Inertial properties control by variable damping actuators and application to automotive suspensions

The semi-active control of the instant centre of rotation of a 2D rigid body is investigated in the present paper by the use of controllable dampers. The use of this technique allows, in general, the chance of controlling important kinematic characteristic of the trajectory of a rigid body, by controlling the equivalent viscosity of a set of dampers. In other words, the magneto-rheological dampers can emulate variable geometry kinematic linkages through a simple instant tuning of their viscosity. The mathematical formulation passes through the application of a variational control principle. The model can be linearized and the LQR (Linear Quadratic Regulator) method can be directly applied. The optimal control solution is offered in terms of optimal instant damping coefficients required to carry the instant center of rotation of the body on a prescribed curve. The general theory is applied to automotive suspension linkages where is of interest the control of the instant roll centre axis.