A simple sponge has improved the perception of robots, researchers at the University of Bristol have found.
This easy-to-make sponge plug device can help tough robots handle delicate objects with care, mimicking a human’s nuanced touch or variable stiffness.
The robots can jump, jump, and somersault, but they’re too stiff to catch the egg easily. Variable stiffness devices are potential solutions for contact compliance with rigid robots to reduce damage or improve the payload of soft robots.
This study, published at the IEEE International Conference on Robotics and Automation (ICRA) 2023, shows that variable stiffness can be achieved using a silicone sponge.
Lead author Tianqi Yue, from Bristol’s Department of Engineering Mathematics, explained: “Stiffness, also known as softness, is important in contact scenarios.
“Robot arms are too stiff, so they can’t have a human-like soft grip on delicate objects like an egg.
“What’s different about human robotic hands is that we have soft tissues surrounding the hard bones that act as a natural cushioning mechanism.
“In this paper, we succeeded in developing a soft device with variable stiffness to be placed on the tip of a robot to make robot-object contact safe.”
Silicone sponge is a cheap and easy to make material. It is a porous elastomer like a cleaning sponge used in everyday tasks.
By compressing the sponge, the sponge hardens, due to which it can be transformed into a variable stiffness device.
This device can be used in industrial robots in scenarios such as handling jellies, eggs and other fragile materials. It can also be used in service robots to make human-robot interactions safer.
“We were able to use a sponge to make a cheap and fast yet effective device that can help robots achieve soft contact with objects. Great potential comes from its low cost and light weight.”
“We believe that this silicone sponge-based variable stiffness device will provide a new solution in industry and healthcare, such as the requirement for adjustable stiffness in robotic polishing and ultrasound imaging.”
The team will now try to achieve variable stiffness in the device in several directions, including rotation.