Fourbar Linkage Coupler Path

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Charitha Heshan 2018-9-19

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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/419878-fourbar-linkage-coupler-path

评论： Kerith Lumiares 2022-8-25

hey guys im writing to a code to demonstrate NON Grashof four bar triple rocker to plot the coupler curve of point P with respect to the global reference frame XY & the transmission angles vs input angles.Im not very good at matlab so if you could point out what i should understand that will be very helpful.

if true
%code
% // Note and symbols
% // R2 Input link // R1 ground link // R3 coupler link // R4 rocker
% // P coupler point // beta the coupler angle(Degrees) 
% // RA,RB,RP,RPA position vector of the point A, B, P, point P refer to point A  
% // input data for 4 bar linkage %
fprintf('\n');
L1 = input('input ground = ');  
L2 = input('input link 2 = ');
L3 = input('input link 3 = ');
L4 = input('input link 4 = ');
fprintf('\n');
 % // define point p position.
fprintf('\n');
PA = input('input link PA = ');
qpd = input('input point P (degree)= ');
fprintf('\n');
% // transfer 4 bar dimension
R1 = L1; R2 = L2; R3 = L3; R4 = L4;  %qpd = 56.0;
beta=qpd
%cta = 14;
alpha = cta
q2=arccos(((a.^2+d.^2-b.^2-c.^2)/(2*a*d))- (b*c)/(a*d)))
%Define K
K1 = d/a
K4 = d/b
K5 = (c^2 - d^2 - a^2 - b^2) / (2*a*b)
%
D(q2) = cos(q2) - K1 + K4*cos(q2) + K5
E(q2) = -2*sin(q2)
F(q2) = K1 + (K4-1)*cos(q2) + K5
%
q31(q2) = 2*atand (( -E + sqrt(E^2 -4*D*F))/2*D)
q32(q2) = 2*atand (( -E - sqrt(E^2 -4*D*F))/2*D)
    % // coupler position (P)
    RA(q2) = a*(cos(q2) + j*sin(q2));
    RPA(q2) = p*(cos(q3+beta) + j*sin(q3+beta));
    RP = RA + RPA;
    RPx(q2) = a*cos(q2)+p*cos(q3(q2)+beta);   % position x of link P
    RPy(q2) = a*sin(q2)+p*sin(q3(q2)+beta);   % position y of link P
% Transform to the Global Frame
Xp(q2) = RPx(q2)*cos(alpha)-RPy(q2)*sin(alpha)
Yp(q2) = RPx(q2)*sin(alpha)+RPy(q2)*cos(alpha)
 // plot path A, B and P
subplot(3,2,1);
plot(Ax,Ay, Bx,By, Px,Py)  % path for A,B and P
title('linkage path motion')
legend('point A','point B','point P')
ylabel('y-axis')
xlabel('x-axis')
axis([xmin*1.5 xmax*1.5 ymin ymax])
daspect([1 1 1]) % fix plot ratio 1:1
set(legend,'color','none');
grid on
end