Feasibility Analysis of a Powered Lower-Limb Orthotic for the Mobility Impaired User

Powered orthotic devices can be used to restore mobility to the impaired user, and may thereby assist them in daily living tasks. An investigation is performed herein to examine the feasibility of a powered lower-limb orthotic in assisting the sit-to-stand task by 50% of the required torque. Feasibility is considered via simulation. A three-link sit-to-stand model, which is driven by kinematic data, is developed. Models of a Pneumatic Muscle Actuator and a DC motor are used to determine which of the two technologies can make a more appropriate contribution to the sit-to-stand task. Simulation revealed that both the Pneumatic Muscle Actuator and the DC motor are reasonable actuator choices, and neither limited the ability to achieve 50% torque assistance. The ability to assist the task was, however, limited by the ability to derive a control signal for the actuator from the user-orthotic interface. It was concluded that the user-orthotic interface requires further investigation. It was also found that while both actuator technologies are suitable for contributing 50% of the required torque, the Pneumatic Muscle Actuator is preferable due to its ability to scale to greater torques

A biomechanical investigation of seated balance and upright mobility with a robotic exoskeleton in individuals with a spinal cord injury

Spinal cord injury (SCI) is a complex medical condition with multiple sequelae. The level and severity of a lesion will determine the degree of disability and associated co- morbidities, the most obvious of which is paralysis. Other concomitant issues, such as muscle contractures, poor seated posture and fear of falling, can also lead to a reduced quality of life. Although there is currently no cure for SCI, many of the comorbidities can be managed or mitigated through technology and physical rehabilitation practices.The aim of this thesis was to inform spinal cord injury (SCI) mobility rehabilitation, focusing on postural control and upright stepping using robotic assisted gait training (RAGT). A systematic review investigating RAGT use in SCI concluded that although RAGT has the potential to benefit upright locomotion of SCI individuals, it should not replace other therapies but should be incorporated into a multi-modality rehabilitation approach.Seated postural control, upper-body posture and fear-of-falling in SCI individuals were also explored. Stability performance and control demand were compared between high- and low-level injury groups as was fear-of-falling. An individualised limit of stability boundary (LOS) facilitated the differentiation between high- and low-level injuries during static tasks; however, its use during dynamic tasks was limited and potentially influenced by fear-of-falling.Few studies have quantified the user’s motion inside a lower limb robotic exoskeleton (LEXO), and none have reported marker placement repeatability. Standard error of measurement was reported for three-dimensional trunk and pelvic orientations and hip, knee and ankle angles in the sagittal plane during level walking. This revealed the marker set and placement to produce good levels of agreement between visits, with most values falling between the accepted standard of 2-5o. These findings indicated that the marker placement was repeatable and could be used in the subsequent chapters involving motion capture of overground walking.Three-dimensional gait parameters of able-bodied individuals walking with and without a LEXO at two speeds (comfortable (CMBL) and speed-matched (SLOW) to the LEXO) were investigated. Statistical parametric mapping revealed significantly different waveforms at the ANOVA level for all kinematic variables, however minimal differences in sagittal plane lower limb kinematics were identified between LEXO and SLOW gait, suggesting LEXO gait resembled slow walking when speed-matched. Altered kinematics of the pelvis and trunk during LEXO use suggest that overground exoskeletons may provide a training environment benefiting postural control training.Finally, the biomechanical characteristics of able-bodied and SCI users walking in an overground LEXO were investigated. Variables associated with neuroplasticity in SCI (hip extension and lower limb un-loading) were not significantly different between groups, indicating that afferent stimuli to facilitate neuroplastic adaptations in individuals with a SCI can be generated during LEXO gait. Upper-body orientation facilitated stepping and maintained balance, thereby requiring the participant’s active involvement.This thesis has provided evidence that LEXOs can deliver appropriate stimuli for upright stepping and that upper-body engagement can facilitate postural control training, potentially leading to improved seated postural control

Applications of EMG in Clinical and Sports Medicine

This second of two volumes on EMG (Electromyography) covers a wide range of clinical applications, as a complement to the methods discussed in volume 1. Topics range from gait and vibration analysis, through posture and falls prevention, to biofeedback in the treatment of neurologic swallowing impairment. The volume includes sections on back care, sports and performance medicine, gynecology/urology and orofacial function. Authors describe the procedures for their experimental studies with detailed and clear illustrations and references to the literature. The limitations of SEMG measures and methods for careful analysis are discussed. This broad compilation of articles discussing the use of EMG in both clinical and research applications demonstrates the utility of the method as a tool in a wide variety of disciplines and clinical fields

Physical Diagnosis and Rehabilitation Technologies

The book focuses on the diagnosis, evaluation, and assistance of gait disorders; all the papers have been contributed by research groups related to assistive robotics, instrumentations, and augmentative devices

Using Model-based Optimal Control for Conceptional Motion Generation for the Humannoid Robot HRP-2 14 and Design Investigations for Exo-Skeletons

The research field of bipedal locomotion has been active since a few decades now. At one hand, the legged locomotion principle comprises highly flexible and robust mobility for technical applications. At the other hand, a thorough technical understanding of bipedalism supports efforts of clinicians and engineers to help people, suffering from reduced locomotion capabilities caused by fatal incidents. Since the technology enabled the construction of numerous robotic devices, among them: various humanoids, researchers started to investigate bipedalism by abstraction and adoption for technical applications. Findings from humanoid robotics are further exploited for the construction of devices for human performance augmentation and mobility support or gait rehabilitation, among them: orthosis and exo-skeletons. Although this research continuously progresses, the motion capacities of humanoid robots still lack far behind those of humans in terms of forward velocity, robustness and appearance of the overall motion. Generally, it is claimed that the difference of performance between humans and robotics is not only due to the limiting characteristics of the employed technology, e.g. constructive lack of specific determinants of gait for bipedalism or dynamic limits of the actuation system, but as well to the adopted methods for motion generation and control. For humanoid robotics, methods for motion generation are classified into optimization-based methods and those that employ heuristics, that are mostly distinguished based on the problem complexity (computation time) and the resulting dynamic error between the generated motion and the dynamics of the real robot. The implementation of the dynamic motion on the robotic platform is usually comprised with an on-line stabilizing control system. This control system must then identify and resolve instantaneously the dynamic error to maintain a continuously stable operation of the device. A large dynamic error and breach of the dynamic limits of the actuation system can quickly lead to a fatal destabilization of the device. This work proposes a contribution to the model computation and the strategy of the problem formulation of direct multiple-shooting based optimal control (Bock et. al.) for dynamically stable optimization-based motion generation. The computation of the whole-body dynamic model inside the optimization relies either on forward or inverse dynamics approach. As the inverse dynamics approach has frequently been perceived as less resource intensive than the forward dynamics approach, a new generic algorithm for insufficiently constrained, under-actuated dynamic systems has been developed and thoroughly tested to comply with all numerical restrictions of the enveloping optimization algorithm. Based on this contribution, various optimal control problems for the humanoid platform HRP-2 14 have been formulated to assess the influence of different biologically inspired optimization criteria on the final motion characteristics of walking motions. From thorough bibliographic researches a dynamically more accurate model was comprised, by taking into account the impact absorbing element in the ankle joint complex. Based on the experiences of the previous study, a problem formulation for the limiting case of, dynamically overstepping an obstacle of 20cm x 11cm (height x width) with only two steps, while maintaining its stable operation was accomplished. This is a new record for this platform. In a further part, this work proposes an iterative comprehensive model-based optimal control approach for the conception of a lower limb exo-skeleton that respects the integrated nature of such a mechatronic device. In this contribution, a human effectively wearing such a lower limb exo-skeleton is modeled. The approach then substantiates all system components in an iterative procedure, based on the complete system model, effectively resolving all complex inter-dependencies between the different components of the system. The study in this work is conducted on an important benchmark motion, walking, of a healthy human being. From this study the limiting characteristics of the system are determined and substantial propositions to the realization of various system components are formulated

The development of ergonomics design criteria for powered human movement systems

This research developed from a concept for a powered exoskeletal system for manipulating a person's posture to provide them with physical sensations as though taking part in an activity in which they otherwise would not be able to participate. The aim for this research was to develop a set of criteria relating to this physical manipulation, which could be used, in conjunction with visual and audio stimuli, to govern the design of a commercial personal entertainment simulator for use by members of the public. Investigations revealed that there is currently no existing system comparable to this proposed simulator. Therefore, various fields were researched, including robotics, physiotherapy, virtual reality, haptics and existing simulators; with a view to combining elements of these fields for the development of a manipulation system appropriate to public entertainment use. A survey was conducted on members of the public to investigate their experiences of sports, theme park rides and virtual reality; their personalities; and their opinions of the proposed simulator. This survey indicated that the likely users of such a system would be sensation-seeking, physically active people. The activities which generated the most interest were those which were hazardous, difficult, or required long distance travel. To be consistent with these findings, practical trials were undertaken using the sport of skiing as the context for conducting practical investigations into postural manipulation. Existing and original studies of the movements involved in skiing revealed the complexity of this activity, and the variety of techniques employed by different skiers. These findings, combined with the survey data and earlier investigations, led to the development of a versatile prototype system which could accommodate this variability and impose customised skiing movements on volunteers. Volunteer trials using this prototype demonstrated that members of the public were willing to have their postures controlled by external forces, and although some participants were apprehensive at first, they all reported the experience to be enjoyable. Tests with different applied movements showed that users were comfortable with manipulations at speeds and accelerations up to and exceeding those employed in skiing for real. The principal criteria concluded from these trials were that it is possible to safely and comfortably manipulate human postures through external technology, and that this external control can be used to provide an enjoyable and exhilarating entertainment experience.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

INERTIAL MOTION CAPTURE SYSTEM FOR BIOMECHANICAL ANALYSIS IN PRESSURE SUITS

A non-invasive system has been developed at the University of Maryland Space System Laboratory with the goal of providing a new capability for quantifying the motion of the human inside a space suit. Based on an array of six microprocessors and eighteen microelectromechanical (MEMS) inertial measurement units (IMUs), the Body Pose Measurement System (BPMS) allows the monitoring of the kinematics of the suit occupant in an unobtrusive, self-contained, lightweight and compact fashion, without requiring any external equipment such as those necessary with modern optical motion capture systems. BPMS measures and stores the accelerations, angular rates and magnetic fields acting upon each IMU, which are mounted on the head, torso, and each segment of each limb. In order to convert the raw data into a more useful form, such as a set of body segment angles quantifying pose and motion, a series of geometrical models and a non-linear complimentary filter were implemented. The first portion of this works focuses on assessing system performance, which was measured by comparing the BPMS filtered data against rigid body angles measured through an external VICON optical motion capture system. This type of system is the industry standard, and is used here for independent measurement of body pose angles. By comparing the two sets of data, performance metrics such as BPMS system operational conditions, accuracy, and drift were evaluated and correlated against VICON data. After the system and models were verified and their capabilities and limitations assessed, a series of pressure suit evaluations were conducted. Three different pressure suits were used to identify the relationship between usable range of motion and internal suit pressure. In addition to addressing range of motion, a series of exploration tasks were also performed, recorded, and analysed in order to identify different motion patterns and trajectories as suit pressure is increased and overall suit mobility is reduced. The focus of these evaluations was to quantify the reduction in mobility when operating in any of the evaluated pressure suits. This data should be of value in defining new low cost alternatives for pressure suit performance verification and evaluation. This work demonstrates that the BPMS technology is a viable alternative or companion to optical motion capture; while BPMS is the first motion capture system that has been designed specifically to measure the kinematics of a human in a pressure suit, its capabilities are not constrained to just being a measurement tool. The last section of the manuscript is devoted to future possible uses for the system, with a specific focus on pressure suit applications such in the use of BPMS as a master control interface for robot teleoperation, as well as an input interface for future robotically augmented pressure suits

Aerospace Medicine and Biology: A cumulative index to a continuing bibliography

This publication is a cumulative index to the abstracts contained in Supplements 138 through 149 of AEROSPACE MEDICINE AND BIOLOGY: A CONTINUING BIBLIOGRAPHY. It includes three indexes -- subject, personal author, and corporate source

Proceedings of the 5th international conference on disability, virtual reality and associated technologies (ICDVRAT 2004)

The proceedings of the conferenc

Proceedings of the 7th international conference on disability, virtual reality and associated technologies, with ArtAbilitation (ICDVRAT 2008)

The proceedings of the conferenc