IDDOV is one of the models of DFSS to achieve Six Sigma performance which starts with the customer and ends with the customer.
Design for Excellence (aka Design for X, DFX) is a systematic approach for designing where X is the objective for the product or process
Taguchi Robust Design is a function of product design. Robust products have a strong signal-to-noise ratio.
Design for Six Sigma (DFSS) helps organizations create new products, services and processes in a way that ensures customer satisfaction.