Modeling Robot Arm reach and motion

CAN YOU ADD COMMENTS FOR THE BELOW MATLAB CODE (WHAT EACH STEP DOES):

close all

clear all

alpha4 = 0:15:75;

alpha3 = -45;

alpha2 = -45:15:45;

alpha5 = -45:10:45;

Arm43 = 8;

Arm32 = 5;

Arm21 = 3;

[ALPHA4, ALPHA3,ALPHA2,ALPHA5] = ndgrid(alpha4,alpha3,alpha2,alpha5);

longdist = Arm43*cosd(ALPHA4)+Arm32*cosd(ALPHA4+ALPHA3)+Arm21*cosd(ALPHA4+ALPHA3+ALPHA2);

height = Arm43*sind(ALPHA4)+Arm32*sind(ALPHA4+ALPHA3)+Arm21*sind(ALPHA4+ALPHA3+ALPHA2);

z = height;

x = cosd(ALPHA5).*longdist;

y = sind(ALPHA5).*longdist;

%plot3(x(:),y(:),z(:),'.')

%axis equal

%calculate distal line segment

firstArmZ2 = Arm43*sind(ALPHA4);

firstArmX2 = cosd(ALPHA5).*(Arm43*cosd(ALPHA4));

firstArmY2 = sind(ALPHA5).*(Arm43*cosd(ALPHA4));

secondArmZ2 = Arm43*sind(ALPHA4)+Arm32*sind(ALPHA4+ALPHA3);

secondArmX2 = cosd(ALPHA5).*(Arm43*cosd(ALPHA4)+Arm32*cosd(ALPHA4+ALPHA3));

secondArmY2 = sind(ALPHA5).*(Arm43*cosd(ALPHA4)+Arm32*cosd(ALPHA4+ALPHA3));

thirdArmZ2 = height;

thirdArmX2 = x;

thirdArmY2 = y;

figure(2)

hold on

for tmp1 = 1:length(firstArmZ2(:))

plot3([0 firstArmX2(tmp1)],[0 firstArmY2(tmp1)],[0 firstArmZ2(tmp1)],'k-')

plot3([firstArmX2(tmp1) secondArmX2(tmp1)],...

[firstArmY2(tmp1) secondArmY2(tmp1)],...

[firstArmZ2(tmp1) secondArmZ2(tmp1)],'b-')

plot3([secondArmX2(tmp1) thirdArmX2(tmp1)],...

[secondArmY2(tmp1) thirdArmY2(tmp1)],...

[secondArmZ2(tmp1) thirdArmZ2(tmp1)],'color',[0.5 0.5 0.5])

end

% create a box

x1 = 10;

x2 = 20;

x3 = 20;

x4 = 10;

y1 = -15;

y2 = -15;

y3 = 15;

y4 = 15;

z = 1;

plot3( [x1 x2 x3 x4 x1], [y1 y2 y3 y4 y1], [z z z z z])