Accurate Motion Controller Design Based on an Extended Pole Placement Method and a Disturbance Observer

Abstract

The paper describes an innovative integrated design method for accurate tracking in motion control applications, in the presence of external disturbances like friction, cutting forces, etc. First, an extended pole placement method is developed to design feedforward controllers for applications with known future input commands, like in feeddrives for machine tools. It results in a noncausal reference model with a low-pass characteristic with selectable bandwidth and zero phase shift. A new feedback design approach, based on a state and disturbance observer is introduced. A loop transfer recovery procedure tunes the observer gains to compromise optimally between performance and robustness.