Week 3.2 - 2R Robotic Arm Challenge

Ans for Challenge Week 3.2 2R Robotic arm challenge

Aim:- To write a program to simulate the Forward kinematics of a 2R Robotic arm.

Objective:

• To solve and understand the behavior of Translatory or rotary movement of a 2R Robotic arm
• To simulate the manipulator in Matlab
• To create a Movie/Animation video of a 2R Robotic arm manipulator
  
  

Theory:

A robotic arm is a type of mechanical arm, usually programmable, with similar functions to a human arm. The links of such a manipulator are connected by joints allowing either rotational motion or translational (linear) displacement.

A 2R robotic arm represents a robotic arm with two rotations. i.e. it has two links that rotate or work over a two-dimensional plane with each of the links having a single degree of freedom

If we are able to find out how the robotic arms move, we could specify the application of a robot. That is we can find out it's workspace (The possible location the robot can reach).

For a 2R Robotic Arm, there are two links and two rotational joints. Link 1 makes an angle θ1">θ1 with the x-axis and link 2 makes θ2">θ2 with the x-axis. Let's assume the link length to be l1 andl2">l1 and l2 respectively. First, we need to specify the position of the manipulator if θ1 and θ2 are given/known.

Input Parameters:

l1 = length of the link-1 (Hinged or pivoted at base)

l2 = length of the link-2 (Jointed with link-1)

(x0,y0) = Starting point of link-1

(x1,y1) = End point of link-1/Starting point of link-2

(x2,y2) = End point of link-2

theta1 = Angle made by the link-1 with x-axis (Horizontal)

theta2 = Angle made by the link-2 with x-axis (Horizontal)

Program Code:

% A Program for Forward Kinematics of a 2R Robotic arm sitmulator
clear all
close all
clc

% Inputs 
l1 = 1.25;    % Assuming length of link-1 
l2 = 0.65;    % Assuming length of link-2  

% Set of angles for the movement of robotic arms
theta1 = linspace(0,90,10); 
theta2 = linspace(0,90,10); 
ct = 1;  % counter with starting value as 1

for i = 1:length(theta1)  % Iterating i from 0 to 10 as theta1 has 10 values
    Theta1 = theta1(i);  % Storing iterated values of i in Theta1
    
    for j = 1:length(theta2) % Iterating j from 0 to 10 as theta1 has 10 values
        Theta2 = theta2(j);  % Storing iterated values of j in Theta2 
       
        % Co-ordinates of staring points of first arm
        x0 = 0;
        y0 = 0;
        
        % Co-ordinates of end point of 1st arm / Starting point of 2nd arm
        x1 = l1*cosd(Theta1);
        y1 = l2*sind(Theta2);
       
        % Co-ordinates of end point of 2nd arm
        x2 = x1+l2*cosd(Theta2);
        y2 = y1+l2*sind(Theta2);
        
        % Plotting
        
        % co-ordinates of arms assigned over a set of theta1 and theta2
       plot([x0,x1],[y0,y1], [x1,x2],[y1,y2],'linewidth',2.5)
       
       % The limits of x-axis and y-axis
       axis([-0.1 2 0 2.5])
      
       % To cease the animation from jumping between subsequent figures
       pause(0.02)
       
       % collecting frames of figures to comprise a movie/animation
       M(ct) = getframe(gcf);
       ct = ct+1;
    end
end

% To make a movie of the collected frame
movie(M)

% Saving the movie in '.avi' format
videofile = VideoWriter('forward_kinematics.avi','Uncompressed AVI');
open(videofile)

% writing the movie in the videofile created 
writeVideo(videofile,M)
close(videofile)
           

Errors Occurred During Execution:

- No Errors were found during the Execution

- Error Occurred only due to spelling mistakes or missing semicolons after completing the line

- Below Error Occurred due to small caps mistake in file naming

Results & Conclusion:

Thus we have simulated the 2R Robotic arm by using Matlab programming and also created a Movie/Animation from the plots obtained from the program

- Below link is given for the Movie/Animation of a 2R Robotic arm Simulator

https://youtu.be/VePfCCvE2AA