Nonlinear Dynamic Performance of Low‐Frequency Vibration Energy Harvesting Systems Based on an Adjustable Rhombic Inertia Amplifier and Gear‐Adjustable Device

Harvesting energy from vibrations at different frequencies is a prominent research topic. This article proposes adjusting the effective stiffness of the system by modulating the rotation angle of gears, thereby enabling more efficient energy harvesting under varying vibration conditions. The gear assembly is connected to a large mass block, with two spring‐connected mass blocks attached to either side of the lower rhombic link. For the system incorporating gear adjustment and an inertia amplifier, equations of motion are derived. Subsequently, plots are generated for the root mean square value of induced voltage, bifurcation diagrams of displacement versus excitation amplitude at different initial angles of the inertia amplifier, and coexistence attractor diagrams. Phase trajectory variations under different initial conditions are also investigated. By adjusting the gear rotation angle, the distribution of chaotic regions and the effective range for energy harvesting are modified. Results demonstrate that this device facilitates efficient adaptation to varying vibration energy collection conditions. Modifying the initial angle of the inertia amplifier and the gear rotation angle significantly optimizes energy harvesting efficiency.