mar/content/conclusion.tex

%&tex
\chapter{Conclusion}
\label{chap:conclusion}
    The goal of this thesis is to investigate if the design method by \textcite{broenink_rapid_2019} can be applied on a mechanical design.
    During the case study, the design method was used to design a whiteboard writer.
    The case study resulted in a working prototype of a subsystem.
    The experience and evaluation of the case study are used to answer the questions of \autoref{chap:introduction}.
    
    \emph{Which techniques of the design method can be applied in the development of hardware?}\\
    The design method in this thesis is split in two parts: the preliminary design and the detail design.
    In summary, the preliminary design is not suited for mechanical design.
    With the core of the problem being that the design method focusses on implementing the mechanical features separately from each other.
    However, the interconnection of the energy states makes the system tightly coupled.

    The detail design phase is a good technique for implementing a mechanical design.
    Provided that there is a basic model with all elementary components.
    All interfaces in the dynamics of the system constitute as power connections.
    A more detailed motor shall always output a torque or velocity. 
    This makes it easy to switch sub-models.

    %With the core of the problem being that it assumes that mechanical components can be implemented separately from each other.
    %This leads to implementation difficulties for each preliminary design step.
    %Another aspect that hinders the design flow are the dynamic states, because these states are tightly coupled.

    \emph{Which adaptations are required to create a design method that is suitable for the development of hardware?}\\
    The preliminary phase requires a full overhaul to be suitable for the development of hardware.
    The current approach is comparable with the waterfall-model.
    The waterfall-model focusses on avoiding design changes, as these become more expensive during the development process.
    But the modeling and simulation tools make changes to a dynamic system inexpensive.
    As changes are inexpensive and the system is tightly coupled an iterative design approach for the preliminary design phase is more beneficial.

    Some other lessons that could be drawn from the case study is that software and hardware require a radically different approach.
    The production of software starts with the first line of code, but the production of hardware starts when the first system comes from the production line.
    The costs of change for software is a directly related to the lost labor of developers.
    The hardware design is finished before production giving more room for change before big investments are made.

    \section{Recommendations}
   %    Although this research only focussed at the physical part of a \ac{CPS}, there are still some valuable recommendations for the overall design of a \ac{cps}.
   %    The 
        To improve the future development of a design method for \ac{cps} it is recommended to further investigate the following:
        \begin{itemize}
            \item State Analysis: Although this research focussed on the hardware, there is a clear suggestion that the difference in design approach depends on the type of state.
                Software is based on states in memory, which are often defined by the developer. Furthermore, these states only change when an instruction access that memory value.
                For a mechanical system, the energy states interact. How these states interact with each other depends on the definition of the state itself, not on a code instruction.
                Somewhere in the \ac{cps}, these states interconnect. And both sides require a different design approach, thus where do these interfaces fit in the design method.
            \item Software integration: Early in the case study it was clear that software would be an important part of the system. The current design method does not take the software integration into account.
                However, software has a crucial part in a \ac{cps}. From what moment in the development has, or can, the software to be taken into account?
            \item Design Team: A common note in the case study evaluation was the lack of interaction. Brainstorming about features, components and solutions could have improved the preliminary phase.
                However, a team could also be counterproductive due to miscommunication between within the team. To ensure the effectiveness of a design method it is important to develop an approach for team interaction.
        \end{itemize}