Study And Design On High-reliability Eletro-machanical Actuator

Electro-mechanical actuator (EMA) is an indispensable key part in the flight control system and its reliability has an important impact on the flight safty. Research in the reliability engineering is experiencing a great transition from the early redundant stage to advanced fault-tolerant technology. In this paper, a four-phase fault-tolerant permanent magnet motor (FTPMM) is studied and used in designing a high-reliability EMA with fault-tolerant technique.As a novel motor, there is rarely any literature about the four-phase FTPMM so far, which leads to the basic research about its characters in this paper. First of all, after the study of its structure and principle, its mathematical model is presented to decouple the current, stator flux and torque of the motor. Then, we develop the simulation model to verify the performance of the decoupling control.Different from traditional there-phase SVPWM, A novel voltage space vector pulse width modulation (SVPWM) method for Four-phase FTPMM driven by H bridges is presented in this paper, and the insertion sequence of the zero vector as well as the performance sequence of the coincidence-sector is designed to convenience its DSP implementation.In order to cover the shortage of the vector control, a Neuro- Fuzzy controller is designed with the combination of fuzzy control and neural network, which is performed as the speed controller of the motor. The simulation results show that the approach outperforms the traditional PID method.After designing the fault-tolerant driver, we propose a simple and efficient scheme for fault diagnose and fault-tolerant control by taking motor, inverters and control algorithm as a whole, then a novel control stratege is developed based on SVPWM and tolerate torque control.Finally, with TMS320F2812 as the main control unit, the hardware and software of the prototype has been implemented and tested, which could adjust the double closed loop control of the EMA.The high reliability and fault-tolerance ability of the EMA based on four-phase FTPMM is confirmed with both theoretical analysis and experiments. Therefore, our research is valuable for the development of high-reliability EMA in both theoretical research and practical application.