|Disturbance Observer-based Adaptive Fault-tolerant Dynamic Surface Control of Nonlinear System with Asymmetric Input Saturation
Li Wang*, Hua-Jun Gong, and Chun-Sheng Liu
International Journal of Control, Automation, and Systems, vol. 17, no. 3, pp.617-629, 2019
Abstract : "In this paper, a composite fault-tolerant control problem is studied for a class of uncertain nonlinear system
with asymmetric input constraint, actuator fault and external unmatched disturbance. The radial basis function
neural network (RBFNN) is employed to approximate the unknown uncertainty and asymmetric input saturation.
The approximation error, external unmatched disturbance and actuator faults are integrated as the compounded disturbance.
A nonlinear disturbance observer is designed to tackle the effect of the compounded disturbance which
can be separated from the controller design. To handle the effect of asymmetric input saturation, a smooth continuous
differentiable saturation model is explored. Adaptive NN fault-tolerant control scheme is developed to
guarantee that all the signals in the closed-loop systems are semiglobally uniformly ultimately bounded (SGUUB)
and the tracking errors converge to a small neighborhood of origin by choosing the appropriate design parameters.
The effectiveness of the proposed control scheme is demonstrated in the simulation study."
Disturbance observer, fault-tolerant, input saturation, nonlinear system, robust control.