Design For Helicopter Control System Based On Eigenstructure Assignment

Helicopter is a complex controlled system with static instability, non-linearity, multi-variables and strong coupling. The flight control system design relates with flight mechanics, sensors, computer technology, control system and system simulation. It is of hard technology to stabilize the helicopter flight control. A helicopter is not a rigid body, but rather, it should be treated as the one with flexibility, which means that when we design the stability and control augmentation system, we should take its dynamic characters into consider. Cause the flexible deform will couple with the add-stability system; we should mount the add-stability system. Due to the special flying ability, and the requirement of it both in military and home application, it is of great real importance to analyze the aerofoil and flexible deformation. The designers should consider rotor dynamics and flexural dynamics when designing the stability and control augmentation system. In a word, the research of helicopter control technology is really important and of bright perspective.The model used in this thesis is composed of two parts: the linearized rigid dynamic and the augmented rotor dynamics and flexural dynamics. First in the thesis, we analyze the flight characteristic, control characteristic and dynamic characteristic, and then we obtain the objective equation of the helicopter control system. Second, based on order-reduced system equation, we design the control system using characteristic eigenstructure assignment and mode-matching. Third, in order to make inputs decoupled, we design the transform matrix using the method named input-output static decoupling. Finally we simulate and analyze the stability and control argumention system, and from the result we can see that stability and control augmentation system match the requirement and make the whole system a well decoupled and stable one.