Engineering Commons^™

Multi-Homotopy Class Optimal Path Planning For Manipulation With One Degree Of Redundancy, Jacob J. Rice, Joseph M. Schimmels

Mechanical Engineering Faculty Research and Publications

Redundant manipulators have an infinitely large set of joint paths that yield a desired end-effector path in the task space. A unique joint path can be obtained by minimizing a global cost function. Prior optimal control methods minimize a global cost function to find a local minimum within a homotopy class. Many possible locally optimal joint paths are in different homotopy classes. This paper presents an algorithm that effectively searches the solution space and finds many locally optimal paths in all relevant homotopy classes. The path with the lowest cost is very likely the globally optimal path. The algorithm is …

Effects Of Spinal Fusion For Idiopathic Scoliosis On Lower Body Kinematics During Gait, Karen M. Kruger, Christina R. Garman, Joseph J. Krzak, Adam Graf, Sahar Hassani, Sergey Tarima, Peter F. Sturm, Kim W. Hammerberg, Purnendu Gupta, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Objectives

The purpose of this study was to compare gait among patients with scoliosis undergoing posterior spinal fusion and instrumentation (PSFI) to typically developing subjects and determine if the location of the lowest instrumented vertebra impacted results.

Summary of Background Data

PSFI is the standard of care for correcting spine deformities, allowing the preservation of body equilibrium while maintaining as many mobile spinal segments as possible. The effect of surgery on joint motion distal to the spine must also be considered. Very few studies have addressed the effect of PSFI on activities such as walking and even fewer address …

Inverse Kinematic Assessment Of Rehabilitative Therapy In Children Using Orthotics, Michael P. Murphy, Jacob R. Rammer, Kaleb L. Vinohout, Meghan R. Caballero, Christy M. Cornwell, Jessica M. Fritz, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Pathologic movement patterns are characterized by abnormal kinematics that alter how muscles support the body during walking. Individual muscles are often the target of interventions with physical therapy and surgery alike, yet the tools to assess individual muscles clinically remain limited. The aim of this study is to assess OpenSim as a clinical tool for individualized rehabilitative evaluation of children using orthotics. This anatomic and kinematic modeling study was focused on pre- and post-treatment assessment of gait characteristics in fourteen children using orthotic devices. A range of four to twelve acceptable gait capture trials was collected for each child before …

Parallel Reference Speaker Weighting For Kinematic-Independent Acoustic-To-Articulatory Inversion, An Ji, Michael T. Johnson, Jeffrey J. Berry

Speech Pathology and Audiology Faculty Research and Publications

Acoustic-to-articulatory inversion, the estimation of articulatory kinematics from an acoustic waveform, is a challenging but important problem. Accurate estimation of articulatory movements has the potential for significant impact on our understanding of speech production, on our capacity to assess and treat pathologies in a clinical setting, and on speech technologies such as computer aided pronunciation assessment and audio-video synthesis. However, because of the complex and speaker-specific relationship between articulation and acoustics, existing approaches for inversion do not generalize well across speakers. As acquiring speaker-specific kinematic data for training is not feasible in many practical applications, this remains an important and …

A Modular Low-Clearance Wrist Orthosis For Improving Wrist Motion In Children With Cerebral Palsy, Devon Holley, Michelle Johnson, Gerald F. Harris, Scott A. Beardsley

Biomedical Engineering Faculty Research and Publications

Children with Cerebral Palsy (CP) often exhibit impairments in the coordination of the grip and lift phases of arm movements that directly impact their ability to perform activities of daily living (ADLs). The application of assistive robotic therapy to children with spastic hemiplegic CP has shown that augmented movement training can lead to improved functional outcomes and improved arm kinematics. Assistive robotic therapy of the wrist has been shown to help improve motor skills in stroke patients, but the devices employed are often large and obtrusive, focusing on a repeated motion rather than a task-based itinerary. Here, we propose a …

Evaluation Of Upper Extremity Movement Characteristics During Standardized Pediatric Functional Assessment With A Kinect®-Based Markerless Motion Analysis System, Jacob R. Rammer, Joseph J. Krzak, Susan A. Riedel, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

A recently developed and evaluated upper extremity (UE) markerless motion analysis system based on the Microsoft® Kinect® has potential for improving functional assessment of patients with hemiplegic cerebral palsy. 12 typically-developing adolescents ages 12-17 were evaluated using both the Kinect-based system and the Shriners Hospitals for Children Upper Extremity Evaluation (SHUEE), a validated measure of UE motion. The study established population means of UE kinematic parameters for each activity. Statistical correlation analysis was used to identify key kinematic metrics used to develop automatic scoring algorithms. The Kinect motion analysis platform is technically sound and can be applied to standardized task-based …

Multisegmental Foot And Ankle Motion Analysis After Hallux Valgus Surgery, Karl Canseco, Jason T. Long, Thomas Smedberg, Sergey Tarima, Richard Marks, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background: Gait changes in patients with hallux valgus, including altered kinematic and temporal-spatial parameters, have been documented in the literature. Although operative treatment can yield favorable clinical and radiographic results, restoration of normal gait in this population remains unclear. Segmental kinematic changes within the foot and ankle during ambulation after operative correction of hallux valgus have not been reported. The aim of this study was to analyze changes in multisegmental foot and ankle kinematics in patients who underwent operative correction of hallux valgus. Methods: A 15-camera Vicon Motion Analysis System was used to evaluate 24 feet in 19 patients with …

A Model For The Evaluation Of Lower Extremity Kinematics With Integrated Multisegmental Foot Motion, Jason T. Long, Mei Wang, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Background/Purpose

Current models for assessing lower extremity motion during gait benefit from ease of use in the clinical environment. However, underlying assumptions regarding joint location and distal segment motion limit their effectiveness and accuracy. The aim of this study was to develop a model for lower extremity motion analysis, which integrates functional methods for estimating hip joint center (HJC) location and a multisegmental approach to modeling motion of the foot and ankle. The new model is capable of tracking the motion of six segments (pelvis, bilateral thigh, tibia, hindfoot, forefoot, and hallux) during stance and swing.

Methods

Ten healthy young …

Motion Of The Multisegmental Foot In Hallux Valgus, Karl Canseco, Leah Rankine, Jason T. Long, Thomas Smedberg, Richard Marks, Gerald F. Harris

Biomedical Engineering Faculty Research and Publications

Hallux valgus is a common condition characterized by lateral deviation of the large toe and medial deviation of the first metatarsal. While some gait analyses of patients with hallux valgus have been performed using plantar pressures, very little is known about the kinematics of gait in this population. The purpose of this study was to evaluate triplanar kinematics in patients with hallux valgus using a multisegmental foot model. Materials and Methods: A 15-camera Vicon Motion Analysis System was used to evaluate the gait of 38 feet in 33 patients with mild to severe hallux valgus. The Milwaukee foot model was …

Characterization Of Motor Adaptation And Limb Posture Regulation During Arm Reaching Movements Following Stroke, Robert A. Scheidt, Tina M. Stoeckmann

Biomedical Engineering Faculty Research and Publications

Whether attempting to pour water into a handheld glass, or simply trying to hold a young child's hand, many activities of daily living require interaction with unpredictable or uncertain mechanical environments. Here we describe a systems identification study that used a planar manipulandum to characterize how hemiparetic stroke survivors adapt reaching movements to novel mechanical environments. By analyzing trial-by-trial variations in hand path kinematics, we found that stroke survivors are less likely than neurologically-intact subjects to adjust motor commands for upcoming movements based on hand trajectory errors experienced on previous trials. This ability is most significantly compromised in subjects with …