Improved Suspension Parameter Optimization for High-Speed Railway Vehicles with Inboard Bogies

This study proposes an improved suspension optimization methodology for high-speed inboard bogies. Previous research employed a multi-objective genetic algorithm to minimize bogie and carbody accelerations, based on 550 km/h simulations on straight and curved tracks under worn wheel conditions. However, that approach did not fully account for manufacturing constraints, and often yielded over-designed specifications that struggled to balance ride comfort and critical speed. To address these limitations, this study retains the existing optimization framework but redefines the objective functions as maximizing the minimum damping ratio of vibration modes under new wheel conditions, and maximizing critical speed under worn wheel conditions. By incorporating realistic design constraints to ensure practical feasibility, the newly proposed approach successfully achieves both the desired ride comfort and critical speed targets simultaneously.