Design of active suspension systems is well known, however the notion of control bifurcations for the design of such systems has been introduced recently. A nonlinear active suspension system consisting of a magneto-rheological damper is analyzed in this work. It is well known that a parameterized nonlinear differential equation can have multiple equilibria as the parameter is varied. A local bifurcation of a parameterized nonlinear system typically happens because some eigenvalues of the parameterized linear approximating differential equation cross the imaginary axis and there is a change in stability of the equilibrium. The qualitative change in the equilibrium point can be characterized by investigating the projection of the flow on the center manifold. A control bifurcation of a nonlinear system typically occurs when its linear approximation loses stabilizability. In this work the control bifurcations of a magneto-rheological fluid based active suspension system is analyzed. Some parametric results are presented with suggestions on how to design nonlinear control based on the parametric control bifurcation analysis as applied to the design of an active suspension system.
Multi-Modes Control for Semi-Active Suspension Systems