Design of $$\varvec{\upalpha }$$ α -filter-based UDE controllers considering finite control bandwidth

Abstract

Recently, a new first-order α-filter for uncertainty and disturbance estimator-based control was proposed to achieve reduced tracking and estimation errors in the presence of fast-varying uncertainties and shown to be capable of keeping the steadystate error within acceptable limits by appropriately choosing filter parameters. The purpose of this note is to demonstrate operation limits of the new filter and quantify performance enhancement by taking practical implementation issues and restrictions into account.

Uncertainty and disturbance estimator-assisted control of a two-axis active magnetic bearing

“…Since R(s) is a low-pass filter, Z s ð Þ should be selected as a high-pass filter in order to allow decent attenuation of the lumped uncertainty throughout the whole bandwidth, e.g. keeping the overall gain below the predetermined maximum allowed value K, as shown in Figure 4 (Kuperman 2015).…”

“…The UDE functionality is based on the assumption that an appropriate filtering can approximate a continuous signal. UDE theory has been further elaborated (Chandar et al, 2014;Deshpande et al, 2012;Kuperman 2015;Zhong et al, 2011) and successfully applied to systems with time delays (Kuperman et al, 2011;Stobart et al, 2011), robust input-output linearization (Talole et al, 2010(Talole et al, , 2011, a model following sliding mode control (Talole et al, 2008), robust control of aircraft (Kuperman et al, 2013(Kuperman et al, , 2015Su et al, 2011Su et al, , 2013 and missile guidance (Phadke et al, 2012).…”

Uncertainty and disturbance estimator with improved steady‐state performance for grid‐connected power converters

“…Correct filter design allows accurate TUD estimation and subsequent cancellation, yielding outstanding disturbance rejection performance. Basic analysis and design of TUDE-based controllers were revealed in [8][9][10][11][12][13][14][15] and applied to various practical systems in [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34]. TUDE-based control was recently applied to the field of power electronics and motor drives as well [35][36][37][38][39].…”

Uncertainty and Disturbance Estimator-Based Backstepping Control for Nonlinear Systems With Mismatched Uncertainties and Disturbances

“…The reference model with the error feedback gain matrix determines the system output performance, and the filter design determines the performance of uncertainties and disturbances rejection. Due to the importance of the filter design, Shendge and Patre, Chandar and Talole, Kuperman, and Ren et al [9][10][11][12] have discussed how to improve the filter design in the UDE-based control to achieve a better disturbance rejection performance. In Ref.…”