Soft Pneumatic Gripper vs. Rigid Jaw

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

Each soft finger is a pressurized bellows: pumping air in expands the outer wall more than the (fibre-reinforced) inner wall, so the whole limb sweeps into a smooth constant-curvature arc — the same curve for every object, since the finger simply keeps curling until it meets resistance. No shape model, no planning.

The rigid gripper has to be told exactly where to close. Its two flat jaws only ever touch an object at two points, so the gap has to match that object's width to a few percent: too wide and it slips out under load, too narrow and it either can't close (rigid object) or crushes what's between the jaws (fragile object). An irregular shape rarely offers two parallel flat faces at all, so even a "correct" gap is unstable.

Air pressure — same slider, same curling law, for every object. Above a modest 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

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