Dissertations / Theses on the topic 'Walking gait'
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Miao, Shan. "Six legged walking machine gait and design." Thesis, University of Salford, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.300830.
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Hughes-Oliver, Cherice. "Walking Speed, Gait Asymmetry, and Motor Variability." Thesis, Virginia Tech, 2018. http://hdl.handle.net/10919/82551.
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Study design is among the most fundamental factors influencing collection and interpretation of data. The purpose of this study is to understand the effect of design choices by evaluating gait mechanics in healthy control participants using three primary objectives: 1) determine the repeatability of marker placement, 2) determine the effect of set versus self-selected walking speed, and 3) examine the correlation between gait asymmetry and motor variability.
Ten and fifty-one healthy control participants were recruited for aim 1 and aims 2/3, respectively. Reflective markers were placed on lower-extremity bony landmarks and participants walked on an instrumented treadmill while 3D motion capture data was collected. For aim 1, this procedure was repeated at two time points 30 minutes apart. For aims 2 and 3, participants completed set and self-selected speed trials. JMP Pro 13 was used to compare joint kinetics and gait kinematics for all aims.
Marker placement was repeatable between time points. Participants walked slower in the self-selected walking speed trial, which resulted in both kinematic and kinetic gait mechanics alterations. Gait asymmetry was significantly correlated with motor variability for both spatial and temporal measures.
Current study findings reiterated the importance of walking speed when evaluating gait symmetry, joint kinetics, and kinematics. The decision regarding whether to utilize a set or self-selected speed condition within a study design should be made based on whether the measures of interest are independent of walking speed. Gait asymmetry and motor variability are related and should not be treated as independent components of gait.Master of Science
This study aims to evaluate gait mechanics in healthy young adults by evaluating the impact of multiple study design choices and relationships between different aspects of gait (walking). Loading and movement walking data was collected from a total of sixty-one participants. This data was then used to calculate several measures of gait including symmetry between limbs, joint ranges of motion, and variability of movement. The potential impact of study design choices including setting walking speed for all participants and evaluating loading asymmetry and movement variability independently are discussed based on the findings of the current study.
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Nicolaou, Maria. "Gait adaptations to transverse slopes." Thesis, McGill University, 2001. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=32931.
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The purpose of the study was to identify the lower limb kinematic adaptations made in normal gait to accommodate to static transverse slopes. Five male subjects were asked to walk along a platform at 0%, 5% and 10% slope. Kinematic data for the ankle, knee and hip were collected at 60Hz using the Ultratrak RTM (Polhemus Inc., Burlington, VT, USA) electromagnetic tracking system. Results indicated that significant (p < 0.05) joint angle changes occurred in both the uphill (UH) and downhill (DH) lower limbs. The adaptations served as compensatory changes to functionally shorten the UH limb and lengthen the DH limb.
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Norberg, Jaclyn D. "Biomechanical Analysis of Race Walking Compared to Normal Walking and Running Gait." UKnowledge, 2015. http://uknowledge.uky.edu/khp_etds/20.
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Human locomotion is phenomenon that is extraordinarily complex. It is evident that a complete description of locomotion involves consideration of kinematics, kinetics, and muscle activity of the extremities in all of their various movements. Race walking (RW) is a form of upright locomotion that differs from normal walking and running by its form dictated by the International Amateur Athletics Federation (IAAF). Despite the similarities to both normal walking (NW) and running (RU), RW has not been the subject of equally intensive investigations.
This study explores the comprehensive biomechanics of race walking and how it compares to NW and RU. A quantitative approach was used to evaluate kinematic, kinetic and muscle activity variables between race walking and both normal walking and running. A cross-sectional, laboratory design was used on 15 recreationally competitive race walkers to evaluate these variables.
Based on the results of this study, RW is an intermediate gait between NW and RU that has characteristics of both gaits, but is still a unique gait in itself. While there are differences between RW and both RU and NW, some of the expected differences between RW and the two gaits did not occur. Significantly greater frontal plane pelvis-trunk joint range of motion and sagittal plane peak hip flexor and extensor moments, hip joint range of motion and rectus femoris muscle activity contribute to the significant differences in both RW and NW, and RW and RU.
Significant differences between RW and RU showed that RU requires more contribution from the trunk, pelvis and lower extremities kinematically and kinetically, as well as increased muscle activation, to execute the motion than RW. Conversely, RW requires more contribution from these variables than NW does, but in not as great a capacity as RU compared to RW. In spite of these findings, there were some variables that had no significant differences between RW and RU. This suggests that injuries during RW are similar to those during RU, but may not occur as frequently.
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Harata, Yuji, Fumihiko Asano, Kouichi Taji, and Yoji Uno. "Parametric Excitation Based Gait Generation for Ornithoid Walking." IEEE, 2008. http://hdl.handle.net/2237/12104.
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Dixon, Philippe. "Gait dynamics on a cross-slope walking surface." Thesis, McGill University, 2008. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=112616.
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Though the biomechanics of level walking have been studied extensively, the adaptations required for cross-slope locomotion are still largely unknown despite being a common terrain characteristic. The goals of this thesis were to determine (1) ground reaction forces (GRF) and moments (GRM), (2) lower-limb kinematics, and (3) lower-limb joint reaction forces (JRF) and moments (JRM) during level and cross-slope walking. Statistical analyses were made across limbs (down-slope (DS) and up-slope (US)) and across slope condition (level (0°) and cross-slope (6°)) (2X2 ANOVA). Ten healthy male volunteers performed several barefoot walking trials. The lower-limbs responded asymmetrically to the cross-slope condition by substantially changing (1) the medio-lateral GRF, (2) the sagittal and frontal plane kinematics as well as step-width, and (3) the medio-lateral JRF and frontal plane JRM. The modest cross-slope induced important asymmetrical changes in locomotor patterns and may represent a substantial physical obstacle to populations with restricted mobility.
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Dall'Alpi, Daniele. "Gait generation for a six-legged walking machine." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018.
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This thesis focuses on the study of a six-legged walking machine. It consists of a chassis and six legs with three revolute joints each. Instead of a feet, each leg features a wheel, so that it is not only capable of walking but also driving. Furthermore, the robot is equipped with a 5-DOF arm and a gripper. The robot uses an Arduino platform for low-level control of the drives and an x86-64 computer for high-level tasks such as flow control, image processing, navigation or obstacle recognition.
The aim of this work is to implement a gait generation algorithm in a six-legged walking machine and simulate the behaviour of the system. First of all, a thorough survey of literature considering static gait of multi-legged walking machines, planning-based and reactive controllers needs to be conducted. After deciding on a gait generation approach, the corresponding algorithms will be adapted to the specifications of the robot and implemented for simulation.
A kinematic model of the robot is derived. A dynamic model is not needed since we focus on gait planning for statically stable walking.
There are two possible modes of operation: remote controlled and autonomous. In the former mode, the robot is controlled from a base station with a gamepad and movement commands are transmitted to the mobile robot. We think that the easiest way to control the robot is to assign the curvature of the desired path (turning radius) and the orientation of the robot with respect to the motion direction (crab angle). In fact, only two inputs are needed in order to perform any general trajectory.
In order to achieve the best result for the gait planning, some different procedures are developed. Their performances are compared considering both the stability of the motion and the computation time.
Finally, once the gait is generated, inverse kinematics is used to determine motors motion law.
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Zhang, S. J. "Multi-legged walking machines : mechanics, design and gait." Thesis, University of Salford, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262054.
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Charles, William G. "Dynamic walking models to understand asymmetric gait characteristics." Thesis, Swansea University, 2018. https://cronfa.swan.ac.uk/Record/cronfa48133.
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Passive dynamic walking models remarkably predict gait behaviour such as walk-run transition speeds, preferred step length, stride frequencies and - with the inclusion of springs - ground reaction forces. Muscular or neurological conditions may lead to asymmetric walking characteristics that, in turn, come with long term health risks. Gait analysis may be used to understand an individual patient's conditions to help rehabilitate them. However, people adapt their kinematic and kinetic walking patterns so it can be hard to distinguish the effects of gait alterations such as inertial imbalance or injury. In this thesis a compass walking model with no active controllers is explored to understand the dynamics of gait. To help us interpret the effects of mass imbalance with a prosthetic foot or orthotic device, asymmetric loading conditions are investigated. A simple spring-mass walking model is used to explore the effects of altered touch-down angles and effective leg stiffness to see if these are used as strategies to alter the characteristics of gait. Results show that an asymmetric touch-down angle alters step length while retaining a symmetric stance time. A hybrid model is then derived with springs to emulate human-like ground reaction forces and asymmetric inertial loading of the legs. Results support previous research that push-off from the trailing leg propels the leg mass more than the body mass. Higher rates of joint forces, larger step lengths and a longer stance time on the residual limb may be due to the prosthetic leg stiffness or the higher location of centre-of-mass. These results help us understand how the dynamic components affect gait characteristics such as step length, stance time and walking speeds. This work is motivated by the needs of persons with disabilities and by the desire to understand human walking.
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Richards, James David. "Gait analysis under different testing conditions and their effect on non-pathological and intermittent claudication gait." Thesis, Glasgow Caledonian University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.267083.
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Menz, Hylton Physiology UNSW. "Walking stability in young, old and neuropathic subjects." Awarded by:University of New South Wales. Physiology, 2002. http://handle.unsw.edu.au/1959.4/18637.
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This thesis investigates walking patterns in healthy young people and in people with an increased risk of falling, and determines the physiological contributions to walking stability. First, a review of the relevant literature on techniques for assessing walking stability, age-related changes in balance and gait, and the contributions of vision, vestibular function, peripheral sensation and strength was undertaken. In response to a critical analysis of these findings, a new technique and protocol for the assessment of walking stability was developed. This involved measuring and analysing head and pelvis accelerations while subjects walked on a level surface and an irregular surface. Gait patterns were studied in 30 young healthy subjects and two groups known to be at increased risk of falling - 100 subjects over the age of 75, and 30 subjects with diabetic peripheral neuropathy. A series of vision, sensation, strength, reaction time and balance tests were also undertaken to identify subjects??? physiological abilities and risk of falls. Acceleration patterns of the head and pelvis differed according to physiological risk of falling, particularly when walking on the irregular surface. Those with a high risk of falling walked with a reduced velocity, cadence and step length, and exhibited less rhythmic acceleration patterns at the head and pelvis. Gait patterns were significantly associated with leg strength, peripheral sensation and reaction time. It is concluded that subjects with a high physiological risk of falling exhibit characteristic patterns of walking that indicate an impaired ability to control the movement of the pelvis and head, which may predispose to loss of balance.
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Gormley, John Patrick. "An examination of the duration of gait initiation." Thesis, University of Ulster, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339306.
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Marmar, Zuheir. "The effects of prosthetic alignment on the stability of the knee in above knee amputees." Thesis, University of Strathclyde, 1993. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=21354.
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The components and alignment of a prosthesis have a large influence on the gait of an above knee amputee. The present criteria for determining the optimum alignment are mainly subjective, based on visual observation of the amputee's gait and by considering his/her comments. These comments however, are not always helpful. It has been reported that a range of alignments is acceptable to the patient and to the prosthetist, and it is believed that the optimum alignment can be selected from the range of acceptable alignments using biomechanical analysis. The socket is an important component in an above knee prosthesis and can affect the gait of the amputee. While the conventional socket is the quadrilateral, several problems have been reported with this type of socket. These include instability in the coronal plane, discomfort and restriction of the stump muscles causing limitations in the function of the prosthesis. In an attempt to overcome these problems the ischial containment (IC) socket was introduced in 1985. The biomechanical characteristics of the IC socket have, however, not been objectively assessed and compared with those of the quadrilateral socket. In this study, the effect of alignment adjustments on the gait variables for eight above knee amputees wearing quadrilateral sockets was investigated. Three of these amputees were also tested wearing IC sockets. The alignment of the prosthesis was systematically changed at the ankle, knee and socket. The primary aim of this project was therefore, to systematically vary the alignment of the prosthesis and to study the effects on the gait, and to compare the performance of amputees wearing IC and quadrilateral sockets. The ultimate goal of this research work is to provide a method for the determination of the optimum alignment from a range of acceptable alignments. A socket axis locator and a coordinate measuring system were used for measuring the prosthetic alignment accurately. Three TV cameras and two Kistler force plates were operated simultaneously and synchronously at a rate I of 50 Hz to acquire the displacements of the body segments and the ground reaction forces. All angular movements at the joints, moments and the temporal-distance parameters were calculated for both the prosthetic and the sound legs of the amputees, and for the right and left legs of ten normal subjects. The movement of the upper body was also recorded. Computer programs were developed to calculate and graphically present the above parameters in three dimensions. It was found that alignment changes affected the gait parameters of the whole body. At the prosthetic joints, certain changes in the alignment of the prosthesis resulted in specific alterations in the gait pattern. These effects were repeatable. The anterior-posterior (AP) joints moments and the fore-and-aft ground reaction force were found to be the most sensitive variables to alignment changes. The trunk rotations in the AP and medio-lateral planes, and the torso rotation in the transverse plane were also found to be sensitive to alignment changes, and the trunk was the main compensating element for any misalignment. At the sound side, the alignment changes resulted in noticeable changes in the AP joints moments and fore-and-aft ground reaction force. In the coronal and transverse planes, changes in the gait patterns that were analysed were not always consistent. These changes mainly depend on the method of compensation which is adopted by the patient. The IC socket showed improvements in the patient's performance in terms of higher speed of walking, comfort, improved symmetry in the two legs and the gait parameters are more comparable with those of normals.
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Arnold, Mark Andrew. "Finite element analysis of ankle foot orthoses." Thesis, University of Southampton, 1999. https://eprints.soton.ac.uk/393597/.
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Muratagic, Haris. "Passive Symmetry in Dynamic Systems and Walking." Scholar Commons, 2015. http://scholarcommons.usf.edu/etd/5998.
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The ubiquitous nature of symmetry lends itself to be taken for granted, however the breath of research on symmetry encompasses several disciplines. In engineering, studies centered on symmetry often address issues in dynamic systems theory, robotics, and gait rehabilitation. This thesis presents findings on two specific topics dealing with passively induced symmetry; dissimilar rotating systems and human gait. Past studies on passive symmetry in dynamic systems often incorporate physical coupling or a controller. This thesis presents a technique to passively induce symmetry between two dissimilar systems that are not physically connected. This work also presents a human gait study consisting of several elements that merge to provide a unique look at how walking symmetry and altered physical parameters (leg length and added weight) of the lower limbs are related.
One aspect of this thesis shows the successful development of a general method to induce synchronization between any two dissimilar, uncoupled, rotating systems given the same degrees of freedom, initial angular dynamics, and applied torque. This method is validated with a simulation and subsequent comparison with two physical experiments. The results are in agreement, with slight variations due to the friction and damping of the physical systems. This is further expanded to include the induced symmetry of two systems that experience an external collision. Due to the highly non-linear nature of such systems, an analytical solution was not found; instead a numerical solution is presented that resulted in partial symmetry between systems.
The gait study demonstrated that weighted walking and altered leg length have both independent and combined spatio-temporal effects on lower limb symmetry. While altered leg length alone resulted in higher gait asymmetry, the combination of the two physical changes increases this asymmetry to affect the same limb. This study also showed that cognitive and physically distracted walking does not have an added effect to the gait symmetry with passive physical changes. In addition, this study was able to demonstrate that the arm swinging that occurs during natural walking does not significantly alter spatial or temporal gait parameters.
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Tong, Kai-Yu. "Artificial neural network control of FES gait using virtual kinematic sensors." Thesis, University of Strathclyde, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.248500.
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Opila, K. A. "Impulse characteristics and upper limb loadings of aided gait." Thesis, University of Strathclyde, 1985. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.372120.
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Srinivasan, Sujatha. "Low-dimensional modeling and analysis of human gait with application to the gait of transtibial prosthesis users." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1179865923.
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Jackowski, Zachary John. "Design, construction, and experiments with a compass gait walking robot." Thesis, Massachusetts Institute of Technology, 2011. http://hdl.handle.net/1721.1/67617.
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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2011.Cataloged from PDF version of thesis.
Includes bibliographical references (p. 91-93).
In recent years a number of new computational techniques for the control of nonlinear and underactuated systems have been developed and tested largely in theory and simulation. In order to better understand how these new tools are applied to real systems and to expose areas where the theory is lacking testing on a physical model system is necessary. In this thesis a human scale, free walking, planar bipedal walking robot is designed and several of these new control techniques are tested. These include system identification via simulation error optimization, simulation based LQR-Trees, and transverse stabilization of trajectories. Emphasis is put on the topics of designing highly dynamic robots, practical considerations in implementation of these advanced control strategies, and exploring where these techniques need additional development.
by Zachary J Jackowski.
S.M.
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Luo, Jingya Lauren. "Smart shoe force sensor development and analysis for walking gait." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/119946.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references (page 31).
Foot contact forces are imperative to gait analysis for uses such as elderly rehabilitation and athletic training. Previously developed methods for legged locomotion force detection involved convoluted sensing systems and significant external equipment. This thesis builds upon previous developed smart shoe sensors adapted from the MIT Cheetah robot using pressure sensors embedded in urethane rubber, Smooth-On's Vytaflex® 20. Past work developed accurate material models in Abaqus CAE to simulate foot contacts for compression and shear. This thesis builds upon the FEA models for two sensor sizes to create a simple model to measure torque and contact angle given force measured by the sensor. Using experiments with physical footpads on a CNC mill verified by simulations from Abaqus FEA, we derived models for contact angles between 0 to 15 degrees and rolling movement from -7 to 7 degrees at various compressions. Models successfully derive relationships between roll and contact angle versus force. These models can be used as a jumping point for data analysis using the smart shoe sensor.
by Jingya (Lauren) Luo.
S.B.
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Krajíček, Lukáš. "Implementace řídicích členů pro mobilní kráčivý robot." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230071.
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This diploma thesis deals with design and implementation of the controllers of a mobile walking robot. The advantage of these controllers are their kinematics and geometrics independent representation, which allow to use them for different robot types and tasks. In this thesis the contact controller is designed, which minimizes residual forces and torques at the robot's center of gravity, and thereby stabilize robot's body. Next the thesis deals with a posture controller, which maximizes a heuristic posture measure to optimize posture of robot body. Because of this optimization, legs are moved away from their limits and therefore they have more working space for next move. Implementation of the chosen solution is made on the robot's MATLAB mathematical model. Controllers are composed into a control basis, that allows to solve general control tasks by simultaneous combination of contained controllers. The algorithm was created for that simultaneous activation and its operation was explained on flow charts.
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Zhou, Lei. "Nordic Pole Walking, Gait Pattern and Postural Control in Parkinson Disease." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/35178.
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Background: Gait impairments and postural deficits are very common in people with Parkinson Disease (PD), and also highly associated with fall risk and functional decline. Some evidence showed that in older adults, Nordic Walking (NW) could slow the progression of some gait impairments and increasing stride length and gait speed. Moreover, previous studies suggested that gait disturbances in PD are associated with less automatic gait performances and therefore gait requires more attention, as it is essential for regulation of postural balance. Further, research of this fact has very minimally been examined in PD population.
Purpose: The purpose of this study is to investigate whether Nordic walking can improve gait pattern in individual with PD after a 6-week training program, as well as determine the effect of performing a cognitive task while walking with and without the poles on gait characteristics.
Methods: Gait spatial temporal and kinetics data was collected with and without poles in 12 adults with PD (age: 61.58±11.7 years; 9 male, 3 female; Hoehn and Yahr scale 1-3 stage; UPDRS III average: 11; the year of diagnosis: 6.72 years). Participants performed six 5m walking trials; 3 with poles and 3 without after 6-week training. Participants also performed four 90 seconds walking trials on a 25m pathway in four different conditions: NP (no poles) and no cognitive task, NW (Nordic walking) and no cognitive task, NP and a cognitive task, NW and a cognitive task. For this latter part of the experiment, gait characteristics and trunk kinematics were quantified by using a 6 inertial sensor accelerometry system (APDM, Oregon, USA). As for the 5m tasks, gait spatial temporal and kinetics were collected with an eight cameras 3-dimensional motion capture system (Vicon, Oxford, UK) and 2 force platforms (Kistler, Winterthur, Switzerland). All variables were assessed using paired t-test to compare NW to conventional walking and two-way ANOVA to compare cognitive and pole conditions.
Results: When comparing NW to NP, the results showed significantly longer stride length, and larger single support time. The data also showed larger knee power generation during mid-stance as well as decreased power absorption at the knee during swing. Moreover, when assessing the effect of performing a cognitive task on gait, gait speed and cadence in both normal walking and Nordic pole walking was significant smaller when performing the cognitive task. The trunk frontal range of motion (ROM) and velocity were smaller compared NW to NP. When adding cognitive tasks, trunk frontal ROM and velocity were significantly smaller.
Conclusions: Based on the results, 16 self-directed sessions of NW can help improve certain gait spatial-temporal characteristics as well as some aspect of the gait pattern kinetics, especially at the knee. Moreover it seems that a 16 sessions (45mintues per session) or even longer practice period is necessary for NW beginner, in order to gain perfect technique and restore gait to a more normal pattern than novice.
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Shannon, Colleen Elizabeth. "Recurrent Gait of Anthropomorphic, Bipedal Walkers." Thesis, Virginia Tech, 2003. http://hdl.handle.net/10919/33322.
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This thesis explores the dynamics of two bipedal, passive-walker models that are free to move in a three-dimensional environment. Specifically, two rigid-bodied walkers that can sustain anthropomorphic gait down an inclined plane with gravity being the only source of energy were studied using standard dynamical systems methods. This includes calculating the stability of periodic orbits and varying the system parameter to create bifurcation diagrams and to address the persistence of a periodic solution under specific parameter variations. These periodic orbits are found by implementing the Newton-Raphson root solving scheme. The dynamical systems associated with these periodic orbits are not completely smooth. Instead, they include discontinuities, such as those produced due to forces at foot contact points and during knee hyper-extension. These discontinuities are addressed in the stability calculations through appropriate discontinuity mappings.
The difference between the two walker models is the number of degrees of freedom (DOF) at the hip. Humans possess three DOF at each hip joint, one DOF at each knee joint, and at least two DOF at each ankle joint. The first walker model studied had revolute joints at the hips and knees and completely locked ankles. To make the walking motion more anthropomorphic, additional degrees of freedom were added to the hip. Specifically, the second walker model has ball joints at the hips.
Two control algorithms are used for controlling the local stability of periodic motions for both walker models. The methods, reference and delay feedback control, rely on the presence of discontinuities in the system. Moreover, it is possible to predict the effects of the control strategy based entirely on information from the uncontrolled system. Control is applied to both passive walker models to try and stabilize an unstable periodic gait by making small, discrete, changes in the foot orientation during gait. Results show that both methods are successful in stabilizing an unstable walking motion for a 3D model with one DOF in each hip and to reduce the instability of the walking motions for the model having more mobility in the hip joints.Master of Science
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Karalarli, Emre. "Intelligent Gait Control Of A Multilegged Robot Used In Rescue Operations." Master's thesis, METU, 2003. http://etd.lib.metu.edu.tr/upload/1056860/index.pdf.
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In this thesis work an intelligent controller based on a gait synthesizer for a hexapod robot used in rescue operations is developed. The gait synthesizer draws decisions from insect-inspired gait patterns to the changing needs of the terrain and that of rescue. It is composed of three modules responsible for selecting a new gait, evaluating the current gait, and modifying the recommended gait according to the internal reinforcements of past time steps. A Fuzzy Logic Controller is implemented in selecting the new gaits.
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Jin, Li. "KINEMATIC AND KINETIC ANALYSIS OF WALKING AND RUNNING ACROSS SPEEDS AND TRANSITIONS BETWEEN LOCOMOTION STATES." Thesis, University of Oregon, 2018. http://hdl.handle.net/1794/23912.
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DISSERTATION ABSTRACT
Li Jin
Doctor of Philosophy
Department of Human Physiology
March 2018
Title: Kinematic and Kinetic Analysis of Walking and Running across Speeds and Transitions between Locomotion States
Walking and running are general locomotion activities for human beings. Basic gait patterns and whole body center of mass (COM) dynamic patterns are distinctly different between them. Lower extremity joint mechanics patterns could reflect musculoskeletal coordination characteristics. Change of locomotion tasks and speeds can affect lower extremity joint kinematic and kinetic characteristics, and progression of age may also affect these characteristics. Little is known about change of locomotion tasks and speeds effects on lower extremity joint level kinetic characteristics, and whether there is a connection between COM system and lower extremity system. To address this, twenty healthy subjects were recruited to participate in a series of treadmill tests, including walking (0.8 – 2.0 m/s, with 0.2 m/s intervals), running (1.8 – 3.8 m/s, with 0.4 m/s intervals) and gait mode transition from walking to running, and from running to walking (between 1.8 – 2.4 m/s, 0.1 m/s2). Three-dimensional kinematic and kinetic data were collected in all locomotion tests and used to calculate and analyze outcome variables for lower extremity joints and the COM system across different conditions. Results indicate that change of locomotion speeds significantly affect joint level kinetic characteristics within both walking and running locomotion states. Different locomotion task demands (walking vs. running) require fundamental alteration of lower extremity joint level kinetic patterns, even at the same locomotion speed. Progression of age also affects lower extremity joint level kinematic and kinetic patterns in walking and running across speeds. Additionally, stance phase an energy generation and transfer phenomenon occurred between the distal and proximal joints of the lower extremity in both walk-to-run and run-to-walk transitions. Lastly, a connection exists between whole body COM oscillation patterns and lower extremity joint level kinetic characteristics in running. These findings serve to further clarify the mechanisms involved in change of locomotion tasks and speeds effects on lower extremity joint kinetic patterns, and further establish a connection between the COM system and the lower extremity system. These findings may be beneficial for future foot-ankle assistive device development, potential optimization of gait efficiency and performance enhancement.
This dissertation includes previously published and unpublished coauthored material.
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Chiu, Shiu-Ling, and Shiu-Ling Chiu. "Assessing Inter-joint Coordination during Walking." Thesis, University of Oregon, 2012. http://hdl.handle.net/1794/12543.
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Coordination indicates the ability to assemble and maintain a series of proper relations between joints or segments during motions. In Dynamical Systems Theory (DST), movement patterns are results of a synergistic organization of the neuromuscular system based on the constraints of anatomical structures, environmental factors, and movement tasks. Human gait requires the high level of neuromuscular control to regulate the initiation, intensity and adaptability of movements. To better understand how the neuromuscular system organizes and coordinates movements during walking, examination of single joint kinematics and kinetics alone may not be sufficient. Studying inter-joint coordination will provide insights into the essential timing and sequencing of neuromuscular control over biomechanical degrees of freedom, and the variability of inter-joint coordination would reflect the adaptability of such control.
Previous studies assessing inter-joint coordination were mainly focused on neurological deficiencies, such as stroke or cerebral palsy. However, information on how inter-joint coordination is modulated with different constraints, such as walking speeds, aging, brain injury or joint dysfunctions, are limited. This knowledge could help us in identifying the potential risks during walking and improve the performance of individuals with movement impairments. The purpose of the present study was to investigate the properties of inter-joint coordination pattern and variability during walking with different levels of neuromuscular system perturbations using a DST approach, including an overall neuromuscular systemic degeneration, a direct insult to the brain, and a joint disease.
We found that aging seemed to reduce the pattern adaptability of neuromuscular control. Isolated brain injury and joint disease altered the coordination pattern and exaggerated the variability, indicating a poor neuromuscular control. To improve gait performances for different populations, clinical rehabilitation should be carefully designed as different levels of neuromuscular system constraints would lead to different needs for facilitating appropriate coordinative movement.
This dissertation includes both previously published/unpublished and coauthored material.
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Muaaz, Muhammad. "Inuence of Walking Surfaces and Speeds on Accelerometer-Based Gait Recognition." Thesis, KTH, Skolan för informations- och kommunikationsteknik (ICT), 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-102364.
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Identification and verification first line of defence of every secure system. Due to the advancement of technology and miniaturization, the use of mobile devices is highly increased since last decade. Nowadays, mobile phones are more powerful than the computers of early days of last decade. Today, mobile phones hold a lot of personal and sensitive data, which must be protected using most reliable, robust, convenient and cost effective authentication mechanisms. Biometric authentication is one of the three methods of identi cation. Gait authentication is one type of biometric authentication that operates on behavioral characteristics of human beings. There are dierent approaches in gait authentication. In this thesis, we have used wearable sensor based approach and for this purpose Google G1 smart phone is used to collect gait data. This thesis is an attempt tond out the inuence of dierent walking speeds (slow, normal and fast) and surfaces (at carpeted, grass, gravel and inclined) on gait recognition. This gait data is collected from 48 subjects for these six dierent walk settings in two sessions on dierent days to measure same day and cross day performance. Later, dierent mathematical and machine learning concepts are used to analyze recorded data and extract typical gait cycle for each subject. Dierent evaluations are conducted to nd out best parameter settings of these methods. For different walking speeds, same-day results vary between 14% to 29%, and cross day results vary between 29% and 35%. Similarly, for different walking surfaces, same-day results vary between 9.78% to 39%, and cross day results vary between 28% to 42%. Results of tests conducted for one walk setting clearly reects that slight change in parameters also inuences the results.
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Heusel-Gillig, L., A. Nogi, and Courtney D. Hall. "Suggested Guidelines for Backwards Walking Speed: Scoring the Functional Gait Assessment." Digital Commons @ East Tennessee State University, 2018. https://dc.etsu.edu/etsu-works/2709.
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Huerta, Alyda. "Variable stiffness orthosis for gait normalization in patients with toe walking." Thesis, Massachusetts Institute of Technology, 2019. https://hdl.handle.net/1721.1/123288.
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Thesis: S.B., Massachusetts Institute of Technology, Department of Mechanical Engineering, 2019Cataloged from PDF version of thesis.
Includes bibliographical references (pages 33-34).
Duchenne muscular dystrophy (DMD) is an X-linked recessive neuro-muscular disorder that causes progressive muscle degeneration. DMD patients tend to walk on their tip toes because of their weak calf muscles and currently do not have many options for managing the fatigue induced by supporting most of the foot strike impact with the ball of their feet. Patients with Idiopathic Toe Walking (ITW) suffer from similar symptoms and lack of physical support when walking. The addition of external heel support through an orthosis attached on the exterior of the heel of the shoe may help reduce this fatigue and correct the tip toe gait of DMD and ITW patients, enabling them to walk for longer distances unassisted. In order to study the effect of additional heel support with an orthosis, a custom orthosis with variable stiffness cushioning was designed. A healthy subject walked with simulated tip toe walking observed in DMD and ITW patients on a treadmill for three thirty-second trials, each with a cushioning material of rubber, gel, or foam added to the orthosis. The force on the foot, calf muscle activity, and video were recorded. Controls of "normal" walking and tip toe walking without prototypes were used for baseline comparisons. Material firmness and Young's modulus were measured for each of the materials with a compression test using a texture analyzer. There was a significant decrease in muscle activity from the tip toe control with the foam orthosis for both feet and for all orthosis materials for the right foot. There was also a significant improvement in heel-to-ball force ratios for all orthosis materials compared to the tip toe control. There was no observed correlation between material firmness and Young's modulus with muscle activity or heel-to-ball force ratio. The gait analysis from the video showed a gait appearance closer to that of the normal control than the tip toe control with the orthoses..
by Alyda Huerta.
S.B.
S.B. Massachusetts Institute of Technology, Department of Mechanical Engineering
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Michaels, Nathaniel I. "A Modular Robotic AFO for detecting phase changes during Walking Gait." Digital WPI, 2020. https://digitalcommons.wpi.edu/etd-dissertations/599.
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The focus of this paper is on the development of a modular AFO (Ankle Foot Orthosis) subsystem for the greater L.A.R.R.E (Legged Anthropomorphic Robotic Rehab Exoskeleton) Exoskeleton. The main role of the AFO device is in the role of medical rehabilitation, by providing passively-powered dorsiexion support to the user's ankle in order to prevent foot drop. It is able to accomplish this role through the use of a torsional spring attached to the ankle joint. Additionally, the AFO must also be able to provide sensory-feedback to the greater L.A.R.R.E system in order to help control walking gait. It can detect the orientation of the ankle through the use of both a potentiometer and IMU attached at the ankle joint, and it can detect which part of the foot is in contact with the ground through a specially-designed tactile sensor embedded within the sole of the AFO. This sensor consists of Force-Sensing Resistor sensors encased within a polyurethane rubber mold to provide protection from wear and tear as well as provide a rough surface to keep the device from slipping. The development of this "Sole-Sensor" was fairly extensive, with multiple iterations of the sensor being developed over the course of the project. It was found that Sole-Sensor works best when the resin geometry is shaped in such a way that it concentrates all forces applied on it directly above the FSRs. The development of a working Sole-Sensor subsystem allowed a proper test of the Right-foot AFO system within a VICON Motion-Capture room to test Foot-position detection and Center-of-Pressure point tracking. Translating the AFO CoP point into the VICON Lab's "World Frame" and comparing it to the independently calculated Force-Plate CoP point shows a maximum position displacement of +/- 3cm along the AFO's X-axis and +/- 5cm along the Y-axis.
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MILLER, KIMBERLY MAXINE. "COMPUTER SIMULATION AND VALIDATION OF HUMAN WALKING ON STILTS." University of Cincinnati / OhioLINK, 2003. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1054915838.
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Flanagan, John Randall. "Kinematic properties of human walking and running movements at different treadmill velocities." Thesis, McGill University, 1986. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66164.
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Wills, Eric David. "Gait animation and analysis for biomechanically-articulated skeletons /." Connect to title online (Scholars' Bank) Connect to title online (ProQuest), 2008. http://hdl.handle.net/1794/7508.
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Thesis (Ph. D.)--University of Oregon, 2008.Typescript. Includes vita and abstract. Includes bibliographical references (leaves 281-287). Also available online in Scholars' Bank; and in ProQuest, free to University of Oregon users.
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Chan, Herman King Yeung. "Machine learning and statistical approaches to support gait analysis." Thesis, Ulster University, 2014. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.646039.
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Acevedo, Navine N. "Effects of shoe geometry on kinematics and kinetics of gait." To read this dissertation, search for it in Kinesiology Publications database, 2004. http://www.oregonpdf.org.
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Xiao, Ming. "Computer simulation of human walking model sensitivity and application to stroke gait /." Access to citation, abstract and download form provided by ProQuest Information and Learning Company; downloadable PDF file, 129 p, 2009. http://proquest.umi.com/pqdweb?did=1885693291&sid=2&Fmt=2&clientId=8331&RQT=309&VName=PQD.
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Macleod, Catherine A. "Development of a reflexive control system for gait using human walking data." Thesis, University of Strathclyde, 2015. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=25804.
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Control of human walking is not thoroughly understood, which has implications in developing suitable strategies for the retraining of a functional gait following neurological injuries such as spinal cord injury (SCI). Bipedal robots allow simple elements of the complex nervous system to be analysed to quantify their contribution to motor control. RunBot is a bipedal robot which has been developed to operate through reflexes without using central pattern generators or trajectory planning algorithms. Switches in the feet identify ground contact and are used to activate motors in the legs, generating a gait cycle visually similar to that of humans. If a causal relationship can be established between foot contact information and muscle activity in humans during walking, rather than developing a complicated biologically realistic neural system to control stepping, the model used in the control of the RunBot robot could instead be simplified using this relationship and the associated filter functions transferring the sensory data into motor actions. By recording foot contact information and muscle activity (EMG) during human walking, both on a treadmill and overground, a relationship between heel contact and peaks in the muscle activity related to hip and knee joint actions was identified. Adaptive filtering was then used as a computational device to model the relationship between the recorded foot contact information and muscle activity data. Using these transfer functions, a minimal, linear, analogue control system for controlling walking could be created, based on the controller used in the RunBot robot. The human walking transfer functions were then applied to RunBot to analyse the produced gait. It was found that the gait cycle was stable and controlled, which is a positive indication that the control system has potential for use in controlling assistive devices for the retraining of an efficient and effective gait, with potential applications in SCI rehabilitation.
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Oludare, Simisola O. "The influence of rocker profile footwear on rollover during walking." Thesis, Georgia Institute of Technology, 2014. http://hdl.handle.net/1853/53735.
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Rocker profiles are one of the most commonly prescribed footwear modifications provided to individuals with impaired rollover. Impaired rollover is caused due to loss of neuromuscular function (i.e. stoke) or orthotic ankle constraint. When rollover is impaired, continued forward progression is interrupted and walking gait becomes less efficient (i.e. increased energy expenditure). Rocker profile footwear modifications are designed to mimic the functions of the anatomical ankle-foot rockers and provide its users with a smooth and efficient rollover. However, while there is theory governing the design of a rocker profile and subjective descriptions of rocker profile function, the extent to which a rocker profile footwear provides rollover has not yet been quantified. The aim of this study was to quantify effective and ineffective rollover and test whether our rocker profile provides effective rollover. We hypothesized that healthy subjects (n=4) walking with orthotic ankle constraint and the rocker profile (STOP) would have no change in rollover and energy expenditure outputs compared to walking with orthotic ankle free and rocker profile (FREE); but that healthy subjects (n=4) walking in STOP would have a change in rollover and energy expenditure outputs compared to walking with orthotic ankle constraint and no rocker profile (STOP-NR). To test this hypothesis, rollover was quantified as stance phase duration, cadence and radius of curvature and energy expenditure was quantified as heart rate and rating of perceived exertion. In addition to these outputs, we analyzed the ground reaction forces and duration of stance in early, middle and late stance period to determine the effects of the rocker profile footwear components. Through the rollover and energy expenditure outputs of the STOP, FREE and STOP-NR conditions, we quantified effective rollover as 0.29 (0.01) radius of curvature with a heart rate of 110.5(6.7) bpm and ineffective rollover as 0.69(0.12) radius of curvature with a heart rate of 131.5 (8.1) bpm. By creating this scale, we were able to determine that our rocker profile provided effective rollover (0.34[0.04] radius of curvature with a heart rate of 111.3[8.3] bpm). However, a future study with a greater sample size is needed to confirm these results.
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Yarbrough, Nancy Victoria 1945. "CONTROL OF TOUCHDOWN IN HUMAN LOCOMOTION (ELECTROMYOGRAPHY, WALKING, KINEMATICS)." Thesis, The University of Arizona, 1986. http://hdl.handle.net/10150/291309.
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Duffy, Catherine M. "The energy cost of walking in spina bifida : when does it become unacceptable?" Thesis, Queen's University Belfast, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.263320.
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Gutierrez, Elena M. "Gait strategy in myelomeningocele : movements, mechanics, and methods /." Stockholm, 2003. http://diss.kib.ki.se/2003/91-7349-644-8/.
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Shaikh, Inam Ul hasan. "Convergence analysis of ILC algorithms with application to compass gait bipedal walking robot." Thesis, University of Manchester, 2014. https://www.research.manchester.ac.uk/portal/en/theses/convergence-analysis-of-ilc-algorithms-with-application-to-compass-gait-bipedal-walking-robot(5a5068b1-85aa-4e7d-a1b8-c01124820c2a).html.
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At an early age, i.e., up to about 1-2 years, humans learn to walk and subsequently develop a robust and flexible gait. This is learned by repetitively taking similar steps and the experience is stored in the muscle/reflexive memory. Over the last 30 years, a variety of humanoid bipedal robots have been developed to copy the human gait. However, walking/locomotion is still a relatively difficult control problem due to its complex hybrid nature because of non-smooth dynamics. Although, simple walking comprises of single support in which one leg swings forward, then it impacts with ground for a brief double support phase and further transition of the other support leg to start a new swing. The steps are repeated again and again in a similar manner for walking over an even surface. As the swinging leg strikes the ground, it is a non-linear impact which poses a challenge since it causes non-zero initial state errors for each step which depend on the error in the gait at last moment for previous step. The usual bipedal control relies on complex techniques based on inverse kinematics, ZMP (Zero-Moment Pole) and COP (Centre Of Pressure) to generate the required control inputs for the joints. However, a basic cognitive assumption is that walking is a relatively simple task which can be learned and the biological systems have achieved it by simple repetitions. This has been over-looked in these control techniques. In the past, ILC has been proposed to solve the repetitive learning problems. The Iterative Learning Controller learns to generate the desired set of input signals to compensate for the output tracking errors in a sequential manner such that in the initial iterations, the signals values at earlier time indices have faster rate than the later ones. So, at the last time index the convergence is achieved after all the earlier ones. ILC learns/adapts the joint control for repetitive gaits. In this thesis it has been proposed to be used as a muscle memory where control signals are learnt for a repetitive batch. Thus, ILC equates to “learning a sequence of action by muscles”. Due to the transfer of state error in a cyclic manner from the end of a previous step/repetition to the recent step/repetition, the convergence has to be established in joint control and state space. Similar is the case of continuous walking where the ground impacts transfer part of the error in the gait to the start of a new step representing an impacting Cyclic ILC scenario. Hence, the ILC problem is changed from finite to an infinite horizon. The second problem occurs with the non-constant length of the iteration due to change in step size. The two scenarios have been considered: Firstly, when the control input is updated using ILC with identical initial conditions at the start of each repetition. Secondly, control input update under varying initial conditions leading to Cyclic ILC. The batch to batch evolution of control inputs at each sample time within a batch is formulated. The sequential convergence of control input generated by ILC algorithms has been investigated. The exact relationship for the rate of convergence of the control input has been formulated down to the sample-time level. This provides deeper insight about the ILC algorithms and hence exact factors affecting the convergence could be established. Limits of the learning process have been clearly demonstrated as well. Although, simpler D-ILC converges for zero initial error but for cyclic non-zero initial errors, it has offset error which corresponds to the initial state error. With proportional part, the PD-ILC algorithm has eliminated the offset error which has been illustrated for a damped pendulum and further implemented to bipedal locomotion. For reasons of energy efficiency, passive dynamics has been chosen for the compass gait model of the biped. The walking problem for the compass gait robot has been solved using the modified PD-ILC which utilizes the acceleration error term as well. The steady gait has been achieved for the compass gait robot on flat surface which has been verified by the phase portraits.
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Long, Leroy L. III. "An Experiment in Human Locomotion: Energetic Cost and Energy-Optimal Gait Choice." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1313584497.
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Giakas, Giannis K. "Time and frequency domain applications in biomechanics." Thesis, Manchester Metropolitan University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.389498.
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Dalton, Christopher. "Nordic Walking Improves Postural Alignment and Leads to a More Normal Gait Pattern Following 8 Weeks of Training in Older Adults." Thesis, Université d'Ottawa / University of Ottawa, 2016. http://hdl.handle.net/10393/34091.
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Background: Declines in gait velocity, stride length, cadence, and postural stability are common with advancing age and have further been linked to heightened fall risk and functional decline. Physical activity can slow or prevent such gait declines in older adults. In young adults, Nordic walking (NW) training has been shown to increase stride length and gait speed, yet has demonstrated inconsistent findings regarding joint loading, with reports of both increases and decreases in this respect. Further, research of this facet has very minimally been examined as it pertains to older adults.
Purpose: The aim of the present study was to determine both the initial effect, and the prolonged effect following an 8-week intervention, of Nordic walking (NW) on older adult gait performance and postural alignment and stability.
Methods: Gait and postural alignment and stability during NW and conventional walking were assessed and compared following an 8-week NW program (2x/week) in 12 healthy older adults (age: 68 ± 6.8 years; 8 female, 4 male). Participants performed six 5m walking trials, 3 with poles and 3 without, followed by two 6 Minute Walk Test (6MWT) trials, one with poles (WP) and the other without (NP). Gait characteristics and trunk measures in the sagittal and frontal planes were quantified using a 6 inertial sensor accelerometry system (APDM, Oregon, USA) as well as an eight camera 3-dimensional motion capture system (Vicon, Oxford, UK) with 2 force platforms (Kistler, Winterthur, Switzerland) embedded within. All variables were assessed using two-way repeated measures ANOVAs to compare NW to conventional walking and before and after the intervention.
Results: When comparing walking WP to NP at initial pre-testing, significantly longer stride length, slower gait speed, and increased double support time were found to coincide with decreases in power generation and absorption at the hip and knee WP. However, following prolonged practice, a longer stride length, faster gait speed, and increased power generation at pre-swing at the hip and power absorption during loading and terminal swing about the knee were found WP post-intervention.
Conclusions: An initial 8-week training period is necessary for novice NW in order to develop technique and to restore gait and postural alignment to more “normal” standards following training. Additionally, since the acquisition of the skill requires proper allocation of attention between two tasks: walking and pole manipulation, NW should be done so in a relatively safe environment, free of distraction and obstacles. Finally, with frail elderly, a longer acquisition period may be necessary since facilitation of movement must first occur.
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Peasgood, Michael. "Determinants of Increased Energy Cost in Prosthetic Gait." Thesis, University of Waterloo, 2004. http://hdl.handle.net/10012/880.
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The physiological energy requirements of prosthetic gait in lower-limb amputees have been observed to be significantly greater than those for able-bodied subjects. However, existing models of energy flow in walking have not been very successful in explaining the reasons for this additional energy cost. Existing mechanical models fail to capture all of the components of energy cost involved in human walking. In this thesis, a new model is developed that estimates the physiological cost of walking for an able-bodied individual; the same cost of walking is then computed using a variation of the model that represents a bi-lateral below-knee amputee. The results indicate a higher physiological cost for the amputee model, suggesting that the model more accurately represents the relative metabolic costs of able-bodied and amputee walking gait. The model is based on a two-dimensional multi-body mechanical model that computes the joint torques required for a specified pattern of joint kinematics. In contrast to other models, the mechanical model includes a balance controller component that dynamically maintains the stability of the model during the walking simulation. This allows for analysis of many consecutive steps, and includes in the metabolic cost estimation the energy required to maintain balance. A muscle stress based calculation is used to determine the optimal muscle force distribution required to achieve the joint torques computed by the mechanical model. This calculation is also used as a measure of the metabolic energy cost of the walking simulation. Finally, an optimization algorithm is applied to the joint kinematic patterns to find the optimal walking motion for the model. This approach allows the simulation to find the most energy efficient gait for the model, mimicking the natural human tendency to walk with the most efficient stride length and speed.
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Kavanagh, Justin, and n/a. "Dynamic Stability of the Upper Body During Walking." Griffith University. School of Physiotherapy and Exercise Science, 2006. http://www4.gu.edu.au:8080/adt-root/public/adt-QGU20070219.172055.
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The general purpose of this study was to examine factors that may influence acceleration characteristics of the upper body during walking, thereby clarifying the means by which the postural system facilitates dynamic stability of the upper body during walking. Upper body accelerations were measured during a range of straight-line walking tasks. Time domain, frequency domain, signal regularity and coupling analyses were used to 1) provide new insight into gait-related upper body accelerations during walking in normal healthy adults, and 2) determine how the postural system accommodates to perturbations that challenge upper body stability during walking. The specific perturbations to the postural system that were examined in the present study were the normal ageing process, changes in walking speed, and fatigue of the cervical and lumbar erector spinae. In general, the patterns of accelerations measured at the level of the head were an attenuated version of those at the lower trunk during normal walking. Power spectral analysis revealed that both the head and lower trunk in the anterior-posterior (AP) and vertical directions (VT) directions were characterised by a single peak frequency corresponding the step frequency during normal walking. However, the most notable of all attenuation profiles was the difference between accelerations of the head and lower trunk in the mediolateral (ML) direction. ML trunk accelerations were characterised by multiple low amplitude frequency peaks, which were attenuated to a single peak at the head corresponding to stride frequency. The coupling between acceleration directions was greater for the head than the lower trunk, suggesting that the postural system promotes a coordination strategy which enhances global stability of the head. Subdividing the upper body into neck and trunk segments facilitated a more comprehensive description how the gait-related oscillations are prevented from impacting on the motion of the head. Overall, acceleration amplitude, power content, and regularity were predominantly regulated by the trunk segment, especially for the AP and ML directions. This suggests that the trunk segment plays a critical role in modulating the amplitude and structure of gait-related oscillations prior to reaching the neck segment and thus the head. It was envisaged that examining factors that may challenge the individual (the normal ageing process), and the walking task (changes in walking speed, and induced fatigue of the upper body), would provide new insight into the extent to which the postural system prioritises head stability during walking. Regardless of the challenges imposed on the postural system due to the ageing process, upper body movement was organised in a manner which assisted in maintaining a degree of head stability comparable to those observed under normal walking conditions. Similarly, the importance that the postural system places on maintaining head stability was evident in the attenuation characteristics of the trunk and neck segments when walking speed was manipulated, and neuromuscular fatigue induced. Manipulating walking speed highlighted the critical role that the trunk segment has in regulating upper body accelerations arising from gait-related events. Aside from a minor contribution from the neck segment in the direction of travel at preferred and fast walking speeds, regulation of accelerations occurred due to the dynamics of the trunk segment. Inducing neuromuscular fatigue of the cervical and lumbar erector spinae groups (CES and LES) revealed compensatory movement strategies of the upper body, with a view of enhancing head stability. For several variables quantifying attenuation, fatiguing one muscle group, such as the CES, resulted in changes in the dynamics of another level of the upper body, such as the trunk segment. The trunk segment was particularly dominant in regulating upper body accelerations under fatigued conditions, further reinforcing the importance to control accelerations prior to reaching the neck and head. Overall, the results of this study suggest that optimal head stability is reliant on the trunk segment providing a stable base of support for the neck and head. By regulating accelerations via the trunk segment, the postural system is effectively regulating the orientation of the neck and head, and the inclusive sensory organs. It was evident that the postural system prioritises, and in general, maintains head stability during walking despite challenges imposed on upper body stability.
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Hatzitheodorou, Philip Andrew. "An Experimental Study on Passive Dynamic Walking." Scholar Commons, 2015. https://scholarcommons.usf.edu/etd/5498.
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In this study, a previously designed passive dynamic walker (PDW) is built out of aluminum and plastic. The aim of the study was to produce an asymmetrical PDW and to compare the results to a computer simulation to validate the mathematical model. It also aimed at identifying the limitations of using additive manufacturing to create components for a PDW as well as gain insights on asymmetric systems.
Beginning with a five mass kneed model, parameters were varied to produce up to a nine mass kneed model solution. The nine mass model allows more variability in added mass locations and separates the zeroth, first, and second moments of inertia. To validate asymmetric gait, step length and step time of the prototype were compared to the simulation. The walker, unable to produce a steady gait, failed to match the asymmetric simulation. More than four times the amount of symmetric data was found compared to asymmetric data. Successful runs of symmetric gaits were approximately double than for asymmetric gaits. The reason for unequal successes is thought to be due to greater instability of asymmetric systems. This instability is thought to be due to inertia from a constant state of hanging motion. 3D printing proved useful in simplifying components and reducing waste but the polymers used did not have enough strength when mass was added to the system. Joining differing materials on the legs was difficult to keep in place. A smaller more robust design could solve these problems.
This study focused on understanding physically asymmetric PDWs. These simple robots separate the neurological and mechanical controls of walking and are advantageous for studying physical parameters of human gait. Once a reliable asymmetric walker is built, further research could alter the foot shape or knee location to reverse the process, thus having a PDW walk symmetric. Once a walker is successfully reverted from walking asymmetrical to symmetrical, these parameters could be then applied to human subjects. An example of this would be for prosthetic foot design.
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Ness, Lanitia. "Effects of Vibration on Spinal Circuitry Related to Spasticity and Walking." Scholarly Repository, 2008. http://scholarlyrepository.miami.edu/oa_dissertations/329.
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In individuals with spinal cord injury (SCI) who have disrupted communication between the brain and spinal cord, vibration may mimic functions formerly served by the lost or impaired supraspinal inputs resulting in more normal reflex modulation and improved walking function. Three experiments assessed the effects of vibration on spinal locomotor-generating circuitry, spinal reflex activity, and walking function. In Experiment 1, localized leg vibration was used to elicit air-stepping responses in the lower extremities. We compared responses of individuals with SCI to those of non-disabled (ND) individuals and assessed the influence of severity injury and locomotor training on the air-stepping response in individuals with SCI. Our results indicate that vibration of the tensor fascia latae elicited more consistent and robust responses than vibration of the quadriceps or hamstrings muscles. Individuals with SCI had less consistent and robust responses than ND individuals. In those with SCI, neither severity of injury nor locomotor training influenced the robustness or consistency of the response. In Experiment 2, we investigated the effect of whole-body vibration (WBV) on spasticity, as measured by spinal stretch reflex (SSR) excitability, in individuals with SCI. We also assessed differences in the influence of WBV among individuals who used antispastic medications and those who did not. Subjects were tested before and after participation in a 3 day/week, 12-session WBV intervention. There was a significant reduction in spasticity that persisted for several days following the WBV intervention. The amount by which spasticity was reduced was not different in those who used antispastic agents compared to those who did not use these agents. In Experiment 3, we assessed the effects of the 12-session WBV intervention on walking function. WBV was associated with significant increases in walking speed, cadence, step length of the stronger leg, and consistency of hip-knee intralimb coordination. Increases in cadence and stronger-leg step length correlated with improvements in walking speed. These results suggest that WBV may represent an approach to decreasing spasticity, and may be useful for individuals in whom spasticity interferes with function. Furthermore, vibration appears to have a beneficial effect on walking function, perhaps by influencing spinal locomotor-generating circuitry.
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Birtles, Deirdre Beth. "Postural stability during standing and walking and the effects of age." Thesis, University College London (University of London), 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.313799.
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