Concurrent with the climbing rate of world life expectancy, the number of people with age related disabilities and impairments has increased placing unprecedented demands on global healthcare systems and aging-related services. Among the wide range of realms of possible disabilities, gait related impairment have been of great interest as walking is a fundamental function of one’s daily routine and a key component for the overall quality of life.
Passive ankle foot orthoses (AFOs) are generally customizable, lightweight, compact, and relatively inexpensive. As a result, passive AFOs make up the majority of the devices prescribed by clinicians to treat dysfunctions of the ankle joint. Despite the popularity, the inability to provide assistive torque during gait and inhibition of necessary ankle motion limits the functional benefit of passive AFOs. To address these limitations, current research efforts have been directed towards the development of active AFOs.
Recent advances in actuator and sensor technologies have contributed to the growth of active AFOs. Variable dampers and series elastic actuators have been developed to power AFOs and showed promising results in improving ankle functionality. The considerable masses of the systems still limit such devices in the practical perspective. To minimize counterproductive effects of the additional masses introduced by the system, remote actuation mechanisms can be utilized to distribute the masses closer to the trunk of the body.
Pneumatic powered systems carry great potential for remote actuation, especially in wearable robotic applications as pressurized air can be easily transferred through flexible tubing to remote locations. This allows flexibility in the placement of system components of the assistive device elsewhere on the body, resulting in light weight and compact sized AFOs. Moreover, the compressibility of air provides inherent compliance allowing safe and comfortable interaction between the AFO and user without additional mechanisms.
Despite the significant advantages of a pneumatic powered system, the large stationary air compressors required to supply pressurized air are large, bulky and tethered. Therefore, the objective of the work presented in this dissertation is to first design a portable air compressor that can be worn on the trunk of the body and can generate pressurized air that is sufficient to assist the dorsiflexion motion of the ankle. Along with the designed portable air compressor, a compact, lightweight, active ankle-foot orthosis was developed. Then as a proof-of concept, the developed system is tested on three drop foot patients with impaired dorsiflexor muscles. Improved ankle kinematics in the sagittal plane and pelvic tilt in the coronal plane was achieved. It is believed that this development has shown the potential that pneumatic energy sources can be miniaturized by optimizing the source with respect to the application. This can allow pneumatic systems to be fully portable, wearable and extended to other wearable applications.
본 논문의 최종 목표는 은닉형 능동 보행 보조기의 원천기술을 개발하고 이를 기술적, 임상적으로 검증하는것이다. 이상 보행은 사고, 고령화, 신경이상, 잘못된 습관 등 다양한 이유로 발생하며 이는 심각한 이차 근골격 장애를 초래하고 삶의 질 저하로 연결된다. 현재 개발되는 보행 보조를 위한 능동형 발목 관절 보조기(Ankle foot orthosis)는 두드러지게 큰 크기와 큰 소음이 발생하는 단점이 있으며 이는 낙인 효과(Stigma effect)로 인해 사용이 기피되고 있다. 이를 해결하기 위해 착용형(Wearable) 고용량 공압 압축기 기술과 착용부와 동력전달부가 드러나지 않으며, 저소음으로 착용을 감출수 있는 은닉형 능동 관절 보조기를 개발하였다.
