Accurate tracking controller design for high-speed drives

This paper presents a motion control strategy that utilizes a combination of vibration avoidance, sliding mode control, and torque ripple and friction compensation techniques to facilitate high bandwidth–high accuracy tracking in ball screw drives. Torsional vibrations are modeled with finite element analysis and experimentally identified. Excitation of the first and second mode is avoided by designing appropriate notch filters. Following the attenuation of structural vibrations, rigid body motion is controlled using adaptive sliding mode control, where a positioning bandwidth of 223 Hz is achieved. Nonlinear friction and motor/mechanical torque ripples are modeled and compensated in feedforward. With the proposed control strategy, an experimental tracking accuracy of 0.95 μm has been achieved while traversing the axis at a feedrate of 1000 mm/s with 1g acceleration.