Helicopter hover control using linear adaptive control techniques

The dynamics of a helicopter are inherently unstable, highly nonlinear and exhibit strong cross-couplings between controls. This paper is concerned with the application of linear adaptive control techniques to stabilize helicopter hover maneuvers. Linear adaptive control techniques enable the de-coupling of multiple-input, multiple-output control problems into simpler single-input, single-Output control problems. This is achieved by using disturbance accommodation control observers to estimate in real-time the effects of all the terms with the exception of nominal effects of the control terms. This approach is inherently robust because the only knowledge of the plant it requires is the approximate representation of the effects of the control. The specific challenge in this application is that, unlike aircraft applications where actuator responses can be accurately modeled, in helicopter the rotors play the role of actuators, and their responses are subject to considerable uncertainty. Numerical results presented here demonstrate that the proposed approach achieves improved tracking of commanded maneuvers, compared to traditional multi-loop designs.