Exoskeletons can be helpful to patients who suffer from muscular dysfunctions. Recent studies focus on exoskeletons which can perform complex human movements. Further analysis is needed in the area of unusual movements like obstacle clearance to design an assistive device which can deliver effective aid to the intended patients in need. It is necessary to understand the behavior of lower limb muscles when they are subjected to complex physical activity. This study is aimed to analyze the activity of muscles in the lower body during obstacle clearance. Two different levels of obstacle have been maintained, analyzed and compared with a normal gait. The muscle groups taken for the study are quadriceps, hamstrings and plantar flexors. The primary hypothesis is that the quadriceps, Hamstrings, and dorsi flexors tend to have higher muscle activation while performing a complex physical task like stepping over an obstacle with the heights of 20 cms and 36 cms than a normal walking gait. The muscles from those three mentioned groups contribute more to the obstacle clearance compare to that of normal gait. Further research is recommended to expand knowledge about muscle activation.

Powered exoskeletons can assist patients suffering from motor dysfunctions. Recent researches are focused on how to improve the communication system between patient and device. Further research is needed in order to design an EMG based robotic assistive device able to convey intended motions to the patient. The primary need is the understanding of how EMG patterns from different muscles contribute to motions. Studies on muscle synergy have shown how different muscles of lower limbs contribute to gait. This study is aimed to expand the analysis to motions other than gait by analysing ten muscles around the right knee joint. The chosen muscle were soleus, gastrocnemius medialis, gastrocnemius lateralis, peroneus longus, tibialis anterior, rectus femoris, vastus medialis, vastus lateralis, biceps femoris and semitendinosus. The main hypothesis is that specific movements are controlled by specific muscle synergies. Motion data and EMG data of eight healthy subjects have been compared in order to outline a coordination pattern specific to four different movements: gait, gait stop and balance, sit to stand and stand to sit. Through the analysis of EMG signals, three muscle synergies have been identified including muscles from the same group, i.e. four plantar flexors, three quadriceps and two hamstrings. It was possible to conclude that the four movements were controlled by the same muscle synergies with different coordination patterns. Further research is recommended to expand the knowledge about muscle synergies.

Full-body powered exoskeletons for industrial workers have the potential to reduce the incidence of work-related musculoskeletal disorders while increasing strength beyond human capabilities. However, operating current full-body powered exoskeletons imposes different loading, motion, and balance requirements on users compared to unaided task performance, potentially resulting in additional mental workload on the user which may reduce situation awareness (SA) and increase risk of collision with pedestrians, negating the health and safety benefits of exoskeletons. Exoskeletons could be equipped with visual aids to improve SA, like rearview cameras or radar displays. However, research on design and evaluation of such displays for exoskeleton users are absent in the literature. This empirical study compared several augmented reality (AR) head-up displays (HUDs) in providing SA to minimize pedestrian collisions while completing common warehouse tasks. Specifically, the study consisted of an experimental factor of display abstraction including four levels, from low to high abstraction: rearview camera, overhead radar, ring radar, and no visual aid (as control). The second factor was elevation angle that was analyzed with the overhead and ring radar displays at 15°, 45°, and 90°. A 1x4 repeated measures ANOVA on all four display abstraction levels at 90° revealed that every display condition performed better than the no visual aid condition, the Bonferroni post-hoc test revealed that overhead and ring radars (medium and high abstraction respectively) received higher usability ratings than the rearview camera (low abstraction). A 2x3 repeated measures ANOVA on the two radar displays at all three display angles found that the overhead radar yielded better transport time and situation awareness ratings than the ring radar. Further, the two-way ANOVA found that 45° angles yielded the best transport collision times. Thus, AR displays presents promise in augment SA to minimize collision risk to collision and injury in warehouse settings. / Master of Science / Exoskeletons can increase the strength capabilities of industrial workers while reducing the likelihood of injury from heavy lifting and materials handling. However, full-body powered exoskeletons are currently very unwieldy, demanding users to focus their attention on controlling the exoskeleton that may cause a loss awareness of their surroundings. This may increase the likelihood of collisions with pedestrians, presenting a significant safety concern that could negate the benefits of exoskeletons. Rearview cameras and radar displays of nearby pedestrians could improve situation awareness for the exoskeleton user; however, these methods are not well-tested in settings where exoskeletons would be used. This study compared a rearview camera, a conventional radar, and a ring-shaped radar at display angles of 15°, 45°, and 90° using an augmented reality headset and simulated warehouse task to determine the combination of display type and angle that would maximize situation awareness and minimize collisions with pedestrians. The study revealed that all displays performed better than no display support and the latest evidence from this study and the literature suggests that a conventional overhead radar at 45° performed best.

Exoskeletons are getting popular day by day due to their abilities in helping people. Exoskeletons can be used to help people gain motor senses through rehabilitation. It can also help healthy people to augment their abilities. These exoskeletons need to be strong yet light, so that the human body can support the exoskeleton, while the exoskeleton can support the activity that is being performed. This calls for under-actuated systems, which help in avoiding unnecessary mass due to additional actuators, while providing the same movement capabilities. This thesis describes in detail about two such under-actuated upper body exoskeletons which can be used for lifting loads. The design of such exoskeletons and novel control techniques for comfortable usage is discussed in detail. / Master of Science / Exoskeletons are assistive devices which can help people in several ways. An exoskeleton can help people who are affected with stroke by enabling them to walk through rehabilitation and physiotherapy. It can also help people to perform beyond their capacity in terms of physical activities. This could be to lift more load than possible, run faster than usual. This thesis describes the design and working two such exoskeletons which can be attached to the upper body. These exoskeletons can be used by people to lift loads which would require a lot of effort and muscle activity. The addition of these exoskeletons potentially reduce the muscle activity on the user and helps avoiding injuries in long term. Such exoskeletons have to be light weight so that they do not defeat the purpose of reducing muscle activity. This problem is solved by using under-actuated systems, because a significant mass of the exoskeleton is taken by the actuators such as the motors. Using under-actuated systems help in lowering the mass of the exoskeleton, while still being able to perform the same kinds of motion. This thesis also talks about how these exoskeletons can be controlled such that the load is being lifted with minimal efforts, and being aware of the loads it is lifting to provide the correct amount of torque, above or below which can lead to the motor shooting up or down causing muscular discomfort and injuries in the arm.

<p>  </p> <p>To regain a healthy degree of hand function, injured patients require strenuous rehabilitation therapies with the expectation of gaining the full range of motion and strength necessary for performing activities of daily living (ADLs). Metacarpal fractures are one of the most common musculoskeletal injuries and require occupational therapy after the immobilization phase. Obstacles, such as longer recovery times, high costs, or lack of trained physiotherapists, often present a barrier for individuals seeking adequate treatment. Repetitive extension and flexion therapy routines improve grasping functionalities when performed correctly and repetitively. Robotic devices, such as hand exoskeletons, have been found to make up for the lack of hand motor function and assist in grasping tasks performed in ADLs, improving users’ independence. To increase robot acceptability, wearable robots have been recently proposed as part of rehabilitation technologies. Hand rehabilitation systems are an active research interest; however, most studies focus on rehabilitating central nerve injuries. There is a lack of research on systems treating hand fracture injuries, explicitly focusing on function recovery involving the fingers. Integrating systems that provide the necessary dexterity in a user-friendly manner while keeping a compact and lightweight fashion remains challenging. This thesis describes the development of a Soft Hand Exoskeleton (SHE) for robotic hand rehabilitation. The system integrates a flexible glove-like body and a bio-inspired cable-driven transmission system for motion assistance. The exoskeleton’s usage effects were evaluated through a user study experiment. An electromyography (EMG) based analysis allowed us to assess the muscular effort demands of ADLs. Experimental results and evaluation metrics demonstrated a reduction in the total integrated muscular activity (TIMA) in the performance of common ADLs when wearing the SHE system. </p>

Lifting weights, moving large, heavy objects, or maintaining same posture for extended periods of time exposes workers, mostly in the industrial sector, to pressure on their lower backs, which can have a significant negative impact and result in a variety of musculoskeletal problems and discomfort. The use of an exoskeleton can help to protect workers against lower back injuries of this kind. Past studies have been conducted to study the impact of the exoskeleton on upper body and legs with different exoskeleton, while this study will be an additional study which covers the impact on the most essential and used part of human body i.e., lower back (Thoracolumbar fascia). Workers working in the industrial sectors face more health issues and disabilities because of working on uneven surfaces, under uncomfortable positions like bending, squatting, twisting, and stretching which might impose adverse impact on lower back resulting in a higher number of sick leave.  If more people are impacted by disorders caused by lower back pain, the lesser would be the healthy workers available for work leading to shortage of competent workers in the industry. Back discomfort can affect a person's capacity to work; in fact, it's one of the most prevalent causes of temporary or permanent exclusion from the labor force when it comes to sick leave. The total estimated societal costs of low back pain in Sweden in 2001 was €1860 million, which included all medical expenditures as well as lost productivity as a result of the ailment. Estimates place the total economic cost of LBP in Sweden at €740 million, or €78 per person, for all episodes that started in 2011. [1].  This research study used a passive exoskeleton, namely “BackX”, developed by SUITX Inc. and its impact was measured on the body’s lower back in deep squatting and virtual chair position. Electromyography (EMG) sensors were deployed onto the participant's body as a measuring gadget. The investigations also examined the body muscle data of the various volunteers as recorded by the EMG sensors embedded in the thoracic-lumber fascia, a muscle in the lower back with and without exoskeleton.  The 3DSSPP model has also been used in this research to study the impact of force vs angle relation. It showed how much force was exerted on the human's lower back when lifting weights without wearing the exoskeleton.  In addition, using the proper data processing techniques, the signals from the acquired data will be filtered and processed. According to this study, it is possible to minimize skeletal muscle (Thoracolumbar fascia) activity by up to 60% by using these exoskeletons, which will improve the working conditions for the workforce by easing physical strain. The findings of this study will help small and medium enterprises (SMEs) spread the word regarding the advantages of exoskeletons, which will help to increase public awareness.

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This thesis details several modifications to the mechanical design of the Orthotic Lower Limb Exoskeleton (OLL-E) that improve upon the functionality and manufacturability of parts and their assemblies. The changes made to these parts maintain or improve the factor of safety against yield and fatigue failure as compared to the original designs. Design changes are verified by FEA simulations and hand calculations. The changes included in this thesis also allowed parts that were previously difficult or impossible to manufacture using traditional methods to be made in house or outsourced to another machine shop. In addition to the mechanical design changes, this thesis also details the design and implementation of a six axis force-torque sensor built into the foot of OLL-E. The purpose of this sensor is to provide feedback to the central control system and allow OLL-E to be self-balancing. This foot sensor design is calibrated and initial results are discussed and shown to be favorable. / Master of Science / Recent developments in the fields of robotics and exoskeleton design have increased their feasibility for use in medical rehabilitation and mobility enhancement for persons with limited mobility. The Orthotic Lower Limb Exoskeleton (OLL-E) is an exoskeleton specifically designed for enhancing mobility by allowing users with lower limb disabilities such as spinal cord injuries or paraplegia to walk. The research detailed in this thesis explains the design and manufacturing processes used to make OLL-E as well as providing design details for a force sensor built into the exoskeleton foot. Before manufacturing could take place some parts needed to be redesigned and this thesis provides insight into the reasons for these changes. After the manufacturing and design process was completed the OLL-E was assembled and the project can now move forward with physical testing.

Since the 1960s, research into the medical applications of wearable robots has been fueled by a growing need for assistive technologies that can help individuals impacted by musculoskeletal disorders such as sarcopenia independently manage common activities of daily living while maintaining their natural physical capacities. While contemporary research has demonstrated promising developments, the usefulness of exoskeletons in everyday settings remains limited due to design factors that include the limited practicality of existing battery technologies, the need for actuators exhibiting a high output torque-to-weight ratio, a need for modular designs that are minimally disruptive to wearers, and the need for control systems that can actively work in sync with a user. To explore potential solutions to some of these limiting factors, a novel ankle exoskeleton prototype supporting ankle plantarflexion during gait was developed under a design approach that seeks to optimize actuator performance. The actuation system featured in this prototype consists of a custom dual-action linear actuator that can provide mechanical assistance to both ankles via a single BLDC motor and an underlying Bowden cable system. The metric ball screw and BLDC motor implemented in the linear actuator were selectively chosen to minimize the motor torque and current required to assist wearers impacted by a degree of muscle weakness under an assistance-as-needed design paradigm. The prototype additionally features an array of force sensing resistors for tracking gait progression and exploring potential user-based control strategies for synchronizing the exoskeleton actuator with a wearer's gait. Performance analysis for this prototype was conducted with the goal of quantifying the exoskeleton's force output, actuator settling time, and the control system's ability to track gait and identify key events in the gait cycle. The preliminary findings of this experimental analysis support the viability of the actuator's dual-action concept and gait progression tracking system as a starting ground for future developments that build on a similar design optimization approach. / Master of Science / Healthy aging and good physical health are characterized in part by one's ability to self-manage a core set of daily living tasks, one of the most prominent of which is gait. Relative to existing assistive technologies such as wheelchairs, exoskeletons provide the unique benefit of providing active mechanical support while encouraging users to rely on their natural physical capabilities. While recent technological developments in the field of wearable robots show promise, the viability of exoskeletons in an everyday setting remains constrained in part by three underlying design factors: the limited practicality of existing battery technologies, a need for actuators that can satisfactorily balance a high force output with weight, and a need for control strategies that can properly synchronize wearable robots with users. The ankle exoskeleton prototype introduced in this thesis is a portable, energetically autonomous wearable device that supports ankle plantarflexion during the push-off stages of the gait cycle. The design for this prototype seeks to optimize actuator performance and features a novel dual-action linear actuator that provides walking support to both ankles using a single DC motor. The exoskeleton additionally features an array of contact sensors that track the user's progression throughout the gait cycle and allow for the examination of potential control strategies for synchronizing the actuator with the wearer's gait. Performance analysis conducted for this prototype quantifies the exoskeleton's force output, approximates the actuator's settling time between steps, and assesses the control system's ability to track gait and synchronize with a wearer. The findings from these performance evaluation experiments support the viability of the actuator's dual-action concept and gait progression tracker as a foundation for future developments that build on a similar design optimization approach.