Satisfying Ranged Sets of Design Requirements Using Design Capability Indices as Metrics

In this paper we propose the use of design capability indices for use in robust design. These indices allow the design requirements to vary within a certain range. Design capability indices are based on process capability indices from statistical process control and provide an alternate approach to the use of Taguchi’s signal-to-noise ratio which is often used for robust design. Successful implementation of design capability indices ensures that a range of design solutions, representing a family of designs, conforms to a given ranged set of design requirements. The essence of using a design capability index is to predict the spread of the design performance so that the capability of a family of designs to satisfy a range of design requirements can be assessed. The design of a solar powered irrigation system is presented to demonstrate the usefulness of design capability indices. 1 Assistant Professor, Design Methodology Group, Department of Mechanical Engineering, Clemson University, Clemson, SC 29634-0921. 2 NSF Graduate Research Fellow, Systems Realization Laboratory, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405. 3 Senior Research Scientist, Systems Realization Laboratory, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405. 4 Professor, Systems Realization Laboratory, George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332-0405. Corresponding Author.