Real-time loading actuator control for an advanced aerospace test rig

The growing complexity of aircraft systems requires that extensive testing be performed on dedicated test rigs to grant the necessary flight clearance and to provide troubleshooting of the problems that may arise during prototype flight trials. A new test rig is described herein, that was recently built to provide comprehensive testing of the flight controls, landing gear, and hydraulic systems of the M-346 advanced trainer aircraft. All these subsystems are connected together on the rig as in the real aircraft to ensure that the entire system operates on the rig exactly as on the aircraft. To that purpose, a high-performance force control system was developed to provide accurate dynamic loading of the primary and secondary flight control actuators, and the structure onto which the flight control actuators are mounted provides a mechanical load path with the same stiffness as in the real aircraft. The present paper describes the main characteristics of the test rig and puts particular emphasis on the force control system that makes use of an adaptive control law to provide a very accurate control of the force acting upon the actuators during fast transients.