The extended Bouc-Wen differential model is one of the most widely accepted phenomenological models of hysteresis in mechanics. It is routinely used in the characterization of nonlinear damping and in system identification. In this paper, the differential model of hysteresis is carefully reexamined and two significant issues are uncovered. First, it is shown that the unspecified parameters of the model are functionally redundant. One of the parameters can be eliminated through suitable transformations in the parameter space. Second, local and global sensitivity analyses are conducted to assess the relative sensitivity of each model parameter. Through extensive Monte Carlo simulations, it is found that some parameters of the hysteretic model are rather insensitive. If the values of these insensitive parameters are fixed, a greatly simplified model is obtained.

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For many types of cranes commonly used in technical applications, the reduction of payload pendulations is an important design issue. Especially for cranes with variable cable length, oscillations are boosted by the hoisting of the payload due to nonlinear effects. Most of the techniques for active damping are based on a control input that displaces the support of the hoisting mechanism perpendicularly to the direction of the pendulum. However, controlled motion of the carrying structure might not be suitable or even impossible for some applications.The possibility to influence and reduce pendulations by means of feedback controlled variations of the cable length is hardly used in crane technology. A control strategy based on the phenomenon of autoparametric resonances in nonlinear dynamical systems is presented that manipulates the desired hoisting velocity by superposition of a suitably modulated motion in order to reduce amplifications of the pendulations, in particular in absence of other effective control inputs. Experimental results for a simple pendulum setup are presented.

A control strategy for hoisting drives of crane systems is discussed. Based on modal coupling control, the desired hoisting velocity is manipulated by superposition of a suitably modulated motion in order to suppress the so–called spaghetti–problem of hoisting–induced pendulations. For a 3–dimensional multibody system featuring the flying–crane –concept the extension of this control strategy to more complicated systems is exemplified. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)