Development of flying qualities based charts as a support for the initialization of the gains of helicopter control laws

Helicopters are naturally (say without piloting assistance) unstable: autopilots have been introduced by industrials to assist in the piloting task. Designers have to tune the associated controllers in order to handle at best requirements from the aeronautical design standard 33. Due to the specificity of the control laws and the requirements, no analytical method exists to analyze the tuning of such controllers. In this paper, we expose analytical developments that can be used to initialize the gains of these kinds of controls laws taking into account requirements from ADS-33 standards, using simplified closed loop linear models. Results are exposed and discussed compared to complete closed loop linear results.