The problem of automatically controlling the stationary position in hovering fligh of a load suspended from a helicopter is first outlined with reference to some of the past and present-day flight-control systems designed to achieve its solution. Next, a detailed mathematical model of a particular helicopter-and-load combination is described before a discussion of a proposed control system to provide optimal load positioning, even in the presence of acute atmospheric turbulence. Some numerical problems that can arise in the determination of such solutions are indicated, and several results are discussed which illustrate the effectiveness of the proposed scheme.
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