Design for excess capability to handle uncertain product requirements in a developing world setting

Abstract

Products designed for the developing world often go unused or underused by the intended customers. One cause of this problem is uncertainty regarding the actual requirements of customers in the developing world. This can result when designers, with experience in technologically advanced countries, apply their own value structure to the products they design. Because of the designers’ lack of experience in the culture and environment of the developing world, the actual requirements are only partially known to them. This problem can be mitigated by (i) optimizing product flexibility and adaptability to react to uncertain requirements, and (ii) reducing the most critical uncertainties. The flexibility of a product to adapt to new or changing requirements has been shown to extend the service life of large complex engineered systems (e.g., aircraft carriers, aircraft, communication systems, and space craft). These systems must remain in service for extended periods of time, even though the environments and requirements may change dramatically. Applying these proven techniques to products designed for the developing world can alleviate the problem of uncertain requirements. This paper presents and demonstrates a technique aimed at improving the success of developing world engineering projects. Flexibility and adaptability minimize the impact of uncertainties, and are enabled by numerically optimized amounts of designed-in excess. A sensitivity analysis performed on the system model helps the designer prioritize the set of uncertain requirements and parameters for refinement. The technique is demonstrated in the design of a cookstove intended for use in the developing world.