CONTROL REQUIREMENTS FOR SLING-LOAD STABILIZATION IN HEAVY LIFT HELICOPTERS.

Abstract

Linearized equations of motion of the helicopter/winch/cable/load complex are developed for a level flight condition at constant airspeed and for a variable suspension geometry. These equations are then used in conjunction with modern control theory to design several control systems, each of which stabilizes the load for a given type suspension. Load stability, winch power requirements and the dynamic performance of the winch controlled systems are then compared against (one, two or three) fixed point designs.