Self-weight utilization harvester oriented to low-frequency gait for human health monitoring and assistive training

Abstract

The mechanical energy generated during human daily activities holds the potential as a viable energy source for health monitoring and assistive devices. However, the vibrational energy generated from human walking is difficult to harvest due to the characteristics of low-frequency, especially considering the exemption of the additional walking burden. This work introduces an energy harvesting system incorporating an innovative spiral-spring and flywheel combination based on self-weight utilization strategy, alongside an excitation matching methodology to achieve efficient energy conversion. By utilizing a smart plucking structure with a piezoelectric cantilever beam to match the excitation displacement and force with the locomotion in the leg-stretching phase. The system can obtain a power output of 38.07mW, and 58.62mW at walking speeds of 1.0 m/s, and 3.0 m/s without imposing additional burden on the human by self-weight utilization strategy. Moreover, it can provide assistive force for gait movement due to the unique plucking structure realizing asymmetric loading style. The system showcases its potential as a lightweight, cost-effective, and ergonomic solution for the needs of adults requiring assistive training and health monitoring.