Subproject A2

The focus of the subproject A2 is the development of a complete set of robust design methodology, containing methods, catalogues and design principles, to support product designers to control uncertainty already in early phases of the product development process.

To achieve this, results are covering the model level as well as the methodology level:

The outcome of the first founding period of the SFB 805 was a methodology to develop robust products and processes using a model based integrated product and process development. The focus was the modelling of production processes in early phases of the product development process and control disturbances of the type incertitude.

While the production processes normally can be well determined and characterized by its properties, utilization processes are influenced by users, aging, wearing, market changes etc. and additionally often are transient processes (time depending). Referring to this, the aim of the second period of the project was to expand the existing robust design methodology to control uncertainty in such a way that variable utilization processes and its inherent uncertainties can be analysed, judged and finally controlled by the designer already in early phases of the product development. The chosen approach is based on modularisation to be able to adapt to changes whether from process circumstances or from the technical system itself. To successfully control uncertainty through modularisation the uncertainty within modularisation itself has to be controlled prior. Of major interest in this context is controlling interface uncertainty resulting from additional interfaces between modules.

To describe the interactions between modules, the Contact & Channel Model was enlarged with a concretisation of the working surface geometry. Applying Boolean operations, interactions between modules can now be analysed in terms of design clarity, focussing on force and information transfer.

The design clarity analysis was integrated in the procedure for the development of technical systems according to Pahl/Beitz. The procedure, consisting of opportunistic analysis and synthesis steps, results in a minimum number of function-related properties. Furthermore, the predictability of the system behaviour increases.

To control interface uncertainty, one of the main focusses lay in the identification of uncertainty in technical processes. To allow for that, a purposeful process model was developed, that can be used to investigate uncertainty-process-system relationships in detail.

The overall result is a frontloading centred methodology for the development of robust technical systems, which targets the synthesis of robust solutions considering all life phases of the technical product through extensive process analysis, adaption through modularisation and application of robust design principles. Results of the first and the second phase of SFB 805 can be combined purposefully with the uncertainty mode and effects analysis, leading to an overall framework for identification, judgement and controlling of uncertainty.