High Bandwidth Control of Ball Screw Drives

This paper presents a tracking control strategy for high speed ball screw drives. Rigid body motion is controlled using adaptive sliding mode control. Torsional vibrations are modeled, experimentally identified, and compensated in the control law using notch filtering and active cancellation techniques. Attenuation of torsional resonances improves the stability margins and enables high positioning bandwidth to be achieved. The axis friction is experimentally identified and cancelled out in feedforward, in order to improve the positioning accuracy at motion reversals. The developed control law is verified experimentally on a high speed ball screw drive, where a tracking accuracy of 1.6 um is maintained while traversing the axis at 1000 mm/sec feed and 1 g acceleration.