Objective: To gather knowledge related to patient satisfaction and mobility with lower limb prosthetic and orthotic devices and to investigate satisfaction with services received. Another purpose of this study is to analyze potential differences between orthotic and prosthetic patients in relation to patient satisfaction and mobility. Design: Cross-sectional study Subjects: 21 participants with a mean age of 58 (SD 16) with an average duration of use of devices of 10 (SD 10) years. 12 out of the 21 participants were orthotic users and 9 were prosthetic users. Methods: Patients were asked to complete two questionnaires, one regarding satisfaction with assistive device and service (QUEST 2.0) and one regarding mobility. Results: Patients mean score regarding satisfaction with assistive device and service were 4.0 (SD 0.8) and 4.2 (SD 1.0) respectively. 91% reported that they had the ability to walk at least 100 meters with their assistive device. The areas where participants experienced most difficulties were walking on uneven ground (70%), walking up and down a hill (57%) and walking on stairs (57%). Conclusion: Overall this study demonstrates that participants were quite satisfied with their assistive device and the service received by the P&O clinic. No statistically significant differences regarding satisfaction with assistive device and service, or mobility, were found between prosthetic and orthotic participants.

This thesis presents the development and experimental testing of a lower-limb exoskeleton system. The device supplies assistive torque at the knee joint to alleviate the loading at the knee, and thus reduce the muscular effort required to perform activities of daily living. The hypothesis is that the added torque would facilitate the execution of these movements by people who previously had limited mobility. Only four specific movements were studied: level-waking, gradient-walking, sit-to-stand-to-sit and ascending stairs. All three major components of the exoskeleton system, i.e. the exoskeleton actuators and actuator control system, the user intention estimation algorithm, and the mechanical construction of the exoskeleton, were investigated in this work. A leg brace was fabricated in accordance with the biomechanics of the human lower-limb. A single rotational degree of freedom at the knee and ankle joints was placed to ensure that the exoskeleton had a high kinematic compliance with the human leg. The position of the pneumatic actuators and sensors were also determined after significant deliberation. The construction of the device allowed the real-world testing of the actuator control algorithm and the user intention estimation algorithms. Pneumatic artificial muscle actuators, that have high power to weight ratio, were utilized on the exoskeleton. An adaptive fuzzy control algorithm was developed to compensate for the inherent nonlinearities in the pneumatic actuators. Experimental results confirmed the effectiveness of the adaptive controller. The user intention estimation algorithm is responsible for interpreting the user's intended movements by estimating the magnitude of the torque exerted at the knee joint. To accomplish this, the algorithm utilizes biological signals that emanate from the knee extensor and flexor muscles when they are activated. These signals combined with the knee angle data are used as inputs to the estimation algorithm. The output is the magnitude and direction of the estimated torque. This value is then scaled by an assistance ratio, which determines the intensity of the assistive torque provided to the user. The experiments conducted verify the robustness and predictability of the proposed algorithms. Finally, experimental results from the four activities of daily living, affirm that the desired movements could be performed successfully in cooperation with the exoskeleton. Furthermore, muscle activity recorded during the movements show a reduction in effort when assisted by the exoskeleton.

As farmers continue to get older, they will likely face age-related disabilities that impede their ability to work and increase risk of suffering serious injuries. One of the major age- related diseases is arthritis, which currently accounts for about 40% of disability cases in agriculture nationwide. The effect of arthritis on farmers is profound because it reduces their physical strength, joint range of motion and is a source of joint pain, all culminating in the lack of ability to perform routine activities regularly and safely. One way to decrease the rate of injuries is by reducing the strength and joint loading required to perform these activities through the use of wearable robotics. As opposed to existing solutions that focus only on injury prevention, this thesis will present an active, knee-assist exoskeleton intent on providing 30% of the necessary joint rotation force to perform activities such as sit-to- stand actions and the ascent/descent of stairs and hills. The device will be a lightweight, unobtrusive cable-driven exoskeleton actuated by distally-worn electric motors. We hope that use of the exoskeleton will result in increased ranges of motion and overall reduction of stress on the wearer's body, which will minimize the effects of arthritis and ultimately improve safety and quality of life. / Master of Science / As farmers continue to get older, they will likely face age-related disabilities that impede their ability to work and increase risk of suffering serious injuries. One of the major age-related diseases is arthritis, which currently accounts for about 40% of disability cases in agriculture nationwide. The effect of arthritis on farmers is profound because it reduces their physical strength, joint range of motion and is a source of joint pain, all culminating in the lack of ability to perform routine activities regularly and safely. One way to decrease the rate of injuries is by reducing the strength and joint loading required to perform these activities through the use of wearable robotics. As opposed to existing solutions that focus only on injury prevention, this thesis will present an active, knee-assist exoskeleton intent on providing 30% of the necessary joint rotation force to perform activities such as sit-to-stand actions and the ascent/descent of stairs and hills. The device will be a lightweight, unobtrusive cable-driven exoskeleton actuated by distally-worn electric motors. We hope that use of the exoskeleton will result in increased ranges of motion and overall reduction of stress on the wearer’s body, which will minimize the effects of arthritis and ultimately improve safety and quality of life.

Individuals with upper limb motor deficits due to neurological conditions, such as stroke and traumatic brain injury, may exhibit hypertonia and spasticity, which makes it difficult for these individuals to open their hand. The Hand Orthosis with Powered Extension (HOPE) Hand was created in 2018. The performance of the HOPE Hand was evaluated by conducting a Box and Blocks test with an impaired subject. Improvements were identified and the HOPE Hand was mechanically redesigned to increase the functionality in performing grasps. The original motor configuration was reorganized to include active thumb flexion and extension, as well as thumb abduction/adduction. An Electromyography (EMG) study was conducted on 19 individuals (10 healthy, 9 impaired) to evaluate the viability of EMG device control for the specified user group. EMG control, voice control, and manual control were implemented with the HOPE Hand 2.0 and the exoskeleton system was tested for usability during a second Box and Blocks test.

Quadriceps muscle weakness is a condition that can result from a wide variety of causes, from diseases like polio and multiple sclerosis to injuries of the head and spine. Individuals with weakened quadriceps often have difficulty supplying the knee-extension moments required during common mobility tasks. Existing powered orthoses that provide an assistive knee-extension moment are large and heavy, with power supplies that generally last less than two hours. A new device that provides a knee-extension-assist moment was designed to aid an individual with quadriceps muscle weakness to stand up from a seated position, sit from a standing position, and walk up and down an inclined surface. The knee-extension-assist (KEA) was designed as a modular component to be incorporated into existing knee-ankle-foot-orthoses (KAFO). The KEA consists of three springs that are compressed, as the knee is flexed under bodyweight, by cables that wrap around a sheave at the knee. The KEA returns the stored energy from knee flexion as an extension moment during knee extension. During swing or other non-weight bearing activities, the device is disengaged from the KAFO by decoupling the sheave from the KAFO knee joint, allowing free knee joint motion. A prototype was built and mechanically tested to determine KEA behaviour during loading and extension and to ensure proper KEA function. For biomechanical evaluation, able-bodied subjects used the prototype KEA while performing sit-to-stand, stand-to-sit, ramp ascent, and ramp descent tasks. The KEA facilitated sitting and standing, providing an average of 53 % of the required extension moment for the two participants, which allowed one participant to reduce quadriceps usage by 38 % and the other to perform sit-to-stand in a slower and more controlled manner that was not possible without the KEA. KEA use during ramp gait caused an overall increase in quadriceps activation by 76 %, on average, with use. Future efforts will be made to modify the design to improve functionality, especially for ramp gait, and to reduce device size and weight.

Grab-bars and transfer poles are common sit-to-stand aids for older adults with mobility limitations. This study investigates differences in kinematics and kinetics in the lower limbs across different transfer pole configurations and positions. Configurations tested are a single pole, two poles and a pole with a horizontal grab-bar at near and far positions. Three-dimensional biomechanics were used to calculate kinetics and kinematics of the lower extremities. Forces were also recorded from the pole. This study found horizontal pole forces were an effective replacement for trunk generated horizontal momentum. Reduced vertical pole forces were applied by participants using the `far' poles which resulted in increases in non-dominant hip moments when using the single and double pole configurations. Horizontal pole use introduced non-dominant directed lateral COM trajectory throughout the movement. This coincided with increased horizontal forces in the dominant foot to balance moments about COM in the transverse plane as a motor control strategy.

Grab-bars and transfer poles are common sit-to-stand aids for older adults with mobility limitations. This study investigates differences in kinematics and kinetics in the lower limbs across different transfer pole configurations and positions. Configurations tested are a single pole, two poles and a pole with a horizontal grab-bar at near and far positions. Three-dimensional biomechanics were used to calculate kinetics and kinematics of the lower extremities. Forces were also recorded from the pole. This study found horizontal pole forces were an effective replacement for trunk generated horizontal momentum. Reduced vertical pole forces were applied by participants using the `far' poles which resulted in increases in non-dominant hip moments when using the single and double pole configurations. Horizontal pole use introduced non-dominant directed lateral COM trajectory throughout the movement. This coincided with increased horizontal forces in the dominant foot to balance moments about COM in the transverse plane as a motor control strategy.

Quadriceps muscle weakness is a condition that can result from a wide variety of causes, from diseases like polio and multiple sclerosis to injuries of the head and spine. Individuals with weakened quadriceps often have difficulty supplying the knee-extension moments required during common mobility tasks. Existing powered orthoses that provide an assistive knee-extension moment are large and heavy, with power supplies that generally last less than two hours. A new device that provides a knee-extension-assist moment was designed to aid an individual with quadriceps muscle weakness to stand up from a seated position, sit from a standing position, and walk up and down an inclined surface. The knee-extension-assist (KEA) was designed as a modular component to be incorporated into existing knee-ankle-foot-orthoses (KAFO). The KEA consists of three springs that are compressed, as the knee is flexed under bodyweight, by cables that wrap around a sheave at the knee. The KEA returns the stored energy from knee flexion as an extension moment during knee extension. During swing or other non-weight bearing activities, the device is disengaged from the KAFO by decoupling the sheave from the KAFO knee joint, allowing free knee joint motion. A prototype was built and mechanically tested to determine KEA behaviour during loading and extension and to ensure proper KEA function. For biomechanical evaluation, able-bodied subjects used the prototype KEA while performing sit-to-stand, stand-to-sit, ramp ascent, and ramp descent tasks. The KEA facilitated sitting and standing, providing an average of 53 % of the required extension moment for the two participants, which allowed one participant to reduce quadriceps usage by 38 % and the other to perform sit-to-stand in a slower and more controlled manner that was not possible without the KEA. KEA use during ramp gait caused an overall increase in quadriceps activation by 76 %, on average, with use. Future efforts will be made to modify the design to improve functionality, especially for ramp gait, and to reduce device size and weight.

Assistive technologies traditionally rely on either strong actuation or passive structures to provide users with increased strength, support or the ability to perform lost functions. At one end of the spectrum are powered exoskeletons, which significantly increase a user’s strength, but require strong actuators, complex control systems, and heavy power sources. At the other end are orthoses, which are generally unpowered and lightweight devices that rely on their structure’s mechanical behaviour to enhance user’s support and stability. Ideally, assistive technologies should achieve both systems’ characteristics by enhancing human motion abilities while remaining lightweight and efficient. This can be achieved by using distinctive actuators to harness gait energy, towards enhancing human mobility and performance. Pneumatic Artificial Muscles (PAMs), compliant and flexible, yet powerful and lightweight, present a unique set of characteristics compared to other mechanical actuators in human mobility applications. However, given the need of a compressor and power source, PAMs present a significant challenge, limiting their application. In contrast, PAMs can be implemented as unpowered actuators that act as non-linear elastic elements. This thesis aims to develop a wearable lightweight unpowered ankle exoskeleton, which relies on the PAM to harness gait energy and compliment the human ankle biomechanical abilities at the push off movement, thusly assisting the user in propelling the body forward during walking. Presently, limited PAM models have been developed to analyse PAM passive behaviour and to assist in designing and selecting the appropriate PAM for unpowered application. Thus, this thesis aims to develop a passive model for the PAM. To mechanically validate the proposed exoskeleton design, a prototype is fabricated, and tested within an Instron tensile machine setup. The unpowered exoskeleton has shown its ability to provide significant contribution to the ankle timed precisely to release at the push off phase of the gait cycle. Furthermore, the proposed PAM stiffness model is validated experimentally, and accounts for muscle pressure, geometry, material and stretching velocity. This enables the evaluation of the impact of various parameters on the muscle behaviour and designs the PAM accordingly for the unpowered ankle exoskeleton

Wheelchair-bound individuals who have limited or no upper-limb usage have difficulty with picking and placing of objects, opening doors, and other activities of daily living (ADLs), such as turning on a light switch or drinking from a cup. A wheelchair-mounted robot arm (WMRA) would aid individuals with completing ADLs and increase their independence, therefore an improved WMRA has been designed. Building upon previous WMRA research and incorporating research from industrial robot arms, carbon fiber tubing is the main component for the structure of the arm, a novel development for WMRAs. Factors that go into WMRA design include weight, speed, safety, robustness, cost, and the anticipated tasks. Many of these factors, such as weight, speed, and cost, can be improved upon compared to previous WMRAs by using carbon fiber materials. The use of carbon fiber enables the arm to be strong, but also lighter weight than other WMRAs. Testing was conducted on the pultruded carbon fiber tubing to ensure that the structure of the arm could withstand the necessary bending and tensile forces for the arm to hold up to 3.85kg, the standard weight of a gallon of milk, at the end effector. The arm's carbon fiber frame also allows the motor and sensor wiring to run internally, which improves the arm's safety and aesthetics, while protecting it from the arm's external environment. Lightweight high-torque motors, harmonic drives, newly designed carbon fiber frame, and a stand-alone 8-axis motion-control board, allow the arm to weigh less, have a longer overall length, be more robust, and be safer electronically than the previous University of South Florida WMRA, which was shown through prototype testing.