Output feedback control of uncertain Euler-Lagrange systems by internal model

In this paper, we investigate the trajectory tracking control problem of a class of uncertain Euler- Lagrange systems subject to disturbances. In sharp contrast to existing approaches where the position, the velocity, and the acceleration of the reference trajectory are assumed to be measurable, we propose a class of dynamic output feedback control laws which depends on the tracking error of the position and that of the velocity. Specifically, by characterizing the reference trajectory and the disturbances with an exosystem, we design an internal model to learn the desired feedforward input such that the reference trajectory can be tracked in spite of unknown system parameters and disturbances. The effectiveness of the proposed approach is illustrated by its application to trajectory tracking control of a three-link cylindrical robot arm.& COPY; 2023 Elsevier Ltd. All rights reserved.

Automated summary

In this paper, the trajectory tracking control problem of a class of uncertain Euler-Lagrange systems subject to disturbances is investigated. Unlike existing approaches, a class of dynamic output feedback control laws that depend on the tracking error of the position and velocity are proposed instead of assuming the measurability of the reference trajectory's position, velocity, and acceleration. By characterizing the reference trajectory and disturbances with an exosystem, an internal model is designed to learn the desired feedforward input, allowing the tracking of the reference trajectory despite unknown system parameters and disturbances. The effectiveness of this approach is demonstrated through its application to trajectory tracking control of a three-link cylindrical robot arm.