Modelling and analysis of system robustness

Modelling and analysis of system robustness is of interest to researchers and practitioners for several reasons. Robust systems can minimize product development time, warranty costs, and improve product quality. The problem of attaining system robustness is often not addressed formally because design teams work independently of each other when designing system components. In this paper, a framework is presented for robust system development based upon system modelling, integration analysis, and quality engineering techniques. System robustness is achieved by specifying sub-system configurations within the overall system to minimize subsystem-to-subsystem interactions and overall system sensitivity to noise factors. System modelling represents system structure, captures system requirements and identifies required functional interfaces among system components. Once the interfaces among system components are identified, a component-component interaction matrix of interfaces is developed. Integration analysis then groups system components into subsystems and identifies interfaces (main elements of robustness study) between subsystems. Experimental design techniques are used to identify the combinations of levels of these interfaces, if any, that result in a robust system specification. This identified combination of levels then is incorporated into designing product subsystems and components. The application of the approach is illustrated with an automotive example of the design of a vehicle seat system. Discussion on the importance of system modelling and traditional robust design procedures and on the difficulties associated with the development of robust systems is also presented.