“…An active force control system is developed to provide an accurate real-time force loading for the landing gear of the M-346 "iron bird", which is an integrated testing rig for the simulation, confirmation, and verification of the flight controls, hydraulic system, and landing gear of the M-346 trainer, adopting the servo valve to control the hydraulic actuator, combined with a nonlinear adaptive control law to achieve precise loading controls [11]. To account for the internal and external disturbances that affect the mechanism of the loading simulator, a more accurate mathematical model, including nonlinear factors and uncertainties, advanced control algorithms (i.e., backstepping [12], sliding mode, neural network [13], iterative learning control [14]), and sensor faults and disturbances observation [15,16], is utilized for accurate tracking and nonlinear compensation. The backstepping adaptive control, combined with the modified LuGre friction model [17], is introduced into the force-tracking control of the loading simulator [18].…”