Adaptive compensation control of an electromagnetic active suspension system based on nonlinear characteristics of the linear motor

With the electrification and intellectualization of vehicle systems, electromagnetic active suspension has been paid more and more attention. Linear motor is one of the effective actuators of the electromagnetic active suspension system. The nonlinear factors of linear motor, such as nonlinear friction force and ripple force, as well as power limit and magnetic saturation, will reduce the performance of electromagnetic active suspension. However, the current research rarely considers the effect of these nonlinear factors on active suspension control. In this article, the effect of nonlinearities of linear motors on electromagnetic active suspension performance and the ways to improve their performance are studied. An adaptive filtering compensation method is proposed to reduce the influence of nonlinear factors on the electromagnetic active suspension control. According to the simulated calculations, performance degradation of the active suspension is observed in both the primary control objective and high-frequency range due to inherent disturbance from the nonlinear factors. Also, the electromagnetic nonlinearities will reduce the active suspension effective force output. By proposing an adaptive compensator based on the filtered-x recursive least squares algorithm, the first-order resonance of the suspension system could be controlled and the electromagnetic active suspension effective force could be magnified. Also, convergence of the adaptive compensator is found to be rapid and reasonable.