Design, implementation, control, and user evaluations of assiston-arm self-aligning upper-extremity exoskeleton

Physical rehabilitation therapy is indispensable for treating neurological disabilities. The use of robotic devices for rehabilitation holds high promise, since these devices can bear the physical burden of rehabilitation exercises during intense therapy sessions, while therapists are employed as decision makers. Robot-assisted rehabilitation devices are advantageous as they can be applied to patients with all levels of impairment, allow for easy tuning of the duration and intensity of therapies and enable customized, interactive treatment protocols. Moreover, since robotic devices are particularly good at repetitive tasks, rehabilitation robots can decrease the physical burden on therapists and enable a single therapist to supervise multiple patients simultaneously; hence, help to lower cost of therapies. While the intensity and quality of manually delivered therapies depend on the skill and fatigue level of therapists, high-intensity robotic therapies can always be delivered with high accuracy. Thanks to their integrated sensors, robotic devices can gather measurements throughout therapies, enable quantitative tracking of patient progress and development of evidence-based personalized rehabilitation programs. In this dissertation, we present the design, control, characterization and user evaluations of AssistOn-Arm, a powered, self-aligning exoskeleton for robotassisted upper-extremity rehabilitation. AssistOn-Arm is designed as a passive back-driveable impedance-type robot such that patients/therapists can move the device transparently, without much interference of the device dynamics on natural movements. Thanks to its novel kinematics and mechanically transparent design, AssistOn-Arm can passively self-align its joint axes to provide an ideal match between human joint axes and the exoskeleton axes, guaranteeing ergonomic movements and comfort throughout physical therapies. The self-aligning property of AssistOn-Arm not only increases the usable range of motion for robot-assisted upper-extremity exercises to cover almost the whole human arm workspace, but also enables the delivery of glenohumeral mobilization (scapular elevation/depression and protraction/retraction) and scapular stabilization exercises, extending the type of therapies that can be administered using upper-extremity exoskeletons. Furthermore, the self-alignment property of AssistOn-Arm signi cantly shortens the setup time required to attach a patient to the exoskeleton. As an impedance-type device with high passive back-driveability, AssistOn- Arm can be force controlled without the need of force sensors; hence, high delity interaction control performance can be achieved with open-loop impedance control. This control architecture not only simpli es implementation, but also enhances safety (coupled stability robustness), since open-loop force control does not su er from the fundamental bandwidth and stability limitations of force-feedback. Experimental characterizations and user studies with healthy volunteers con- rm the transparency, range of motion, and control performance of AssistOn- Ar

Development and testing safe fall strategies for lower limbs exoskeletons

Loss of mobility is among the most impactful consequences of sustaining a spinal cord injury. Wheelchairs provide a considerable degree of mobility to their users, but are not without their drawbacks, most of which are caused by requiring prolonged periods of time in the sitting position. Recently, the field of lower limb exoskeletons has seen considerable developments, and the use of external power technologies has made it possible for users to walk for longer periods of time. However, current exoskeletons do not ensure balance during standing and walking conditions, which leaves their users vulnerable to situations of instability and falls. The goal of this thesis was to investigate safe fall strategies to reduce the severity of the impact in case of a loss of balance with a lower limb exoskeleton. The backwards fall scenario is examined, and a fall strategy is implemented in a simulation environment, using a combination of center of mass and hip joint angle reference signals. The results verified the model’s ability to execute the proposed strategy by following the reference signals, and the strategy was shown to result in safer falls. Further work should be conducted to test this strategy in real-life human-exoskeleton fall scenarios, and to develop strategies for other fall scenarios.Perda de mobilidade é das consequências com maior impacto na vida de quem sofre uma lesão da medula espinhal. Cadeiras de rodas providenciam um nível considerável de mobilidade aos seus utilizadores, mas trazem os seus próprios problemas, sendo que a maioria dos quais são resultantes da necessidade dos seus utilizadores permanecerem sentados durante longos períodos de tempo. Mais recentemente, a área dos exosqueletos para membros inferiores tem visto desenvolvimento notável, e o uso de fontes de energia externas tem permitido que os seus utilizadores se desloquem a pé durante intervalos de tempo maiores. Contudo, estas tecnologias ainda não garantem equilíbrio constante dos seus utilizadores durante a marcha ou em pé, o que faz com que estes estejam vulneráveis a situações de instabilidade e quedas. Esta tese teve como objetivo investigar estratégias de queda segura para reduzir a severidade do impacto em caso de uma perda de equilíbrio utilizando um exosqueleto para membros inferiores. É examinado o cenário de uma queda para trás, e é implementada uma estratégia de queda num ambiente de simulação, recorrendo a uma combinação de sinais de referência de centro de massa e ângulo da articulação da anca. Os resultados verificaram a capacidade do modelo utilizado executar a estratégia proposta ao seguir os sinais de referência, e a estratégia mostrou resultar em quedas mais seguras. No futuro, a estratégia deve ser testada em cenários reais de quedas de um exosqueleto e o seu utilizador, e devem ser desenvolvidas estratégias para os restantes cenários de queda

Design, implementation and control of self-aligning, bowden cable-driven, series elastic exoskeletons for lower extremity rehabilitation

We present AssistOn-Leg, a modular, self-aligning exoskeleton for robotassisted rehabilitation of lower extremities. AssistOn-Leg consists of three selfaligning, powered exoskeletons targeting ankle, knee and hip joints, respectively. Each module can be used in a stand-alone manner to provide therapy to its corresponding joint or the modules can be connected together to deliver natural gait training to patients. In particular, AssistOn-Ankle targets dorsiflexion/ plantarflexion and supination/pronation of human ankle and can be configured to deliver balance/proprioception or range of motion/strengthening exercises; AssistOn-Knee targets flexion/extension movements of the knee joint, while also accommodating its translational movements in the sagittal plane; and AssistOn- Hip targets flexion/extension movements hip joint, while allowing for translations of hip-pelvis complex in the sagittal plane. Automatically aligning their joint axes, modules of AssistOn-Leg ensure an ideal match between human joint axes and the exoskeleton axes. Self-alignment of the modules not only guarantees ergonomy and comfort throughout the therapy, but also significantly shortens the setup time required to attach a patient to the exoskeleton. Bowden cable-driven series elastic actuation is utilized in the modules located at the distal (knee and ankle) joints of AssistOn-Leg to keep the apparent inertia of the system low, while simultaneously providing large actuation torques required to support human gait. Series elasticity also provides good force tracking characteristics, active back-driveability within the control bandwidth and passive compliance as well as impact resistance for excitations above this bandwidth. AssistOn-Hip is designed to be passively back-driveable with a capstan-based multi-level transmission. Thanks to passive compliance of the distal modules and passive backdriveability of the hip module, the overall design ensures safety even under power losses and robustness throughout the whole frequency spectrum

Advanced technology for gait rehabilitation: An overview

Most gait training systems are designed for acute and subacute neurological inpatients. Many systems are used for relearning gait movements (nonfunctional training) or gait cycle training (functional gait training). Each system presents its own advantages and disadvantages in terms of functional outcomes. However, training gait cycle movements is not sufficient for the rehabilitation of ambulation. There is a need for new solutions to overcome the limitations of existing systems in order to ensure individually tailored training conditions for each of the potential users, no matter the complexity of his or her condition. There is also a need for a new, integrative approach in gait rehabilitation, one that encompasses and addresses all aspects of physical as well as psychological aspects of ambulation in real-life multitasking situations. In this respect, a multidisciplinary multinational team performed an overview of the current technology for gait rehabilitation and reviewed the principles of ambulation training

Lower limb exoskeleton robot and its cooperative control: A review, trends, and challenges for future research

Effective control of an exoskeleton robot (ER) using a human-robot interface is crucial for assessing the robot's movements and the force they produce to generate efficient control signals. Interestingly, certain surveys were done to show off cutting-edge exoskeleton robots. The review papers that were previously published have not thoroughly examined the control strategy, which is a crucial component of automating exoskeleton systems. As a result, this review focuses on examining the most recent developments and problems associated with exoskeleton control systems, particularly during the last few years (2017–2022). In addition, the trends and challenges of cooperative control, particularly multi-information fusion, are discussed

Ekonomicky dostupný aktivní exoskeleton pro dolní končetiny pro paraplegiky

After a broad introduction to the medical and biomechanical background and detailed review of orthotic devices, two newly developed lower limbs exoskeletons for paraplegics are presented in this study. There was found out the main challenges of designing devices for paraplegic walking can be summarized into three groups, stability and comfort, high efficiency or low energy consumption, dimensions and weight. These all attributes have to be moreover considered and maintained during manufacturing of affordable device while setting a reasonable price of the final product. A new economical device for people with paraplegia which tackles all problems of the three groups is introduced in this work. The main idea of this device is based on HALO mechanism. HALO is a compact passive medial hip joint orthosis with contralateral hip and ankle linkage, which keeps the feet always parallel to the ground and assists swinging the leg. The medial hip joint is equipped with one actuator in the new design and the new active exoskeleton is called @halo. Due to this update, we can achieve more stable and smoother walking patterns with decreased energy consumption of the users, yet maintain its compact and lightweight features. It was proven by the results from preliminary experiments with able-bodied subjects during which the same device with and without actuator was evaluated. Waddling and excessive vertical elevation of the centre of gravity were decreased by 40% with significantly smaller standard deviations in case of the powered exoskeleton. There was 52% less energy spent by the user wearing @halo which was calculated from the vertical excursion difference. There was measured 38.5% bigger impulse in crutches while using passive orthosis, which produced bigger loads in upper extremities musculature. The inverse dynamics approach was chosen to calculate and investigate the loads applied to the upper extremities. The result of this calculation has proven that all main muscle groups are engaged more aggressively and indicate more energy consumption during passive walking. The new @halo device is the first powered exoskeleton for lower limbs with just one actuated degree of freedom for users with paraplegia.První část práce je věnována obsáhlému úvodu do zdravotnické a biomechanické terminologie a detailnímu souhrnnému představení ortopedických pomůcek. Následně jsou představeny dva nově vyvinuté exoskelety aplikovatelné na dolní končetiny paraplegiků. Bylo zjištěno, že hlavní úskalí konstrukčního návrhu asistenčních zařízení pro paraplegiky lze shrnout do tří hlavních skupin, jako první je stabilita a komfort, druhá je vysoká účinnost a nízká energetická náročnost uživatele a do třetí lze zahrnout rozměry a hmotnost zařízení. Toto všechno je navíc podmíněno přijatelnou výslednou cenou produktu. Nový ekonomicky dostupný exoskelet pro paraplegiky, který řeší problematiku všech tří zmíněných skupin je představen v této práci. Hlavní myšlenka tohoto zařízení je postavena na mechanismu HALO ortézy. HALO je kompaktní pasivní ortéza s mediálním kyčelním kloubem umístěným uprostřed mezi dolními končetinami. Speciální mediální kyčelní kloub je kontralaterálně propojen s kotníkem soustavou ocelových lanek což zajištuje paralelní polohu chodidla se zemí v každém okamžiku chůze a navíc asistuje zhoupnutí končetiny. Tento mediální kyčelní kloub je redesignován a v novém provedení je vybaven jedním aktuátorem, nové řešení aktivního exoskeletu dostalo název @halo. Díky tomuto vylepšení lze dosáhnout stabilnější a plynulejší chůze s výrazně redukovanou energetickou náročností uživatele přičemž dochází k zachování nízké hmotnosti a kompaktnosti zařízení. Toto bylo dokázáno během předběžných experimentů se zdravými subjekty, během kterých byla testována aktivní chůze se zařízením vybaveným odnímatelnou pohonnou jednotkou a pasivní chůze se stejným zařízením bez této aktivní jednotky. Nadměrné naklánění se během chůze ze strany na stranu a nadměrná výchylka pohybu těžiště těla ve vertikálním směru byly sníženy o necelých 40% s velmi významně menšími standardními odchylkami v případě chůze s pohonem. Z rozdílu výchylky pohybu těžiště těla ve vertikální poloze bylo vypočítáno snížení energetické náročnosti uživatele o 52% při chůzi s aktivní konfiguraci @halo. Při pohybu s pasivní ortézou byl naměřen o 38,5% větší reakční silový impuls v berlích, což znamená nárůst zátěže pro svalový aparát horních končetin. Pro podrobné vyšetření zátěže ramenních kloubů byl aplikován model inverzní dynamiky. Výsledek tohoto výpočtu jednoznačně indikuje agresivnější a hlubší zapojení všech svalových skupin ramenního kloubu a tím vyšší spotřebu energie uživatelem během pasivní chůze. Nové asistenční zařízení @halo je prvním exoskeletem svého druhu pro paraplegiky s jediným poháněným stupněm volnosti.354 - Katedra robotikyvyhově