Design of nonlinear control loader system for a flight simulator (a dynamic inversion approach)

A theoretical study regarding experimental development of a nonlinear control loader system for a vertical flight motion simulator is presented. Coupled stick-aircraft dynamics during an active 3-DOF nonlinear maneuver in the vertical plane is simulated in the MATLAB SIMULINK^TM software environment that facilitates a near-exact simulation of control column displacements in response to pilot´s input, and is used as a mathematical model to actively produce the force-displacement characteristics. SIMULINK^TM model of the aircraft under study is run and free flight is considered in the atmospheric environment. A position control strategy is devised by using nonlinear dynamic inversion technique to reproduce the relevant control loads on control column of the corresponding simulator cockpit. The simulator is assumed to simulate the vertical flight motion of a general aviation aircraft. The passive feel system of the plant includes a nonlinear spring and a linear damper. The mechanical contacts of several parts of the control loading system give rise to the friction that is certainly inherent in almost every mechanical system. However, the friction is compensated by a frictional torque observer of the type proposed in the existing literature. Results of computer simulations verify the robustness of our design plan.