Creating a loop of a script

Hi,

I need to loop a script but i dont know how with using the for function

If i copy the script down it will continue on and work but this isn't very productive

The script is:

t_step=0.1
s_step=0.5 % Distance step of 0.5m
s_Zero=0
s=s_Zero+s_step
t=0
v_Zero=v_Lat
a=0.1; % Long Acceleration
% Loop starts Here
v=v_Zero+(a*t_step);
Tractive_Force_Tyre=mu_Long*((2.006*v*v*wdR)+(g*m*wdR)+(m*a*H/L)); % Zero Acceleration
if v<Max_First
    Tf=Tf_First;
elseif (Max_First<v) && (v<Max_Second)
    Tf=Tf_Second;
elseif (Max_Second<v) && (v<Max_Third)
    Tf=Tf_Third;
elseif (Max_Third<v) && (v<Max_Fourth)
    Tf=Tf_Fourth;
elseif (Max_Fourth<v) && (v<Max_Fifth)
    Tf=Tf_Fifth;
else (Max_Fifth<v) && (v<Max_Sixth)
    Tf=Tf_Sixth;
end
if Tractive_Force_Tyre>Tf;
    disp('Engine Limited');
    a_end=Tf/m;
else Tf>Tractive_Force_Tyre;
    disp('Traction Limited'); 
    a_end=Tractive_Force_Tyre/m;
end
v_Zero=v;
s_Zero=s;
a=a_end;
t_step=((sqrt((2*a.*s)+(v_Zero^2))-v_Zero)/a);
v=v_Zero+(a*t_step);
t=t+t_step;
s=s_step+s;
% Loop Finish Here

[dpb]

Use the {}Code button to format code...highlight and then click -- or, if you simply indent two spaces, subsequent paragraph will follow. It's a nuisance TMW built the forum defaults to use "line-wrap on" in a code forum, but they can't seem to or don't want to fix it... :(

[dpb]

What have you tried? For what condition do you want to loop? It would seem likely that while might be more suitable than for here to the overall time.

[Conor Hardiman]

I have tried a for and while loop,

However i'm not sure if the syntax is correct.

Do you have a suggestion on the while loop syntax for this?

Thank you for your reply

Answer 1

[Jan]

I do not understand "loop in back to the start t recalculate for the new values of a and s."

To create a loop start with defining, what should be changed fro iteration to iteration. Perhaps you want:

for t = 0:t_step:t_end
  ... your code
end

with a matching definition of t_end. Please try this and explain the occurring problems. This might help to get a better understanding of your problem.

Answer 2

[John BG]

Hi Conor

lower_lim=.001; % avoid null division
gear=[lowerLim Max_First Max_Second Max_Third Max_Fourth Max_Fifth Max_Sixth upper_lim]
Tf=gear(min(find(v/gear)<1))

then you can proceed with the Tractive_Force_Tyre sorting with obtained Tf threshold above

if Tractive_Force_Tyre>Tf;
    disp('Engine Limited');
    a_end=Tf/m;
else Tf>Tractive_Force_Tyre;
    disp('Traction Limited'); 
    a_end=Tractive_Force_Tyre/m;
end
..

if you find this answer useful would you please be so kind to consider marking my answer as Accepted Answer?

To any other reader, if you find this answer useful please consider clicking on the thumbs-up vote link

thanks in advance

John BG

<mailto:[e-mail] [e-mail]>

[Conor Hardiman]

Hi John,

The code I presented works however i need to loop in back to the start t recalculate for the new values of a and s.

Do you have any thoughts on this?

Thank you for your reply

[John BG]

Mr Connor

After a bit of guessing on not supplied parameters got your loop to spin,

since the many guessed values, can't tell if it's the Columbia taking off or a pop-corn jumping off the pot.

Please note, not plotting s v a, but the logged values in respective vectors vs vv va:

.

.

Also note the distance is also plot, but it's stuck on x axis.

quick-fix:

.

    clear all; clc
    mu_Long=0.001  % whatever friction or elasticity coeff it is
    wdR=0.001   % please define this other coeff
    g=9.81  % m/s^2 sea level, Earth
    m=.5 % test mass
    H=.5   % chassis distance to road surface? feet? metres??
    L=1;    % parking pillar?

    Max_First=.1
    Max_Second=.5
    Max_Third=1
    Max_Fourth=1.5
    Max_Fifth=2
    Max_Sixth=2.5
    upper_lim=3

    dt=0.1
    ds=0.5 % Distance step of 0.5m
    s_Zero=0
    v_Zero=0 %v_Lat

    lowerLim=.001; % avoid null division in gear

    vs=s_Zero   % space start value
    vv=v_Zero     % velocity start value

    vs=s_Zero+ds                    % init log vector vs
    a0=0.1;
    vv=[v_Zero+(a0*dt)];                     % init log vector vv
    va=.1

    for t=0:dt:60

    a =va(end)  % read a
    v=vv(end)  % read v

    Tractive_Force_Tyre=mu_Long*((2.006*v*v*wdR)+(g*m*wdR)+(m*a*H/L));                                              % obtain Tractive_Force_Tyre     Zero Acceleration

    gear=[lowerLim Max_First Max_Second Max_Third Max_Fourth Max_Fifth Max_Sixth upper_lim];
    Tf=gear(min(find(v./gear)<1));                                                               % obtain Tf from Tractive_Force_Tyre

    if Tractive_Force_Tyre>Tf;                                                                      % obtain a, a_end removed
        disp('Engine Limited');
        a=Tf/m;
    else Tf>Tractive_Force_Tyre;                   % if satured acceleration then a_end is not used, must be used
        disp('Traction Limited'); 
        a=Tractive_Force_Tyre/m;
    end

    s=vs(end)   % read
    s=ds+s;    % update log vector
    vs=[vs s]     % save
    % v_Zero=v;
    % s_Zero=s;
    % a=a_end;

    a=((sqrt((2*a.*s)+(v_Zero^2))-v_Zero)/dt);  % update a
    va=[va a]    % save a

    v=v+(a*dt);% update v
    vv=[vv v]      % save v

    % v=v_Zero
    % t=t+dt;

    end  % LOOP ends here

hold all;plot(vs) % distance
plot(vv)   % velocity
plot(va)   % acceleration
grid on

since I got it to spin, the loop, I kindly ask if you would consider marking my answer as accepted answer to your question by clicking on the blue button you should see, top left corner?

Appreciating time and attention

regards

John BG

<mailto:[e-mail] [e-mail]>