Thesis (B.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1982. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING / Bibliography: leaf 60. / by Susan Russell Stapleton. / B.S.

Repair and remodeling of bone during healing and fusion require a combination of bone resorption and formation to successfully restore the bone to its previous strength. The healing process is highly responsive to the mechanical conditions of the construct, where excessive loading can cause high strains that delay healing, but moderate loading can be beneficial. Maintaining compression at the site of fracture can benefit healing by maintaining bone congruency and increasing the stability of the bone-implant construct to prevent excessive shifting. For these reasons, compressive mechanisms are employed in many orthopaedic devices, including both intramedullary (IM) nails and external fixators for ankle arthrodesis applications. Tibiotalocalcaneal (TTC) arthrodesis is a salvage procedure that fuses both the ankle and the subtalar joints. It has become the standard of care in ankle degeneration, which can be brought on by posttraumatic arthritis, failed total ankle arthroplasty, or diabetic conditions such as Charcot arthropathy. While current devices are effective in many cases, TTC arthrodesis procedures still incur failure rates as high as 22%, where failure of the bones to successfully fuse can result in amputation. Because bone healing relies upon bone resorption, the initial compression applied to the implanted constructs can be quickly lost, which may sacrifice the stability of the structure and delay or inhibit further healing. By employing a mechanism that can sustain compression during the bone healing process, it was possible to increase the stability of the construct even during bone resorption, minimizing the failures that still occur. The focus of this study was to determine the effects of compression on the mechanical stability of the implant-bone construct found in TTC arthrodesis. A comparison was made between the torsional stability of two currently marketed intramedullary devices, as well as a prototype IM device comprised of a nickel titanium core, designed to hold constant compression for up to 9mm of resorption. Additionally, the stability of each construct over time was evaluated by correlating bone resorption to a loss in compressive force.

M. Tech. Electrical engineering. / Discusses the process of standing from a chair is the first movement to be affected by physical impairment or ageing. That justified the increase of researches around sit-to-stand movements nowadays.This thesis presents the design of a four links wearable device that can assist disable people to stand from a sitting position. The four links are joined at the ankle, the knee and the HAT (Head, Arm and Trunk) where actuators are mounted. The system is built around three controllers. The Goal Controller drives the links along their reference trajectories, the Stability Controller makes sure that the system does not collapse as it is rising, and the last controller combines the signal from the 2 first ones.The reference trajectories are obtained from data recorded from healthy people performing the movement. The main idea behind the present design is that from seat off, the floor projection of the body centre of pressure is evaluated and compared to the most stable position. The stability controller generates the torque necessary to compensate the deviation, while the third controller adjusts the level of participation of that torque to satisfy both the trajectory and the stability objectives. Similar idea was previously found in Prinz (2010).

Thesis (M.A.)--University of North Carolina at Chapel Hill, 2004. / Includes bibliographical references (leaves 132-135). Also available online (PDF file) by a subscription to the set or by purchasing the individual file.

As robots become more prevalent in our everyday lives, both in our workplaces and in our homes, it becomes increasingly likely that people who are not experts in robotics will be asked to interface with robotic devices. It is therefore important to develop robotic controls that are intuitive and easy for novices to use. Robotic hands, in particular, are very useful, but their high dimensionality makes creating intuitive human-machine interfaces for them complex. In this dissertation, we study the control of non-anthropomorphic robotic hands by non-roboticists in two contexts: collaborative manipulation and assistive robotics. In the field of collaborative manipulation, the human and the robot work side by side as independent agents. Teleoperation allows the human to assist the robot when autonomous grasping is not able to deal sufficiently well with corner cases or cannot operate fast enough. Using the teleoperator’s hand as an input device can provide an intuitive control method, but finding a mapping between a human hand and a non-anthropomorphic robot hand can be difficult, due to the hands’ dissimilar kinematics. In this dissertation, we seek to create a mapping between the human hand and a fully actuated, non-anthropomorphic robot hand that is intuitive enough to enable effective real-time teleoperation, even for novice users. We propose a low-dimensional and continuous teleoperation subspace which can be used as an intermediary for mapping between different hand pose spaces. We first propose the general concept of the subspace, its properties and the variables needed to map from the human hand to a robot hand. We then propose three ways to populate the teleoperation subspace mapping. Two of our mappings use a dataglove to harvest information about the user's hand. We define the mapping between joint space and teleoperation subspace with an empirical definition, which requires a person to define hand motions in an intuitive, hand-specific way, and with an algorithmic definition, which is kinematically independent, and uses objects to define the subspace. Our third mapping for the teleoperation subspace uses forearm electromyography (EMG) as a control input. Assistive orthotics is another area of robotics where human-machine interfaces are critical, since, in this field, the robot is attached to the hand of the human user. In this case, the goal is for the robot to assist the human with movements they would not otherwise be able to achieve. Orthotics can improve the quality of life of people who do not have full use of their hands. Human-machine interfaces for assistive hand orthotics that use EMG signals from the affected forearm as input are intuitive and repeated use can strengthen the muscles of the user's affected arm. In this dissertation, we seek to create an EMG based control for an orthotic device used by people who have had a stroke. We would like our control to enable functional motions when used in conjunction with a orthosis and to be robust to changes in the input signal. We propose a control for a wearable hand orthosis which uses an easy to don, commodity forearm EMG band. We develop an supervised algorithm to detect a user’s intent to open and close their hand, and pair this algorithm with a training protocol which makes our intent detection robust to changes in the input signal. We show that this algorithm, when used in conjunction with an orthosis over several weeks, can improve distal function in users. Additionally, we propose two semi-supervised intent detection algorithms designed to keep our control robust to changes in the input data while reducing the length and frequency of our training protocol.

Post stroke rehabilitation is effective when a large number of motor repetitions are provided to patients. However, conventional physical therapy or traditional desktop-size robot aided rehabilitation do not provide sufficient number of repetitions due to cost and logistical barriers. Our vision is to realize a wearable and functional hand orthosis that could be used outside of controlled, clinical settings, thus allowing for more training repetitions. Furthermore, if such a device can prove effective for Activities of Daily Living (ADLs) while actively worn, this can incentivize patients to increase its use, further enhancing rehabilitative effects. However, in order to provide such clinical benefits, the device must be completely wearable without obtrusive features, and intuitive to control even for non-experts. In this thesis, we thus focus on wearability, functionality, and intuitive intent detection technology for a novel hand robot, and assess its performance when used both as a rehabilitative device and an assistive tool. A fully wearable device must deliver meaningful manipulation capability in small and lightweight package. In this context, we investigate the capability of single-actuator devices to assist whole hand movement patterns through a network of exotendons. Our prototypes combine a single linear actuator (mounted on a forearm splint) with a network of exotendons (routed on the surface of a soft glove). We investigate two possible tendon network configurations: one that produces full finger extension (overcoming flexor spasticity) and one that combines proximal flexion with distal extension at each finger. In experiments with stroke survivors, we measure the force levels needed to overcome various levels of spasticity and to open the hand for grasping using the first of these configurations, and qualitatively demonstrate the ability to execute fingertip grasps using the second. Our results support the feasibility of developing future wearable devices able to assist a range of manipulation tasks. In order to further improve the wearability of the device, we propose two designs that provide effective force transmission by increasing moment arms around finger joints. We evaluate the designs with geometric models and experiment using a 3D-printed artificial finger to find force and joint angle characteristics of the suggested structures. We also perform clinical tests with stroke patients to demonstrate the feasibility of the designs. The testing supports the hypothesis that the proposed designs efficiently elicit extension of the digits in patients with spasticity as compared to existing baselines. With the suggested transmission designs, the device can deliver sufficient extension force even when the users have increased muscle tone due to fatigue. The vision of an orthotic device used for ADLs can only be realized if the patients are able to operate the device themselves. However, the field is generally lacking effective methods by which the user can operate the device: such controls must be effective, intuitive, and robust to the wide range of possible impairment patterns. The variety of encountered upper limb impairment patterns in stroke patients means that a single sensing modality, such as electromyography, might not be sufficient to enable controls for a broad range of users. To address this significant gap, we introduce a multimodal sensing and interaction paradigm for an active hand orthosis. In our proof-of-concept implementation, EMG is complemented by other sensing modalities, such as finger bend and contact pressure sensors. We propose multimodal interaction methods that utilize this sensory data as input, and show they can enable tasks for stroke survivors who exhibit different impairment patterns. We then assess the performance of the robotic orthosis for two possible roles: as a therapeutic tool that facilitates device mediated hand exercises to recover neuromuscular function, or as an assistive device for use in everyday activities to aid functional use of the hand. 11 chronic stroke (> 2 years) patients with moderate muscle tone (Modified Ashworth Scale ≤ 2 in upper extremity) engage in a month-long training protocol using the orthosis. Individuals are evaluated using standardized outcome measures, both with and without orthosis assistance. The results highlight the potential for wearable and user-driven robotic hand orthoses to extend the use and training of the affected upper limb after stroke. The advances proposed in this thesis have the potential to enable robotic based hand rehabilitation during daily activities (as opposed to isolated hand exercises with limited upper limb engagement) and over extended periods of time, even in a patient’s home environment. Numerous challenges must still be overcome in order to achieve this vision, related to design (compact devices with easier donning/doffing), control (robust yet intuitive intent inferral), and effectiveness (improved functionality in a wider range of metrics). However, if these challenges can be addressed, wearable robotic devices have the potential to greatly extend the use and training of the affected upper limb after stroke, and help improve the quality of life for a large patient population.

Robotic exoskeletons are important tools in medicine for characterizing certain aspects of diseases, enabling physical therapy treatments, or providing assistance to those with impairments. One area in particular where these devices can make an impact is the study and treatment of scoliosis. First, I adapt a design of a robotic torso exoskeleton to serve the population most susceptible to scoliosis, female adolescents. I used the device to compare the torso stiffness of members of this group with and without scoliosis, and found an interaction effect of degree of freedom (DOF) and torso segment on translational stiffness, and an interaction effect of DOF and group on rotational stiffness. These results can inform the models used to create rigid orthoses for conservative treatment or to simulate the effects of surgical procedures. Second, I explore the effects of different types of augmented sensory feedback commonly used in scoliosis physical therapy. I compare visual and force feedback provided by the exoskeleton on one’s ability to replicate static poses and dynamic movements. I find that while force feedback leads to faster initial improvement, visual feedback may enable the user to learn finer details of the movement. Third, I design a torso exoskeleton for people with neuromotor impairments. People who are not able to sit up independently are at a high risk of developing neuromuscular scoliosis, and must balance the benefits of treatment with rigid orthoses, with the limits that these devices place on functional movements. The device allows users four degrees of freedom, to support functional movements such as reaching and pressure relief maneuvers, but prevents lateral translation and axial rotation, which can contribute to neuromuscular scoliosis. Together, these results demonstrate the potential for robotic exoskeletons in torso study, training, and assistance.

Thesis (MScPhysio)--Stellenbosch University, 2012 / ENGLISH ABSTRACT: SYSTEMATIC REVIEW ABSTRACT - BACKGROUND: Ankle Foot Orthoses (AFOs) are considered as the most suitable lower limb orthosis to correct gait deficits related to ankle instability. AFOs are recommended to minimize gait deviations and to correct drop foot or equinus foot in hemiplegic patients. OBJECTIVES - To identify the effectiveness of different ankle orthoses and/or supports on the temporal, spatial, kinetic and kinematic gait parameters. To critically appraise the methodological quality of the included studies and to provide a description of the studies with a view to identify opportunities to improve future research quality. METHODS - Search strategy A comprehensive search was conducted between March and October 2010, and updated in August 2011. Thirteen computerized bibliographic databases were individually searched, namely PubMed Central, Cohrane Library, CINAHL, OT Seeker, SPORTDiscus, PsyARTICLE, PEDro, Proquest, Biomed Central, Science Direct, Clinicaltrials.gov, Web of Science, and Ingenta Connect. All databases were searched since their inception. The following key terms were used: stroke, hemipleg*, assistive device*, ankle foot orthos*, AFO, (splint*), taping, and strapping. A secondary search (pearling) was conducted by screening the reference lists of all eligible full text studies. The authors of the unpublished studies were conducted to minimize publication bias. Selection criteria The following selection criteria applied: all relevant randomized and non-randomized controlled trails published in English; participants were post-stroke patients older than eighteen years; interventions included any type of ankle foot orthosis (AFO), ankle taping or strapping and ankle foot splint without any additional intervention and the comparison/control groups were limited to walking without support, either barefoot or walking with shoes only. Studies were excluded when the outcome measures did not focus on at least one of the following: temporal spatial gait parameters, kinetic gait parameters or kinematic gait parameters. Data collection and analysis Two reviewers independently selected trials for inclusion and assessed methodological quality. The data was extracted by the primary reviewer and validated by a second reviewer. In event of disagreement, a third reviewer was asked to re-evaluate until consensus could be reached. Homogenous data were statistically summarized in sub-group meta-analysis using Revman© Review Manager Software. The results of heterogeneous data were summarized in a narrative form. MAIN RESULTS - The search yielded 11134 initial hits. Sixteen studies met the inclusion/exclusion criteria. The studies investigated the immediate effect of various types of AFOs on a broad range of temporal spatial gait parameters mainly gait speed, cadence, stride and step length. Only two studies reported on the kinetic and six on various kinematic gait parameters. The meta-analysis yielded significant improvement in gait speed (0.06 m/s; 95% CI 0.04, 0.08. p < 00001), walking cadence (5.41; 95% CI 3.79, 7.03. p < 00001), stride length (6.67; 95% CI 3.29, 10.06. p < 00001) and step length (2.66; 95% CI 1.59, 3.72. p < 0.00001). CONCLUSION - AFOs are effective to improve mobility, gait speed, cadence, stride and step length for post-stroke patients and may have a positive impact on the daily function of post-stroke patients. . The long term benefit or adverse effects of AFOs are still inconclusive. The effectiveness of AFOs on the kinetic and the frontal- or transverse- plane joint kinematics is largely unresolved. There is insufficient evidence to either support or refute the effectiveness of taping/strapping and splinting of the ankle on hemiplegic gait. EXPERIMENTAL STUDY ABSTRACT - BACKGROUND: Temporal, spatial and affected ankle kinematic gait parameters of adults with hemiplegia are significantly different from the normal able-bodied population. Enabling hemiplegic patients to walk is a major goal of rehabilitation programs. Taping of the plegic ankle could be utilized by therapists as external support of the ankle to improve foot position and placement during gait rehabilitation. OBJECTIVE - The purpose of the study was to describe the immediate effect of neutral ankle taping on temporal spatial gait parameters and ankle joint kinematics of the affected ankle in ambulant adult hemiplegic patients. METHODS - A clinical trial using a crossover randomized testing order was conducted on a convenient sample of ten ambulant hemiplegic patients at the Physiotherapy and Motion Analysis Clinic, Faculty of Health Sciences, Stellenbosch University, Tygerberg, Cape Town, South Africa. The affected ankle joint was taped in a neutral talocrural dorsiflexion/ plantarflexion and neutral hindfoot inversion/ eversion position using rigid adhesive tape (5 cm). The gait parameters were analysed according to the Plug-In Gait Model using a motion analysis system (Vicon Nexus 1.1.7; Vicon Motion System Limited, Oxford, UK). The analyses were repeated six times for each testing condition and the average values were used for further analysis. The data were analyzed using Least Square Means tests and post hoc Fisher (Least Significant Difference) LSD multiple comparison tests to determine the significant differences at 95% confidence level. RESULTS - The main results of the study indicate that taping of the affected ankle joint in a neutral position does not significantly improve (p>0.5) temporal spatial gait parameters and ankle joint kinematics in ambulant adult hemiplegic patients. The following positive trends were however found and need to be further explored in larger homogeneous study samples: ankle taping of ambulant adult hemiplegic patients has limited benefits on selected temporal parameters as ankle taping could potentially improve cadence. Ankle taping could decrease plantarflexion of the plegic leg at initial contact. CONCLUSIONS - A systematic review revealed no conclusive evidence either to support or refute the beneficial effects of ankle taping on gait parameters of ambulant adult hemiplegic patients. Ankle taping of ambulant adult hemiplegic patients has potential clinical benefits on temporal, spatial and affected ankle kinematics, gait cadence and affected leg swing and stance duration.

M. Tech. Electrical Engineering. / The hypothesis states that a closed loop control system could be applied to a mechatronic system consisting of a mechanical device(s) to be fitted onto the user, and other relevant periphery mechanical devices, appropriately actuated to provide powered movement to assist the wheelchair-bound individual securely attain a standing position.The premise upon which the hypothesis was to be tested relates to the control system's ability to facilitate the upward movement proposed and its degree of stability when simulating the system, thus re-creating the anticipated functionality.

published_or_final_version / abstract / toc / Orthopaedics and Traumatology / Master / Master of Philosophy