Semi-Active Suspension Control with LPV Mass Adaptation*

A novel control system for an automotive semi-active suspension based on a Quarter of Vehicle (QoV) model is proposed. In typical conditions the mass of the vehicle body varies due to several variables, such as the number of passengers, the vehicle load, etc. These variations can lead to undesirable responses even if the controller was adequately tuned using a nominal model. In order to improve this situation a controller which actively adapts to vehicle body mass variations can be used. In this article a control scheme based on the Linear Parameter-Varying (LPV) framework is proposed. This approach considers the nonlinear behavior of the damper and variations on the sprung mass as scheduling parameters. The vehicle body mass is online estimated using the Recursive Least Squares algorithm. Simulations of a QoV model of a pickup truck which includes an experimental magneto-rheological damper model were carried out in order to evaluate the proposed scheme. Results in the frequency and time domain show the effectiveness of the proposed controller compared to an uncontrolled damper and a standard LPV controller without mass adaptation. The comfort is improved over 25% using the proposed scheme when the vehicle body mass changes.