Week 2- 2R Robotic Arm Challenge

2R ROBOTIC ARM CHALLENGE

AIM: Program to simulate the forward kinematics of a 2R Robotic Arm.

SOFTWARE USED: MATLAB R2020a

SCHEMATIC DIAGRAM:

2R Robotic arm (AutoCAD 2D)

FACTORS INVOLVED:

Length of Link 1 (l1)=10 meter

Length of link 2 (l2)= 5 meter

Angle of Link1 wrt. horizontal = theta1

Angle of Link2 wrt. horizontal = theta2

Coordinate Point	Value
x0	0
y0	0
x1	l1*cosd(theta1)
y1	l1*sind(theta2)
x2	x1+l2*cosd(theta2)
y2	y1+l2*sind(theta2)

PROGRAM:

clear all  %close the workspace window
close all  %close the figure window
clc        %close the command window in every each time we execute the program

l1 = 10; %length of link 1
l2 = 5;  %length of link 2

theta1 = linspace(0,90,30) %angle assigned to theta1 from 0 to 90 in a 30 evenly spaced sequence
theta2 = linspace(0,90,30) %angle assigned to theta2 from 0 to 90 in a 30 evenly spaced sequence

ct=1 %counter value is assigned to 1
for i = 1 : length(theta1) %included a for loop and introduced a variable called 'i' and assigned with different positions (here it's 1 to 30)
    THETA1 = theta1(i)     %in every iteration a value for angle will assign to THETA1 with respect to the position
    
    for j = 1 : length(theta2)  %included a for loop and introduced a variable called 'j' and assigned with different positions (here it's 1 to 30)
        THETA2 = theta2(j)      %in every execution a value for angle will assign to THETA2 with respect to the position
       

x0 = 0;  %x-coordinate of the base point of first link
y0 = 0;  %y-coordinate of the base point of first link

x1 = l1*cosd(THETA1);   %x-coordinate of the end point of first link and the base point of the second link

y1 = l1*sind(THETA1);   %y-coordinate of the end point of first link and the base point of the second link

x2 = x1+l2*cosd(THETA2);  %x-coordinate of the end point of the second link
y2 = y1+l2*sind(THETA2);  %y-coordinate of the end point of the second link


plot([x0 x1], [y0 y1],[x1 x2], [y1 y2],'linewidth',3) %to plot the required figure by providing line width
title('FORWARD KINEMATICS OF A 2R ROBOTIC ARM') %title of the plot
axis([-1 15 0 15])  %values of origin and end limits for the x and y axis
grid on  %to display grid in the plot
xlabel('x axis') %name of x axis 
ylabel('y axis') %name of y axis 
pause (0.008)    %to pause the iteration for every 0.008 seconds
M(ct) = getframe(gcf)  %Each and every frame which is ct is saved to an array called 'M'
ct =ct+1               %to change the counter value to next value after each iteration of the loop

    end  %end the second for loop

end      %end the first for loop

movie(M) %to generate a movie with all those frames which is saved in an array called 'M'
videofile = VideoWriter('challenge_forward_kinematics.avi','Uncompressed AVI'); 
%VideoWriter is the command to create videofile, followed by including file name and profile inside a bracket and allocated it to videofile 
open(videofile) %to open the videofile for writing
writeVideo(videofile,M) %writes the image data 'M' to the videofile
close(videofile) %close the videofile

PROGRAM RESULT:

1. A video file regarding the animation of 2R Robotic Arm is created.
2. Successfully uploaded the required file in the youtube.

YOUTUBE LINK: https://youtu.be/JjAD76q_RnY

ERRORS FACE WHILE PRORAMMING:

I had made a mistake while coding regarding the command to write data from an array to the videofile associated with the 'videofile'(see in line:48).

The right way to input the command is 'writeVideo', the letter 'V' should be uppercase.

EXPLANATION FOR CODE:

• Started the program using clear all, close all and clc.
• Provided the input values of l1 and l2.
• Provided the values for theta1 and theta2 by the linspace command from 0 to 90 degree in a 30 evenly spaced sequence.
• Provided the ct (counter) value. Here I provided 1.
• 'for' command is used to initialize the 'for loop' of the first link and again a for loop command is inroduced for the for loop of the second link.
• Assigned the values of x0,y0,x1,y1,x2 and y2 as shown in the program.
• By the 'plot' command all coordinate values are plotted by providing neccessary line width.
• 'title' command is used to introduce the title for the plot.
• Provided the axis size by 'axis' command.
• Switch the grid inside the plot by 'grid on' command.
• Name of x-axis and y-axis are provided by the 'xlabel' and 'ylabel' command respectively.
• 'pause' command is used to pause the execution for prescribed amount of time. Here in the program it is 0.008 sec.
• Each figure after completing the execution is saved in a file called 'M'.
• An increment for ct is provided at the end of each execution. Here the ct will increase +1 after each execution.
• After completing the two loops, the end command is entered twice.
• 'movie' command is used to create the movie by using the frames which was saved in the file 'M'.
• 'VideoWriter' command is used to create the videofile, followed by a bracket a file name and profile is entered.
• Use the 'open' command to open the video file for writing.
• 'writeVideo' is used for write the video. Here its write it into 'M'.
• Then 'close' command is used to close the videofile.