Adaptive super-twisting control for leader-following consensus of second-order multi-agent systems based on time-varying gains

In this paper, robust distributed consensus control is designed based on adaptive time-varying gains for a class of nonlinear multi-agent systems (MAS) in the presence of uncertain parameters and external disturbances with unknown upper bounds. Due to various conditions and constraints, different dynamical models for the agents can be considered in practice. On the basis of a continuous homogeneous consensus method which has been proposed for the nominal nonlinear MAS, the discontinuous and continuous adaptive integral sliding mode control strategies are particularly designed and extended to accomplish exact and precise consensus for non-identical MASs influenced by imposed perturbations. However, it is noted that in practical problems, the exact upper bound of perturbations is unknown. Then, the proposed controllers have been improved in an adaptive scheme to overcome this drawback. In addition to the adaptive estimation strategy and time-varying gains, which address considered uncertain parameters in the dynamics of the following agents, the designed distributed super-twisting sliding mode strategy for nonlinear agents adjusts the gain of the control inputs and guarantees that the proposed protocol performs properly without any setbacks of the chattering phenomenon. The illustrative simulations depict the robustness, accuracy, and effectiveness of the designed methods.(c) 2023 ISA. Published by Elsevier Ltd. All rights reserved.

Automated summary

In this paper, a robust distributed consensus control method based on adaptive time-varying gains is proposed for nonlinear multi-agent systems (MAS) with uncertain parameters and external disturbances. The discontinuous and continuous adaptive integral sliding mode control strategies are designed to achieve precise consensus for non-identical MASs influenced by perturbations. An adaptive scheme is used to overcome the unknown upper bound of perturbations. The designed distributed super-twisting sliding mode strategy adjusts the gain of the control inputs and guarantees the proper performance of the protocol without chattering phenomenon. Simulation results demonstrate the robustness, accuracy, and effectiveness of the proposed methods.