Hierarchical modeling control of a motorcycle semi-active suspension with six degree-freedoms

Hierarchical control is a new control framework in vehicle vibration control field. In this paper, a hierarchical modeling method is provided to construct a different motorcycle model compared to traditional model with six degrees of freedom (DOF) so as to design a hierarchical modeling control. The whole control framework is composed of a center control, two local controls and two uncontrollable parts. The front and rear wheel systems of a motorcycle are all dealt with two independent local 2-DOF systems. The driver and engine are acted as uncontrollable passive parts. The center control formed by an algorithm make up of some dynamic equations that harmonize local relations are deduced. The vertical and pitch accelerations of the suspension center are treated as center control objects. In example, a real time Linear Quadratic Gaussian (LQG) algorithm is adopted by two local controls, respectively. The results of simulation show that the hierarchical modeling control has less CPU time to depress response lag and improve ride quality.