Add prototyping section

content/case_experiment_prototype.tex

@@ -1,15 +1,37 @@
-        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.
-        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}
+To ensure that the design method resulted in a functional system, a prototype will be build from the current state of the design.
+Although the development only implemented a very small portion of the full design, I determined that a prototype is more valuable than repeating the development cycle for the next feature.
+For the construction of the prototype \ac{ots}-parts are used as much as possible and the mechanical linkages of the SCARA will be printed.
+To write characters on a whiteboard, drivers and controlloop have to be implemented in software.
 
 
+\subsection{Construction}
+    The construction of the SCARA consists of a 3D printed mechanical structure that is actuated with stepper motors.
+    The type of stepper motor was already chosen during the development of the SCARA.
+    For the mechanical part I used OpenSCAD as CAD software, based on prior experience with the software.
+    As the inverse kinematics were already determined in basic model of the SCARA they could be easily parsed to the CAD software.
+    This allowed me to check for clearance between the mechanical parts, while repeating \autoref{test1}.
+    The test revealed that there was collision between some parts.
+    These collisions were resolved by adding a indentation and moving linkage and are shown in \autoref{fig:scad_clearance}
+    The configuration with the stepper motors, servo and marker is shown in \autoref{fig:scad_carriage}.
+    \begin{figure}
+        \centering
+        \includegraphics[width=0.8\linewidth]{graphics/scad_scara_circles.png}
+        \caption{CAD of the SCARA configuration, with the end-effector orientated in the lower left corner of the operating area. 
+        The configuration has been adapted at the two circled points, to resolve collisions in this orientation. 
+        An indentation was made to ensure that the arm could make the required corner.
+        Furthermore, the bottom linkage has been moved from above to below the actuated joints, as this linkage would otherwise collide with the end-effector.}
+        \label{fig:scad_clearance}
+    \end{figure}
+
+    \begin{figure}
+        \centering
+        \includegraphics[width=0.8\linewidth]{graphics/scad_carriage.png}
+        \caption{Rendered 3D model of the SCARA, including steppers, marker and servo.}
+        \label{fig:scad_carriage}
+    \end{figure}
+
+\subsection{Implementing Behavior}
+    Now with a physical SCARA, the last step is to implement the behavior.
+    The stepper motors are powered via a stepper controller.
+    The path planning for the SCARA and the operation of the stepper controller is implemented on a \ac{mcu}.
+

content/case_experiment_scara.tex

@@ -172,3 +172,4 @@
             Both options are not ideal, the first one does not allow a simple basic model and the second approach redoes work.
             The advantage of starting with 3D is that allows for a continuous development of one model, instead of switching the complete model.
 
+

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-Subproject commit e8129869df0b121e0b4aafe70ffbcab4183ec03b
+Subproject commit d67b00ea55a6274f292704af4eb068cc501d4f59