Modeling Complex Automatic Flight Controls for Helicopter Systems

The Second Generation Helicopter Analysis System (2GCHAS) has been developed to provide a common framework for interdisciplinary design and analysis of rotorcraft systems. A current limitation is the level of sophistication available in modeling advanced control systems. Advanced Rotorcraft Technology will utilize the Phase I effort to carefully define the specifications, develop the algorithms, and implement the softwares in the 2GCHAS for the following: 1) Development of control element library of both linear and nonlinear control elements such as transfer function, limiters, deadbands, switches, time delay, etc. 2) Development of algorithm of computation of nonstructural state outputs such as vehicle attitudes, altitude, airspeed, for output feedback control. 3) Modification of assembly and solution algorithm for both decoupled and fully coupled analysis. 4) Implementation of control system analysis utilities such as Nonparametric Identification, Moving Block Average Fast Fourier Transforms, Riccati equation solutions, and Loop Transfer Recovery, and H-infinity methods. 5) Development of prototype of graphical user interface. A test method will be devised to test an advanced output feedback control system.