High-precision multi-shuttle operation of a segmented stator permanent magnet linear synchronous motor

Abstract

Due to their high performance and flexibility, permanent magnet linear synchronous motors (PMLSMs) are widely used in industrial systems. Innovative motor designs incorporate stator segments with varying curvatures, enabling the realization of complex PMLSM geometries. One key advantage of PMLSMs is their capability to operate multiple moving units (shuttles) independently and simultaneously, enhancing system flexibility and throughput. However, the segmented stator design and the close-proximity operation of multiple shuttles introduce additional control challenges. These stem from interactions between the shuttles’ permanent magnets (PMs), overlapping current patterns, and manufacturing and mounting tolerances. High-precision position tracking is critical in industrial applications such as manufacturing processes. This paper proposes a real-time capable correction method to mitigate the impact of overlapping currents on the shuttles’ tractive force. A two-degree-of-freedom position controller is augmented with an iterative learning control (ILC) strategy to achieve high-precision position tracking of multiple shuttles operating in close proximity. Experimental results demonstrate excellent tracking performance along the entire curvilinear track within segments and at segment transitions while consistently maintaining the desired shuttle spacing, even for very small distances.