Robust H-infinity controller with pole placement constrains in helicopter control

In this paper, the H_∞ technique with pole placement constraints is used to design the CH-47 helicopter controller. The benefits from this are that the system not only has satisfied the H _∞ requirement but also can force the closed-loop poles into a suitable sub-region of the left-half plan. It avoids over fast dynamic responses for digital implementation and has satisfied damping. In our design, the following problems are considered: How to choose the controller structure? How to design the weighting functions? Should the uncertainty be defined in the input or output? The paper gives the answers to these questions. The simulation results show that the system designed satisfies the ADS-33 requirement and robustness stability