High-performance robust motion control of machine tools: an adaptive robust control approach and comparative experiments

Abstract

This paper studies the high performance robust motion control of machine tools. Instead of the disturbance observer (DOB) design previously tested by many researchers, a newly proposed adaptive robust control (ARC) is applied to make the resulting closed-loop system robust to model uncertainties. Compared to DOB, the proposed ARC has a better tracking performance and transient in the presence of discontinuous disturbances such as Coulomb friction and it is of a lower-order. As a result, time-consuming and costly rigorous friction identification and compensation is alleviated and overall tracking performance is improved. The ARC design can also handle large parameter variations and is flexible in introducing extra nonlinear robust control terms and parameter adaptations to further improve the transient response and tracking performance. Anti-integration windup mechanism is built in the ARC and thus the problem of control saturation is alleviated. Extensive comparative experimental tests are performed and the results show the superior performance of the proposed ARC.