Week 2- 2R Robotic Arm Challenge

Aim : Write a code in Matlab to simulate the forward kinematics of a 2R Robotic Arm, as shown in the video. Create an animation file and upload google drive.

Objective : In this challenge we learn how to fined different angle or conditions robotic arm coordinate i.e we simulate degree of freedom of arm and also find thire coordinates according to its angle and crate a animation file by using various matlab commands.

Description :

here is we write a code for 2 link or arm robotic arm and create animation video 

before writting the code predifend the initial inputs such as link length, angle etc.

two link arm so we select 2 length for two arm 

inputs

select link length

link1 = L1=0.8 m
link2 = L2=0.6 m

after selecting link length we define angle here is we simulate the forward kinematic of 2R robotic arm for diifernt angle so we select 0 to 90 degree in matlab 'd' is represent degree so after sin or cos we noted d (sind or cosd ) otherwise result get in radiant and `theta`symbol not insert in code so we insert as theta in the code we get differnt angle 0 to 90 10 value it is represent as below 
theta1 = linspace(0,90,10)
theta2 = linspace(0,90,10) 

so we get two angle for two link we select same value for two links 

after that we select initial coordinates
x0 = 0
y0 = 0

done this input and type as per matlab coding languge 

after that we used 2 for loop for two angle selection theta1 and theta 2 and put this value in formula for finding length of link

by use i and j variable complete the for loop as show in below 

for i = 1:length(theta1)
THETA1 = theta1(i)
for j = 1:length(theta2)
THETA2 = theta2(j)

here is we find x1 link and x2 also y1 and y2 

formula 

link1 x and y coordinate

x1 = L1*cosd(THETA1)
y1 = L1*sind(THETA1)

link2 x and y coordinate
x2 = x1 + L2*cosd(THETA2)
y2 = y1 + L2*sind(THETA2)

for link two we only change just add x1 and y1 values

after comolete aove all thik we using plot command and creat a animation and also used videowriter command and save video 

plot([x0 x1],[y0 y1],[x1 x2],[y1 y2],'LineWidth',3,'color','r');
axis([-0.1 1.5 0 1.5])
pause(0.03);
M(ct) = getframe(gcf)
ct = ct+1
end
end

by using two end we close both for loop after that type code for saving video file in .avi format 

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

Details Code 

clear all
close all
clc

% Robotic arm two link

% inputs
% select link length
L1=0.8;
L2=0.6;
theta1 = linspace(0,90,10)
theta2 = linspace(0,90,10)

% initial coordinates 
x0 = 0;
y0 = 0;

ct=1;
for i = 1:length(theta1);
    THETA1 = theta1(i);
    for j = 1:length(theta2);
        THETA2 = theta2(j);
        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,'color','r');
axis([-0.1 1.5 0 1.5])
pause(0.03);
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);

Result 

animation video link 

https://drive.google.com/file/d/1RW15PINBUeZaghlCdboYrDI-iqKjtnDp/view?usp=drivesdk

Error during cration of code

1. unrecognised function or variable 'theta'

this error is shown in command window during 1st time run the the program in line 20 they show

THETA = theta(i)

this error occurce due to wrong typing we correct it show in below 

instead of only theta(i) we write a theta1(i) and also theta2(j) and solve this error 

screenshot of error 

 

2. the specified profile is not valid 

this error show in command window in line 44 this error cause of i write instead of .avi write a MP4 so matlab so this error so i was type a .avi in MP4 athan slove this error 

screen shot of error

3. unrecognised function or variable 'Videofile'

this error in line 45 this error due to in word of 'Videofile' v is small letter is required i was type capitale letter so this error occurce 

screen shot of error