Week 2- 2R Robotic Arm Challenge

https://drive.google.com/file/d/1ZA3N7WGmmGm72Qp8GrKSYxj6QNDU3TSB/view?usp=sharing

clear all
close all
clc

% forward kinematic of robotic arm

% inputs

l1= 1   (Length of link 1)
l2= 0.5 (Length of link 2)

theta1=45;  (Angle of link 1 with x axis)
theta2=30;  (Angle of link 2 with x axis)

% coordinates

x0=0; (Starting point of link 1)
y0=0;  (Starting point of link 1)

x1=l1*cosd(theta1); (Ending point of link 1 & Starting point of link 2)
y1=l1*sind(theta1);  (Ending point of link 1 & Starting point of link 2)


x2=x1+l2*cosd(theta2); (Ending point of link 2)
y2=y1+l2*sind(theta2);  (Ending point of link 2)


%plotting

line([x0 x1],[y0 y1],'linewidth',3,'color','b'); (plot of link 1)

line([x1 x2],[y1 y2],'linewidth',3,'color','r');  (plot of link 2)

explanation:

First I done these coding and plotted a graph and checked how it came.That graph also I attaching with this .

Then I opned a new window for creating array of angles and creating a movie of the movements of links.

In that new link first I done coding like below:

clear all
close all
clc

% inputs
l1=1;
l2=0.5;

theta1=linspace(0,90,10); (Array of angles between 0 & 90deg with 10 intermediate 
                           points)
theta2=linspace(0,90,10);  (Array of angles between 0 & 90deg with 10 intermediate 
                           points

for i=1:length(theta1)    (opened for loop with loop operator 'i')
    THETA1=theta1(i);     ( Assigned that to a variable 'THETA 1')
    for j=1:length(theta2) (Opned another for loop with loop operator 'j'))
        THETA2=theta2(j);   ( Assigned that to a variable 'THETA 2')
        disp('hello') 
    end
end

Explanation:

Here I opened 2 for loops with loop with loop operators'i' &'j' beacuse here for each 'theta 1', 'theta 2' changes 10 times. So, total 100 outputs should come and that I checked by printing 'hello'.I got 'hello' printed 100 times and that screenshot also I am attaching along with this.

Then I removed hello command from there and pasted coordinate commmands from previous window and then it became'

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

line([x0 x1],[y0 y1],'linewidth',3,'color','b');  (Command for ploting link 1)

line([x1 x2],[y1 y2],'linewidth',3,'color','r');   (Command for ploting link 2)

end
end

Explanation:

here I plotted link 1 & link 2 with all angles and I got a plot with all agles for both links.I am attaching that graph along with this.Here for each angle of link1 , angle of link 2 varies 10 times.


But that plot was not good and we need to create a movie with the positions of both linlks. So, I bring some changes in that coding as given below:

Here I am writing only the changed portion of program and remaining portion of program remains the same as above.

%plotting
hold on  (it will help to show both links togther in plot)
plot([x0 x1],[y0 y1],[x1 x2],[y1 y2],'linewidth',3);  (Command for plotting both links)
pause(0.03);  (Here we are giving time for the pausing each frame)
ct=ct+1       ( this is for increasing each figure)


explanation:

After this change in coding I got a graph with all positions and plotting of that links we could see as an animation & that graph also I am attaching along with   this.

But still I didn't get a perfect movie from that, so I tried to bring some another changes in that coding like below:

%plotting
hold on
plot([x0 x1],[y0 y1],[x1 x2],[y1 y2],'linewidth',3);
pause(0.03);

 M=getframes(gcf);
 ct=ct+1

    end
end

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

Explanation:

Here I got an error like below:

Undefined function or variable 'getframes'.

Error in challenge_robotic_arm_final (line 31)
 M=getframes(gcf);


Agai I tried to solve this error and finally I changed codes like below:


 %plotting
hold on
plot([x0 x1],[y0 y1],[x1 x2],[y1 y2],'linewidth',3);
pause(0.03);

 M=getframe(gcf);
 ct=ct+1

    end
end

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


Explanation:

Now, I got plot with all angles like a movie and that plot also I am attaching with this but still some shown as below:


Warning: No video frames were written to this file. The file may be invalid. 
> In VideoWriter/close (line 278)
  In challenge_robotic_arm_final (line 41) 


I thought my video files are not saving properly and again I tried to solve this and finally I end up with these changes 

%plotting
hold on
plot([x0 x1],[y0 y1],[x1 x2],[y1 y2],'linewidth',3);
pause(0.03);

 M=getframe(gcf);  (Here we are assigning each fram into a variable called  'M')
 ct=ct+1

    end
end

movie(M)  (For making a movie with all of that frames)
videofile=VideoWriter('forward_kinematic.AVI','Uncompressed avi');
  (Creating a videofile for dumping all that frames after execution)

open(videofile); (Open that videofile)
writeVideo(videofile,M); (Writing all frames into that videofile)
close(videofile);  (Closing that videofile)

Explanation:

Now I got an animation video of position changing of both links and there is no error shown in the command window.So I am attaching that final plot also along with this.

Here 'forward_kinematic.AVI' is the file name & 'Uncompressed avi' is the profile also.


>> Link for the final video also attaching along with this