Reduced-order disturbance observer-based adaptive reaching law control for discretized MIMO systems with unmatched uncertainties

In this paper, an adaptive discrete-time sliding mode control based on reduced-order disturbance observer is proposed for discretized multi-input multi-output systems subjected to unmatching condition. By using the designed discrete observer, a new surface constructed counteract unmatched uncertainties. Then, guarantee smaller width of quasi-sliding domain, reaching law developed, whose switching gain adaptively tuned prevent overestimation premise ensuring condition surface; meanwhile, ranges band and attractiveness region are deduced. The algorithm has low computational complexity needs no information about upper bound uncertainty. simulations bank-to-turn missile demonstrates that method can effectively reject provide higher accuracy in comparison with traditional methods.