Memoryless Dynamic Output-Feedback Stabilization for Discrete-Time Closed-Loop Robot Systems With Nonlinear Uncertainties and Multiple Time-Delays

The dynamic output-feedback control problem is addressed for a class of nonlinear discrete uncertain systems with multiple time-delays. First, the system is decomposed into two subsystems based on the output and input matrix. Second, the compensator is designed for first the subsystem, and the output feedback controller is designed based on the second subsystem and compensator. Then, by choosing a Lyapunov–Krasovskii functional, we show that the developed controller makes the solutions of the closed-loop system exponentially convergent to a ball. Compared with previous work, the developed controller only depends on the system output. The design conditions of the controller are relaxed because of the proposed dynamic compensator. Furthermore, the results are extended to a general nonlinear system and a robot system. Finally, numerical examples are included to show the effectiveness of the theoretical results.