Nonlinear sampled-data controller redesign with an observer for a 3-DOF model helicopter

This paper considers redesign implementation of a nonlinear sampled-data controller for a 3-DOF model helicopter. To improve the control performance, an emulation input is modified by an additional signal. The previous study proposed a redesign method to possibly give a better control performance than emulation. However, an expected improvement cannot be obtained. This paper revises the previous method to achieve a better performance. Then, an observer is introduced to the control system because the exact values of velocity signals are not available directly.