汽车理论课后作业matlab编程详解带注释.docx
《汽车理论课后作业matlab编程详解带注释.docx》由会员分享,可在线阅读,更多相关《汽车理论课后作业matlab编程详解带注释.docx(14页珍藏版)》请在冰豆网上搜索。
![汽车理论课后作业matlab编程详解带注释.docx](https://file1.bdocx.com/fileroot1/2022-11/16/cae770a5-4108-4061-b795-48e67dc3dc53/cae770a5-4108-4061-b795-48e67dc3dc531.gif)
汽车理论课后作业matlab编程详解带注释
1.3matlab程序:
(1)
%驱动力-行驶阻力平衡图
%货车相关参数。
m=3880;
g=9.8;
nmin=600;
nmax=4000;
G=m*g;
ig=[5.562.7691.6441.000.793];y=0.85;r=0.367;f=0.013;CdA=2.77;i0=5.83;
L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;
n=600:
10:
4000;
%发动机转数转换成汽车行驶速度。
ua1=0.377*r*n/ig
(1)/i0;
ua2=0.377*r*n/ig
(2)/i0;
ua3=0.377*r*n/ig(3)/i0;
ua4=0.377*r*n/ig(4)/i0;
ua5=0.377*r*n/ig(5)/i0;
%计算各档位驱动力。
Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4;
Ft1=Tq*ig
(1)*i0*y/r;
Ft2=Tq*ig
(2)*i0*y/r;
Ft3=Tq*ig(3)*i0*y/r;
Ft4=Tq*ig(4)*i0*y/r;
Ft5=Tq*ig(5)*i0*y/r;
%计算行驶阻力。
Fz1=m*g*f+2.77*ua1.^2/21.15;
Fz2=m*g*f+2.77*ua2.^2/21.15;
Fz3=m*g*f+2.77*ua3.^2/21.15;
Fz4=m*g*f+2.77*ua4.^2/21.15;
Fz5=m*g*f+2.77*ua5.^2/21.15;
%驱动力-行驶阻力平衡图。
plot(ua1,Ft1,ua2,Ft2,ua3,Ft3,ua4,Ft4,ua5,Ft5,ua1,Fz1,'k',ua2,Fz2,'k',ua3,Fz3,'k',ua4,Fz4,'k',ua5,Fz5,'k');
title('驱动力-行驶阻力平衡图');
xlabel('ua(km/s)');
ylabel('Ft(N)');
legend('Ft1','Ft2','Ft3','Ft4','Ft5','Ff+Fw')
%求最高车速。
[x,y]=ginput
(1);
disp(‘汽车最高车速=');disp(x);disp('km/h');
(2)
%汽车最大爬坡度
clear
clc
%汽车相关参数。
m=3880;
g=9.8;
nmin=600;
nmax=4000;
G=m*g;
ig=[5.562.7691.6441.000.793];
y=0.85;r=0.367;f=0.013;CdA=2.77;i0=5.83;
L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;
n=600:
10:
4000;
Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4;
Ft1=Tq*ig
(1)*i0*y/r;%一档时爬坡能力最强。
ua1=0.377*r*n/ig
(1)/i0;
Ff=G*f;%滚动阻力。
Fw1=CdA*ua1.^2/21.15;%空气阻力。
Fz1=Ff+Fw1;
Fi1=Ft1-Fz1;
Fmax=max(Fi1/G);
imax=100*tan(asin(Fmax));
disp('汽车最大爬坡度=');
disp(imax),disp('%');
(3)
%求汽车加速度倒数曲线和最大爬坡度显得附着率。
clear
clc
m=3880;%汽车相关参数。
g=9.8;
nmin=600;
nmax=4000;
G=m*g;
ig=[5.562.7691.6441.000.793];
y=0.85;r=0.367;f=0.013;CdA=2.77;i0=5.83;
L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;
n=600:
10:
4000;%发动机转速范围。
Tq=-19.313+295.27*(n/1000)-165.44*(n/1000).^2+40.874*(n/1000).^3-3.8445*(n/1000).^4;
Ft1=Tq*ig
(1)*i0*y/r;%各档位下的驱动力。
Ft2=Tq*ig
(2)*i0*y/r;
Ft3=Tq*ig(3)*i0*y/r;
Ft4=Tq*ig(4)*i0*y/r;
Ft5=Tq*ig(5)*i0*y/r;
ua1=0.377*r*n/ig
(1)/i0;%各档位下的车速。
ua2=0.377*r*n/ig
(2)/i0;
ua3=0.377*r*n/ig(3)/i0;
ua4=0.377*r*n/ig(4)/i0;
ua5=0.377*r*n/ig(5)/i0;
Fw1=CdA*ua1.^2/21.15;%空气阻力。
Fw2=CdA*ua2.^2/21.15;
Fw3=CdA*ua3.^2/21.15;
Fw4=CdA*ua4.^2/21.15;
Fw5=CdA*ua5.^2/21.15;
Ff=G*f;%滚动阻力。
q1=1+(Iw1+Iw2)/(m*r^2)+(If*ig
(1)^2*i0^2*y)/(m*r^2);%求各档位下的汽车旋转质量换算系数。
q2=1+(Iw1+Iw2)/(m*r^2)+(If*ig
(2)^2*i0^2*y)/(m*r^2);
q3=1+(Iw1+Iw2)/(m*r^2)+(If*ig(3)^2*i0^2*y)/(m*r^2);
q4=1+(Iw1+Iw2)/(m*r^2)+(If*ig(4)^2*i0^2*y)/(m*r^2);
q5=1+(Iw1+Iw2)/(m*r^2)+(If*ig(5)^2*i0^2*y)/(m*r^2);
a1=(Ft1-Ff-Fw1)/(q1*m);%求出汽车加速度。
a2=(Ft2-Ff-Fw2)/(q2*m);
a3=(Ft3-Ff-Fw3)/(q3*m);
a4=(Ft4-Ff-Fw4)/(q4*m);
a5=(Ft5-Ff-Fw5)/(q5*m);
ad1=1./a1;;%求加速度倒数。
ad2=1./a2;
ad3=1./a3;
ad4=1./a4;
ad5=1./a5;
plot(ua1,ad1,ua2,ad2,ua3,ad3,ua4,ad4,ua5,ad5);%绘制加速度倒数曲线。
axis([0100010]);
title('汽车的加速度倒数曲线');
xlabel('ua(km/h)');
ylabel('1/a');
legend('ad1','ad2','ad3','ad4','ad5')
%求最大爬坡度时的附着率。
Fz=Ft1-Ff-Fw1;
aa=asin(max(Fz)/G);%最大爬坡角度。
C=tan(aa)/(a/L+hg*tan(aa)/L);%附着率。
disp('假设后轮驱动,最大爬坡度相应的附着率=);
disp(C);
(4)%求汽车2档原地起步换挡加速行驶至70km/h的加速时间
clear
nT=0.85;
r=0.367;
f=0.013;CDA=2.77;
i0=5.83;If=0.218;
Iw1=1.798;Iw2=3.598;
L=3.2;a=1.947;hg=0.9;
m=3880;g=9.8;
ig=[5.562.7691.6441.000.793];
G=m*g;
nmin=600;nmax=4000;
u1=0.377*r*nmin./ig/i0;
u2=0.377*r*nmax./ig/i0;
deta=0*ig;
fori=1:
5
deta(i)=1+(Iw1+Iw2)/(m*r^2)+(If*(ig(i))^2*i0^2*nT)/(m*r^2);
end
ua=6:
0.01:
99;N=length(ua);n=0;Tq=0;Ft=0;inv_a=0*ua;delta=0*ua;
Ff=G*f;
Fw=CDA*ua.^2/21.15;
fori=1:
N
k=i;
ifua(i)<=u2
(2)
n=ua(i)*(ig
(2)*i0/r)/0.377;
Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/1000)^4;
Ft=Tq*ig
(2)*i0*nT/r;
inv_a(i)=(deta
(2)*m)/(Ft-Ff-Fw(i));
delta(i)=0.01*inv_a(i)/3.6;
elseifua(i)<=u2(3)
n=ua(i)*(ig(3)*i0/r)/0.377;
Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/1000)^4;
Ft=Tq*ig(3)*i0*nT/r;
inv_a(i)=(deta(3)*m)/(Ft-Ff-Fw(i));
delta(i)=0.01*inv_a(i)/3.6;
elseifua(i)<=u2(4)
n=ua(i)*(ig(4)*i0/r)/0.377;
Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/1000)^4;
Ft=Tq*ig(4)*i0*nT/r;
inv_a(i)=(deta(4)*m)/(Ft-Ff-Fw(i));
delta(i)=0.01*inv_a(i)/3.6;
else
n=ua(i)*(ig(5)*i0/r)/0.377;
Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)^2+40.874*(n/1000)^3-3.8445*(n/1000)^4;
Ft=Tq*ig(5)*i0*nT/r;
inv_a(i)=(deta(5)*m)/(Ft-Ff-Fw(i));
delta(i)=0.01*inv_a(i)/3.6;
end
a=delta(1:
k);
t(i)=sum(a);
end
plot(t,ua);
axis([0800100]);
title('汽车2档原地起步换挡加速时间曲线');
xlabel('时间t(s)');
ylabel('速度ua(km/h)');
2.7matlab程序:
(1)
%绘制汽车功率平衡图。
clear
%汽车参数。
ig=[5.562.7691.6441.000.793];
y=0.85;r=0.367;f=0.013;CdA=2.77;i0=5.83;
L=3.2;a=1.947;hg=0.9;If=0.218;Iw1=1.798;Iw2=3.598;m=3880;g=9.8;
G=m*g;
n=600:
10:
4000;
Tq=-19.313+295.27*(n/1000)-165.44*(n/1000)