Proposed solutions for quantization induced performance deterioration in reset controllers

The most widely applied feedback controller is PID. This controller gains its popularity because of the ease of design through loop shaping, since PID can be analyzed in the frequency domain. However, PID is limited by linearity. Reset control is a nonlinear addition to PID control. Through linearization techniques it can be designed by analyzing the frequency domain. Through numerous numerical, analytical and practical experiments it has been shown that reset control can outperformPID. However, when practically implementing reset control, especially in motion stages, one aspect can cause severe performance degradation. Research is underrepresented in this field. Quantization can be described as discretization in the amplitude. This thesis aims to reduce the quantization induced performance degradation. Two methods are proposed: reset band and time regularization. Numerical analysis and practical experiments have been performed in order to analyze the performance degradation and proposed methods. Through the numerical analysis in matlab simulink of a mass system the performance degradation has clearly been addressed. Based on the new understanding tuning rules have been provided for both proposed methods. A preliminary sensitivity analysis shows the robustness of both methods. Both proposed methods show enhanced performance. In numerical analysis it was shown that the reset band solution and time regularization can achieve an improvement of up to 10 dB. It was shown through experiments on a high level motion stage that several dB improvement is feasible. For the reset band at a specifically detrimental frequency the error was reduced from 200 nm to 70 nm. The reset band shows an improvement of several dB. In one setup, the performance enhancement spanned a wide frequency range. Overall it is concluded that for quantization induced performance degradation both proposed methods clearly show improvement. Two novel applications of existing methods have shown an increase in performance. New tuning guidelines have been provided.CLOCMechanical Engineering | Mechatronic System Design (MSD