Discrete-time flatness-based control of a gantry crane. (February 2022)

• Record Type: Journal Article
• Authors: Diwold, Johannes; Kolar, Bernd; Schöberl, Markus
• Is Part Of: Control engineering practice. Volume 119(2022)
• Publication Date: 2022-02
• Subjects: Discrete-time flatness -- Discretization -- Nonlinear control -- Dynamic feedback linearization -- Quasi-static feedback linearization -- Optimization; Automatic control -- Periodicals; 629.89
• DOI: 10.1016/j.conengprac.2021.104980
• Languages: English
• ISSNs: 0967-0661

Abstract

Abstract: This article addresses the design of a discrete-time flatness-based tracking control for a gantry crane and demonstrates the practical applicability of the approach by measurement results. The required sampled-data model is derived by an Euler-discretization with a prior state transformation in such a way that the flatness of the continuous-time system is preserved. Like in the continuous-time case, the flatness-based controller design is performed in two steps. First, the sampled-data system is exactly linearized by a discrete-time quasi-static state feedback. Subsequently, a further feedback enforces a stable linear tracking error dynamics. To underline its practical relevance, the performance of the novel discrete-time tracking control is compared to the classical continuous-time approach by measurement results from a laboratory setup. In particular, it turns out that the discrete-time controller is significantly more robust with respect to large sampling times. Moreover, it is shown how the discrete-time approach facilitates the design of optimal reference trajectories, and further measurement results are presented.