Do I need to install anything?

No. It runs in any modern browser, free, with no account required.

For Students · Inverse Kinematics

Inverse Kinematics for a quadruped

Built for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition. Simulate a quadruped live below — adjust the inputs and watch it respond, right in your browser.

Inverse KinematicsLive

target → joint angles

Controls

Presets

Link 1 length

Link 2 length

Elbow-up solution

Inverse kinematics is the hard direction: given where you want the tip, find the joint angles. For a 2-link arm the law of cosines gives a clean closed form — but with two solutions (elbow-up or elbow-down) and none at all when the target is out of reach. Drag the target, or click anywhere to move it there.

▶ Run in Python

Data Inspector

Joint 1-20.8°

Joint 291.4°

Target dist126

Total reach180

Reachableyes

Governing equation

θ_{2} = arccos \frac{x ^{2} + y ^{2} - 10 0 ^{2} - 8 0 ^{2}}{2 \cdot 100 \cdot 80} = 91. 4^{\circ}, θ_{1} = atan2 (40, 120) - atan2 (80 sin θ_{2}, 100 + 80 cos θ_{2}) = - 20. 8^{\circ}

Reading this result: This 2-link arm (segments 100 and 80, total reach 180) has a closed-form inverse: the law of cosines gives the joint angles that place the tip exactly on the target, with two branches — elbow-up and elbow-down. Iterative methods like CCD or the Jacobian transpose converge to one of them.

Runs locally in your browser — free forever. Scale to the cloud when reality gets heavy.

or unlock everything with Pro →

Also for:Researchers Educators Engineers Hobbyists & Makers K-12 Students First Responders General version →

More with Inverse Kinematics

Inverse Kinematics for a robot arm Inverse Kinematics for a self-driving car Inverse Kinematics for a warehouse robot Inverse Kinematics for a drone delivery Inverse Kinematics for a walking robot Inverse Kinematics for a robotic gripper Inverse Kinematics for a CNC toolpath Inverse Kinematics for a line-follower

Frequently asked questions

Is this good for students?: Yes — this version of "Inverse Kinematics for a quadruped" is framed for students learning it for a class or exam. See the concept move instead of memorizing formulas — and check your homework intuition.
Do I need to install anything?: No. It runs in any modern browser, free, with no account required.