Design and Implementation of an Embedded Controller for a Tunable Damper System

In this paper, we address the design, implementation, and experimental evaluation of a mechatronic system used to automatically adjust the damping coefficient of a small-scale bridge prototype system. This is achieved by adjusting the orifice diameters of four air dampers using a microprocessor-based controller which is interfaced with the bridge prototype using appropriate sensors and actuators. The embedded controller accepts user-defined damping coefficients as inputs and provides position commands to drive four servomotors that change orifice diameters of the dampers. The system identifies the damping coefficient using a least-squares method using displacement data collected by the load cells. The controller identifies nonlinear characteristics of the orifice damper in terms of the size of the orifice and its corresponding damping coefficient using a 3-layer neural-network. Based on that, a mapping is obtained between the orifice diameter and corresponding damping characteristics which is used to tune the system to achieve a desired damping. Details of embedded control software are presented and performance of the system is investigated using experimental evaluation.