Soft Robotics

Soft Robotics: Artificial Muscles and Artificial Organisms

Robots have traditionally been made from hard materials such as metal and plastic. They have been driven by motors and other heavy electro-mechanical actuators. These robots are more like machines than biological organisms.

Soft robotics on the other hand seeks to make robots that are soft, flexible and compliant, just like biological organisms. The ‘body’ of a soft robot is soft like natural tissue. A soft robot is driven not by heavy motors but by soft artificial muscles. The energy store in a soft robot much more closely resembles a biological ‘stomach’ than a conventional electrical battery. Sensors and transducers in a soft robot exploit the softness of the body, enabling new sensing modalities that mimic biological sensor systems. A soft robot is much more like an artificial organism than a machine.

An example of a soft robot is an artificial octopus which searches for victims under collapsed buildings following an earthquake. The robot can deform itself to squeeze into small gaps and ‘worm’ itself into the structure. When it finds a casualty trapped in the debris it can exert localised forces to create an air pocket.

Soft robotics is a major research theme at BRL that also draws upon research in a wide range of complimentary fields. For example:

Applications include artificial autonomous organisms that are self-sufficient and self-repairing, soft rescue robots, robots that interact with humans, medical robotics and devices, morphing materials and structures for engineering.

Soft Robotics team:

One aim of this project is to develop ‘artificial muscles’ for robots using dielectric elastomer actuators. These actuators are made from soft polymers coated with compliant electrodes and are actuated by placing a voltage across the electrodes. Soft structures can achieve complex movements and are more adaptable than traditional rigid arrangements.

Another benefit of these actuators is their use of energy. Although operated at high voltages the current they use is very small, resulting in low energy consumption. Energy efficiency is a large obstacle in the path to developing robots that can achieve everything we would like of them. Therefore this project additionally seeks to improve actuator efficiency by employing charge recovery. The basic idea is to recycle the energy from one actuator by transferring it to another and using it again. This should help make dielectric elastomers even more attractive when it comes to energy efficiency.

This project also has links with the Ecobot project. The low energy technologies go hand in hand, as conventional actuators would drain a large amount of the generated energy. We are hoping to develop actuated structures such as fluid delivery tubes, pumps and fuel cells that could be used on board the robot as part of its digestive system.

Ionic polymer metal composites are electro-active polymer actuators, or artificial muscles, which bend in response to a low voltage stimulus. This project is investigating the fabrication and exploitation of these composite materials as bio-mimetic swimming robots and as locomotion and water transport mechanisms. These robotic structures range in size from 10s of cm to under 10s of micrometers.