Genetic Optimization of Repulsive Magnetic Array Negative Stiffness Structure for High-Performance Precision Micro-vibration Isolation

Purpose: A repulsive magnetic array negative stiffness structure (RMANSS) is proposed to achieve low-frequency micro-vibration isolation with large load capacity. The RMANSS utilizes a perpendicular magnetized magnetic array to maintain the repulsive magnetic force exhibiting linear and high negative stiffness, which offsets the stiffness of vibration isolators to the maximum extent and achieves high vibration isolation performance. Methods: The theoretical model of magnetic force, stiffness and nonlinearity of RMANSS is established, and its effectiveness is validated by simulation. Based on the theoretical model, geometric parameters are optimized by the genetic algorithm. Furthermore, the performance of RMANSS is compared with three state-of-the-art magnetic negative stiffness structures. Results and conclusion: Optimized stiffness at the equilibrium position is − 29.5 N/mm, and the nonlinearity at ± 1 mm is less than 0.5‰. Both negative stiffness and linearity of RMANSS are improved by one order of magnitude than those before optimization. Comparisons with three state-of-the-art magnetic negative stiffness structures show that magnetic array not only increases negative stiffness by a factor of 2, 10 and 5, reduces nonlinearity by 93.2%, 96.8% and 93.6%, respectively, but also ensures the best vibration isolation at the equilibrium position. So, the proposed RMANSS is applicable in fields requiring high-performance vibration isolation, such as advanced manufacturing, frontier scientific research, etc.