Ausarbeitung/experiment2.tex

   1 \chapter{Experiment 2: Movement Behaviour with Mean Correction}
   2 \todo{}
   3
   4 As presumed in Section \ref{exp1:results}, errors in the Roomba's movements
   5 could originate from imprecise measurement of the Roomba's internal sensors or
   6 in the Wiselib implementation. So a natural approach to correct this sort of
   7 errors would be to average the results for each data point from Experiment 1,
   8 find a function that fits the mean measured error depending of the
   9 target velocity and target distance or angle as well as possible, and then
  10 adapting either one of the target parameters so that the resulting movement
  11 would most likely be the desired target value. In this experiment however, only
  12 the target distance resp. the target angle was adjusted, while the velocity
  13 remained unadjusted.
  14
  15 Fitting the function\index{fit function} was done with \acs{GNU} R\index{GNU R}
  16 through the wrapper script \prog{graph.sh} which is explained in
  17 section~\ref{sec:impl:eval}. In this experiment, a 2-dimensional linear fit for
  18 the measured value was determined by the method of least squares, with target
  19 value (angle or distance) and velocity as input parameters. The fit function was
  20 then used in the algorithm to calculate the adapted target distance or angle.
  21
  22 \section{Setup}
  23 The hardware setup was exactly the same as in Experiment 1. However, in this
  24 experiment the application \prog{mean\_correction\_test} was used to measure
  25 data. It did exactly the same as the application from Experiment 1, except that
  26 it adapted the target value according to the method described above.
  27
  28 \section{Results}
  29 \begin{figure}[p!]
  30  \centering
  31  \includegraphics[width=\textwidth]{images/iz250flur_drive-mean_data.pdf}
  32  \caption{Behaviour with mean correction on laminated floor, straight drive
  33 tests}
  34 \end{figure}
  35 \begin{figure}[p!]
  36  \centering
  37  \includegraphics[width=\textwidth]{images/iz250flur_turn-mean_data.pdf}
  38  \caption{Behaviour with mean correction on laminated floor, turn tests}
  39 \end{figure}
  40 \begin{figure}[p!]
  41  \centering
  42  \includegraphics[width=\textwidth]{images/seminarraum_drive-mean_data.pdf}
  43  \caption{Behaviour with mean correction on carpet floor, straight drive
  44 tests}
  45 \end{figure}
  46 \begin{figure}[p!]
  47  \centering
  48  \includegraphics[width=\textwidth]{images/seminarraum_drive-mean_data.pdf}
  49  \caption{Behaviour with mean correction on carpet floor, turn tests}
  50 \end{figure}
  51
  52 results better than in experiment 1, very accurate for laminate floor, carpet
  53 floor more spread but still kind of in the middle and less deviation from ideal
  54 value.
  55 \todo{statistical values, stddev?}