2R Robotic Arm Challenge

# Attempt 1

You scored 50/50 in this challenge. Please see the below table for details

Requirement	Explanation	Maximum Marks	Marks Obtained
Code	Code should be attached with comments	20	20
Outputs	Output plots/videos must be attached with proper plot labels and title	10	10
Explanation	Code and outputs must be explained in detail	20	20

Grading Comments:

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Aim :- To Write a program in Matlab to simulate the forward kinematics of a 2R Robotic Arm.

Objective :-

• Write a program to simulate forward kinematics of a 2R Robotic Arm
• To create a Movie/Animation from the plots obtained from the program

Theory:-

-A robotic arm is a type of mechanical arm, usually programmable , with similar functions to a human arm; the arm may be the sum total of the mechanism or may be part of a more complex robot. The links of such a manipulator are connected by joints allowing either rotational motion (such as in an articulated robot) or translational (linear) displacement. The links of the manipulator can be considered to form a kinematic chain. The terminus of the kinematic chain of the manipulator is called the end effector and it is analogous to the human hamd.

-In this project, we consider a 2R robotic arm. A 2R robotic arm represents a robotic arm with two rotations. i.e. it has two links which rotate or work over a two-dimensional plane with each of links having a single degree of freedom.

-Also, both the links are restricted to a 90° rotation with respect to the axes. Fig below shows the 2R robotic arm having many parts as described.

• Let , L1 & L2 be the lengths of the link-1 & link-2 Respectively.
• Let , θ1">θ1be the angle formed by link-1 with horizontal.
• Let , θ2">θ2 be the angle formed by link-2 with horizontal.
• Let , the starting and end co-ordinates of link-1 to be (x₀, y₀) and (x₁, y₁)
• Let , the starting and end co-ordinates of link-2 to be (x₁, y₁) and (x₂, y₂)

Code Explanation :-

• Programing Language used Matlab Online
• starting the program by using comments
• Providing the input variables like
• Predefining the length/values of the robotic arms, i.e. l1and l2
• Providing the values for theta-1 & theta-2 using linspace command for theta=0 to 90 degrees for 12 values
• Providing the Cr (compression ratio ) value as a specific digit.
• Now Using ‘for’ commandfor iterating the values of the desired variable.
• Again using ‘for’ commandfor providing movement to the second robotic arm.
• Providing the eqn for the x1,y1,x2,y2 or say Defining the coordinates of both the robotic arms.
• Plotting all the coordinate values and providing the axis no.
• Using the pause command to make the plot look realistic
• Incrementing the cr or compression ratio value by +1 each time it executes for loop.
• All figures are assigned to a variable M, one at a time usingcr
• Ending the ‘for’ loop twice .
• using movie commandis to combine all the figures saved in the M file to make an animation/movie
• At end saving the movie in .avi format.

Matlab Code :-

% Program for 2R Robotic Arm Challenge
clear all 
close all
clc

%Inputs
 l1=1;
 l2=0.5;
 theta1=linspace(0,90,12);
 theta2=linspace(0,90,12);
 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',2)       
 axis([-0.1 2 0 1.5])       
 pause(0.01)       
 M(ct)=getframe(gcf);       
 ct=ct+1;    
 end
 
end

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

Errors & Command window Exicution :-

- No Errors were found during exicution

- use of semi-colon (;) in coding results in no output in command window

Result/Conclusion :- Thus we have simulated 2R robotic arm by using the matlab programming and also created a Movie/Animation from the plots obtained from the program

- below is the link given for the program output for movie/animation of a 2R robotic arm

https://youtu.be/tpzkg-FYyQk