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Math Forum / Math Software / MATLAB / July 2008Major problem with program
I am working on a class project that I am having a hell of a time with. I posted a link to a .pdf file that is the actual program. So far, I have created an .m file with the variables defined and it works fine but now I am having problems with the eigen functions and normalizing vectors. Any help would be greatly appreciated as I am in a time crunch. I am not very good with MATLAB so please be gentle. Thanks! http://www.ftpp.net/MATLABProject.pdf Thanks in advance for everyone's help! Josh <jcyork01@louisville.edu> wrote in message <909073.1196635547944.JavaMail.jakarta@nitrogen.mathforum.org>... > I am working on a class project that I am having a hell of a time with. I posted a link to a .pdf file that is the actual program. So far, I have created an .m file with the variables defined and it works fine but now I am having problems with the eigen functions and normalizing vectors. Any help would be greatly appreciated as I am in a time crunch. I am not very good with MATLAB so please be gentle. Thanks! > http://www.ftpp.net/MATLABProject.pdf > > Thanks in advance for everyone's help! Post your work so far, you will be more likely to get a response if people see you are really trying. Definitions.m %Weight Initialization file % Variable definitions % Mc: Mass of vehicle(car) % Jc: Moment of inertia value for vehicle (car) % Mb: Mass of suspension components % Jb: Moment of inertia for suspension components % Mw: Mass of wheel % K1 - Spring Rate 1 % K2 - Spring Rate 2 % Lw - Wheelbase length - left to right % Lb - Wheelbase length - front to rear % << Variable Definitions - Values Lb=2.57; %meters Lw = 1.52; %meters K1 = 60; %Spring Rate: kg*m^2 K2 = 50; %Spring Rate: kg*m^2 Mc=1500; %Mass of vehicle Jc=1114.4; %Moment of Inertia - Vehicle Mb=25; %Mass of Suspension Pieces Jb=.3; %Moment of Inertia - Suspension Mw=20.0; %Mass of Wheel % Mv = [Mc Jc Mb Jb Mb Jb Mw Mw Mw Mw] in a diagonal fashion % Mv[1,10] Mv = [Mc 0 0 0 0 0 0 0 0 0; 0 Jc 0 0 0 0 0 0 0 0; 0 0 Mb 0 0 0 0 0 0 0; 0 0 0 Jb 0 0 0 0 0 0; 0 0 0 0 Mb 0 0 0 0 0; 0 0 0 0 0 Jb 0 0 0 0; 0 0 0 0 0 0 Mw 0 0 0; 0 0 0 0 0 0 0 Mw 0 0; 0 0 0 0 0 0 0 0 Mw 0; 0 0 0 0 0 0 0 0 0 Mw]; Kv = [(2*K2) 0 -K2 0 -K2 0 0 0 0 0; 0 (2*K2*Lb^2) (-K2*Lb) 0 (K2*Lb) 0 0 0 0 0; -K2 (-K2*Lb) (K2+2*K1) 0 0 0 -K1 -K1 0 0; 0 0 0 (2*K1*Lw^2) 0 0 (-K1*Lw) (K1*Lw) 0 0; -K2 (K2*Lb) 0 0 (K2+2*K1) 0 0 0 -K1 -K1; 0 0 0 0 0 (2*K1*Lw^2) 0 0 (-K1*Lw) (K1*Lw); 0 0 -K1 (-K1*Lw) 0 0 K1 0 0 0; 0 0 -K1 (K1*Lw) 0 0 0 K1 0 0; 0 0 0 0 -K1 (-K1*Lw) 0 0 K1 0; 0 0 0 0 -K1 (K1*Lw) 0 0 0 K1]; % To get Eigen values and vectors: [K, M]=eig(Kv, Mv) % Note: Eigenvalue is M, Eigenvector is M [K, M]=eig(Kv, -Mv) % fn = natural frequency fn = M/(2*pi) % Eliminate Zeroes sparse(fn) Josh <jcyork01@louisville.edu> wrote in message <18956547.1196639536763.JavaMail.jakarta@nitrogen.mathforum.org>... > Definitions.m > [quoted text clipped - 25 lines] > % Mv[1,10] > Mv = [Mc 0 0 0 0 0 0 0 0 0; 0 Jc 0 0 0 0 0 0 0 0; 0 0 Mb 0 0 0 0 0 0 0; 0 0 0 Jb 0 0 0 0 0 0; 0 0 0 0 Mb 0 0 0 0 0; 0 0 0 0 0 Jb 0 0 0 0; 0 0 0 0 0 0 Mw 0 0 0; 0 0 0 0 0 0 0 Mw 0 0; 0 0 0 0 0 0 0 0 Mw 0; 0 0 0 0 0 0 0 0 0 Mw]; > Kv = [(2*K2) 0 -K2 0 -K2 0 0 0 0 0; 0 (2*K2*Lb^2) (-K2*Lb) 0 (K2*Lb) 0 0 0 0 0; -K2 (-K2*Lb) (K2+2*K1) 0 0 0 -K1 -K1 0 0; 0 0 0 (2*K1*Lw^2) 0 0 (- K1*Lw) (K1*Lw) 0 0; -K2 (K2*Lb) 0 0 (K2+2*K1) 0 0 0 -K1 -K1; 0 0 0 0 0 (2*K1*Lw^2) 0 0 (-K1*Lw) (K1*Lw); 0 0 -K1 (-K1*Lw) 0 0 K1 0 0 0; 0 0 -K1 (K1*Lw) 0 0 0 K1 0 0; 0 0 0 0 -K1 (-K1*Lw) 0 0 K1 0; 0 0 0 0 -K1 (K1*Lw) 0 0 0 K1]; > % To get Eigen values and vectors: [K, M]=eig(Kv, Mv) > % Note: Eigenvalue is M, Eigenvector is M [quoted text clipped - 5 lines] > % Eliminate Zeroes > sparse(fn) Um, sparse does not actually eliminate any zeros. This is not its purpose, nor does it really have that effect, even if unintentional. So what is your purpose here? My guess is that you wish to extract only the diagonal elements of the diagonal matrix that eig returns. Use diag for this purpose. John Great! I used the diag function and it worked great. Thanks for that. Still in need of more help! Josh <jcyork01@louisville.edu> wrote in message <21914604.1196644917957.JavaMail.jakarta@nitrogen.mathforum.org>... > Great! I used the diag function and it worked great. Thanks for that. Still in need of more help! Ok. So you need more help. On what? Give us a hint, since at least my own crystal ball is always hazy. What did you try? What is wrong? John check a book by Ogota and the matlab help files for tutorials. they helped me. |
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