Fault Tolerant Control for a Second Order LPV System using Adaptive Control Methods*

A Fault Tolerant Control (FTC) reconfigurable structure for a second order nonlinear process is developed. This structure is based on a Model Reference Adaptive Control (MRAC) with a H∞Gain Scheduling controller designed using an Linear Parameter- Varying (LPV) system: MRAC-H∞GS-LPV. The MRAC-H∞GS-LPV was compared with a structure named MRAC-LPV that is based on an MRAC design using an LPV system. A coupled-tank system is used as testbed in which different types of faults (abrupt-additive fault, gradual-additive fault and multiplicative fault) with different magnitudes and different operating points were tested. Results showed that the use of an H∞GS controller in combination with an MRAC improves the FTC performance because fault accommodation is faster. In addition, the structures based on Lyapunov theory were able to deal more efficiently with the faults and the changes in the operating points of the nonlinear model of the system.