Output Delay Systems Tracking Using System Centre Approach and Sliding Mode Control

Output tracking in SISO fully linearizable nonlinear systems with an output time delay is considered using sliding mode control and the system centre approach. Using Padé approximations for the delay, the problem is reduced to the tracking of a nonminimum phase control system. This system is transformed into a corresponding state tracking problem, where the state tracking profiles are generated by the equations of the stable system centre. The sliding mode control approach is developed and numerical examples are presented. Also the describing function is used to evaluate the limit cycle generated by the feedback of the actual delayed output and these results agree very closely with the system simulations.