I need help developing a 3DOF mechanism that has 6 joints and completes a 360 degree rotation. The mechanisim is a R_R_R_R_T_R.

Here is my mechanism and my data. I am having real touble with a function in my code. "solD = solve(eqD1, eqD2, 'xDsol, yDsol');"

It keeps giving me an error.

Help would be much apprecitaed!

The code I am working with can be found below.

Notice I included my data.

I also had to figure out how to represent 320 degrees as phi. I think it can be pi/10? I am not sure. Maybe this can help better. I am essentially using this code format to edit it for my project.

Some of the code I am sure does not make sense, since I am still working on it and trying to figure out how to manipulate things to reprsent my problem. I have already solved this via the classical method. I am just trying to put it in matlab for the first time.

clear all; clc; close all
OA = 0.0400;
AB = 0.100;		% m 	
BC = 0.070;		% m 	
OC = 0.120;		% m		
CE = 0.060;		% m		
DE = 0.065;		% m
La = 0.30 ;		% m
Lb = 0.40 ;		% m
Lc = OC   ;		% m
phi = pi/10; 	% rad
omega = pi; 	% rad/s
alpha = 0.;	    % rad/s^2

% position of joint A: 
xA = 0; yA = 0;

% at the initial moment phi=0 => increment = 0
increment = 0 ; 

% the step has to be small for this method
step=pi/18; 
for phi=pi/10:step:pi/10+2*pi,
fprintf('phi =  %g deegres \n\n', phi*360/pi)

% call function driver
jointB = driver(xA,yA,AB,phi,omega,alpha);

% position of joint B 
xB = jointB(1);
yB = jointB(2);
rB = [xB yB 0];
fprintf('rB = [%6.3g, %6.3g, %g] (m)\n', rB)

xD = La; yD = Lb;
rD = [xD yD 0];

% position of joint C 
% call function pRRR
posC = pRRR(xB,yB,xD,yD,BC,CD);

xC1 = posC(1); yC1 = posC(2);
xC2 = posC(3); yC2 = posC(4);

if increment == 0
  if yC1 > yB xC = xC1; yC = yC1;  
  else xC = xC2; yC = yC2; end
else
  dist1 = Dist(xC1,yC1,xCold,yCold);
  dist2 = Dist(xC2,yC2,xCold,yCold);
  if dist1<dist2 xC=xC1; yC=yC1; 
  else xC=xC2; yC=yC2; end
end
xCold=xC;
yCold=yC;
increment=increment+1;

rC = [xC yC 0]; % position vector of C 
fprintf('rC = [%6.3g, %6.3g, %g] (m)\n', rC)
% angle of the link 2 with the horizontal
phi2 = atan((yB-yC)/(xB-xC));
% angle of the link 3 with the horizontal
phi3 = atan((yC-yD)/(xC-xD))+pi ;

xE = xD+(CD+CE)*cos(phi3);
yE = yD+(CD+CE)*sin(phi3);


% % call function p3P (D, C, E on line)
% posE = p3P(xD,yD,xC,yC,CD+CE);
% xE1 = posE(1); yE1 = posE(2); 
% xE2 = posE(3); yE2 = posE(3); 
% 
% fprintf('xE1 = %6.3g \n', xE1)
% fprintf('yE1 = %6.3g \n', yE1)
% fprintf('xE2 = %6.3g \n', xE2)
% fprintf('yE2 = %6.3g \n', yE2)
% 
% if yE1 > yC xE = xE1; yE = yE1;  
% else xE = xE2; yE = yE2; end


rE = [xE yE 0]; % position vector of E 
fprintf('rE = [%6.3g, %6.3g, %g] (m)\n', rE)

xF = - Lc;
phi5 = pi/2;

% position of joint F
% call function pRRT
posF = pRRT(xE,yE,-Lc,0,EF,phi5);
yF1 = posF(2); yF2 = posF(4); 

if yF1 < yE yF = yF1; else yF = yF2; end
rF = [xF yF 0]; % position vector of F 
fprintf('rF = [%6.3g, %6.3g, %g] (m)\n', rF)


% angle of the link 4 with the horizontal
phi4 = atan((yE-yF)/(xE-xF));

fprintf('phi2 = %g (degrees) \n', phi2*360/pi);
fprintf('phi3 = %g (degrees) \n', phi3*360/pi);
fprintf('phi4 = %g (degrees) \n\n', phi4*360/pi);

x_C2(increment)=(xB+xC)/2;
y_C2(increment)=(yB+yC)/2;

% graphic of the mechanism
axis manual
axis equal
hold on
grid on
% axis([-0.7 0.7 -0.7 0.7])
axis([-0.4 0.4 -0.2 0.7])
xlabel('x (m)'),ylabel('y (m)')

pM=plot(...
   [xA,xB],[yA,yB],'r-o',...
   [xB,xC],[yB,yC],'b-o',...   
   [xD,xE],[yD,yE],'k-o',...   
   [xE,xF],[yE,yF],'r-o');
plot(x_C2, y_C2, 'k.','Color', 'red')
pause(1);
delete(pM);

end

text(xA,yA,'  A'), text(xB,yB,'  B')
text(xC,yC,'  C'), text(xD,yD,'  D')
text(xE,yE,'  E'), text(xF,yF,'  F')
grid on

plot(...
   [xA,xB],[yA,yB],'r-o',...
   [xB,xC],[yB,yC],'b-o',...   
   [xD,xE],[yD,yE],'k-o',...   
   [xE,xF],[yE,yF],'r-o')

title('Path described by C_2')

% end of program

[John D'Errico]

Since you don't show the function that keeps giving you an error, nor do you even tell anyone what the error is, how do you expect help?

So far, the only answer is for someone to either do your assignment for you, to to tell you to write better code that does not cause errors.

If you want help, then make it possible for you to get help. Make it easy to give you help. Show us what you did do. Don't just say you did something and it did not work. When you show what you did, then all we need to do is show you how to fix it.

[University Student]

I updated my post. Thanks

[University Student]

Actually, I am having errors with using the joint function aswell.