Development of a design methodology for upgradability involving changes of functions

The objective of designs for upgradability is to design products so as to extend the value life. We have proposed a design for upgradability only involving changes of performance. This paper proposes a design for upgradability involving changes of functions such as adding a new function in the next generation. This paper also illustrates a prototype design support tool and its feasibility with a practical design example, a vacuum cleaner.