Soft Grippers

Definitional Boundaries & Taxonomy

Soft grippers represent a paradigm shift in robotic prehension, moving away from rigid-body kinematics toward continuously deformable materials. Defined by their intrinsic mechanical compliance, soft grippers exploit the hyperelastic properties of elastomers, responsive polymers, and fluidic networks to adaptively conform to geometrically complex, fragile, or highly variable target objects. Unlike traditional parallel-jaw or multi-fingered rigid end-effectors that rely on exact pose estimation and intense computational models to avoid crushing an object, soft grippers leverage "embodied intelligence" (morphological computation). Here, the material itself absorbs localization errors and geometric uncertainties. The taxonomy of soft grippers is primarily divided by actuation mechanisms:

1. Fluidic Elastomer Actuators (FEAs): Utilizing pneumatic or hydraulic pressure to induce bending, extending, or twisting through anisotropic structural designs (e.g., PneuNets).
2. Granular Jamming Grippers: Exploiting the reversible phase transition of granular materials within a flexible membrane from a fluid-like to a solid-like state via vacuum pressure.
3. Electroactive Polymers (EAPs) & Dielectric Elastomer Actuators (DEAs): Relying on high-voltage electric fields to induce Maxwell stresses that deform a dielectric membrane.
4. Tendon-driven Continuum Grippers: Using cables routed through soft matrices to achieve hyper-redundant continuous bending.
5. Thermal/Magnetic Responsive Grippers: Utilizing Shape Memory Alloys (SMAs) or magnetic micro-particles embedded in elastomeric matrices for specialized micro-manipulation.