Week 2- 2R Robotic Arm Challenge

AIM

To simulate the forward kinematics of a 2R Robotic Arm

OBJECTIVE

Write a program to simulate forward kinematics of a robotic arm

To Create an animation and movie of the robotic arm through the obtained plot.

THEORY

Robotic arm:A robotic arm is a type of mechanical arm, usually programmable, with similar functions to a human arm; the arm may be the sum total of the mechanism or may be part of a more complex robot. The links of such a manipulator are connected by joints allowing either rotational motion (such as in an articulated robot) or translational (linear) displacement. The links of the manipulator can be considered to form a kinematic chain. The terminus of the kinematic chain of the manipulator is called the end effector and it is analogous to the human hand. However, the term "robotic hand" as a synonym of the robotic arm is often proscribed.

INPUTS

Length of link 1 (L1)=1

Length of link 2 (L1)=0.5

Co-ordinates of link 1 and 2

x0=0

y0=0

x1=l1*cosd(thetha1)

y1=l1*sind(thetha2)

x2=x1+l2*cosd(thetha2)

y2=y1+l2*sind(thetha2)

WHERE,

x0,y0=starting points of link1

x1,y1=ending points of link1/starting point of link2

x2,y2=ending points of link2

l1=length of link1

l2=length of link2

thetha1=angle made by link1 with respect to x-axis

thetha2=angle made by link2 with respect to x-axis

HERE d is taken after cos and sin beacuse to represent it in 'degrees'

PROGRAM/CODE

clear all
close all
clc

%inputs
L1=1;
L2=0.5

thetha1=linspace(0,90,10);
thetha2=linspace(0,90,10);
ct=1;
for i=1:length(thetha1)
    THETHA1= thetha1(i);
  for  j=1:length(thetha2)
    THETHA2=thetha2(j);
    x0=0;
    y0=0;
    x1=L1*cosd(THETHA1);
    y1=L1*sind(THETHA1);

   x2=x1+L2*cosd(THETHA2);
   y2=y1+L2*sind(THETHA2);
   % plotting

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

CODE EXPLANATION

Start with the CLEAR ALL,CLOSE ALL AND CLC COMMAND

Assign the inputs for LENGTH OF LINK1 and LINK2

Assign THETHA values

ct represnts count

for loop is used to run the code again and again where i and j is taken

then using the mathematical relation

we need to find x1,y1 and x2,y2

plotting to be done using plot command

co-ordinates for axis is given using axis command

pause command is used in animation to get tge graph much more smoother

m(ct) represents the movie and the frame count

get frame command is used

for every for Loop end need to be given

to create a movie asign movie(m)

then videofile that will be in video format

give the movie name using .avi which is standard form and Uncompressed AVI

type as open file ,writeVideo and close so that the movie will be saved in the folder and can access it .

RESULTS/OUTPUT

https://youtu.be/VQ4nhY1R2G0

CONCLUSION

A practical scenario regarding the functioning of the 2R robotic arm and its workspace has been experienced by simulating forward kinematics with a program in MATLAB.