Hemming equipment, hemming method and hemming process setting method

Abstract

The invention relates to a method for setting up a roller-type crimping process for crimping a plurality of identical assembly arrangements (50), in which a crimping roller (1) mounted on a robot is guided by the robot according to a predetermined crimping path (4) in order to form crimping edges of the assemblies in the assembly arrangements (50), in which the crimping roller (1) is driven by the robot in order to form the crimping edges of the assemblies in the assembly arrangements (50). According to the invention, a crimping process force (10) exerted on the crimping roller (1) by the robot is detected, the crimping process force (10) can be varied by the corresponding control of the robot, and a target crimping mass (20) to be achieved is preset. The robot is controlled to achieve a target hemming quality (20), taking into account the detected hemming process force (10) and the actual geometry of the hemming edge formed during the forming process. In addition, the invention also relates to a roller-type hemming method provided by the above method, and a roller-type hemming device designed to carry out the above methods.

Description

Technical Field

[0001] The invention relates to a method for setting up a roller hemming process for hemming a plurality of identical component arrangements, wherein a hemming roller arranged on a robot is used to form the hemmed edges of the components in the component arrangement and is guided by the robot according to a predetermined hemming path, wherein the robot can be controlled by a control unit in order to influence the hemming quality of the formed hemmed edge, wherein the hemming process force exerted on the hemming roller during the forming is detected and the hemming process force can be varied by corresponding control of the robot by the control unit. In addition, the invention relates to a roller hemming method and a roller hemming device, which has a hemming robot, at least one hemming roller mounted on a robot hemming head, a control unit and a measuring device. Background Art

[0002] Roller hemming is a proven joining process in the automotive industry for the production of body parts, especially in directly and indirectly visible areas. The main areas of application include the production of additional parts such as tailgates, hoods and doors.

[0003] Especially in production lines, where a high degree of flexibility is required for a wide variety of products, robot-guided roller hemming, i.e. roller hemming, is preferred over conventional machine hemming. The basis for robot-guided roller hemming is a path modeled on the component contour, called the hemming path, which is used to guide the hemming roller to form the hemmed edge. The forces that the robot applies to the component during this process depend on several factors, such as the material, edge geometry, sheet thickness and contour of the component. In addition, there are robot-specific "uncertainties", such as the system rigidity at the respective operating point and the path geometry accuracy of the respective robot type. In practice, these dependencies often require time-consuming optimization during commissioning, in particular indirect corrections of the forces and edge contact points by relative offsets to the neutral geometry path specified in the CAD data (CAD: Computer-Aided Design). In this way, quality optimization is achieved by manually adjusting the offsets of the robot path. Such interventions require a high degree of process expertise and often require several time-consuming and costly optimization cycles to achieve the target hemming quality.

[0004] DE 10 2010 051 025 B4 also discloses a roller hemming device, which has a hemming roller mounted on a robot hemming head of a hemming robot, a control unit and a measuring device. The measuring device includes a position determination part for determining the position of the hemming roller and a force measurement part located between the hemming roller and the joint area of ​​the hemming robot. The control unit is designed to control the position of the hemming roller taking into account the values ​​provided by the measuring device so that the hemming roller can achieve the specified requirements when applying the forming force.

[0005] Furthermore, WO 2013 / 149894 A1 discloses a roller hemming device in which the hemming roller can also be controlled to achieve a predetermined forming force, wherein the required control device is designed to compensate for the variable robot elasticity. This takes into account that the hemming robot and its links and robot axes act as an elastic system with different spring stiffnesses at different axis positions. Thus, a desired forming force setpoint can be specified for a given path and achieved by the roller hemming device without interfering with the path programming of the hemming robot. Summary of the invention

[0006] In this context, the present invention aims to solve the following technical problems: to provide an improved roller hemming process setting method, an improved roller hemming process and an improved robot roller hemming device, in particular to achieve automatic optimization of the hemming quality and further ensure that the obtained hemming quality can be maintained.

[0007] To solve this problem, the invention proposes a method according to claim 1 and a roller hemming method and a roller hemming device according to claims 21 and 22. Further advantageous embodiments of the invention are described in the dependent claims and the description and are illustrated in the drawings.

[0008] The proposed solution provides a method for setting up a roller hemming process, in particular for automatic optimization, suitable for hemming a plurality of identical component arrangements, wherein a hemming roller arranged on a robot is used to form the hemming edge of the components in the component arrangement and is guided by the robot according to a predetermined hemming path. The robot can be controlled by a control unit to influence the quality of the hemming edge formed, wherein the hemming process force actually applied to the hemming roller is detected by the robot and the actual hemming process force can be changed by corresponding control of the control unit. The method also provides for setting a target hemming quality to be achieved, in particular specifying the target hemming quality to be achieved by the control unit, and the robot is controlled by the control unit to achieve the target hemming quality, taking into account the detected actual hemming process force and the actual geometry of the hemming edge formed during the forming process. In particular, the actual geometry after forming is measured. The method advantageously passes through a plurality of iterations until a roller hemming process is established that meets the target hemming quality to be achieved. In this respect, the method steps are repeated in an automated manner in particular. The target hem quality is defined in particular by the geometry of the formed hem edge, wherein in particular the following conditions can be taken into account individually or in any combination: roll-in value; packaging dimensions; outer radius; position of the hem component relative to a defined reference point; edge length; edge width. Furthermore, the target hem quality can also be specified, in particular with regard to the occurrence of cracks in the formed hem edge, the waviness of the formed hem edge and / or surface problems of the formed hem edge. The method is particularly suitable for setting up or optimizing roller hem processes for body components in series production.

[0009] In particular, the invention advantageously provides a control method for at least partially automated setting, in particular at least partially automated optimization of a roller hemming process, which is created by data-based recording and evaluation of relevant influencing variables, in particular actual hemming process forces, further in particular actual hemming process forces and their distribution, and advantageously also including the hemming edge geometry. Preferably, firstly corresponding action recommendations are provided for measures required for setting or optimization, in particular measures influencing the hemming forces, in particular changes in the hemming forces caused by changes in the robot path and / or changes in the contact position of the hemming surface during the robot-guided hemming process. Subsequently, the action recommendations on the part of the system are advantageously mapped autonomously. In particular, self-learning algorithms designed specifically for the application can be used to reduce the number of required setting or optimization cycles.

[0010] Advantageously, during the formation of the hemming edge, the hemming path is also detected. In particular, the specified hemming path is detected by reading data about the specified hemming path. In particular, the hemming path is recorded as a series of discrete values, in particular points. According to a further advantageous embodiment, the actual hemming path, i.e. the actual hemming path of the hemming operation, is recorded. The hemming path is advantageously detected from the actual hemming process forces detected and the actual geometry detected. Alternatively or additionally, the actual hemming path can also be detected by measuring means, in particular by optical sensors, in particular by at least one camera. In particular, in this configuration, each hemming roller is assigned its own camera and calibrated accordingly. Further, such an optical sensor system can also be used for measuring components. Further, it is also advantageous to detect the assembly position of the internal components by detecting the respective mounting hole positions by means of an optical system, in particular by means of the above-mentioned optical sensor system. In particular, points of the actual hemming path, in particular the support points of the actual hemming path, and the roller displacements applied in the process, which are advantageously applied in the process, can be detected as part of the hemming path detection. By detecting the hemming path, it is advantageous to assign the measured actual hemming process forces to the path points, in particular by means of a time-based association. By detecting and recording the applied path displacements, a stiffness model can be created at the corresponding path points. Advantageously, the roller hemming process can be set up more quickly.

[0011] According to a particularly advantageous embodiment, the hemming path of the robot controlled by the control unit is described by a limited number of points representing the hemming path. Advantageously, the hemming path is clearly defined by these points. Advantageously, at least one property can be assigned to each point on the hemming path. Another advantage is that the roller hemming process can be set or optimized with a high degree of precision.

[0012] Advantageously, a target hemming process force is assigned to the hemming path. In particular, a target hemming process force can be assigned to each point of the hemming path. Thus, a target hemming process force is specified for the entire hemming path in order to perform the hemming operation. The target hemming process force can in particular be specified by a control unit. In particular, a target hemming process force, in particular an initial target hemming process force, can be specified by a human-machine interface. In addition, an advantageous embodiment provides for simulating the roller hemming process to be set by means of computer-aided simulation, wherein the target hemming process force assigned to each point of the hemming path obtained from the simulation, in particular as an initial process control parameter, can advantageously be automatically assigned to these points.

[0013] It is also advantageous to assign the actual hemming process force to the hemming path. Preferably, the actual hemming process force recorded at this point is assigned to each point on the hemming path. The actual hemming process force is advantageously measured during the hemming edge formation process. In particular, a measuring element is arranged between the robot edge part and the hemming roller in order to introduce the force flow into the measuring element. According to an advantageous embodiment, the robot comprises a robot hemming head with an attachment element, a connecting element and a head element, on which the hemming roller is mounted. The connecting element is preferably arranged between the attachment element and the head element, wherein at least a part of the connecting element is designed as a measuring body. At least one sensor element is arranged on the measuring body, which advantageously detects the actual hemming process force. Thus, in particular, the actual hemming process force can be recorded online during the hemming edge formation process and advantageously assigned to the current position of the hemming path. By analyzing the deviation between the actual hemming process force and the target hemming process force, the robot can be controlled in such a way that the actual hemming process force approaches the target hemming process force. This can advantageously optimize the roller hemming process.

[0014] In addition, the method advantageously assigns a target geometry to the hemming path for the formed hemming edge, in particular a target geometry for a target hemming quality to be achieved. In particular, a target geometry is assigned to each point of the hemming path for the formed hemming edge, so that the target hemming quality of the formed hemming edge is preferably specified by the assigned target geometry.

[0015] Advantageously, the target hem quality is specified by assigning a target geometry of the formed hem edge to each point of the hem path. In particular, the target geometry comprises the following parameters, alone or in any combination: roll-in value, package size, outer radius, hem component position relative to a defined reference point, hem length, hem width. In this respect, a large number of parameters can be assigned to a point on the hem path.

[0016] It is particularly advantageous to record the actual geometry of the formed hem edge. The detected actual geometry of the formed hem edge is then assigned to the hem path. In particular, the actual geometry of the formed hem edge detected at this point is assigned to each point of the hem path. The detection of the actual hem process forces and the additional detection of the actual geometry of the formed hem edge are particularly advantageous, because this allows a roller hem process with a predetermined target hem quality to be set up more quickly, which helps to make the setting of the roller hem process more economical and efficient. In particular, the actual geometry can be recorded after the forming of the hem edge has been completed according to the specified hem path. For this purpose, the actual geometry can be recorded in particular by a separate measuring run, which is assigned to the specified hem path, in particular by a robot. The geometry, in particular the actual geometry of the formed hem edge, is preferably recorded by an optical system, in particular using an optical method, in particular laser triangulation or a camera-based method. Alternatively or additionally, the actual geometry of the formed hem edge can also be recorded using a tactile system, in particular using a tactile measuring device. In particular, a measuring roller or a measuring roller arrangement can be moved along the formed bead edge for this purpose.

[0017] According to an advantageous variant, the actual geometry of the formed hem edge is detected online, i.e. during the hem process, in particular directly after the hem edge has been formed. In particular in the case of such an online detection, it is advantageous to use a multi-camera arrangement to detect the hem edge directly in front of the hem roller position and behind the hem roller position, wherein the detected image data are analyzed, in particular for determining the actual geometry. The multi-camera arrangement is preferably mounted on a robot, in particular on a robot head.

[0018] Another advantageous embodiment provides for detecting the actual geometry of the curling edge that has not yet been formed, i.e. the actual geometry before the curling edge is formed, in particular the actual geometry of the curling edge that has not yet been fully formed, i.e. the curling edge of the pre-curling. Advantageously, each point of the curling path can be assigned an actual geometry of the curling edge that has not yet been formed recorded at this point. Advantageously, this configuration is therefore particularly suitable for detecting the original state of the curling edge before the curling edge is formed or further formed. For this purpose, in particular, the actual geometry can be recorded by an independent measurement run, which is assigned to a specified curling path, wherein the measurement run is especially performed by a robot. Preferably, one or a combination of the following parameters related to the actual geometry are recorded before the curling edge is formed: opening angle, curling length, achieved pre-curling angle, position of the uncurled component relative to a defined reference point, position of the pre-curled component relative to a defined reference point, block gap size. The actual geometry before forming the curling edge is preferably recorded using the same measurement technology as after the curling edge is formed. Therefore, the geometry, in particular the actual geometry before the curling edge is formed and / or the actual geometry of the formed curling edge, is preferably recorded by an optical system and / or a tactile system. Advantageously, at least one of the following conditions is recorded for the geometry: roll-in value, package size, outer radius, achieved pre-curling angle, opening angle, position of the uncurled component relative to a defined reference point, position of the curled component relative to a defined reference point, block gap size, curling length, curling width.

[0019] It is also advantageous to assign a valid robot stiffness model to a specified hemming path. Preferably, the stiffness model takes into account the individual arrangement of the hemming rollers on the robot, in particular on the robot edge, in particular on the robot edge. Preferably, a stiffness or spring constant applicable to this point is assigned to each point of the hemming path. In particular, the recorded stiffnesses can be used to create a model that is used to improve the response to a target hemming quality specification, such as "reduced roll-in by one-twentieth of a millimeter", so that the corresponding hemming process can be set up faster. In particular, the stiffness model facilitates compensation for different stiffnesses or different spring constants depending on the position of the individual robot links and the extension of the robot. In particular, a robot spring constant applicable to this point can be assigned to each point of a specified hemming path.

[0020] In order to achieve a target hem quality, and thus in particular to bring the actual hem quality as close as possible to the target hem quality, and further in particular to bring the actual geometry as close as possible to the target geometry, the hem roller is advantageously adjusted in the method, wherein the hem roller is preferably changed by a robot. By changing the position of the hem roller relative to the hem edge to be formed, the hem process forces can be advantageously influenced. Furthermore, the hem opening angle can also be influenced accordingly, in particular by changing the position of the hem roller.

[0021] In another advantageous embodiment, the actual variable detected in the first curling operation, in particular the actual curling process force detected and / or the actual geometry of the curling edge formed, is closer to the target variable, in particular the target curling quality, the target geometry and / or the target curling process force, in the subsequent second curling operation. In particular, the curling edge of the first component arrangement can be formed in the first curling operation, and the curling edge of the second component arrangement can be formed in the second curling operation. However, in particular in this case, the curling edge of the first component arrangement is formed as part of the pre-curling process in the first curling operation, and in the second curling operation, this curling edge will be formed as a further (pre) curling step. Therefore, the actual variable can be as close to the target variable as possible through multiple pre-curling operations and / or a large number of final curling operations, that is, in particular in an iterative process. In this embodiment, the actual variable will not be closer to the target variable in the ongoing curling operation. However, if the actual geometry is recorded online, this configuration can be provided to set up the curling process faster. Advantageously, in this embodiment, taking into account the actual variables recorded for the hemming path points that have been hemmed during the first hemming operation, the robot will be controlled at subsequent hemming path points to reduce the difference between the actual variables and the target variables.

[0022] According to another particularly advantageous variant of the method, the hemming process, in particular the roller hemming process to be set, is additionally simulated in a computer-aided simulation model. In particular, the simulation can be carried out at the same time as the actual hemming operation, which means that in particular a large number of these simulations can be carried out at the same time as the actual hemming operation. Advantageously, the actual variables recorded during the execution of the actual method, in particular the actual hemming process forces and / or the actual geometry of the formed hemming edge and / or the actual geometry of the not yet formed hemming edge, are transferred to the simulation model. The variables of the actual variables on which the simulation model is based, in particular based on the calculations carried out, are advantageously replaced by the actual variables transferred. Taking these actual variables and the target hemming quality to be achieved, it is advantageous to then simulate the adjustment of the hemming rollers with the robot, in particular until the target hemming quality is achieved in the simulation model. The next actual hemming operation will advantageously be carried out with this simulated hemming roller positioning. Advantageously, this allows the setting of the hemming process to be carried out more quickly. Another advantage is that the simulation can be carried out before the actual hemming process, in particular in parallel with the actual hemming process. Advantageously, the computer-aided simulation model may use certain simulation values ​​as initial process control parameters for setting up the method for the hemming process. Advantageously, this allows for a faster setting up of the hemming process.

[0023] In particular, the method for setting up a curling process is implemented as a method for optimizing the curling quality, in particular for a subsequent roller curling of a plurality of identical component arrangements, and / or as an intermediate method for ensuring the curling quality, in particular in an already set up roller curling process.

[0024] Furthermore, a roller hemming method is proposed for hemming a plurality of identical component arrangements, in particular for at least partially automated hemming, wherein a hemming roller on a robot is used to form the hemmed edge of the components in the component arrangement, and the robot guides the hemming roller according to a set roller hemming process and a predetermined hemming path, wherein the roller hemming process is set according to the method designed according to the invention. The roller hemming process is set in particular before the start of the hemming production of the plurality of identical component arrangements and / or during the hemming production of the plurality of identical component arrangements, in which case it is advantageous to further ensure a consistent hemming quality.

[0025] In addition, a roller hemming device is proposed, comprising a hemming robot with at least one hemming roller mounted on a robot hemming head, a control unit, and a measuring device, wherein the roller hemming device is designed to perform the method according to the invention. In particular, the roller hemming device comprises a first measuring device for detecting the hemming process force, and a second measuring device for detecting the hemming geometry, in particular the actual geometry of the formed hemming edge and / or the actual geometry of the not yet formed hemming edge. In particular, a hemming robot is also provided, comprising a robot hemming head with an attachment element, a connecting element and a head element on which the hemming roller is mounted. The connecting element is preferably arranged between the attachment element and the head element, wherein at least a part of the connecting element is designed as a measuring body. At least one sensor element is mounted on the measuring body, and the measuring body is preferably designed to detect the actual hemming process force, thus in particular as a first measuring device. The second measuring device preferably may comprise an optical system and / or a tactile system, wherein the respective system is arranged to detect the actual geometry, in particular by laser triangulation or camera-based detection. Advantageously, the roller hemming device can comprise a multi-camera system as the second measuring device, wherein the multi-camera system is preferably mounted on the robot hemming head. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Further advantageous details, features and embodiment details of the invention are explained in more detail in conjunction with the exemplary embodiments shown in the figures, including:

[0027] Figure 1 A simplified schematic diagram showing an exemplary embodiment of a roller hemming device designed in accordance with the present invention;

[0028] Figure 2A perspective view showing a robotic hemming head of an exemplary embodiment of a roller hemming device designed in accordance with the present invention;

[0029] Figure 3a A schematic diagram showing the arrangement of the components with the parameters related to the actual geometry recorded before the hemming operation;

[0030] Figure 3b A schematic diagram showing the arrangement of the components after the pre-hemming operation with the parameters related to the actual geometry recorded;

[0031] Figure 3c A schematic diagram showing the arrangement of the components after the final hemming operation with the parameters related to the actual geometry recorded;

[0032] Figure 4 A schematic diagram showing the arrangement of components with an optical system for detecting the actual geometry of the hemmed edge;

[0033] Figure 5a A schematic diagram showing an exemplary embodiment of a method for setting up a roller hemming process to hem a plurality of identical component arrangements according to the present invention is shown;

[0034] Figure 5b A flow chart is shown for explaining a method according to another exemplary embodiment of the present invention for setting up a roll hemming process to hem a plurality of identical component arrangements.

[0035] In the various figures, identical components are generally denoted by the same reference symbols and are therefore sometimes explained only in one of the figures. DETAILED DESCRIPTION

[0036] Figure 1 A schematic diagram of an exemplary embodiment of a roller hemming device 100 designed according to the invention is shown, the device comprising a hemming robot 2 and a control unit 5. The robot 2 comprises an articulated robot arm, which in the exemplary embodiment comprises a first link 201 and a second link 202. A robot hemming head 40 is arranged at the end of the robot arm. The force flow from the robot edge to the hemming roller 1 passes through a measuring unit in order to detect the actual hemming process forces. Figure 2An advantageous design example of a robotic hemming head 40 is shown. The robotic hemming head 40 comprises an attachment element 41, a connection element 42, a head element 43, which can be designed as an integral component in particular, and several hemming rollers 1, which are arranged on the head element 43 and can be used for different hemming operations. The connection element 42 is arranged between the attachment element 41 and the head element 43. The connection element 42 is designed as a measuring body 44, on which several sensor elements 45 are arranged for detecting the hemming force (actual hemming force) applied by the hemming roller 1 to the hemming edge during the hemming operation. In the present exemplary embodiment, the measuring body 44 together with the sensor elements 45 forms a sensor unit for detecting the hemming force. By means of the individual hemming rollers 1, a component arrangement arranged on a hemming bed can be hemmed. Such a component arrangement in particular comprises a first component and a second component, and is further particularly suitable for a first body component and a second body component of a motor vehicle.

[0037] By folding over the component edge of the first component using one of the hemming rollers 1, the first component and the second component can be connected together according to a predetermined hemming path. In this connection process, the actual hemming process forces can be detected by the measuring body 44 and the sensor element 45 arranged thereon. The hemming path is described by a finite number of points, which represent the hemming path controlled by the robot 2 via the control unit 5. During the connection process, i.e. the hemming process, each point of the hemming path is assigned a detected actual hemming process force. In addition, the robot hemming head 40 also includes a sensor device 6, in particular an optical system, for digital geometry and position detection by laser triangulation. By means of this sensor device 6, the roller hemming device 100 is able to detect the geometry of the unformed and formed hemming edges in the component arrangement. In the present exemplary embodiment, the robot 2 performs an additional measuring run specified by the hemming path for this purpose without hemming. Advantageously, the roller hemming device 100 is designed to carry out the method according to the invention. For more details of an advantageous embodiment of the hemming head 40 of the robot 2 of the roller hemming device 100, refer to Figure 2 Provide explanation.

[0038] like Figure 2In the example shown, the robotic hemming head 40 comprises an attachment element 41, a connecting element 42, a head element 43 and a plurality of hemming rollers 1, wherein the connecting element 42 is located between the attachment element 41 and the head element 43, and the hemming rollers 1 are mounted on the head element 43. The hemming rollers 1 have different designs and are arranged in a star shape on the head element 43. By using these hemming rollers 1 of different designs, in particular for hemming operations with different component arrangements and / or different component geometries, a variety of hemming operations can be performed using the robot 2. A portion of the connecting element 42 of the robotic hemming head 40 is designed as a measuring body 44, on which a plurality of sensor elements 45, in particular a plurality of strain gauges with different directions, are mounted. The measuring body 44 and the sensor elements 45 form a sensor unit for detecting the hemming process force applied by a hemming roller 1 to the hemming edge during the hemming operation. As shown Figure 2 As shown, the measuring body 44 can be designed as a column. In addition, the measuring body 44 is designed to be elastically deformable, and the sensor element 45 attached to the measuring body 44 is designed to detect the elastic deformation of the measuring body 44. The measuring body 44 can be formed by the recess and the support structure ( Figure 2 The frame structure (not explicitly shown) is advantageously constructed as a frame structure, in particular with a defined elastic deformation behavior, so that the deformation that occurs can advantageously be clearly assigned to specific hemming process forces.

[0039] In the present exemplary embodiment, the attachment element 41 of the robot crimping head 40 is designed as a docking plate, by which the robot crimping head 40 can be mounted on a Figure 1 The robot arm of the robot 2 shown in FIG. A computing unit ( Figure 2 The computing unit is used to detect and process the sensor signal provided by the sensor element 45 and transmit the processed data to the Figure 1 The control unit 5 of the roller hemming device 100 shown is provided for further use. However, in particular, the sensor signal can also be transmitted directly to the control unit 5 of the roller hemming device 100. According to different embodiments, the calculation unit or control unit 5 advantageously comprises a microprocessor unit and a measuring amplifier (the microprocessor unit and the measuring amplifier are not explicitly shown in the figure) for processing the (strain) signals recorded on the measuring body 44. Advantageously, the target hemming process force curve for the predetermined hemming path is also stored in the control unit 5 and is saved for this purpose in a corresponding storage unit of the microprocessor unit. In the control unit 5, the individual hemming paths are represented by a plurality of points, wherein each point is assigned a target hemming process force for the point.

[0040] The calculation unit or control unit 5 is also designed to detect the actual hemming process force curve from the sensor signals detected by the sensor element 45 on the measuring body 44 during the hemming operation. It is envisaged that when the hemming operation is performed according to the predetermined hemming path, when one of the hemming rollers 1 of the robot hemming head 40 is guided along the component arrangement according to the predetermined hemming path, the actual hemming process force occurring at each point of the hemming path is determined and the recorded values ​​of the hemming process force are assigned to each point of the hemming path. The assignment of these values ​​is advantageously stored, and then an overall curve of the actual hemming process force is generated from the stored value assignment.

[0041] The control unit 5 is also designed to compare the detected actual hemming process force with the target hemming process force stored in the control unit 5 and to detect deviations between the actual hemming process force and the target hemming process force. Taking these detected deviations into account, the control unit 5 is then used to adjust the subsequent hemming operation so that the deviation between the subsequently detected actual hemming process force curve and the target hemming process force curve is reduced. Advantageously, the control unit 5 also takes into account the actual geometry of the reshaped hemming edge detected by the sensor device 6 when adjusting the hemming process force and adjusts the hemming process force applied by the hemming roller 1 by changing the position of the hemming roller 1 by the robot 2. Further advantageously, if there are multiple pre-hemming operations, the control unit 5 also takes into account the actual geometry of the unshaped hemming edge at least during the initial hemming operation. In particular, the control unit 5 is designed to control a corresponding drive of the hemming robot 2, which can be used to influence the way in which the hemming roller 1 acts on the hemming edge to be formed.

[0042] The actual geometrical parameters of the unformed curling edge 302, the partially formed curling edge 301 in the pre-curling operation and the fully formed curling edge 301 can advantageously be recorded individually or in combination as the actual geometrical shape. Figure 3a , Figure 3b and Figure 3c Shown in. Figure 3a to Figure 3c A component arrangement 50 consisting of a first component 51 and a second component 52 is shown, wherein the component arrangement 50 is arranged on a crimping bed 53 . Figure 3a to Figure 3c The point 60 indicated in the drawing, as the upper edge of the crimping bed 53, represents a reference point relative to which some parameters are recorded. The side surface 66 of the crimping bed 53 serves as a further reference surface for recording the parameters. In particular, these parameters can be recorded by appropriately equipped measuring devices, in particular by optical measuring methods, and / or by reading corresponding specifications if the parameters, such as the edge length 38, are known in advance and have low tolerances.

[0043] and Figure 3aParameters relevant to the arrangement of the components in the hemming operation, i.e. before the hemming operation and therefore with an unformed hemming edge, are: the hemming length 38, the so-called block gap dimension, i.e. the distance between the unformed hemming edge 302 and the end edge of the portion of the second component 52 to be covered by the fully formed hemming edge; the opening angle 34, i.e. the angle of the unformed hemming edge 302 relative to the first component 51 resting against the second component 52; and the outer radius 32, described by the unformed hemming edge 302 and the first component 51 resting against the second component 52. In addition, the position 35 of the unhemmed component 51 relative to a defined reference point 60 is also recorded.

[0044] If the component arrangement is pre-crimped in the pre-crimping step with a pre-crimping force of 15, the following further parameters are recorded after pre-crimping: Figure 3b As shown in the example, in particular the achieved pre-curling angle 33, i.e. the angle of the now partially formed curling edge 301 relative to the first component 51 which is in contact with the second component 52, and the rolling-in value 30, i.e. the shortest distance between the outermost point of the partially formed curling edge 301 and a straight line passing through the reference point 60 and parallel to the not yet formed curling edge 302.

[0045] If the component arrangement is completely crimped after the crimping step of applying the crimping force 16, as Figure 3c As shown in the example, the roll-in value 30 is recorded again. In addition, the edge width 39, i.e. the width of the fully formed edge 301, is also recorded. In addition, the packaging dimension 31, i.e. the total thickness of the components 51 and 52 in the area of ​​the formed curled edge 301, is also recorded. The outer radius of the formed curled edge 301 can be recorded as a further parameter, preferably in different quadrants. Advantageously, the outer radius 32 of the formed hem flange 301 is detected in the first quadrant and the outer radius 29 of the formed hem flange 301 is detected in the second quadrant. In addition, the position 36 of the curled component 51 relative to the defined reference point 60 can also be detected.

[0046] Figure 4 An optical system 6 is shown, by means of which the actual geometry can be detected, for example by means of laser triangulation ( Figure 4 61 and 62).

[0047] Combination Figure 5a and Figure 5b An exemplary embodiment of a roller hemming method for roller hemming a plurality of identical component arrangements 50 designed according to the present invention is explained below. Figure 5a As schematically shown in FIG. 1 , during the roller hemming process, a Figure 5aThe hemming roller 1 on the hemming machine (not shown) is guided by the robot along a predetermined hemming path 4 according to a set roller hemming process to form a hemmed edge of a component of the component arrangement 50. In particular, the method and the robot are controlled by a control unit 5. In order to ensure that the hemming result of the roller hemming process meets the predetermined hemming quality, it is necessary to accurately set the roller hemming process. To this end, in the exemplary embodiment, a method for setting a roller hemming process to hem a plurality of identical component arrangements 50 is provided, and combined with Figure 5b The flow chart shown is explained in more detail. The setting of the roller hemming process is controlled by a control unit 5 which can be designed in particular as an ECU (ECU: Electronic Control Unit).

[0048] In order to set up the roller hemming process, firstly in step S1 a component arrangement 50 with a first component 51 and a second component 52 is provided, which will also be the component arrangement 50 that will be processed in large quantities later by the roller hemming process. For this component arrangement 50, the actual geometry 13 of the not yet formed hemmed edge 302 is recorded in the measurement process S2. In the present exemplary embodiment, the measuring run S2 is carried out by the robot according to the hemming path 4 provided for the specific component arrangement 50, wherein the optical system installed on the hemming head of the robot detects the opening angle 34, the edge length 38, the block gap size 37, the outer radius 32 and the position 35 of the unhemmed component relative to the defined reference point as parameters of the actual geometry 13 of the not yet formed hemmed edge 302 and transmits them to the control unit 5. The hemming path 4 is described by a finite number of points in the control unit 5 that represent the hemming path, and each point of the hemming path 4 is assigned the recorded individual parameters 32, 34, 35, 37.

[0049] In the following step S3, the hemming roller 1 mounted on the robot for forming the hemmed edge of the component of the component arrangement 50 is guided by the robot on a predetermined hemming path 4, for which purpose the robot is controlled by a control signal C1 generated by a control unit 5. The control signal C1 can be described as a series of control signals for a complete hemming operation over the entire hemming path 4, in particular based on the hemming path 4 assigned to the control unit 5, and the target hemming quality 20 assigned to the control unit 5, which is defined in this exemplary embodiment by the following parameters: edge width 39, package size 31, position 36 of the hemming component relative to a specified reference point, roll-in value 30, outer radius 32 of the first quadrant and outer radius 29 of the second quadrant. Over the entire hemming path 4, the parameters of the target geometry of the formed hemmed edge are each assigned to each relevant point of the hemming path 4. The control signal C1 specifies the target hemming process force 21 that should be applied by the hemming roller 1 to the hemming edge during the forming process. A target hemming process force 21 can be initially assigned to the control unit for each point of the hemming path 4, while in a subsequent process the target hemming process force 21 for each point of the hemming path 4 can be determined by the control unit 5 itself. However, it can also be provided in particular that the target hemming process force 21 is initially determined by the control unit 5 taking into account the stiffness model 7 stored in the control unit 5, wherein the stiffness model 7 takes into account in particular the robot geometry and robot properties, up to the change in stiffness of the hemming roller, in particular the robot, on the hemming path and the resulting change in the spring constant of the robot.

[0050] During the hemming edge shaping in step S3, the actual hemming process force 10 applied by the robot to the hemming roller 1 during hemming along the hemming path 4 is also detected and transmitted to the control unit 5. The actual hemming process force 10 detected at this time is assigned to each point of the hemming path 4. In addition, the actual hemming path 11 of the hemming roller 1 is also recorded during the shaping process and transmitted to the control unit 5. The points of the hemming path and the parameters recorded at each point can advantageously be recorded as a value tuple. In this regard, the control unit 5 uses in particular the displacement of the hemming path as an input variable.

[0051] After the hemming operation along the entire hemming path 4 is completed, the final hemming operation (optionally, a pre-hemming operation) is provided in the exemplary embodiment, followed by a measuring operation S4, in which the actual geometry 12 of the formed hemming edge is recorded by an optical system mounted on the robot hemming head. To this end, the following parameters are recorded and transmitted to the control unit 5: roll-in value 30, packaging size 31, outer radius 32 of the first quadrant, outer radius 29 of the second quadrant. These parameters are also assigned to each relevant point on the hemming path 4. In one embodiment of the method, the hemming operation can also be a pre-hemming operation, in particular the pre-hemming angle 30 in the actual geometry 12 of the formed hemming edge is also recorded as a parameter.

[0052] After the measuring run S4, the control unit 5 evaluates in step T whether the detected actual geometry 12 corresponds to the specified target geometry 22. If the actual geometry 12 deviates from the target geometry 22 within a defined tolerance range, the actual geometry 12 corresponds to the target geometry 22. If the detected actual geometry 12 does not correspond to the target geometry 22 ( Figure 5b ” (marked “N” in the figure), the new but identical arrangement of components is hemmed in step S3 by correspondingly adjusted control of the robot, the adjustment of the hemming roller 1 by the robot being changed by the adjusted control signal C1. The control signal C1 is adjusted to achieve a target hemming quality 20, in this case a target geometry 22, taking into account the actual hemming process forces 10, the actual hemming path 11 and the actual geometry 12 of the formed hemming edge. In the subsequent further hemming operation, the actual variables recorded in the hemming operation, in particular the parameters of the actual geometry 12 of the formed hemming edge, will therefore come closer to the target variables, in particular the parameters of the target geometry 22 of the formed hemming edge.

[0053] After step S3, a measuring run S4 is performed again and the hem result is evaluated in step T. These steps are repeated as long as the evaluation in step T shows that the detected actual geometry 12 does not correspond to the target geometry 22 (N). On the other hand, if the evaluation T shows that the detected actual geometry 12 corresponds to the target geometry 22 of the formed hem edge ( Figure 5bIf, in FIG. 1 , the actual geometry 12 of the formed curling edge is determined (marked as "Y"), the curling process is set up, in particular for a subsequent curling operation in step M. In this curling operation M, the same component arrangement is performed using the control signal Cadj set in the previous method step. After a specified number of identical component arrangements have been curled, for example 200, a measuring run S5 can be carried out for quality assurance, and then in step T it is evaluated whether the detected actual geometry 12 of the formed curling edge still corresponds to the target geometry 22 of the formed curling edge. If so (Y), the curling process remains unchanged and step M is continued. If the actual geometry 12 of the formed curling edge no longer corresponds to the target geometry 22 of the formed curling edge (N), steps S3, S4 and T are re-executed. The curling process is thus set up again.

[0054] according to Figure 5b In a variant of the method described in , the hemming process can be simulated in a computer-aided simulation model 8. The simulation model 8 takes into account the material characteristic parameters of the component arrangement, the component dimensions and the component geometry before hemming and works with forces as input variables, while the control unit 5 controlling the robot 2 advantageously works with displacements relative to the hemming path as input variables. The stiffness model 7 advantageously "mediates" between the two. The actual variables recorded in the measuring runs S2, S4, S5 and transmitted to the control unit 5 are forwarded from the control unit 4 to the simulation model 8. These actual variables are used by the simulation model 8 to simulate the hemming process, wherein the adjustment of the hemming roller 1 to be performed by the robot is simulated taking into account these actual variables and the target geometry 22 to be achieved until the target geometry is achieved in the simulation model 8. Furthermore, the next actual hemming operation will be carried out in step S3 with the position of the hemming roller 1 simulated in the simulation model, i.e. the control signal C1 is adjusted accordingly. If it is found after the measuring run S4 and the evaluation step T that the target hem quality is not achieved, the simulation model 8 advantageously takes into account the actual variables recorded in the measuring run and the actual hem process forces recorded during the hem operation in step S3 and makes corresponding adjustments. Furthermore, by means of the computer-aided simulation, the number of actual hem operation steps S3 and measuring runs S4 can be reduced, which makes the setting of the hem process more economical and faster.

[0055] The exemplary embodiments shown in the drawings and explained in conjunction with the description serve to illustrate the invention and not to limit it.

[0056] Reference numerals list

[0057] 1. Hemming roller

[0058] 2. Robot

[0059] 201 robot connecting rod

[0060] 202 robot connecting rod

[0061] 3. Hemmed Edges

[0062] 301 formed hemmed edge

[0063] 302 Unformed curled edge

[0064] 4 hemming paths

[0065] 5Control Unit

[0066] 6Optical system

[0067] 7 Stiffness Model

[0068] 8 Simulation Model

[0069] 10 Actual hemming process force

[0070] 11Actual hemming path

[0071] 12 Actual geometry of the formed hem edge (301)

[0072] 13 Actual geometry of the unformed hem edge (302)

[0073] 15 Pre-curling force

[0074] 16 Final crimping force

[0075] 20 Target hemming quality

[0076] 21 Target hemming process force

[0077] 22 Target Geometry

[0078] 29 The outer radius of the second quadrant

[0079] 30 Roll-in value

[0080] 31 Packing Size

[0081] 32Outer radius of the first quadrant

[0082] 33Achieved pre-curling angle

[0083] 34 opening angle

[0084] 35 Position of the uncurled component relative to the defined reference point

[0085] 36 Position of the hemmed component relative to the defined reference point

[0086] 37 Block Gap Size

[0087] 38 Edge length

[0088] 39 Edge Width

[0089] 40 Robot hemming head

[0090] 41 Attachment elements

[0091] 42 Connecting elements

[0092] 43Head element

[0093] 44 measuring body

[0094] 45 Sensors

[0095] 50 components arrangement

[0096] 51 First Component

[0097] 52 Second Component

[0098] 53 roll-up bed

[0099] 60 reference points

[0100] 61 Laser beam

[0101] 62 laser beams

[0102] 66 Reference surface

[0103] 100 hemming equipment

[0104] S1 provides a component arrangement planned for series production

[0105] S2 measurement run to record the actual geometry of the unformed hem edge

[0106] S3 performs hemming operations according to specifications

[0107] S4 measurement run to record the actual geometry of the formed hem edge

[0108] S5 measuring run to record the actual geometry of the hem edge formed during the set hem process

[0109] shape

[0110] T Evaluate whether the actual recorded hem quality corresponds to the specified target hem quality

[0111] M performs hemming operation using the completed hemming process

[0112] C1 control signal

[0113] Control signal set by Cadj

Claims

1. A method for setting up a roller hemming process, suitable for hemming a plurality of identical component arrangements (50), wherein a hemming roller (1) mounted on a robot (2) is guided by the robot (2) along a predetermined hemming path (4) to form a hemming edge (3) of a component in the component arrangement (50), wherein the robot (2) can be controlled by a control unit (5) to influence the hemming quality of the formed hemming edge (301), wherein during the forming process, an actual hemming process force (10) acting on the hemming roller (1) by the robot (2) is detected and the hemming process force (10) can be changed by corresponding control of the robot (2) by the control unit (5), wherein a target hemming quality (20) to be achieved is preset, characterized in that Taking into account the detected actual hemming process forces (10) and the actual geometry (12) of the formed hem edge (301) resulting from the forming, the robot (2) is controlled by the control unit (5) to achieve the target hem quality (20).

2. The method according to claim 1, characterized in that The curling path (4) is also detected during the forming process.

3. The method according to claim 1 or 2, characterized in that The hemming path (4) for the control of the robot is described by a finite number of points representing the hemming path (4), the control of the robot being carried out by the control unit (5).

4. The method according to claim 3, characterized in that A target hemming process force (21) is assigned to each point on the hemming path (4).

5. The method according to claim 3 or 4, characterized in that Each point on the hemming path (4) is assigned the actual hemming process force (10) detected at that point.

6. The method according to any one of claims 3 to 5, characterized in that A target geometry (22) of a formed hem edge (301) is assigned to each point on the hem path (4).

7. The method according to any one of claims 3 to 6, characterized in that Each point is assigned the actual geometry (12) of the formed hem edge (301) detected at that point.

8. The method according to any one of the preceding claims, characterized in that Before the beaded edge (3) is formed, the actual geometry (13) of the not yet formed beaded edge (302) is detected.

9. The method according to any one of the preceding claims, characterized in that The geometric shape (301, 302) is detected by an optical system (6) and / or a tactile system.

10. The method according to any one of the preceding claims, characterized in that The actual crimping path (11) is determined by the detected actual crimping process forces (10) and the detected actual geometry (13).

11. The method according to any one of the preceding claims, characterized in that The actual crimping path (11) is determined by measurement.

12. The method according to any one of the preceding claims, characterized in that The robot (2) has a robot crimping head (40), which includes an attachment element (41), a connecting element (42) and a head element (43) on which a crimping roller (1) is mounted, wherein the connecting element (42) is arranged between the attachment element (41) and the head element (43), and at least a part of the connecting element (42) is designed as a measuring body (44), and the measuring body (44) detects an actual crimping process force (10) by means of at least one sensor element arranged on the measuring body (44).

13. The method according to any one of the preceding claims, characterized in that An effective stiffness model of the robot (2) is assigned to the predetermined hemming path (4).

14. The method according to any one of the preceding claims, characterized in that At least one of the following conditions is recorded for the geometry (12, 13) of the curled edge (3): roll-in value (30); packaging size (31); outer radius (32); achieved pre-curling angle (33); opening angle (34); position of the uncurled component relative to a fixed reference point (35); position of the curled component relative to a fixed reference point (36); block gap size (37); curling length (38); curling width (39).

15. The method according to any one of the preceding claims, characterized in that The adjustment of the crimping rollers is varied by the robot (2) to achieve the target crimping quality (20).

16. The method according to any one of the preceding claims, characterized in that The actual variables (10, 11, 12) recorded in the first hemming operation are closer to the target variables (20, 21, 22) in the subsequent second hemming operation.

17. The method according to any one of the preceding claims, characterized in that Taking into account the actual variables (10, 11, 12) detected for the hemmed points on the hemming path in the first hemming operation, the robot (2) is controlled to reduce the difference between the actual variables (10, 11, 12) and the target variables (20, 21, 22) for subsequent points of the hemming path (4).

18. The method according to any one of the preceding claims, characterized in that The hemming process is further simulated in a computer-aided simulation model (8), wherein the detected actual variables (10, 11, 12) are transmitted to the simulation model (8) and the actual variables on which the simulation model (8) is based are replaced by the transmitted actual variables (10, 11, 12), and the adjustment of the hemming roller (1) is simulated taking into account these actual variables (10, 11, 12) and the target hemming quality (20) to be achieved until the target hemming quality (20) is achieved in the simulation model (8), and then this simulated adjustment of the hemming roller (1) is used for the next hemming operation.

19. The method according to claim 18, characterized in that The computer-aided simulation model (8) specifies certain simulation values ​​as initial process control parameters (4, 21) for setting up a method for a roller hemming process.

20. The method according to any one of the preceding claims, characterized in that The method is implemented as a method for optimizing the quality of the crimping and / or as an intermediate method for ensuring the quality of the crimping.

21. Roller hemming method for hemming a plurality of identical component arrangements (50), wherein a hemming roller (1) mounted on a robot (2) is guided according to a defined roller hemming process and a predetermined hemming path (4) to form hemmed edges (3) of the components in the component arrangement (50), characterized in that: The roller hemming process is provided according to the method as claimed in any one of the preceding claims.

22. A roller hemming device (100), comprising: A hemming robot (2) having at least one hemming roller (1) mounted on a robot hemming head (40), a control unit (5), and a measuring device (6, 44), characterized in that the roller hemming device (100) is designed to perform the method described in any one of the preceding claims.

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