Hello,
I am trying to plot the braking distance graph for a vehicle braking where the speed "v" ranges from 0 to 373 km/h and the real friction coefficient "ux" is a function of the standing grip coefficient "u" and decays by 10% with each 110 km/h of speed gained. The other values are constants, "t"=total reaction time, "a"=slope angle [rad], "p"=atmospheric pressure, "cx"=longitudinal drag coeff., "cz"=vertical drag coeff. (in this case downforce), "ax"=frontal area in square metres, 'm'=vehicle mass in kg.
This code also computes the mean deceleration as well as braking times with/without accounting for t.
This is the working code for computing the braking distance under a non-variable grip coefficient:
v=0:373; td=0.5; ts=0.2; g=9.81; a=0; p=1.204;
cx=0.35; cz=-0.05; ax=1.77; m=1240; u=1.2;
t=td+ts;
vmax=373/3.6;
w=m*g;
c0=(u*cos(a))+sin(a);
c2=p*ax*(cx-u*cz)/(w*2);
s=(log(1+((v/3.6).^2)*(c2/c0)))/(2*c2*g);
S=(log(1+((v/3.6).^2)*(c2/c0)))/(2*c2*g)+t*(v/3.6);
d=g*(c0+c2*(vmax.^2))
dG=d/g
BD=(log(1+((vmax).^2)*(c2/c0)))/(2*c2*g)
TBD=BD+t*vmax
ts=vmax/d
Ts=t+ts
hold on, grid on
plot (v,s, 'r'); plot (v,S, 'k')
However the script accounting for ux cannot be represented in the same way:
ux=u*(1-(3.6*(v/3.6)/1100));
c0x=(ux*cos(a))+sin(a);
c2x=p*ax*(cx-ux*cz)/(w*2);
sx=(log(1+((v/3.6).^2)*(c2x/c0x)))/(2*c2x*g);
Sx=(log(1+((v/3.6).^2)*(c2x/c0x)))/(2*c2x*g)+t*(v/3.6);
dx=g*(c0x+c2x*(vmax.^2))
dGx=dx/g
BDx=(log(1+((vmax).^2)*(c2x/c0x)))/(2*c2x*g)
TBDx=BDx+t*vmax
tsx=vmax/dx
Tsx=t+tsx
hold on, grid on
plot (v,sx, 'm'); plot (v,S, 'b')
MATLAB prompts the following script: "Error using / Matrix dimensions must agree."
I'd be grateful if anyone would be kind enough to help me out with plotting this function. Thank you in advance!
