A Lightweight Exoskeleton-Based Portable Gait Data Collection System

Abstract

For the controller of wearable lower-limb assistive devices, quantitative understanding of human locomotion serves as the basis for human motion intent recognition and joint-level motion control. Traditionally, the required gait data are obtained in gait research laboratories, utilizing marker-based optical motion capture systems. Despite the high accuracy of measurement, marker-based systems are largely limited to laboratory environments, making it nearly impossible to collect the desired gait data in real-world daily-living scenarios. To address this problem, the authors propose a novel exoskeleton-based gait data collection system, which provides the capability of conducting independent measurement of lower limb movement without the need for stationary instrumentation. The basis of the system is a lightweight exoskeleton with articulated knee and ankle joints. To minimize the interference to a wearer’s natural lower-limb movement, a unique two-degrees-of-freedom joint design is incorporated, integrating a primary degree of freedom for joint motion measurement with a passive degree of freedom to allow natural joint movement and improve the comfort of use. In addition to the joint-embedded goniometers, the exoskeleton also features multiple positions for the mounting of inertia measurement units (IMUs) as well as foot-plate-embedded force sensing resistors to measure the foot plantar pressure. All sensor signals are routed to a microcontroller for data logging and storage. To validate the exoskeleton-provided joint angle measurement, a comparison study on three healthy participants was conducted, which involves locomotion experiments in various modes, including overground walking, treadmill walking, and sit-to-stand and stand-to-sit transitions. Joint angle trajectories measured with an eight-camera motion capture system served as the benchmark for comparison. Experimental results indicate that the exoskeleton-measured joint angle trajectories closely match those obtained through the optical motion capture system in all modes of locomotion (correlation coefficients of 0.97 and 0.96 for knee and ankle measurements, respectively), clearly demonstrating the accuracy and reliability of the proposed gait measurement system.

New Directions in Sensor Research: A Bibliometric Analysis for Detecting Emerging Research Fields and New Technological Trajectories

“…This study confirms that flexible, stretching, and soft technologies are growing to enable wearable devices to be more usable in daily life activities (Zhao et al, 2020). Such technologies and human motion sensing analysis studies are rising because of the importance of disabled people's living conditions enhancement, (Čuljak et al, 2020;Haque et al, 2021). In this context, results here suggest that future developments are directed to improve material flexibility, softness, and comfort of the wearable technologies (e.g., artificial legs and hands devices) to be used properly in patients (Chheng and Wilson, 2021).…”

Scientific Developments and New Technological Trajectories in Sensor Research

“…This study confirms that flexible, stretching, and soft technologies are growing to enable wearable devices to be more usable in daily life activities [ 97 ]. Such technologies and human motion sensing analysis studies are rising because of the importance of disabled people’s living conditions enhancement [ 98 , 99 ]. In this context, results here suggest that future developments are directed to improve material flexibility, softness and comfort of the wearable technologies (e.g., in artificial legs and hands devices) to be used properly in many patients [ 100 ].…”

Exoskeleton-Based Multimodal Action and Movement Recognition: Identifying and Developing the Optimal Boosted Learning Approach

“…Usually, the specific structure of a lower leg exoskeleton contains three sections or components -the thigh section, the shank section, and the foot section. Specialized joints link these sections, which can detect and quantify the motions of the user's biological joints [40][41][42]. To encompass the range of motion for the knee and ankle about both the frontal and sagittal planes, a degree of freedom is often added.…”

“…To encompass the range of motion for the knee and ankle about both the frontal and sagittal planes, a degree of freedom is often added. This additional degree of freedom allows unrestricted movements in the frontal plane without interfering with the measurement of the joint sensors [42]. This range of features and capabilities of lower limb exoskeletons serves as our motivation for discussing how our framework can be integrated into the same.…”