# Design of Cognitive Assistance Systems in Manual Assembly Based on Quality Function Deployment
## 4 Conceptual Adaptation of the QFD Method
### A New Proposed Conceptual Approach: Cognitive Assistance System-QFD  
The CAS-QFD method is based on six phases and step-by-step application (Figure 3). The approach is based on QFD derivatives, such as the software-QFD, process-QFD and service-QFD, as proposed by the authors of Refs. [102, 103, 104, 105, 106, 107, 108], and our novel conceptual approach [109].  
In the first phase, the overall goals and future challenges of the company are identified. It is important to understand these to be able to make the later weightings and decisions. The material flow and the production IT-systems inside the company's IT landscape are also considered. Since the production system, assembly configuration and their workers (experience level, age, preferences, etc.) are important for the design of the assistance functions and hardware, they are also analyzed. Finally, the project definition is created.  
For the design of an assistance system, the process in which the assistance functions are provided should first be analyzed, because of strong interrelationships, in second phase. In the sense of a process-QFD, requirements for the assembly process demanding assistance and the specific assembly tasks could be integrated and correlated in the first phase. The requirements of the assembly workers should also be included at this stage. The objective is to identify which requirements are related to which process steps and in what context so that an initial understanding of the assembly process is developed.  
In the third phase, suitable assistance functions are identified for the prioritized work tasks that need to be optimized. In this process, specific requirements of the workers can be identified and considered in the design of the assistance functions. In this way, the most important parts of the assembly process can be determined for optimization with the relevant assistance functions (assistance level).  
In the fourth phase, suitable hardware components can be defined for the specific assistance functions. This involves the human-assistant interaction. Furthermore, the interrelationships between the hardware components should be considered. The user requirements can again be considered in this phase for the design.  
In the fifth phase, the favored product variant is prototypically built and manually tested. This allows hypotheses to be validated and incremental changes to be performed before the system is implemented in the sixth phase, where it is finally evaluated and transferred into operation. A retrospective on the collaboration and the quality of the results concludes the project. The participation of the workers is proposed from phase two to the final realization.  
Figure 3: Proposed method: cognitive assistance system-QFD (CAS-QFD).  
The phases and the included steps should not be understood as a pure assessment tool. Instead, with the help of the developed logic for the design of cognitive assistance systems, it should offer the possibility of finding suitable alternatives through iterations of multiple trials. For this purpose, the steps can also be executed in a different order or can even be examined in parallel to each other.