Function Approximation-based Sliding Mode Adaptive Control for Time-varying Uncertain Nonlinear Systems

摘要: Dead zone characteristics exist in many physical components of control systems. They are nonlinear features particularly direct current (DC) motor position tracking systems, mainly caused by the uncertain time-varying friction. can severely limit performance owing to their non-smooth nonlinearities. However, dead usually not easy be known exactly and may vary with time practical. In addition uncertainties linear part plant, controllers often required accommodate uncertainties. general, there two usual methods treating systems frictions DC The first one is separate unknown from original construct an adaptive inverse, then compensate effects (Gang & Kokotovic, 1994; Cho Bai, 1998; Wang et al., 2004; Zhou 2006). second method deal both all other as uniform uncertainty, thereupon design proper compensator (Wang 2004) or controller which counteract uncertainty(Selmic Lewis, 2000; Tian-Ping 2005). Furthermore, uncertainties' bounds remain practical This problem can't coped conventional sliding mode (Young 1999; Hung 1993) general 2006; Selmic Tian Ping 2005; Young 1993). order bound uncertainties, schemes combined technique have been developed (Chyau-An Yeu-Shun, 2001; Chyau-An Yuan-Chih, Huang Chen, Chen Huang, 2004). These transform into finite combinations Fourier series long satisfy Dirichlet condition, so that they estimated updating coefficients. Since coefficients timeinvariant, update laws easily obtained Lyapunov guarantee output error convergence. chapter devided parts. part, for we’ll propose a Function