Synchronization of the vibration system driven by four eccentric rotors with perpendicular and coplanar axes

This paper proposes a vibration mechanical structure capable of achieving two synchronous motion states. Its distinctive feature lies in utilizing four eccentric rotors (ERs) with coplanar and perpendicular axes as the excitation source. By modeling this vibration system and conducting theoretical analysis, the synchronous condition and its stability for achieving synchronous motion among four ERs are obtained. Based on theoretical results, the dynamic characteristics, coupling torques, synchronous capability coefficients and phase differences of ERs are discussed numerically. According to the stable phase difference, the variation of the excitation resultant force from four ERs is also investigated. Finally, experiments valid the system has two synchronous states. In pre-resonance, four ERs are in-phase resulting in the linear motion of the vibrating body. However, in post-resonance, ERs along the parallel axes are in-phase, while ERs along the perpendicular axes are in anti-phase. Hence, the body remains stationary because excitation forces cancel each other out. In summary, these conclusions provide a theoretical basis for the structural design of vibratory machinery.