Design of a Wearable Device for Real-Time Gait Correction

Gait Analysis is the quantitative study of the motion of the human body during the gait. The attractive feature of gait analysis regards the possibility to study and to quantify the effects on the human motor functions caused by pathologies and lesions relative to the neuromuscular control system and to the musculoskeletal system Nowadays, the gold standard for the functional evaluation of the human gait is the gait analysis laboratory. With the development of wearable technologies, the applications of portable devices for gait analysis applications have become more and more popular. In these years, many authors have proposed valuable devices for wearable gait analysis applications achieving optimum results. The advantage of these solutions is that they can provide real-time sensory feedbacks to the patients thanks to the possibility of embedding small actuators, such as buzzers or vibrating motors. Therefore, the wearable devices can also perform re-training of the patients in order to normalize abnormal walking patterns. In-toeing is a condition in which the foot points internally during the gait instead of being parallel to the walking direction. The three main causes that determines this particular disease are: femoral anteversion, metatarsus adductus, and internal tibial torsion. This condition is very popular in children and it tends to vanish with the growth of the child. However, if it is not properly assessed, in-toeing can persist also in the adult stage. The main existing solutions can be either non-surgical (gate plates, orthodic devices, …) or surgical (tibial osteotomy) and their effectiveness is still debated in the literature. The aim of the project is to develop a wearable device in order to provide a different alternative solution. Many authors demonstrated that the Foot Progression Angle influences plantar pressure distribution. In-toeing causes a shift of the load toward the lateral part of the foot while out-toeing, on the other end, causes higher medial pressures. The idea at the base of the development of the device is to renew and redesign a project developed by the authors that consisted in the development of a smart insole for the real-time gait correction. The insole measured the relative difference of the plantar pressure between the different areas of the foot with force sensing resistors. These signals were collected and processed by a microcontroller that, according to the input information, controls the activation of a haptic feedback unit. The focus of the activity is to overcome the limitations and constrains of the original prototype. We changed the structure of the device from an insole to a sock. We chose this solution in order to can take advantages of sewing technologies in order to be able to embed the hardware in the fibers of the socks and to obtain a more compact device. The development of the project started from the strengths of the previous work: plantar pressure processing, real-time gait evaluation, haptic feedback actuation, and wireless communication. The new components and features that we introduced include: three axis gyroscope, coin battery, angular rate processing, sensors fusion for improving the temporal accuracy of stance identification, separated slave-unit for haptic feedback actuation and a development of a mobile application to extend the usability of the GUI. The proposed device can potentially constitute a valuable future solution in the correction of in- and out-toeing. The design and the development of the device started at the University of Illinois at Chicago where the idea of the project was created. The final realization of the devices has been achieved with the cooperation of TBM Lab of Politecnico di Milano.