Challenge

Week 2- 2R Robotic Arm Challenge

AAshish Kumar Muduli27 Mar 2022

Program for the forward kinematics of a 2R Robotic Arm :-

clear all
close all
clc

%create a forward kinematics 2R robotic arm 

%inputs
l1=5;
l2=2;
l3=.5;
l4=.5;
l5=1;
l6=1;


theta1=linspace(30,150,10);
theta2=linspace(0,360,90);

ct=1;
for i=1:length(theta1)
    
for j=1:length(theta2)
        Theta2=theta2(j);
        c=360-Theta2;
        x0=0;
        y0=0;
        
        y1=l1*sind(theta1(i));
        x1=l1*cosd(theta1(i));
    
        x2=x1+l2*cosd(Theta2);
        y2=y1+l2*sind(Theta2);
        
        x3=x2+l3*sind(c);
        y3=y2+l3*cosd(c);
        
        x4=x2-l4*sind(c);
        y4=y2-l4*cosd(c);
        
        x5=x4+l5*cosd(c);
        y5=y4-l5*sind(c);
        
        x6=x3+l6*cosd(c);
        y6=y3-l6*sind(c);
         x8=-1;
         y8=0;
         
         x9=1;
         y9=0;
       
       plot([x0 x1],[y0 y1],[x1 x2],[y1 y2],[x2 x3],[y2 y3],[x2 x4],[y2 y4],[x4 x5],[y4 y5],[x3 x6],[y3 y6],[x8 x9],[y8 y9],'linewidth',3); 
        title('Robotic arm')
        xlabel('X-axis')
        ylabel('Y-axis')
         axis([-10 10 -10 10])
         pause(.03)
         M(ct)=getframe(gcf)
         ct=ct+1;
end
end
    
    movie(M)
    videofile=VideoWriter('robo.avi')
    open(videofile)
    writeVideo(videofile,M)
    close(videofile)

The above program is written for the forward kinematics of a 2R Rbotic arm.
Before writting the program we should know all the dimension of the link and coordinate location.
Here i mention the link name.
%inputs
l1=5;
l2=2;
l3=.5; These are the all link dimention ,first we have to mention it.
l4=.5;
l5=1;
l6=1;
theta1=linspace(30,150,10); - That means we have to divided theta1 in 10 equal parts from 30 deg. to 150 deg. that is 120 deg.
Note:- When we want to divided a variable into desirable equal parts ,then we used "linspace command" .
ct=1; - This is a counter command , It used when we want to represtent a figure window.
For i=1:length(theta1) -This is a for loop command , length(theta1) it refers to number of value of theta1.
Here i value is change from 1 to length of theta1.
Let theta 1 have 10 value then value of i changed from 1 to 10 and each time it store one value of theta1.

In the above figure all the coordinates name are mentioned .

x0=0;
        y0=0;
        
        y1=l1*sind(theta1(i));
        x1=l1*cosd(theta1(i));
    
        x2=x1+l2*cosd(Theta2);
        y2=y1+l2*sind(Theta2);
        
        x3=x2+l3*sind(c);
        y3=y2+l3*cosd(c);
        
        x4=x2-l4*sind(c);
        y4=y2-l4*cosd(c);
        
        x5=x4+l5*cosd(c);
        y5=y4-l5*sind(c);
        
        x6=x3+l6*cosd(c);
        y6=y3-l6*sind(c);
         x8=-1;
         y8=0;
         
         x9=1;
         y9=0;

For calulating the coordinate we should know about the variable which are used in to calculate coordinate.
By using of simple trigonmetry and logical operation we can easly calculate the coordinate location.
The above command is written for the locating coordinate of the figure.
first we start the coordinate from (X0,Y0) location.
x2=x1+l2*cosd(Theta2);
y2=y1+l2*sind(Theta2);
Here x1 is the referance point for the x2 and y1 is for the y2.
c=360-Theta2; Here c is a variable , we take this variable to make our calculation easy.

plot([x0 x1],[y0 y1],[x1 x2],[y1 y2],[x2 x3],[y2 y3],[x2 x4],[y2 y4],[x4 x5],[y4 y5],[x3 x6],[y3 y6],[x8 x9],[y8 y9],'linewidth',3); :- This command is written for plot all the line we given.

title('Robotic arm')
xlabel('X-axis')
ylabel('Y-axis')
Here we give our figure title is Robotic arm.
we give xlabel name is x-axis and ylabel as Y-axis.

M(ct)=getframe(gcf)

Here M is a array of figure window and getframe(gcf) means it show the current figure.
movie(M)
videofile=VideoWriter('robo.avi')
open(videofile)
writeVideo(videofile,M)
close(videofile)
This command is written for make a movie in matlab.
robo.avi means that the video will make in avi format .

ERROR FACED WHILE PROGRAMMING :-

The script title should be written only in capital alphabet ,small alphbet, number and underscore otherwise you will get Error when you run the program in MATLAB.
correct way
In MATLAB make sure that the current folder window and Editor window should have same storage path.
correct way
in the time of writting program make sure that the angle unit is in dgree otherwise MATLAB take it in radian then you will get a different output.
correct way
When you calculate a New coordinate make sure that you take the correct reference coordinate point.
correct way