汽车万有特性曲线绘制

程序如下：

%%%%%%%%%%´从表格中读取数据%%%%%%%%%%%

n=xlsread('d:\Program

Files\MATLAB\R2010b\bin\wanyoutexing1\wanyoutexing.xls','sheet1','a4: a83');

Ttq=xlsread('d:\Program

Files\MATLAB\R2010b\bin\wanyoutexing1\wanyoutexing.xls','sheet1','b4: b83');

be=xlsread('d:\Program

Files\MATLAB\R2010b\bin\wanyoutexing1\wanyoutexing.xls','sheet1','c4: c83');

Z=[ones(size(n)),n,Ttq,n.^2,n.*Ttq,Ttq.^2]; %%%%%%%%%%%%%%%%求出回归参数%%%%%%%%%%%%%%%%%

A=Z\be;

n1=1400:2:2800;

Ttq1=20:0.1:426;

[Ttq1,n1]=meshgrid(Ttq1,n1);

%%%%%%%%%%%%%%建立拟合后的be矩阵%%%%%%%%%%%%%%%

be1=A(1)+A(2)*n1+A(3)*Ttq1+A(4)*n1.^2+A(5)*n1.*Ttq1+A(6)*Ttq1.^2; %%%%%%%%%%%%%绘制be-pme-n%%%%%%%%%%%%%

mesh(n1,Ttq1,be1)

title('be-Ttq-n 三维曲面')

xlabel('n / (r/min)')

ylabel('Ttq / N.m')

zlabel('be / (g/(kW.h))')

figure

%%%%%%%%%%%取be-Ttq-三维曲面的等高线%%%%%%%%%%%%

cs=contour(n1,Ttq1,be1,35);

clabel(cs);

title('万有特性曲线')

xlabel('n/(r/min)')

ylabel('Ttq/N.m')

%%%%%%%%%%%%%%%%拟合外特性曲线%%%%%%%%%%%%%%%%%

n0=[1400 1600 1800 2000 2200 2400 2600 2800];

Ttq_max0=[399.8 409.1 408.3 425.6 420.7 404.6 378 315.6]; Ttq_max0_para=polyfit(n0,Ttq_max0,2);

Ttq_max=polyval(Ttq_max0_para,n1);

hold on

%%%%%%%在万有特性的曲线上绘制拟合后的外特性曲线%%%%%%%% %%%%%%%%%%%%作为万有特性曲线的边界线%%%%%%%%%%%%%

plot(n1,Ttq_max,'b+')

结果如下图