Changeability assessment in systems during early design

Increased stakeholder expectations and tougher global competition push the manufacturing industries to develop more complex solutions, introducing numerous uncertainties in design decision-making. Incorporating changeability is one way to systematically deal with uncertainty, which requires dealing with the identification, valuation, and quantification of changeability during the early design stages. Besides, when considering system-of-systems (SoS), it necessitates optimising the portfolio of options within the SoS while considering the transition ‘in’ and ‘of’ the system combinatorially. In this light, this paper presents the Changeability Assessment in Systems during Early Design (CASED) method to create value-robust systems in the face of uncertainty. The CASED method utilises epochs and eras to represent uncertainty and analyses the impact of changing system configurations and control policies on overall system value. Considering the transition ‘in’ and ‘of’ the system involves solving a linear assignment problem to minimise the switch costs. A dynamic programming procedure for an era finds the avenues when change shall be exercised. Iterating through several eras, a map of the expected mean value and expected standard deviation is generated for all designs, which guides decisions concerning changeability. The applicability of the method is further confirmed through a fleet of haulers operating in a quarry.