Week 2- 2R Robotic Arm Challenge

Matlab program to simulate the forward kinematics of a 2R Robotic Arm

The length of the two arms are taken respectively 

     l1 = 1m

     l2 = 0.5m

     the workspace angles are taken between 0 and 90 degrees for each arms

I will present the code now

clear all
close all
clc


%kinematics of robotic arm with for loop
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 2 0 2])
       
        M(ct) = getframe(gcf);
        ct=ct+1;
        
        

    end
end

movie(M)
videofile = VideoWriter('robotiC_arm_with_loops_2.avi','Uncompressed AVI');
open(videofile)
writeVideo(videofile,M)
close(videofile)

 clear all - used for clearing the variables in workspace

close all - used fo closing the existing plots , graphs

clc - clears the command window

Lengths are takesn as 1m and 0.5m for L1 and L2 respectively

Angle range ; 

   The theta1 has a range of value ,angles from 0 to 90 degree which is taken by linspace command ranging 10 degrees between them for 10 values

  same way theta2 also taken 

  theta1 values are the angles of arm 1 1 L1  

  theta2 values are the angles of arm 2 L2   

  here FOR loops are used in this program  to allocate the angle values of the arms for each case

  as 

   theta1 = linspace(0,90,10) gives 10 values namely

   theta1 = [0 10 20 30.....90] - 10 values

   the FOR loops are used

   FOR i = 1:length(theta1)

      THETA1 = theta1(i)

        here  i repeats 10 times  by assigning value for THETA1. These values are taken from theta1 which is from the array [ 0 10 20 30 40 50 60 70 80 90] so THETA1 (variable) has a value of angles from 0 to 90 degrees. This corresponds to arm 1 

same way for the arm 2 FOR loops are programmed, but here as the arm 2 corresponds to every action of arm 1 again a FOR loop is given inside the loop itself . so that the arm 2 which will have 10 values of angle correspomds to 10 values of angle already given to arm 1 . 

So that totally there will be 10*10 output position of the Robotic arms.

THE PROBLEM;

  Initially the coordinates are set to origin  i.e x = 0 and y = 0

  the arm 1 would be determined by giving coordinate values of x and y with the help of trigonometry 

  so x1 = L1cosd(THETA1)

      y1 = L1sind(THETA1) are given  

   same way arm 2 coordinates are determined 

   arm 2 starts after arm 1 

      x2 = x1 + L2cosd(THETA2)

     y2 =  y1 + L2sind(THETA2) are given  

  THETA1  and THETA2 are the variables here assigning angle values for arm 1 and arm 2 respectively. 

PLOTTING;

 plot([x0 x1],[y0 y1], [x1 x2], [y1 y2]) gives us the plot for the coordinates x0 x1 ,y0 y1, and x1 x2, y1 y2

the figures of the plot are stored in a variable called M i.e M(ct) 

 M(ct) = getframe(gcf)  this is given that the figures ,plots, frames that is being generated must be captured and asiigned to the variable M

then the whole code is incremented 

These all codes comes under FOR loop as the variables mentioned above depends on the angular value of arm 1 and arm 2 andd corresponds to it.

VIDEOFILE;

The plots(totally 100 images) which is inside the variable M is commanded to form a video by giving a command video(M)

The video file must be in AVI form so

 videofile = VideoWriter('robotic_arms_with_loops_2.avi','Uncompressed AVI')

is given which means that ,this videofile contains video in AVI format so a file is initially created and the file is opened using the command 

 open( videofile) 

and the video is played by the command

 writeVideo(videofile,M) which consists the video M in AVI file format.

 close(videofile)

ends the video 

https://youtu.be/OKE6oHMqR1k

here is my link to youtube video of robotic arm with 2 loops.