Sistema portable de sensores integrados para la adquisición de datos hacía el diseño de exoesqueletos stars

Abstract

Introduction Biomechanical research has led to the development of different types of exoskeletons in the last decade. Assistive exoskeletons allow patients with different levels of spinal cord injuries to walk with the assistance of crutches. However, aspects such as the retail price, maintenance cost, and the medical device demanding requirements (FDA and EU MDR), limit its use to research and hospitals (therapy-based). This proposes the need to increment the efficiency of the design process. Conventional motion-capture systems based on cameras and markers involve high investment for research labs and qualified staff, tranlating into the exoskeleton design costs. In addition, these systems present limitations in outdoor environments, due to its stationary equipment. Indicating the need to improve the cost efficiency and the versatility of Motion Capture Data Acquisition Systems. Methodology This research focuses on the design and development of a novel Wearable Sensor-Integrated System for Data Acquisition and online visualization tools that replace the need of conventional equipment. It has an evolutionary design that allows the exoskeleton structure to transform into an assistive lower limb exoskeleton in a second phase. It is based on a 3D printed lower body exoskeleton that measures the kinematics with integrated encoders at each joint in the sagittal plane, for the upper body motion, low cost IMUs where used. The ground reaction force is acquired through sensitive insoles. An online visualization software tool was developed to do motion analysis and a full body segment model was used, creating a system capable of obtaining the joint torques through inverse dynamics. Results The results showed trajectories of the kinematic data similar to those obtained in previous studies by conventional systems of cameras and markers. The ground reaction forces also follow similar trajectories to those obtained in previous research with the use of force plates. Kinematic and kinetic results obtained by the system showed similar accuracy and standard deviations to that of conventional systems based on cameras, markers and force plates. The developed correction methods for the vertical component of the ground reaction force, showed promising results in the use of sensitive insoles using 9, 12 and 14 sensors. The vertical ground reaction force results showed deviations lower than 0,1 for the normalized values of the total subject weight, using 9 sensor insoles. The results using Matlab-Simulink as a simulation environment, proved the application of the system as a base for the development of software simulation tools. Conclusions The Wearable Sensor-Integrated System for Data Acquisition Systems allows replacing the use of conventional motion capture systems, regardless of the environment of application. It provides a portable system for Data Acquisition in outdoor environments, at an affordable cost. The use of integrated sensors in the lower body exoskeleton offers a physical device for the design and simulation of exoskeletons. The system has an evolutionary design; therefore it can be easily evolved according to the researcher specifications. It provies a cost efficient tool for researchers involved in the design of lower body exoskeletons.