High-Order Compensator Augmentation of a Baseline Partial Authority Controller for Rotorcraft

An architecture and design methodology for high-order compensator (HOC) augmentation of a baseline controller for rotorcraft is presented. With this architecture, the HOC compensator is selectable and can easily be authority limited, which might ease certification. Also, the plant for this augmentative multi-input multioutput compensator design is a stabilized helicopter system, so good flight-test data could be safely gathered for more accurate plant identification. The design methodology is carried out twice on an example helicopter model, once with turbulence rejection as the objective, and once with the additional objective of closely following pilot commands. The turbulence rejection HOC is feedback only (HOC_FB), while the combined objective HOC has both feedback and feedforward elements (HOC_FBFF). The HOC_FB was found to be better at improving turbulence rejection but generally degrades the following of pilot commands. The HOC_FBFF improves turbulence rejection relative to the baseline controller, but not by as much as HOC_FB. However, HOC_FBFF also generally improves the following of pilot commands.