Algebraic Identification and Discontinuous Control for Trajectory Tracking in a Perturbed 1-DOF Suspension System

This paper deals with the output feedback control and simultaneous online algebraic identification of an unknown perturbed 1-DOF suspension system. An algebraic identifier, which is known to be of unstable nature, is provided with an automatic disconnection strategy. The automatic disconnection is achieved by assessing an extra auxiliary parameter, called the ldquosentinelrdquo parameter that monitors the convergence of the rest of the estimated system parameters. The estimated values of mass, stiffness, and damping are realized via an algebraic estimator, with great rapidity and robustness to noise process signals present in the input and output signals. A generalized proportional integral controller was designed for a trajectory tracking task and the rejection of a constant disturbance input. The switched implementation of the average input in the form of a bounded discontinuous control signal is based on the use of a Sigma- Delta modulator. In an average sense, this modulation allows us to preserve the desirable features of the dynamic output feedback controller and to be close to a real implementation. The efficiency of the complete procedure is demonstrated via digital computer simulations.