Design of nonlinear lag-lead compensators by extended linearization using symbolic computation techniques

Abstract

In this paper we report the development of NLLag-Lead, a symbolic computation tool allowing to automate the design of linear and nonlinear lead, lag and lag-lead compensators, for nth ordersingle-input single-output nonlinear dynamical control systems. The proposed nonlinear lag-lead compensators are straightforward structural nonlinear extensions of appropriate state variables representations of the linear lag-lead compensators, which for nonlinear extension purposes are represented as a cascade of an input PD like controller followed by an output first order linear dynamical system. This two-blocks decomposition transforms the design of a nonlinear extension of a lag-lead compensator into the design of a nonlinear PD controller and a nonlinear state-feedback controller. NLLag-Lead has been computationally implemented using Mathematica® as symbolic computational platform