Adaptive NN control for discrete-time pure-feedback systems with unknown control direction under amplitude and rate actuator constraints

• Published in: ISA transactions Vol. 48; no. 3; pp. 304 - 311
• Main Author: Chen, Weisheng
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.07.2009; Elsevier
• Subjects: Adaptative systems; Algorithms; Applied sciences; Computer science; control theory; systems; Computer Simulation; Control system analysis; Control system synthesis; Control theory. Systems; Discrete Nussbaum gain; Exact sciences and technology; Feedback; Implicit function theorem; Models, Theoretical; Neural network; Neural Networks (Computer); Pure-feedback systems; Quality Control; Time Factors; Implicit function theorem; Pure-feedback systems; Neural network; Discrete Nussbaum gain; State feedback; dynamic control; Saturation; Control program; Feedback regulation; Tracking task; Mean value; Adaptive control; Closed feedback; Radial basis function; Neurocontrollers; Discrete time; Distributed control; Tracking error; Non affine transform; Output feedback; State constraint
• ISSN: 0019-0578; 1879-2022; 1879-2022
• DOI: 10.1016/j.isatra.2009.04.002

This paper focuses on the problem of adaptive neural network tracking control for a class of discrete-time pure-feedback systems with unknown control direction under amplitude and rate actuator constraints. Two novel state-feedback and output-feedback dynamic control laws are established where the function tanh ( ⋅ ) is employed to solve the saturation constraint problem. Implicit function theorem and mean value theorem are exploited to deal with non-affine variables that are used as actual control. Radial basis function neural networks are used to approximate the desired input function. Discrete Nussbaum gain is used to estimate the unknown sign of control gain. The uniform boundedness of all closed-loop signals is guaranteed. The tracking error is proved to converge to a small residual set around the origin. A simulation example is provided to illustrate the effectiveness of control schemes proposed in this paper.