MODEL PREDICTIVE CONTROL OF A HYDRAULIC ACTUATOR IN TORQUE APPLYING SYSTEM OF A MECHANICALLY CLOSED-LOOP TEST RIG FOR THE HELICOPTER GEARBOX

Abstract

Transmission health is an important factor in safety and maintenance costs in industries, so construction of test rigs for testing high-powered gearboxes under different operating conditions of helicopters is required. The studied test rig, which is developed at Sharif University of Technology branch of ACECR (Academic Centre of Education, Culture and Research) is mainly used for testing high-powered gearboxes through a mechanically closed-loop procedure. For providing a variety of speeds and torques in test rigs, torque applying system is required. According to generation of higher forces, reduced size of equipment and accurate positioning, electro hydraulic actuators (EHAs) are used for applying torques for planetary gearboxes of this test rig. Due to the importance of applying accurate torques in evaluation of the gearbox performance, first an accurate model of EHA is derived, which captures the system dynamics using system identification method with low consumed time and simple relations. After that, a type of model predictive controller called dynamic matrix controller is proposed for controlling EHA under determined requirements. Then, the performance of proposed controller under normal conditions as well as in presence of disturbance is investigated. The results show a good tracking of controller for various reference inputs in different conditions. Moreover, the performance of the proposed controller is compared with the performance of classical proportional-integral-derivative (PID) controller and superior characteristics of the proposed controller is concluded.