cycle(cycle1,deltat,name)

function[cycle2] = cycle(cycle1,deltat,name)
%creates a drive cycle object (class 'cycle') starting from 
%cycle1, which is the path to an excel file with 3 columns
%existing of
%       time in s in column 1 
%       speeds in km/h in column2
%       slope in % in column3
%deltat is the required time step to get a good idea of the speed and slope changes during the drive cycle.
%typical value is 0.5s.
%name should be the name of the cycle which will be used for further processing
%The output cycle is an object with 5 fields
%   cycle.t=times in s
%   cycle.v=speeds in km/h
%   cycle.s=slopes in %
%   cycle.a=accelerations in m/s^2
%   cycle.dt=time step in s

if nargin == 0
    cycle2.t=[];
    cycle2.v=[];
    cycle2.s=[];
    cycle2.a=[];
    cycle2.dt=[];
    cycle2.name=[];
    cycle2=class(cycle2,'cycle');
elseif isa(cycle1,'cycle')
   cycle2 = cycle1;
else
    cycle1=xlsread(cycle1);
    [a b]=size(cycle1);
end

if b~=3
    error('wrong input type for first argument, the excel file should contain 3 columns (time[s],speed[km/h],slope[%]')
else
dt=deltat;
%times where speed or slope changes
tc=cycle1(:,1);
%speedlist
vc=cycle1(:,2)/3.6;
%slopelist
slopec=cycle1(:,3);
tmax=tc(length(tc));
time=0:deltat:tmax;
for i=1:length(tc)-1
    ac(i)=(vc(i+1)-vc(i))/(tc(i+1)-tc(i)); 
end

%opstellen snelheidsprofiel-hellingsprofiel ifv de tijd
k=1;
for i=1:length(tc)-1
while k<=length(time)
    if time(k)<=tc(i+1)
    speed(k)=3.6*(vc(i)+ac(i)*(time(k)-tc(i)));
    acc(k)=ac(i);
    slope(k)=slopec(i);
    k=k+1;
    else
    break
end
end
end
cycle2.t=time.';
cycle2.v=speed.';
cycle2.s=slope.';
cycle2.a=acc.';
cycle2.dt=dt.';
cycle2.name=(name').';
cycle2=class(cycle2,'cycle');
end