Geometry-based pneumatic actuators for soft robotics

TL;DR

This paper introduces geometry-based pneumatic actuators (GPAs) that enable complex, predictable, and customizable deformation patterns in soft robotics, overcoming traditional design limitations.

Contribution

The paper presents a novel design approach for pneumatic actuators using constraint layers with CNC heat-sealed chambers, enabling multi-states, near-zero bending radii, and complex geometries.

Findings

Achieved predictable linear and nonlinear deformation behaviors.

Demonstrated applications in wearable robotics, haptic interfaces, and soft locomotion.

Reduced muscle activity and provided force feedback in prototypes.

Abstract

Soft pneumatic actuators enable safe human-machine interaction with lightweight and powerful applied parts. On the other side, they suffer design limitations as regards complex actuation patterns, including minimum bending radii, multi-states capabilities and structural stability. We present geometry-based pneumatic actuators (GPAs), a design and implementation approach that introduces constraint layers with configurable CNC heat-sealed chambers. The approach achieves predictable deformation, near-zero bending radii, multi-states actuation, and enables customizable and repeatable complex actuated geometries. Mathematical modeling reveals predictable linear angle transformations and validates nonlinear torque-angle relationships across diverse configurations. We demonstrate versatility of the GPAs approach through three applications: a 49 g wrist exoskeleton reducing muscle activity by up to 51%, a 30.8 g haptic interface delivering 8 N force feedback with fast response, and a 208 g bipedal robot achieving multi-gait locomotion. GPAs establish a configurable platform for next-generation wearable robotics, haptic systems, and soft locomotion devices.