| @@ -1,10 +1,8 @@ | |||||
| %&tex | %&tex | ||||
| \chapter{Case Study: Evaluation} | \chapter{Case Study: Evaluation} | ||||
| \label{chap:case_evaluation} | \label{chap:case_evaluation} | ||||
| \section{Time Investment} | \section{Time Investment} | ||||
| Prior to each step in the development I made an estimation on the workload of that particular step. | |||||
| Prior to each step in the development, I made an estimation on the workload of that particular step. | |||||
| In \autoref{fig:time_spend} the planned and spend time on each step is plotted next to each other. | In \autoref{fig:time_spend} the planned and spend time on each step is plotted next to each other. | ||||
| Five of these steps were completed in the planned number of days. | Five of these steps were completed in the planned number of days. | ||||
| However, three steps required more time than expected. | However, three steps required more time than expected. | ||||
| @@ -18,20 +16,26 @@ | |||||
| \caption{Overview of the planned and spend number of days for each step during the case study.} | \caption{Overview of the planned and spend number of days for each step during the case study.} | ||||
| \label{fig:time_spend} | \label{fig:time_spend} | ||||
| \end{figure} | \end{figure} | ||||
| Furthermore, there is a significant difference between the planned number of days of the between the development cycles. | |||||
| Furthermore, there is a significant difference between the planned number of days for both development cycles. | |||||
| Prior to the first development cycle I was not confident about the feasibility of the end-effector implementation. | Prior to the first development cycle I was not confident about the feasibility of the end-effector implementation. | ||||
| Based on that, I decided to spend about three days on basic model of the end-effector to gain more information. | |||||
| These three days let me to the conclusion that the end-effector was not feasible for this case study. | |||||
| The second development cycle was significantly more feasible so I planned to spend two and a half week on the development. | |||||
| This development was also three days for the basic model and another two weeks for the additional levels of detail. | |||||
| Based on that, I decided to spend about three days on the basic model of the end-effector to collect more information. | |||||
| This let me to the conclusion that the end-effector was too time-consuming for this case study. | |||||
| For the second cycle, I also planned three days to create the basic model. | |||||
| This time, the basic model was finished within a couple of hours. | |||||
| Based this early success and prior experience, I planned an additional two weeks of development time for this cycle. | |||||
| To create a functional prototype, writing software was unavoidable, even though it was not part of the design plan. | |||||
| However, the time required to get to a basic software implementation too substantial to keep it out of the evaluation. | |||||
| Especially when I take the quality and evaluation overhead in account. | |||||
| The dynamic model was build up with different levels of detail including documentation for each level. | |||||
| Furthermore, between the levels I also did the evaluation of the design process. | |||||
| For the software, I skipped documentation and evaluation, as it would not contribute to the case study. | |||||
| The code quality of the software is decent in my opinion but significantly lower than the quality of the dynamic models. | |||||
| Although not directly part of the design method, I did build a prototype. | |||||
| This consisted of acquiring and assembling the hardware, and writing software. | |||||
| Acquiring and assembling the hardware took about two days. | |||||
| This was mainly due to CoViD-19 restrictions which made part ordering and printing more challenging. | |||||
| Without these restrictions I think it would it would be a day of work. | |||||
| However, the time required to get the software to a viable state was four weeks. | |||||
| Even though, the focus was not on the software, this timespan of four weeks is too significant to ignore. | |||||
| Especially when the software is compared to the developed models. | |||||
| In total I build eight competent models: a CAD drawing, one kinematics model, three 2D models and three 3D models. | |||||
| Each of these models includes documentation and an evaluation of the design process. | |||||
| The software, on the other hand, is in a bare minimum state; I skipped documentation and evaluation; and the code quality relatively low. | |||||
| Still, the software was more time consuming than the hardware modeling and development. | |||||
| \section{One-man development team} | \section{One-man development team} | ||||
| The case study was performed by me, as a single developer. | The case study was performed by me, as a single developer. | ||||
| @@ -46,3 +50,14 @@ | |||||
| The social interaction within a design team stimulates this documenting process as it improves the recall and interpretation of information. | The social interaction within a design team stimulates this documenting process as it improves the recall and interpretation of information. | ||||
| It also improves the judgement and selection between design alternatives \autocite{lamb_221_2008}. | It also improves the judgement and selection between design alternatives \autocite{lamb_221_2008}. | ||||
| \section{Switching Modelling Language} | |||||
| The initial idea of the development was to start with a basic model and extend that model by adding more detail. | |||||
| Meaning that one design and one model would develop in parallel with each other. | |||||
| However, the development of the SCARA resulted in four major model versions. | |||||
| The basic model started with a kinematics model. | |||||
| To take the physics of the design into account, a 2D dynamics model was created. | |||||
| Multiple steps of detail into the development, the 2D model was not adequate anymore. | |||||
| Therefore, the design was remodeled with 3D physics. | |||||
| Although this 3D physics model was able to implement the dynamic behavior, the modeling language was not suitable to design the shape of the mechanical components. | |||||
| Resulting in a fourth model which represents the mechanical component design, in the form of a CAD drawing. | |||||