TIME-DELAY CONTROL WITH STATE-FEEDBACK FOR AZIMUTH MOTION OF THE FRICTIONLESS POSITIONING DEVICE

A time delay controller with state feedback is proposed for azimuth mo tion control of the frictionless positioning device which is subject t o the variations of inertia in the presence of measurement noise, The time delay controller, which is combined with a low-pass filter to att enuate the effect of measurement noise, ensures the asymptotic stabili ty of the closed-loop system, It is found that the low-pass filter ten ds to increase the robustness in the design of the time delay controll er, as well as the gain and phase margins of the closed-loop system, N umerical and experimental results support that the proposed controller guarantees a good tracking performance, irrespective of the variation of inertia and the presence of measurement noise.