Development of No-Back Mechanism Models for Electrical THSA Based on Experimental Study

With the rapid development of power-by-wire technology applied in flight controls, electro-hydrostatic actuator (EHA) and electromechanical actuator (EMA) are preferred to the application of primary flight controls. Electrical trimmable horizontal stabilizer actuator (THSA) is a novel type of actuator with the function of fault tolerance that is different from common EMA. THSA can avoid mechanical path failure and prevent the load from driving backward and impacting the power grid by utilizing no-back mechanism. This paper focuses on the study of no-back mechanism by introducing a novel type of friction disc of skewed roller friction disc (SRFD). Firstly, the mathematical model of the no-back device and the SRDF is introduced, and the friction performance under different working conditions is studied based on experimental ways. Then the realistic no-back model is established and the friction coefficient data from the test is obtained. The simulation results show that this model is reliable, and the model can be expected to be applied in THSA system-level model.