FLEXIBLE-CONTINUUM ROBOT FOR BLADDER TISSUE DIAGNOSTICS
Abstract
The aim of this thesis is to investigate and develop a robotic system capable of a transurethral
palpation of any targeted area on the bladder interior wall tissue to determine the biomechanical properties of the tissue considering the urinary tract geometric constraints and to
demonstrate the motion kinematics of such robot to achieve a desired robot pose normal to
any localized region throughout the bladder workspace.
Current technologies have, to varied degree of success, provide approximate, global diagnostics information to bladder tissue elasticity. However, no direct access qualitative methods
to measure the bladder tissue properties are known. For this reason, a survey of robotic
systems applied to minimally invasive surgery was performed with the aim of repurposing
existing robotic systems for bladder elasticity dysfunction diagnostics. The result demonstrated their limitations and a requirement for a procedure specific solution.
In the first part, this thesis examines the advantages of
flexible robotic manipulators over
rigid link robotic manipulators; and the design, actuation and modeling principles of
flexible
robotic manipulators; the relationship between bladder tissue elasticity and the health condition of a patient. In the subsequent parts, a conceptualized design of the robotic system which
comprised of a
flexible-continuum module, a rigid tube and tendon actuation mechanism,
and a hyper-spherical actuation base was proposed. Furthermore, the Modified Denavit-
Hartenberg parameter approach was applied to obtain the robot forward kinematics motion
while a close-loop inverse differential kinematics that makes use of a Jacobian relationship
between the joint space and the cartesian space to obtain a desired robot pose. Consequently,
mechanical stress analyses of the structural components of the
flexible-continuum module are
provided to determine the fabrication material(s) using FDA approved standards. Finally,
structural components of the
flexible-continuum module were prototyped using 3D printing
technologies to visualize the proposed robot and its function.
The results show a proposed robot capable of reaching a desired pose at any targeted location
normal to the bladder surface with observable position and orientation errors, throughout
the bladder workspace. Also, the evaluation of the
flexible-continuum module proves the
functionality of coupling rigid-
flexible components to obtain structural stiffness while also
maintaining dexterity.