Continuum manipulators have historically been considered serial devices, perhaps because they typically have a long slender form, and the dominant geometric modeling paradigm is constant curvature arc segments tangentially connected in series. However, as some researchers have noted, many continuum designs also contain aspects resembling parallel architectures. For example, multiple entities are often constrained and connected in parallel within a single arc segment to achieve 2-DOF bending actuation (e.g. pneumatic muscles multi-backbone designs multiple embedded tendons and concentric precurved tubes. In my thesis, I seek to explore the 6-RUS Parallel Continuum Robot (PCR) which consists of passive flexible link connected to the end-effector through spherical joint and connected to rigid part through an universal joint.
The goal of the thesis is to develop a Cosserat rod theory based Kinetostatic modelling framework for 6-RUS PCR. The state differential equations is to be solved for each flexible leg which tracks their deformation independently. Also boundary conditions (BC) must be defined at both the end-effector and the base position which provides the formulation of the physical constraints that is inherent to the closed loop robot structure. Meeting these conditions creates a boundary value problem (BVP). This BVP can be solved using a shooting method which iteratively solves the independent sets of equations for each leg along with their coupled BC. This process should eventually result in a visualising the response of the end-effector pose to external forces. The validity of the proposed kinetostatic model will be assessed through the implementation of kinetostatic model-based control.
In conclusion, this thesis proposal aims to address the fundamental challenges in the kinetostatic modeling of a 6 RUS parallel continuum robot using the cosserat rod theory coupled with rigid bodies. By leveraging the unique capabilities of this theory, I anticipate to uncover new insights into the behavior and performance of such robots.