Soft Pneumatic Gripper vs. Rigid Jaw (2D)

Object to grasp

Gripper type

Air pressure 0%

Live status

—Adjust pressure or gap, then lift.

Grasp success — all combos

Object	Soft	Rigid
Sphere	—	—
Star	—	—
Wafer	—	—

How it works

The soft finger is a pressurized bellows: as internal pressure rises, curvature κ grows linearly and the whole limb bends along a constant-curvature arc x(t)=(1-cosθ)/κ, y(t)=sinθ/κ with θ=κt. Same law, every object — the finger just keeps curling until it meets resistance.

The rigid jaw has to be told exactly where to close. It only ever touches an object at two flat points, so the gap must match that object's width to a few percent: too wide and it slips through, too narrow and it jams a rigid object or crushes a fragile one.

Air pressure — same slider, same curling law, for every object. Above a threshold every shape gets wrapped and held.
Jaw gap — must be re-computed by hand for each object; the safe window is narrow, and there's no margin for the wafer.

Soft bellows finger Rigid jaw Crushed / dropped