Work out forward kinematics position instantly with clear inputs, formula shown and shareable results.
Forward kinematics chains the links: x = L1 cos(t1) + L2 cos(t1 + t2), y = L1 sin(t1) + L2 sin(t1 + t2). Note the second angle is relative to the first link, which is the usual robot convention, so the tool orientation is the sum of the joint angles.
Two-link FK
x = L1 cos(t1) + L2 cos(t1+t2); y = L1 sin(t1) + L2 sin(t1+t2)
Relative here: theta2 is measured from the first link, not from the base frame. Mixing the conventions is the most common source of kinematics errors.
It is a direct evaluation with a unique answer. Inverse kinematics must solve for angles and generally has multiple or no solutions.