Ausarbeitung/experiment2.tex

   1 \chapter{Experiment 2: Movement Behaviour with Mean Correction}
   2 \todo{}
   3 \label{sec:exp2}
   4
   5 As presumed in Section \ref{exp1:results}, errors in the Roomba's movements
   6 could originate from imprecise measurement of the Roomba's internal sensors or
   7 in the Wiselib implementation. So a natural approach to correct this sort of
   8 errors would be to average the results for each data point from Experiment 1,
   9 find a function that fits the mean measured error depending of the
  10 target velocity and target distance or angle as well as possible, and then
  11 adapting either one of the target parameters so that the resulting movement
  12 would most likely be the desired target value. In this experiment however, only
  13 the target distance resp. the target angle was adjusted, while the velocity
  14 remained unadjusted.
  15
  16 Fitting the function\index{fit function} was done with \acs{GNU} R\index{GNU R}
  17 through the wrapper script \prog{graph.sh} which is explained in
  18 section~\ref{sec:impl:eval}. In this experiment, a 2-dimensional linear fit for
  19 the measured value was determined by the method of least squares, with target
  20 value (angle or distance) and velocity as input parameters. The fit function was
  21 then used in the algorithm to calculate the adapted target distance or angle.
  22
  23 \section{Setup}
  24 The hardware setup was exactly the same as in Experiment 1. However, in this
  25 experiment the application \prog{mean\_correction\_test} was used to measure
  26 data. It did exactly the same as the application from Experiment 1, except that
  27 it adapted the target value according to the method described above.
  28
  29 \section{Results}
  30 \begin{figure}[p!]
  31  \centering
  32  \includegraphics[width=\textwidth]{images/iz250flur_drive-mean_data.pdf}
  33  \caption{Behaviour with mean correction on laminated floor, straight drive
  34 movements}
  35 \end{figure}
  36 \begin{figure}[p!]
  37  \centering
  38  \includegraphics[width=\textwidth]{images/iz250flur_turn-mean_data.pdf}
  39  \caption{Behaviour with mean correction on laminated floor, turn movements}
  40 \end{figure}
  41 \begin{figure}[p!]
  42  \centering
  43  \includegraphics[width=\textwidth]{images/seminarraum_drive-mean_data.pdf}
  44  \caption{Behaviour with mean correction on carpet floor, straight drive
  45 movements}
  46 \end{figure}
  47 \begin{figure}[p!]
  48  \centering
  49  \includegraphics[width=\textwidth]{images/seminarraum_drive-mean_data.pdf}
  50  \caption{Behaviour with mean correction on carpet floor, turn movements}
  51 \end{figure}
  52
  53 results better than in experiment 1, very accurate for laminate floor, carpet
  54 floor more spread but still kind of in the middle and less deviation from ideal
  55 value.
  56 \todo{statistical values, stddev?}