Design And Evaluation Of A Stochastic Optimal Feed Forward And Feedback Technology Sofft Flight Control Architecture PDF Download

A new control design methodology is developed: Stochastic Optimal Feedforward and Feedback Technology (SOFFT). Traditional design techniques optimize a single cost function (which expresses the design objectives) to obtain both the feedforward and feedback control laws. This approach places conflicting demands on the control law such as fast tracking versus noise atttenuation/disturbance rejection. In the SOFFT approach, two cost functions are defined. The feedforward control law is designed to optimize one cost function, the feedback optimizes the other. By separating the design objectives and decoupling the feedforward and feedback design processes, both objectives can be achieved fully. A new measure of command tracking performance, Z-plots, is also developed. By analyzing these plots at off-nominal conditions, the sensitivity or robustness of the system in tracking commands can be predicted. Z-plots provide an important tool for designing robust control systems. The Variable-Gain SOFFT methodology was used to design a flight control system for the F/A-18 aircraft. It is shown that SOFFT can be used to expand the operating regime and provide greater performance (flying/handling qualities) throughout the extended flight regime. This work was performed under the NASA SBIR program. ICS plans to market the software developed as a new module in its commercial CACSD software package: ACET. Halyo, Nesim and Direskeneli, Haldun and Taylor, Deborah B. Unspecified Center AIRCRAFT CONTROL; AIRCRAFT PERFORMANCE; CONTROL SYSTEMS DESIGN; F-18 AIRCRAFT; FEEDBACK CONTROL; FEEDFORWARD CONTROL; FLIGHT CONTROL; OPTIMAL CONTROL; STOCHASTIC PROCESSES; APPLICATIONS PROGRAMS (COMPUTERS); FLIGHT CHARACTERISTICS; SENSITIVITY...