Design optimization of variable inerter based on vehicle suspension performance criteria

Inerter, a mechanical two-terminal component that has force proportional to relative acceleration between its two terminals, has recently emerged as a promising suspension element to vehicle suspension systems. However, previous research studies have shown that the suspension improvement offered by a passive inerter is marginal. To address this limitation, this paper proposed a novel design of variable inerter, providing non-linear characteristic. However, the design of such a variable inerter poses challenges, specifically in determining unknown design parameters. With the goal of maximizing the suspension performance improvement, a multi-objective optimization approach is carried out to determine the optimal suspension performance improvement provided by a variable inerter based on quarter vehicle model. The optimization framework involves minimizing vehicle suspension performance criteria, such as vehicle body acceleration and dynamic tire load. Both aspects affect the ride comfort and road holding ability of a vehicle to ensure the passengers’ safety. The variable inerter is applied to both typical passenger car and heavy vehicle such as truck and the simulation result showed that a variable inerter outperforms passive inerter in both cases. Notably, the suspension performance improvement achieved in heavy vehicles is more substantial when compared to passenger cars. Therefore, the implementation of variable inerter in vehicle suspensions is proved to be beneficial.