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plotting variables within function

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Marlon
Marlon 2023-6-12
评论： Walter Roberson 2023-6-12
Ran in:
Hi, so I'm trying to plot certain variables in my code, that are calculated in the function with state variables.
Plotting the state variables is working well but when I try to plot other Variables like Fwx over time I get an error saying
Unrecognized function or variable 'Fwx'.
Error in ZUSTANDSRAUM (line 63)
plot(t, Fwx); xlabel('t'); ylabel('Fwx'); % Plot von Fwx gegen t
Here's the code:
clear
close all;
clc;
%constant parameters:
m = 1700; % Fahrzeugmasse [kg]
lv = 1.2; % Abstand des Fahrzeugschwerpunkts zum Vorderachsmittelpunkt [m]
lh = 1.8; % Abstand des Fahrzeugschwerpunkts zum Hinterachsmittelpunkt [m]
iz = 500; % Trägheitsmoment um die Hochachse [kg*m^2]
cs = 10000; %Umfangssteifigkeit[N/°]
ca = 50000; %Schräglaufsteifigkeit[N/rad]
cx = 10000; %Reifenlängssteifigkeit
cy = 50000; %Seitetsteifigkeit
cw = 0.23; % CW Wert
pL = 1.2041; % Luftdichte [kg^m3]
Af = 0.3; %[Windanströmfläche]
Jv = 1.245; %[kgm^2]
Jh = 1.245; %[kgm^2]
r = 0.49; %m
%Eingangsgrößen
delta = deg2rad(0); %[Lenkwinkel°]
%Mav = 100; %Antriebsmoment [Nm]
Mah = 0;
Mbv = 0; %Bremsmoment [Nm]
Mbh = 0;
%Zeitbereich
tspan = [0 10];
%Anfangsbedingungen - Zustandsvektor
x =[0; % x(1): XV - KS X Richtung
0; % x(2): YV - KS Y Richtung
0; % x(3): PSI - Gierwinkel
70; % x(4): XV' - Geschwindigkeit in X Richtung [m/s]
0; % x(5): YV' - Geschwindigkeit in Y Richtung [m/s]
0; % x(6): PSI' - Giergeschwindigkeit
145.14; % x(7): pv' Winkelgeschwindigkeit Vorderes Rad
0; % x(8): ph' Winkelgeschwindigkeit hinteres Rad
204; % x(9): vFv,x Kraft Vorderreifen x-Richtung
0; % x(10): vFv,y Kraft Vorderreifen y-Richtung
0; % x(11): hFh,x Kraft Hinterreifen x-Richtung
0]; % x(12): hFh,y Kraft Hinterreifen y-Richtung
[t,x] = ode45(@(t,x) odefcn(m, lv, lh, iz, cs, ca, cx, cy, cw, pL, Af, Jv, Jh, r, delta, Mah, Mbv, Mbh,x,t),tspan,x);
subplot(4, 3, 1); plot(t, x(:,1)); xlabel('t'); ylabel('x(1): XV');
subplot(4, 3, 2); plot(t, x(:,2)); xlabel('t'); ylabel('x(2): YV');
subplot(4, 3, 3); plot(t, x(:,3)); xlabel('t'); ylabel('x(3): PSI');
subplot(4, 3, 4); plot(t, x(:,4)); xlabel('t'); ylabel('x(4): XV'' [m/s]');
subplot(4, 3, 5); plot(t, x(:,5)); xlabel('t'); ylabel('x(5): YV'' [m/s]');
subplot(4, 3, 6); plot(t, x(:,6)); xlabel('t'); ylabel('x(6): PSI'' - ');
subplot(4, 3, 7); plot(t, x(:,7)); xlabel('t'); ylabel('x(7): pv''');
subplot(4, 3, 8); plot(t, x(:,8)); xlabel('t'); ylabel('x(8): ph''');
subplot(4, 3, 9); plot(t, x(:,9)); xlabel('t'); ylabel('x(9): vFv,x');
subplot(4, 3, 10); plot(t, x(:,10)); xlabel('t'); ylabel('x(10): vFv,y');
subplot(4, 3, 11); plot(t, x(:,11)); xlabel('t'); ylabel('x(11): hFh,x');
subplot(4, 3, 12); plot(t, x(:,12)); xlabel('t'); ylabel('x(11): hFh,y');
Fwx =0.5*cw*pL*Af*x(:,4).*((x(:,4)).^2+(x(:,5)).^2).^0.5;
plot(t, Fwx); xlabel('t'); ylabel('Fwx'); % Plot von Fwx gegen t
function dxdt = odefcn(m, lv, lh, iz, cs, ca, cx, cy, cw, pL, Af, Jv, Jh, r, delta, Mah, Mbv, Mbh,x,t)
% Vektorkombination
Mav=15*t;
rv = [x(4)-lv*x(6)+sin(x(3));
x(5)+lv*x(6)*cos(x(3));
0];
vrv = [cos(x(3)+delta) sin(x(3)+delta) 0;
-sin(x(3)+delta) cos(x(3)+delta) 0;
0 0 1]*rv;
rh = [x(4)-lh*x(6)+sin(x(3));
x(5)+lh*x(6)*cos(x(3));
0];
hrh = [cos(x(3)) sin(x(3)) 0;
-sin(x(3)) cos(x(3)) 0;
0 0 1]*rh;
% Schlupfwerte
% Längsschlupf
sv = (r * x(7) - rv(1)) / (max(abs(r * x(7)), abs(vrv(1))) + 1e-10);
sh = (r * x(8) - rh(1)) / (max(abs(r * x(8)), abs(hrh(1))) + 1e-10);
% Schräglaufschlupf
av = -(vrv(2) / (abs(x(7)) + 1e-10));
ah = -(hrh(2) / (abs(x(8)) + 1e-10));
% Reifenkräfte
A=1.12;
C=0.625;
D=1;
n=0.6;
K=46;
d=5;
B = (K/d)^(1/n);
%vFvxstat = cs*sv;
%vFvystat = ca*av;
%hFhxstat = cs*sh;
%hFhystat = ca*ah;
vFvxstat =(m/4)*sign(sv).*(A.*(1-exp(-B*abs(sv)))+C*sv.^2-D*abs(sv));
vFvystat = (m/4)*sign(av).*(A.*(1-exp(-B*abs(av)))+C*av.^2-D*abs(av));
hFhxstat = (m/4)*sign(sh).*(A.*(1-exp(-B*abs(sh)))+C*sh.^2-D*abs(sh));
hFhystat = (m/4)*sign(ah).*(A.*(1-exp(-B*abs(ah)))+C*ah.^2-D*abs(ah));
% Radkraft Hinterachse
Fhx = cos(x(3))*x(11)-sin(x(3))*x(12);
Fhy = sin(x(3))*x(11)+cos(x(3))*x(12);
% Radkraft Vorderachse
Fvx = cos(x(3) + delta)*x(9)-sin(x(3) + delta)*x(10);
Fvy = sin(x(3) + delta)*x(9)+cos(x(3) + delta)*x(10);
% Luftwiderstand
Fwx =0.5*cw*pL*Af*x(4)*((x(4))^2+(x(5))^2)^0.5;
Fwy =0.5*cw*pL*Af*x(5)*(x(4)^2+(x(5))^2)^0.5;
dxdt = zeros(12,1);
dxdt(1) = x(4); %Geschwindigkeit x-Richtung
dxdt(2) = x(5); %Geschwindigkeit y-Richtung
dxdt(3) = x(6); %Gierbeschleunigung
dxdt(4) = (m^-1)*(Fvx+Fhx-Fwx); %Beschleunigung x-Richtung
dxdt(5) = (m^-1)*(Fvy+Fhy-Fwy); %Beschleunigung y-Richtung
dxdt(6) = ((iz^-1)*lv*sin(delta)*x(9)+cos(delta)*x(10)-lh*x(12)); %Gierbeschleunigung
dxdt(7) = (1/Jv)*(Mav-Mbv*sign(x(7))-r*x(9)); %Radwinkelgeschwindigkeit VA
dxdt(8) = (1/Jh)*(Mah-Mbh*sign(x(8))-r*x(11));%Radwinkelgeschwindigkeit HA
dxdt(9) = (cx*(r*x(7))/cs)*(vFvxstat-x(9)); %Radkraft VA X-Richtung
dxdt(10)= (cy*(r*x(7))/ca)*(vFvystat-x(10)); %Radkraft VA Y-Richtung
dxdt(11)= (cx*(r*x(8))/cs)*(hFhxstat-x(11)); %Radkraft VA X-Richtung
dxdt(12)= (cy*(r*x(8))/ca)*(hFhystat-x(12)); %Radkraft VA Y-Richtung
end

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回答（1 个）

Torsten
Torsten 2023-6-12
Recalculate Fwx from the solution (see above).
  4 个评论
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Marlon
Marlon 2023-6-12
Is there a way to pass variables outside the Function, that I don't have every calculation of the Variables I want to plot two times in the code?
Walter Roberson
Walter Roberson 2023-6-12
@Marlon
Yes, there are ways. However, in the context of ode functions, it is almost always the wrong thing to do.

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