Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K37/00—Auxiliary devices or processes, not specially adapted for a procedure covered by only one of the other main groups of this subclass
  • B23K37/04—Auxiliary devices or processes, not specially adapted for a procedure covered by only one of the other main groups of this subclass for holding or positioning work
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
  • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
  • B23K31/00—Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by any single one of main groups B23K1/00 - B23K28/00
  • B23K31/02—Processes relevant to this subclass, specially adapted for particular articles or purposes, but not covered by any single one of main groups B23K1/00 - B23K28/00 relating to soldering or welding
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Program-controlled manipulators
  • B25J9/0084—Program-controlled manipulators comprising a plurality of manipulators
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
  • B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
  • B25J9/00—Program-controlled manipulators
  • B25J9/16—Program controls
  • B25J9/1679—Program controls characterised by the tasks executed
  • B25J9/1682—Dual arm manipulator; Coordination of several manipulators
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/37—Measurements
  • G05B2219/37573—In-cycle, insitu, during machining workpiece is measured continuously
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/39—Robotics, robotics to robotics hand
  • G05B2219/39131—Each of the manipulators holds one of the pieces to be welded together
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B2219/00—Program-control systems
  • G05B2219/30—Nc systems
  • G05B2219/45—Nc applications
  • G05B2219/45104—Lasrobot, welding robot

Definitions

• the present invention relates to a method for the welding together of workpieces that are to be joined to each other. Such methods arise to a great extent in the motor industry, for example, and in other industries that mass produce items.
• a number of welding stations are usually arranged in a normal welding line in the motor manufacturing industry.
• the parts that are to be joined by welding in a workstation are fed forwards or transported forwards to these welding stations.
• the parts may consist of either a single stamped sheet metal item or they may consist of such composite parts as have been formed in a preceding welding station.
• the parts that have been fed forwards to the welding station are normally handled at the welding station by manipulating robots that transport the parts to welding fittings and place them in these fittings, where the parts are joined to each other and subsequently welded, normally with the aid of what are known as welding robots.
• a second disadvantage with the method that has been used up until now is that positioning errors during the handling of the parts leads to the preservation of tension in the part when it is fixed into the welding fitting. This takes place even if automatic guidance of the parts into the fitting is arranged, as a result of, among other effects, the tolerances that are present not only in the item but also in the actual welding fitting. This then leads to the structure when welded together being associated with intrinsic tensions, and this may lead to deformation of the welded structure. It is, therefore, necessary, in order to maintain control over this process, to measure the welded structures, at least after certain welding operations. This, naturally, costs money, both in the form of equipment and time for the programming and reprogramming of the equipment.
• the present invention therefore proposes, in order to avoid the problems described above, a new method in which the work- pieces that are to be welded together are held together by robots that place the workpieces relative to each other for joining by welding, in which the robots maintain the work- pieces in these positions while the welding is carried out, and in which a measurement system measures the positions of the workpieces in order to make it possible to adjust the positions of the workpieces before welding takes place.
• Fig. 1 shows a block diagram of the functions in a welding station that is operating according to the method of the present invention.
• the measurement systems 3, 4 monitor continuously the movements of the robots 1, 2, and thus also the positions of the workpieces A, B. When it is determined that the positions of the two workpieces A, B are correct 6, 7, the settings of the robots 1, 2 are locked such that no further movements of them or of the workpieces A, B take place.
• the control arrangement 8 of the welding robot 9 is then activated such that the robot can weld together the workpieces A, B while they are held together and in the correct positions by the robots 1, 2.
• the control arrangement 8 receives measurement data from the measurement systems 3, 4 when the correct welding positions 6, 7 have been achieved for the workpieces A, B, and it can then calculate the welding pathway for the welding robot 9.
• the robots 1, 2 deliver the now welded workpieces A, B to the subsequent workstation 10, which may be a further welding station or it may be an assem- bly station.
• the robots 1, 2 that hold the workpieces A, B during the welding operation move the workpieces A, B in order to facilitate the operation of the weld- ing robot 9, whereby the measurement systems 3, 4 continuously forward information to the control arrangement 8 through the sensors 6, 7 of welding position concerning the current positions of the workpieces A, B, such that the welding robot 9 can carry out the welding at the position at which the workpieces A, B are currently positioned.
• the welding takes place in a fixed welding station, and that the robots 1, 2 hold and displace the workpieces A, B as has been described above in such a manner relative to the fixed welding station that all points that are to be welded, or the line that is to be welded, is carried forward by the robots 1, 2 to the fixed welding station.
• each robot 1, 2 is connected to a dedicated measurement system 3, 4. It may, however, also be arranged that a common measurement system is arranged for the two robots. What is important is that the measurement system can determine the position and orientation of the two workpieces A, B that are to be joined together by welding.
• the positions and orientations of the two workpieces A, B can always be determined through the measurement systems 3, 4 that are connected to the robots 1, 2, and, if any deviations arise from the intended values, feedback takes place through the control unit 5 such that the robots 1, 2 can in this case adjust the values such that the workpieces A, B that are to be welded together are placed at the correct relative posi- tions, and furthermore such that the positions are correct to allow the welding robot 9 to carry out the welding operation.
• the parts that are to be welded together may, in a more complex system, be dynamically optimised in a CAD system, if they have been previously fully measured, and an adjustment of the positions and of the welding line or welding points may be carried out initially in the CAD system, and new nominal positions and orientations can be calculated, which are then to be transmitted to the welding station, in order to control not only the manipulating robots but also the welding robot .
• the possibility is also available, in order to obtain even better control of the welding process, to measure dynamically the position of the welding tool of the welding robot 9. This can be carried out in both of the two cases.
• the welding robot 9 can also be provided, if this is required, with an attachment arrangement in order to attach or to hold the workpieces during the welding process.
• One such technology im- plements a laser triangulation method, in which measurement of certain points on the workpieces that have been determined in advance is carried out.
• the workpieces may for this reason be provided with reflecting tape attached at the intended measurement positions.
• the position of each piece of tape can be determined by the use of a light source and two- dimensional detectors, and the position and orientation of the workpiece can be determined by the use of at least three such points.

Landscapes

• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Robotics (AREA)
• Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Manipulator (AREA)
• Resistance Welding (AREA)

Applications Claiming Priority (2)

Publications (1)

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Family Applications (1)

Country Status (5)

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Citations (2)

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• 2006
  • 2006-07-04 KR KR1020087000711A patent/KR20080034882A/ko not_active Ceased
  • 2006-07-04 WO PCT/SE2006/050240 patent/WO2007004983A1/en not_active Ceased
  • 2006-07-04 CN CN2011103755226A patent/CN102513743A/zh active Pending
  • 2006-07-04 JP JP2008519238A patent/JP2008544860A/ja active Pending
  • 2006-07-04 CN CNA2006800244599A patent/CN101213046A/zh active Pending
  • 2006-07-04 EP EP06758098A patent/EP1899104A1/de not_active Withdrawn

Patent Citations (2)

Non-Patent Citations (1)

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