Dissertations / Theses on the topic 'Wheelchair and seating systems'

High-tone extensor thrust is common to those with cerebral palsy and those suffering spinal cord injuries. It is a muscle-control phenomenon that causes the body to straighten spastically. One goal of this thesis is to design a dynamic seating system that moves with respect to the wheelchair frame, allowing the seat to move with the user during an extensor thrust and reduce forces. One unique challenge is that the seat needs to remain rigid during normal functional activities and only become dynamic when an involuntary thrust is detected. A second goal of this thesis is to design a control scheme that is able to differentiate between these two types of motion. These design goals are initially investigated with a hinged-seatback system, instrumented with sensors to allow for the detection of thrusts and to actively control seating components. A full seating system is then built to allow for full-body extensor thrusts, involving the seatback, seat bottom, and leg rest of the wheelchair. This system is analyzed for effectiveness of reducing forces on the body during an extensor thrust. Another serious problem for this segment of the population is pressure ulcers. These are caused by prolonged pressure on the skin from weight-bearing bony prominences. Various seating system configurations are known to help with pressure relief. The three standard configurations for a chair are tilt, recline, and standing. The final goal of this thesis is to measure and compare the effectiveness of these three methods for their ability to relieve pressure on the seat bottom. To accomplish this, a powered wheelchair with built-in capabilities for recline and standing is mounted to a tilting mechanism. Test subjects are used to experimentally compare the effectiveness of each method for pressure reduction using pressure mats on all weight-bearing surfaces. A 2D model is also developed and validated with the experimental results.

Esta dissertação consiste em um estudo teórico exploratório sobre o projeto sistemático de sistemas de assento especiais para cadeiras de rodas, com ênfase em seus aspectos conceituais e funcionais. De acordo com os princípios da tecnologia assistiva - que consiste no uso de tecnologias para o atendimento das necessidades de pessoas com deficiência - o objetivo das ajudas técnicas deve ser a promoção da atividade e participação social através da compensação de deficiências, promovendo a funcionalidade. Assim, foi feita uma revisão da literatura a respeito da adequação postural do usuário de cadeira de rodas, e dos fatores que contribuem para sua saúde, sua funcionalidade e seu conforto ou desconforto na posição sentada, permitindo a identificação de suas necessidades explícitas e implícitas. Com o uso da Metodologia de Projeto Sistemático de Pahl e Beitz, da Metodologia de Projeto Axiomático e da Teoria da Solução dos Problemas Inventivos (TRIZ), foi elaborada uma lista de requisitos funcionais através do mapeamento entre o domínio das necessidades do usuário e o domínio funcional do sistema de assento. Em seguida, elaborou-se uma estrutura funcional, demonstrando os principais elementos e conexões funcionais do sistema, sendo por fim comentados e propostos alguns princípios de solução para cada uma das sub-funções principais encontradas, envolvendo a análise de princípios de solução de sistemas existentes e de sistemas análogos em outras áreas tecnológicas. Concluiu-se que a imobilidade é o fator primário que desencadeia os diversos problemas de saúde e funcionalidade do usuário associados ao uso destes sistemas de assento, e que portanto a função principal desses sistemas deve ser a de permitir, facilitar e promover positivamente a alternância freqüente de posição. Além disso, verificou-se o papel fundamental dos fluxos de informação responsáveis pela determinação do propósito homeostático da movimentação, que objetiva a redistribuição contínua das tensões locais nos tecidos, além do favorecimento da ação motora voluntária pela estabilização e mobilização seletiva de movimentos corporais.
This work is an exploratory theoretical study on systematic design of special wheelchair seating systems, emphasizing its conceptual and functional aspects. According to the principles of assistive technology - which consists in the use of technologies applied to the caring of the needs of people with disabilities - the objectives of technical aids should be the promotion of optimal individual functionality. Thus, a literature review has been made on the theme of postural seating clinic, and the factors related to the health, the functionality, and the comfort or discomfort in the sitting position, allowing the identification of many explicit and implicit needs. By using the Systematic Design approach of Pahl & Beitz, complemented by some principles of Axiomatic Design and TRIZ, a functional requirements list has been made, consisting in the mapping between the customer needs in the customer domain and the functional requirements in the functional domain. In the next step, a functional structure has been created, showing the main functional elements and connections of the seating system, followed by the proposal of some working principles regarding the main identified sub-functions, including the analysis of analog technical systems of other technological fields. It was concluded that immobility is the main causative factor leading to the many functional and health problem associated with the sitting position, and therefore the main function of special seating systems must be to allow and actively promote frequent position changes. Moreover, it has become evident that information flows have a capital importance in proper functioning of seating systems, since they convey the homeostatic purpose of the movements being made, in order to continually redistribute and alleviate the local soft tissue deformations, and to promote the selective stabilization and motion of body segments that permit functional motor action.

A study has been conducted into the development of Impact Management Seating Systems (IMSS's) for improved occupant protection during rear impacts. The seating systems incorporate methodologies that enable the supporting surfaces to pivot in a controlled manner during the onset of the impact event. This enables the seated occupant to penetrate an outer perimeter frame, whilst simultaneously having the effective ride height lowered. This response is typically referred to as the 'Catchers- Mitt' principal, and provides the occupant with localised 'ride-down', and optimum positioning with respects to the head restraint. Such seating systems can compliment the 'ride-down' characteristics provided by vehicle' crush-zones', or in the case of small and Low Mass Vehicle (LMV) designs, which can suffer from inefficient 'crush-zones' due to geometric restrictions, can be the primary source of impact management. Pivotal systems typically rely on the use of yielding elements to initiate the desired deployment. However, these are inherently restrictive in their ability to adapt to changes in occupant mass and impact magnitude. Solutions are presented to address this and other limitations. Such solutions include the use automatic inflation/deflation technologies, and Siding Plate Anchorage Systems that provide the seated occupant with a supportive surface during deployment of the pivotal mechanisms, and the reposition of the restraint system to address issues with 'rebound-reactions' and/or multiple impact events. LS-DYNA simulations determined the effectiveness of the developed seating systems in controlling a dummy response. Significant reductions in head acceleration and the movements thought responsible for whiplash and Whiplash Associated Disorders were achieved. The realisation of the seating systems is examined. Consideration is given to issues associated with seat mass, to enable the systems to be installed within Low Mass Vehicle (LMV) designs without compromising environmental gains.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1996.
Includes bibliographical references (leaves 73-74).
A new type of seat cushion has been developed. The present use of the cushion is in wheelchair seating, but it may ultimately have application to general seating, particularly in situations where comfort is a significant consideration. The cushion is intended to optimally distribute the interface pressure on the seat of a wheelchair user, as well as to provide an opportunity for active pressure management. The principal goal in developing this cushion is the prevention of pressure sores (decubitis ulcers). The theoretical and design considerations upon which the cushion was developed are presented. Experimental materials data, as well as results of a prototype system, are supplied. A prototype cushion has been produced, and additional work is ongoing. The cushion uses vacuum to manipulate the elastic/collapse properties of open-cell foam; effectively setting a maximum pressure at the human interface. Assuming appropriate auxiliary hardware, pumps, controllers, and sensors it would be appropriate to use this cushion as the basis of an actively controlled seating system.
by Michael T. Bush.
M.S.

Background. Adaptive seating systems are used with children with cerebral palsy to promote function and independence and to prevent the development of deformity. A seating system that uses a sacral pad and kneeblock to control the pelvis was investigated. Methods A mixed methodology design was employed. Acceptability was addressed through the development and administration of matching questionnaires to the parents and therapists of the children participating in the project. Effectiveness was investigated by measuring pressure at the sacral pad, force exerted through a kneeblock, seated postural alignment and seated function; during a case controlled trial, where children were seen 6 times over a period of 6 months. Children removed their kneeblocks for a period of one month between visits 3 and 4. The force, pressure and postural alignment data were statistically analysed. Theoretical biomechanical analyses were also performed. Results Questionnaire results showed important differences between parents and therapists views of the seating systems. Therapists concentrated on postural management, whilst parents were concerned with day-to-day management of the child. There were few statistically significant differences over the 6-visit trial for force, pressure or postural alignment. There were no statistically significant correlations between force measured at the kneeblocks and pressure exerted through a sacral pad, nor between force and postural alignment. Statistically significant effects on hip abduction and hip rotation were found on removal of kneeblocks. Finally, individual biornechanical analysis illustrated positive effects for hip abduction for some children, but a tendency to increase deformity in half of the children. Conclusions Adaptive seating systems that use a kneeblock and sacral pad may achieve hip rotation and abduction for children with cerebral palsy. However, no other improvements in posture were seen, and biomechanical analysis showed an increase in tendency of the children to develop secondary deformity.

In the design of autonomous mobile robots, databases have been used mainly to store information on the environment in which the device is to operate. For most of the models and ready systems, the database when used, is not a stand alone component in the system, rather it is only intended to keep static information on the disposition and properties of objects on the map.

Thesis (MScEng)--University of Stellenbosch, 2004.
ENGLISH ABSTRACT: The purpose of this study was to investigate the specification and use of appropriate seating systems to reduce whole-body vibration exposure in typical vehicles used in South African industry. As part of this study six suspension seats, which the manufacturers claim satisfy the requirements in ISO 7096 (2000), were tested. Six test subjects, three light and three heavy as specified in ISO 7096, were used to estimate the seat transmissibility functions in the vertical direction of the six different suspension seats. Transmissibility functions were measured in the laboratory using two excitation levels, 1m/s2 and 2 m/s2 r.m.s., of broadband frequency vibration and a spectrum approximating the EM5 spectral class in ISO 7096. SEA T values were calculated for operational vibration data measured in an articulated dump truck and a three-wheeled logger. It was shown that SEAT values for the EM1 spectral class could not be reliably estimated from seat transmissibility functions and need to be measured directly in the time-domain. The measurement procedures and seat selection criteria developed in this research project were used to compile a set of "Design Guidelines for Seat Selection for Whole-Body Vibration Control in Industrial Vehicles". These guidelines will provide manufacturers with an easy-to-implement methodology to control whole-body vibration transmitted to the operators of industrial vehicles and to comply with international regulations for whole-body vibration transmission.
AFRIKAANSE OPSOMMING: Die doel van die studie was om die spesifikasies en gebruike van geskikte sitplek stelsels van uit Suid Afrikaanse industriële voertuie, wat heel-liggaam vibrasies verminder, te ondersoek. Ses suspensiesitplekke, wat deur die vervaardigers voorgeskryf word, is getoets om te sien of hulle aan die ISO 7096 (2000) vereistes voldoen. Ses persone, waarvan drie lig en drie swaar is, soos in ISO 7096 voorgeskryf, is gebruik om die sitplek oordragsfunksies in die vertikale rigting vir die ses verskillende suspensiesitplekke te skat. Die oordragsfunksies is in die laboratorium gemeet deur twee opwekkingsvlakke, 1m/s2 en 2m/s2 w.g.k., van wyeband frekwensie vibrasie en n spektrum beraam tot die EMS spektrum soos in ISO 7096. 'SEA T' waardes was vanaf operationele vibrasie data wat in ge-artikuleerde vragmotors en driewiel- 'loggers' gemeet is bereken. Daar is gewys dat betroubare 'SEAT waardes vir die EM1 spektrum nie van sitplek oordragsfunksies geskat kan word nie, maar dat dit eerder direk van die tyd-gebied afgelees moet word. Die metings prosedures en die sitplek keuse vereistes wat in die navorsingsprojek ontwikkel is, is gebruik om "Ontwerp Riglyne vir Sitplek Keuse Vereistes vir Heel- Liggaam Vibrasie in Industriële Voertuie" saam te stel. Hierdie riglyne sal vervaardigers met maklik toepasbare metodes toerus om heel-liggaam vibrasie, wat oorgedra word na industriële voertuig operateurs, te beheer en om aan internasionale regulasies t.o.v. heel-liggaam vibrasie oordrag te kan voldoen.

Occupant Restraint Systems (ORS) have been widely used in Public Service Vehicles (PSVs). A Wheelchair Tiedown and Occupant Restraint System (WTORS) has been developed to provide effective occupant protection for disabled people who are seated in wheelchairs. An international laboratory study had been conducted to produce a compliance test protocol that included specification of the sled deceleration versus time history and the crash pulse corridor. Currently effort at the international level is being focused through the International Standards Organisation (ISO) to produce standards for WTORS and transportable wheelchairs. Dynamic sled testing of WTORS was conducted in Middlesex University Road Safety Engineering Laboratory (MURSEL) to develop a test protocol in a WTORS System. This research has been concerned with the effects to which the occupant of a wheelchair secured by a WTORS is subjected in a frontal impact. Both occupant Forward Facing Frontal (FFF) and Rearward Facing Frontal (RFF) impact configurations have been considered. A Surrogate wheelchair with a tiedown restraint System, a Surrogate occupant restraint System, and an Anthropomorphic Test Dummy (ATD) were used to facilitate highly controlled tests. Production wheelchairs were also crash tested to validate the response of the Surrogate System. A 48 km/h-20g crash pulse falling within the ISO standard crash pulse corridor was specified. The Crash Victim Simulation (CVS), one of the computer modelling methods, and Finite Element Analysis (FEA) models were designed to study the dynamic response of a restrained wheelchair and its occupant in a crash environment. Two CVS computer packages: MADYMO®, DYNAMAN® and one of FEA programs: PAFEC were used in WTORS models to predict the occupant response during impacts and hence provide data to optimise future system design. A modelling protocol for WTORS was developed based on the results of ninety (90) sled tests of WTORS Surrogate system and forty (40) dynamic tests of production wheelchairs. To illustrate the potential of these models the results of simulations were validated by sled tests. A random effects Statistical method was used to quantify the results. The load-time histories were also traced to qualify the test and model results. A literature review highlighted twenty years of wheelchair crash research. The correlation between computer model and experimental results was made more accurately. The modelling technique of interconnection of FEA models into CVS program was also introduced. The velocity profile and the natural frequency of WTORS analysis were used to explain why the wheelchair and dummy experienced acceleration amplifications relative to the sled. The shoulder belt load at floor-mounted configuration was found to be higher than that at B pillar configuration. Energy principles were also applied to show why more compliant wheelchair tiedown Systems subjected restraints to a less severe crash environment. A decomposition of forces using the computer model showed why quasi-static analysis is insufficient in WTORS design. It is concluded that the B pillar anchorage of the occupant diagonal strap is superior to the floor-mounted configuration.

The calibration of a 9 degree of freedom (DOF) robotic manipulator using multiple three axis accelerometers and an embedded system will be accomplished in this work. The 9-DOF robotic system used in this study is a 7-DOF robotic arm attached to a 2-DOF power wheelchair. Combined they create a Wheelchair Mounted Robotic Arm (WMRA). The problem that will be solved by this thesis is the calibration of the robotic system during start up. The 7 DOF robotic arm is comprised of rotational joints only. These joints have dual channel encoders to determine the joint position, among other useful data. The problem with dual channel encoders is that when power to the encoders is turned off and the motor is moved, then the robot controller does not have accurate position data when the system is powered again. The proposed calibration method will find the angles of two joints per three axis accelerometer. Four separate accelerometers are mounted on different locations of the 7 DOF robotic arm to determine the arms joint values. To determine the orientation of the base frame, an inertial measurements unit (IMU) is mounted to the origin of the base frame. By using this system of accelerometers and inertial measurement unit, the WMRA can be completely calibrated during system start up. The results collected for this calibration method show joint estimations with an error of +-0.1 radians for each joint. The results also show an accumulation of error for joints that are farther from the base frame.

Nowadays disabled persons are actively integrated into social life. Different compensatory equipment allows them to work and travel independently and one of such means is the wheelchair. Not every disabled person has possibilities to travel by his own car, it is more convenient to use public transport facilities. Transportation safety of the wheelchair users is one of the most important problems facing engineers and transit providers, becouse improperly or totally unsecured wheelchair can lose the stability and tip over during the emergency driving situations. The main object of the scientific research work is complex dynamic system "Man - Wheelchair - Vehicle", whis is under action of environmental factors (road roughness, motion oscillations of vehicle). The main tasks of the work are to form and research nonlinear model of dynamic system considered and to define system's stability limits, providing means for safe travel; to determine main characteristics of the external action and analyze its influence on to dynamic system; to build engineering computation methodology for estimation of the rational parameters to fasten the wheelchair to the vehicle.

博士
國立成功大學
生物醫學工程學系
103
Elderly adults with lower limb disorders sitting on a wheelchair for an extended period of time may experience numerous complications. Critical complications in clinical practice include back pain, pressure ulcers, and decreased pulmonary function. Wheelchair seating system is a key factor that influences spinal angle, back muscle activation, interface pressure, pulmonary function, and subjective discomfort. Although numerous studies on wheelchair seating systems have been conducted, it seems that the aspect of aforementioned problems can still be further improved. For reduce the risks of back pain, pressure ulcers, and decreased pulmonary function in wheelchair sitting posture. This study proposed a novel wheelchair seating system concept: the backward thoracic with upward femur support seating system. The purpose of this study was to evaluate the spinal angle, back muscle activation, interface pressure, pulmonary function, and subjective discomfort when using the backward thoracic with upward femur support seating system in the elderly population. Twenty elderly people were recruited for this study. the backward thoracic with upward femur support sitting (TF) was compared with the relaxed slouching sitting (RS), flat back support sitting (FB), prominent lumbar support sitting (PL), and backward thoracic support sitting (BT). Spinal angle (thoracic, lumbar, and pelvic angles), back muscle activation (maximal voluntary isometric contraction of the thoracic erector spinae at T9, iliocostalis lumborum pars thoracis, lumbar erector spinae, and lumbar multifidus on both sides), interface pressure (total contact area, average pressure, and peak pressure on backrest and seat), pulmonary function (forced vital capacity, forced expiratory volume in 1 second, and peak expiratory flow), and subjective discomfort (neck, shoulder, upper-back, mid-back, lower-back, upper-arm, lower-arm, buttock, thigh, and leg) were measured and compared. The results of spinal angle measurement: the TF showed relatively higher thoracic kyphosis and lumbar lordosis when compared with the RS, FB and PL, no significant difference when compared with the BT; and it also showed a relatively neutral pelvic tilt when compared with the RS and LP, no significant difference was observed when compared with the FB and BT. The results of back muscle activation measurement: the TF showed relatively higher back muscle activity when compared with RS and lower back muscle activity when compared with the FB and PL in all tested muscles, no significant differences when compared with the BT. The results of interface pressure measurement: the TF showed relatively higher total contact area, average pressure and peak pressure on backrest when compared with the other sitting postures; and the BT showed relatively lower average pressure and peak pressure on seat when compared with the other sitting postures; nevertheless, the TF showed relatively lower total contact area, average pressure, and peak pressure on the back part of seat and higher total contact area, average pressure, and peak pressure on the front part of seat when compared with the BT. The results of pulmonary function test: the TF showed relatively higher pulmonary function values when compared with the RS, FB, and PL in all tested parameters, no significant differences were observed when compared with the BT. The results of subjective discomfort evaluation: the TF showed relatively lower subjective discomfort in upper-back, mid-back, and lower-back when compared with the RS, FB, and PL, no significant difference when compared with the BT; and it also showed relatively lower subjective discomfort in buttock and higher subjective discomfort in thigh when compared with other sitting postures. The backward thoracic with upward femur support seating system concept was suggested because it maintains an increased lumbar lordosis with rather neutral pelvic tilt, decreased back muscle activation, diminished pressure on the ischial tuberosities, improved pulmonary function, and lessened subjective discomfort in back and buttock which may help maintains a better wheelchair sitting posture for reduce the risks of back pain, pressure ulcers, and pulmonary function decline. The achievements of this study contribute to the decision-making processes of wheelchair seating systems for consumers, clinicians, and manufacturers.

碩士
國立成功大學
醫學工程研究所
87
Abstract Following with the melioration of medical and engineering technology, its to attach importance to welfare and living quality of deformity; The ultimately purpose of rehabilitated medicine is to improve the functional development of deformities. In Taiwan, the cerebral palsy have often developmental delay, deformity, and functional disabilities resulting from abnormal muscle tone, reflex and impaired sensory system. Early intervention for C.P. initiating from 2 to 3 years old, who have received early rehabilitation treatment, seating and body supports with assistant technology as well as long-term training and education, has demonstrated to provied promising outcomes in significantly improved abnormal muscle tone, reflex, bodys coordination and balanced control. Unfortunately, there is lack of assistive technology service program to provide systematical clinical evaluation and prescription of specialized seating / positioning support systems for the neuromuscular impairment in Taiwan. In addition, the fields of rehabilitation technology/assistive devices are very new with little R&D. This project is to design specialized seating/positioning wheelchair for the cerebral palsied. The goal is to provide clinical effective seating supports for minimizing abnormal muscle tone and reflex, and to improve balance control, movement coordination and functional activities for the cerebral palsied. This project select 93 cerebral palsied, measuring the anthropometric data of optimized seating position. Using Multivariate Cluster Analysis to divide subjects into two clusrters, according to ages 2~8 and 9~26. Then using Univariate Regression Analysis to predict the range of anthropometric data in which two clusters. In order to target the modular dimension of the wheelchair main structure, therefore to follow the example of case numbers, to select in each division and to decide the standard dimension of seating anthropometric, at the same time to transfer variance into wheelchair’s main structure and to proceed conceptual design. The project using AutoCAD to draw wheelchair dimension plane and three-D conceptual drawing. Using spacilized CAD/CAM software Pro/Engineer to simulate actual wheelchair specification and to compute the center of gravity position and inertia tensor of wheelchair structure. The results of this project indicate that the center of gravity position locate upon the center axis of cross bar, underscoring the seating system. Conforming to safety designing condition; the next, in all direction of inertial tensor respect to wheelchair are greater than tensors of plane. It means that the motion of wheelchair will be slower when it turning around. In the other hand, it will be more laborions when family members moving wheelchair. In view of obvious variabilitiy between each cerebral palsy. The design of individual seating and positioning wheelchair must to be base on biomechanics, posture controling, neuropathology, human factor engineering, to investigate objective clinical evaluation, to provide effective personal deficient device. Final destination of this research are (1) Keeping normal posture control and bring to maximum regular function. Promoting the patient independent ability. (2) Providing clinical training and collecting the data auxiliaryequipment(3) Training engineers to design and manufacture seating and positioning body support. (4) Shifting technology to medical treatment system. Developing science and technology about auxiliaryequipment.

碩士
國立成功大學
醫學工程研究所
89
In addition to medical and rehabilitative treatments, seating/positioning is important to the individual with central nervous deficits, particularly for moderate or severe cerebral palsied (CP) children. It has been reported statistically in Taiwan that 0.6 to 5.9 per 1,000 children are affected by CP. Proper seating and body support devices are useful in normalized muscle tone, decreasing the influence of pathological reflex and improving body stability and movement for preventing deformities, developmental delays and functional disabilities from their life span. This research purpose was to develop a modular design of specialized wheelchair (WC) and support systems for effectively customized fitting the individual’ seating/positioning needs, and for minimizing the product design and manufacturing cost. More specifically, this research was to: (1) develop and establish modular parameters of mechanical structure, mechanics and components for the design specification of specialized WC and body support system; (2) apply CAD/CAM and finite element method (FEM) for mechanical design, stress and strain analysis of structural and mechanic components, and manufacturing of modular products. The modular design of seating/positioning devices has been motivated from wide variations of age, body sizes, neuromuscular impairments and functional support needs for the CP population. The seat width and depth, backrest height and leg length, seat and back angles, and other components’ dimensions in linear and angular ranges need to be considered in the design of specialized WCs with foldable, anti-tip and braking functions. The design of body supports needs consider the size, shape and fitting location of head and trunk supports, H hardness and safety belts, abductor and tray. In Stage I, the main structural parameters of WC’ seat width and depth, backrest height and legrest length for modular design specifications were determined from Average Linkage and K-means methods of multivariable cluster analysis on the anthropometrics data measured and collected from 140 CP cases (ranging from 2 to 25 years old). The dimensional ranges of other components and body support systems were also statically determined from the subject’ database for modular design specifications. In Stage II, SolidWorks packages with constructive solid geometry of pipe, beam and shell components and triangular elements of FEM with strength analyses of maximum shear stress criterion were used for CAD design and stress-strain analysis of the structural and mechanic components and modular parts of the special wheelchair with A6061T6 aluminum alloy tubing and plate. In Stage III, CAM was used for the manufacturing and dies molding and assembly of the modular design products. The R&D has completed 3 prototype design modules of large, medium and small folding and reclining WCs equipped with anti-tip and brake devices for safety, the dimensional options include: 25.4, 31.8 and 41.4cm for WC width; 18, 21, 26, 31, 36, 41, 47, 51 and 56cm for both WC depth and backrest height; 15, 21, 27, 33, 39 and 44cm for legrest length; 5, 8 and 12 for seat angle; 75, 85 and 95mm in radius curve for head support; 40 and 65mm height for trunk support; and 60, 80 and 100mm width for abductor. All parts and components are easily inserted and removed adjustably to fit each individual needs. A seating/positioning protocol has been developed for clinical evaluation, measuring, prescription and fitting of the specialized WC and body supports. Fifty cases with severe cerebral palsy have been prescribed and fitted with their appropriate WCs and supports with the assembly of developed modular components according to their individuals’ needs. This pilot field testing of clinical application has demonstrated that the modular design of wheelchair and seating/positioning supports is useful to provide effective mobility aids, normalized muscle tone, body alignment and postural control , and to improved the influence of reflex, body coordination, balanced and movement, and functional abilities. The『Modular Design』seems to be highly applicable to satisfy widely varied seating/positioning needs for the CP, SCI, Strokes, TBI, MD and MS. In addition, the design and manufacturing process can be achieved with significantly minimized the product cost for wheelchair industries. Further clinical studies for application outcomes need to be investigated.

The limited customisation in commercially available wheelchairs does not always appropriately accommodate the anthropometric variations resulting from specific impairment. Wheelchair racing athletes demonstrate up to 3.8% total body mass greater in the upper extremities, and up 9.8% total body mass reductions in their lower extremities, and between-limb asymmetries of 62.4%. As a consequence, athletes may not have the stable base of support required for optimal propulsion. The optimisation of an entire wheelchair to match unique athlete geometry is both time consuming and costly, as wheelchairs cost over $2000 each. The use of assistive technology can provide an efficient transition between the commercially available equipment and the unique athlete anthropometry. Customised seating interfaces offer a time and cost effective solution, facilitating regular modifications to satisfy athlete growth. These solutions have been used extensively in clinical applications for enhanced stress distribution and injury prevention at the seating interface; however, they have not yet been applied to sporting contexts. The goal of this research was to investigate the performance impact of customised seating interfaces on wheelchair racing propulsion technique. Supplementary goals included the development of practically viable instrumentation solutions and a musculoskeletal model representative of the unique wheelchair racing athlete anthropometries and physical capabilities to assess injury risk to analyse performance impact holistically. The research was split into four main themes: 1. Verification of the importance of the seating interface relative to other key performance parameters such as aerodynamics and glove selection. 2. Instrumentation of the hand-pushrim and seating interfaces 3. Development of a musculoskeletal model 4. Computational modelling of performance and injury risk Computational modelling was performed in the OpenSim environment which coupled kinematic inputs from 3D motion capture (VICON Bonita V16; Oxford Metrics, Oxford, United Kingdom), with kinetic inputs from a pressure mat at the seating interface (XSensor LX100; Calgary, Alberta, Canada) and inertial measurement units (IMUs) (I Measure U; New Zealand) to estimate the hand-interface interactions. This was achieved using Newton’s Second Law, incorporating athlete-specific mass data (from the analysis DXA scans), and acceleration measured from the IMU. Customised seating interfaces reduced the undesirable peak translations of the knee by up to 41.8% and lateral translation of the spine by 33.4%. These translated towards enhanced performance, with an average performance time reduction of 29.8 s (3.7% race time) in the eight international competitions following the inclusion of the customised seating interface. Additionally, athletes using cushioned seating interfaces had reduced peak pressures at the seating interface as compared to those without the interface. Instrumentation can be used outside the laboratory environments, and can, therefore, be applied in the daily training environment to optimise performance preparation. This research provided foundation work for the use of computational biomechanical analyses for the holistic assessment of wheelchair racing performance. Whilst this research has demonstrated the potential impact computational modelling approaches can have on the performance preparation of athletes, some areas for further refinement have been identified. Future research into the processing of IMU data and the validation of musculoskeletal models for wheelchair racing athletes are the critical areas for improvement. Once achieved, the computational modelling approaches explored in this research can positively impact performance outcome, particularly when coupled with the optimisation of equipment, such as customised seating interfaces.
Thesis (Ph.D.) -- University of Adelaide, School of Mechanical Engineering, 2019

Participants in the author’s training program for OT practitioners who work in skilled nursing facilities will gain an understanding of the need and requirements for ongoing wheelchair seating and positioning management of long-term care residents. BACKGROUND: Elderly individuals admitted to a skilled nursing facility receive initial occupational therapy (OT) evaluation for appropriate wheelchair (WC) seating. On extended stay, the resident’s seating needs often change, leading to postural impairment from improper positioning. Lack of awareness of poor positioning by residents, particularly when cognitive issues are present, can delay corrective action because they may not call attention to difficulties or discomfort. Occupational therapy practitioners (OTPs) can play a distinctive role in ensuring that proper wheelchair seating and positioning of older residents is maintained. The author’s aim is to create a prototype program designed to mitigate the risk that accompanies poor wheelchair positioning and that can be carried out at any skilled nursing facility (SNF). OBJECTIVES: The author’s project will address the recognized need for a training program for occupational therapy practitioners that will provide guidelines for assessing, evaluating and planning the appropriate intervention for an elderly manual wheelchair user in a skilled nursing facility. Objectives for the resident include reduction in the incidence of wound development, improvement of functioning, and increase in participation in the care environment with other wheelchair users. METHOD: Program implementation will begin with facility recruitment. The author will create a handout illustrating the planned program and will distribute it in person or via mail to administrators of skilled nursing and residential care facilities within a 100-mile radius that have a rehabilitation department and one or more OT practitioners. When interest is expressed by a recipient, the author will contact the facility and conduct a short interview to discuss problems and concerns, the availability of staff incentives for participation in inservice training, and payment for the author’s services. Depending upon the author’s assessment of participant knowledge, skills and needs, training will be adjusted from an introductory to intermediate level. As part of the proposed program, the author will recommend that OT practitioners instruct nursing and other caregiving staff to periodically screen every wheelchair-dependent resident when they are providing direct care during their daily routines. Miller, Miller, Trenholm, Grant and Goodman (2004) developed the Seating Identification Tool (SIT) to fill the need for an easy to administer screening questionnaire that would be sufficiently sensitive for clinical assessment and research. ANTICIPATED FINDINGS: Occupational therapy practitioners will play a distinctive role in ensuring that proper wheelchair seating and positioning of older residents is maintained. Preventing pressure ulcers will prove to be much less costly than medical treatment, both to the resident and the facility. Reduction in time lost from daily occupations to allow healing will improve the client’s sense of well-being. OT practitioners will be called upon to make periodic adjustments in wheelchair fitting and positioning, which might as simple as providing an appropriate wheelchair cushion. LIMITATIONS: Program development and program evaluation research are in the initial stages and have not yet been implemented in any skilled nursing facility. RECOMMENDATIONS: The author recommends implementation of the pilot program in a skilled nursing facility with data gathering for program evaluation research to gain evidence and further refine the program.

In British Columbia (BC), people with developmental disabilities, including those with severe physical impairments, have left institutions to live in supported homes in the community. Services traditionally provided in the institution, up until final closure in 1996, are now provided in community. One of the necessary, specialized community services identified during the final deinstitutionalization phase from 1990 to 1996 was therapeutic wheelchair positioning or 'seating'. In 1996, a study was contracted by the Transition Steering Committee (TSC), a group responsible for ensuring the availability of services in the community for persons leaving institutions. The study defined the need for seating services, determined client and therapist preferences and reviewed existing seating resources, in order to develop a workable service delivery model for adults with developmental disabilities in B C . The model conceived in 1997, but never implemented, was that of a boundaryless service network termed the British Columbia Seating Network (BCSN). In order to understand the context of community living service development for this population (including barriers to implementation of new programs) as well as to confirm that the proposed model of service delivery still satisfied the prospective users of the BCSN, qualitative investigative activities were undertaken. Following from the research of the original project, three key stakeholder groups were identified - consumers, community therapists and provincial government administrators. The perspective of the consumer was investigated through an interview with the executive director of the British Columbia Association for Community Living (BCACL); community therapists attended focus groups; and relevant government administrators, including members of the TSC, were interviewed about the deinstitutionalization experience in B C , as well as the status of evolving community living services, including the proposed BCSN. Results indicated that, while most participants believed that deinstitutionalization had been an overall success, there were many challenges facing community living services, and the determinants to success or failure were often political in nature. Participants collectively praised the BCSN, yet analysis of findings indicated that the model was ultimately doomed to failure because of poor timing, lack of profile or of a champion, an all or nothing approach which encompassed a preference for generic over specialized service, sustainability, the tenuous relationship between research and policymaking, the destabilizing effect of change, as well as other influential aspects of the political decision-making process during the final stages of deinstitutionalization. Other themes which arose out of the findings included the fear of reinstitutionalization, the lack of planning for aging in place and for new users of community living services, and the pivotal and evolving role of interest groups. Finally, a future focus for stakeholders in community living in B C was articulated as ensuring that families in community would not be forgotten because the high profile that deinstitutionalization had given persons with developmental disabilities was gone. It was concluded that the B C S N was the right model, but that political barriers had ultimately prevented implementation, and that all stakeholders in community living need to be aware of the multiple and complex influences contributing to decision-making around the development of health services for persons with developmental disabilities.

University of Technology, Sydney. Faculty of Engineering and Information Technology.
NO FULL TEXT AVAILABLE. This thesis contains 3rd party copyright material. The hardcopy may be available for consultation at the UTS Library.
NO FULL TEXT AVAILABLE. This thesis contains 3rd party copyright material. ----- More often than not, impaired mobility results in fewer opportunities for socialising, and pursuing personal goals and pursuits. This can produce depression, anxiety and social isolation for physically impaired people. As an aid to mobility, an electric-powered wheelchair can assist a disabled person in improving their quality of life. The safe control of a conventional powered wheelchair nevertheless requires a significant level of skill, attention, judgment and appropriate user response. Like an automobile user, a wheelchair user may also encounter an accident and injury. To safely and comfortably accommodate a powered wheelchair user, there has been great advancement in recent decades in the development of autonomous and semiautonomous powered wheelchairs. However, the majority of this research focus on a supervisory control level related to developing navigation algorithms, shared-control approaches, and hand-free control strategies. Due to parameter uncertainties and external disturbances, an optimal performance and overall system robustness depends heavily on the low control level involved in precision motion control. Surprisingly, there is still very little research into control techniques for this level. Although many advanced control techniques have been developed for the low level control, none of these techniques are expected to be optimal. This is largely because they have not treated the powered wheelchair as a multivariable system. Due to interactions between different inputs and outputs, a control design task for a multivariable system can also be complicated. Some very effective solutions for the inherent issues pertaining to multivariable systems involve decoupling techniques. These endeavour to simplify a multivariable control problem through reduction to a series of scalar control problems. However, there is still a scarcity of research regarding robustness under effects of uncertainty and external disturbance. In this thesis, a combination of decoupling techniques and advanced control strategies leads to three new advanced multivariable control approaches. These approaches offer systematic solutions for problems of precision motion control in the low control level of a wheelchair system. New multivariable control approaches reduce a multivariable control problem into a series of scalar control problems, as such they have the advantage of involving less complexity and computation. Based on an identification framework, an approximate dynamic multivariable model is generated for a powered wheelchair to facilitate control implementation. The first multivariable control approach is derived from a combination of a Triangularization technique and a Model Predictive Control strategy. This approach can guarantee an optimal performance for a linear dynamic multivariable system. Apart from providing a systematic solution for a linear multivariable system, this approach also handles control problems naturally, takes into account of actuator limitations, and allows operation closer to constraints. Real-time implementation indicates the effectiveness of this approach for the powered wheelchair. The second multivariable control approach is derived from a combining a Triangularization technique and Optimal Neural Network Control strategy. This new approach guarantees the optimal performance for a dynamic multivariable system against parameter uncertainties. Experiment results related to path-following control of the powered wheelchair system reveal that, regardless of parameter uncertainty effects, this second multivariable control approach considerably improves system performance, robustness, and accuracy, in comparison with various popular control approaches. The results also demonstrate that coupling effects in the wheelchair dynamics are substantially reduced. The third multivariable control approach is derived from the combination of Diagonalization technique and Robust Neuro-Sliding Mode Control strategy. This novel approach can effectively cope in real time with parameter uncertainties and external disturbances to achieve robustness and a desired performance for a multivariable system. This third approach fully reduces the coupling effects on a multivariable system, eliminates the chattering phenomena, and avoids plant Jacobian calculation. Furthermore, it can also achieve fast and global convergence with less computation. The effectiveness of this novel approach has been verified through real-time implementation of the powered wheelchair system. The results guarantee robustness and desired performance of the overall system, even with the compounding effect of parameter uncertainties and external disturbances.

碩士
長庚大學
醫療機電工程研究所
95
Autonomous robotic wheelchairs are widely discussed in recent years. Most of autonomous robotic wheelchairs were developed based on rich computation architecture to deal with complicated navigation efforts such as personal computers or embedded computers. However, such rich computation architectures increase cost of robotic wheelchair when compared to conventional powered wheelchairs. At the same time, large amounts of energy consumptions, lower reliability, and inefficient size of personal computers reduce the practicability of robotic wheelchair. In this paper, we present a low cost chip based solution to solve complicated wheelchair navigation problem based on distributed computing architecture. This solution is developed based on the programmable System-on-Chip (PSoC) computing and control architecture. The tasks within autonomous navigations are categorized into human machine interface, sensor collection, fuzzy logic based navigation functions, closed loop motion controller, and these tasks are individually implemented using the PSoC. Finally, the task oriented PSoC are integrated and fused to perform autonomous navigations of robotic wheelchairs. Consequently, the proposed PSoC based distributed computing architecture was successfully implemented and experimentally tested. The navigation results were verified using the results inferred from personal computer based computing architectures.

University of Technology, Sydney. Faculty of Engineering and Information Technology.
This thesis investigates High Frequency Radio Frequency Identification (HF RFID) based positioning using a novel concept of multi-loop bridge reader antenna to localise moving objects such as autonomous wheelchairs in indoor environments. Typical HF RFIDs operate at 13.56 MHz and employ passive tags which are excited by the magnetic field radiated by the reader antenna. Positioning of moving objects using HF RFID systems derive location information by averaging the coordinates of detected passive floor tags by a portable reader antenna which are then recorded in the reader’s memory and database. To successfully detect floor tags, the reader’s antenna usually installed at the base of a moving object needs to be parallel to the floor. The magnetic field radiated by the HF RFID antenna is confined within its near field zone i.e., it is confined to a very close proximity of the antenna. This property of HF RFID helps to minimise interference to other appliances that may be present within the localisation area. Thus, HF RFID based positioning offers great potential benefit in providing location assistance in environments such as nursing homes, health care facilities, hospitals etc. However, despite the significant developments that have occurred in this field, there still exist problems with positioning accuracies obtainable mainly due to the uncertainty of the reader recognition area (RRA) of the reader antenna, which has not been fully addressed in literature. This thesis aims to address this problem by proposing the concept of multi-loop bridge reader antenna so that the reader recognition area is divided into multiple sub zones and an error signal (bridge signal) in terms of the position of the tag will be generated that helps to reduce the position uncertainty. The thesis starts with an investigation of the methods for creating multiple zones of RRA and the concept of bridge loop antenna from point of view of near magnetic fields. Different types of loop antennas for employing at the reader are electromagnetically analysed using both closed form solutions and numerical computations. The formation of reader recognition area (RRA) from different arrangements of loop reader antennas is also studied. To ensure that proposed bridge antennas can perform in realistic, non-ideal indoor environments where they are affected by proximity of metallic objects etc, we proposed methods of improvement. Equivalent circuits that reduce the computational complexity but can provide a broader understanding of the behaviour of bridge antennas have been formulated. This has lead to investigation of methods to minimise and/or eliminate the effect of metallic objects on the bridge signals. Next, we investigate the applicability of the proposed bridge loop antenna for the localisation and positioning of an autonomous wheel chair resulting in a realistic implementation of HF RFID based positioning system. The system is then tested to localise an autonomous wheelchair in an indoor environment using a grid of passive floor tags. Novel algorithms are proposed to estimate the position and orientation of the moving object using bridge signals generated by the bridge antenna coupled with the available dynamic information of the wheelchair. A comparison of our experimental results with the published results in the literature revealed significant improvements achieved by our proposed methods over existing techniques for estimating both, the orientation and position. Further, we demonstrate that the proposed technique obtains accurate position and estimation using much lesser number of floor tags (increased sparcity) than any of the currently published method, thus, contributing to simplified and easily expandable tag infrastructure deployment. We further extend the use of bridge loop antenna for situation when multiple tags are detected using the method of load modulation of the tags. When multiple tags present within the RRA of the bridge loop antenna, the resulting bridge signals incorporate information from all of the detected tags thus making it difficult to locate individual tags. To overcome this, we utilise states of the tag’s load modulation to separate these bridge signals, which then allow us to utilise them to estimate instantaneous position and orientation of the moving object. We performed analysis using equivalent circuits, as well as computational electromagnetic modelling of realistic antennas, which are then compared with experimental measurements carried on prototype systems. The comparison showed good agreement which validate our proposed method. Thus, the thesis incorporate contributions on various aspects of bridge loop reader antenna for HF RFID based positioning system. All full wave electromagnetic computations and simulations were carried by using a well known antenna design package “FEKO”. All the key analyses, equivalent circuits, antenna models and computational results for the proposed antennas and algorithms have been verified using extensive experimental campaigns to demonstrate the practical usefulness of the proposed methods. It is hoped that the findings in this thesis will result in newer efficient positioning systems in future.