Toward Optimized Vibration Mitigation for Vehicle ISD Suspensions: A Fractional-Order Bridge Network Approach

To further tap into the vibration isolation potential of vehicle mechatronic ISD (Inerter–Spring–Damper) suspension systems, a positive real synthesis design method for vehicle ISD suspensions is proposed based on the fractional-order bridge networks. Firstly, a quarter-car dynamic model of the mechatronic ISD suspension system is established. Subsequently, based on the impedance solution method for bridge networks, a basic bridge network structure and its corresponding series-parallel network configuration are constructed for comparative analysis. Then, with the aim of improving the overall performance of the vehicle suspension system, the particle swarm optimization algorithm is employed to determine the optimal parameters for the mechatronic ISD suspension. Finally, simulation results under random road excitation at a vehicle speed of 20 m/s indicate that, compared to the traditional passive suspension system, the fractional-order bridge network-based ISD suspension system achieves reductions of 3.9%, 27.5%, and 11.8% in the root mean square (RMS) values of vehicle body acceleration, suspension working space, and dynamic tire load, respectively. In contrast, the integer-order bridge network-based ISD suspension system only achieves reductions of 3.0%, 24.2%, and 4.5% in these respective performance metrics. The results confirm that, with an equivalent number of components, the fractional-order bridge network exhibits superior vibration isolation performance relative to series-parallel networks, thereby providing novel methodological guidance for the design of vehicle mechatronic ISD suspension.