Theoretical Design and Experimental Study of a Piezoelectric Energy Harvesting System for Self-Powered Ski Boots

At present, energy harvesting technologies are gradually replacing batteries and have become a research hotspot as power sources for low-power components in wearable electronic devices. To collect and utilize the energy generated by skiers during the process of pushing against the skis, a piezoelectric energy harvesting system (PEHS) for self-powered ski boots was proposed and designed to supply power for low-power wearable devices. The output voltage of the PEHS was modeled and simulated using the finite element method, and the causes of the simulation results were analyzed. An energy harvesting experiment of the prototype was conducted under loading conditions using a universal testing machine. Under a uniform sinusoidal load of 800 N at 1 Hz, the prototype of the PEHS for self-powered ski boots achieved a maximum output power of 57.44 mW with an optimal matching load resistance of 404 kΩ. A skiing tester wearing the self-powered ski boots conducted real-motion experiments, performing three different actions: (1) alternating single-foot stepping for propulsion, (2) alternating left and right ski edge stepping for propulsion, and (3) alternating forefoot and heel stepping for propulsion. The instantaneous peak voltages measured in these tests were statistically analyzed, and the corresponding peak power values were calculated through theoretical computation to be 6.48 ± 0.27 mW, 4.47 ± 0.21 mW, and 13.21 ± 0.48 mW for the three actions, respectively (expressed with a 95% confidence interval).