Soft wearable flexible bioelectronics integrated with an ankle-foot exoskeleton for estimation of metabolic costs and physical effort

Abstract

Activities and physical effort have been commonly estimated using a metabolic rate through indirect calorimetry to capture breath information. The physical effort represents the work hardness used to optimize wearable robotic systems. Thus, personalization and rapid optimization of the effort are critical. Although respirometry is the gold standard for estimating metabolic costs, this method requires a heavy, bulky, and rigid system, limiting the system’s field deployability. Here, this paper reports a soft, flexible bioelectronic system that integrates a wearable ankle-foot exoskeleton, used to estimate metabolic costs and physical effort, demonstrating the potential for real-time wearable robot adjustments based on biofeedback. Data from a set of activities, including walking, running, and squatting with the biopatch and exoskeleton, determines the relationship between metabolic costs and heart rate variability root mean square of successive differences (HRV-RMSSD) (R = −0.758). Collectively, the exoskeleton-integrated wearable system shows potential to develop a field-deployable exoskeleton platform that can measure wireless real-time physiological signals.

Skin preparation–free, stretchable microneedle adhesive patches for reliable electrophysiological sensing and exoskeleton robot control

“…However, signal instability caused by subject movement and skin secretion poses challenges to the practical use of EMG-based assistive robot control ( 67 ). In addition, the cumbersome wired sensor system necessitates extensive setup time and restricts the user’s natural movement range, confining the exoskeleton robot’s application to laboratory settings ( 68 ).…”

“…The assistive torque is conveyed to the hip joint of the user through the closed-loop pneumatic controller, using the desired pneumatic pressure obtained from the actuator inverse model. This assistive strategy prevents musculoskeletal disorders by reducing muscle overexertion and fatigue resulting from repetitive lifting of heavy loads ( 68 , 69 ). Furthermore, an additional wireless SNAP system is attached to the back muscle, where the target muscle is located [L1 vertebral level of Longissimus thoracis (L1)].…”

Advances in Respiratory Monitoring: A Comprehensive Review of Wearable and Remote Technologies

“…The AS7058 (OSRAM, Munich, Germany) [106] features two 20-bit ADCs for PPG acquisition and one 20-bit ADC for ECG/BioZ acquisition, capable of measuring respiration. A good example of the application of these bioimpedance sensors is the soft flexible bioelectronic system by Kim et al [33], who applied it to calculate metabolic costs and physical effort.…”

Graphene/Carbon Nanotube Conductive Ink-Based Biomimetic Structure for Self-Powered Flexible Medical Monitoring Devices

“…Soft wearable sensing devices have attracted extensive research attention in the fields of e-skin, human health monitoring, and medical image-assisted diagnosis due to the advantages of integrated functions, high sensitivity response, and good biocompatibility. − However, the existing sensors are unable to achieve a highly sensitive response over a wide sensing range. , In addition, the sensors require external power supply during utilization. − These conditions hinder the further development of flexible wearable sensing devices. Soft wearable sensing devices having both highly sensitive response over a wide sensing range and self-powered sensing characteristics are the key issues requiring a solution at present.…”