Soft Robotic Actuator & Sensor

Fiber-Reinforced Elastomeric Enclosures (FREEs), a subset of pneumatic soft actuators with an asymmetric continuously deformable skin that are able to generate a wide range of deformations and forces, are utilized for modeling and measuring in all my work.

FREE's state without (left) and with (right) pressurized air*

Soft Robotic Actuator and Sensor

1. Modeling and Design of “Smart Braid” Inductance Sensors for Fiber-Reinforced Elastomeric Enclosures

“Smart Braid”, proposed by Prof. David Remy in 2014, is an effective way to estimate the motion of McKibben Muscle, a special case of FREEs with exactly symmetric structure. This work has never been extended to general FREEs.

This work mainly focused on two parts: (1) Extended the concept of Smart Braids to the broader class of two-fiber-family cylindrical FREEs and developed a dimensionless normalized model for the inductance measurement; (2) Validated the normalized model numerically and experimentally.

This work has been written as a journal paper and submitted to IEEE Sensors Journal.

Felt, Wyatt, Shihan Lu, and C. David Remy. "Modeling and Design of “Smart Braid” Inductance Sensors for Fiber-Reinforced Elastomeric Enclosures." IEEE Sensors Journal. Manuscript submitted for publication.

a. Normalized Model for Inductance Sensing and Numerical Validation

Presentation1.pptx

Dimensionless Normalized Function for Inductance Measure

b. Experimental Validation

Fabrication in progress for eta=1 smart braid

Fabrication done for eta=1 smart braid

Measurements for eta=1 smart braid

Physical Prototypes

Experimental validation results

Demo of Inductance Sensor for FREEs and Bellow

2. Modeling for Torsional and Axial Loads on Fluid-Driven Soft Robots

For soft robotics, to obtain accurate and efficient models that capture both the kinematic behavior and inherent non-linearity is essential to further control and estimation problems.

We developed a constitute model that connects FREE's behaviors with axial and torsional loading. This model considers several factors, including energy, strain, stress, internal pressure, and external axial and torsional loading.

Experimental data for a variety of kinematic behaviors has also been collected and analyzed, which shows consistence between the torque predicted by models and the torque captured by experiments.

Position-based testbed

FREE's bulking observed in experiments

Experimental validation results

Note: * means that picture is adapted from previous work in CSDL and RAMLab.

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