Crude code for a 3 link RRR robot given DH params:
figure;
h = plot3(0,0,0);p = get(h,'Parent');xlim(p,'manual');
xlim(p,[0 2]);ylim(p,'manual');ylim(p,[0 2]);zlim(p,'manual');
zlim(p,[0 2]);axis vis3d;grid on;
point1.x =0;point1.y = 0;point1.z = 0;
point2.x = 0;point2.y = 0;point2.z = 1;
point3.x = 0;point3.y = 0;point3.z = 1;
point4.x = 2;point4.y = 0;point4.z = 1;
l= line([point1.x, point2.x],[point1.y,point2.y],[point1.z,point2.z],'Color','r','LineWidth',4);
l1 = line([point2.x, point3.x],[point2.y,point3.y],[point2.z,point3.z],'Color','b','LineWidth',4);
l2 = line([point3.x, point4.x],[point3.y,point4.y],[point3.z,point4.z],'Color','g','LineWidth',4);
pause(0.5);
theta2 = 30;
theta3 =0;
for theta1 =70:-1:0
[point2,point3,point4] = fromDHandTheta(theta1,theta1,theta1); %(each individual theta)
set(l,'ZData',[point1.z,point2.z],'YData',[point1.y,point2.y],'XData',[point1.x,point2.x]);
set(l1,'ZData',[point2.z,point3.z],'YData',[point2.y,point3.y],'XData',[point2.x,point3.x]);
set(l2,'ZData',[point3.z,point4.z],'YData',[point3.y,point4.y],'XData',[point3.x,point4.x]);
hold on;
plot3(point4.x,point4.y,point4.z,'xk');
pause(0.1);
end
end
function [point2,point3,point4] = fromDHandTheta(theta1,theta2,theta3)
% D-H Params:
% N Theta Alpha dN rN
% 1 theta1 alpha1 0 0
% 2 theta2 alpha2 1 0
% 3 theta3 alpha3 1 0
s1 = [0;0;0]; % from dN and rN
s2 = [1;0;0];
s3 = [1;0;0];
alpha1 = 90;
alpha2 = 0;
alpha3 = 0;
pointa = returnUfromTheta(theta1)*returnVfromAlpha(alpha1)*s1 + [0;0;1]; % [0;0;1] is orig position
pointb = returnUfromTheta(theta1)*returnVfromAlpha(alpha1)*returnUfromTheta(theta2)*returnVfromAlpha(alpha2)*s2 + pointa;
pointc = returnUfromTheta(theta1)*returnVfromAlpha(alpha1)*returnUfromTheta(theta2)*returnVfromAlpha(alpha2)*...
returnUfromTheta(theta3)*returnVfromAlpha(alpha3)*s3 + pointb;
point2.x = pointa(1); point2.y = pointa(2); point2.z = pointa(3);
point3.x = pointb(1); point3.y = pointb(2); point3.z = pointb(3);
point4.x = pointc(1); point4.y = pointc(2); point4.z = pointc(3);
end
function U = returnUfromTheta(theta)
U = [ cosd(theta), -sind(theta), 0;...
sind(theta), cosd(theta), 0 ;...
0, 0, 1];
end
function V = returnVfromAlpha(alpha)
V = [ 1, 0 ,0;...
0, cosd(alpha), -sind(alpha);...
0, sind(alpha), cosd(alpha)];
end
