Developing Flexible Soft Robotic Arms for Enhanced Object Manipulation and Accessibility

Researchers in Robotics Engineering at Worcester Polytechnic Institute (WPI) are developing a compact, flexible robotic arm inspired by origami. The device is designed to assist wheelchair users in safely grasping, lifting, and carrying objects beyond their reach.

Researchers Cagdas Onal, Berk Calli, and Loris Fichera are developing a framework for the design, modeling, and control of soft continuum robotic arms, which offer greater flexibility than conventional robotic arms. The four-year project is supported by a $1,314,792 grant from the National Science Foundation (NSF).

The basic scientific discoveries we are making in this research address real-world challenges for people who use wheelchairs and need devices that will help them grab out-of-reach objects. A new class of lightweight, safe robotic arms based on the breakthroughs we are making would give those individuals more independence in their daily activities.

Cagdas Onal, Principal Investigator and Associate Professor, Department of Robotics Engineering, Worcester Polytechnic Institute

Soft continuum robotic arms can expand, contract, and bend along their length, allowing movement in multiple directions and around obstacles, similar to a coiled spring. Their adaptability makes soft robotics suitable for complex human environments. However, compared to conventional robotic arms made from rigid materials, soft robotic arms typically have lower strength, stability, and precision.

To address these limitations, the researchers are designing origami-inspired structures and developing fabrication techniques using lightweight plastics, 3D-printed components, and commercially available materials such as cables and sensors.

By folding flat plastic sheets into spring-like tube structures, the team is creating modular robotic components that are lightweight, rigid, and resistant to twisting. At the same time, they are developing algorithms for microcontroller platforms to regulate the robotic arm’s movements and responses.

This project builds on Onal's previous research on user-friendly soft robotic systems designed for tasks that rigid robots cannot perform. Calli, an Associate Professor of Robotics Engineering, contributes expertise in object manipulation technologies, particularly for robots used in recycling centers. Fichera, an Assistant Professor of Robotics Engineering, specializes in surgical robot development.

Soft robots have big potential for assistive robotics. You would need a very large, rigid robot to reach the high shelves of a cabinet, for example, and installing such robots next to a user does not make sense. Soft robots could expand to reach objects and shrink to a compact size when not in use, and they would be safer for users than rigid robots. Our project will enable soft robotics for assistive uses by developing novel sensing, control, and AI technologies.

Berk Calli, Worcester Polytechnic Institute

One of the research objectives, according to Onal, is to develop a flexible, extendable robotic arm equipped with commercially available grippers capable of picking up and carrying a cup of water without spilling.

It is exciting to work with WPI colleagues and students on a project that is pushing the boundaries of this technology. More importantly, this research offers an opportunity to directly impact people in a positive way by enabling them to lift, move, and carry objects that they previously might not have been able to reach from a wheelchair. That would be a real achievement.

Cagdas Onal, Principal Investigator and Associate Professor, Department of Robotics Engineering, Worcester Polytechnic Institute

Cagdas Onal is leading fundamental research into robotic arms that are soft enough to stretch and bend but sturdy enough to safely carry a glass of water. The research could lead to a new class of assistive devices for wheelchair users. Video Credit: Worcester Polytechnic Institute