Dynamics Simulation Engine is the foundation of the whole system. The engine maintains a realistic dynamics scene in either automatic planning or haptic guided planning. It serves as an off-line verification of the planned motion so that the generated scheme can be 'played' with the engine. In this thesis, we developed a three-dimensional dynamics simulation engine based on an extension of the explicit time-stepping scheme and an application of the differential inclusion process introduced by J. J. Moreau. In the engine, we developed the contact propagation method for a general three-dimensional rigid-body system with multiple unilateral contacts without any bilateral constraints. / In our approach, a sequence of applied forces on the mass center of the workpiece is planned. The applied forces will push the workpiece to get in contact with all the locators. For this purpose, we developed a system with two engines, Motion Planning Engine and Dynamics Simulation Engine. / The goal of Motion Planning Engine is to make the workpiece in contact with all the six locators. Here, the workpiece is initially at an arbitrary place with not contact with any locator. The planning follows a simple scheme of monotonously increase the number of contacts with locators. Here we use a two-step scheme. First, finding the velocity of the workpiece that can approach the new locator while maintaining contacts with old locators. This can be formulated as a linear programming problem. Second, finding the applied force to realize such motion. This step is a central issue in the planning because for the rigid-body model, the solution to multiple frictional contacts is generally indeterministic. One possibility is jamming, that is, the applied force cannot move the workpiece even with less than six contacts. In this thesis, we will give criteria to determine whether the jamming will happen, and we will also derive an algorithm to generate the non-jamming applied force. / The thesis presents an approach to the fixture loading planning problem. That is, to plan the applied forces on the workpiece in order for it to be loaded into a manufacturing fixture. / Liu Tong. / "June 2005." / Adviser: Michael Yu Wang. / Source: Dissertation Abstracts International, Volume: 67-07, Section: B, page: 4067. / Thesis (Ph.D.)--Chinese University of Hong Kong, 2005. / Includes bibliographical references (p. 115-124). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [200-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract in English and Chinese. / School code: 1307.

As a result, this dissertation proposes a novel type of tree climbing robot, named Treebot, which has high maneuverability on trees. The design of Treebot was inspired by arboreal animals such as squirrels and inchworms. The applied extendable continuum maneuvering mechanism has large workspace and high degrees of freedom. It allows Treebot to perform various actions, such as moving between trunk and branches. Treebot is able to grip the surface of trees tightly with a wide range of gripping curvature. It enables Treebot to grip from a big tree trunk to small branches. The special gripping mechanism allows zero energy consumption in static gripping. Although Treebot has high maneuverability, it is compact, lightweight, and only five actuators are used in total. By installing proper equipments, Treebot can assist workers to perform forestry tasks such as inspection and maintenance. It can also be used as a mobile surveillance system to observe behaviors of both ground and arboreal animals. / Climbing robots have become a hot research topic in recent decades. Most research in this area focuses on climbing manmade structures, such as vertical walls, glass windows, and structural frames. Little research has been conducted specifically on climbing natural structures such as trees. The nature of trees and manmade structures is very different. For example, trees have an irregular shape and their surface is not smooth. Some types of trees have soft bark that peels off easily. Hence, most of the climbing methods for manmade structures are not applicable to tree climbing. / In addition to presenting the mechanical design of Treebot, this dissertation also proposes several autonomous tree climbing algorithms. Making a robot climb a tree autonomously is a challenging task, as trees are complex and irregular in shape. However, a certain level of autonomous climbing ability is needed to simplify the operational use of Treebot. The proposed works include autonomous climbing on unknown environment and global path planning on known environment. / Preventing trees from failing is important to protect human life and property in urban areas. Most trees in urban areas require regular maintenance. To reach the upper parts of a tree to perform such maintenance, workers need to climb the tree. However, tree climbing is dangerous, the development of a tree climbing robot is important to assist or replace humans works. / Several robots have been designed to climb trees such as WOODY and RiSE. However, these robots are limited to climbing straight tree trunks, and cannot climb trees that are curved or have branches. As branches and curvature are present in almost all trees, the application of these robots is strongly restricted. / Lam, Tin Lun. / Adviser: Yangsheng Xu. / Source: Dissertation Abstracts International, Volume: 73-03, Section: B, page: . / Thesis (Ph.D.)--Chinese University of Hong Kong, 2010. / Includes bibliographical references (leaves 163-172). / Electronic reproduction. Hong Kong : Chinese University of Hong Kong, [2012] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Electronic reproduction. [Ann Arbor, MI] : ProQuest Information and Learning, [201-] System requirements: Adobe Acrobat Reader. Available via World Wide Web. / Abstract also in Chinese.

Este trabalho tem por objetivo analisar a cinemática de um robô hiperredundante composto por módulos de estrutura paralela e atuadores binários. Cada módulo possui três graus de liberdades, dois graus de liberdade de rotação, com eixos perpendiculares entre si, e um grau de liberdade de translação. Após uma busca das arquiteturas paralelas existentes e relatadas na literatura e uma análise dos graus de liberdades das arquiteturas, foi selecionada a estrutura 3-RPS para o módulo. Essa arquitetura é composta por três cadeias cinemáticas idênticas, cada uma com uma articulação de rotação, uma articulação de translação atuada e uma articulação esférica. Foi desenvolvido um programa computacional para calcular as dimensões ótimas dos módulos considerando as restrições de movimento da junta esférica, as dimensões da base e da plataforma, e o comprimento máximo e mínimo do atuador linear. É realizada uma análise do volume de trabalho do robô hiperredundante composto de três e cinco módulos em série. Como o robô possui atuadores binários o seu volume de trabalho é discreto, consistindo na união de pontos no espaço. Finalmente a cinemática inversa do robô hiper-redundante é calculada e observam-se pequenos erros entre as posições desejadas e as posições alcançadas pelo efetuador do robô hiper-redundante. / This research studies hyper-redundant robots focusing on the kinematics analysis. A hyper-redundant robot was developed based on modules of parallel architecture and binary actuators. Each module has three degrees-of-freedom, two rotational degrees of freedom with perpendicular axis and one translational degree of freedom. After searching for parallel structures existent in the literature and analyzing the degrees of freedom of these structures, the 3-RPS architecture was selected. This architecture is composed by three legs with identical chains, each leg has a rotational joint, a translational actuated joint and a spherical joint. A computational program was developed to calculate the best modules geometry, considering the physical constrains of the spherical joint, the dimensions of the base and of the platform, and the maximum and the minimum values of the binary actuated joint. An analysis of the workspace of the hyper-redundant robot composed by three and five modules in series is performed. Since the robot has discrete actuators its workspace is also discrete, i.e., it is composed by the union of points in space. Finally, the inverse kinematics of the hiper-redundant manipulator is calculated and small errors are observed between the desired position and the real position in space reached by the efectuator.

abstract: Basilisk lizards are often studied for their unique ability to run across the surface of water. Due to the complicated fluid dynamics of this process, the forces applied on the water’s surface cannot be measured using traditional methods. This thesis presents a novel technique of measuring the forces using a fluid dynamic force platform (FDFP), a light, rigid box immersed in water. This platform, along with a motion capture system, can be used to characterize the kinematics and dynamics of a basilisk lizard running on water. This could ultimately lead to robots that can run on water in a similar manner. / Dissertation/Thesis / Masters Thesis Mechanical Engineering 2019

Ankle instability (AI) and fatigue impair neuromuscular control as well as dynamic joint stability of the lower extremity. No one has comprehensively examined the effects of AI and fatigue on neuromechanics of the lower extremity during a functional activity. Deficits associated with AI and fatigue could be additive in increasing the risk for injury in patients with AI. PURPOSE: To examine the interaction of AI and fatigue on lower extremity muscle activity, kinematic, and kinetic patterns during a forward-side jump. METHODS: 25 AI (23.3 ± 1.9 yrs, 176.5 ± 10.5 cm, 70.9 ± 11.4 kg), and 25 matched control subjects (23.7 ± 2.5 yrs, 175.0 ± 10.8 cm, 70.3 ± 12.8 kg) were categorized according to the Foot and Ankle Ability Measure (FAAM) (ADL: 84.3 ± 7.6%, Sport: 63.6 ± 8.6%) and the Modified Ankle Instability Instrument (MAII) (3.7 ± 1.2). Fifty-nine reflective markers were place over anatomical landmarks and eight electromyography (EMG) electrodes were placed on tibialis anterior (TA), peroneus longus (PL), medial gastrocmedius (MG), medial hamstring (MH), vastus lateralis (VL), adductor longus (AL), gluteus medius (GMed), and gluteus maximus (GMax) muscles in the involved leg. Subjects performed five forward-side jumps on a force plate before and after functional fatiguing exercises. To induce fatigue, subjects began 5-min incremental running on a treadmill between 5 and 6 mph. Next, subjects performed 20-second lateral counter movement jumps (CMJ), and 20 vertical CMJs. After each fatigue cycle, subjects performed one max vertical jump. Subjects repeated three exercises until Borg's rating of perceived exertion (RPE) reached 17 and the vertical jump height fell below 80% of their max jump height. Functional analysis of variance (FANOVA) (p < 0.05) was used to evaluate differences (a group by fatigue interaction) between two conditions (pre- vs post-fatigue) in each group (AI and control) for lower-extremity kinematic, kinetic and neuromuscular patterns. Pairwise comparison functions as well as 95% confidence interval (CI) bands were plotted to determine specific differences. If 95% CI bands did not cross the zero line, we considered the difference significant. RESULTS: Compared to the control group, the AI group demonstrated less range of dorsiflexion, knee and hip flexion motions during early phase of landing after fatigue. For sagittal-plane hip kinetics, subjects with AI decreased the hip extension moment while control subjects increased hip extension moments during landing following functional fatiguing exercise. The AI group showed less reduction of anterior-posterior ground reaction force (AP GRF) during transition phase of a forward-side jump after fatigue compared to control subjects. The AI group decreased EMG amplitude of PL, MH, and GMed while increased VL and GMax during landing after fatigue compared to control subjects. CONCLUSION: AI subjects demonstrated greater impairments in neuromechanical control patterns than a matched control group during a sport movement as fatigue progressed. Compared to AI group, control subjects showed a coordinated joint control strategy after fatigue, increasing joint angles from distal (ankle) to proximal (hip) joints by increasing hip extensor moments during landing from a forward-side jump in an attempt to reduce ground impact force. EMG alterations were consistent with patterns observed in injured patients, which may predispose patients to poor positions associated with lower extremity joint injury. These interactions between neuromuscular fatigue and AI may predispose individuals to lower extremity injuries.

The current study examined the effects of three speech conditions (voiced, whispered, mouthed) on articulatory kinematics at the sentence and word level. Participants included 20 adults (10 males, 10 females) with no history of speech, language, or hearing disorders. Participants read aloud six target utterances in the three different speaking conditions while articulatory kinematics were measured using the NDI Wave electromagnetic articulograph. The following articulators were examined: mid tongue, front of tongue, jaw, lower lip, and upper lip. One of the target utterances was chosen for analysis (It's time to shop for two new suits) at the sentence level and then further segmented for more detailed analysis of the word time. Results revealed a number of significant changes between the voiced and mouthed conditions for all articulators at the sentence level. Significant increases in sentence duration, articulatory stroke count, and stroke duration as well as significant decreases in peak stroke speed, stroke distance, and hull volume were found in the mouthed condition at the sentence level when compared to the voiced condition. Peak velocity significantly decreased in the mouthed condition at the word level, but overall the sentence level measures were more sensitive to change. These findings suggest that both laryngeal activation and auditory feedback may be necessary in the production of normally articulate speech, and that the absence of these may account for the significant changes between the voiced and mouthed conditions.

This thesis investigates the potential benefits and challenges of using compliant mechanisms in the design of haptic interfaces. The benefits and challenges are presented with an emphasis on their inherent springback behavior and an active compensation approach. Design criteria for compliant mechanism joint candidates are reviewed and several joints are surveyed. Quantitative calculations of axial stiffness and maximum stress for five candidates are presented. Generalized analytical models of springback force and compensation torque are created to simulate the implementation of each joint candidate in a two degree-of-freedom planar pantograph. We use these models in the development and discussion of an analytical approach to predict the motor torques needed to actively compensate for the effects of springback. This approach relies on virtual work analyses of the haptic pantograph to determine the springback forces, compensation torques, haptic workspace, and available haptic force after compensation. A key to estimating the available haptic force is knowing that the force capability is different depending on the local springback force. If a component of the desired haptic force aligns with the springback force, then the two can work together, thus increasing the maximum magnitude of available haptic force beyond the nominal amount. Analytical and experimental results are presented. A detailed method of implementation is given along with a hardware demonstration of active compensation.

The environmental conditions in the center of the Milky Way galaxy (Central Molecular Zone; CMZ) are much more extreme than in the disk of the galaxy with molecular gas properties similar to those seen in galaxies at z~2. While the CMZ hosts several massive star clusters, the formation of stars from these dense molecular clouds and the feedback of these massive stars on the ISM is not well understood. I present in my thesis a case study of a few regions in the CMZ using VLA continuum and spectral line observations. I explore feedback eects of recent star formation (a young massive stellar cluster) on the surrounding ISM (molecular and ionized gas). Using the kinematic information of molecular and ionized gas, obtained dierent species of spectral lines, I will determine the line of sight geometry of the dierent gas components. I will then establish the relationship of these components to the larger structure of molecular gas in the CMZ.

This dissertation introduces a novel three-dimensional pseudo-rigid-body model (3-D PRBM) for straight cantilever beams with rectangular cross sections. The model is capable of capturing the behavior of the neutral axis of a beam loaded with an arbitrary force end-load. Numerical integration of a system of differential equations yields approximate displacement and orientation of the beam's neutral axis at the free end, and curvatures of the neutral axis at the fixed end. This data was used to develop the 3-D PRBM which consists of two torsional springs connecting two rigid links for a total of 2 degrees of freedom (DOF). The 3-D PRBM parameters that are comparable with existing 2-D model parameters are characteristic radius factor (mean: γ = 0.8322), bending stiffness coefficient (mean: KΘ = 2.5167) and parametric angle coefficient (mean: cΘ = 1.2501). New parameters are introduced in the model in order to capture the spatial behavior of the deflected beam, including two parametric angle coefficients (means: cΨ = 1.0714; cΦ = 1.0087). The model is verified in a few locations using ANSYSTM and its use in the design of compliant mechanisms is illustrated through spatial compliant versions of crank slider and double slider mechanisms.

The George Sound Shear Zone (GSSZ) exposed in Bligh Sound within Fiordland, New Zealand allowed us to reconstruct the kinematics of transpressive flow in >100 km2 of exhumed Cretaceous lower crust. We compare the three-dimensional characteristics of the deformation to theoretical models of transpression that assume steady-state flow in a homogeneous medium. This assumption is rarely the case for shear zones that experience metamorphism during deformation. We determined the three-dimensional kinematics of the GSSZ and evaluated the effects of metamorphism on strain accommodation and structural fabric evolution in the GSSZ to determine if metamorphism is an important parameter that transpressional models should account for. We found that metamorphism aided strain localization within the GSSZ and resulted in a style of structural fabric development that deviates from predictions made by theoretical models. We used foliation and lineation orientation data and field observations to determine GSSZ kinematics. Asymmetric pyroxene σ-porphyroclasts and hornblende fish show top-down-to-the-SW apparent normal shear sense with a sinistral component. The Z-axes of oblate SPO ellipsoids define the vorticity normal section and the moderately WNW-plunging vorticity vector. Foliation deflections relative to the shear zone boundaries yielded a vorticity magnitude (Wk) of ≥0.8. Our kinematic results suggest that the GSSZ records inclined, triclinic transpression with sinistral, top-down-to-the-SW simple shear-dominated flow. We used finite strain analysis and petrographic analysis to determine that metamorphism influences strain accommodation. Finite strain analyses were performed in 3D on 16 samples using the Rf/ɸ, Fry, and Intercept methods to determine the SPO fabric ellipsoids at different stages of deformation. Petrographic analysis was performed to identify metamorphic reactions using syn-kinematic minerals and constrain deformational temperatures using deformation mechanisms of plagioclase. Early deformation formed a ~13 km wide prolate fabric at granulite facies. Deformation later localized into a ~2-4.6 km wide oblate, mylonitic fabric at upper amphibolite facies. This fabric cross-cuts the prolate fabric and is characterized by metamorphic hornblende and biotite produced from retrogressive hydration reactions. Samples with syn-kinematic biotite contain more shear bands and display more grain size reduction of plagioclase than samples without this phase, suggesting these samples may have accommodated more strain. Changes in syn-kinematic metamorphic minerals were accompanied by steepening of stretching lineations and by changes in foliation orientation. Our analyses show that retrogressive hydration metamorphism aided strain localization within a cross-cutting oblate fabric, and the uneven distribution of biotite within this domain potentially influenced along strike variation in strain magnitude and fabric ellipsoid symmetry. Our results highlight the influence of fluid-induced metamorphism on shear zone evolution and call for new transpressional models to incorporate changes in rheology due to syn-kinematic metamorphism.