A discrete-time periodic adaptive control approach for parametric-strict-feedback systems

A periodic adaptive control approach is proposed for a class of discrete-time parametric-strict-feedback systems with unknown periodic coefficients which include the control gains. Using the information of the past few periods, the proposed adaptive controller updates the parameters periodically in a pointwise manner over one entire period. By means of backstepping design and through rigorous derivation, we show that the proposed controller guarantees the boundedness of all the closed-loop signals, and achieves the asymptotic tracking convergence. To the end, an illustrative example is presented.