Added functions to show dependencies more clearly. Added descriptions. TODO:...

Added functions to show dependencies more clearly. Added descriptions. TODO: update intSignals function.

+math/IntSignals.m

-function data = IntSignals(data,index)
+function data = intSignals(data,index)
 
 if index == 1
     data.rG = nan(data.N,3);

+math/calculateSteps.m

+%% This function calculates the step parameters of interest.
+
+% input:
+% dataStruct - containing identified steps and acc/gyro data.
+
+% output:
+% dataStruct - containing calculated FPA.
+
+function dataStruct = calculateSteps(dataStruct)
+
+% Number of steps is 1 smaller as it should end with foot contact.
+steps = 1:(length(dataStruct.tMiddle)-1);
+
+% Loop over all steps.    
+for iStep = steps
+
+    % Pre-allocate space for the FPA values.
+    if iStep == 1
+        dataStruct.FPA = nan(length(steps),1);
+    end
+
+    % Integrate the signals to obtain the FPA within a step.
+    dataStruct = math.intSignals(dataStruct, iStep);
+
+end
+end
\ No newline at end of file

+math/correctSteps.m

+%% This function makes sure that the steps start with contact and end with
+% a full contact phase.
+
+% input:
+% dataStruct - containing tStart, tEnd vectors to correct.
+
+% output:
+% dataStruct - with correct start and end indexes.
+
+function dataStruct = correctSteps(dataStruct)
+
+
+% Correct for wrong first step.
+if dataStruct.tEnd(1) < dataStruct.tStart(1)
+    dataStruct.tEnd(1) = [];
+end
+ 
+% End with a full step.
+if dataStruct.tEnd(end) < dataStruct.tStart(end)
+    dataStruct.tStart(end) = [];
+end
+
+% Get the middle of contact phases for later calculations.
+dataStruct.tMiddle = floor((dataStruct.tStart(2:end) + ...
+    dataStruct.tEnd(1:end-1))/2);
+
+end
\ No newline at end of file

+math/initOrien.m

@@ -9,8 +9,14 @@
 % rmy - error of the rotation around y axis.
 % rmz - error of the rotation around x axis.
 % accOffsetR - Offset of the acceleration data.
+% tStart - start time of static parts.
+% tEnd - end time of static parts.
+% contactVector - boolean vector containing indicators of contact.
 
-function [rotMatrix, rmy, rmz, accOffsetR]=initOrien(data)
+function outStruct = initOrien(data)
+
+% Pre-allocate structure
+outStruct = struct();
 
 % cut-off frequency of the filter.
 fCutoff = 2;
@@ -18,23 +24,26 @@ fCutoff = 2;
 % 2nd order low-pass butterworth filter to get the relevant motion data.
 % Implement as filtfilt due to no realtime constraints.
 [Bf, Af] = butter(2, (2 * fCutoff / data.fs));
-filtAcc = filtfilt(Bf, Af, data.acc); 
-filtGyr = filtfilt(Bf, Af, data.gyr);
+outStruct.filtAcc = filtfilt(Bf, Af, data.acc); 
+outStruct.filtGyr = filtfilt(Bf, Af, data.gyr);
 
 %% Step detection using the zero velocity update.
-[tStart, tEnd, contactVector] = math.zvt(filtAcc,filtGyr, data.fs);
+[outStruct.tStart, outStruct.tEnd, outStruct.contactVector] = math.zvt(outStruct.filtAcc,outStruct.filtGyr, data.fs);
+
+% Correct the calculated steps.
+outStruct = math.correctSteps(outStruct);
 
 % Find the Static and Dynamic parts of the calibration trial.
-staticPart = floor(0.2*tStart):floor(0.8*tStart);
-steps = find(diff(contactVector));
-if contactVector(1) == 1
+staticPart = floor(0.2*outStruct.tStart):floor(0.8*outStruct.tStart);
+steps = find(diff(outStruct.contactVector));
+if outStruct.contactVector(1) == 1
     steps(1) = [];
 end
 dynamicPart = steps(1):steps(6);
 
 % Determine bias and subtract it.
-gyroBias = mean(data.gyr(staticPart,:));
-gyroNoBias = data.gyr - gyroBias;
+outStruct.gyroBias = mean(data.gyr(staticPart,:));
+gyroNoBias = data.gyr - outStruct.gyroBias;
 
 % Obtain the perpendicular walking direction principal component.
 yAxis = pca((gyroNoBias(dynamicPart,:)-mean(gyroNoBias(dynamicPart,:))));
@@ -51,16 +60,16 @@ xas = cross(normYaxis',zaxis)/norm(cross(normYaxis',zaxis));
 tzt = cross(xas,normYaxis)/norm(cross(xas,normYaxis));
 
 % Calculate the errors of the axes with respect to being perpendicular.
-rmz = sqrt((tzt-zaxis).^2);
+outStruct.rmz = sqrt((tzt-zaxis).^2);
 txt = cross(zaxis,xas)/norm(cross(zaxis,xas));
-rmy = sqrt((txt-normYaxis').^2);
+outStruct.rmy = sqrt((txt-normYaxis').^2);
 
 % the rotation matrix  is obtained by adding the three directions together.
-rotMatrix = inv([xas',normYaxis,tzt']);
+outStruct.rotMatrix = inv([xas',normYaxis,tzt']);
 
 % Determine acc offset (gravity)
 accOffset = mean(data.acc(staticPart,:));
 
 % Rotate acc offset to foot frame.
-accOffsetR = (rotMatrix*accOffset')';
+outStruct.accOffsetR = (outStruct.rotMatrix*accOffset')';
 end
\ No newline at end of file

+math/zvt.m

 %% Function to determine when the foot is stationary on the floor.
 % inputs:
-% acc - Nx3 matrix with acceleration values.
-% gyr - Nx# matrix with gyroscope values.
+% acc - Nx3 matrix with acceleration values (in m/s^2).
+% gyr - Nx# matrix with gyroscope values (in deg/s).
 
 % outputs:
 % tStart - indexes of initial contacts.

Main.m

@@ -22,9 +22,14 @@ for i = 3:length(subjectFolders)
     for j = 1:length(trialFiles)
         currentPath = [trialFiles(j).folder '\' trialFiles(j).name];
 
-        trialName = ['trial_' extractBefore(trialFiles(j).name, '.csv')];
+        trialName = strrep(['trial_' extractBefore(trialFiles(j).name, '.csv')], ' ','_');
 
         % Store the data in a useable format.
         dataStruct.(subjectFolders(i).name).(trialName) = readDotCsv(currentPath);
+
+        % calculate all values for each step.
+        dataStruct.(subjectFolders(i).name).(trialName) = ...
+            math.calculateSteps(dataStruct.(subjectFolders(i).name).(trialName));
+
     end
 end
\ No newline at end of file

getCalibration.m

@@ -27,13 +27,12 @@ function dataStruct = getCalibration(filePath)
         end
 
         % Determine the calibration orientation.
-        [dataStruct.(trialName).calibration.Rcal, ...
-            dataStruct.(trialName).calibration.rmy, ...
-            dataStruct.(trialName).calibration.rmz, ...
-            dataStruct.(trialName).AccOffsetR] = ...
+        dataStruct.(trialName).calibration = ...
         math.initOrien(dataStruct.(trialName));
 
+        
 
+        
 
     end
 

readDotCsv.m

@@ -14,6 +14,9 @@ function dataStruct = readDotCsv(filePath)
     dataStruct.mag = table2array(currentData(:,{'Mag_X', 'Mag_Y', 'Mag_Z'}));
     dataStruct.time = table2array(currentData(:,'SampleTimeFine')- ...
         currentData(1,'SampleTimeFine'))/1000000;
+
+    % Calculate the magnitic norm and sample frequency
+    dataStruct.magNorm = sum(dataStruct.mag.^2, 2);
     dataStruct.fs = round(1/(dataStruct.time(2) - dataStruct.time(1)));
 
 end
\ No newline at end of file