Design, Experimental Validation, and Pressure-Control Simulation of a Modular Pneumatic Soft-Finger Gripper

Abstract

Pneumatic soft grippers adapt to uncertain object geometry through compliant deformation, and their performance is governed by chamber geometry, material behavior, pneumatic routing, and pressure control. This study develops a modular soft-finger gripper and a common-pressure-control platform. A toothed, multi-chamber Shore A20 silicone finger was cast in split polylactic acid (PLA) molds. Uniaxial tensile data from the same material batch were fitted with a third-order Yeoh model and used in an Abaqus/Standard simulation with 25,940 10-node quadratic hybrid tetrahedral (C3D10H) elements. Across 5–40 kPa, measured chord angles agreed with finite-element predictions with a maximum relative error of 5.69%. A single finger generated a tip contact force of 0.96 N at 35 kPa. The H-shaped and X-shaped configurations were documented in qualitative object-grasping demonstrations on representative household objects, including regular, cylindrical, and small asymmetric forms. The physical platform integrates an Arduino UNO, metal–oxide–semiconductor (MOS) driver, 24 V pump, FA2021B three-way valve, M1 pressure manifold, and MATLAB App Designer host interface. Fixed-gain proportional–integral–derivative (PID) and fuzzy gain-scheduled PID controllers were compared only in nonlinear pressure-tracking simulations; no experimental closed-loop pressure-tracking results are reported. Fuzzy gain-scheduled PID reduced settling time from 13.12 to 6.62 s and integral absolute error (IAE) from 76.01 to 58.48 kPa s. The resulting framework combines modular design, material characterization, numerical validation, experimental grasping evidence, platform integration, and pressure-control simulation.