High-Precision Control of Linear Actuators Based on Internal Model Control

In recent years, a high-precision stage has received great attention due to the progress of nano-technology. This paper presents a fast-response and high-precision control method based on the internal model control in the case where the controlled object has the integral characteristic. Firstly, we refer the problems when the internal model control (IMC) is applied to the integral plant. Next, in order to overcome these problems, we introduce the disturbance observer to IMC. The disturbance observer-based internal model control (DIMC) system has the advantages of no-overshoot, easy-design and simple-realization comparing to the conventional IMC method for the integral objects. Experimental results with an ultra-precision stage demonstrate that the proposed control system achieves high-precision positioning performance with robustness to frictional disturbances.