## 1 Introduction
[12] conducted an in-depth exploration of the fundamental properties, theoretical underpinnings, manufacturing techniques, and applications of piezoelectric materials. Their focus extended to the flexibility and stretchability of inorganic, polymeric, and biological piezoelectric materials, elucidating recent advancements in piezoelectrics, piezophotonics, object structures, and self-powering technologies. Recognizing the necessity for piezoelectric materials to seamlessly convert mechanical and electrical energy, [PERSON] and [PERSON]'s research [13] delves into the stacking method employed. Their study reveals that a PZT comprises multiple piezoelectric plates with very thin dielectric material serving as a separation between layers while electrodes are connected along the sides of the PZT. In the realm of energy utilization, [PERSON] and [PERSON] [14] propose the incorporation of a Power Management Circuit (PMC) to store and harness the converted electrical energy. Furthermore, [PERSON] and their collaborators have conducted experiments aimed at minimizing the size and weight of the power management system, facilitating its integration into small mechanical equipment. This study builds upon the findings of [PERSON] and [PERSON] [15] with significant enhancements. [PERSON] and [PERSON] [15] investigated a dual elastic steel sheet energy harvesting system, where a PZT is affixed to the free end of one elastic steel sheet, and a magnet is attached to the free end of another elastic steel sheet. Their approach involved simulating helicopter-generated downwash to induce deformation in an elastic beam with a magnet, causing it to rebound and slap a PZT on the free end of another elastic beam, thus generating electrical energy. However, the fixed-free system's limited deformation at the free end of the elastic steel sheet constrained it to rely solely on flapping for electricity generation, preventing efficient utilization of the deformation force. In a related vein, [PERSON] et al. [16] conducted research on a fixed-free beam system. Their designed mechanism mirrors that of [PERSON] and [PERSON] [15], constituting a dual elastic steel sheet energy harvesting system with components such as beams, magnets, PZTs, and rotating disks, forming a bi-stable VEH system. Liketheir predecessors, [PERSON] et al. [16] positioned a PZT at the free end of one elastic steel sheet and a magnet at the free end of another elastic steel sheet. They utilized the magnet on the rotating disk to drive the magnet on the elastic beam, inducing deformation in the elastic beam. Concurrently, they harnessed the energy from the deformed elastic beam to slap the elastic beam carrying the PZT, thus generating power. Nevertheless, akin to [PERSON] et al. [15], the PZT was primarily influenced by slapping forces, unable to fully undergo deformation due to the minimal deformation at the free end of the elastic beam. In contrast, the elastic steel sheet experienced more substantial deformation near its fixed end. To surmount this challenge, we devised a seesaw-like mechanism illustrated in Figure 1. The slap-type VEH system concept is shown in Figure 2. As shown in Figure 2, a rotating shaft equipped with magnets is employed to induce vibrations in the adjacent elastic steel sheet through magnetic repulsion, leading to its vibration. The resulting vibrations cause the adjacent seesaw-type rigid plate lever to oscillate, slapping the PZT installed at the root of the elastic sheet. Consequently, this design facilitates the conversion of vibrational energy into electrical energy. The unique feature of this design enables the PZT to withstand both deformation and flapping forces simultaneously, resulting in superior power conversion efficiency. Figure 1: Slap-type VEH system 3D mechanism diagram. Figure 2: Slap-type VEH system concept diagram. In this study, the wind force can be derived from the downstream flow field generated by rotorcraft, fixed-wing aircraft, motorcycles, bicycles (see Figure 3), and other moving objects.