High-performance direct-drive flight actuators: advanced technology demonstration

A concept in design of fly-by-wire actuator systems is developed to be implemented in advanced flight vehicles. To attain the specified vehicle performance, highly reliable flight actuators are needed to be deployed. To satisfy severe requirements on weight and size, efficiency and torque density, steady-state and dynamic characteristics, ruggedness and reliability, survivability and maintenance, novel flight actuator systems are developed using high-performance stepper motors with advanced power electronics controlled by microprocessors. It is illustrated that the desired performance and integrity are guaranteed. Weight and size are decreased, reliability and survivability are increased, by using the advanced actuator technology reported. Permanent-magnet stepper motors can be directly attached to control surfaces, and redundancy needed is achieved. This solution enhances the reliability by eliminating geartrains and ensures compact, highly integrated assembling compared with the existing actuators. Permanent-magnet stepper motors are needed to be controlled. A new design method is reported to design control laws, and the Lyapunov stability theory is used to prove the robust stability and tracking as well as to find the feedback coefficients. It is illustrated that innovative control algorithms are designed based upon the electric machinery features to maximize the electromagnetic torque developed. Experiments have been performed to illustrate the effectiveness and feasibility of direct-drive actuator technology