Forward kinematics of a 2R robotic arm.

The above diagram illustrates a 2R Robotic arm. A 2R robotic arm consists of two links. Both the links are connected to each other as shown in the figure. One end is connected to a base and the other is connected to a manipulator.

The following program is used to simulate the forward kinematics of a 2R robotic arm. As described in the program, the first five lines of the code is used for predefined values.

A 'for' loop is used to simulate the kinematics of a robotic arm across the 90 degrees and assess the manipulator. Also, the code for the animation of plot is also written in the 'for' loop.

% A program to simulate the forward kinematics of a 2R Robotic Arm and an animation plot.

% inputs
l1=1;   % length of link 1
l2=0.5; % length of link 2

theta1=linspace(0,90,10); % Angle made by link 1 with the horizontal
theta2=linspace(0,90,10); % Angle made by link 2 with the horizontal

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

To convert the animation of the above plot in to a movie with .avi extension can be done using the code below.

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

During the programming, the below occured once because 'ct' is a variable in this program which has to be defined before the 'for' loop. Not defining a variable will result in such an error.