Experimental and numerical comparison between two nonlinear control logics

Nonlinear behavior is present in the operating conditions of many mechanical systems, especially if nonsmall oscillations are considered. In these cases, in order to improve vibration control performance, a common engineering practice is to design the control system on a set of linearized models, for given operating conditions. The well-known gain-scheduling technique allows the parameters of the control law to be changed according to the current working condition, also increasing system stability. However, more recently new control logics directly applicable to the systems in nonlinear form have been developed. The aim of this paper is to study, both numerically and experimentally, the dynamic of a mechanical system (a 3-link flexible manipulator) comparing the performance of a fully nonlinear control (the sliding-mode control) and a standard linearized approach.