- Contact Sensing
- Structural Dynamics
- Tactile Display
- Friction Analysis
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| Research Topics | ||||
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Robotics - Contact Sensing - Structural Dynamics - Tactile Display - Friction Analysis |
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| Medical Robotics | |
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| Optimal
Port Placement for Minimally Invasive Surgery |
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| Graphical Displays for
Image Guided Surgery Over the past few years, several important applications for laparoscopic ultrasound (lapUS) have emerged, such as improved staging of hepatic and pancreatic malignancies. Despite these advances, surgeons have been slow to adopt lapUS. The major obstacle facing surgeons learning to us lapUS is understanding how the ultrasound images are oriented relative to the patient. The basis of this problem is that the orientation techniques used by transabdominal ultrasonographers are difficult to apply with laparoscopic instruments. This project developed a system which provides orientation information by rendering the lapUS image plane relative to an aortagram in real time. This display is helpful because it provides physicians with important spatial cues that ultimately improve their ability to interpret the ultrasound images. In the system validation trials, physicians identified more landmarks correctly using the navigation system (69% vs. 25%, p=0.02). |
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3D Ultrasound Guided Intracardiac Surgery Many investigators now recognize that cardiopulmonary bypass (CPB) poses
significant risks to the patient. Furthermore, during reconstructive surgical
procedures inside the heart, with the use of CPB and cardiac arrest, a
repair is done inside a relaxed heart which can be easily distorted with
surgical retractors. This makes evaluation of the current geometry relative
to the reconstructive ideal quite challenging, particularly for mitral
valve surgery. Recognition of these problems with traditional intracardiac
surgical approaches involving CPB have motivated us to develop image-guided
surgical techniques for safe and accurate intracardiac procedures without
CPB using real time 3-D ultrasound for image guidance. For this development
effort, we have focused on two of the most common intracardiac surgical
procedures: atrial septal defect closure in children and mitral valve
annuloplasty for annular dilatation in adults. |
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Acoustic Diffuser for Use in Medical Instruments Ultrasound images of medical instruments are blurred and unclear due
to strong specular reflections from the metallic surfaces of the instruments,
limiting the usefulness of ultrasound in applications where precision
is necessary (e.g. surgery). The goal of our research is to reduce these
specular reflections. The approach is to adapt the concept of an acoustic
diffuser, first proposed by Manfred Schroeder in 1975 for concert halls,
to an ultrasound application. Since manufacturing a diffuser which scatters
high-frequency acoustic waves is expensive and impractical on a large
scale, scattering properties of other surface geometries are being investigated.. |
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Robot Assisted Fetal Heart Surgery Often times it is necessary to intervene early in the development of a fetus to correct sever cardiac malformations. New transuterine minimally invasive procedures are being developed to correct these abnormalities in the 2nd and 3rd trimester of pregnancy. Topics of this research include automating portions of the surgical procedure as well as providing control and guidance using real time 3-D ultrasound with robotic manipulators for increased precision, reproducibility, safety, and speed of the surgical tasks |
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| Atrial Biomechanics Because of its location relative to the chest wall and the relative lack of motion (as compared to the other chambers of the heart) the Right Atrium (RA) is thought to be an optimal location for port entry in tele-robotic heart valve repair. While the RA is of minimal importance as a mechanical pump, the electrical signals which stimulate the contractions in the heart pass through the RA. This project is exploring the effect of port insertion and movement on tissue viability. Areas studied include fiber alignment, stress/strain relationships, and signal propagation. |
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| Contact Sensing | |
| Modeling
by Manipulation At present, teleoperation is the only way that robots can perform sophisticated manipulation tasks in unstructured environments. In this control mode, the human operator performs all required sensing and planning, and generates all motion commands based on feedback from the remote environment. In practical teleoperation systems (e.g. undersea operations, tele-surgery, etc ), the sensory feedback is often limited to video images without force feedback, which greatly restricts dexterity and productivity. We have been working to alleviate this situation by using information from the remote robot arm's sensors to assist in teleoperated manipulation tasks. We have derived algorithms that identify first order geometric properties such as dimensions and orientations. |
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| Contact State Distingusihability and Identifiability Autonomous manipulation tasks can be decomposed into sequences of contact
states modeled by algebraic equations relating the parameters of the objects
in contact to the robot sensors. Success of task execution relies on the
accurate estimation of the contact states. A rigorous approach to estimator
design involves ensuring that the proposed set of sensors and associated
contact state descriptions are sufficient (1) to distinguish each contact
state, and (2) for each contact state, to identify the objects’
physical parameters. |
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| Structural Dynamics | |
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Mechanical
Realization Before building main structures such as ship hulls and airplane fuselages on which equipments can survive, scaled mechanical models are often used to test structural design concepts. In this research, we want to study the design methods for mechanical emulators which preserve the driving-point behaviors of the active machineries (such as turbine generators, motors) and the passive equipments which are usually the most dynamically complex components in the dynamical system. For the passive equipment emulators, the following approaches will be used. First, by using model reduction methods, reduced-order models will be achieved based on modal analysis data. Second, the reduced-order models will be realized by different approaches such as optimization procedure, electrical network synthesis and state space techniques. For active mechanical emulators, shakers will be used to emulate the active components in the machineries. |
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MEMS
Filter High-Q Microelectromechanical (MEMS) resonators which are used for frequency selection can serve as on-chip replacements for off-chip crystal and SAW resonators. In this research, the concept of periodic structures has been used to design the MEMS resonators which have alternate stopbands and passbands. The dynamical responses of MEMS resonators are measured using Laser Doppler Vibrometer(LDV). Modal analysis and FEM techniques which have been widely used in macro mechanical structures are used to investigate dynamical properties of these MEMS resonators. |
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| Tactile Display | |
| Multichannel
Vibrotactile Display Augmenting perception in man-machine systems consists of two parts. First, machine sensor data must be interpreted in a way appropriate to the task. Second, the task-specific information must be communicated to the operator in a format that addresses the limitations of human sensory information processing. For example, during teleoperated surgery, vocal communication between non-operator team members can interfere with an auditory display. Similarly, overlaying visual displays with an endoscope view during surgery can be costly and non-intuitive due to scene complexity and the wide range of viewpoints encountered. Within this context, a multichannel vibrotactile device was designed, developed and tested for sensory substitution during teleoperation. |
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| Friction Analysis | |
Friction Modeling |
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