Switching Gain-Scheduled Control Design for Flexible Ball-Screw Drives

This paper proposes an application of the switching gain-scheduled control technique to the flexible ball-screw drive servo system with a wide range of operating conditions. The wide operating range is caused by the change of the table position and the workpiece mass during the machining operation, and leads to plant dynamics variations. To achieve high tracking performance of the table position against the dynamics variations and the cutting force disturbance, a set of gain-scheduled controllers is designed so that each controller damps out the resonance of the ball-screw system and increases the closed-loop bandwidth for a local operating range, and tracking performance is guaranteed under the switching between these controllers. Experimental results with a laboratory-scale ball-screw drive setup demonstrate that the switching gain-scheduled controller outperforms the nonswitching one by up to 52% in tracking accuracy.