Method for draping a flat material

Abstract

Method for draping a flat material (106, 304) on a deposit surface using a draping model and an effector (300, 400, 500) with a plurality of active modules (302, 406) which can each be moved relative to one another with a degree of freedom f=6 and can be activated and deactivated, characterized in that reference points (102) of the material (106, 304) are defined, a transformation matrix between a receiving geometry (104) and a deposit geometry (108) is determined for the reference points (102), and the effector (300, 400, 500) with its active modules (302, 406) is controlled taking into account the transformation matrix.

Description

[0001] The invention relates to a method for draping a flat material on a support surface using a draping model and an effector with several active modules that can be moved relative to each other, activated and deactivated, each with a degree of freedom f=6

[0002] The publication "GERNGROSS, Tobias; NIEBERL, Dorothea. Automated manufacturing of large, three-dimensional CFRP parts from dry textiles. CEAS Aeronautical Journal, 2016, Vol. 7, No. 2, pp. 241-257." concerns the production of large parts made of carbon fiber reinforced plastic in the aerospace industry and addresses the process chain from the dry textile through production-integrated quality assurance to the cured component. To convert manual manufacturing methods into automated processes, the publication "GERNGROSS, Tobias; NIEBERL, Dorothea. Automated manufacturing of large, three-dimensional CFRP parts from dry textiles. CEAS Aeronautical Journal, 2016, Vol. 7, No. 2, pp. 241-257." It was suggested that sensors should be integrated into the production process for quality assurance purposes and that the position and draping of the cut pieces should be determined using laser light section technology and fiber angle measurement.This enables the identification of process parameters and potential deviations in the production chain. Corrections can be made early on, which represents a significant advantage over the previous inspection of the finished component. Insights are provided into the development of the gripper system, the quality assurance measures, and the semi-automatic vacuum packaging, including their current maturity level. Draping woven fabrics: Progressive draping model

[0003] The publication "SHARMA, SB; SUTCLIFFE, MPF Draping of woven fabrics: Progressive drape model. Plastics, rubber and composites, 2003, Vol. 32, No. 2, pp. 57-64." concerns a progressive drape model for draping woven fabrics. To predict the drape of fabrics on irregular surfaces, the publication "SHARMA, SB; SUTCLIFFE, MPF Draping of woven fabrics: Progressive drape model. Plastics, rubber and composites, 2003, Vol. 32, No. 2, pp. 57-64." proposes a membrane tension-based model. The proposed model for progressive drape represents a middle ground between kinematic drape models based on pure shear as the main mechanism and comprehensive FE-based drape models that consider the interaction of the fabric with the tool and the processing environment.

[0004] From the document DE 10 2015 107 394 A1 a method is known for picking up, handling and / or depositing textile structures, in particular during the production of fiber composite components, wherein a device with a manipulator, in particular with an industrial robot, and an effector with a base module, several active modules that can be displaced in a controlled manner relative to the base module and passively adaptive actuation modules for the controlled displacement of the active modules is used and the active modules are displaced in a coordinated manner in order to pick up, handle and / or deposit textile structures.

[0005] From DE 10 2013 202 571 A1 an end effector is known for a manipulator, comprising a plurality of active modules for interacting with workpieces and a plurality of actuator modules for moving the active modules, wherein the active modules are each movable relative to one another in six Cartesian degrees of freedom with the aid of the actuator modules and with the aid of the active modules workpieces can be accommodated in a manner adapted to predetermined holding sections and can be draped spatially freely, in which a plurality of actuator modules form a kinematically redundant actuator arm.

[0006] DE 10 2013 208 778 A1 discloses a device for picking up, handling, and / or depositing textile structures with two angularly intersected fiber systems, particularly during the production of fiber composite components. The device comprises a lattice structure with a first rod system with first parallel rods and a second rod system with second parallel rods. The first rod system and the second rod system are arranged at an angle to each other and can be displaced in a rhombus-like or parallelogram-like manner. Retaining elements for holding a textile structure can be arranged on the lattice structure in a variably positionable manner. The retaining elements can each be positioned to suit a textile structure.

[0007] From DE 10 2016 103 761 A1, an active module is known for picking up, handling and / or depositing workpieces, wherein the active module has a holding section for picking up and / or holding a workpiece and an optical sensor section with at least one light source, at least one image sensor and / or an electrical control device, wherein the sensor section is structurally integrated into the holding section.

[0008] The invention is based on the object of structurally and / or functionally improving a method mentioned at the outset.

[0009] The object is achieved by a method having the features of claim 1. Particularly preferred developments of the method according to the invention are the subject of the subclaims.

[0010] The material can be pliable. The material can be inherently stiff. The material can be homogeneous. The material can be inhomogeneous. The material can have fibers. The material can have at least two interlaced fiber systems. The material can be a textile. The material can be a ready-made item. The material can be a cut piece. The material can be a woven, warp-knitted, braided, stitch-bonded fabric, or tape. The material can have organic fibers such as aramid fibers, carbon fibers, polyester fibers, nylon fibers, polyethylene fibers, Plexiglas fibers, and / or inorganic fibers such as basalt fibers, boron fibers, glass fibers, ceramic fibers, or silica fibers. The fibers can have filaments. The filaments can be combined to form a roving. The material can have a first fiber system and a second fiber system. The fibers of a fiber system can be at least approximately co-oriented.The fibers of a fiber system can be at least approximately parallel to each other. The material can be a semi-finished fiber product. The material can be a dry semi-finished fiber product. The material can be a pre-impregnated semi-finished product. The material can be a prepreg.

[0011] The material can be used to manufacture a fiber composite component. The material can be used for embedding in a matrix component. The matrix component can have a thermoplastic matrix. The matrix component can have polyetheretherketone (PEEK), polyphenylene sulfide (PPS), polysulfone (PSU), polyetherimide (PEI), and / or polytetrafluoroethylene (PTFE). The matrix component can have a thermosetting matrix. The matrix component can have epoxy resin (EP), unsaturated polyester resin (UP), vinyl ester resin (VE), phenol-formaldehyde resin (PF), diallyl phthalate resin (DAP), methacrylate resin (MMA), polyurethane (PUR), and / or amino resins, such as melamine resin (MF / MP) or urea resin (UF). The matrix component can have benzoxaines.

[0012] The fiber composite component can be manufactured using a lamination process. The fiber composite component can be manufactured using a resin injection process. The fiber composite component can be manufactured using a vacuum infusion process. The fiber composite component can be manufactured using a transfer molding process, also known as resin transfer molding (RTM). The fiber composite component can be a vehicle component. The vehicle can be a land vehicle, motor vehicle, aircraft, watercraft, or spacecraft. The fiber composite component can be a consumer product component. The consumer product can be a sporting goods item. The fiber composite component can be a capital product component. The capital product can be a wind turbine. The capital product component can be a blade of a wind turbine.

[0013] Draping can involve picking up the material from a receiving surface, reshaping the material, and depositing it on a depositing surface. Draping can be used to adapt the material to the depositing surface. Draping can be used to represent predetermined fiber orientations. During draping, the material can be reshaped, stretched, and / or warped, at least in sections. Draping behavior can be influenced by material characteristics.

[0014] The receiving surface can be flat. The receiving surface can belong to a cutting device or to a storage area. Multiple pieces of material can be arranged on the receiving surface. The pieces of material can be stacked. The material can be picked up from the receiving surface or from a stack of material pieces. The storage area can be curved. The storage area can be curved multiple times and / or spatially. The storage area can be convex and / or concave. The storage area can be a surface of a forming tool. Material can already be arranged on the storage area. The material can be deposited on the storage area and / or on material already arranged on the storage area.

[0015] The draping model can be a mathematical model. The draping model can be an information technology model. The draping model can be a control engineering model. The draping model can be a computer program. The draping model can be used to simulate draping. Simulation can be used to analyze dynamic system behavior. In simulation, draping can be carried out using a model of the material and a model of the effector in order to gain insights into a real system and a real process sequence. In simulation, the real system and the real process sequence can be represented in an abstract manner. In simulation, in particular, the structure, function, and behavior of the system and the process sequence can be represented. Simulation can be parameterized with concrete values. Simulation results can be interpreted and transferred to the real system and the real process sequence.The simulation can be performed using a computer and a computer program. The draping model can be used to determine parameter values ​​for controlling a real effector. The draping model can include the transformation matrix.

[0016] The effector can be mounted on an industrial robot. The industrial robot can have a manipulator. The industrial robot can have an electrical control device. The control device can be used to control the industrial robot. The effector can be an end effector. The effector can have a connecting flange for connection to the industrial robot, in particular to the manipulator.

[0017] The effector can have an effector base. The active modules can each be movable relative to the effector base and / or relative to one another. The active modules can each be movable with a degree of freedom f=6. The active modules can each be displaced along each axis in a Cartesian coordinate system with three mutually perpendicular axes and can be rotated about each axis. The active modules can each be moved independently of the other active modules. The active modules can each be moved kinematically independently of one another. In this context, "kinematically independent" can mean that a movement of one active module has no kinematic influence on other active modules or that a movement of one active module can at least approximately compensate for a kinematic influence on other active modules.

[0018] The effector can have actuator modules for moving the active modules. The actuator modules can each be arranged between the base and an active module. The actuator modules can each be arranged between two active modules. The actuator modules can each have at least one drive. The drives can each be actuated electrically, mechanically, by an electric motor, magnetically, pneumatically, and / or hydraulically. The actuator modules can each have a gear mechanism. The actuator modules can also be referred to as individual kinematics. The effector can have flexible multi-axis kinematics.

[0019] The active modules can be used to pick up, hold, and / or deposit the material. The active modules can be used to hold the material in a slip-free manner. Each active module can have an active surface for establishing a releasable active pairing with the material. The active surfaces can each act mechanically, pneumatically, magnetically, electrostatically, and / or adhesively. The active modules can be designed as suction grippers or needle grippers. Activating / deactivating an active module can be understood as activating / deactivating an active surface. When the active module is activated, the material can be picked up and / or held. When the active module is deactivated, the material can be deposited.

[0020] The effector can have at least one effector arm. An effector arm can also be referred to as a manipulation arm. The at least one effector arm can have at least one active module and a plurality of actuators. An active module can be arranged at a free end of the at least one effector arm. Active modules and actuator modules of an effector arm can be arranged in a chain along an effector arm axis. The at least one effector arm can be arranged at the effector base.

[0021] The effector, the actuator modules, and / or the active modules can be controlled using an electrical control device. The control device of an industrial robot can be used to control the effector, the actuator modules, and / or the active modules. A separate control device can be used to control the effector, the actuator modules, and / or the active modules. The separate control device can be connected to a control device of an industrial robot for signal transmission.

[0022] Material reference points can be points on a material surface. Material reference points can be used to establish a releasable interaction with the active modules, especially the active surfaces, of the effector. The material reference points can be determined using the draping model and transferred to a real material.

[0023] The reference points can be defined for the receiving geometry and the storage geometry. The reference points for the receiving geometry and the reference points for the storage geometry can be linked. The transformation matrix can be used to link the reference points for the receiving geometry and the reference points for the storage geometry.

[0024] To determine the transformation matrix, trajectories of the reference points between the acquisition geometry and the placement geometry can be determined. A trajectory can be a time-dependent sequence of reference point positions. A trajectory can be represented as a time-dependent function. A trajectory can specify a reference point path using target positions of the reference points for a current time step and subsequent time steps. The subsequent time steps can be past and / or future time steps.

[0025] The reference points can each have a local coordinate system. The local coordinate systems can be Cartesian coordinate systems. The local coordinate systems can move translationally and / or rotationally with the reference points. To determine the transformation matrix, rotations of the local coordinate systems between the acquisition geometry and the deposit geometry can be determined. The rotations of the local coordinate systems can be described using trajectories. The trajectories can include time-dependent sequences of rotations of the local coordinate systems. The trajectories can specify rotation sequences of the local coordinate systems using target rotations of the local coordinate systems for a current time step and subsequent time steps. The subsequent time steps can be past and / or future time steps.

[0026] The draping model can have finite elements. The finite elements can have vertices. The vertices of the finite elements can also be referred to as nodes. The draping model can have nodes. The reference points can lie on nodes. A reference point can be defined for each node.

[0027] Material parameters can be considered. Material parameters can include fiber directions, fiber angles, stretching, warping, shearing, and / or material characteristics. Friction coefficients can be considered. Friction coefficients can be internal friction coefficients of the material. Friction coefficients can be friction coefficients between the material and a receiving surface and / or a depositing surface.

[0028] Draping can involve draping multiple pieces of material onto the support surface. A draping sequence can be determined. A draping sequence of the pieces of material can be determined. Draping can be simulated at least once. Draping can be simulated several times. Required draping forces can be determined. The magnitude of the draping forces can be determined. The direction of the draping forces can be determined. The direction of the draping forces can be determined vectorially.

[0029] Holding points for introducing draping forces into the material can be defined. Reference points and holding points can correspond to each other. Holding points can be reference points on a real material where the material is actually picked up and / or held. Reference points can be used in the draping model. Reference points can be defined as holding points. The material can be held at least approximately slip-free at the holding points during draping. One of the holding points can be defined as the starting point for controlling the active moduli.

[0030] In summary and in other words, the invention thus results, among other things, in a method for developing process strategies for the active draping of textile semi-finished products and their conversion into control data for production manipulators.

[0031] Automated draping can be achieved with the help of active draping by coupling the results of a draping simulation and flexible multi-axis kinematics. A draping simulation can be used in more detail, and additional calculations can be performed. These results can be used to control the flexible multi-axis kinematics. A displacement vector (trajectory) and a rotation of a local coordinate system of mesh nodes of a draping model can be determined between 2D and 3D based on the draping simulation. Vectors and rotations can together result in a transformation matrix. Required data can be obtained from the draping model. The required draping forces and their direction, which are introduced into a material via active surfaces, can be calculated to achieve reliable and wrinkle-free draping.Suitable points of application for minimal force and the best possible draping result can be determined. A chronological sequence of each point of application can be determined. Determined transformation matrices can be used to control an end effector and its respective individual kinematics. Relative movement between the effective surface (point of application to the material) and the semi-finished product can be deliberately prevented. Changes in points of application between a flat state (2D) and a draped state (3D), both in terms of their location and their orientation in space, can be calculated in the form of transformation matrices and used to control an end effector with manipulation arms. This can also be used to determine the forces required for shearing or draping in order to determine, for example, an ideal point of application for the minimum required force and the best possible draping result.

[0032] In particular, a combination of the determination of a displacement vector (trajectory) and a rotation of a local coordinate system of network nodes of a draping model between 2D and 3D based on the draping simulation, where vectors and rotations together result in a transformation matrix and required data is obtained from the draping model, and the calculation of required draping forces and their direction, which are introduced into a material via effective surfaces in order to realize a reliable and wrinkle-free draping, can be crucial for basic functionality.

[0033] By determining suitable points of application for minimal force and the best possible draping result, a draping result can be controlled in a targeted manner, whereby subtleties such as material parameters or friction coefficients (between material and shape, between material and material) can be taken into account.

[0034] By calculating the transformation matrices and utilizing flexible manipulation kinematics, a wide variety of geometries can be accommodated. This, of course, is within the reach and load-bearing capacity of the individual manipulation arms. However, this is modularly scalable depending on requirements and can thus be viewed as a generic solution for a wide variety of draping problems.

[0035] "May" refers in particular to optional features of the invention. Accordingly, there is always an embodiment of the invention that has the respective feature or features.

[0036] Using the method according to the invention, various draping tasks can be solved. Draping of different material geometries is enabled. Draping on different deposition geometries is enabled. The number of different effectors required is reduced. Targeted and actively controlled draping is enabled. Draping without relative movement between the material and the effector is enabled. The draping result is improved. The draping effort, in particular time and / or cost, is reduced. Process reliability is increased.

[0037] Exemplary embodiments of the invention are described in more detail below with reference to the figures. Further features and advantages will become apparent from this description. Specific features of these exemplary embodiments may represent general features of the invention. Features of these exemplary embodiments combined with other features may also represent individual features of the invention.

[0038] They show schematically and by way of example: Fig. 1 local coordinate systems of reference points in a planar arrangement and in a multiple and / or spatially curved arrangement with displacement vectors, Fig. 2 a draping process, Fig. 3 an effector with several active modules movable relative to each other when picking up a material, Fig. 4 an effector with several active modules movable relative to each other when depositing a material, Fig. 5 an effector with effector arms and Fig. 6 an effector arm.

[0039] Fig. 1 shows local coordinate systems, such as 100, of reference points, such as 102, in a planar 2D arrangement 104 of a fiber material 106 and in a multiple and / or spatially curved 3D arrangement 108 of the fiber material 106 with displacement vectors, such as 110.

[0040] To produce a fiber composite component, the fiber material 106 is picked up from a receiving surface in the flat 2D arrangement 104 and draped on a surface of a molding tool in the multiple and / or spatially curved 3D arrangement 108.

[0041] For this purpose, a draping model with finite elements and nodes is used. Reference points 102 located at nodes are defined on the fiber material 106 in the planar 2D arrangement 104 and in the multiply and / or spatially curved 3D arrangement 108. The reference points 102 each have a local coordinate system 100. Between the reference points 102, trajectories and rotations of the local coordinate systems 100 are determined. A transformation matrix is ​​determined from the trajectories and rotations of the local coordinate systems 100.

[0042] The transformation matrix thus describes the draping of the fiber material 106 from the flat 2D arrangement 104 to the multiple and / or spatially curved 3D arrangement 108.

[0043] Fig. 2 shows a draping process in a diagram 200. Starting from geometric and material-related boundary conditions 202, a draping simulation 204 is carried out. In a step 206, a draping sequence and a temporal order are determined, and in a step 208, breakpoints are determined. Subsequently, in a step 210, an algorithm for calculating transformation matrices is run through, and an effector is controlled, taking the transformation matrices into account, 212. Furthermore, particular reference is made to Fig. 1 and the corresponding description.

[0044] Fig. 3 shows an effector 300 with several active modules, such as 302, which are movable relative to one another, when picking up a material 304. Fig. 4 shows the effector 300 depositing the material 304.

[0045] The effector 300 has an effector base 306 and movable effector arms, such as 308. The effector base 306 serves to connect the effector 300 to a manipulator of an industrial robot. The effector arms 308 are arranged on the effector base 306. The effector modules 302 are each arranged at the free ends of the effector arms 308. The effector arms 308 each have a plurality of movably connected members.

[0046] The effector modules 302 serve to pick up, hold, and deposit the material without slipping. Using the effector arms 308, the effector modules 302 are movable relative to the effector base 306 and / or relative to each other and independently of each other with a degree of freedom f=6.

[0047] The effector 300 is controlled taking into account transformation matrices. Furthermore, particular attention is paid to Fig. 1 and Fig. 2 and the corresponding description.

[0048] Fig. Figure 5 shows an effector 400 with an effector arm 402 and effector fingers, such as 404. The effector arm 402 has a plurality of arm members movably connected to one another. The effector fingers 404 are arranged at one end of the effector arm 402. The effector fingers 404 each have a plurality of finger members movably connected to one another. The effector arm 402 and the effector fingers 404 are movable by means of actuators. An effector module, such as 406, is arranged at each end of the effector fingers 404. Furthermore, reference is made in particular to Fig. 1 to Fig. 4 and the corresponding description.

[0049] Fig. 6 shows an effector arm 500. The effector arm 500 has a plurality of movably connected arm members, such as 502, and actuator elements, such as 504, arranged between the arm members 502. The actuator elements 504 can be designed, for example, as pneumatic "muscles." The actuator elements 504 can be controlled by means of an electrical control device. Furthermore, particular reference is made to Fig. 1 to Fig. 5 and the associated description. Reference symbol 100 coordinate system 102 Reference point 104 Recording geometry, 2D arrangement 106 Material, fiber material 108 Storage geometry, 3D arrangement 110 Displacement vector 200 diagram 202 boundary conditions 204 Draping simulation 206 steps 208 steps 210 steps 212 Control 300 Effector 302 Active module 304 Material 306 Effector basis 308 Effector arm 400 Effector 402 Effector arm 404 Effector fingers 406 Active module 500 Effector arm 502 Arm joint 504 Actuator element

Claims

[1] Method for draping a flat material (106, 304) on a support surface using a draping model and an effector (300, 400, 500) with a plurality of active modules (302, 406) which can be moved relative to one another, activated and deactivated, each with a degree of freedom f=6, characterized by that reference points (102) of the material (106, 304) are defined, for the reference points (102) a transformation matrix between a receiving geometry (104) and a depositing geometry (108) is determined and the effector (300, 400, 500) with its active modules (302, 406) is controlled taking into account the transformation matrix. [2] Method according to claim 1, characterized by that, in order to determine the transformation matrix, trajectories of the reference points (102) between the receiving geometry (104) and the depositing geometry (108) are determined. [3] Method according to at least one of the preceding claims, characterized bythat to determine the transformation matrix, rotations of local coordinate systems of the reference points (102) between the receiving geometry (104) and the depositing geometry (108) are determined. [4] Method according to at least one of the preceding claims, characterized by that the draping model has nodes and the reference points lie on nodes. [5] Method according to at least one of the preceding claims, characterized by that material parameters and / or friction values ​​are taken into account. [6] Method according to at least one of the preceding claims, characterized by that a draping order is determined. [7] Method according to at least one of the preceding claims, characterized by that draping is first simulated at least once. [8] Method according to at least one of the preceding claims, characterized by that required draping forces are determined by size and direction. [9] Method according to at least one of the preceding claims, characterized by that holding points are determined for introducing draping forces into the material. [10] Method according to claim 9, characterized by that the material is held at least almost slip-free at the holding points during draping. [11] Method according to at least one of claims 9 to 10, characterized by that one of the breakpoints is designated as the starting point for checking the active modules.

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