Control of navigation and feeding actions of a continuum arm for in-situ repair

Palmer, David (2016) Control of navigation and feeding actions of a continuum arm for in-situ repair. PhD thesis, University of Nottingham.

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Maintenance and repair of large or complex structures is often an afterthought post-production. Conventional restoration techniques involve removing components and performing operation in a workshop. For many of these structures, it is not feasible. As such, an EU Project was setup to create a generic in-situ repair tool. This was comprised of two individual robots. This study follows the development of the control algorithms for one of the systems, devised as Snake Arm, which is a sub-set of the field of hyper-redundant manipulators. It consists of 12 sections, which means there are 25 degrees of freedom including the feed-in mechanism. The robot has been demonstrated for two main scenarios: the inspection and repair of a gas turbine engine whilst it is still attached to an aeroplane wing, and inspection of an RPV head inside a nuclear reactor while mounted on the other robot.

Through this work, two algorithms are created to overcome the challenges faced. Both are designed in a way that the kinematic and behaviour of the robot can be interchanged for different systems. To navigate the Snake Arm, an algorithm is required to manage the shape as the tip follows a path. The aim being to prevent deviation from this guided route while continuing the advancement. Previous work by others was specific to a particular design or relied on environmental data in their approach. This is combined with another algorithm to provide a feed-in movement by uncoiling the Snake Arm from a rotating drum. Not only does this require a smooth action to translate the pose from coiled to straight, but the handover point must remain on the expected trajectory for the navigation algorithm. No prior work was found on an active, three-dimensional uncoiling process.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Axinte, Dragos A.
Keywords: Gas-turbines, Maintenance and repair, Robots, Motion
Subjects: T Technology > TJ Mechanical engineering and machinery
Faculties/Schools: UK Campuses > Faculty of Engineering
Item ID: 33170
Depositing User: Palmer, David
Date Deposited: 01 Aug 2016 12:57
Last Modified: 26 Apr 2022 07:53

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