Multidisciplinary Control Law Design and Flight Test Demonstration on a Business Jet

Gulfstream is using the Advanced Flight Controls Research and Development Program to develop flight controls technology within Gulfstream, including a pitch axis flight control law design applicable to an executive transport aircraft. The program includes fly-by-wire modifications to an existing airframe and flight testing of the integrated system. The flight control law development process being utilized represents a multidisciplinary application of certification requirements, control science stability requirements, piloted aircraft handling qualities requirements, and aero-servo-elastic coupling considerations. This highly integrated approach allows for simultaneous compliance with the criteria in these four areas by operating on condition-specific linear properties of the aircraft rigid-body dynamics, the aircraft sensor and control system dynamics, including time delay, and the aircraft flexible body modes. While some internal iteration at each design point is necessary, the integrated process avoids the tedious and time-consuming iteration loop typically used in which data are passed from one engineering domain to another before an acceptable design emerges. This paper describes the integrated approach to the design process, illustrates some of the design data and criteria used, and presents design results.