How to perform an animation of a 5bar parallel link (this is a 2D plot of a 5 bar link) in matlab?

Hi there,

I am new to Matlab, but have been trying to work a code out such that it produces a 5 bar parallel link as seen in the image below. I am able to plot it based on values of theta1 and theta5. So by changing these 2 theta values, I get a different plot as seen in the 2nd image.

However, I am tryong to animate the plot such that the whole figure moves over a series of theta values. I have been trying it out, but I am unable to get the code working. May I know if anayone is able to help me out with the code for animation?

Thank you.

% Five bar link centre of mass calculation
%Sanjeev Code% 
%%Input the values of the length of the links%% 
l0 = input ('What is the value of l0?');
l1 = input ('What is the value of l1?'); 
l2 = input ('What is the value of l2?');
l3 = input ('What is the value of l3?');
l4 = input ('What is the value of l4?'); % link lengths

% Base joint positions
P5 = [0;0]; 
P1 = [l0;0]; 

%%Input the values of theta%% 
Theta1 = 70;
Theta5 = 140;

%%Let theta be q%% 
q1 = Theta1;
q5 = Theta5;

% Positions of P2 and P4 via trignometry
P4 = P5+l4*[cosd(q5);sind(q5)];
P2 = P1+l1*[cosd(q1);sind(q1)];

d24 = norm(P4-P2); % Distance between P2 and P4

% Bilateration method to find P3
A_243 = -sqrt((d24^2+l2^2+l3^2)^2-2*(d24^4+l2^4+l3^4))/4; % Signed area of triangle formed by P2,P4, and P3
Z_243 = (1/(2*d24^2))*[(d24^2+l2^2-l3^2), -4*A_243; 4*A_243, (d24^2+l2^2-l3^2)]; % Bilateration matrix for this triangle

p24 = P4-P2; 
p23 = Z_243*p24;
P3 = P2 + p23;

% Centre of mass calculations
%%Input the values of s of the links%% 
s1 = 0.5; s2 = 0.5; s3 = 0.5; s4 = 0.5; 

u12 = (P2-P1)/norm(P2-P1); 
u23 = (P3-P2)/norm(P3-P2); 
u34 = (P4-P3)/norm(P4-P3);
u45 = (P5-P4)/norm(P5-P4); % Unit vectors of links

% mass centres for each link
M1 = P1 + s1*u12; 
M2 = P2 + s2*u23; 
M3 = P3 + s3*u34;
M4 = P4 + s4*u45; 

%m(1,2,3,4) is the masses of the moving links% 
m1 = input ('What is the value of m1 (kg)?'); 
m2 = input ('What is the value of m2 (kg)?');
m3 = input ('What is the value of m3 (kg)?');
m4 = input ('What is the value of m4 (kg)?'); 
M_tot = m1 + m2 + m3 + m4; % Total mass of linkage

% Centre of mass of linkage
com = (m1*M1+m2*M2+m3*M3+m4*M4)/M_tot; 

%Plot links% 
%Link P1 and P2 x,y cordinates%
axis([-2 2 -2 2])
x = [P1(1), P2(1)];
y = [P1(2), P2(2)];
plot(x,y, "k-s", "MarkerFaceColor","b","MarkerSize",12);
hold on 

% Link P2 and P3 x,y cordinates% 
axis([-2 2 -2 2])
x2 = [P2(1), P3(1)];
y2 = [P2(2), P3(2)];
plot(x2,y2, "k-s", "MarkerFaceColor","b","MarkerSize",12);
hold on 

% Link P3 and P4 x,y cordinates% 
axis([-2 2 -2 2])
x3 = [P3(1), P4(1)];
y3 = [P3(2), P4(2)];
plot(x3,y3, "k-s", "MarkerFaceColor","b","MarkerSize",12);
hold on 

%Link P4 and P5 x,y cordinates% 
axis([-2 2 -2 2])
x4 = [P4(1), P5(1)];
y4 = [P4(2), P5(2)];
plot(x4,y4, "k-s", "MarkerFaceColor","b","MarkerSize",12);
hold on 

%Plot the position of com% 
plot(com(1), com(2), 'r*');
hold on 

%Plot the centre of links% 
plot(M1(1), M1(2), "o", "MarkerFaceColor","black","MarkerSize",9); 
plot(M2(1), M2(2), "o", "MarkerFaceColor","black","MarkerSize",9); 
plot(M3(1), M3(2), "o", "MarkerFaceColor","black","MarkerSize",9); 
plot(M4(1), M4(2), "o", "MarkerFaceColor","black","MarkerSize",9); 

set(gca,'YDir', 'reverse')

[darova]

Can you show the angles you have

[Sanjeevan Nallathambbi]

Hi Darova,

Thanks for the message. The angle marked in your image is assigned as Theta1 which is 60degrees. Similarly, Theta5, is 120degrees as seen in the figure below. It is also stated in first part of the the code above, however in the code it is 70 and 140, which yields the second figure in my Question above. But nonetheless, Theta1 and Theta5 are represented in the attached figure below.

Code from the question:

%%Input the values of theta%% 
Theta1 = 70;
Theta5 = 140;
%%Let theta be q%% 
q1 = Theta1;
q5 = Theta5;

So the only way I can think of for the mechanism to be animated is by using the for loop and the variation of Theta1 and Theta5 values, but I am really unsure of how to do so as I am new to Matlab.

I really hope you can help me out with this and your help will be greatly appreciated. Thank you.

Answer 1

[darova]

I have similar code (attached)

some explanations:

Ask if something is needed

[Sanjeevan Nallathambbi]

could you let me know on how I can apply the for loop in my code to create the animation?

Thanks.

[darova]

Sorry, attached wrong file. See now