Unconstrained three-dimensional reaching in Rhesus monkeys

To better understand normative behavior for quantitative evaluation of motor recovery after injury, we studied arm movements by non-injured Rhesus monkeys during a food-retrieval task. While seated, monkeys reached, grasped, and retrieved food items. We recorded three-dimensional kinematics and muscle activity, and used inverse dynamics to calculate joint moments due to gravity, segmental interactions, and to the muscles and tissues of the arm. Endpoint paths showed curvature in three dimensions, suggesting that maintaining straight paths was not an important constraint. Joint moments were dominated by gravity. Generalized muscle and interaction moments were less than half of the gravitational moments. The relationships between shoulder and elbow resultant moments were linear during both reach and retrieval. Although both reach and retrieval required elbow flexor moments, an elbow extensor (triceps brachii) was active during both phases. Antagonistic muscles of both the elbow and hand were co-activated during reach and retrieval. Joint behavior could be described by lumped-parameter models analogous to torsional springs at the joints. Minor alterations to joint quasi-stiffness properties, aided by interaction moments, result in reciprocal movements that evolve under the influence of gravity. The strategies identified in monkeys to reach, grasp, and retrieve items will allow the quantification of prehension during recovery after a spinal cord injury and the effectiveness of therapeutic interventions

Advancing Applications of IMUs in Sports Training and Biomechanics.

Miniature inertial measurement units (IMUs) have become popular in the field of biomechanics as an alternative to expensive and cumbersome video-based motion capture (MOCAP). IMUs provide three-axis sensing of angular velocity and linear acceleration in lieu of position data provided by MOCAP. The research presented herein further explores the use of IMUs in five applications for sports training and clinical biomechanics. The first study focuses on the sports of baseball and softball and yields estimates of the release velocity of a pitched ball within 4.6% of MOCAP measurements. The ball angular velocity further distinguishes and quantifies different types of pitches. The second study enables estimates of angular velocity during free-flight based solely on data from an embedded tri-axial accelerometer. Doing so eliminates angular rate gyros, which are often range limited, yet yields angular velocity estimates accurate to within 2%. We further exploit this technique to reveal the rotational stability of rigid bodies in free-flight. The third study extends the use of IMUs to assess the speed of an athlete estimated from a torso-mounted IMU. The speed estimates remain highly correlated with those obtained by MOCAP (r=0.96, slope=0.99) for motions characteristic of explosive sports (e.g., basketball). Moreover, the accurate speed estimation algorithm (mean RMSE=0.35 m/s) does not require data from GPS or magnetometers rendering it valuable and usable in any environment (indoor or outdoor). The remaining studies advance the use of IMU arrays to estimate joint reactions in multibody systems. The fourth study establishes the accuracy of this method using experiments on an instrumented double pendulum. Estimated reaction forces and moments remain within 5.0% and 5.9% RMS respectively of values measured via load cells. The final study addresses the companion need to measure the location of joint centers. A method employing a single IMU yields the center of rotation (CoR) of a spherical joint to within 3 mm as established by a coordinate measuring machine. The simplicity and accuracy of this method may render it attractive for broad use in field, laboratory or clinical applications requiring non-invasive, rapid estimates of joint CoR.PHDMechanical EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/97947/1/ryanmcg_1.pd

Freeform 3D interactions in everyday environments

PhD ThesisPersonal computing is continuously moving away from traditional input using mouse and keyboard, as new input technologies emerge. Recently, natural user interfaces (NUI) have led to interactive systems that are inspired by our physical interactions in the real-world, and focus on enabling dexterous freehand input in 2D or 3D. Another recent trend is Augmented Reality (AR), which follows a similar goal to further reduce the gap between the real and the virtual, but predominately focuses on output, by overlaying virtual information onto a tracked real-world 3D scene. Whilst AR and NUI technologies have been developed for both immersive 3D output as well as seamless 3D input, these have mostly been looked at separately. NUI focuses on sensing the user and enabling new forms of input; AR traditionally focuses on capturing the environment around us and enabling new forms of output that are registered to the real world. The output of NUI systems is mainly presented on a 2D display, while the input technologies for AR experiences, such as data gloves and body-worn motion trackers are often uncomfortable and restricting when interacting in the real world. NUI and AR can be seen as very complimentary, and bringing these two fields together can lead to new user experiences that radically change the way we interact with our everyday environments. The aim of this thesis is to enable real-time, low latency, dexterous input and immersive output without heavily instrumenting the user. The main challenge is to retain and to meaningfully combine the positive qualities that are attributed to both NUI and AR systems. I review work in the intersecting research fields of AR and NUI, and explore freehand 3D interactions with varying degrees of expressiveness, directness and mobility in various physical settings. There a number of technical challenges that arise when designing a mixed NUI/AR system, which I will address is this work: What can we capture, and how? How do we represent the real in the virtual? And how do we physically couple input and output? This is achieved by designing new systems, algorithms, and user experiences that explore the combination of AR and NUI

An Interactive Augmented Reality Alphabet 3-Dimensional Pop-up Book For learning and Recognizing the English Alphabet

This document describes the process developing an Augmented Reality (AR) alphabet book mobile application. Using only an android phone camera, the child could view the superimposed virtual alphabet 3 dimensional objects in a fun and interactive manner using the marker-less physical alphabet book as the interaction tool. The reason behind choosing alphabet teaching as the topic of the book is that the Alphabet knowledge is the core knowledge of any language. It is a jump-start for children to start reading and recognizing words and sentences, thus learning the alphabet is extremely important, for many researchers, emphasizing on how early, child’s education shapes the child’s successful future. Though there are, a great deal of technology based alphabet books; parents still prefer buying the old style physical books or some might use a virtual technology based book application. The problem is that though the physical book possesses many benefits, that our generation and the generations long before us, have experienced, yet from the current generation children’s point of view, they may in fact find it dull and boring. For, it is commonly recognized, that the current generation children are surrounded all around by technology and gadgets, that can make them board, easily distracted, and may refuse to willingly use a plain non-technology book to learn, and if using a virtual application, they will lose the benefits offered by a physical book. Knowing this, the use of Augmented Reality should solve such a problem. For Augmented Reality (AR) is considered the best of both worlds, where, real and virtual objects are combined in the real environment, that will allow the use of both technology based application and a traditional physical book, combining the benefits of both and meeting the child and the parent midway. Although AR technology is not new, its possible potential in education is just beginning to be investigated. The main aim of this research is to develop an interactive 3-Dimentional alphabet pop-up book, and using digital storytelling, to help teach children to learn and recognize the alphabets. The objectives of the study are to enhance the interactions of the alphabet book, by creating an android application that contains animated interactive 3-Dimentional models, interactive sounds, songs and music. Furthermore, to investigate the use of digital storytelling (music, sounds), interactions and animation effect in learning engagement, through using the augmented reality technology. The scope of this project and research is very wide, it includes the 3D modeling, texturing, rigging & animation, book design and content decision research, furthermore, Augmented Reality and Android applicatio

The pathomechanics of shoulder injuries in cricket bowlers

Injury surveillance research has established that over 20 % of cricket injuries are related to the upper limb (Leary & White, 2000; Ranson & Gregory, 2008; Stretch, 2003), with bowlers associated altered rotational joint range of motion (Aginsky et al., 2004, BellJenje & Gray, 2005 and Stuelcken et al., 2008). As the applicability of such observations is limited, the aim of this thesis was to provide researchers with a greater understanding of the pathomechanics of shoulder injuries afflicting cricket bowlers though quantifying associated musculoskeletal adaptations and subsequently through the development and validation of a bowling specific kinematic model, establish the influence these may impart on bowling technique. The use of diagnostic ultrasound within the first experimental study in a cohort of bowlers without a history of shoulder injury, established a high prevalence of supraspinatus (45 %) and subscapularis (50 %) tendon pathology, providing insight into common musculotendinous pathology and adaptations that are indicative of the future potential of injury. Data presented within the second study aimed to first quantify the kinematics of the shoulder during the bowling delivery in relation to humerothoracic motion and, second, the influence of rotation sequence to described humerothoracic motion was investigated. Findings established that whilst the bowling delivery was associated with large variability, future research must acknowledge the contribution of the scapula to shoulder motion. As such, due to the complexity of quantifying shoulder motion during cricket bowling, the following three experimental studies evaluated and developed the CSBT shoulder model through modifying current methods. The mCAST method in conjunction with an acromion cluster, was established to not only reduce resultant RMSE associated with scapula landmarks by up to 0.016 m, but also increase the repeatability and robustness of reconstructing GHJ location using the SCoRE method. The emphasis of the final experimental study was to apply the CSBT shoulder model to establish the contribution of individual rotator cuff muscles to shoulder joint stability and, to identify phases of the bowling delivery which increases the risk of injury. This case study established that during the bowling delivery the shoulder experiences large multi-planar forces placing demand on musculature, in particular supraspinatus and Subscapularis to stabilise the joint. These findings in conjunction with those of the first experimental study, not only identify structures at risk of injury but also establish that for the effective formulation of injury prevention strategies the bowling delivery must be investigated in its entirety.EThOS - Electronic Theses Online ServiceGBUnited Kingdo