Without any restriction to their general applicability, the present invention as well as the problems on which it is based will be explained with reference to the assembly of multisegment aircraft structures.
Production installations that are used at present for aircraft fuselage manufacture have geometry-defining elements from whose use the final external skin geometry is produced. These geometry-defining elements are normally composed of steel and are manufactured such that the internal streamline shape of the fuselage shells can be fixed to them such that the resultant position of the external streamline shape corresponds to the nominal contour. In this case, it is necessary to ensure that the geometry-defining elements change only within an order of magnitude which is within the acceptable tolerance band throughout the time period of their use, in particular throughout the time period of manufacture of a respective aircraft fuselage.
More modern manufacturing installation technology is already dispensing with these geometry-defining elements and is making use of numerically-controlled (NC) positioning axes for this purpose. In this case, the geometry is achieved by correct positioning of the individual fuselage segments with respect to one another. In this production technique, as in the production technique described above, the process result is checked at the end of the overall process. This is necessary because the production environment does not remain stable throughout the entire process time, for example owing to temperature fluctuations, geological, partial lowering and raising of the production workshops, and the like.
One disadvantage that is being found with the production techniques described above is the fact that, in certain circumstances, it is found as the result of the measurement at the end of the overall process that a discrepancy is present which cannot be tolerated. This circumstance that the discrepancy which cannot be tolerated occurs in a separate process step after completion of all the value-creation stages that have already been carried out, makes these manufacturing concepts financially expensive and unattractive.