Continuously bending reconfigurable robot manipulators for flexible handling and assembly in confined and remote environments

Lead Research Organisation: Imperial College London
Department Name: Design Engineering

Abstract

The majority of serial robots use traditional rigid-link designs with multiple joints and links [1]. However, for multiple individual tasks that are performed by these robots in reduced spaces, a lower number of degrees of freedom (DOF) is sufficient [2]. This includes activities such as manufacturing electronics and offshore operations, where working inside reduced spaces and in remote locations is vital. Other examples of such situations are deep sea, hazardous material handling, and space robotics. Whilst sufficient for the task, a low DOF limits the workspace, and therefore the flexibility of the system, hindering the ability for the robot to adapt to various tasks. For work within remote areas that requires complex positioning, a traditional robot arm with higher DOF seems more appropriate for instance, as a higher DOF allows the robot arm to adapt to given scenarios, accomplishing a larger range of complex tasks provided. Nevertheless, a higher number of DOF causes the robot to be larger, heavier, and sometimes more complex than necessary for particular activities. This can cause specific limitations when robotic requirements are needed to be met, for example weight limitations with space robotics. The ideal solution to this problem therefore is a simpler, low DOF robot that maintains the flexibility of the system.
Soft robot arms, implemented usually using a single continuously bending link, promise a number of improvements over stiff, discrete manipulators such as reduced size and weight requirements with an increase in system flexibility; however, these robotic systems have been struggling to achieve the holding strength and precision of fully rigid designs [3]. Recent research has explored the use of variable stiffness links in soft, continuum robots for surgery, which contains aspects of both systems by varying the rigidity of the robot [4][5]. This development allows the robot to overcome the strength limitation of soft robotics, by providing a rigid platform when the robot is 'activated'. However, at present, no robots with a reduced number of DOF that can be adaptable to multiple tasks with variable but controllable workspace exist; these robots are a need for the automation of processes and the augmentation of human operator capabilities in confined and remote environments.
This research aims to combine, improve, and extend existing research in soft robotics for use in reconfigurable serial arms, producing robots with a reduced number of DOF that can adjust their topology using variable stiffness links, thus being able to perform a range of tasks with a focus on handling and pickand-place assembly operations. Ideal implementations of these systems would be as collaborative robotics in operations that require a reduced size/weight robot with a high DOF performance, namely deep sea and space robotics. These novel manipulators have the possibility of greater flexibility by adapting to different workspaces while keeping the benefits of a lower DOF robotic system, such as weight, size, and control complexity. The proposed robots will be fabricated using serial chains of extrinsic malleable links: A variable stiffness, flexible, continuously bending link which can be repositioned by hand when in a non-rigid state, while holding its position when activated. These malleable links will be connected by revolute joints to be able to perform the operations that can be carried out with traditional robotic arms.

Publications

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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/N509486/1 01/10/2016 30/09/2021
2286512 Studentship EP/N509486/1 30/09/2017 31/07/2021 Angus Clark