Equations of motion are derived for general slung load systems. Systematic approaches have not previously been studied for deriving slung load dynamic models, hut an interest in simulation, analysis, and control for slung loads carried by two o r more helicopters motivates attention to this topic. Slung load systems a r e approximated as several rigid bodies connected by suspensions consisting of straight line cables and links which can be assumed elastic o r inelastic and which transmit force only along the link. Equations for the general system are obtained from the Newton-Euler equations with the introduction of generalized speeds. Several systematic formulations are given which generalize previous case-specific results from the slung load literature or occur in the existing literature on the dynamics of multibody systems. A novel formulation is derived for inelastic suspensions from the elastic suspension equations and in which the constraint forces appear explicitly. The result is computationally more ellicient for slung loads than the other formulations, is readily combined with the elastic suspension equations in a single simulation, and is readily applied to complex dual and multilift systems. The new formulation is applied to a Cbody dual lift system. Simulation equations are given along with a review of issues related to simulation of the dynamics, and numerical results. NotationA. B matrices from the kincmaticsv = Au +Bpoftheunconstrained system Al, L partition of A into the Jacobians dv/dul, dv/d .

No abstract