R-3 Repository :: Browsing by Author "O'Malley, Marcia K."

Browsing by Author "O'Malley, Marcia K."

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An Automated System for Cryo-Electron Microscopy Sample Preparation
(2011) Thompson, Zachary J.; O'Malley, Marcia K.
Cryo-electron microscopy (CryoEM) is a procedure that has become popular for imaging radiation intolerant structures under electron microscopes. CryoEM involves maintaining the sample at cryogenic temperatures throughout the imaging process This has the effect of minimizing damage caused by the electron beam, and results in higher quality images than can be obtained through more traditional imaging methods. The preparation of samples for cryo-electron microscopy studies is currently a labor and time intensive process. Samples must be applied to an imaging substrate under tightly controlled environmental conditions, formed into a thin film, vitrified with liquid ethane, and placed into temporary storage under cryogenic conditions. The grid preparation process is very sensitive to procedural factors, thus the successful creation of viable samples depends on tightly controlling the conditions under which grids are prepared. Several devices which automate portions of the specimen preparation process are currently in use; however, these systems heavily rely on a human operator to function properly. This thesis describes a system that is capable of fully automating the sample preparation process. The resulting system minimizes the need for human input during specimen preparation, improves process control, and provides similar levels of environmental control. Testing shows that the resulting system is capable of preparing samples without human interaction.
An exploration of grip force regulation with a low-impedance myoelectric prosthesis featuring referred haptic feedback
(BioMed Central, 2015) Brown, Jeremy D.; Paek, Andrew; Syed, Mashaal; O'Malley, Marcia K.; Shewokis, Patricia A.; Contreras-Vidal, Jose L.; Davis, Alicia J.; Gillespie, R.B.
Background: Haptic display technologies are well suited to relay proprioceptive, force, and contact cues from a prosthetic terminal device back to the residual limb and thereby reduce reliance on visual feedback. The ease with which an amputee interprets these haptic cues, however, likely depends on whether their dynamic signal behavior corresponds to expected behaviors—behaviors consonant with a natural limb coupled to the environment. A highly geared motor in a terminal device along with the associated high back-drive impedance influences dynamic interactions with the environment, creating effects not encountered with a natural limb. Here we explore grasp and lift performance with a backdrivable (low backdrive impedance) terminal device placed under proportional myoelectric position control that features referred haptic feedback. Methods: We fabricated a back-drivable terminal device that could be used by amputees and non-amputees alike and drove aperture (or grip force, when a stiff object was in its grasp) in proportion to a myoelectric signal drawn from a single muscle site in the forearm. In randomly ordered trials, we assessed the performance of N=10 participants (7 non-amputee, 3 amputee) attempting to grasp and lift an object using the terminal device under three feedback conditions (no feedback, vibrotactile feedback, and joint torque feedback), and two object weights that were indiscernible by vision. Results: Both non-amputee and amputee participants scaled their grip force according to the object weight. Our results showed only minor differences in grip force, grip/load force coordination, and slip as a function of sensory feedback condition, though the grip force at the point of lift-off for the heavier object was significantly greater for amputee participants in the presence of joint torque feedback. An examination of grip/load force phase plots revealed that our amputee participants used larger safety margins and demonstrated less coordination than our non-amputee participants. Conclusions: Our results suggest that a backdrivable terminal device may hold advantages over non-backdrivable devices by allowing grip/load force coordination consistent with behaviors observed in the natural limb. Likewise, the inconclusive effect of referred haptic feedback on grasp and lift performance suggests the need for additional testing that includes adequate training for participants.
Analysis of human movement for a complex dynamic task: What predicts success?
(2013-09-16) Purkayastha, Sagar; O'Malley, Marcia K.; Byrne, Michael D.; Dick, Andrew J.
This thesis identiﬁes and analyzes successful movement strategies for the completion of a complex dynamic task. In the past it has been shown that movement strategies correlate well to performance for simple tasks. Therefore, in this thesis I was motivated to ﬁnd out if motion based metrics correlated well to performance for more complicated motor tasks. First, the Nintendo Wiimote was veriﬁed as a suitable gaming interface enabling gross human motion capture through experimental comparisons with other gaming interfaces and precision sensors. Then, a complex motor task was rendered in an open-source gaming environment. This environment enabled the design of a rhythmic task that could be controlled with the Wiimote while data were simultaneously recorded for later analysis. For the task, success and failure could be explained by high correlation between two motion based performance metrics, mean absolute jerk (MAJ) and average frequency (AVF) per trial. A logistic regression analysis revealed that each subject had a range of MAJ and AVF values for being successful, outside of which they were unsuccessful. Therefore, this thesis identiﬁes motion based performance metrics for a novel motor control task that is signiﬁcantly diﬃcult to master and the techniques used to identify successful movement strategies can be used for predicting success for other such complex dynamic tasks.
Application of sequential auction techniques to nonlinear targeting assignment for space-delivered entry vehicles
(2004) Stiles, Brian Allan; O'Malley, Marcia K.
In the future, the arsenal of the U.S. military will include Space-delivered weapons, released by reusable launch vehicles. Entry vehicles released from the launch platforms will be capable of guiding to target locations throughout the world. In order to adequately incorporate these weapons into military plans, theater commanders will require sophisticated planning algorithms to maximize the likelihood of destroying the most important targets. This thesis develops a target assignment algorithm which uses a sequence of linear auctions to optimize the assignment of entry vehicles to weighted targets. This result can be improved over time by use of a directed search method, which uses numerous sequences of linear auctions to improve on solutions by eliminating poor assignments. These methods are compared to greedy methods, showing improvement in the assignment solution.
Assessing Wrist Movement With Robotic Devices
(IEEE, 2018) Rose, Chad G.; Pezent, Evan; Kann, Claudia K.; Deshpande, Ashish D.; O'Malley, Marcia K.
Robotic devices have been proposed to meet the rising need for high intensity, long duration, and goal-oriented therapy required to regain motor function after neurological injury. Complementing this application, exoskeletons can augment traditional clinical assessments through precise, repeatable measurements of joint angles and movement quality. These measures assume that exoskeletons are making accurate joint measurements with a negligible effect on movement. For the coupled and coordinated joints of the wrist and hand, the validity of these two assumptions cannot be established by characterizing the device in isolation. To examine these assumptions, we conducted three user-in-the-loop experiments with able-bodied participants. First, we compared robotic measurements to an accepted modality to determine the validity of joint- and trajectory-level measurements. Then, we compared those movements to movements without the device to investigate the effects of device dynamic properties on wrist movement characteristics. Last, we investigated the effect of the device on coordination with a redundant, coordinated pointing task with the wrist and hand. For all experiments, smoothness characteristics were preserved in the robotic kinematic measurement and only marginally impacted by robot dynamics, validating the exoskeletons for use as assessment devices. Stemming from these results, we propose design guidelines for exoskeletal assessment devices.
Characterization of a hand-wrist exoskeleton, READAPT, via kinematic analysis of redundant pointing tasks
(IEEE, 2015) Rose, Chad G.; Sergi, Fabrizio; Yun, Youngmok; Madden, Kaci; Deshpande, Ashish D.; O'Malley, Marcia K.; Mechatronics and Haptic Interfaces Laboratory
Training coordinated hand and wrist movement is invaluable during post-neurological injury due to the anatomical, biomechanical, and functional couplings of these joints. This paper presents a novel rehabilitation device for coordinated hand and wrist movement. As a first step towards validating the new device as a measurement tool, the device transparency was assessed through kinematic analysis of a redundant finger pointing task requiring synergistic movement of the wrist and finger joints. The preliminary results of this new methodology showed that wearing the robot affects the kinematic coupling of the wrist and finger for unconstrained pointing tasks. However, further experiments specifying a subset of the solution manifold did not exhibit the same difference between robot and no robot trials. The experiments and analysis form a promising method for the characterization of multi-articular wearable robots as measurement tools in robotic rehabilitation.
Clinical Evaluation of an Upper Limb Exoskeleton for Rehabilitation After Incomplete Spinal Cord Injury
(2015-04-21) Fitle, Kyle D; O'Malley, Marcia K.; Dick, Andrew J; Kortum, Philip T
In recent years robotic rehabilitation has emerged as an effective rehabilitation tool for motor impairment caused by multiple types of injuries and ailments. Incomplete spinal cord injury (SCI) is one of the injury types which is a prime candidate for robotic rehabilitation, but this field is relatively young and unexplored. The MAHI Exo II is a five degree-of-freedom (DOF) robotic exoskeleton which was designed for rehabilitation of the upper-limb following SCI or stroke. Upper-limb impairment is one of the factors which SCI patients rate as most significant in their post-injury decrease in quality of life. Therefore, the MAHI Exo II has the potential to make strides in improving the quality of life of patients in novel ways. This thesis presents research which has been done towards this aim. The first section presents a study on incomplete SCI rehabilitation with the MAHI Exo II. This study used the robotic system to provide resistance therapy for elbow flexion/extensioin, forearm pronation/supination, wrist flexion/extension, and wrist radial/ulnar deviation. The robot was also used to record position data in a backdriving-evaluation mode in order to analyze the change in subject movement quality over the course of therapy using several robotic quality of movement metrics. Subject improvement was also measured by standard clinical impairment measures used for SCI. Ten subjects enrolled in the study and eight finished the entire protocol. The results of this study spurred further research into more effective control and treatment strategies for the MAHI Exo II. In the second portion of this thesis, I present details on the Assist-as-Needed rehabilitation study. This experiment sought to apply assistive therapy with the MAHI Exo II using a novel adaptive control strategy and compare it to a non-adaptive controller in a parallel controlled study. This type of comparison has not been done before for robotic rehabilitation. The assistive nature of the controller allowed a wider inclusion criteria for incomplete SCI. The same joints were trained in this study and most of the same clinical and robotic measures were used to evaluate motor ability improvement. One of the secondary features of the study design is the sequential group assignment with co-variates minimization. The study is currently in progress at the time of this writing, but some preliminary results are presented in this section.
Closed form guidance laws for intercepting moving targets
(2004) Bartley, Christopher S.; O'Malley, Marcia K.
A family of air-to-surface guidance laws designed to intercept moving targets has been developed. They include the effect of gravity, as well as constraints on the terminal flight path and heading angle, and are designed for tracking moving targets. These guidance laws yield equations for the commanded accelerations. They are based firmly on optimal control theory and meet the first and second variation necessary conditions that originate from Pontryagin's Minimum Principle. In addition, these solutions also meet the second variation sufficient conditions for a minimum. They have been evaluated in six degree of freedom simulations. The results show that they perform as designed, even for airframes which are rather sluggish.
Conveying language through haptics: a multi-sensory approach
(ACM, 2018) Dunkelberger, Nathan; Sullivan, Jenny; Bradley, Joshua; Walling, Nickolas P.; Manickam, Indu; Dasarathy, Gautam; Israr, Ali; Lau, Frances W.Y.; Klumb, Keith; Knott, Brian; Abnousi, Freddy; Baraniuk, Richard; O'Malley, Marcia K.
In our daily lives, we rely heavily on our visual and auditory channels to receive information from others. In the case of impairment, or when large amounts of information are already transmitted visually or aurally, alternative methods of communication are needed. A haptic language offers the potential to provide information to a user when visual and auditory channels are unavailable. Previously created haptic languages include deconstructing acoustic signals into features and displaying them through a haptic device, and haptic adaptations of Braille or Morse code; however, these approaches are unintuitive, slow at presenting language, or require a large surface area. We propose using a multi-sensory haptic device called MISSIVE, which can be worn on the upper arm and is capable of producing brief cues, sufficient in quantity to encode the full English phoneme set. We evaluated our approach by teaching subjects a subset of 23 phonemes, and demonstrated an 86% accuracy in a 50 word identification task after 100 minutes of training.
Current trends in robot-assisted upper-limb stroke rehabilitation: promoting patient engagement in therapy
(Springer, 2014) Blank, Amy A.; French, James A.; Pehlivan, Ali Utku; O'Malley, Marcia K.
Stroke is one of the leading causes of long-term disability today; therefore, many research efforts are focused on designing maximally effective and efficient treatment methods. In particular, robotic stroke rehabilitation has received significant attention for upper-limb therapy due to its ability to provide high-intensity repetitive movement therapy with less effort than would be required for traditional methods. Recent research has focused on increasing patient engagement in therapy, which has been shown to be important for inducing neural plasticity to facilitate recovery. Robotic therapy devices enable unique methods for promoting patient engagement by providing assistance only as needed and by detecting patient movement intent to drive to the device. Use of these methods has demonstrated improvements in functional outcomes, but careful comparisons between methods remain to be done. Future work should include controlled clinical trials and comparisons of effectiveness of different methods for patients with different abilities and needs in order to inform future development of patient-specific therapeutic protocols.
Design and control of a haptic arm exoskeleton
(2004) Gupta, Abhishek; O'Malley, Marcia K.
Robot-assisted physical therapy has been shown to aid in the rehabilitation process following neurological injuries. As a therapeutic or training tool, the robot provides a means to implement and evaluate assistance cues to the operator's arm in addition to displaying the forces arising from the dynamics of the virtual environment. Furthermore, training in virtual environments also provides increased repeatability, scalability, safety and a greater control on the experimental setup over training in natural environments. This thesis presents the analysis of various design constraints that apply to the design of such devices. In this context, the author also presents the design of a five degree-of-freedom haptic arm exoskeleton designed for training and rehabilitation in virtual environments. The device has high structural stiffness, minimal backlash, low friction and absence of mechanical singularities in the workspace, which are some of the properties that characterize high quality haptic interfaces. A scheme for the force control of the robot, using a novel joint-based methodology is also presented.
Design and Control of an Exoskeletal Rehabilitation Device for Stroke and Spinal Cord Injury Patients
(2012) Pehlivan, Ali Utku; O'Malley, Marcia K.
Robotic rehabilitation has gained significant traction in recent years, due to the clinical demonstration of its efficacy in restoring function for upper extremity movements and locomotor skills, demonstrated primarily in stroke populations. In this thesis, I present the design of MAHI Exo-II, a robotic exoskeleton for rehabilitation of the upper extremity after stroke, spinal cord injury, or other brain injuries. The five degree-of-freedom robot enables elbow flexion-extension, forearm pronation-supination, wrist flexion-extension, and radial-ulnar deviation. In the first part of this thesis, hardware design of the system is presented. The device offers several significant design improvements compared to its predecessor, MAHI Exo I. Specifically, issues with backlash and singularities in the wrist mechanism have been resolved, torque output has been increased in the forearm and elbow joints, a passive degree of freedom has been added to allow shoulder abduction thereby improving alignment especially for users who are wheelchairbound, and the hardware now enables simplified and fast swapping of treatment side. These modifications are discussed in the thesis, and results for the range of motion and maximum torque output capabilities of the new design and its predecessor are presented. In the second part of this thesis. I present the modification and implementation of a previously reported linear position and force control to MAHI Exo-II. The modified controller includes three different modes which are designed for use with patients with different levels of severity of injury. These modes either completely assist or resist the patient during the movement. Next, I present the implementation of a previously proposed nonlinear control algorithm in simulation for the forearm and wrist module of MAHI Exo-II. The proposed nonlinear controller aims to provoke a compliant characteristic to the device and assist the patient only as much as needed. Finally, the result of clinical testing of the feasibility of the mechanical design and the efficacy of the control modes with a 28-year-old female SCI patient are presented.
Development of an educational device and accompanying laboratory series for instruction in an undergraduate engineering course
(2007) Bowen, Kevin; O'Malley, Marcia K.
The literature in engineering education research suggests that a cohesive series of laboratory exercises improves the learning and retention of the material presented in a laboratory course. The literature presents various devices that serve as the focus of a cohesive laboratory series. These devices and their accompanying laboratory series are designed to engage the students and generate enthusiasm in the course. One such device is the Haptic Paddle: a low cost single degree-of-freedom force-reflecting joystick that has enjoyed successful implementations in laboratory courses at other academic institutions. This thesis presents an adaptation of the Haptic Paddle and its accompanying laboratory series to meet specific goals for implementation in the laboratory component of the MECH 343: Modeling Dynamic Systems course offered at Rice University. Additionally, the device was developed to be an attractive platform for dissemination to colleagues who are interested in collaborating in engineering education research.
Development of Multisensory Haptic Cues for Prosthesis Feedback and Control
(2021-04-29) Fleck, Joshua J.; O'Malley, Marcia K.
Upper-limb prosthetic devices are an important tool in restoring functional ability following amputation. To meet user needs for better control and articulation, many electrically powered and digitally controlled systems have been developed to expand the capabilities of these devices. As these systems become more complex and integrate more actuation and sensing capabilities, there is an increasing need for suitable feedback mechanisms to improve user control and embodiment. Multisensory haptics, which combines multiple channels of tactile feedback, is one promising avenue by which this control loop can be accomplished. However, research in multisensory wearable devices has shown a number of factors that may complicate their usage, primarily in regards to user difficulty in perceiving simultaneously presented haptic cues. To assess and address these concerns, a test system for multisensory devices was constructed and experiments were performed to examine discrete and continuous multisensory cue perception. This thesis presents this experimental process, as well as the implications of these psychophysical factors and of prosthesis feedback in general for the design of multisensory haptic feedback for prosthetic applications.
Disturbance observer based closed loop control of haptic interfaces
(2008) Gupta, Abhishek; O'Malley, Marcia K.
Traditionally, control of haptic interfaces is achieved using open-loop impedance or admittance control. During open-loop control, the quality of haptic feedback is limited by the dynamics of the haptic device. Further improvements in quality of the haptic feedback require the use of closed-loop control techniques. Closed loop control of haptic interfaces is limited due to stability and cost considerations associated with closed loop force control. In this work, a non-linear disturbance observer for estimating human-machine contact forces during haptic interactions is presented. These estimated forces are then used for closed loop impedance control of the haptic interface. Globally exponential stability of the disturbance observer under the assumption of slowly varying disturbances is demonstrated. Finally, simulation and experimental results corresponding to disturbance observer based closed-loop control of a haptic interface are provided. Qualitative as well as quantitative comparison of the performance of disturbance observer-based control with traditional open and closed loop controllers is presented. In addition to control of haptic interfaces, the disturbance observer can be employed for contact force estimation between the slave and environment during teleoperation.
Electromyographic Classification to Control the SPAR Glove
(Elsevier, 2021) Britt, John E.; O'Malley, Marcia K.; Rose, Chad G.
The SeptaPose Assistive and Rehabilitative (SPAR) Glove has been developed to assist individuals with upper extremity impairment arising from neuromuscular injury. The glove detects user intent via the MYO wearable electromyography (EMG) device. In this manuscript, pattern recognition tools infer the desired hand pose from EMG activity. The ability of the measurement and classification methods to distinguish between hand poses was evaluated with nine able-bodied participants and three participants with spinal cord injury (SCI) in an offline experiment. The strong performance of the proposed intent detection method is shown in the steady-state classification accuracy, presented as confusion matrices, as well as the average confidence for each classification. Building upon the strong performance in detecting pose, a pilot study with two participants with SCI presents the initial results of the real-time implementation of the system, which suggests directions for future work in improving the steady-state classification accuracy through expanded measurement and a refined taxonomy to enable intuitive control.
Enabling Robots to Infer How End-Users Teach and Learn Through Human-Robot Interaction
(IEEE, 2019) Losey, Dylan P.; O'Malley, Marcia K.
During human-robot interaction, we want the robot to understand us, and we want to intuitively understand the robot. In order to communicate with and understand the robot, we can leverage interactions, where the human and robot observe each other's behavior. However, it is not always clear how the human and robot should interpret these actions: a given interaction might mean several different things. Within today's state of the art, the robot assigns a single interaction strategy to the human, and learns from or teaches the human according to this fixed strategy. Instead, we here recognize that different users interact in different ways, and so one size does not fit all. Therefore, we argue that the robot should maintain a distribution over the possible human interaction strategies, and then infer how each individual end-user interacts during the task. We formally define learning and teaching when the robot is uncertain about the human's interaction strategy, and derive solutions to both problems using Bayesian inference. In examples and a benchmark simulation, we show that our personalized approach outperforms standard methods that maintain a fixed interaction strategy.
Enhancing Haptic Communication with a Wearable Device and Tactile Alphabet
(2021-04-21) Alexander, Stephen Anthony; O'Malley, Marcia K.
Communication is a cornerstone of human operations. However, there are many scenarios where communication through normal means is not possible, due to visual and aural sensory saturation or impairment. Our sense of touch provides an alternative channel through which we can communicate, and haptic devices give us a means through which we can harness this channel's potential. Multi-sensory haptic devices, which use multiple forms of haptic stimuli, are capable of providing large sets of haptic information, without becoming too large or bulky. However, the most effective approaches to multi-sensory design and haptic communication are yet to be determined. In this thesis, methods of haptic communication through discrete language components are tested. Haptic communication through discrete language components involves the sequential haptic presentations of building blocks for speech, to convey words. Letters and phonemes were tested and compared as discrete language components to determine which language component is superior for haptic communication. Results indicated that letters were superior for haptic communication for both word perception accuracy and response time. Further, a multi-sensory haptic device that uses vibration and squeeze is presented. The device, MISSIVE-2 was evaluated through an absolute identification experiment. Results showed a high level of haptic cue perception accuracy.
Expert Surgeons Can Smoothly Control Robotic Tools With a Discrete Control Interface
(IEEE, 2019) O'Malley, Marcia K.; Byrne, Michael D.; Estrada, Sean; Duran, Cassidy; Schulz, Daryl; Bismuth, Jean
Objective assessment of surgical skill is gaining traction in a number of specialty fields. In robot-assisted surgery in particular, the availability of data from the operating console and patient-side robot offers the potential to derive objective metrics of performance based on tool movement kinematics. While these techniques are becoming established in the laparoscopic domain, current assessment techniques for robotic endovascular surgery are based primarily on observation, checklists, and grading scales. This work presents an objective and quantitative means of measuring technical competence based on analysis of the kinematics of endovascular tool tip motions controlled with a robotic interface. We designed an experiment that recorded catheter tip movement from 21 subjects performing fundamental endovascular robotic navigation tasks on a physical model. Motion-based measures of smoothness (spectral arc length and number of submovements) were computed and tested for correlation with subjective scores from a global rating scale assessment tool that has been validated for use when performing manual catheterization. Results show that the smoothness metrics that produced significant correlations with the global rating scale for manual catheterization show similar correlations for robotic catheterization. This finding is notable, since with the robotic interface, tool tip motion is commanded discretely via a control button interface, while in manual procedures the tools are controlled through continuous movements of the surgeon's hands. Logistic regression analysis using a single motion metric was capable of classifying subjects by expertise with better than 90% accuracy. These objective and quantitative metrics that capture movement quality could be incorporated into future training protocols to provide detailed feedback on trainee performance.
Functional representation and manipulation of shapes with applications in surface and solid modeling
(2013-09-16) Feng, Powei; Warren, Joe; Goldman, Ron; O'Malley, Marcia K.
Real-valued functions have wide applications in various areas within computer graphics. In this work, we examine three representation of shapes using functions. In particular, we study the classical B-spline representation of piece-wise polynomials in the univariate domain. We provide a generalization of B-spline to the bivariate domain using intuition gained from the univariate construction. We also study the popular scheme of representing 3D density distribution using a uniform, rectilinear grid, where we provide a novel contouring scheme that culls occluded inner geometries. Lastly, we examine a ray-based representation for 3D indicator functions called ray-rep, for which we present a novel meshing scheme with multi-material extensions.

Browsing by Author "O'Malley, Marcia K."

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