boom). Since the hook and the wire rope above will swing in a cone-like manner during the operation of the tower crane, this part of the collision area can be regarded as a frustum. The top of the frustum is at the luffing trolley. The diameter of the circle depends on the spacing between the wire ropes. The radius r of the top of the frustum is equal to half of the spacing of the wire ropes at the luffing trolley. The height of the frustum depends on the vertical spacing from the reference position to the luffing trolley. The height of the frustum is equal to the height h of the wire rope above the hook. Since the reference position of the hook is known and the height of the boom is fixed, the height h of the wire rope can be obtained. Since the collision area detection of this part does not need to be so accurate, but must include all possible movement positions of the wire rope, the swing angle α of the wire rope can take a fixed value (5°-10°), and the diameter of the bottom of the frustum is obtained according to the swing angle, vertical spacing, and spacing of the wire ropes at the trolley.

[0048] Then, the radius of the bottom of the cone is:

[0049] R=r+h*tgα

[0050] The present invention provides a motion prediction method for a tower crane hoisting object, which can predict the motion trajectory of the hoisted object during the operation of the tower crane. The method can be applied to the scenes of early warning and obstacle avoidance of the tower crane. Here, the motion of the collision contour of the hoisted object is predicted by predicting the motion of the reference position. The measured reference position value is decomposed into three variables according to the motion directions of the three actuators of the tower crane, and a linear equation of each variable is established, and the two parameters of each linear equation of one variable are solved using a linear regression method.

[0051] like Figure 4 As shown in the figure, according to the action direction of the tower crane actuator, the reference position value at time i is decomposed into a i =[γ i ,l i ,h i ]. Taking the arm rotation angle θ as an example, assuming that the linear regression equation is γ=b0+b1t, then according to the time from t0 to t n-1 Solving for b0 and b1 at the time instant gives:

[0052]

[0053] The linear regression analysis method of l and h is similar. n Substitute into the linear regression equation at any time and get t n Moment of [γ n ,l n ,h n ], and further obtain the predicted position a of the reference position n =[γ n ,l n ,h n ] to determine the predicted position of the hoisted object.

[0054] In summary, the present invention combines GNSS detection and laser radar detection of markers to achieve the positioning of the reference position, and further obtains the collision area of ​​the hoisted object, the wire rope under the hook, and the wire rope above the hook, ensuring the reliability of the collision area detection. Although there are some redundant areas, the rationality and effectiveness of the redundant areas are fully considered. Finally, the prediction of the running trajectory of the reference position is achieved.

[0055] It should be pointed out that, according to the needs of implementation, the various steps / components described in this application can be split into more steps / components, and two or more steps / components or partial operations of steps / components can be combined into new steps / components to achieve the purpose of the present invention.

[0056] It will be easily understood by those skilled in the art that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A tower crane hoisting object positioning and data processing method, characterized in that: include: The reference point position of the hook is calculated by two GNSS antennas installed on both sides of the hook's central axis parallel to the lateral position of the hook and the position of the marker installed on the side of the hook facing the laser radar, and the reference point position measurement value and the angle between the reference line and the vertical direction are obtained, wherein the laser radar is located within a preset range near the cockpit at the root of the boom; The spatial range of the hanging object is represented by a three-dimensional region, and the point cloud cluster of the three-dimensional region is obtained by a clustering method, and then the position and contour of the hanging object are obtained. The collision contour of the hanging object is obtained according to the measured value of the reference point position and the angle between the reference line and the vertical direction; For the wire rope above the hook, the collision area between the wire rope above the hook and the hook part is regarded as a truncated cone. The bottom radius of the truncated cone is obtained according to the spacing between the wire ropes and the height of the wire ropes, and then the collision area of ​​the truncated cone is determined; The three-dimensional region is used to represent the spatial range of the hanging object, and the clustering method is used to obtain the three-dimensional region point cloud cluster, and then the position and outline of the hanging object are obtained, including: A rectangular area is used to represent the spatial range of the hanging object. The rectangular area is relatively fixed to the position of the hook, and the position of the rectangular area is determined by the reference position of the hook. Use the clustering method to cluster the point cloud data in the rectangular area to obtain several clusters of point clouds. For each cluster of point clouds, calculate the distance from the centroid of the point cloud cluster to the center of the rectangular parallelepiped. The point cloud cluster with the smallest distance is considered to be the point cloud cluster of the hanging object. After obtaining the point cloud cluster belonging to the hoisted object, the envelope surface is obtained by using computational geometry methods. The polyhedron formed by the envelope surface is used to represent the hoisted object, and the position and contour of the hoisted object are obtained.

2. The method according to claim 1, characterized in that Get the reference point position measurement value and the angle between the reference line and the vertical direction, including: At time t0, the reference point position of the hook calculated by GNSS is obtained by reading the two GNSS antennas. Among them, the position and direction measured by the dual antennas are fixed relative to the hook reference point; The position of the marker is measured by laser radar, wherein the relative position of the marker and the reference point of the hook is fixed; Use the measurement data of the center point of the marker within the preset time to calculate the position point set of the hook reference point through the relative position of the marker and the hook reference point The mean of the observation data of the reference position at this time is estimated Two calculated values ​​based on the reference position and Get the reference point position measurement value and the angle between the reference line and the vertical direction.

3. The method according to claim 2, characterized in that Depend on Get the reference point position measurement value By θ a =λθ p +(1-λ)θ q Get the angle θ between the reference line and the vertical direction a , where λ represents the weight factor, θ p Indicates the angle between the first reference line direction and the vertical direction, θ q It represents the angle between the measured second reference line direction and the vertical direction. The measured first reference line direction is perpendicular to the direction of the GNSS antenna, and the measured second reference line direction is parallel to the vertical center line of the marker.

4. The method according to claim 3, characterized in that The collision profile of the hanging object is obtained based on the measured value of the reference point position and the angle between the reference line and the vertical direction, including: With the reference line as the rotation axis, the object contour is rotated to form a rotating body of the object contour, which is used as the collision contour of the hoisted object and is used for collision distance calculation and interference detection between the hoisted object and surrounding objects. The reference line passes through the reference point The angle with the vertical direction is θ a ; Connect the outermost edge of the rotating body of the hoisting object contour with the center of the hook ring to form an enveloping cone-like surface, which serves as the contour interference area of ​​the wire rope under the hook. It is also used for collision distance detection and interference detection between the hoisting object and surrounding objects.

5. The method according to claim 1, characterized in that Determine the frustum collision area, including: The collision area between the hook and the upper wire rope is regarded as a frustum, the top of which is the luffing trolley. The diameter of the circle depends on the spacing between the wire ropes, and the height of the frustum depends on the vertical spacing from the reference position to the luffing trolley. Set the yaw angle of the wire rope, and obtain the diameter of the bottom of the truncated table based on the yaw angle, vertical spacing, and spacing of the wire ropes at the trolley.

6. The method according to claim 1, characterized in that The method further comprises: The movement of the collision profile of the hoisted object is predicted by predicting the movement of the reference position. The measured reference position value is decomposed into three variables according to the movement directions of the three actuators of the tower crane. A linear equation of each variable is established, and the two parameters of each linear equation are solved using the linear regression method.

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