Scissor

%SCISSOR.M – simulation of a scissor elevating platform

AO = 1.7;       % m
AE = 1.85;      % m
BC = 3.4;       % m
W  = 20000;     % N
d  = 0.5;       % m
V  = 0.05;      % m/s
a  = 0.9;       % initial cylinder length
% _____________
time = [ ];     % initiate array of time values
F  = [ ];       % initiate array of F values
%  begin loop
for t = 0: 0.25: 10      % s
time = [ time t ];  % update array of time values
EO = a + V*t;       % m
% calculate angles in radians
AEO = acos((AE*AE + EO*EO – AO*AO)/(2*AE*EO));
ABC = acos((AE*AE + AO*AO – EO*EO)/(2*AE*AO));
% calculate matrix of coefficients
A = [ cos(ABC) 0 -cos(AEO)
sin(ABC) 1  sin(AEO)
0 BC*cos(ABC)/2 0 ];
% calculate inhomogeneous vector
B = [ 0; 1; -d ]*W;
% solve system
X= A\B;
F = [ F X(3) ];     % update array of force values
end
plot(time, F)
grid
xlabel(‘time, t, s’)
ylabel(‘cylinder force, F, N’)