A Motion Capturing and Energy Harvesting Hybridized Lower‐Limb System for Rehabilitation and Sports Applications

Abstract

Lower-limb motion monitoring is highly desired in various application scenarios ranging from rehabilitation to sports training. However, there still lacks a cost-effective, energy-saving, and computational complexity-reducing solution for this specific demand. Here, a motion capturing and energy harvesting hybridized lower-limb (MC-EH-HL) system with 3D printing is demonstrated. It enables low-frequency biomechanical energy harvesting with a sliding block-rail piezoelectric generator (S-PEG) and lower-limb motion sensing with a ratchet-based triboelectric nanogenerator (R-TENG). A unique S-PEG is proposed with particularly designed mechanical structures to convert lower-limb 3D motion into 1D linear sliding on the rail. On the one hand, high output power is achieved with the S-PEG working at a very low frequency, which realizes self-sustainable systems for wireless sensing under the Internet of Things framework. On the other hand, the R-TENG gives rise to digitalized triboelectric output, matching the rotation angles to the pulse numbers. Additional physical parameters can be estimated to enrich the sensory dimension. Accordingly, demonstrative rehabilitation, human-machine interfacing in virtual reality, and sports monitoring are presented. This developed hybridized system exhibits an economic and energy-efficient solution to support the need for lower-limb motion tracking in various scenarios, paving the way for self-sustainable multidimensional motion tracking systems in near future.

Recent Progress in the Energy Harvesting Technology—From Self-Powered Sensors to Self-Sustained IoT, and New Applications

“…Thus, the EHs have been reported broadly and applied in the wearable-related energy harvesting and sensing fields, as shown in Figure 2. Some typical devices include an exoskeleton based on bidirectional TENG sensors for multiple degrees of freedom human motion sensing (Figure 2a) [148], a smart glove with TENG sensors and piezoelectric haptic feedback for human-machine interface (Figure 2b) [149], a lower-limb system with both TENG and PENG for rehabilitation and biomechanical energy harvesting (Figure 2c) [150], an insole based on TENG for scavenging the unused energy in walking (Figure 2d) [151], a smart sock that can monitor the human motion status and distinguish user identity with the output of TENG (Figure 2e) [152], a self-powered watch with the energy captured by TENG and electromagnetic generator (EMG) from human motions (Figure 2f) [153], a multi-functional armband based on TENG with grid-patterned electrodes for wireless communication and vehicle manipulation (Figure 2g) [154], a self-powered air filter applied in the mask (Figure 2h) [155], and a self-powered mechanosensation communication system based on TENG utilizing the eye motions (Figure 2i) [156], a sweat-based hybrid textile devices with biochemical energy harvesting from sweat and energy storage (Figure 2j) [157], a wearable perovskite solar cell for scavenging infrared energy from light (Figure 2k) [158], and a hybridized thermo-triboelectric generator for utilizing both mechanical energy and thermal energy from body motions and body heat (Figure 2l) [159].…”

“…Copyright 2020 American Association for the Advancement of Science); (c) structures designed for lower limb (Reprinted with permission from ref. [150]. Copyright 2021 John Wiley & Sons); (d) devices applied in shoes and insole (Reprinted with permission from ref.…”

“…Recently, as shown in Figure 6c, Gao et al developed a motion capturing and energy harvesting hybridized lower-limb system for rehabilitation and sports applications [150]. That system consists of a sliding block-rail piezoelectric generator (S-PEG) and lower-limb motion sensing with a ratchet-based triboelectric nanogenerator (R-TENG).…”

Progress in the Triboelectric Human–Machine Interfaces (HMIs)-Moving from Smart Gloves to AI/Haptic Enabled HMI in the 5G/IoT Era

“…Additionally, some customized interaction commands also require a certain learning cost for the users. To realize a more intuitive HMI for parallel manipulation with enhanced degrees of freedom in the applications of advanced industrial automation or virtual reality interactions, the sensory information of the human pose is of great significance [194][195][196][197]. Zhu et al proposed a customized exoskeleton enabled by triboelectric bidirectional sensors for upper limbs' joint motion monitoring as depicted in Figure 3g [172].…”

Wearable Self‐Powered Electrochemical Devices for Continuous Health Management

“…For these reasons, the development of hybrid systems that includes several energy harvesting modules is postulating to be the solution for constant power supply through an efficient energy conversion. [176] Hence, weaknesses and strengths from certain energy-harvesting technologies can be overcome by a synergistic effect. [177] Besides, the specific application of the WeSPED demands certain energy generators.…”