# Developing Innovative Crutch Using IDeS (Industrial Design Structure) Methodology
## 3 Case Study
### Design Settings
#### 3.1.1 QFD Method  
At the beginning, the QFD method was applied using the Six Questions process to fill a list of features that define a crutch:  
* Who: those who have suffered injuries or surgeries, amputees with one leg; children (3+), adults and elderly people. From the definition of this target, ergonomics and adjustability became two essential characteristics that the crutch should present. Where: house interior (bathroom, kitchen, living room, bedroom, stairs, slippery floors), outdoors (public transport, road, uneven terrain, parks), other internal spaces (home, pool, gym, office, hospital). From this answer came out that adaptability, hygiene and dimensions are characteristics that should be well designed. * When: every day, whenever it is necessary to use the legs for movements. So, durability and material strength became important characteristics. * How: leaning on it, intermittently or as a support. For this reason, reliability, lightness and affordance are features that should be taken into consideration. * What: stick with grip and underarm support thereof for the forearm with adjustable height. * Why: to help in walking, moving, getting up, sitting, going up and down the stairs, maintain balance, reduce pain, speed up healing and facilitate rehabilitation; maintaining the patient's own autonomy and their own habits without weighing on others. So, the comfort of use becomes very important. Summarizing, the list of features is composed of: 1. Adaptability; 2. Adjustability; 3. Lightness; 4. Ergonomics; 5. Reliability; 6. Hygiene; 7. Material Strength; 8. Durability; 9. Affordance; 10. Dimensions; 11. Appearance; 12. Comfort of use. Those features were used to fill the Relationship Matrix, in order to define which of them were most important and more independent. In the Relationship Matrix of Relative Importance (Table 1), every cell should be filled with a numerical value (from 0 to 2), depending on how much the requirements of the rows are more or less important than the ones in the columns (e.g., comparing row 1 with column 2, the question is: is adaptability more important than the adjustability?) The scores are then assigned in this way:  
* 0--if the requirement of the row is more important than the one of the column,
* 1--if the requirement of the row and the one of the column are equally important,
* 2--if the requirement of the row is less important than the one of the column. After calculating the sum of all the values in each column, there was obtained a ranking of all the features; the ones with the highest ranks were reliability, material strength, adaptability, ergonomics and durability. These ones were considered as the most important features that should be well designed. Similarly, in the Relationship Matrix of Dependence/Independence (Table 2), every cell should be filled with a numerical value (from 0 to 9) depending upon how much the requirements of the rows are more or less dependent than the ones in the columns (e.g., comparing row 1 with columns 2: how much adaptability depends on adjustability?). The scores are then assigned in this way:  
* 0--if the requirement of the row is totally independent on the one of the column,
* 1--if the requirement of the row is not so dependent on the one of the column,
* 3--if the requirement of the row is very dependent on the one of the column,
* 9--if the requirement of the row is totally dependent on the one of the column. In this case, by calculating the sum of all the values in each column, there was revealed a classification of the most independent features and the first three ones were: adaptability, adjustability and material strength. Taking into account the first three characteristics of the first matrix and the first three by the second matrix, it is finally possible to draw up this list of project requirements:  
* Reliability
* Material Strength
* Adaptability