Novel sensory-motor coupling in soft robotic systems

Lead Research Organisation: University of Bristol
Department Name: Mechanical Engineering

Abstract

The use of soft, flexible technologies in robotic systems is a fundamental shift from the traditional basis of how a robot should be designed. Compliant, deformable materials allow many biological principles to be emulated and this emerging soft approach can create robots that robustly deal with uncertainty, interact more safely with humans and compliantly move through unstructured environments.
The inherent compliance in soft robotic systems can be exploited to devolve computation away from the central high-level processor. This approach takes inspiration from nature, where organisms such as octopuses reduce computational demands on their brain by embodying intelligence into their tentacles. Biological species achieve such advanced behaviour through carefully tuned morphological parameters and a high integration of muscle and sensory elements.
This PhD will investigate how a soft robotic system's artificial muscles can be integrated with local sensory receptors to enable low-level computation through proprioceptive and environmental interaction. Inspired by nature, where sensory neurons often synapse in the spinal cord rather than the brain, novel technologies will be developed to enable dynamic low-level responses. This approach will be expanded by considering how different sensory modes can be exploited to create synaptic pathways to actuation.
Devolving computation to distributed sensory-motor elements in soft robots will lead to advances in the dynamic responsiveness of multiple degree-of-freedom systems and concomitant reductions in the computational loading of the central processor. Decentralising the control of the artificial muscles in soft robots will also improve their robustness to uncertainty as emergent behaviours can arise from localised sensory-motor interactions. It is envisaged that this PhD will make contributions towards the next generation of soft robotic system that can generate dynamic, multi-functional behaviours in a safe and efficient manner.

Publications

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Chen H (2019) RUBIC: An Untethered Soft Robot With Discrete Path Following in Frontiers in Robotics and AI

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Partridge A (2020) Passive, Reflex Response Units for Reactive Soft Robotic Systems in IEEE Robotics and Automation Letters

Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509619/1 01/10/2016 30/09/2021
1942482 Studentship EP/N509619/1 16/10/2017 15/05/2021 Alix Partridge
EP/R51245X/1 01/10/2017 30/09/2021
1942482 Studentship EP/R51245X/1 16/10/2017 15/05/2021 Alix Partridge
 
Description Three scientific papers have been generated from the ongoing research. URLs to these papers will be provided below.

The first paper was published in Frontiers of Robotics and AI and concerns the use of soft elastomer actuators (ballooning silicone structures) to actuate a cubic robot that is stable on all faces. Such a robotic platform can be used in disaster zones to create temporary network infrastructure or as a foundation for larger structures. https://www.frontiersin.org/articles/10.3389/frobt.2019.00052/full

The second paper was published as conference proceedings for the 2019 Robosoft conference in Seoul, South Korea. The paper concerns the use of buckling elements to create a binary trigger in soft elastomer pneumatic network structures (ballooning silicone structures that curl when inflated). The buckling elements act as high pass filters (only actuating at high pressures) for pressure and result in quick, twitch like responses. The research contributes to making more responsive soft robotic systems. https://ieeexplore.ieee.org/document/8722820

The third paper is under review for IEEE RA-L and has been accepted as conference proceedings for the 2020 Robosoft conference in Yale, United States of America. The paper concerns creating reservoirs of pressure around the body of a soft robot that vent into actuators when stimulated by the environment. In this way, it is possible to create reflex responses for soft robots that bypass the need for high level control. In essence, the robot has stores of high pressure within its body that can be triggered to make the robot respond to its environment.

This is preliminary work and will be investigated further over the remainder of the project.
Exploitation Route This research aims to assist in the creation of more reactive soft robotic systems that bypass central processing units . At present, soft robotic systems are often tethered to larger systems in order to achieve quick actuation. By utilising the technologies developed within this project, we hope that others may be able to realise quick actuation without the need for external systems, nor high level control. We believe that the design space for this project is very wide and could find applications in a variety of fields. We will continue to research applications of this work.
Sectors Other

URL https://www.frontiersin.org/articles/10.3389/frobt.2019.00052/full