Week 2- 2R Robotic Arm Challenge

Writing program for the forward kinematics of 2R robot,

Step by step explanation of program,

Commands used while writing the program,

• Linspace
• Counter
• For loops
• Plot, label and axis defining
• Movie, video, open, video writer & write video

Given Date,

Theta1 =ꬾ

Theta2 = ꬾ

• Counter is used for getting the no. of frames and counter value is given as ct = ct+1,
• For loop is used to run the program again and again for different values of theta,

1. 2R Robot having 3 joints, 2 lengths

• Fixed Link (X0 Y0)
• Link 1 (X1 Y1)
• link 2 (X2 Y2)
• Length of Link 1 = L1
• Length of Link 2 = L2

1. Defining the length of links of the robots,

• For Fixed Link there are two points as below

X0 = 0

Y0 = 0

• For Link 1 there are two points as below

X1 = L1*cosd(theta1)

Y1 = L1*sind(theta1)

• For Link 2 there are two points as below

X2 = X1+ L2*cosd(theta2)

Y2 = Y1+ L2*sind(theta2)

1. Plotting has done in single line to configure the motion of robot
2. For creating the AVI of robotic configuration current figure handle (gcf)
3. Some other function are written to create an video as per the MATLAB required,

Error faced while writing the program,

1. Got non correct plotting when run the program, used the theta in lower case in for loop, correction done by changing the ‘theta’ to ‘THETA’
2. While running the program got error in ‘write video’ command due to the command not have enough inputs to meet the code, correction by giving the command correctly
3. Some minor error faced like:- spelling mistakes and ‘, : ; etc, all correction done,

link of youtube for animation of forward kinematics of 2R robot,

https://youtu.be/4PFsfHCcBFI

Errors faced as show in screenshots as below,

result

%Kinematics of 2R Rotbot

clear all
close all 
clc

%inputs 
% lenghts of the links 
l1=3;
l2=0.9;

% Angles of the Links
theta1 = linspace(0,90,15);
theta2 = linspace(0,90,15);

% counter 
ct= 1;

% using for loop for diffrent valuve of 'theta',  here i and j are variables 
for i = 1:length(theta1)
    THETA1 = theta1(i);
    for j = 1:length(theta2)
        THETA2 = theta2(j);
        
% Defining the fixed ponint variables of robot 
x0 = 0;
y0 = 0;

% Defining the link1 variables of robot 
x1 = l1*cosd(THETA1);
y1 = l1*sind(THETA1);

% Defining the link2 variables of robot 
x2 = x1 + l2*cosd(THETA2);
y2 = y1 + l2*sind(THETA2);

% Plotting 
plot([x0 x1],[y0 y1],[x1 x2],[y1 y2],'linewidth',2);
axis([-0.1 4 -0.1 4.5]);
xlabel('X_axis')
ylabel('Y_axis')
grid on 

m(ct) = getframe(gcf);
ct= ct+1;
    end 
end 

% Creating animation
movie(m)
videofile = VideoWriter('Kinematics_of_2R_robot','Uncompressed AVI');
open(videofile)
writeVideo(videofile,m)
close(videofile)