Electro-Hydrostatic Actuator Controller Design Using Quantitative Feedback Theory.

The Electro-Hydrostatic Actuator EllA technology offers a higher degree of combat survivability and easier maintainability of the aircraft flight control system, because all the components necessary to operate the actuator are collocated with the actuator. Quantitative Feedback Theory QFT is used to design a control system for the EHA. The impact of parameter variations, sensor noise, and flight conditions are explicitly considered in the design process. The solution utilizes a two loop QFT feedback structure. The inner loop structure stabilizes the motors angular velocity and decreases the outer loops uncertainty. The outer loop structure controls the RAM pistons position to track the input command. The resulting design is not only robust with respect to plant parameter variations, but is also insensitive to the effects of sensor noise. The actuators phase lag is reduced by incorporating phase constraints in the QFT design paradigm. QFT is shown to be a viable tool in solving a real-world problem.