A sampled delayed output extended state observer-based adaptive feedback control of robot manipulator with unknown dynamics

In this paper, a sampled delayed output extended state observer-based adaptive feedback controller (SDOESO-AFC) is proposed for robot manipulators under complex conditions with sampled and delayed output measurement. The overall proposed control algorithm contains a sampled delayed output extended state observer (SDOESO) to estimate the system continuous non-delayed states, and an adaptive feedback controller (AFC) to drive the robot to track the desired trajectory precisely. In the SDOESO, a closed-loop output predictor with integral delay compensation is developed to handle the sampled and delayed measurement. Using the obtained continuous non-delayed output feedback signal, an extended state observer is designed to estimate the state variables and uncertainties. In the AFC, a barrier Lyapunov function-based control algorithm is developed in conjunction with the proposed SDOESO. This algorithm employs the barrier Lyapunov function to constrain the robot manipulator's tracking errors within predefined boundaries, thereby enhancing the tracking performance. The stability of the proposed SDOESO-AFC is proved through the Lyapunov stability analysis and small gain techniques. The effectiveness of the designed SDOESO-AFC is demonstrated through the co-simulation and experimental study.