Week 2- 2R Robotic Arm Challenge

Aim : A program to simulate the Forward kinematics of a 2R Robotic arm

Explanation :

In shown figure there is two links Link1 and Link2 with two rotational joints and Manipulator

Link1 is making an angle θ1 with respect of x_axis, Link2 is making an angle θ2 with respect of y_axis.

Here, the starting point is fixed to base and ending point connected to link2

The coordinate of starting point will be (0,0)

Drawing second link separately

That end point of link1 is starting point of link2,the coordinate will be (x1,y1)

the coordinate of (x2,y2) will be for end manipulator

Equations :

x1=l1*cosd(theta1)

y1=l1*sind(theta1)

x2=x1+l2*cosd(theta2)

y2=y2+l2*sind(theta2)

[x0 y0],[x1 y1],[x2 y2] using

these coordinates we can write a program and make an animation.

Solution : In MATLAB before starting program better use these commands to erase previous calculation

clear all - this command will clear all data stored in workspace

close all - this command will closes all figures and plots

clc - this command clears the command window

first we are using Inputs

l1=1

l2= 0.5

θ1=45

θ2=30

Then ,

x0=0

y0=0

code :

% Forward kinematics of a 2D Robotic arm manipulator

clear all
close all
clc
% Inputs
l1=1;
l2=0.5;

theta1=45;
theta2=30;

% coordinates
x0=0;
y0=0;

x1=l1*cosd(theta1);
y1=l1*sind(theta1);

x2=x1+l2*cosd(theta2);
y2=y1+l2*sind(theta2);

% plotting
line([x0,x1],[y0,y1],'linewidth',3,'color','b')
line([x1,x2],[y1,y2],'linewidth',3,'color','r')

% Animation of Forward kinematics 2R robotic arm
clear all
close all
clc


% Inputs
l1 = 1;
l2 = 0.5;
theta1 = linspace(0,90,10);
theta2 = linspace(0,90,10);
ct = 1;
for i = 1:length(theta1)
   THETA1 = theta1(i);
   for j = 1: length(theta2)
   THETA2 = theta2(j);
   x0=0;
   y0=0;

x1=l1*cosd(THETA1);
y1=l1*sind(THETA1);

x2=x1+l2*cosd(THETA2);
y2=y1+l2*sind(THETA2);

% plotting
plot([x0,x1],[y0,y1],[x1,x2],[y1,y2],'lineWidth',3)
axis([-0.1 1.5 0 1.5])
pause(0.03)
M(ct) = getframe(gcf);
ct = ct+1;

   end
 
end

movie(M)
videofile = VideoWriter('forward_kinematics.avi','Uncompressed AVI');
open(videofile)
writeVideo(videofile,M)
close(videofile)

Output Result :

Animation link :

https://youtu.be/NzNmAWDkMdE

https://drive.google.com/file/d/1wQdKpT9V5DnrM8cMrmRWKrBVHhge4Ycj/view?usp=sharing

Errors occured during program :

showed error due to capital letter of Movie,solved after writing small lettered movie

while programming got error due to writing (Uncompressed.Avi) wrong profile name

solved after writing (Uncompressed AVI) profile name.

Got error wrote wrong name (Videofile)

Got solved after writing (videofile)

Conclusion : The program for 2R robotic arm forward kinematics was coded and the position fo manipulator was simulated in MATLAB plot as a video.

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