577 research outputs found
Teleoperation of MRI-Compatible Robots with Hybrid Actuation and Haptic Feedback
Image guided surgery (IGS), which has been developing fast recently, benefits significantly from the superior accuracy of robots and magnetic resonance imaging (MRI) which is a great soft tissue imaging modality. Teleoperation is especially desired in the MRI because of the highly constrained space inside the closed-bore MRI and the lack of haptic feedback with the fully autonomous robotic systems. It also very well maintains the human in the loop that significantly enhances safety. This dissertation describes the development of teleoperation approaches and implementation on an example system for MRI with details of different key components. The dissertation firstly describes the general teleoperation architecture with modular software and hardware components. The MRI-compatible robot controller, driving technology as well as the robot navigation and control software are introduced. As a crucial step to determine the robot location inside the MRI, two methods of registration and tracking are discussed. The first method utilizes the existing Z shaped fiducial frame design but with a newly developed multi-image registration method which has higher accuracy with a smaller fiducial frame. The second method is a new fiducial design with a cylindrical shaped frame which is especially suitable for registration and tracking for needles. Alongside, a single-image based algorithm is developed to not only reach higher accuracy but also run faster. In addition, performance enhanced fiducial frame is also studied by integrating self-resonant coils. A surgical master-slave teleoperation system for the application of percutaneous interventional procedures under continuous MRI guidance is presented. The slave robot is a piezoelectric-actuated needle insertion robot with fiber optic force sensor integrated. The master robot is a pneumatic-driven haptic device which not only controls the position of the slave robot, but also renders the force associated with needle placement interventions to the surgeon. Both of master and slave robots mechanical design, kinematics, force sensing and feedback technologies are discussed. Force and position tracking results of the master-slave robot are demonstrated to validate the tracking performance of the integrated system. MRI compatibility is evaluated extensively. Teleoperated needle steering is also demonstrated under live MR imaging. A control system of a clinical grade MRI-compatible parallel 4-DOF surgical manipulator for minimally invasive in-bore prostate percutaneous interventions through the patient’s perineum is discussed in the end. The proposed manipulator takes advantage of four sliders actuated by piezoelectric motors and incremental rotary encoders, which are compatible with the MRI environment. Two generations of optical limit switches are designed to provide better safety features for real clinical use. The performance of both generations of the limit switch is tested. MRI guided accuracy and MRI-compatibility of whole robotic system is also evaluated. Two clinical prostate biopsy cases have been conducted with this assistive robot
Medical robots for MRI guided diagnosis and therapy
Magnetic Resonance Imaging (MRI) provides the capability of imaging tissue with fine resolution and
superior soft tissue contrast, when compared with conventional ultrasound and CT imaging, which
makes it an important tool for clinicians to perform more accurate diagnosis and image guided therapy.
Medical robotic devices combining the high resolution anatomical images with real-time navigation, are
ideal for precise and repeatable interventions. Despite these advantages, the MR environment imposes
constraints on mechatronic devices operating within it. This thesis presents a study on the design and
development of robotic systems for particular MR interventions, in which the issue of testing the MR
compatibility of mechatronic components, actuation control, kinematics and workspace analysis, and
mechanical and electrical design of the robot have been investigated. Two types of robotic systems
have therefore been developed and evaluated along the above aspects.
(i) A device for MR guided transrectal prostate biopsy: The system was designed from components
which are proven to be MR compatible, actuated by pneumatic motors and ultrasonic motors, and
tracked by optical position sensors and ducial markers. Clinical trials have been performed with the
device on three patients, and the results reported have demonstrated its capability to perform needle
positioning under MR guidance, with a procedure time of around 40mins and with no compromised
image quality, which achieved our system speci cations.
(ii) Limb positioning devices to facilitate the magic angle effect for diagnosis of tendinous injuries:
Two systems were designed particularly for lower and upper limb positioning, which are actuated and
tracked by the similar methods as the first device. A group of volunteers were recruited to conduct
tests to verify the functionality of the systems. The results demonstrate the clear enhancement of the
image quality with an increase in signal intensity up to 24 times in the tendon tissue caused by the
magic angle effect, showing the feasibility of the proposed devices to be applied in clinical diagnosis
Robot Manipulators
Robot manipulators are developing more in the direction of industrial robots than of human workers. Recently, the applications of robot manipulators are spreading their focus, for example Da Vinci as a medical robot, ASIMO as a humanoid robot and so on. There are many research topics within the field of robot manipulators, e.g. motion planning, cooperation with a human, and fusion with external sensors like vision, haptic and force, etc. Moreover, these include both technical problems in the industry and theoretical problems in the academic fields. This book is a collection of papers presenting the latest research issues from around the world
Enabling technologies for MRI guided interventional procedures
This dissertation addresses topics related to developing interventional assistant devices
for Magnetic Resonance Imaging (MRI). MRI can provide high-quality 3D visualization
of target anatomy and surrounding tissue, but the benefits can not be readily harnessed for
interventional procedures due to difficulties associated with the use of high-field (1.5T or
greater) MRI. Discussed are potential solutions to the inability to use conventional mecha-
tronics and the confined physical space in the scanner bore.
This work describes the development of two apparently dissimilar systems that repre-
sent different approaches to the same surgical problem - coupling information and action
to perform percutaneous (through the skin) needle placement with MR imaging. The first
system addressed takes MR images and projects them along with a surgical plan directly
on the interventional site, thus providing in-situ imaging. With anatomical images and a
corresponding plan visible in the appropriate pose, the clinician can use this information to
perform the surgical action.
My primary research effort has focused on a robotic assistant system that overcomes
the difficulties inherent to MR-guided procedures, and promises safe and reliable intra-prostatic needle placement inside closed high-field MRI scanners. The robot is a servo
pneumatically operated automatic needle guide, and effectively guides needles under real-
time MR imaging. This thesis describes development of the robotic system including
requirements, workspace analysis, mechanism design and optimization, and evaluation of
MR compatibility. Further, a generally applicable MR-compatible robot controller is de-
veloped, the pneumatic control system is implemented and evaluated, and the system is
deployed in pre-clinical trials. The dissertation concludes with future work and lessons
learned from this endeavor
Non-linear actuators and simulation tools for rehabilitation devices
Mención Internacional en el título de doctorRehabilitation robotics is a field of research that investigates the applications of
robotics in motor function therapy for recovering the motor control and motor capability.
In general, this type of rehabilitation has been found effective in therapy for
persons suffering motor disorders, especially due to stroke or spinal cord injuries. This
type of devices generally are well tolerated by the patients also being a motivation in
rehabilitation therapy. In the last years the rehabilitation robotics has become more
popular, capturing the attention at various research centers. They focused on the development
more effective devices in rehabilitation therapy, with a higher acceptance
factor of patients tacking into account: the financial cost, weight and comfort of the
device.
Among the rehabilitation devices, an important category is represented by the
rehabilitation exoskeletons, which in addition to the human skeletons help to protect
and support the external human body. This became more popular between the
rehabilitation devices due to the easily adapting with the dynamics of human body,
possibility to use them such as wearable devices and low weight and dimensions which
permit easy transportation.
Nowadays, in the development of any robotic device the simulation tools play an
important role due to their capacity to analyse the expected performance of the system
designed prior to manufacture. In the development of the rehabilitation devices,
the biomechanical software which is capable to simulate the behaviour interaction
between the human body and the robotics devices, play an important role. This
helps to choose suitable actuators for the rehabilitation device, to evaluate possible
mechanical designs, and to analyse the necessary controls algorithms before being
tested in real systems.
This thesis presents a research proposing an alternative solution for the current
systems of actuation on the exoskeletons for robotic rehabilitation. The proposed
solution, has a direct impact, improving issues like device weight, noise, fabrication
costs, size an patient comfort. In order to reach the desired results, a biomechanical software based on Biomechanics of Bodies (BoB) simulator where the behaviour of
the human body and the rehabilitation device with his actuators can be analysed,
was developed.
In the context of the main objective of this research, a series of actuators have
been analysed, including solutions between the non-linear actuation systems. Between
these systems, two solutions have been analysed in detail: ultrasonic motors
and Shape Memory Alloy material. Due to the force - weight characteristics of each
device (in simulation with the human body), the Shape Memory Alloy material was
chosen as principal actuator candidate for rehabilitation devices.
The proposed control algorithm for the actuators based on Shape Memory Alloy,
was tested over various configurations of actuators design and analysed in terms of energy
eficiency, cooling deformation and movement. For the bioinspirated movements,
such as the muscular group's biceps-triceps, a control algorithm capable to control
two Shape Memory Alloy based actuators in antagonistic movement, has been developed.
A segmented exoskeleton based on Shape Memory Alloy actuators for the upper
limb evaluation and rehabilitation therapy was proposed to demosntrate the eligibility
of the actuation system. This is divided in individual rehabilitation devices for
the shoulder, elbow and wrist. The results of this research was tested and validated
in the real elbow exoskeleton with two degrees of freedom developed during this thesis.Programa Oficial de Doctorado en Ingeniería Eléctrica, Electrónica y AutomáticaPresidente: Eduardo Rocón de Lima.- Secretario: Concepción Alicia Monje Micharet.- Vocal: Martin Stoele
Modeling & Analysis of Design Parameters for Portable Hand Orthoses to Assist Upper Motor Neuron Syndrome Impairments and Prototype Design
Wearable assistive robotics have the potential to address an unmet medical need of reducing disability in individuals with chronic hand impairments due to neurological trauma. Despite myriad prior works, few patients have seen the benefits of such devices. Following application experience with tendon-actuated soft robotic gloves and a collaborator\u27s orthosis with novel flat-spring actuators, we identified two common assumptions regarding hand orthosis design. The first was reliance on incomplete studies of grasping forces during activities of daily living as a basis for design criteria, leading to poor optimization. The second was a neglect of increases in muscle tone following neurological trauma, rendering most devices non-applicable to a large subset of the population. To address these gaps, we measured joint torques during activities of daily living with able-bodied subjects using dexterity representative of orthosis-aided motion. Next, we measured assistive torques needed to extend the fingers of individuals with increased flexor tone following TBI. Finally, we applied this knowledge to design a cable actuated orthosis for assisting finger extension, providing a basis for future work focused on an under-represented subgroup of patients
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