SPSouvik Poddar
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Arizona State University, USA · Soft Robotics · Ankle Prosthetics · Fabric-Based Actuation

Fabric-Based Soft Ankle Module to Mimic Human Ankle Stiffness

Affiliation: Arizona State University, USA

This project focused on the design and fabrication of a compliant fabric-based soft ankle module using inflatable actuator arrays to reproduce ankle stiffness behavior during walking.

Soft actuator arraysDesign & fabricationMechanical testingAnkle stiffness

Project overview

Human ankle stiffness plays an important role in shock absorption, propulsion, and stable walking. This project developed a fabric-based soft ankle module capable of generating plantarflexion and dorsiflexion torque using stacked inflatable actuator arrays.

The module was designed as a lightweight, compliant alternative for mimicking ankle stiffness. The architecture used a top plate, bottom plate, revolute joint, and antagonistic soft actuator arrays to generate torque about the ankle-like joint.

My contribution

  • Worked on the design and fabrication of the fabric-based soft ankle module.
  • Supported development of the soft inflatable actuator arrays used to generate plantarflexion and dorsiflexion torque.
  • Contributed to physical prototyping and integration of the actuator arrays with the ankle module structure.
  • Helped translate functional requirements such as compact size, range of motion, torque capacity, and mechanical behavior into a fabricated soft robotic module.

Objectives

  • Design a compliant fabric-based ankle module for plantarflexion and dorsiflexion.
  • Use inflatable actuator arrays to generate ankle-like torque and stiffness.
  • Keep the module lightweight and compact for lower-limb robotic applications.
  • Fabricate and integrate the actuator arrays with a mechanical ankle structure.
  • Evaluate torque output as a function of pressure and end-effector angle.

Results

  • The module was designed to target 50% of biological ankle torque during walking.
  • The soft ankle module achieved a wide range of motion in plantarflexion and dorsiflexion.
  • Torque characterization showed increasing torque output with increasing actuator pressure across multiple end-effector angles.
  • The fabric-based actuator array architecture demonstrated the feasibility of using soft pneumatic structures to mimic ankle stiffness.

Tools and methods

Fabric-based inflatable actuatorsSoft roboticsMechanical designFabricationPneumatic actuationActuator arraysAnkle biomechanicsTorque characterization

Technical focus

Soft robotic moduleWearable device designActuator integrationPressure-torque behaviorMechanical fabricationPrototype validationAnkle biomechanicsStiffness characterizationSystem integrationExperimental testing

Selected figures

Soft ankle module overview and end-effector rotation

Soft ankle module overview. The fabric-based soft ankle module uses actuator arrays arranged around an ankle-like structure to create end-effector rotation for plantarflexion and dorsiflexion.

Design and fabrication details of the fabric-based soft ankle module

Design and fabrication. The module combines a top plate, bottom plate, revolute joint, and stacked fabric-based inflatable actuator arrays to generate torque about the ankle joint axis.

Torque output with respect to pressure for the soft ankle module

Torque-pressure characterization. Experimental torque output increased with actuator pressure across different end-effector angles, supporting data-driven modeling of the soft ankle module.

These are your provided soft ankle module figures added directly to the portfolio project page.