An Unmanned Aerial Vehicle Route Planning Method and System for Inspecting Construction Surfaces

Abstract

The present invention relates to a method and system for unmanned aerial vehicle (UAV) flight path planning for building construction site inspection. The method includes Step 1: obtaining the contour lines of each individual building based on the construction site information and selecting a take-off point; obtaining the minimum bounding rectangle of the contour lines; formulating a two-dimensional flight path of the UAV according to the take-off point and the minimum bounding rectangle. Step 2: determining the relative flight altitude of the UAV with respect to the building construction surface, obtaining a rectangular boundary in three-dimensional space based on the relative flight altitude and the minimum bounding rectangle, and automatically fitting a three-dimensional surface based on the set of rectangular boundaries. Step 3: constructing a linear planar buffer zone based on the two-dimensional flight path; constructing a planar buffer zone of surface type based on the minimum bounding rectangle; generating an inspection flight path based on the linear planar buffer zone, the planar buffer zone of surface type and the three-dimensional surface. Step 4: setting parameters in the inspection flight path. The present invention provides a set of adaptable flight path planning processes, which can not only ensure the inspection efficiency, but also obtain more comprehensive inspection data from multiple perspectives.

Description

Technical Field

[0001] The present invention relates to the technical field of construction management, and in particular to a method and system for unmanned aerial vehicle (UAV) route planning for building construction surface inspection. Background Art

[0002] Inspecting the construction site is an important means to avoid safety accidents caused by insufficient monitoring and untimely rectification, and is an effective way to understand the construction site situation and assist supervision and management. At present, the inspection work is an irregular spot check by inspectors on site, which is usually restricted by time and space. Especially in high-difficulty and large-scale projects, it is interfered by objective factors such as environment, geography, climate and subjective personnel conditions, and it is difficult to ensure the inspection frequency and quality.

[0003] With the development of UAV technology, UAVs are more and more widely used in construction projects. At the same time, technicians also try to use UAVs for on-site inspection work. During the UAV inspection operation, the operator needs to manually assist in planning the task route to ensure that it basically meets the operation requirements, and there is no adaptive route planning process. This not only consumes a lot of time and energy, but also usually makes it difficult to obtain aerial inspection data from multiple perspectives of the inspection object while ensuring the inspection efficiency. In addition, the aerial inspection under a unified safe flight altitude is difficult to meet the refined data collection of different inspection targets in complex projects. Summary of the Invention

[0004] The present invention provides a method and system for UAV route planning for building construction surface inspection to solve the above technical problems.

[0005] To solve the above technical problems, the present invention provides a method for UAV route planning for building construction surface inspection, including the following steps:

[0006] Step 1: Obtain the contour lines of each individual building based on the construction site information, and select the take-off point of the UAV; obtain the minimum bounding rectangle of the contour lines; formulate a two-dimensional route for the UAV to fly according to the take-off point and the minimum bounding rectangle;

[0007] Step 2: Determine the relative flight altitude between the UAV and the building construction surface, obtain a rectangular boundary in three-dimensional space based on the relative flight altitude and the minimum bounding rectangle, and automatically fit a three-dimensional surface based on the set of rectangular boundaries;

[0008] Step 3: Construct a linear plane buffer based on the two-dimensional route; construct a planar buffer based on the minimum bounding rectangle; map the union of the linear plane buffer and the planar buffer onto the three-dimensional surface in Step 2 to generate an inspection route;

[0009] Step 4: Set the parameters in the inspection route.

[0010] Preferably, step 1 includes:

[0011] Step 1.1: Collect construction site information, where the construction site information includes at least an engineering plan, distribution and height information of construction buildings. Among them, the building height is H Bi ;

[0012] Step 1.2: Select the take-off point S of the unmanned aerial vehicle and mark it on the engineering plan;

[0013] Step 1.3: Obtain the contour line of the single building from the engineering plan, and define the key point K with the midpoint plane coordinates of the minimum bounding rectangle of the contour line i ;

[0014] Step 1.4: Based on the key points K = {K1, K2,..., K i ,......K n}, formulate a two-dimensional route for the unmanned aerial vehicle to fly.

[0015] Preferably, in step 1.4, the shortest path planning algorithm is used to calculate the shortest path passing through all key points K i in sequence as the two-dimensional route for the unmanned aerial vehicle to fly.

[0016] Preferably, step 2 includes:

[0017] Step 2.1: Determine the relative flight height h of the unmanned aerial vehicle and the building construction surface according to the minimum size l of the smallest target of interest within the construction floor:

[0018]

[0019] where f is the focal length of the camera lens; a is the pixel size; the minimum size l of the smallest target of interest takes the minimum value among the length, width, and height of the minimum bounding box of the smallest target of interest; n is the number of pixels;

[0020] Step 2.2: Obtain the minimum bounding rectangle s of the contour line i and the flight height information corresponding to the single building Add the flight height information H i to the minimum bounding rectangle s i and define it as the rectangular boundary S in three-dimensional space i , and obtain the set of rectangular boundaries Set = {S1, S2,..., S i ,..., S n} in three-dimensional space;

[0021] Step 2.3: According to all the sets of rectangular boundaries Set in different height planes, automatically fit a three-dimensional surface so that each boundary is included therein as the safety inspection operation surface.

[0022] Preferably, the said step 3 includes:

[0023] Step 3.1: Taking the two-dimensional route obtained in step 1.4 as the center, defining a first buffer radius d1, and constructing the linear plane buffer zone;

[0024] Step 3.2: Taking the minimum bounding rectangle of the single building as the center, defining a second buffer radius d2, and constructing the planar buffer zone;

[0025] Step 3.3: Performing a union operation on the linear plane buffer zone and the planar buffer zone;

[0026] Step 3.4: Extracting the boundary of the merged buffer zone and projecting the boundary of the buffer zone onto the safety inspection operation surface generated in step 2.3, and the obtained space curve is the inspection flight path.

[0027] Preferably, the said step 4 includes:

[0028] Step 4.1: Obtaining the spatial coordinates of the drone in the inspection flight path as (X0, Y0, Z0), and the coordinate of the center point of the building construction surface is

[0029] Step 4.2: The drone lens always faces the direction of the center point of the building construction surface closest to it;

[0030] Step 4.3: The pitch angle α of the drone lens in the inspection flight path is:

[0031]

[0032] The present invention also provides a drone route planning system for building construction surface inspection, including:

[0033] A two-dimensional route formulation unit, configured to obtain the contour lines of each single building based on the construction site information and select the take-off point of the drone; obtain the minimum bounding rectangle of the contour lines; formulate the two-dimensional route of the drone flight according to the take-off point and the minimum bounding rectangle;

[0034] A three-dimensional surface acquisition unit, configured to determine the relative flight height between the drone and the building construction surface, obtain the rectangular boundaries in the three-dimensional space based on the relative flight height and the minimum bounding rectangle, and automatically fit the three-dimensional surface based on the set of rectangular boundaries;

[0035] An inspection route generation unit for constructing a linear planar buffer based on the two-dimensional route; constructing a planar buffer based on the minimum bounding rectangle; mapping the union of the linear planar buffer and the planar buffer onto the automatically fitted three-dimensional surface to generate an inspection route; and

[0036] A parameter setting unit for setting parameters in the inspection route.

[0037] Compared with the prior art, the unmanned aerial vehicle (UAV) route planning method and system for building construction surface inspection provided by the present invention have the following advantages:

[0038] 1. The UAV route planning method provided by the present invention forms a set of adaptable route planning processes. While the route planning result can ensure the inspection efficiency, it can also capture multiple perspectives of the inspection object, and the obtained inspection data is more comprehensive;

[0039] 2. The route planned by the present invention not only ensures the safety of UAV operations, but also meets the refined data collection of different inspection targets in complex projects;

[0040] 3. The present invention promotes the implementation and application of UAV inspection in large residential construction projects. Description of the Drawings

[0041] Figure 1 It is a block diagram of a UAV route planning system for building construction surface inspection in a specific embodiment of the present invention

[0042] Figure 2 It is a flowchart of a UAV route planning method for building construction surface inspection in a specific embodiment of the present invention;

[0043] Figure 3 It is a schematic diagram of a two-dimensional route of UAV flight in a specific embodiment of the present invention;

[0044] Figure 4 It is a schematic diagram of the set of all rectangular boundaries in three-dimensional space in a specific embodiment of the present invention;

[0045] Figure 5 It is a schematic diagram of a safety inspection operation surface in a specific embodiment of the present invention;

[0046] Figure 6 It is a schematic diagram of the union boundary of the inspection object buffer in a specific embodiment of the present invention;

[0047] Figure 7 It is a schematic diagram of the finally generated inspection route in a specific embodiment of the present invention.

[0048] In the figure: 100 - system, 101 - two - dimensional route planning unit, 102 - three - dimensional surface acquisition unit, 103 - inspection flight path generation unit, 104 - parameter setting unit. Detailed implementation mode

[0049] In order to describe the technical solution of the above - mentioned invention in more detail, the following specific embodiments are listed to prove the technical effect; it should be emphasized that these embodiments are used to illustrate the present invention and not to limit the scope of the present invention.

[0050] The present invention provides a drone route planning system for building construction surface inspection, as Figure 1 shown, including:

[0051] A two - dimensional route planning unit 101, configured to obtain the contour lines of each individual building based on the construction site information, and select the take - off point of the drone; obtain the minimum bounding rectangle of the contour lines; and formulate a two - dimensional route for the drone to fly according to the take - off point and the minimum bounding rectangle.

[0052] A three - dimensional surface acquisition unit 102, configured to determine the relative flight height between the drone and the building construction surface, obtain a rectangular boundary in three - dimensional space based on the relative flight height and the minimum bounding rectangle, and automatically fit a three - dimensional surface based on the set of rectangular boundaries.

[0053] An inspection flight path generation unit 103, configured to construct a linear plane buffer based on the two - dimensional route; construct a planar plane buffer based on the minimum bounding rectangle; map the union of the linear plane buffer and the planar plane buffer onto the automatically - fitted three - dimensional surface to generate an inspection flight path; and

[0054] A parameter setting unit 104, configured to set the parameters in the inspection flight path.

[0055] The present invention also provides a method for drone route planning for building construction surface inspection, as Figure 2 shown, and in combination with Figures 3 to 7 includes the following steps:

[0056] Step 1: Obtain the contour lines of each individual building based on the construction site information, and select the take - off point of the drone; obtain the minimum bounding rectangle of the contour lines, where the minimum bounding rectangle of the contour lines is defined as the smallest rectangle that can enclose all the contour lines of a certain individual building. Formulate a two - dimensional route for the drone to fly according to the take - off point and the minimum bounding rectangle. In some embodiments, this step can be executed by the two - dimensional route planning unit 101 in the system 100.

[0057] The specific steps of Step 1 may include:

[0058] Step 1.1: Collect construction site information, where the construction site information includes at least an engineering plan, the distribution and height information of construction buildings. Among them, the building height is H Bi (unit: m);

[0059] Step 1.2: Select the take-off point S of the unmanned aerial vehicle (UAV) and mark it on the engineering plan;

[0060] Step 1.3: Obtain the contour line of a single building from the engineering plan, and define the key point K with the midpoint plane coordinates of the minimum bounding rectangle of the contour line i ;

[0061] Step 1.4: Based on the key points K = {K1, K2,..., K i ,......K n}, formulate a two-dimensional flight route for the UAV. In some embodiments, the shortest path planning algorithm can be used to calculate the shortest path passing through all the key points K i on the path in sequence, as the two-dimensional flight route of the UAV. Taking the 6 key points shown in Figure 3 as an example, K = {K1, K2, K3, K4, K5, K6}, and thus the two-dimensional line shown by the dashed line in Figure 3 can be obtained.

[0062] Step 2: Determine the relative flight height of the UAV with respect to the building construction surface. Based on the relative flight height and the minimum bounding rectangle, obtain the rectangular boundary in the three-dimensional space, and automatically fit the three-dimensional surface based on the set of rectangular boundaries. In some embodiments, this step can be executed by the three-dimensional surface acquisition unit 102 in the system 100.

[0063] The specific steps of Step 2 may include:

[0064] Step 2.1: Determine the relative flight height h (unit: m) of the UAV with respect to the building construction surface according to the minimum size l (unit: m) of the minimum interesting target within the construction floor surface:

[0065]

[0066] Among them, f (unit: mm) is the focal length of the camera lens; a (unit: μm) is the pixel size; the minimum size l of the minimum interesting target takes the minimum value among the length, width, and height of the minimum bounding box of the minimum interesting target; n is the number of pixels. Since in actual project applications, it is considered that at least 2 or more pixels are required to clearly reflect the inspection target size l, so n≥2 is defined.

[0067] In Figures 3 to 7In the illustrated embodiment, according to the diameter l = 0.03 m of the pre-embedded pipeline in the construction floor; the focal length f = 8.8 mm of the UAV camera lens; the pixel size a = 2.41 μm; after verification, setting n - 6 can ensure that the template object is clearly visible; then the relative flight height h is:

[0068]

[0069] Step 2.2: Obtain the minimum bounding rectangle s of the contour line i and the flight height information corresponding to the single entity For the minimum bounding rectangle s i Add the flight height information H i Define it as the rectangular boundary S in the three-dimensional space i , and obtain the set of rectangular boundaries Set = {S1, S2,..., S i ,... S n} in the three-dimensional space. Still taking the embodiment shown as an example, the set of rectangular boundaries Set = {S1, S2, S3, S4, S5, S6}, and then the set of rectangular boundaries shown as such can be obtained; Figures 3 to 7 In the illustrated embodiment, the set of rectangular boundaries Set = {S1, S2, S3, S4, S5, S6}, and then the set of rectangular boundaries shown as such can be obtained; Figure 4 shown.

[0070] Step 2.3: According to all the sets of rectangular boundaries Set in the above different height planes, use the method of fitting surfaces by embedding surfaces to automatically fit a three-dimensional surface so that each boundary is included therein, as the safety inspection operation surface, as shown Figure 5 in the figure.

[0071] Step 3: Construct a linear plane buffer based on the two-dimensional route; construct a planar buffer based on the minimum bounding rectangle; map the union of the linear plane buffer and the planar buffer onto the three-dimensional surface in Step 2 to generate an inspection route. In some embodiments, this step can be executed by the inspection route generation unit 103 in the system 100.

[0072] The specific steps of Step 3 may include:

[0073] Step 3.1: Taking the two-dimensional route obtained in Step 1.4 as the center, define a first buffer radius d1, such as 5 m, to construct the linear plane buffer;

[0074] Step 3.2: Taking the minimum bounding rectangle of the single building as the center, define a second buffer radius d2, such as 5 m, to construct the planar buffer;

[0075] Step 3.3: Perform a union operation on all the above linear plane buffers and planar buffers, as shown Figure 6 in the figure;

[0076] Step 3.4: Extract the boundary of the merged buffer, and project the buffer boundary onto the safety inspection operation surface generated in Step 2.3. The resulting space curve is the inspection route, as Figure 7 shown.

[0077] Step 4: Set parameters in the inspection route. In some embodiments, this step may be executed by the parameter setting unit 104 in the system 100.

[0078] The specific steps of Step 4 may include:

[0079] Step 4.1: Obtain the spatial coordinates of the drone in the inspection route as (X0, Y0, Z0), and the coordinates of the center point of the building construction surface are

[0080] Step 4.2: The drone lens always faces the direction of the center point of the building construction surface closest to it;

[0081] Step 4.3: The pitch angle α of the drone lens in the inspection route is calculated from the spatial coordinates of the drone and the coordinates of the center point of the building construction surface closest to it:

[0082]

[0083] Using the above method, the resulting route planning result can capture multiple perspectives of the inspection object while ensuring the inspection efficiency, and the obtained inspection data is more comprehensive; the variable altitude route not only ensures the safety of the drone operation, but also meets the refined data collection of different inspection targets in complex projects.

[0084] In summary, the method for unmanned aerial vehicle (UAV) route planning for building construction site inspection provided by the present invention includes the following steps: Step 1: Obtain the contour lines of each individual building based on the construction site information, and select the take-off point of the UAV; obtain the minimum bounding rectangle of the contour lines; formulate a two-dimensional route for the UAV flight according to the take-off point and the minimum bounding rectangle. Step 2: Determine the relative flight altitude of the UAV with respect to the building construction surface, obtain a rectangular boundary in three-dimensional space based on the relative flight altitude and the minimum bounding rectangle, and automatically fit a three-dimensional surface based on the set of rectangular boundaries. Step 3: Construct a linear planar buffer zone based on the two-dimensional route; construct a planar buffer zone of surface type based on the minimum bounding rectangle; map the union of the linear planar buffer zone and the planar buffer zone of surface type onto the three-dimensional surface in Step 2 to generate an inspection route. Step 4: Set the parameters in the inspection route. The UAV route planning method provided by the present invention forms a set of adaptable route planning processes, and the route planning result can ensure the inspection efficiency while capturing multiple perspectives of the inspection object and obtaining more comprehensive inspection data; the route planned by the present invention not only ensures the safety of UAV operations, but also meets the refined data collection for different inspection objectives in complex projects; the present invention promotes the implementation of UAV inspection in large-scale residential construction projects.

[0085] Obviously, those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalent technologies, the present invention is also intended to include these modifications and variations.

Claims

1. A method for UAV route planning for building construction surface inspection, characterized in that, It includes the following steps: Step 1: Obtain the contour lines of each single building based on the construction site information, and select the take-off point of the drone; obtain the minimum bounding rectangle of the contour lines; formulate a two-dimensional route for the drone flight according to the take-off point and the minimum bounding rectangle; The said Step 1 includes: Step 1.1: Collect construction site information, where the construction site information includes at least an engineering plan, the distribution and height information of construction buildings, and among them, the building height is H Bi ; Step 1.2: Select the take-off point S of the drone and mark it on the engineering plan; Step 1.3: Obtain the outline of the single building from the engineering plan, and define the key point K with the midpoint plane coordinates of the minimum bounding rectangle of the outline i ; Step 1.4: Based on the key points K = {K1, K2,..., K i ,......K n}, use the shortest path planning algorithm to calculate the shortest path that sequentially passes through all the key points K i on the path, and take it as the two-dimensional route for the UAV to fly; Step 2: Determine the relative flight height of the drone from the building construction surface. Based on the relative flight height and the minimum bounding rectangle, obtain the rectangular boundary in the three-dimensional space, and automatically fit the three-dimensional surface based on the set of rectangular boundaries; Step 3: Construct a linear plane buffer based on the two-dimensional route; construct a planar buffer based on the minimum bounding rectangle; map the union of the linear plane buffer and the planar buffer onto the three-dimensional surface in Step 2 to generate an inspection route; Step 4: Set the parameters in the inspection route.

2. The method for unmanned aerial vehicle route planning for building construction surface inspection according to claim 1, wherein, The said Step 2 includes: Step 2.1: Determine the relative flight height h of the drone from the building construction surface according to the minimum size l of the smallest target of interest within the construction floor: where f is the focal length of the camera lens; a is the pixel size; the minimum size l of the smallest target of interest takes the minimum of the length, width, and height of the minimum bounding box of the smallest target of interest; n is the number of pixels; Step 2.2: Obtain the minimum bounding rectangle s of the contour line i and the flight altitude information corresponding to this monomer For the minimum bounding rectangle s i add the flight altitude information H i and define it as the rectangular boundary S in three-dimensional space i , obtaining the set of rectangular boundaries Set = {S1, S2,..., S i ,...S n}; Step 2.3: Automatically fit the three-dimensional surface based on all the sets of rectangular boundaries Set in different height planes so that each boundary is included therein as the safety inspection operation surface.

3. The method for unmanned aerial vehicle route planning for building construction surface inspection according to claim 2, wherein, The said Step 3 includes: Step 3.1: Take the two-dimensional route obtained in Step 1.4 as the center, define the first buffer radius d1, and construct the linear plane buffer; Step 3.2: Take the minimum bounding rectangle of the single building as the center, define the second buffer radius d2, and construct the planar buffer; Step 3.3: Perform the union processing on the linear plane buffer and the planar buffer; Step 3.4: Extract the boundary of the merged buffer, and project the buffer boundary onto the safety inspection operation surface generated in Step 2.

3. The obtained space curve is the inspection route.

4. The method for unmanned aerial vehicle route planning for building construction surface inspection according to claim 3, characterized in that, The said Step 4 includes: Step 4.1: Obtain the spatial coordinates of the UAV in the inspection route as (X0, Y0, Z0), and the coordinate of the center point of the building construction surface is Step 4.2: The drone lens always faces the direction of the center point of the building construction surface closest to it; Step 4.3: The pitch angle α of the drone lens in the inspection route is:

5. An unmanned aerial vehicle route planning system for building construction surface inspection, characterized in that It includes: A two-dimensional route formulation unit, which is used to obtain the contour lines of each single building based on the construction site information, and select the take-off point of the drone; Obtain the minimum bounding rectangle of the contour lines; Formulate a two-dimensional route for the drone flight according to the take-off point and the minimum bounding rectangle; The method for formulating the two-dimensional route includes: Collect construction site information, where the construction site information at least includes an engineering plan, the distribution and height information of construction buildings, and among them, the building height is H Bi ; Select the take-off point S of the drone and mark it on the engineering plan; Obtain the contour line of the single building from the engineering plan view, and define the key point K with the midpoint plane coordinates of the minimum bounding rectangle of the contour line i ; Based on the key points K = {K1, K2,..., K i ,......K n}, use the shortest path planning algorithm to calculate the shortest path passing through all the key points K i on the path in sequence, which is used as the two-dimensional route for the UAV to fly; A three-dimensional surface acquisition unit, which is used to determine the relative flight height of the drone from the building construction surface. Based on the relative flight height and the minimum bounding rectangle, obtain the rectangular boundary in the three-dimensional space, and automatically fit the three-dimensional surface based on the set of rectangular boundaries; An inspection route generation unit is configured to construct a linear planar buffer based on the two-dimensional route; construct a planar buffer of a planar type based on the minimum bounding rectangle; map the union of the linear planar buffer and the planar buffer of the planar type onto the automatically fitted three-dimensional surface to generate an inspection route; and A parameter setting unit is configured to set parameters in the inspection route.

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