Jake Abbott

• University of Utah

Therapeutic protocols involving subretinal injection, which hold the promise of saving or restoring sight, are challenging for surgeons because they are at the limits of human motor and perceptual abilities. Excessive or insufficient indentation of the injection cannula into the retina or motion of the cannula with respect to the retina can result...

A variety of robot-assisted surgical systems have been proposed to improve precision in the most challenging eye surgeries. However, little attention has been paid to patient motion due to breathing, snoring, talking, and other events that are common during eye surgery. This is problematic because patient motion is typically relative to a grounded...

A variety of robot-assisted surgical systems have been proposed to improve the precision of eye surgery. Evaluation of these systems has typically relied on benchtop experiments with artificial or enucleated eyes. However, this does not properly account for the types of head motion that are common among patients undergoing eye surgery, which a clin...

Hypothesis: The pose (i.e., position and orientation) of a guinea-pig cochlea can be accurately estimated using externally observable features, without requiring computed-tomography (CT) scans. Background: Guinea pigs are frequently used in otologic research as animal models of cochlear-implant surgery. In robot-assisted surgical insertion of co...

Hypothesis: Undesirable forces applied to the basilar membrane during surgical insertion of lateral-wall cochlear-implant electrode arrays (EAs) can be reduced via robotic insertion with magnetic steering of the EA tip. Background: Robotic insertion of magnetically steered lateral-wall EAs has been shown to reduce insertion forces in vitro and i...

Research is conducted into freeze‐casting of surface‐magnetized Fe3O4 particles under uniform, low‐strength magnetic fields (5.2 mT) to mimic the mechanical characteristics of natural human bone. Freeze‐casting is a technique that fabricates porous materials by directionally freezing and sublimating an aqueous slurry. A novel, Helmholtz coil‐based...

We consider sorting for the broad class of micromachines (also known as microswimmers, microrobots, micropropellers, etc.) propelled by rotating magnetic fields. We present a control policy that capitalizes on the variation in magnetic properties between otherwise-homogeneous micromachines to enable the sorting of a select fraction of a group from...

Magnetic guidance of cochlear-implant electrode arrays during insertion has been demonstrated in vitro to reduce insertion forces, which is believed to be correlated to a reduction in trauma. In those prior studies, the magnetic dipole-field source (MDS) was configured to travel on a path that would be coincident with the cochlea’s modiolar axis, w...

A variety of magnetic devices can be manipulated remotely using a single permanent “actuator” magnet positioned in space by a robotic manipulator. This paper describes the spherical-actuator-magnet manipulator (SAMM), which is designed to replace or augment the singularity-prone spherical wrist used by prior permanent-magnet manipulation systems. T...

Electromagnetic formation flight (EMFF) denotes a method of formation flight control in which a cluster of spacecraft are equipped with controllable magnetic dipoles for coordination of their relative positions using interdipole forces. We present a method for finding a minimum-power dipole solution for a given set of desired interdipole forces. We...

An admittance-type robotic manipulator is a nonbackdrivable device whose motion is controlled to move in response to a user-applied force, typically with velocity proportional to force. This study characterizes the ability of ten human subjects to accurately and precisely control the velocity of such a device, using force applied by the index finge...

Previous studies have shown that inclusion of arm swing in gait rehabilitation leads to more effective walking recovery in patients with walking impairments. However, little is known about the correct arm-swing trajectories to be used in gait rehabilitation given the fact that changes in walking conditions affect arm-swing patterns. In this paper w...

We present a telemanipulation system for retinal surgery that uses a full range of unmodified commercially available instruments. The system is compact and light enough that it could reasonably be made head-mounted to passively compensate for head movements. Two mechanisms are presented that enable the system to use commercial actuated instruments,...

This paper provides an optimal parametric design for tri-axial nested Helmholtz coils, which are used to generate a uniform magnetic field with controllable magnitude and direction. Circular and square coils, both with square cross section, are considered. Practical considerations such as wire selection, wire-wrapping efficiency, wire bending radiu...

This paper describes an improved control system for the Treadport immersive locomotion interface, with results that generalize to any treadmill that utilizes an actuated tether to enable self-selected walking speed. A new belt controller is implemented to regulate the user's position; when combined with the user's own volition, this controller also...

This paper demonstrates magnetic three-degree-of-freedom (3-DOF) closed-loop position and 2-DOF open-loop orientation control of a mockup magnetic capsule endoscope in fluid with a single permanent magnet positioned by a commercial 6-DOF robotic manipulator, using feedback of only the 3-DOF capsule position measured by a localization system, with a...

Experiments with scala-tympani (ST) phantoms are used to evaluate new electrode arrays and cochlear-implant insertion techniques. To date, phantoms have not accounted for clinical orientations and geometric differences between round-window (RW) insertions and anteroinferior cochleostomy insertions. For improved assessments of insertion experiments,...

This work examines a passive perching mechanism that enables a rotorcraft to grip branchlike perches and resist external wind disturbance using only the weight of the rotorcraft to maintain the grip. We provide an analysis of the mechanism's kinematics, present the static force equations that describe how the weight of the rotorcraft is converted i...

In this paper, we examine several magnetic control methods that utilize the fully controllable dipole field generated by the single stationary dipole source. Since the magnetic field generated by a dipole source is nonuniform, it applies both forces and torques to magnetic objects and can be used to manipulate magnetic tools. Recently, the Omnimagn...

A magnetic manipulation and navigation system for moving a magnetic element through a body comprising at least six electromagnets fixed in relation to said body and a control unit supplying the current for the electromagnets. The electromagnets have soft magnetic cores and the current supplied by the control unit to each of the electromagnets is ad...

This paper studies the behavior of rotating magnetic microrobots, constructed with a permanent magnet or a soft ferromagnet, when the applied magnetic field rotates faster than a microrobot's step-out frequency (the frequency requiring the entire available magnetic torque to maintain synchronous rotation). A microrobot's velocity dramatically decli...

To date, untethered magnetic devices actuated with a single rotating permanent magnet, such as active capsule endoscopes and magnetic microrobots, have been constrained to operate in positions where the rotating dipole field behavior is simple and easy to visualize. In this paper, we show how to generate a rotating magnetic field with any desired r...

This paper focuses on wire electrical discharge machining (WEDM) of devices made from commercially available sintered neodymium-iron-boron (NdFeB) rare-earth magnets that have been magnetized before machining. We conduct an experimental study to quantify the effects of the voltage and capacitance of an RC-type WEDM machine, as well as the magnet po...

This paper presents an analysis of the factors affecting the performance, workspace, and stability of untethered magnetic haptic interfaces, with the goal of informing the design of future devices. We differentiate untethered magnetic interfaces, which use a stylus with an embedded permanent magnet to interact with magnetic fields projected into sp...

A sensor for intraocular measurements moveable within at least one of an vitreous humor of an eye, an aqueous humor of an eye and an intraocular replacement medium. The sensor includes a magnetic body susceptible to magnetic fields and at least one sensor film.

An Omnimagnet is an omnidirectional electromagnet comprised of a ferromagnetic core inside of three orthogonal nested solenoids. It generates a magnetic dipole-field with both a variable dipole-moment magnitude and orientation with no moving parts. The design of an Omnimagnet, in which each solenoid has the same dipole moment and minimizes the diff...

Previous research on the localization of wireless capsule endoscopes with magnetic fields and sensors has typically utilized incremental methods. This paper provides a non-iterative solution to determine the six degree-of-freedom (6-DOF) position and orientation of a wireless capsule endoscope being actuated by a rotating magnetic dipole. Non-itera...

Untethered magnetic devices, such as magnetic microrobots and magnetically actuated capsule endoscopes, stand to significantly impact the field of minimally invasive medicine. These devices, which we refer to as magnetically actuated tools (MATs), are often controlled using electromagnets, which can be expensive to scale clinically. Due to their po...

Flying robots capable of perch-and-stare are desirable for reconnaissance missions. Inspired by an adaptation that enables songbirds to sleep in trees without active muscle control, the research presented herein details the design for a passive mechanism that enables a rotorcraft to perch reminiscent of a bird perching on a tree branch. Perching is...

The dipole approximation for magnetic fields has become a common simplifying assumption in magnetic-manipulation research when dealing with permanent magnets because the approximation provides convenient analytical properties that are a good fit at large distances. What is meant by “good fit at large distances” is generally not quantified in the li...

Piezoelectric stick-slip actuators have become the foundation of modern micromanipulation. Due to difficulty in closed-loop control with manipulators that use piezoelectric stick-slip actuators, methods for open-loop control with a human in the loop have been developed. The utility of such methods depends directly on the accuracy of the open-loop m...

The small intestine is the longest part of the gastrointestinal (GI) tract, but it is difficult to examine with traditional endoscopic procedures. To resolve this, swallowable capsules have been created that slowly pass through the entire GI tract taking images. Research is currently being done in magnetic actuation and localization to increase the...

This paper considers the requirements for stable control of simple devices that consist of a permanent magnet rigidly attached to a screw operating in soft tissue. Placing these devices in a rotating magnetic field causes the device's permanent magnet to rotate synchronously with the applied field, making the attached screw generate forward propuls...

Cochlear implants have become a standard treatment for many with severe to profound sensorineural hearing loss. However, delicate cochlear structures can be damaged during surgical insertion, which can lead to loss of residual hearing and decreased implant effectiveness. We propose a magnetic guidance concept in which a magnetically tipped cochlear...

The goal of this study is to compare the effect of training by the University of Utah's Treadport versus a conventional treadmill on gait improvement of spinal-cord-injury (SCI) patients. Four incomplete SCI subjects who had reached a rehabilitation plateau were selected to have training first on the treadmill and then the Treadport. Spatiotemporal...

Magnetically actuated tools (MATs) that utilize rotating magnetic fields for propulsion, such as active capsule endoscopes and magnetic microrobots, have typically been controlled using either arrangements of electromagnets or permanent-magnet systems operated in limited configurations. It was recently shown that a rotating magnetic field for MAT a...

It has been shown that when a magnetic dipole, such as a permanent magnet, is rotated around a fixed axis such that the dipole is perpendicular to the axis of rotation, the magnetic field vector at every point in space also rotates around a fixed axis. In this paper, we reformulate this phenomenon using linear algebraic techniques, which enables us...

Artificial bacterial microrobots are swimming microrobots that mimic the propulsion mechanism of bacteria, which use the rotation of helical filaments for motion genera-tion. The potential applications for bacteria-inspired microrobots are diverse, ranging from diagnostic and therapeutic tasks in vivo to probing, analyzing, and transporting microob...

For this study, we have collected puncture force data from the vasculature of the chorioallantoic membranes (CAM) of developing chicken embryos to examine forces required for retinal vein cannulation. The CAM vessels of a developing chicken embryo have been shown to be an appropriate model for human retinal veins. The effect of microneedle geometry...

Many current and proposed retinal procedures are at the limits of human performance and perception. Microrobots that can navigate the fluid in the interior of the eye have the potential to revolutionize the way the most difficult retinal procedures are conducted. Microrobots are typically envisioned as miniature mechatronic systems that utilize MEM...

We demonstrate that the attractive magnetic force acting on a rotating magnetic device (e.g., a magnetic microrobot), actuated using a rotating magnet dipole, can be converted into a lateral force by rotating the actuator dipole according to a specific open-loop trajectory. Results show rotating magnetic devices can be rolled and simultaneously pus...

Cochlear implants have become a standard treatment for many with severe to profound sensorineural hearing loss. However, delicate cochlear structures can be damaged during surgical insertion, which can lead to loss of residual hearing and decreased implant effectiveness. We propose a magnetic guidance concept in which a magnetically tipped cochlear...

Commercial micro/nano-manipulators, which utilize piezoelectric stick-slip actuators to achieve high precision over a large workspace, are currently controlled by a human operator at the joint level, leading to unintuitive and time-consuming teleoperation. Prior work has considered the use of computer-vision-feedback to close a control loop for imp...

Flying robots capable of perch-and-stare are desir- able for reconnaissance missions. Current solutions for perch- and-stare applications utilize various methods to create an air- craft that can land on a limited set of surfaces that are typically horizontal or vertical planes. This paper presents a bio-inspired concept that allows for passive perc...

Flying robots capable of perch-and-stare are desirable for reconnaissance missions. Current solutions for perch-and-stare applications utilize various methods to create an aircraft that can land on a limited set of surfaces that are typically horizontal or vertical planes. This paper presents a bio-inspired concept that allows for passive perching...

Human–robot collaborative systems have the potential to dramatically change many aspects of surgery, manufacturing, hazardous-material handling, and other dextrous tasks. We are particularly interested in precise manipulation tasks, which are typically performed under an admittance-control regime, where the controlled velocity of a non-backdrivable...

In cochlear-implant (CI) insertion experiments, scala-tympani (ST) phantoms are often used in place of in vivo studies or ca-daver studies. During the development of novel CI technology, a scaled-up phantom is often desirable. In this paper, we create a scalable model of the human ST by synthesizing published ana-tomical data and images. We utilize...

We demonstrate five-degree-of-freedom (5-DOF) wireless magnetic control of a fully untethered microrobot (3-DOF position and 2-DOF pointing orientation). The microrobot can move through a large workspace and is completely unrestrained in the rotation DOF. We accomplish this level of wireless control with an electromagnetic system that we call OctoM...

Future retinal therapies will be partially automated in order to increase the positioning accuracy of surgical tools. Proposed untethered microrobotic approaches that achieve this increased accuracy require localization information for their control. Since the environment of the human eye is externally observable, images can be used to localize the...

Microrobots have the potential to revolutionize many aspects of medicine. These untethered, wirelessly controlled and powered devices will make existing therapeutic and diagnostic procedures less invasive and will enable new procedures never before possible. The aim of this review is threefold: first, to provide a comprehensive survey of the techno...

We demonstrate how two Novint Falcons, inexpensive commercially available haptic devices, can be modified to a create a reconfigurable five-degree-of-freedom (5-DOF) haptic device for less than $500 (including the two Falcons). The device is intended as an educational tool to allow a broader range of students to experience force and torque feedback...

Magnetic helical medical microrobots are promising for use in open fluid, lumen, and soft-tissue environments and will enable minimally invasive access to hard-to-reach locations in the body. Prior work focused on control via uniform magnetic fields from orthogonal arrangements of electromagnetic coils, which are difficult to scale up to the size r...

Human-robot collaborative systems (HRCS) have the potential to dramatically change many aspects of surgery, manufacturing, hazardous-material handling, and other dextrous tasks. We are particularly interested in precise manipulation tasks, which are typically performed under an admittance-control regime, where the controlled velocity is proportiona...

We demonstrate five-degree-of-freedom (5-DOF) wireless magnetic control of a fully untethered microrobot with a magnetic steering system we call OctoMag. Although only occupying a single hemisphere, this system is capable of isotropically applying forces on the order of 1–40 µN with unrestricted control of the 2 orienting DOF. These capabilities ar...

We demonstrate five-degree-of-freedom (5-DOF) wireless magnetic control of a fully untethered microrobot with a magnetic steering system we call OctoMag. Although only occupying a single hemisphere, this system is capable of isotropically applying forces on the order of 1-40 μN with unrestricted control of the 2 orienting DOF. These capabilities ar...

Self-assembly is a process in which individual components form an organized structure as a consequence of local interactions. When using magnetics to create interaction forces, the magnetic flux distribution of a self-assembling system changes as its assembly state varies. Since Hall effect sensors are a convenient and effective means to detect cha...

Artificial bacterial flagella (ABF) are swimming microrobots that mimic the swimming motion of bacteria. The helical swimmer consists of an InGaAs/GaAs/Cr helical nanobelt tail fabricated by a self-scrolling technique with dimensions similar to a natural flagellum, and a thin soft-magnetic metal ¿head¿ consisting of a Cr/Ni/Au multi-layer. The sw...

Future retinal therapies will be partially automated in order to increase the surgeons' ability to operate near the sensitive structure of the human eye retina. Untethered robotic devices that achieve the desired precision have been proposed, but require localization information for their control. Since the interior of the human eye is externally o...

Microrobots have the potential to dramatically change many aspects of medicine by navigating through bodily fluids to perform targeted diagnosis and therapy. Researchers have proposed numerous micro-robotic swimming methods, with the vast majority utilizing magnetic fields to wirelessly power and control the microrobot. In this paper, we compare th...

Artificial bacterial flagella (ABFs) consist of helical tails resembling natural flagella fabricated by the self-scrolling of helical nanobelts and soft-magnetic heads composed of Cr/Ni/Au stacked thin films. ABFs are controlled wirelessly using a low-strength rotating magnetic field. Self-propelled devices such as these are of interest for in vitr...

Vitreoretinal surgeries require accuracy and dexterity that is often beyond the capabilities of human surgeons. Untethered robotic devices that can achieve the desired precision have been proposed, and localization information is required for their control. Since the interior of the human eye is externally observable, vision can be used for their l...

Successful ophthalmic surgeries using intraocular untethered microrobots or tethered robotic microtools require methods to robustly track the microdevices in the posterior of the human eye. The dimensions and specularities of the microdevices are major obstacles for accurate tracking. In addition, the optical structure of the human eye makes it cha...

Inspired by the natural design of bacterial flagella, we report artificial bacterial flagella (ABF) that have a comparable shape and size to their organic counterparts and can swim in a controllable fashion using weak applied magnetic fields. The helical swimmer consists of a helical tail resembling the dimensions of a natural flagellum and a thin...

The ,success of capsule ,endoscopy ,has ,promoted ,the development ,of the ,next generation of endoluminal surgical devices, and many research groups have proposed robotic capsules with novel functionalities, such as active locomotion and surgical intervention capabilities. Yet, these capsules are still single robotic units with a limited number of...

Microrobots that can navigate bodily fluids will enable localized sensing and targeted drug delivery in parts of the body that are currently inaccessible or too invasive to access. Microrobots are typically envisioned as miniature mechatronic systems that utilize MEMS technology to incorporate sensing and actuation onboard. This paper presents a si...

Untethered microrobotic devices have been proposed for use in ophthalmic surgeries, and localization information is required for their control. The environment of the human eye is externally observable, and images can be used to localize intraocular agents. There is currently no quantitative description of the effects of the human eye optics on ima...

There is a clear trend toward the miniaturization of medical devices for minimally invasive medical procedures, ranging from diagnosis and targeted drug delivery to complex surgical interventions. Current research focuses on increasing the functionality of commercially successful capsule endoscope technology by developing active locomotion and tele...

Few rotational actuators currently exist with the ability to transmit motion at different speeds, torques, and directions at the nanometer scale. We present work regarding the application of helical nanobelts as linear-to-rotary and rotary-to-linear motion converters. We discuss their ability to rectify device rotation to linear motion for untether...

Retinal vein occlusion is an obstruction of blood flow due to clot formation in the retinal vasculature, and is among the most common causes of vision loss. Currently, the most promising therapy involves injection of t-PA directly into small and delicate retinal vessels. This procedure requires surgical skills at the limits of human performance. In...

Capitalizing on advances in CMOS and MEMS technologies, microrobots have the potential to dramatically change many aspects of medicine by navigating bodily fluids to perform targeted diagnosis and therapy. Onboard energy storage and actuation is very difficult at the microscale, but externally applied magnetic fields provide an unparalleled means o...

The influence of oxygen on various ophthalmological complications is not completely understood and intraocular oxygen measurements are essential for better diagnosis and treatment. A magnetically controlled wireless sensor device is proposed for minimally invasive intraocular oxygen concentration measurements. This device will make it possible to m...

Few rotational actuators currently exist with the ability to transmit motion at different speeds, torques, and directions at the nanometer scale. We present work regarding the application of helical nanobelts as linear-to-rotary and rotary-to-linear motion converters. We discuss their ability to rectify device rotation to linear motion for untether...

We calculate the torque and force generated by an arbitrary magnetic field on an axially symmetric soft-magnetic body. We consider the magnetization of the body as a function of the applied field, using a continuous model that unifies two disparate magnetic models. The continuous torque and force follow. The model is verified experimentally, and ca...

We calculate the torque and force generated by an arbitrary magnetic field on an axially symmetric soft-magnetic body. We consider the magnetization of the body as a function of the applied field, using a continuous model that unifies two disparate magnetic models. The continuous torque and force follow. The model is verified experimentally, and ca...

Modular microrobots will enable exploration and manipulation in tiny and difficult to access spaces. Modularity allows reconfiguration for adaptation to unstructured environments. In addition, individual modules can be designed for simple specific functions, thereby reducing fabrication complexity and easing downscaling. For modular microrobots, a...

The influence of oxygen on various ophthalmologic complications is not completely understood and intraocular oxygen measurements are essential for better diagnosis and treatment. A magnetically controlled wireless sensor device is proposed for minimally invasive intraocular oxygen concentration measurements. This device will make it possible to mak...

In this paper we present a protocol to create artificial vitreous humor phantom tissue to be used as a test bed for in vitro experiments. The artificial vitreous consists of water, agar, and hyaluronic acid. Unlike existing vitreous replacement substances, this dummy tissue exhibits viscoelastic characteristics of in vivo natural vitreous humor. We...

This article provided an overview of the field of microrobotics, including the distinct but related topics of micromanipulation and microrobots. While many interesting results have been shown to date, the greatest results in this field are yet to come.

Microrobots experience physical phenomena that are difficult to model analytically and that are not completely captured with macro-scale prototypes. In this paper we present a reconfigurable robotic measurement system to characterize the magnetic and hydrodynamic properties of assembled-MEMS microrobots. The system consists of a powerful permanent...

Pulse frequency modulation (PFM) is a method of encoding information where the instantaneous frequency of a pulse train carries the signal's information. PFM is of particular interest to those working towards interfacing prosthetic devices directly with the human nervous system. In this paper, we consider the effects of directly implementing PFM wi...

The influence of oxygen on various ophthalmologic complications is not completely understood and intraocular oxygen measurements are essential for better diagnosis and treatment. A magnetically controlled wireless sensor device is proposed for minimally invasive intraocular oxygen concentration measurements. This device will make it possible to mak...

In this paper we present a protocol to create artificial vitreous humor phantom tissue to be used as a test bed for in vitro experiments. The artificial vitreous consists of water, agar, and hyaluronic acid. Unlike existing vitreous replacement substances, this dummy tissue exhibits viscoelastic characteristics of in vivo natural vitreous humor. We...

Pseudo-admittance is introduced as a novel bilateral telemanipula-tion system that is designed to mimic proportional-velocity admittance control on systems where the master is an impedance-type robot. The controller generalizes to systems with slave robots of the impedance or admittance type. Pseudo-admittance uses a proxy with admittance dynamics...

Microrobots have the potential to dramatically change many aspects of medicine by navigating bodily fluids to perform targeted diagnosis and therapy. Researchers have proposed numerous microrobotic swimming methods, with the vast majority utilizing magnetic fields to wirelessly power and control the microrobot. In this paper, we theoretically and e...