Add second development cycle

content/case_experiment.tex

@@ -32,12 +32,7 @@ Splitting the initial design into features is done in the feature definition ste
 
 \section{First Development Cycle}
 \input{content/case_experiment_end-effector.tex}
-    \subsection{Feature Selection}
-    \subsection{Rapid Development}
-    \subsection{Variable Approach}
 
 \section{Second Development Cycle}
-    \subsection{Feature Selection}
-    \subsection{Rapid Development}
-    \subsection{Variable Approach}
+\input{content/case_experiment_scara.tex}
 

content/case_experiment_scara.tex

@@ -0,0 +1,106 @@
+%&tex
+    \subsection{Feature Selection}
+        The implementation of the end-effector proofed to be impractical.
+        This means that only two features are left.
+        The updated table in \autoref{tab:featurestab2} shows that the next step would be the SCARA.
+        The SCARA has a higher risk/time factor and covers more tests.
+        \begin{table}[]
+            \caption{}
+            \label{tab:featurestab2}
+            \begin{tabular}{|l|l|l|l|l|l|}
+                \hline
+                Feature      & Dependees   & Tests  & Risk   & Time    & Risk/Time  \\ \hline
+                SCARA        & -           & 3      & 40\%   & 10 days & 4          \\ \hline
+                End-effector & SCARA       & 2      & 60\%   & 8 days  & 7.5        \\ \hline
+                Carriage     & -           & 2      & 30\%   & 10 days & 3          \\ \hline
+            \end{tabular}
+        \end{table}
+
+    \subsection{Rapid Development}
+        At the end of this implementation the SCARA is able to write the first characters
+        This will be achieved by working through different levels of detail.
+        Where each level adds more detail to the model.
+        The levels that are implemented are as follow:
+        \begin{enumerate}
+            \item Basic kinematics model, no physics.
+            \item Basic physics model, ideal 2D physics.
+            \item Basic Motor behavior, 2D physics with non-ideal DC-motor.
+            \item Basic control law, path planning.
+            \item Advanced motor behavior, 2D physics with stepper motor behavior.
+            \item Advanced physics model, 3D physics with complex dynamics with Lie-algebra.
+            \item Marker lifting behavior, servo lifts marker of the board.
+        \end{enumerate}
+        This mainly describes the different level of physics detail.
+        Together with the physics model there will be a solid 3D CAD model.
+        The CAD model helps to check with dimensions and possible collisions of objects.
+
+        \subsubsection{Basics}
+            \begin{marginfigure}
+                    \centering
+                    \begin{tikzpicture}
+                            \tikzstyle{arrow} = [-latex,ultra thick]
+                    
+                    % draw roof
+                    \fill[pattern = north east lines] ($ (0,0) + (-1,0) $) rectangle ($ (0,0) + (1,0.5) $);
+                    \draw[thick] ($ (0,0.5) + (-1,0) $) -- ($ (0,0.5) + (1,0) $);
+                    
+                    %draw arm and joints
+                            \fill (0,0.5) circle (0.2);  
+                            \draw[thick] (0,0.5) to node[midway,right,draw=none] {$a$} (-1.5,3.5);  
+                            \fill (-1.5,3.5) circle (0.2); 
+                            \draw[thick] (-1.5,3.5) to node[midway,above,draw=none] {$b$}(1.51,4.26);		
+                            
+                            %draw mass
+                            \draw (1.7,4.32) circle (0.2) node {$m$};
+                            
+                            %draw arc
+                    %\draw[dashed,gray] (-1.5,3.5) -- ++(2.5,0);
+                    %\draw (1,0.5) arc (0:116:1cm) node[above,midway] {$\theta$};	
+
+                    %\draw [arrow] (c.south) -- +(0,-1cm) node[midway,right,draw=none] {$F_{g} = m \cdot g$};
+                    \end{tikzpicture}
+                    \caption{Basic kinematics of the SCARA}
+                    \label{fig:scaraarm}
+            \end{marginfigure}
+            The first four detail steps are just creating the basics dynamics of the SCARA as shown in \autoref{fig:scaraarm}
+            It start with the kinematics model that is used to test the forward and inverse kinematics of the design.
+            It gave a general idea of angles and arm lengths that are required in the design.
+            The second detail iteration adds the basic physics of the model.
+            This model was in the form of a double pendulum, with to powered joints.
+            The ideal motors in the joints made it that it could move with almost infinite speed.
+            To get a better idea of the forces in the model, the ideal motors are replaced with a beter motor model.
+            As the system did not operate with infinite gain anymore it the path planning was updated as well.
+            A simple PID controller was implemented to make SCARA follow a square path.
+            
+            Now that the model forms a basic with the non-ideal motors, basic physics and a controllaw, it can be used to make some estimates.
+            The model followed the required path in the specified amount out time.
+            With this, the minimum required torque could be calculated.
+            Which is then used to dimension the motors.
+
+        \subsubsection{Advanced Model}
+            The basic model contains all elementary components and detail can be added for different components.
+            The first step was to improve the motor models.
+            Up to now it was a primitive model with a source of effort, resistance and gyrator in series.
+            For the design it was decided to go with a stepper motor.
+            The advantage of a stepper motor is the holding torque, such that the motor can be forced in a certain angle.
+            With the new motors the controller was updated, to accommodate for the behavior of the steppers.
+
+            The next step was to upgrade the model to a full three dimensional dynamics.
+            Although the SCARA model itself is valid in only two dimensions, having the SCARA suspended from wires required the full dimensions.
+            The dynamics of the SCARA are based on a serial link structure \autocite{dresscher_modeling_2010}.
+            This allowed for a simple, yet quick implementation of the dynamics.
+
+        \subsubsection{3D modeling}
+            With a full dynamics model in 20-sim, the next step was to design the system in OpenSCAD.
+            Although 20-sim has a 3D editor, it is significantly easier to build components with OpenSCAD.
+            Furthermore, for prototyping the OpenSCAD objects can be exported for 3D printing.
+            The model made it possible to check component clearance and get an idea of size.
+            The model is shown in \autoref{fig:scad_carriage}.
+            \begin{figure}
+                \centering
+                \includegraphics[width=0.8\linewidth]{graphics/scad_carriage.png}
+                \caption{Rendered 3D model of the SCARA}
+                \label{fig:scad_carriage}
+            \end{figure}
+
+    \subsection{Variable Approach}