Error using plot, vectors must be of the same length

I know this basically means that the two outputs are of different vector lengths so cant be plotted against each other, however i am not sure how to fix this in my coding, shown below. Thanks in advance for any advice!

R=input('Enter the radius of the turn > '); chim=input('Enter the angle of the turn > '); vf=input('Enter the velocity of the vehicle > '); %tmax=input('Enter the total manoeuvre time > '); dt=input('Enter the time increment for the discretisation > ');

chidm=vf/R; k=0.15; t1=2*k*((chim)/(chidm)); t2=t1+(2*R*chim*(1-(2*k)))/(2*vf); tmax=360; a1=(-2*chidm)/(t1^3); b1=3*chidm/(t1^2); a3=(2*chidm)/(tmax-t2)^3; b3=(-3*(t2+tmax)*chidm)/(tmax-t2)^3; c3=(6*t2*tmax*chidm)/(tmax-t2)^3; d3=chidm-((chidm*(3*tmax-t2)*t2^2)/(tmax-t2)^3);

global t mpts t=0 : dt : tmax; mpts=length(t);

if t>=0 & t<=t1 chid=a1*t.^3+b1*t.^2; chi=(1/4)*a1*t.^4+(1/3)*b1*t.^3; elseif t1<t & t<t2 chid=chidm; chi=chidm*t; elseif t2<=t & t<=tmax chid=a3*t.^3+b3*t.^2+c3*t+d3; chi=((1/4)*a3*t.^4)+((1/3)*b3*t.^3)+((1/2)*c3*t.^2)+(d3*t); end

plot(t,chid),xlabel('t (s)'),ylabel('chid (deg/s)')

Answer 1

[Thorsten]

Use a loop to determine the chid and chi values for different t

tall = t;

for i=1:numel(tall)
  t = tall(i);
  if t>=0 & t<=t1
    chid(i)=a1*t.^3+b1*t.^2;
    chi(i)=(1/4)*a1*t.^4+(1/3)*b1*t.^3;
  elseif t1<t & t<t2
    chid(i)=chidm;
    chi(i)=chidm*t;
  elseif t2<=t & t<=tmax
    chid(i)=a3*t.^3+b3*t.^2+c3*t+d3;
    chi(i)=((1/4)*a3*t.^4)+((1/3)*b3*t.^3)+((1/2)*c3*t.^2)+(d3*t);
  end
end

[Sean10]

Yes that makes sense thanks for the reply! It still isnt quite producing the expected result i think i have to re-calculate my values for t1,t2 and tmax. But that solves the plotting issue! Thanks again.

Answer 2

[Image Analyst]

Use the debugger: http://blogs.mathworks.com/videos/2012/07/03/debugging-in-matlab/

Then you'll be able to find out why t and chid are different lengths.

Also, read this: http://www.mathworks.com/matlabcentral/answers/13205-tutorial-how-to-format-your-question-with-markup

[Sean10]

Thanks for the heads up with the formatting. Also thanks for the video i'll check it out now!