Robust Adaptive Control Applied to Chua's Circuit

Many practical systems (for example: robotic systems, power system and electronic circuits) are multiple-input multiple-output nonlinear systems and some of them have coupled relations between inputs and outputs. Besides all that, these systems can suffer from plant uncertainties and external disturbances. Any control techniques to be applied to these systems are complex. This work proposes a new control structure, based on the union between the variable structure model reference adaptive control and a decouple left-inverse technique, to transform the nonlinear multiple-inputs multiple-outputs system into a number of single-input single-output linear systems. In that case each input affects only one output and with a desired closed-loop performance. The proposed structure uses only input/output measurements, improves the transient performance (reducing the output “chattering”) and it is robust to parametric uncertainties and disturbances. All these features are demonstrated by simulation results of a simple electronic circuit that exhibits chaotic behavior (Chua’s circuit). The proposed structure may be used to smooth the control signal, thus reducing the chattering in the output signal.