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Title: Dynamics and control of discrete hyper-redundant manipulators
Author: Foster, Darius John
ISNI:       0000 0004 2739 1902
Awarding Body: University of Bristol
Current Institution: University of Bristol
Date of Award: 2011
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Robotic manipulators have for years been used in place of humans where tasks are too dangerous, arduous or repetitive. Thanks to their extra degrees-of-freedom hyper- redundant manipulators offer an increased ability to move within physically constrained spaces; useful for inspection and maintenance operations in hard-to- access environments. However, being comprised of many links joined end-to-end, they usually exhibit complex behaviour, and as a result are difficult to model and implement in the real-world. Indeed, very few examples have been successfully deployed. This thesis considers the kinematics, dynamics, and control of these hyper- redundant manipulators. A form of inverse kinematics based on a Bezier curve was developed. The method reduced the complexity of the problem and removed the need to use Jacobian matrices. It compared well to other inverse kinematics methods, and also proved to be implementable on a real-world test-rig. The standard approach to controlling hyper-redundant manipulators imposes constraints on the mechanical design of hyper-redundant manipulators. Proportional- integral-derivative control necessitates the use of highly geared joints, and usually exacerbate problems with backlash. This thesis investigated the application of nonlinear controllers to hyper-redundant manipulators. Sliding mode control was shown to be superior, particularly in response to gravitational loads. Chattering was successfully suppressed via incorporation of a modified error-dependent switching gain - the control effort was reduced by 95%. These ideas were validated in preliminary tests on a real-world test-rig.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available