Intelligent motion control of linear ultrasonic motor with H∞ tracking performance

As the dynamic characteristics of the linear ultrasonic motor (LUSM) are highly nonlinear and time varying, and the model difficult to obtain, it is difficult to design a suitable controller to achieve high-precision position control using conventional control techniques. An intelligent control system using an adaptive recurrent cerebellar model articulation controller (RCMAC) is proposed for the motion control of the LUSM. In this study, by adding feedback connections in the association memory space, the proposed dynamic structure of RCMAC has superior capability to the conventional static cerebellar model articulation controller in efficient learning mechanism and dynamic response. The control laws of the intelligent motion control system are derived on the basis of the H^infin control technique so that robust tracking performance can be achieved. By using the proposed intelligent motion control system, the LUSM control system possesses the advantages of high-precision tracking performance with robustness to system uncertainties. The effectiveness of the proposed control system is verified by hardware experiments of the LUSM motion control under the conditions of uncertainties. In addition, the advantages of the proposed control scheme are indicated in comparison with an integral-proportional position control system.