I have prepared MATLAB code using ODE45 for calling function. Its giving error as "input argument 'z' is undefined. zp(1) = z(2); "

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ANIKET KADAM
ANIKET KADAM 2016-4-13
评论： PRASHANT JAIN 2020-10-23
%apple solver code
x0=1e-6; %initial position
xp0=0; %initial velocity
y0=1e-6; %initial position
yp0=0; %initial velocity
tspan=[0 1e-4 0.296];
z0 = [1e-6; 0; 1e-6; 0];
[t,z] = ode45('apple',tspan,z0);
plot(t,z(:,1));
grid on
%%function for solver
function zp = apple(t,z)
m = 20; %%mass of shaft in Newton
k = 170e6; %%stiffness of bearing (k^inner = k^outer)
Pd = 20e-6; %%diametral clearance of ball bearing
tp = 0.296; %%time period
s=13; %%Number of balls
wc = 21.26; %%speed of bearing cage in rad/sec for 500rpm
si = 0; %%angular location of defect on race of bearing
phi0 = 0; %%initial position of ith ball
for t =0 : 1e-2: tp %time increment
for i = 1:1:s; %%ball increment
phi(i) = 2*pi*i/s + wc * t + phi0; %%calculation of ith ball angle
c = Pd/2 * (1 - cos(phi(i))); %%calculation of radial clearance
if phi(i) == si %%condition for ball in region of defect
b = 1;
delta = 1.0586e-2; %%additional deflection of ball when it passes through defect
else
b = 0; %%non-defective region
end
%solving Equation of motion for specified time period using
%Runge Kutta method (ode45)
%converting higher order equations into first order
zp=zeros(4,1);
zp(1)=z(2);
zp(2)=(k*cos(phi(i))/m) * ((z(1)*cos(phi(i)) + z(3)*sin(phi(i)) - b*delta - c)^(3/2) - (z(1)*cos(phi(i)) + z(3)*sin(phi(i)) - b*delta)^(3/2)); %%((a - c)^(3/2) - (a)^(3/2)
zp(3)=z(4);
zp(4)=(k*sin(phi(i))/m) * ((z(1)*cos(phi(i)) + z(3)*sin(phi(i)) - b*delta - c)^(3/2) - (z(1)*cos(phi(i)) + z(3)*sin(phi(i)) - b*delta)^(3/2));
end
end
end

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回答（1 个）

Walter Roberson
Walter Roberson 2016-4-13
Try changing to
[t,z] = ode45(@apple,tspan,z0);
and remember that you need to run apple_solver rather than apple
  2 个评论
Walter Roberson
Walter Roberson 2016-4-13
Your code only defines delta when phi(i) == si .
The filename you used when you attached was apple[1].m . The filename would have to be apple.m for MATLAB to be able to find the code. You might find you already have a different apple.m that is being invoked.

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