Robust helicopter position control at hover

Position control for a radio controlled helicopter at hover is carried out using H₂ and H_∞ methods. Various problems arising in real-world tests are stated and solved by different means: prefilters are used to achieve step responses without overshoot. For plants with more outputs than inputs; a special H_∞ design scheme is used. The implicit inversion of the plant in the H_∞ controller can cause problems. This inversion can be avoided by a new scheme for weighting the sensitivity.