A method for planning the grinding trajectory of wind turbine blades, electronic equipment and storage medium

Abstract

This invention relates to the field of wind turbine blade grinding technology, and particularly to a method, electronic device, and storage medium for wind turbine blade grinding trajectory planning. The method includes: acquiring model parameters and grinding parameters of the wind turbine blade; generating a compact directed bounding box of the wind turbine blade using the directed bounding box method; determining the initial tangent plane and its expansion direction required by the isoplanar method; obtaining a preliminary grinding trajectory using the isoplanar method; obtaining a set of grinding points through discretization; removing redundant points located outside the surface boundary of the grinding point set through grinding point classification; and generating the final robot grinding trajectory pose, thus completing the wind turbine blade grinding trajectory planning. This invention enables efficient and automatic planning of the robot's grinding trajectory in wind turbine blade grinding applications, ensuring grinding quality while saving manpower and time costs and improving production efficiency.

Description

Technical Field

[0001] This invention relates to the field of wind turbine blade grinding technology, and in particular to a wind turbine blade grinding trajectory planning method, electronic device and storage medium. Background Technology

[0002] Wind turbine blades are one of the most important structural components of wind turbine units. Their surface integrity and profile accuracy have a crucial impact on the energy conversion efficiency, service life, and operational reliability of the turbine. Grinding and reprocessing the blade surface is an important method for maintaining the profile quality of wind turbine blades. Wind turbine blades are large-sized, complex curved surface components made of fiberglass. The grinding process generates a large amount of fine fibers and harmful dust. Currently, the common method is manual grinding, which can seriously affect the health of workers.

[0003] Using grinding robots to grind wind turbine blades offers advantages such as reduced operating costs and dust hazards, shorter blade delivery cycles, and guaranteed surface processing quality. However, the large size and complex structure of wind turbine blades limit the realization of automated grinding, with a key challenge being the rational planning of grinding trajectories. Currently, trajectory planning for grinding robots mainly relies on manual teaching. With the assistance of compliant devices, it is possible to grind simple surfaces, but it is difficult to plan trajectories for large-sized, complex curved components. Summary of the Invention

[0004] To address the challenge of automating the grinding of wind turbine blades, this invention provides a method for planning grinding trajectories for wind turbine blades, an electronic device, and a storage medium, which can efficiently and automatically plan grinding trajectories for wind turbine blades.

[0005] In a first aspect, embodiments of the present invention provide a method for planning the grinding trajectory of wind turbine blades, including:

[0006] Obtain the model parameters and grinding parameters of the wind turbine blade; wherein, the model parameters include the 3D model data of the wind turbine blade and a set of subsurfaces consisting of all subsurfaces that need to be ground, and the grinding parameters include the roller diameter D of the grinding head. r Grinding feed speed v feed Setting tolerance ε set and jump speed v jump ;

[0007] Based on the 3D model data of the wind turbine blade, a compact oriented bounding box of the wind turbine blade is generated using the oriented bounding box method.

[0008] Based on the compact oriented bounding box of the wind turbine blade, the initial tangent plane and the tangent plane extension direction required by the isoplanar method are determined;

[0009] Based on the model parameters of the wind turbine blade, the grinding parameters, the determined initial cutting plane and the direction of cutting plane expansion, the preliminary grinding trajectory is obtained by the isoplanar method.

[0010] Based on the obtained preliminary grinding trajectory and the grinding parameters, a set of grinding points is obtained through discretization.

[0011] The obtained set of grinding points is processed by grinding point classification to remove redundant points located outside the surface boundary.

[0012] Based on the set of grinding points after removing redundant points and the model parameters of the wind turbine blade, the final robot grinding trajectory pose is generated, and the grinding trajectory planning of the wind turbine blade is completed.

[0013] In some alternative embodiments, the directed bounding box method includes the bitetrahedral directed bounding box method.

[0014] In some optional embodiments, the compact oriented bounding box based on the wind turbine blade determines the initial tangent plane and tangent plane extension direction required by the isoplanar method, including:

[0015] Determine the longest axis of the compact oriented bounding box as the direction of tangential plane extension;

[0016] By drawing a ray in the opposite direction along the tangential plane extension direction, starting from the centroid of the compact oriented bounding box, and searching for the plane where the ray intersects the compact oriented bounding box, we obtain the initial tangential plane.

[0017] In some optional embodiments, the model parameters based on the wind turbine blade, the grinding parameters, the determined initial cutting plane and the cutting plane expansion direction, are used to obtain a preliminary grinding trajectory through the isoplanar method, including:

[0018] Using the roller diameter as the step size and the initial cutting plane as the starting surface, multiple processing cutting planes of equal size and parallel to the initial cutting plane are copied and generated along the expansion direction of the cutting plane to obtain a set of processing cutting planes whose occupied space area covers the space area occupied by the sub-surface set.

[0019] Based on the set of subsurfaces and the set of processing cutting planes, a preliminary grinding trajectory is obtained by taking the intersecting curves.

[0020] In some optional embodiments, the process of obtaining a set of grinding points based on the obtained preliminary grinding trajectory and the grinding parameters through discretization includes:

[0021] Based on the grinding feed rate v feed The control cycle of the grinding robot determines the chord length L between adjacent grinding points;

[0022] Based on the curve of the initial grinding trajectory, through second-order Taylor expansion and approximation, the iterative expression of the curve parameters corresponding to the grinding point is obtained as follows:

[0023]

[0024] Where C(u) represents the parameter representation of the initial grinding trajectory curve, and u represents the parameter of the trajectory curve. i Indicates t i The curve parameters corresponding to the grinding point at time t, ||·|| represents the modulus operation of the vector;

[0025] Based on the curve of the initial grinding trajectory, the determined chord length, and the iterative expression of the curve parameters corresponding to the grinding points, the curve parameters corresponding to each grinding point are recursively calculated and then substituted into the curve expression C(u) to obtain the set of grinding points.

[0026] In some optional embodiments, the step of removing redundant points located outside the surface boundary in the grinding point set through grinding point classification includes performing the following classification judgment operation on each grinding point in the grinding point set:

[0027] Starting from the grinding point P to be classified, and moving towards the subsurface S corresponding to grinding point P... i The center of mass P c Emit a ray R;

[0028] Obtain the relationship between ray R and subsurface S i Find all intersections and make a judgment:

[0029] If ray R and subsurface S i The number of intersection points is 0, or the ray R intersects with the subsurface S. i If none of the intersection points coincide with the grinding point P, then the grinding point P is determined to be on the subsurface S. i Externally, there are redundant points, and these redundant points are removed.

[0030] If there exists a ray R and a subsurface S i intersection point P c And P c =P, then the grinding point P is determined to be on the subsurface S. i Above, retain the grinding point P.

[0031] In some optional embodiments, generating the final robot grinding trajectory pose based on the grinding point set after removing redundant points and the model parameters of the wind turbine blade includes:

[0032] Based on the position of each grinding point and the characteristics of the surface it is located on, the robot's posture at each grinding point is deduced, and the robot's grinding trajectory pose is initially determined.

[0033] The starting and ending points of the robot's grinding trajectory pose corresponding to each trajectory are extended a certain distance to the outside of the wind turbine blade to generate external jump points.

[0034] Along the tangential plane expansion direction, connecting each trajectory in a zigzag sequence generates corresponding tool jump paths between adjacent external jump points, resulting in a complete grinding trajectory; on the tool jump path, according to the jump speed v jump move.

[0035] Secondly, embodiments of the present invention also provide an electronic device, including a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, it implements the method described in any embodiment of this specification.

[0036] Thirdly, embodiments of the present invention also provide a computer-readable storage medium having a computer program stored thereon, which, when executed in a computer, causes the computer to perform the methods described in any embodiment of this specification.

[0037] Fourthly, embodiments of the present invention also provide a method for grinding wind turbine blades, comprising:

[0038] The grinding trajectory planning method for wind turbine blades as described in any embodiment of this specification is used to perform grinding trajectory planning.

[0039] The planned grinding trajectory is output to the grinding robot so that the grinding robot can grind the wind turbine blades according to the planned grinding trajectory.

[0040] This invention provides a method, electronic device, and storage medium for planning the grinding trajectory of wind turbine blades, enabling efficient and automated planning of grinding trajectories. This invention eliminates the need for engineers' experience, allowing for rapid and automated planning of reasonable grinding trajectories for new wind turbine blade structures, and exhibits strong robustness, thus facilitating automated grinding of wind turbine blades.

[0041] This invention also provides a method for grinding wind turbine blades, which can automate the grinding of wind turbine blades, effectively reduce the manpower and time costs required for grinding wind turbine blades, and improve the efficiency and automation of the wind turbine blade production process. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a flowchart of a wind turbine blade grinding trajectory planning method provided in an embodiment of the present invention;

[0044] Figure 2 This is a schematic diagram of the distribution of sub-curved surfaces that need to be ground on one side of a wind turbine blade, provided by an embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram of a DiTO oriented bounding box generation step according to an embodiment of the present invention;

[0046] Figure 4 This is a schematic diagram illustrating the selection of the initial tangent plane and the tangent plane extension direction based on an embodiment of the present invention;

[0047] Figure 5 This is a schematic diagram of the distribution of redundant trajectory curve segments in one embodiment of the present invention;

[0048] Figure 6 yes Figure 5 Enlarged view of the dashed box area 'a' in the diagram;

[0049] Figure 7 yes Figure 5 Enlarged view of the dashed box area in Figure b;

[0050] Figure 8 This is a schematic diagram of a grinding point classification method provided in an embodiment of the present invention;

[0051] Figure 9 This is a schematic diagram of a jump path generation rule provided in an embodiment of the present invention;

[0052] Figure 10 This is a schematic diagram of the final robot polishing trajectory generated according to an embodiment of the present invention;

[0053] Figure 11 yes Figure 10 An enlarged view of the area within the dashed box (a) in the diagram. Detailed Implementation

[0054] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are some embodiments of the present invention, but not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0055] As mentioned earlier, the large size and complex structure of wind turbine blades restrict the realization of automated grinding, with a key challenge being the planning of a reasonable grinding path. Currently, the trajectory planning of grinding robots mainly relies on manual teaching. With the assistance of compliant devices, it is possible to grind simple surfaces, but it is difficult to plan the trajectory for large-sized, complex curved surface components. In view of this, this invention proposes a grinding trajectory planning method for wind turbine blades with high aspect ratio composite freeform surface structures.

[0056] The specific implementation of the above concept is described below.

[0057] Please refer to Figure 1 This invention provides a method for planning the grinding trajectory of wind turbine blades, the method comprising:

[0058] Step 100: Obtain the model parameters and grinding parameters of the wind turbine blade;

[0059] The model parameters for wind turbine blades include the 3D model data of the wind turbine blades and a set of subsurfaces consisting of all subsurfaces that need to be polished; such as Figure 2 The set of subsurfaces S shown NG ={S1,S2,S3,S4,S5,S6,S7} includes all sub-surfaces on one side of the wind turbine blade that need to be polished;

[0060] Grinding parameters include the roller diameter D of the grinding robot's grinding head. r Grinding feed speed v feed Setting tolerance ε set and jump speed v jump Grinding feed rate v feed This represents the moving speed and jump speed v of the grinding robot during the grinding process. jump This indicates the robot's movement speed when executing a jump path;

[0061] Step 102: Based on the 3D model data of the wind turbine blade, generate a compact directed bounding box (OBB) of the wind turbine blade using the directed bounding box method.

[0062] Step 104: Based on the compact oriented bounding box of the wind turbine blade, determine the initial tangent plane and the tangent plane extension direction required by the isoplanar method;

[0063] Step 106: Based on the model parameters, grinding parameters, and determined initial cutting plane and cutting plane expansion direction of the wind turbine blade, the preliminary grinding trajectory is obtained through the isoplanar method.

[0064] Step 108: Based on the obtained preliminary grinding trajectory and grinding parameters, the grinding point set is obtained through discretization.

[0065] Step 110: For the obtained grinding point set, remove redundant points located outside the surface boundary by classifying the grinding points.

[0066] Step 112: Based on the set of grinding points after removing redundant points, the model parameters of the wind turbine blade, and the grinding parameters, generate the final robot grinding trajectory pose and complete the wind turbine blade grinding trajectory planning.

[0067] The isoplanar method sets a set of parallel tangent planes intersecting the machined surface and uses the intersection lines of all parallel tangent planes with the machined surface as the grinding trajectory. The isoplanar method has strong robustness and can be used for composite surfaces, trimmed surfaces, and triangular mesh surfaces. However, the choice of the initial tangent plane and the direction of tangent plane extension has a significant impact on the quality of the grinding trajectory generated by the isoplanar method. Considering the high aspect ratio of wind turbine blades, there are usually relatively definite optimal initial tangent planes and tangent plane extension directions. To reduce reliance on engineer experience, the wind turbine blade grinding trajectory planning method provided in this embodiment of the invention obtains the model parameters and grinding parameters of the wind turbine blade, and uses the directed bounding box method combined with the isoplanar method to automatically find suitable initial tangent planes and tangent plane extension directions for the wind turbine blade to be ground, efficiently, reasonably, and automatically obtaining the preliminary grinding trajectory.

[0068] Considering that the initial grinding trajectory is a curve, in order to obtain a set of grinding trajectory points suitable for the work of the grinding robot, this embodiment of the invention refers to the grinding process requirements in the grinding parameters and discretizes the obtained initial grinding trajectory curve to obtain a set of grinding points.

[0069] Considering that wind turbine blades are composite freeform surface structures, there may be redundant trajectories in the preliminary grinding trajectory obtained by the isoplanar method. In this embodiment of the invention, after discretization, a redundancy removal process is performed, which transforms the problem of removing redundant trajectories into a grinding point classification problem. Redundant points that exceed the corresponding surface range in the grinding point set are removed to generate the final robot grinding trajectory pose.

[0070] This invention eliminates the need for manual selection of appropriate initial cutting planes and cutting plane extension directions. It can quickly and automatically plan reasonable grinding trajectories for new wind turbine blade structural components, and has strong robustness. It can replace manual teaching to complete the planning of grinding trajectories for wind turbine blades, thereby effectively reducing labor and time costs and improving the efficiency and automation of the wind turbine blade production process.

[0071] The following description Figure 1 The execution method for each step is shown.

[0072] For step 100, "Obtain the model parameters of the wind turbine blade", the 3D model data of the wind turbine blade can be obtained from the structural component CAD model, which can be created or directly imported.

[0073] Regarding step 102, "Based on the 3D model data of the wind turbine blade, generate a compact directed bounding box of the wind turbine blade using the directed bounding box method," the directed bounding box method includes the double tetrahedral directed bounding box method.

[0074] Wind turbine blades are composite freeform surface structures with high aspect ratios. Although the surface area to be ground is large, to meet aerodynamic requirements, there are no abrupt changes in local shape on the surface of wind turbine blades, resulting in strong consistency. Therefore, this invention proposes to use the double tetrahedral oriented bounding box (DiTO) method to generate compact oriented bounding boxes for wind turbine blades.

[0075] The DiTO method selects a small, fixed number of peripheral vertices from the input model, constructs a representative ditetrahedron using these vertices, and then derives the centroid, principal orientation, and projected length of the compact OBB from the edges of the ditetrahedron. For illustration, this invention uses a set of points in two-dimensional space. For example, the DiTO method is used to find a set of points. A compact OBB. For example... Figure 3 As shown, the DiTO method can be broken down into the following four steps:

[0076] 1. Selection of outer vertices: First, select the set The vertices in the projection onto N a The projector is assigned a specified projection axis, and then the minimum and maximum points of each axis are selected (i.e., the points with the minimum and maximum parameters corresponding to the projection of the current axis). The selection of the projection axis is related to the selected operator. To enable uniform sampling in the region where the model is located and to accelerate subsequent calculations, this invention adds additional projection axes formed by connecting the vertices of the boundary of each freeform surface of the model, based on the standard axis of the DiTO-14 operator provided by the conventional DiTO method, forming N. a projection axes, N a A single projection axis can generate a 2N a The set of outer points consisting of outer vertices

[0077] 2. Tetrahedron Construction: Using the Set of Outer Points The two vertices furthest apart in the triangle are used as one side of the triangle, and the vertex furthest from that side is used as the third vertex to generate a triangle. Using this triangle as the base triangle, two more connected tetrahedrons are created using the point furthest from the triangle plane, forming a ditetrahedron.

[0078] 3. Selection of the optimal principal orientation axis: Iterate through all seven faces of the bitetrahedron, use the local reference frames corresponding to all triangles as candidate axes for closely fitting the OBB to generate the corresponding OBB, and select the orientation axis of the OBB with the smallest surface area as the optimal principal orientation axis.

[0079] 4. Determining the projection length: [This involves] determining the point set. Project onto the principal direction axis determined in the previous step, and use the maximum projection distance of each axis as the projection length of OBB in the three principal directions.

[0080] Compared to Principal Component Analysis (PCA), the most commonly used method for generating OBBs, the DiTO method does not require all point cloud data of the model and generates more compact OBBs. Using the above embodiment, a compact oriented bounding box of the wind turbine blade can be quickly found with high computational efficiency, and the results are closer to the wind turbine blade, which is beneficial for subsequently determining a more favorable initial tangent plane and tangent plane extension direction.

[0081] Regarding step 104, "Based on the compact oriented bounding box of the wind turbine blade, determine the initial tangent plane and tangent plane extension direction required by the isoplanar method," it includes:

[0082] Determine the longest axis of the compact oriented bounding box as the direction of tangential plane extension;

[0083] By drawing a ray in the opposite direction along the tangential plane extension direction, starting from the centroid of the compact oriented bounding box, and searching for the plane where the ray intersects the compact oriented bounding box, we obtain the initial tangential plane.

[0084] like Figure 4 As shown, the three principal directions (X, Y, Z) of the OBB of the wind turbine blade generated by the DiTO method are... obb Y obb and Z obb In the model, the longest axis direction coincides with the longitudinal growth direction of the blade. Therefore, this invention selects the longest axis as the tangential plane extension direction D of the isoplanar method. extend This also facilitates the polishing of the blade surface. Taking the OBB centroid O of the wind turbine blade as the starting point and the direction opposite to the longest axis as the direction, draw a ray R... longest Then, by traversing the six planes of OBB, we obtain the result related to ray R. longest The intersecting planes are taken as the initial tangent plane C0.

[0085] The above embodiments fully consider the characteristics of high aspect ratio of wind turbine blades and the production experience of manually grinding wind turbine blades by grinding around the longitudinal growth direction of the blade, and formulate an automated trajectory planning scheme that maintains production quality.

[0086] Regarding step 106, "Based on the model parameters of the wind turbine blade, grinding parameters, the determined initial tangential plane and the tangential plane extension direction, the preliminary grinding trajectory is obtained through the isoplanar method," it includes:

[0087] With roller diameter D r Let C0 be the initial tangent plane and D be the step size. extendMultiple machining cutting planes of the same size and parallel to the initial cutting plane C0 are generated by copying, resulting in a set S of machining cutting planes covering the spatial region of the subsurface set. TP In other words, generate enough cutting planes to cover all areas to be polished;

[0088] Based on the subsurface set S NG and processing cutting plane set S TP The initial polishing trajectory is obtained by taking the intersecting curves.

[0089] For wind turbine blades, the set of subsurfaces S to be polished NG Each surface is a non-uniform rational B-spline (NURBS) surface. The parametric expression S(u,v) of the NURBS surface is Equation (1), and the plane equation expression is Equation (2). Obtaining the intersecting curve is the process of finding the common solution of Equation (1) and Equation (2).

[0090]

[0091] Ax + By + Cz + D = 0 (2)

[0092] Where u and v are parameters of the freeform surface, and x, y, and z are differentiable functions of parameters u and v. A, B, C, and D are constants, and A, B, and C are not simultaneously zero.

[0093] Using the above implementation method, an initial grinding trajectory suitable for grinding requirements can be quickly found. However, the initial grinding trajectory curve contains segments that extend beyond the surface boundary and overlap with trajectories generated by other surfaces, resulting in redundant trajectory curves, such as... Figures 5 to 7 As shown, Figure 6 yes Figure 5 The enlarged diagram of the dashed box area 'a' shows that when two curve segments overlap, redundant trajectories may appear. Figure 7 yes Figure 5 The enlarged schematic diagram of the dashed box area in Figure b shows that redundant trajectories may also appear when there are gaps in the wind turbine blade structure. The reason for this phenomenon is that each sub-surface on the surface of the wind turbine blade is constrained by the boundary contour, but the parameter representation of the surface in formula (1) cannot include boundary information. Therefore, post-processing is required to eliminate these redundant trajectories. However, it is difficult to determine whether a certain part of the curve is within the surface boundary. Therefore, this invention simplifies the problem by performing redundancy removal processing after discretization, transforming the problem of removing redundant trajectories into a grinding point classification problem, thereby reducing the amount of computation and lowering the difficulty of redundancy removal.

[0094] Regarding step 108, "Based on the obtained preliminary grinding trajectory and grinding parameters, a set of grinding points is obtained through discretization processing," it includes:

[0095] Based on the obtained preliminary grinding trajectory and grinding parameters, the preliminary grinding trajectory is discretized using the equal chord length method to obtain the grinding point set.

[0096] The end effector of a grinding robot moves continuously along the grinding trajectory by chaining the movements of adjacent trajectory points. Therefore, after generating the initial grinding trajectory, the trajectory curve needs to be discretized into grinding points. Ideally, the grinding points should make the robot's actual motion trajectory as close as possible to the intersecting surface contour lines obtained by the isoplanar method. In principle, the more grinding points, the higher the accuracy of the grinding robot's motion trajectory in tracking the intersecting contour lines. However, if the grinding points are too dense, it will increase the system load, and the grinding robot is prone to shaking or oscillation during actual operation.

[0097] The Euclidean distance between adjacent points on a single grinding path is called the path step size l. i The chord height error δ between the two points i This describes the accuracy of the actual grinding robot's motion trajectory and intersecting contour lines. Under the premise that the control chord height error is less than the set tolerance, the control trajectory step size l is... i The number and location of discrete grinding points can be reasonably allocated. In CNC machining, the commonly used method for controlling the step distance of the trajectory is the constant chord height error method, which can ensure that the chord height error of the grinding trajectory is constant. At the same time, based on the chord height error, the step distance of adjacent grinding points can be obtained, thus obtaining the grinding point set. However, the constant chord height error method cannot control the step distance of adjacent grinding points to be constant. For the robot grinding process, if the communication cycle is constant, the change in step distance will cause the feed speed of the end grinding tool to change, resulting in inconsistent surface processing quality of wind turbine blades.

[0098] To maintain a constant feed rate in the robot's grinding process, this invention employs the constant chord length method to control the step size. To ensure trajectory tracking accuracy, the maximum chord height error δ caused by the discrete grinding point set obtained using the constant chord length method is minimized. max It should not exceed the set tolerance ε set If the maximum chord height error δ max Greater than the set tolerance ε set This indicates that the chord length L setting is too large and should be reduced. The traditional equal chord length method maintains a constant Euclidean distance between adjacent trajectory points. It typically involves drawing a circle with the center trajectory point as the center and the chord length L as the radius. The intersection of this circle and the trajectory curve in the trajectory feed direction is the next grinding point. Repeating this process yields a discrete set of grinding points.

[0099] By adopting the above embodiments, the variation in the feed speed of the end-grinding tool can be effectively reduced, ensuring the processing quality of the wind turbine blade surface by the grinding robot.

[0100] The traditional equal chord length method requires solving for the intersection of the circle equation and the trajectory curve equation, resulting in low computational efficiency and a tendency to fail to find intersections at the curve ends, thus reducing path coverage. Therefore, this invention proposes an improved equal chord length method based on Taylor quadratic expansion to enhance the computational efficiency of the equal chord length method for discretizing grinding trajectories.

[0101] The grinding trajectory curve can be described by the NURBS curve C(u). For the curve C(u) in parametric form, a Taylor second expansion can be used to discretize the curve, transforming the parameter u into a function of time t, expressed as:

[0102]

[0103] Where, v(t) i ) represents t i Constantly refine the feed rate, a(t) i ) represents t i The acceleration of constant refinement, u i Indicates t i The curve parameters at a given time point are the curve parameters corresponding to a specific grinding point. Since the grinding speed is low and the grinding feed rate is constant during processing, the influence of the acceleration term can be ignored. Furthermore, because the distance between adjacent grinding points is very small, the feed rate along the grinding curve can be approximated as the linear velocity between the two grinding points, which has the following relationship with the chord length L:

[0104] L=v(t i )(t i+1 -t i (4)

[0105] Combining equations (3) and (4) yields the iterative expression for parameter u, which is also the iterative expression for the curve parameter corresponding to the grinding point. The curve parameter u corresponding to the next grinding point is obtained through the chord length L. i+1 Then, substituting this into the trajectory curve expression, we obtain the grinding point.

[0106] Preferably, step 108, "based on the obtained preliminary grinding trajectory and grinding parameters, a set of grinding points is obtained through discretization processing," includes:

[0107] Based on the grinding feed rate v feed The control cycle of the grinding robot determines the chord length L between adjacent grinding points;

[0108] Based on the curve of the initial grinding trajectory, through second-order Taylor expansion and approximation, the iterative expression of the curve parameters corresponding to the grinding point is obtained as follows:

[0109]

[0110] Where C(u) represents the parameter representation of the initial grinding trajectory curve, and u represents the parameter of the trajectory curve. i Indicates t i The curve parameters corresponding to the grinding point at time t, ||·|| represents the modulus operation of the vector;

[0111] Based on the curve of the initial grinding trajectory, the determined chord length, and the iterative expression of the curve parameters corresponding to the grinding points, the curve parameters corresponding to each grinding point are recursively calculated and then substituted into the curve expression C(u) to obtain the set of grinding points.

[0112] The above embodiment uses Taylor quadratic expansion to approximate the grinding trajectory curve and derives the iterative relationship between the curve parameters corresponding to the grinding point and the chord length. Compared with the traditional equal chord length method, it not only improves the computational efficiency and reduces the amount of computation, but also ensures the quality of the discrete grinding point, that is, it ensures that the grinding robot can complete high-quality grinding work with a relatively constant grinding feed speed.

[0113] like Figure 8 As shown, for step 110, "removing redundant points located outside the surface boundary in the grinding point set through grinding point classification processing" includes performing the following classification judgment operation on each grinding point in the grinding point set:

[0114] Starting from the grinding point P to be classified, and moving towards the subsurface S corresponding to grinding point P... i The center of mass P c Emit a ray R;

[0115] Obtain the relationship between ray R and subsurface S i All intersection points P int And make a judgment:

[0116] If ray R and subsurface S i The number of intersection points is 0, or the ray R intersects with the subsurface S. i If none of the intersection points coincide with the grinding point P, then the grinding point P is determined to be on the subsurface S. i Externally, there are redundant points, and these redundant points are removed.

[0117] If there exists a ray R and a subsurface S i intersection point P c And P c =P, then the grinding point P is determined to be on the subsurface S. i Above, retain the grinding point P.

[0118] Post-processing of the grinding trajectory includes redundant trajectory elimination, tool direction generation, and tool jump path generation. After trajectory discretization, the problem of removing redundant trajectories is transformed into the problem of filtering redundant points. Eliminating redundant grinding points is essentially a classification problem, i.e., how to classify points as inside / outside the surface boundary. This invention proposes a point / surface classification method to classify points by determining the number and position of intersections between rays and surfaces. The above embodiments address the problem of redundant trajectories in composite freeform surface grinding trajectories that partially extend beyond the surface boundary. A point / surface classification algorithm is proposed to classify grinding points as inside or outside the surface boundary based on the number and position of intersections between rays and surfaces, thereby filtering out redundant grinding points outside the boundary. This can automatically and quickly filter out redundant points in the grinding point set, preventing redundant trajectories from interfering with the normal operation of the grinding robot.

[0119] Regarding step 112, "Generating the final robot grinding trajectory pose based on the grinding point set after removing redundant points and the model parameters of the wind turbine blade," it includes:

[0120] Based on the position of each grinding point and the characteristics of the surface it is located on, the robot's posture at each grinding point is deduced, and the robot's grinding trajectory pose is initially determined, i.e., tool orientation generation.

[0121] The starting and ending points of the robot's grinding trajectory pose corresponding to each trajectory are extended a certain distance to the outside of the wind turbine blade to generate external jump points.

[0122] Along the tangential plane expansion direction, connecting each trajectory in a zigzag sequence generates corresponding tool jump paths between adjacent external jump points, resulting in a complete grinding trajectory; on the tool jump path, according to the jump speed v jump move.

[0123] To control the optimal contact posture between the grinding tool and the wind turbine blade surface, ensuring that the normal contact force is correctly applied to the surface and generated in the tool direction, it is necessary to control the grinding tool support direction Z at the grinding point. tool Aligning with the normal direction of the blade surface, and simultaneously grinding the tool axis direction X. tool Consistent with the tangential direction of the blade surface parameter u, the posture of the robot grinding tool follows equation (6).

[0124]

[0125] N(u,v)=S u (u,v)×S v (u,v) (7)

[0126] Among them, S u (u,v) and Sv (u,v) is the tangent vector of the surface S(u,v) at the grinding point P(u,v), S u (u,v) is the feed vector, S v (u,v) is the tangent vector of parameter v. The normal vector at the grinding point P(u,v) is shown in equation (7).

[0127] To obtain the normal vector N(u,v) and feed vector S of the surface at the grinding point P(u,v). u To obtain the parameters (u,v) of the grinding point P(x,y,z) on the surface S(u,v), we need to inversely calculate the parameters (u,v) of the grinding point P(x,y,z) in the surface S(u,v). For this purpose, we define a vector function r(u,v) from S(u,v) to a certain position P, with the expression:

[0128] r(u,v)=S(u,v)-P(x,y,z) (8) and two scalar equations, expressed as:

[0129]

[0130] The parametric coordinates (u, v) of the grinding point P on the surface can be obtained by solving equation (11) using the Newton iteration method. The convergence condition is shown in equation (10):

[0131]

[0132] In equation (10), Δu and Δv represent the iteration step size of parameters u and v, respectively. i and v i This represents the parameter value obtained in the i-th Newton iteration. ε1 and ε2 serve as two tolerances for judging convergence, used to measure whether the Euclidean distance and cosine value are 0, respectively.

[0133] Figure 9 The rules for generating the tool skip path are described. Since the grinding tool's rollers are similar to those of a belt grinder, during lateral movement, the grinding tool cannot move flush against the wind turbine blade surface. Instead, the starting and ending points of the grinding trajectory need to be extended a certain distance outwards along the surface normal vector N(u,v) of the wind turbine blade, and then the tool skip path is generated in a zigzag pattern. The specific outward extension distance can be set according to actual needs, such as 50mm.

[0134] like Figure 10 and Figure 11 As shown, a complete grinding trajectory can be obtained, which is used to instruct the grinding robot to perform automated grinding.

[0135] This invention also provides a method for grinding wind turbine blades, comprising:

[0136] A method for planning the grinding trajectory of a wind turbine blade is used in any embodiment of the present invention to plan the grinding trajectory.

[0137] The planned grinding trajectory is output to the grinding robot so that the grinding robot can grind the wind turbine blades according to the planned grinding trajectory.

[0138] The above-mentioned wind turbine blade grinding method can replace manual grinding, realize automated grinding of wind turbine blade surface, save labor and time costs, and improve production efficiency.

[0139] This invention also provides an electronic device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, it implements a wind turbine blade grinding trajectory planning method according to any embodiment of this invention.

[0140] This invention also provides a computer-readable storage medium storing a computer program. When executed by a processor, the computer program causes the processor to perform a wind turbine blade grinding trajectory planning method according to any embodiment of this invention.

[0141] Specifically, a system or apparatus equipped with a storage medium may be provided, on which software program code implementing the functions of any of the embodiments described above is stored, and the computer (or CPU or MPU) of the system or apparatus may read and execute the program code stored in the storage medium.

[0142] In this case, the program code read from the storage medium can itself implement the function of any of the above embodiments, and therefore the program code and the storage medium storing the program code constitute part of the present invention.

[0143] Examples of storage media used to provide program code include floppy disks, hard disks, magneto-optical disks, optical disks (such as CD-ROM, CD-R, CD-RW, DVD-ROM, DVD-RAM, DVD-RW, DVD+RW), magnetic tapes, non-volatile memory cards, and ROMs. Alternatively, program code can be downloaded from a server computer via a communication network.

[0144] Furthermore, it should be clear that not only can the program code read by the computer be executed, but also the operating system or other components operating on the computer can be instructed based on the program code to perform some or all of the actual operations, thereby realizing the function of any of the embodiments described above.

[0145] Furthermore, it is understood that the program code read from the storage medium is written to the memory set in the expansion board inserted into the computer or to the memory set in the expansion module connected to the computer. Then, based on the instructions of the program code, the CPU or other components installed on the expansion board or expansion module execute some and all of the actual operations, thereby realizing the function of any of the above embodiments.

[0146] In summary, this invention provides a method for grinding wind turbine blades and a trajectory planning method applicable to composite freeform surface structures with high aspect ratios. Verification in the application scenario of grinding wind turbine blades demonstrates the feasibility and high efficiency of this method. This invention integrates grinding trajectory planning, offline programming, and simulation, reducing the cost of manual teaching and planning of grinding trajectories, and improving production efficiency and automation. Furthermore, the method provided by this invention has strong versatility and can also be used for grinding trajectory planning of large composite freeform surface structures with high aspect ratios, such as high-speed railway carriages and aerospace components.

[0147] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0148] Those skilled in the art will understand that all or part of the steps of the above method embodiments can be implemented by hardware related to program instructions. The aforementioned program can be stored in a computer-readable storage medium. When the program is executed, it performs the steps of the above method embodiments. The aforementioned storage medium includes various media that can store program code, such as ROM, RAM, magnetic disk, or optical disk.

[0149] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for planning the grinding trajectory of wind turbine blades, characterized in that, include: Obtain the model parameters and grinding parameters of the wind turbine blade; wherein, the model parameters include the 3D model data of the wind turbine blade and a set of subsurfaces consisting of all subsurfaces that need to be ground, and the grinding parameters include the roller diameter of the grinding head. Grinding feed speed Setting tolerances and jump speed ; Based on the 3D model data of the wind turbine blade, a compact oriented bounding box of the wind turbine blade is generated using the oriented bounding box method. Based on the compact oriented bounding box of the wind turbine blade, the initial tangent plane and the tangent plane extension direction required by the isoplanar method are determined; Based on the model parameters of the wind turbine blade, the grinding parameters, the determined initial cutting plane and the direction of cutting plane expansion, the preliminary grinding trajectory is obtained by the isoplanar method. Based on the obtained preliminary grinding trajectory and the grinding parameters, a set of grinding points is obtained through discretization. The obtained set of grinding points is processed by grinding point classification to remove redundant points located outside the surface boundary. Based on the set of grinding points after removing redundant points and the model parameters of the wind turbine blade, the final robot grinding trajectory pose is generated, and the wind turbine blade grinding trajectory planning is completed. The step of classifying grinding points to remove redundant points located outside the surface boundary includes performing the following classification judgment operation on each grinding point in the grinding point set: Grinding points to be classified Starting from the grinding point Corresponding subsurface center of mass Emit a ray ; Acquiring rays and sub-surface Find all intersections and make a judgment: If the ray and sub-surface The number of intersection points is 0, or the ray and sub-surface All intersections are not at the grinding point If they coincide, then the grinding point is determined. On the subsurface Externally, there are redundant points, and these redundant points are removed. If rays exist and sub-surface intersection and Then determine the grinding point. On the subsurface Above, retain the grinding point. .

2. The method according to claim 1, characterized in that, The directed bounding box method includes the bitetrahedral directed bounding box method.

3. The method according to claim 1, characterized in that, The compact oriented bounding box based on wind turbine blades determines the initial tangent plane and tangent plane extension direction required by the isoplanar method, including: Determine the longest axis of the compact oriented bounding box as the direction of tangential plane extension; By drawing a ray in the opposite direction along the tangential plane extension direction, starting from the centroid of the compact oriented bounding box, and searching for the plane where the ray intersects the compact oriented bounding box, we obtain the initial tangential plane.

4. The method according to claim 1, characterized in that, The model parameters based on the wind turbine blade, the grinding parameters, the determined initial tangential plane and the tangential plane expansion direction, are used to obtain the preliminary grinding trajectory through the isoplanar method, including: Using the roller diameter as the step size and the initial cutting plane as the starting surface, multiple processing cutting planes of equal size and parallel to the initial cutting plane are copied and generated along the expansion direction of the cutting plane to obtain a set of processing cutting planes whose occupied space area covers the space area occupied by the sub-surface set. Based on the set of subsurfaces and the set of processing cutting planes, a preliminary grinding trajectory is obtained by taking the intersecting curves.

5. The method according to claim 1, characterized in that, Based on the obtained preliminary grinding trajectory and the grinding parameters, a set of grinding points is obtained through discretization, including: Based on the grinding feed rate The control cycle of the grinding robot determines the chord length between adjacent grinding points. L ; Based on the curve of the initial grinding trajectory, through second-order Taylor expansion and approximation, the iterative expression of the curve parameters corresponding to the grinding point is obtained as follows: in, This is a parameter representation for the initial polishing trajectory curve. u Parameters representing the trajectory curve, express The curve parameters corresponding to the grinding point at time t, ||·|| represents the modulus operation of the vector; Based on the initial grinding trajectory curve, the determined chord length, and the iterative expression of the curve parameters corresponding to the grinding points, the curve parameters corresponding to each grinding point are recursively calculated, and then substituted into the curve expression. In this process, the set of grinding points is obtained.

6. The method according to claim 1, characterized in that, The final robot grinding trajectory pose is generated based on the set of grinding points after removing redundant points and the model parameters of the wind turbine blade, including: Based on the position of each grinding point and the characteristics of the surface it is located on, the robot's posture at each grinding point is deduced, and the robot's grinding trajectory pose is initially determined. The starting and ending points of the robot's grinding trajectory pose corresponding to each trajectory are extended a certain distance to the outside of the wind turbine blade to generate external jump points. Along the tangential plane expansion direction, connecting each trajectory in a zigzag sequence generates corresponding tool jump paths between adjacent external jump points, resulting in a complete grinding trajectory; on the tool jump path, according to the jump speed... move.

7. An electronic device comprising a memory and a processor, wherein the memory stores a computer program, characterized in that, When the processor executes the computer program, it implements the method as described in any one of claims 1-6.

8. A storage medium having a computer program stored thereon, characterized in that, When the computer program is executed in the computer, it causes the computer to perform the method of any one of claims 1-6.

9. A method for grinding wind turbine blades, characterized in that, include: The grinding trajectory planning method for wind turbine blades as described in any one of claims 1-6 is used to perform grinding trajectory planning. The planned grinding trajectory is output to the grinding robot so that the grinding robot can grind the wind turbine blades according to the planned grinding trajectory.

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