Adaptive notch filter design for bending vibration of a sounding rocket

An adaptive notch filter design considering the body bending vibration for the attitude control of a two-stage sounding rocket is discussed in this paper. The algorithm adapts the parameter while keeping the poles of the notch filter inside the unit circle on the z plane, and thus satisfies the conditions concerning stability of the filter all the time. Only a single parameter of the filter is adapted to simplify the algorithm and thus to speed up the convergence rate. Applying this adaptive notch filter to the two-stage sounding rocket results in stable response characteristics of the attitude control system which has been unstable without adaptation. This newly designed method is simple and less CPU intensive, and is easier to implement in real-time application.