Week 2- 2R Robotic Arm Challenge

Aim to - simulate the forward kinematics of a 2R Robotic Arm using Matlab.

in this, we are going to write a program to solve the forward kinematic of a 2arm robotic arm manipulator.

solution-

• calculate the position of link 1
• calculate the position of link 2

the robot consists of 2 links 2 axis ponts and manipulator connected at the end of the second link

the first axis connected to the base and the 1st link

and the second axis is connected to the 1st link and the 2nd link

inputs

let us consider 1st link length as

l1=1

and 2nd link as

l2=0.5

1st axis as

theta1

2nd axis as

theta2

here forward kinematic is used to calculate the position of the end-effector of the specific value of the joint parameters

in this, we have to find the value of the x1,y1,x2,y2

x1=l1*costheta

y1=l1*sintheta

x2=y1+l2*costheta

y2=y1+l2*sintheta

writing of program

%calculate the forward kinematic of 2r robotic arm
clear all 
close all
clc

% inputs
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([-0.5 1.5 0.1 1.5])
        pause(0.03)
        M(ct) = getframe(gcf);
        ct= ct+1;
    end
end

%making of movie

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

the output of the program

video of the robotic arm

coding

• to get started we have to open a new file
• whenever we start a new program it is good practice to include some commands
• input variables are taken
• linspace command is used to get the variables between 0:90 without typing manually
• and forloop command is used b using this command no need of changing theta value manually
• the formula has been inserted
• plot command is used to plot the variable angels of the robotic arm
• and it is converted to the animation video

errors faced while writing the program

• confused between the theta and THETA
• while writing the forloop command I and j was miss placed