Unable to perform assignment because the indices on the left side are not compatible with the size of the right side.
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Xavier Croes
el 12 de Mzo. de 2020
Comentada: Star Strider
el 12 de Mzo. de 2020
In the first part the codes work perfectly and it calculates all the forces Fp. In the second line the loop won't work, but I do the exact same thing.
Thanks for the help!
close all
clear all
%% Piston kracht
F1=100 %[N]
hoekF=90
slopearm=[0:1:90]
alpha=90-hoekF+slopearm
r=25
x=20
hoeksup=asind((3*sind(135-slopearm))/(square((x^2)+(3^2)-2*x*3*cosd(135-slopearm))))
beta=90-hoeksup
syms Fp
eqn=F1*cosd(alpha)*r==Fp*cosd(beta)*x
for K = 1 : length(eqn)
d(K) = double(vpasolve(eqn(K), Fp))
end
plot(slopearm,d)
title('Krachtverloop in bovenste piston')
%% Scharnier krachten F2 en F3
syms F2
Xs=F1*sind(alpha)+d*sind(beta)-F2*sind(alpha)==0
Ys=F1*cosd(alpha)-d*cosd(beta)-F2*cosd(alpha)==0
for A = 1 : length(Xs)
k(A) = double(vpasolve(Xs(A), F2))
end
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Respuesta aceptada
Star Strider
el 12 de Mzo. de 2020
The problem is that the first element of ‘Xs’:
4501354550746679/8796093022208 == 0
is not a function of ‘F2’, so it returns an empty element.
Beginning the loop at 2 (and preallocating ‘k’), iavoids that problem:
k = zeros(size(Xs));
for A = 2 : length(Xs)
k(A) = double(vpasolve(Xs(A), F2));
end
The first element of ‘k’ is now 0.
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Más respuestas (1)
Walter Roberson
el 12 de Mzo. de 2020
alpha starts out 0. sind(0) is 0. Multiply by F2 and you get 0. Therefore the equation becomes independent of the variable you are trying to solve for and so vpasolve cannot find a solution and returns empty.
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