Adaptive control of linear systems with poles in the closed LHP with constrained inputs

We propose an indirect adaptive control strategy for possibly nonminimum phase systems but having poles in the closed left hand plane (LHP). The adaptive control is based on a control law for systems with amplitude-constrained inputs. Several simulations performed on different second order systems show that the control scheme brings the state of the system to the origin using a control input with arbitrary bounds. The simulation results presented do not require excitation of the system or projection of the parameter estimates into the admissible region, however this may not be the general case. Extension of the proposed strategy to higher order systems is feasible. The approach based on excitation presents no particular problem to cover higher order systems, nevertheless the approach based on projecting the estimates into the admissible region becomes more complex as the order of the system increases