Semi-dual loop control of two-mass actuator system using Luenberger state observer

Dual loop method is a standard motion control strategy to account for nonlinearities between the motor and load and thus to improve the load positioning performance. However, when dispense with motor-side sensing, which can be cost and space saving, a single load-side feedback can lead to disturbing vibrations or even instabilities. In this paper, a semi-dual loop control of two-mass actuator system is proposed which uses the Luenberger state observer to feedback the motor-side velocity without sensing. A linear state-space model is identified in frequency-domain from the experimental data and serves for observer and control design. The observer-based inner control loop is conceptualized for stabilizing the motion system. The outer I-control loop is determined so as to achieve a precise load positioning. The designed control system is evaluated experimentally on the two-mass actuator with gear elasticities and serves as a prototype for future developments.