Semiactively Controllable Vehicle Seat Suspension System with Negative Stiffness Magnetic Spring

This article proposes an innovative controllable seat suspension with a long stroke negative stiffness (NS) spring for reducing the whole-body vibration of heavy vehicle drivers. The proposed seat suspension is mainly composed of a NS magnetic spring (NSMS), a coil spring, and an electromagnetic damper for semiactive vibration control. In this way, the system characteristic induced by the NSMS can be maximally utilized to improve ride comfort. Property tests are conducted to validate the mathematical modeling and the constructed system stiffness characteristic. Based on the derived dynamic model, a prescribed performance control technique with closed-loop stability is employed to guarantee both the transient and steady-state responses under the predefined levels. Experiments are implemented where the transient and random vibration signals are applied on the seat suspension base. The results illustrate that when compared with a commercial seat product, an increasing convergence rate by 16% and a decreasing frequency-weighted root-mean-square value by 34% are achieved.