DE102011115834A1 - Method for adjusting holding unit for holding workpiece used in motor vehicle, involves adjusting position of support surface based on the comparison of actual position and desired position of support surface - Google Patents

Abstract

The method involves positioning holding unit (2) in working position, and measuring actual position of a support surface of the holding unit. The actual position and desired position of the support surface are compared. The position of the support surface is adjusted based on the comparison result. An independent claim is included for device for adjusting holding unit for holding workpiece.

Description

State of the art

The present invention is based on a method for adjusting at least one holding device for holding at least one workpiece to be machined, in particular in a welding and / or assembly line for motor vehicle bodies. Furthermore, the present invention is based on a system for machining workpieces, in particular in a welding and / or assembly line for motor vehicle bodies.

It is known that parts of motor vehicle bodies are processed in welding and assembly lines, in particular welded and joined. The workpieces are in this case clamped in a plurality of holding devices in the form of clamping devices and then joined by welding by means of an industrial robot. The clamping points of the clamping devices and in particular the arrangement of the clamping devices are adapted specifically to the geometry and contour of the workpieces to be machined. Usually, the clamping devices have two clamping jaws, between which the workpiece is clamped in order to fix the workpiece or the workpieces for joining or welding in a well-defined position. To achieve the highest possible quality and precisely crafted end product, in particular a motor vehicle body, a very accurate positioning and alignment of the clamping devices in the initial construction of the welding and / or assembly line is necessary. The clamping devices are usually assembled from high-precision manufactured consoles and contour pieces, which are mounted on a base formed as a base body. However, because of the manufacturing tolerances of the individual elements, clamping devices and clamping points can never exactly correspond to the specification, in particular the predefined CAD data. When assembling the individual parts, the manufacturing tolerances rather add up. In addition, geometry deviations also arise due to the assembly of the individual parts. In order to achieve the exact nominal position for each individual clamping point, the clamping surfaces of the clamping devices are measured manually and adjusted by means of exchangeable tuning plates. The position correction thus takes place via the change in thickness of discrete tuning plates, which are each arranged between the contour pieces and the console

Disclosure of the invention

It is an object of the present invention to provide a method for adjusting at least one holding device, which allows a more precise and flexible alignment of the holding surfaces of the holding devices compared to the prior art and also faster and less expensive to perform. Another object of the present invention is to provide a system for machining workpieces whose fixtures are more precise, flexible, faster and easier to adjust.

This object is achieved with a method for adjusting at least one holding device for holding at least one workpiece to be machined, in particular in a welding and / or assembly line for motor vehicle bodies, wherein in a first method step, the holding device is prepositioned in a working position, wherein in a second method step Is measured actual position of a holding surface of the holding device, wherein in a third method step, the measured actual position is compared with a desired position and wherein in a fourth method step for position adjustment, the holding surface with a machining tool as a function of a detected in the third step deviation between the Actual position and the target position is processed.

The method according to the invention has the advantage over the prior art that in the working position of the holding device, the correctly positioned holding surface is automatically produced by machining with the processing tool. Compared to the prior art, therefore, no adjustment to be made by hand is necessary. The adjustment of the holding device is achieved in the inventive method by machining the holding surface. To set the desired position and / or orientation of the holding surface (collectively referred to as the desired position) material from the holding surface as long as either removed or applied until the actual position corresponds to the desired position. For this purpose, material is preferably removed from the holding surface, preferably by milling, grinding, sawing and / or laser ablation, in the fourth method step by means of the processing tool. The machining tool thus preferably comprises a milling tool, a grinding tool, a saw and / or a laser. Alternatively, it is also conceivable that material is applied to the holding surface, preferably by means of laser deposition, welding, soldering, gluing and / or printing. In particular, by means of the milling process, a completely constructed arrangement of holding devices is brought to predetermined desired positions in a simple and time-saving manner, thereby compensating for tolerances resulting from manufacturing and structural uncertainties. Alternatively, it is conceivable that the inventive method for adjusting part of a manufacturing process for producing the holding device or a system of several Holding devices, wherein by means of the adjustment method, the desired desired geometry is created in the region of the holding surfaces. In an advantageous manner, the holding device is not adjusted in particular by an exchange of discrete tuning plates, but the holding surface itself is brought directly into the correct position. The adjustment is thus much more flexible and precise. In particular, with the method according to the invention, even the smallest deviations can be corrected automatically in comparison with the prior art. Furthermore, also deviations in the orientation of the holding surface are to be compensated. Another advantage of the method according to the invention is that the adjustment of the at least one holding device is fully automatic and thus comparatively time-saving and inexpensive to carry out. A fully automatic detection of the positions of the holding surfaces during the adjustment process also allows a permanent comparison with the corresponding three-dimensional CAD data for the workpiece to be machined. Furthermore, accurate electronic logging of the adjustment, for example for quality assurance purposes, is easy to implement. For carrying out the method according to the invention, in particular those holding devices are used which have comparatively much material and in particular over the desired positioning too much material in the region of the holding surface, so that by a targeted and especially iterative Wegfräsen material in the region of the holding surface, the actual position can be reached. In particular, a multiplicity of holding devices are adjusted with the method according to the invention. It is conceivable that in this case each of the holding devices is individually measured and milled or that several holding devices are first measured one after the other and then several holding devices are milled successively. Another advantage of the method according to the invention is that much greater manufacturing tolerances in the manufacture of the holding device, ie in particular in the manufacture of the console, contour pieces, jaws, base body and the like, can be allowed, since the deviations from the desired position in time after assembly the holding device and be corrected in time in the later working position after the pre-positioning of the holding device. In this way, a significant reduction in manufacturing costs can be achieved. Furthermore, the use of lightweight constructions (for example, sandwiched components) for producing the main body and / or the brackets or holding devices is made possible by the inventive method in particular. Such lightweight constructions usually have higher tolerances than precise solid material parts to be produced, and these larger tolerances can be compensated by the method according to the invention in a simple, precise and fast manner. The use of such lightweight constructions advantageously again allows considerable material and weight savings.

Advantageous embodiments and modifications of the invention are described in the dependent claims, as well as the description with reference to the drawings.

Another object of the present invention is a method for adjusting at least one holding device for holding at least one workpiece to be machined, in particular in a welding and / or assembly line for motor vehicle bodies, wherein in a first method step, the holding device is prepositioned in a working position, wherein in a second method step, an actual position of a holding surface of the holding device is measured by means of an optical position measuring system, wherein in a third method step, the measured actual position is compared with a desired position and wherein in a fourth method step for position adjustment, the holding surface as a function of a third method step determined deviation between the actual position and the target position is adjusted. Advantageously, the actual position of the holding surface is measured using an optical position measuring system, so that compared to the prior art, the actual position can be determined with much greater accuracy. Furthermore, this improves the accuracy of the adjustment, so that the quality of machining of the workpieces is to be improved. The adjustment is preferably carried out by means of the milling process. Alternatively, it would also be conceivable to make the adjustment by the targeted exchange of voting plates, by a corresponding control of mechanical adjusting screws or the like.

According to a preferred embodiment, it is provided that the second, third and fourth method steps are repeated until it is determined in a third method step that the deviation between the actual position and the desired position falls below a preset threshold value. Advantageously, the desired position is achieved by iterative measuring and milling of the holding surfaces. It is thus ensured that not too much material is accidentally milled away from the holding surface and thus the desired position is no longer achievable. It is conceivable that an alarm signal is generated when it is determined in the third step that a desired position can not be achieved by milling. In this case, for example, a corresponding contour piece of the holding device can be exchanged.

According to a preferred embodiment, it is provided that in the second method step the actual position is measured by means of a movable about several axes moving device, preferably a robot by a measuring means, in particular a probe, is positioned on the support surface by means of the moving device. In an advantageous manner, in particular the robot is used, which is used in normal operation of the welding and / or assembly line for machining the workpieces. In this way, no separate measuring machine, in particular stand measuring machine is necessary, which is usually used in the prior art for measuring the holding devices. The cost of adjusting the fixture are thereby significantly reduced. For this purpose, a probe is preferably used in the robot head of the robot, conceivable being, for example, switching and measuring probes, as well as switching laser probes and scanning probes.

According to a preferred embodiment, it is provided that in a first sub-step of the second method step, the movement device and in particular the robot is moved so far until the measuring means is positioned on the holding surface, and wherein in a second sub-step of the second method step, the position of the moving device and in particular the Robot is determined from the control signals of the moving device and in particular of the robot and wherein in a third sub-step of the second method step, the actual position of the holding surface from the position of the moving device and in particular of the robot is calculated. Advantageously, a measurement of the holding surface is thus made possible without additional measuring means. The robot head is moved so far until the measuring device contacts the holding surface. The measuring means then announces a contact with the holding surface, whereupon the movement of the robot is stopped. Based on the position of the robot can now be calculated back to the position of the robot head and based on the knowledge of the measuring means used to the position of the holding surface.

According to a preferred embodiment, it is provided that, in a first sub-step of the second method step, the robot is moved until the measuring device held by a robot head is positioned on the holding surface and wherein in a second sub-step of the second method step the position of the robot head is measured by means of a position measuring system and wherein in a third sub-step of the second method step, the actual position is calculated from the measured position of the robot head. In particular, the position measuring system comprises an optical position measuring system, preferably an interferometric laser distance measuring system and particularly preferably a laser tracker. Advantageously, thus a high-precision measurement of the position and orientation of the robot head and thus an accurate determination of the actual position of the support surface is possible. It is conceivable that the position data of the holding surface measured by means of the position measuring method are compared with the position data of the holding surface determined by means of the position of the robot and / or averaged. Advantageously, the position control thus takes place via a combination of a robot-internal and a robot-external measuring method. Compared to the prior art, therefore, an increase in precision is possible. With the help of the laser tracker, the 3D point coordinate of the robot head in a corresponding reference coordinate system, such as the vehicle coordinate system, is detected by a combination of angle measurement and interferometric laser distance measurement. In particular, the laser tracker is a device which transmits a focused laser beam at a certain angle to a reflector means arranged on the robot head and then compares the reflected laser beam with the emitted laser beam. Based on the comparison, the distance to the reflector can be determined, so that a position of the reflector in space can be determined as a function of the distance and the angle. In the second sub-step, in particular, the position of a reflector means arranged on the robot head is thus determined by means of the optical position-measuring system. Preferably, a use of a plurality of laser trackers is provided, which emit measuring beams from different spatial directions on the robot head mounted reflector means, so that the position of the robot head in almost all positions in space are detected accurately.

According to a preferred embodiment, it is provided that before the second method step, the measuring means is received by the robot and wherein prior to the third method step, a milling means is received by the robot. Advantageously, the same robot is thus to be used both as a milling tool and as part of the optical measuring system for measuring the holding surfaces. Additional measuring or machining tools are therefore not needed for adjustment.

According to a preferred embodiment it is provided that the holding device comprises a movable between an open state and a closed state tensioning device and wherein in the first process step, the tensioning device is transferred to an open state and wherein the tensioning device at least during the second and / or fourth Process step is kept in the open state. The clamping device comprises in particular two clamping jaws, between which the at least one workpiece can be introduced during the opened state and between which the at least one workpiece is clamped in the closed state and thus fixed. The surfaces of the clamping jaws facing the workpiece comprise in particular the holding surfaces in the sense of the present invention. Alternatively, holding surfaces may for example also be simple contact surfaces of a holding device on which the at least one workpiece rests. For milling the holding surfaces, the holding device is preferably in the open state, so that the robot head has sufficient freedom of movement. In the open state, in particular both a milling of the holding surface of the fixed clamping jaw, as well as a milling of the holding surface of the movable clamping jaw moving during the change between the open and the closed state is conceivable.

According to a preferred embodiment, it is provided that the opening state and in particular the opening angle and / or an axis of rotation of the clamping device in the second method step is measured by means of the position measuring system and wherein in the fourth method step depending on the measured opening state and the measured actual position of the holding surface, the theoretical actual Position of the holding surface for the closed state of the clamping device is calculated and wherein in the fourth method step further, the theoretical actual position is compared with the desired position. Advantageously, an adjustment of a clamping device is possible in this way, even if the holding surface to be adjusted is arranged on a movable clamping jaw of the clamping device. In this way an adjustment of both clamping jaws of the clamping device is thus possible. The movable clamping jaw has for this purpose preferably a reflector means, so that by means of the optical position measuring system of the opening state, in particular the opening angle and the position of the axis of rotation can be measured. This has the advantage that the holding surface is measured and milled in the open state of the clamping device, while the actual actual position of the holding surface is calculated in the closed state from the knowledge of the opening angle, the position of the axis of rotation and the position of the holding surface in the open state. In particular, a calculation of the gap width and gap position between the clamping jaws in the closed state is possible in this way.

Another object of the present invention is a method for producing a system for machining workpieces, in particular for a welding and / or assembly line for motor vehicle bodies, wherein the system comprises at least one holding device for holding at least one workpiece to be machined, wherein in a first manufacturing step the at least one holding device is mounted on a plate-like base body, which is designed in particular as a solid body or as a multi-part lightweight body, and wherein in a second manufacturing step, the holding device is adjusted according to a method according to one of the preceding claims. The production of the system is substantially simplified and accelerated by the use of the method according to the invention for adjusting the at least one holding device of the system in comparison to the prior art. The production of the system is thus cheaper to implement. Preferably, in the first manufacturing step for producing the holding device, a head piece is fastened to a tubular stand, in particular, and a clamping device movable between an open and a closed state is fastened to the head piece. In the first manufacturing step, the stand is then further attached to the plate-like base body.

Another object of the present invention is a system for machining workpieces, in particular in a welding and / or assembly line for motor vehicle bodies, comprising at least one holding device for holding a workpiece to be machined and a robot for processing the workpiece, wherein the robot and / or the holding device has at least one reflector means for cooperating with an optical position measuring system. Advantageously, a reflector means disposed on the robot head allows the adjustment of the holding devices by the method according to the invention, since the position of the robot head with the optical position measuring system can be precisely determined and thus the robot head for measuring the position of the holding surfaces using the measuring means and / or for editing, For example, milling, the holding surfaces using the processing means, such as the milling means, is usable. Furthermore, a reflector means arranged on the holding device makes it possible to determine the opening state and the opening angle and / or a rotation axis of the holding device, so that the method according to the invention can also be used in particular with a holding device that can be moved between an open position and a closed position. The reflector means is preferably arranged on the movable part of the holding device.

Another object of the present invention is a system for machining workpieces, in particular for a welding and / or assembly line for motor vehicle bodies, comprising at least one holding device for holding at least one workpiece to be machined, wherein the holding device has at least one milled for adjustment holding surface. Advantageously, therefore, a system is provided whose retaining surfaces have been adjusted by means of a milling operation. In this way, comparatively low manufacturing tolerances can be realized with reduced production costs and production times compared to the prior art.

Another object of the present invention is a system for machining workpieces, in particular in a welding and / or assembly line for motor vehicle bodies, comprising at least one holding device for holding a workpiece to be machined and a robot for processing the workpiece, wherein the system further comprises an optical Position measuring system which is configured to determine an actual position of a holding surface of the holding device. Advantageously, the optical position measuring system allows an adjustment of the at least one holding device and in particular the plurality of holding devices with the inventive method, so that a comparatively time-saving and thus cost-effective design of the system is made possible. Furthermore, this allows the use of components with higher manufacturing tolerances to build the system, so that the overall cost of the system can be further reduced. As already described above, the optical position measuring system particularly preferably comprises a laser tracker.

According to a preferred embodiment, it is provided that the optical position measuring system for measuring a position and / or orientation of a robot head of the robot is configured using the reflector means, and wherein the optical position measuring system has an evaluation unit which is used to calculate the actual position of the holding surface as a function of measured position of the robot head is configured. The robot head preferably carries a measuring means, in particular in the form of a probe. There is a fixed geometric relationship between the measuring device and the robot head, so that the position of the measuring device contacting the holding surface can be determined by means of the evaluation unit from the position of the robot head. In this way, a fully automatic measurement of the holding surfaces using the robot is possible. Alternatively, it is conceivable that the robot is designed in the form of the movement device.

According to a preferred embodiment it is provided that the evaluation unit is configured to compare the actual position with a desired position and wherein the system further comprises a control unit for controlling a guided by the robot processing means, preferably the milling means, in dependence of a detected by the evaluation unit deviation between the actual position and the desired position. Advantageously, the robot is controlled by means of the control unit for milling the holding surface in such a way that the actual position approaches the desired position successively. In this way, a fully automatic adjustment of the holding surfaces by means of the robot is possible. The milling means preferably comprises a milling spindle guided by the robot head. The milling means advantageously allows a milling made of metal retaining surfaces.

Another object of the present invention is the use of a robot, which is provided for machining held by means of workpieces in a welding and / or assembly line for motor vehicle bodies, for adjusting at least one of the holding devices. Advantageously, therefore, a robot, which is arranged anyway in the region of the holding devices for processing the workpieces, used for the adjustment and in particular for measuring and / or correcting (by milling) the holding surfaces.

According to a preferred embodiment it is provided that a plurality of holding devices is mounted on a particular plate-like body, which is designed as a multi-part lightweight body. From the prior art it is known to screw the holding devices on the base body in the form of solid steel plates. The holding devices are also formed as solid steel and / or castings, so that the tolerances during assembly are minimized. In the method and system according to the invention, the manufacturing tolerances and the tolerances resulting from the assembly of the individual components are considerably easier and more precise to compensate. Advantageously, thus the use of the lightweight body is made possible, which can be saved in comparison to the prior art material and weight. The weight reduction also has the advantage that the body is easier to handle and can also be performed or held by smaller robots. Preferably, the holding device comprises a head piece, a particular tubular stand and a movable between an open and a closed state clamping device, in particular the clamping device is preferably releasably secured via the head piece at a first end of the stand and a first end opposite the first end in the longitudinal direction second end the stator is preferably releasably attached to the plate-like base body.

According to a preferred embodiment, it is provided that the base body comprises two mutually spaced base plates, between which a preferably cross- and / or honeycomb-like support structure is arranged, wherein the support structure is preferably formed of a plurality of cross-nested and particularly preferably welded together web elements and wherein most preferably the support structure is welded to both base plates. Advantageously, thus a comparatively inexpensive, lighter and still stiffer body is achieved. The base plates preferably have a uniform grid of passage and attachment openings, so that the holding devices can be arranged at different locations of the base plates, depending on the application. The web elements are preferably provided with a plurality of recesses in order to save weight and material. Furthermore, the space between the two base plates is suitable for carrying, in particular, electrical, pneumatic and / or hydraulic supply lines for the holding devices (for example for actuating the opening and closing mechanism of the toggle lever clamping devices). The sides of the body are preferably closed with suitable diaphragms.

According to a preferred embodiment, it is provided that one end of at least one of the holding devices is guided through a through opening of a base plate and is positively and / or non-positively inserted into fastening openings of the other base plate, wherein the holding device preferably further screwed with at least one of the two base plates and / or welded. Advantageously, thus a simple and stable attachment of an example designed as a hollow profile end of the holding devices is achieved on the body. In the region of the passage opening, the hollow profile is preferably clamped by means of an adapter element screwed to the base plate, while the outermost end of the hollow profile has a toothed contour such that the teeth engage in corresponding slot-shaped fastening openings in the other base plate. This has the advantage that the holding devices are to be fastened from one side of the main body to the base body.

Further details, features and advantages of the invention will become apparent from the drawings, as well as from the following description of preferred embodiments with reference to the drawings. The drawings illustrate only exemplary embodiments of the invention, which do not limit the essential inventive idea.

Brief description of the drawings

1 FIG. 12 is a schematic perspective view of a system and fixtures adjusted for a method, according to an exemplary embodiment of the present invention, respectively. FIG.

2 FIG. 12 is a schematic plan view of a system and fixtures adjusted according to a method, according to another exemplary embodiment of the present invention. FIG.

3 shows a schematic perspective view of a holding device of a system according to the exemplary embodiments of the present invention.

4 schematically shows a method for adjusting holding devices according to another exemplary embodiment of the present invention.

5a . 5b . 5c . 5d show schematic perspective views of a base body and details of a main body of a system according to another exemplary embodiment of the present invention.

6a . 6b . 6c show schematic views of a main body and a holding device of a system according to another exemplary embodiment of the present invention.

7a . 7c show schematic views of a main body and a holding device of a system according to another exemplary embodiment of the present invention.

8th shows a schematic perspective view of a head piece of a holding device of a system according to another exemplary embodiment of the present invention.

Embodiments of the invention

In the various figures, the same parts are always provided with the same reference numerals and are therefore usually named or mentioned only once in each case.

In 1 is a schematic perspective view of a system 1 and holding devices 2 adjusted according to a method each illustrated according to an exemplary embodiment of the present invention. The system 1 is in the present example part of a welding and assembly line for the construction of motor vehicle bodies. The system 1 includes a plurality of holding devices 2 for holding or fixing workpieces 3 (in 1 not shown) are provided. The holding devices 2 are on a common body 11 attached. Some of the fixtures 2 are in particular designed as clamping devices, which each comprise two clamping jaws, namely a movable and an immovable clamping jaw. The movable jaw is pivotable about an axis of rotation relative to the fixed jaw, so that the clamping device between an open state (clamping jaws are spaced apart) for inserting and removing the workpieces 3 and a closed state (jaws are spaced apart only by a thin gap) for fixing one or more workpieces 3 , Other fixtures 2 may preferably only one support surface for one or more workpieces 3 exhibit. The respective contact surfaces of the holding devices 2 , which for fixing the workpieces 3 with the workpieces 3 to come into direct contact, below are for all types of holding devices 2 always as holding surfaces 2 ' designated. The system 1 also has a robot 4 on, for editing the workpieces 3 is provided. For example, the robot 4 a welding tongs performed, which for welding the means of the holding devices 2 fixed workpieces 3 serves. The positioning and alignment of the fixtures 2 is specific to certain geometries and contours of the workpieces to be machined 3 set. The quality of the vehicle bodies to be produced largely depends on the accuracy with which the holding devices 2 were set. As the main body 11 and the individual holding devices 2 in their manufacture are subject to certain manufacturing tolerances, which add together in the assembled state, and also arise deviation due to the assembly, the system 1 in the assembled and in the final position (also referred to as working position) prepositioned state can be adjusted before the actual machining process for producing the vehicle body parts can begin.

The adjustment is in the present example with the help of the robot head 4 ' of the robot 4 performed, the robot head 4 ' this successively a measuring means 7 in the form of a probe and a milling medium 8th picks up. First, the robot attacks 4 the measuring device 7 and is controlled by a control unit such that the probe from the robot 4 in the area of a holding surface 2 ' a holding device to be adjusted 2 is brought. When the probe the holding surface 2 ' touched, a stop signal is generated and the robot 4 is stopped. Now the exact position of the robot head 4 ' in space, in particular in the vehicle coordinate system, by means of an optical position measuring system 6 . 6 ' measured. The optical position measuring system 6 ' includes at least one laser tracker, which with one on the robot head 4 ' arranged reflector means 5 interacts. For the purposes of the present invention, the term laser tracker is understood to mean, for example, a device which comprises at least one with a focused laser beam 18 (also referred to as measuring beam) working distance meter. For example, with the help of a two-axis rotatable mirror, the direction of the laser beam 18 on the target point on the robot head 4 set and detected with the rotary encoders associated with the rotary axes. The target point to be measured is provided with a reflector means designed as a retroreflector 5 (In particular cube-corner prism or arrangement of three mutually perpendicular mirrors) provided, wherein the retroreflector the laser beam incident thereon 18 the laser tracker reflected back to this. In this case, the reflected laser beam passes 18 coaxial with the emitted laser beam 18 when the laser beam 18 exactly centered on the reflector means 5 coincides, and offset in parallel when the laser beam 18 not centered on the reflector means 5 meets. Depending on the embodiment of the laser tracker, it is concluded from a comparison of the emitted and reflected laser light to an absolute distance between the laser tracker and target point and / or a change in this distance. The position of the reflector or of the target point relative to the laser tracker is calculated from the angles detected by the angle encoders and the distance detected by the distance meter. In this way, the exact position of the robot head 4 ' be determined in space and in particular in the vehicle coordinate system. In this way, the laser tracker thus allows by means of the laser beam 18 and the robot head 4 ' mounted reflector means 5 the determination of the 3D position of the milling medium 8th' relative to the laser tracker. In addition, the laser tracker also has an additional measuring unit, which determines the orientation of the milling medium 8th' allowed, so that the exact position and orientation of the robot head 4 ' can be determined in space and in particular in the vehicle coordinate system.

Between the robot head 4 ' and the probe has a fixed and known geometric relationship, so that by means of an evaluation unit, the exact position of the probe and thus the exact position of the support surface 2 ' can be calculated. In this way, the exact actual position of the holding surface 2 ' determined. Alternatively or additionally, it is conceivable that the exact position of the robot head 4 ' when the probe is the holding surface 2 ' touched, is determined by means of control signals of a robot-internal control and / or sensors and from this the actual position of the holding surface 2 ' is determined. Preferably, the respective actual position is determined in both ways and the two actual position compared and / or averaged. The accuracy is thus further increase. Furthermore, a plausibility check of the determined data is possible in this way.

The evaluation unit then compares the actual position with the desired nominal position of the corresponding holding surface 2 ' For example, from the given CAD data for the system 1 , and determines, if present, a deviation between the actual position and the desired position for this one holding surface 2 ' , For position correction, the robot 4 then controlled by the control unit such that the measuring means 7 against the milling agent 8th' is exchanged and the holding surface 2 ' with the milling agent 8th is milled as a function of the deviation between actual position and nominal position. The holding devices 2 factory are preferably designed such that the holding surface 2 ' always have significantly more material than for the fully adjusted system 1 necessary is. In this way, although all retaining surfaces must be for adjustment 2 ' all fixtures 2 Milled, but it is prevented solely by milling the retaining surfaces 2 ' An adjustment is not possible because, for example, on a support surface 2 ' not removed material, but instead material would have to be applied. During the milling process, the correct position of the robot head 4 ' and thus the milling means 8th' by means of the robot-internal control and sensor system and / or by means of the optical position measuring system 6 ' supervised. By the controlled Frasverfahren then the removal of material takes place in the area of the holding surface 2 ' , which changes the position of the holding surface 2 ' approaches the target position. Subsequently, the milling agent 8th' again against the measuring device 7 exchanged in order to again measure the new actual position and compare it again with the desired position. If the deviation between the actual position and the desired position still does not fall below a preset threshold value, ie the actual position deviates too much from the desired position, a further milling operation (as described above) is carried out. These steps are repeated until the desired position is reached with the preset accuracy. With each milling process, preferably only so little material is removed that there is no danger that in the next adaptation step material would have to be applied in order to reach the desired position. Should material still be missing, an alarm signal is preferably generated, and a retaining surface exhibiting holding element of the respective holding device, in particular the entire jaw is automatically or manually exchanged for a thicker holding element. In an analogous manner, then another holding surface 2 ' the same holding device 2 or a holding surface 2 ' another holding device 2 adjusted. The procedure is carried out or repeated until the system 1 completely adjusted.

Alternatively, it would also be conceivable that the respective actual positions of several holding surfaces, in particular a plurality of holding devices, are measured one after the other and subsequently the several holding surfaces are milled in succession. This has the advantage that fewer tool changes are necessary and thus the adjustment time is reduced.

In 2 is a schematic plan view of a system 1 and holding devices 2 , adjusted according to a method respectively according to another exemplary embodiment of the present invention, shown. This in 2 illustrated system 1 is essentially the same as in 1 illustrated system 1 , The illustrated system 1 is also with the basis of the 1 explained adjustment procedure set. In 2 are also illustrative workpieces 3 drawn to form a motor vehicle body, which after the implementation of the adjustment process in the normal operating state of the system 1 from the robot 4 edited and meanwhile from the fixtures 2 be fixed. Unlike the in 1 shown system 1 has the optical position measuring system 6 ' in 2 a total of three laser trackers, which from three different directions, the position of the robot head 4 ' measured. Accordingly, the robot head 4 ' three different reflector means 5 on. The use of multiple laser trackers has the advantage that regardless of the position of the robot 4 always at least one reflector means 5 from one of the laser trackers to determine position and orientation.

In 3 is a schematic perspective view of a holding device 2 of a system 1 according to the exemplary embodiments of the present invention. The 3 shows in particular a detail view of in 1 and 2 only schematically illustrated holding devices 2 , The holding device 2 includes a clamping device with a stationary jaw 19 and one opposite the immovable jaw 19 movable jaw 20 , The movable jaw 20 is about a rotation axis 21 pivotable, allowing the tensioning device between the open state 9 and the closed state 10 , in particular pneumatically, is switchable. When closed 10 is between the two jaws 19 . 20 formed a gap in which the at least one workpiece 3 (not shown) is to fix. The gap width is thereby through the two retaining surfaces 2 ' Are defined. For adjusting the holding device 2 the clamping device is in the open state 9 brought that so that measuring Equipment 7 by means of the robot 4 on the holding surfaces 2 ' can be arranged. At least the movable jaw 20 further comprises a reflector means 5 on, so that by means of the laser tracker, the opening state of the jaw 20 can be evaluated. By an evaluation of the movement of the reflector means 5 is by means of the evaluation of the exact opening angle of the clamping device in the open state 9 , as well as the exact location of the axis of rotation 21 to determine. The evaluation unit calculates from the robot head 4 and the measuring means 7 certain actual position of the holding surface 2 ' the movable jaw 19 in the open state 9 the tensioning device taking into account the opening angle and the position of the axis of rotation 21 the actual actual position of the holding surface 2 ' the movable jaw 19 in the closed state 10 the tensioning device. The actual actual position is then compared with the desired position and the holding surface 2 ' If necessary, milled to match the nominal position. The holding surface 2 ' the immovable jaw 19 is, however, in the open state 9 adjust immediately without such conversion being necessary. It is conceivable that the robot head 4 ' for the final check of the adjusted clamping device additionally a measuring gauge engages and in a closed state 10 inserted clamping device in the gap. Alternatively, of course, it would be conceivable that the gap width directly with a particular robot head 4 guided corresponding sensor in the closed state 10 is checked. To produce a finished console for the system described above 1 will the in 3 shown tensioning device preferably on an L-shaped head piece 17 attached. The head piece 17 will be on a stand 22 (in 3 not shown) attached to the body 11 (in 3 not shown) is mounted.

In 4 is a flowchart schematically a method of manufacturing and adjusting a system 1 according to another exemplary embodiment of the present invention. In the first production step 30 become the single components of the system 1 , in particular the basic body 11 , the head piece 17 , the stand 22 and the tensioning devices, manufactured individually. In the subsequent second production step 31 become the individual holding devices 2 in particular each from head piece 17 , Stand 22 and clamping device mounted. In the third production step 32 become the holding devices 2 on the body 11 mounted and brought into their future working position. Subsequently, in a fourth production step 33 for adjusting the system 1 the holding surfaces 2 ' each holding device 2 by means of the robot 4 and the laser tracker brought to their respective desired position according to predetermined CAD data (milling and measuring as described above). In a final fifth production step 34 become the final inspection of the system 1 again all actual positions of the holding surfaces 2 ' by means of the robot 4 guided measuring means 7 and the laser tracker measured and automatically logged for quality control.

In 5a . 5b . 5c . 5d show schematic perspective views of a body 11 and details of a body 11 a system according to another exemplary embodiment of the present invention. The inventive method and system described above 1 allows a much simpler and more precise compensation of manufacturing tolerances of the individual parts and resulting from the assembly of the individual components tolerances. For this reason, here is the use of a multi-part lightweight body as the body 11 allows, which can be saved in comparison to the prior art material and weight. The weight reduction also has the advantage that the body 11 easier to handle and can also be run or held by smaller robots. The in 5a schematically illustrated basic body 11 comprises two mutually parallel base plates 12 . 12` , Between the two base plates 12 . 12 ' is a carrier structure 13 arranged through which the two base plates 12 . 12 are spaced apart perpendicular to their main extension plane. The base plates 12 . 12 ' each comprise a stamped and / or laser-cut sheet metal plate, with a uniform grid of passage and mounting holes 15 . 16 for flexible reception of holding devices 2 anywhere on the base plates 12 . 12 ' (depending on the application) are provided. During the laser cutting of the base plates 12 . 12 ' With reduced laser power, designations and / or coordinates are preferably incorporated in the base plates 12 . 12 ' Branded, showing the assembly of the system 1 using instructions that use the same names and / or coordinates. A single view of a base plate 12 is in 5b shown. The support structure 13 , a single view is in 5c is shown, is made of a plurality of cross-nested web elements 14 built so that a honeycomb-like structure is created. The bridge elements 14 are each with the two base plates 12 . 12 ' additionally (point) welded, so that a comparatively light, yet stiffer basic body 11 arises. In 5b is a detailed view of two cross-nested web elements 14 illustrated. One side of the web elements preferably made of sheet metal 14 is each provided with slots, so that the two web elements 14 against each other in this Schlize can be plugged. The bridge elements 14 are each with recesses 24 provided so that between the base plates 12 . 12 ' Supply lines can be arranged or relocated. In this way, the gap between the two base plates 12 . 13 ' in particular for carrying out electrical, pneumatic and / or hydraulic supply lines for the holding devices 2 (For example, for operating the opening and closing mechanism of the toggle lever jigs) suitable. On the front sides is the main body 11 each with apertures 23 Mistake.

In 6a . 6b . 6c are schematic views of a body 11 and a holding device 2 of a system 1 according to another exemplary embodiment of the present invention. In 6a is an example of a console as part of a holding device 2 shown which on a main body 11 is attached. The console includes a header 17 for holding the clamping device, as well as a stand 22 on which the head piece 17 is attached. The stand 22 in particular comprises a tubular hollow profile made of metal, through which a supply line 25 for the tensioning device is guided in the direction of the clamping device. The lower end of the hollow profile is through a through hole 15 in the upper base plate 12 plugged. The hollow profile is used for fixing in the region of the passage opening 15 from one to the upper base plate 12 screwed clamp 27 clamped. The end portion of the hollow profile is on the lower base plate 12 attached. The end area is either with another clamp 27 clamped, which with the lower base plate 12 is bolted ( 6c ) or the end area is with teeth 26 provided in corresponding slot-like mounting holes 16 in the lower base plate 12 ' engage and there are positively, positively and / or materially secured ( 6b ).

In 7a . 7c are schematic views of a body 11 and a holding device 2 of a system 1 according to another exemplary embodiment of the present invention. In 7a is a plan view of the slot-like mounting holes 16 in the lower base plate 12 illustrated. The mounting holes 16 extend circumferentially about an opening in the base plate 12 ' , In 7b is the end of the stand 22 shown, which with teeth 26 for engagement in the mounting holes 16 is provided.

In 8th is a schematic perspective view of a header 17 a holding device 2 of a system 1 according to another exemplary embodiment of the present invention. The head piece 17 is designed as a hollow lightweight component, by being constructed from appropriately bent and joined sheet metal. The structure of the head piece 17 thus allows a comparatively high material and weight savings compared to manufactured from solid head pieces 17 , The resulting higher manufacturing tolerances can be compensated by the adjustment method according to the invention in a simple and fast manner.

LIST OF REFERENCE NUMBERS

1

system

2

holder

2 '

holding surface

3

workpiece

4

robot

4 '

robot head

5

reflector means

6

Position measuring system

6

Optical position measuring system

7

measuring Equipment

8th

milling tool

8th'

milling means

9

Open state

10

Closed state

11

body

12.12 '

baseplates

13

support structure

14

web elements

15

Through opening

16

fastening opening

17

headpiece

18

laser beam

19

Immovable jaw

20

Movable jaw

21

axis of rotation

22

stand

23

dazzle

24

recess

25

supply line

26

teeth

27

clamp

31-34

manufacturing steps

Claims (24)

Method for adjusting at least one holding device ( 2 ) for holding at least one workpiece to be machined ( 3 ), in particular in a welding and / or assembly line for motor vehicle bodies, wherein in a first method step the holding device ( 2 ) is prepositioned in a working position, wherein in a second method step, an actual position of a holding surface ( 2 ' ) of the holding device ( 2 ) is measured, wherein in a third method step, the measured actual position is compared with a desired position and wherein in a fourth method step for position adjustment, the holding surface ( 2 ' ) with a processing tool ( 8th ) is processed in response to a detected in the third step, deviation between the actual position and the target position. The method of claim 1, wherein in the fourth method step by means of the processing tool ( 8th ) Material from the holding surface ( 2 ' ), preferably by milling, grinding, sawing and / or laser ablation, is removed and / or material on the holding surface ( 2 ' ), preferably by means of laser deposition, welding, soldering, gluing and / or printing. Method, in particular according to one of claims 1 or 2, for adjusting at least one holding device ( 2 ) for holding at least one workpiece to be machined ( 3 ), in particular in a welding and / or assembly line for motor vehicle bodies, wherein in a first method step the holding device ( 2 ) is prepositioned in a working position, wherein in a second method step, an actual position of a holding surface ( 2 ' ) of the holding device ( 2 ) by means of an optical position measuring system ( 6 ' ) is measured, wherein in a third method step, the measured actual position is compared with a desired position and wherein in a fourth method step for position adjustment, the holding surface ( 2 ' ) is adjusted as a function of a deviation determined between the actual position and the desired position in the third method step. Method according to one of the preceding claims, wherein the second, third and fourth method step are repeated until it is determined in a third method step that the deviation between the actual position and the desired position falls below a preset threshold value. Method according to one of the preceding claims, wherein in the second method step, the actual position by means of a movable about several axes moving device, preferably a robot ( 4 ), is measured by means of the movement device, a measuring means ( 7 ), in particular a probe, on the holding surface ( 2 ' ) is positioned. Method according to claim 5, wherein in a first substep of the second method step the robot ( 4 ) until the measuring device ( 7 ) on the holding surface ( 2 ' ), and wherein in a second sub-step of the second method step, the position of the robot ( 4 ) from the control signals of the robot ( 4 ) is determined and wherein in a third sub-step of the second method step, the actual position from the position of the robot ( 4 ) is calculated. Method according to one of claims 5 or 6, wherein in a first substep of the second method step the robot ( 4 ) is moved as far as that of a robot head ( 4 ' ) held measuring means ( 7 ) on the holding surface ( 2 ' ), and wherein in a second sub-step of the second method step, the position and / or orientation of the robot head ( 4 ' ) by means of a position measuring system ( 6 ) and wherein in a third sub-step of the second method step, the actual position from the measured position of the robot head ( 4 ' ) is calculated. Method according to one of claims 5 to 7, wherein in the second partial step, the position and / or orientation of the robot head ( 4 ' ) by means of the optical position measuring system ( 6 ' ), preferably by means of an interferometric laser distance measurement and particularly preferably by means of a laser tracker. Method according to claim 8, wherein in the second partial step the position and / or alignment of a robot head ( 4 ' ) arranged reflector means ( 5 ) by means of the optical position measuring system ( 6 ' ) is determined. Method according to one of the preceding claims, wherein before the second method step, the measuring means ( 7 ) of the robot ( 4 ) and wherein prior to the third method step a processing means for processing the holding surface ( 2 ' ), in particular a milling means ( 8th' ), from the robot ( 4 ) is recorded. Method according to one of the preceding claims, wherein the holding device ( 2 ) one between an open state ( 9 ) and a closed state ( 10 ) comprises movable clamping device and wherein in the first method step, the clamping device in an open state ( 9 ) and wherein the tensioning device at least during the second and / or fourth method step in the open state ( 9 ) is held. The method of claim 11, wherein the opening state and in particular the opening angle and / or a rotational axis of the clamping device in the second method step by means of the position measuring system. 6 ) and wherein in the fourth method step, depending on the measured opening state and the measured actual position of the holding surface ( 2 ' ) the theoretical actual position of the holding surface ( 2 ' ) for the closed state ( 10 ) of the tensioning device is calculated and wherein in the fourth method step further the theoretical actual position is compared with the desired position. Method according to one of the preceding claims, wherein a for processing the workpieces ( 3 ) provided robot ( 4 ) of the welding and / or assembly line for motor vehicle bodies in the second method step for measuring the actual Position of the holding surface ( 4 ) and / or in the third method step as a machining tool for machining the holding surface ( 2 ' ) is used. Method for producing a system ( 1 ) for machining workpieces ( 3 ), in particular for a welding and / or assembly line for motor vehicle bodies, wherein the system ( 1 ) at least one holding device ( 2 ) for holding at least one workpiece to be machined ( 3 ), wherein in a first production step the at least one holding device ( 2 ) on a plate-like base body ( 11 ), which is in particular formed as a solid body or as a multi-part lightweight body, and wherein in a second manufacturing step, the holding device ( 2 ) is adjusted according to a method according to one of the preceding claims. Method according to claim 14, wherein in the first production step for the production of the holding device ( 2 ) a head piece ( 17 ) on a particular tubular stand ( 22 ) and one between an open and a closed state ( 9 . 10 ) movable clamping device on the head piece ( 17 ) and wherein in the first manufacturing step further the stand ( 22 ) on the plate-like base body ( 11 ) is attached. System ( 1 ) for machining workpieces ( 3 ), in particular for a welding and / or assembly line for motor vehicle bodies, comprising at least one holding device ( 2 ) for holding at least one workpiece to be machined ( 3 ) and a robot ( 4 ) for processing the at least one workpiece ( 3 ), whereby the robot ( 4 ) and / or the holding device ( 2 ) at least one reflector means ( 5 ) for cooperating with an optical position measuring system ( 6 ) having. System ( 1 ), in particular according to claim 16, for machining workpieces ( 3 ), in particular for a welding and / or assembly line for motor vehicle bodies, comprising at least one holding device ( 2 ) for holding at least one workpiece to be machined ( 3 ), wherein the holding device ( 2 ) at least one milled for adjustment holding surface ( 2 ' ) having. System ( 1 ), in particular according to one of claims 16 or 17, for machining workpieces ( 3 ), in particular for a welding and / or assembly line for motor vehicle bodies, comprising at least one holding device ( 2 ) for holding at least one workpiece to be machined ( 3 ) and a robot ( 4 ) for processing the at least one workpiece ( 3 ), whereby the system ( 1 ) an optical position measuring system ( 6 ' ), which for determining an actual position of a holding surface ( 2 ' ) of the holding device ( 2 ) is configured. System ( 1 ) according to claim 18, wherein the optical position measuring system ( 6 ) for measuring a position and / or orientation of a robot head ( 4 ' ) of the robot ( 4 ) using the reflector means ( 5 ), and wherein the optical position measuring system ( 6 ' ) has an evaluation unit, which for calculating the actual position of the holding surface ( 2 ' ) depending on the measured position and / or orientation of the robot head ( 4 ' ) is configured. System ( 1 ) according to claim 19, wherein the evaluation unit is configured to compare the actual position with a desired position and wherein the system ( 1 ) a control unit for controlling one of the robot ( 4 ) guided processing means, preferably in dependence of a detected by the evaluation unit deviation between the actual position and the desired position having. System ( 1 ) according to one of claims 16 to 20, wherein a plurality of holding devices ( 2 ) on a particular plate-like base body ( 11 ), which is designed as a solid body or as a multi-part lightweight body. System ( 1 ) according to one of claims 16 to 21, wherein the holding device ( 2 ) a head piece ( 17 ), in particular a tubular stand ( 22 ) and one between an open and a closed state ( 9 . 10 ) has movable clamping device, wherein in particular the tensioning device via the head piece ( 17 ) at a first end of the stand ( 22 ) is preferably releasably secured and a longitudinal end of the second end opposite the first end of the first ( 22 ) on the plate-like base body ( 11 ) is preferably releasably attached. System ( 1 ) according to one of claims 21 or 22, wherein the main body ( 11 ) two mutually spaced base plates ( 12 . 12 ' ), between which a preferably cross- and / or honeycomb-like carrier structure ( 13 ), wherein the support structure ( 13 ) preferably of a plurality of cross-nested and particularly preferably welded together web elements ( 14 ) and most preferably the support structure ( 13 ) with both base plates ( 12 . 12 ' ) is welded. System ( 1 ) according to claim 23, wherein the end of at least one of the holding devices ( 2 ) through a passage opening ( 15 ) of a base plate ( 12 ) and in fastening openings ( 16 ) of the other base plate ( 12 ' ) is inserted positively and / or non-positively, wherein the holding device ( 2 ) preferably with at least one of the two base plates ( 12 . 12 ' ) is also bolted and / or welded.

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