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Matlab Kinematics question

  1. Dec 11, 2004 #1
    I know this is a programming language question, but no one seems to answer in that Forum. I'm running a program in Matlab and I'm running two loops One for the velocities in the x,y,z components and another for the magnus force (spin) vx,vy,vz. I'm holding all constant except vy and vz which I switch one at a time while holding the other constant. I need to find the spin in the vy then the vz that makes it within my constraints I have in place in my program. I try running now but it is just non-stop numbers that come out any help will be great. Thank you

    clear;
    Cd = .5;
    Cs = .5;
    p = 1.2; %Air density
    r = .11303; %radius
    m = .4536; %mass


    x(1) = 0; %initial position
    y(1) = 0;
    z(1) = 0;

    wx = 0; %initial angular velocity for x

    wy = 0;

    vx(1) = 14.95; %intial velocity for x
    vy(1) = 14.5;
    vz(1) = 7.9;
    k = -300;
    g = 9.81; %gravity
    dt = .001;
    t = 20;
    n = t/dt;

    for j = 1:n
    wz = j;
    for i = 1:n

    u = sqrt((vx(i))^2+(vy(i))^2+(vz(i))^2); %v for all components

    ax = (-((Cd*p*pi*r^2)*u*vx(i))/(2*m) - ((Cs*p*pi*r^3*(vz(i)*wy-wz*vy(i)))/(2*m)));
    ay = (-((Cd*p*pi*r^2)*u*vy(i))/(2*m) - ((Cs*p*pi*r^3*(wz*vx(i)))/(2*m)));
    az = ((-g)-((Cd*p*pi*r^2)*u*vz(i))/(2*m) + ((Cs*p*pi*r^3*(-wy*vx(i)))/(2*m)));

    Fx = ax*m; %Force for x-component
    Fy = ay*m;
    Fz = az*m;

    vx(i+1) = vx(i) + ((Fx/m)*dt); %Final velocity for x-component
    vy(i+1) = vy(i) + ((Fy/m)*dt);
    vz(i+1) = vz(i) + ((Fz/m)*dt);

    x(i+1) = x(i) + vx(i+1)*dt;
    y(i+1) = y(i) + vy(i+1)*dt;
    z(i+1) = z(i) + vz(i+1)*dt;

    if(x(i+1)>(11.531+ .1524))

    break
    end

    if((y(i+1)>10.9564)&(y(i+1)<11.531))&((z(i+1)>1.8288)&(z(i+1)<2.3254))&((x(i+1)>11.531)&(x(i+1)<(11.531+.1524)))
    fprintf('q')
    break

    end

    end
    fprintf('number %g',wz);
    end

    plot3(x,y,z)
    grid on
     
  2. jcsd
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