Helicopter Maneuverability Control Using Nichols Chart

The three degree of freedom helicopter system is a laboratory sized helicopter model normally used as a benchmark example for a multivariable control system. The paper proposes the design of a robust controller for the position control of three degree of freedom flight dynamics of a freedom helicopter using the technique of Nichols chart (Quantitative Feedback theory). A robust controller and prefilter is designed for the pitch axis for achieving the frequency domain tracking criteria and robust stability conditions. Pertinent results have been achieved for the required stability and tracking criteria.