Model Identification and H∞ Control of an Aeropendulum

Abstract

The aeropendulum is a nonlinear system that consists of a rod equipped with a motorized propeller at one of its ends and connected to a pivot at its other end. This pivot receives a torsional moment through the aerodynamic effects generated by the propeller thrust force. From a control point of view, the aeropendulum is a plant that imposes a significant complexity on the design of controllers. In view of that, this system can be used in didactic observations and real applications of control theory concepts. This work presents the model identification and  control of an aeropendulum system prototype. The model has as control input the voltage applied to the motor that drives the propeller and the rod angle as system output, measured by an incremental encoder. The identification process was conducted using the ident function of the Matlab^® software. Based on the obtained model, an  controller was designed to stabilize the system around the operating point, maintaining the rod in a specific position. A square wave was used as a reference for the angular variation of the rod to verify the controller's efficiency in tracking a required angular trajectory. Simulation and experimental tests were conducted to validate the obtained mathematical model and the controller design. The results confirmed that the considered methodology was satisfactory for the studied case.