A crane-based five-axis manipulator for antenna tests. (April 2019)

• Record Type: Journal Article
• Authors: Schlott, P.; Geise, A.; Grabmair, G.; Fritzel, T.; Sawodny, O.
• Is Part Of: Control engineering practice. Volume 85(2019)
• Page Start: 149
• Page End: 162
• Publication Date: 2019-04
• Subjects: Antenna test -- Crane model -- Twisting -- Tilting -- Crane control -- Anti-sway -- 2-DOF control -- Trajectory planning -- Extended Kalman filter; Automatic control -- Periodicals; 629.89
• DOI: 10.1016/j.conengprac.2019.01.014
• Languages: English
• ISSNs: 0967-0661

Abstract

Abstract: Antenna tests require precise positioning of an RF probe — at rest and during dynamic motions. Positioning includes the actual position of the tip of this probe and its vectorial orientation. This paper presents the automation and control concept for a novel crane-based measurement system. The system consists of a measurement gondola mounted to the hook of an overhead crane and designed such that it carries the probe and rotates it about two orthogonal axes. This system allows to arbitrarily position and orientate the probe in space on a given scanning surface. As the gondola is positioned using a crane, sway, skew, and tilting oscillations must be taken into account. Therefore a control concept is proposed that extends standard crane control by two additional degrees of freedom. For motion control with good trajectory tracking behavior, a flatness-based two-degree-of-freedom (2-DOF) state controller is applied for each axis. An extended Kalman filter is used for state estimation so that nonlinear effects and coupling between different axes are considered. The effectiveness of the proposed control concept is demonstrated by means of experimental results.