Hi there ! Hi Admin ! Hi guest !

I have a question for robot arm desaigner (excel sheet: Robot Arm Designer v1) especially about forward kinematics.

On Robot Arm Designer v1, there have 2 joints with equations :

Joint 0 (with x and y at base equaling 0):

x0 = 0

y0 = L0

Joint 1 (with x and y at J1 equaling 0):

cos(psi) = x1/L1 => x1 = L1*cos(psi)

sin(psi) = y1/L1 => y1 = L1*sin(psi)

Joint 2 (with x and y at J2 equaling 0):

sin(theta) = x2/L2 => x2 = L2*cos(theta)+x1

cos(theta) = y2/L2 => y2 = L2*sin(theta)+y1

What if I made equation for 3 joints?

And then I made equation for 3 joints like this :

Joint 3

x3 = L3*cos(theta)+x1+x2

y3 = L3*sin(theta)+y1+y2

Was it right ?

Please help me.

oh one more.On excel sheet, value of theta (x2 and y2) is theta1 + theta2. Why ?