Semi-active suspension control using "fast" model predictive control

The problem considered in this paper is the design and the analysis of a control strategy, for semi-active suspensions in road vehicles, based on model predictive control (MPC) techniques. The computed control law, using predictive techniques aims to optimize, the suspension performance, by minimizing a quadratic cost function while ensuring that the magnitude of the forces generated by the control law satisfies the physical constraints of passive damping. The on line computation difficulties related to the predictive control law are overcome by means of a "fast" implementation of the MPC algorithm (FMPC). The estimation of the system state variable needed for control law computation is provided by a suitable "robust" observer, whose accuracy is not affected by variation of the system parameters (i.e. masses, damping and stiffness coefficients, etc.). A performance comparison with the well established semi-active sky-hook strategy is presented. The achievable performance improvements of the proposed design procedure over sky-hook control law are showed by means of simulation results.