Companion to the Hugging Face Robotics Course · Unit 2

Arm Playground

Robot kinematics and control on the course's two-joint arm. Task space shows where the hand is. Configuration space maps every pair of joint angles (θ₁, θ₂) as one pixel. Follow the lesson on each tab, or just play.

Task space · where the hand is

Configuration space · (θ₁, θ₂)

free hits floor hits shelf past elbow limit hover = preview · click = go there

Lesson ·

More experiments for free play

    The math, live

    Discrete-time error: ek+1 = ek − kpΔt · ek−d (d = latency in ticks), starting from a unit step

    Controls


    Drag in the task pane to move the green target.

    Iterative IK starts from the current pose and steps downhill on ‖p(q) − p*‖² using the damped Jacobian. It ignores obstacles, just like a bare solver.

    Drag in the task pane to set the desired hand velocity ṗ* (green arrow).

    Teleop: hold the pad or ←↑→↓ / WASD to drive the hand. Diff-IK converts each command into joint speeds.

    Tracking error |Δp| over the last 10 s. Grey dashed curve = the ideal continuous response D·e−kpt after each step; the gap between it and the red line is what discrete updates, latency and the speed limit cost you.