Robotic Arm Lab — Chapter 4 (Forward Kinematics Ultimate)

Robotic Arm Lab

Chapter 4 — Forward Kinematics (FK) Ultimate

What is FK? easy meaning

Forward Kinematics = “Angles → Hand position”

You move sliders (θ1, θ2). Robot computes End-Effector point (x,y,z).

Remember: FK = angles are INPUT. Position is OUTPUT.

Joints (Angles) observe vectors

θ1 (Joint-1)

-180° to 180°

θ2 (Joint-2)

-150° to 150°

Link-1 Length (L1)

0.8m to 2.6m

Link-2 Length (L2)

0.6m to 2.2m

Motion Speed

slow = best learning

Smooth Motion

easing

Hotkeys: R reset • V vectors • T trace • W workspace • G ghost

Visual Modes the “animated explanation”

Vector Reveal

v1 + v2

Ghost Pose

previous pose shadow

End-effector Trace

path line

Workspace Reveal

reachable area

Drag Target Mode

error vector only

FK is being explained by visuals: arrows, ghost, trace, and workspace.

Human Arm Comparison alive, not statue

Show Human Arm

alive mode

Human View

split / ghost

Alive Amount

subtle realism

Humans approximate. Robots calculate precisely. That’s why FK matters.

FK: x=?, y=?

θ1=?, θ2=?

Target error: —

Chapter 4: Forward Kinematics

Meaning: joint angles are input → robot hand position is output.

Watch the arrows: v1 (link-1) + v2 (link-2) = end-effector.

Selected: None

Hover 3D parts for simple explanation. Click to lock selection.

Live FK equation (2-link planar):

—

Easy reading:
• Link-1 makes a triangle using cos θ1 and sin θ1
• Link-2 uses angle (θ1+θ2) because it’s attached to link-1

Try this challenge:

Turn ON Workspace Reveal. Increase L1 & L2. See workspace grow. Then move θ sliders and watch the end-effector trace.

Important line:

“Robot guesses nothing. Robot calculates everything.”