Adaptive Semi-Global Bipartite Average Tracking of Nonlinear Multi-Agent Systems With Input Saturation via Observer-Based Approach

This paper addresses adaptive semi-global bipartite average tracking (SGBAT) for nonlinear multi-agent systems (MASs) with input saturation under two different low-gain feedback based control protocols via observer-based approach. A state observer and an average signal estimator (ASE) are designed for estimating actual states and obtaining auxiliary outputs. By using the estimated states and the auxiliary outputs, a continuous distributed control protocol is first proposed with adaptive gains. By constructing appropriate Lyapunov function, the adaptive SGBAT can be guaranteed for saturated nonlinear MASs by using low-gain feedback technique. Then, for reducing the communication load, an adaptive dynamic event-triggered control (DETC) protocol is developed with two dynamic event-triggered mechanisms (DETMs). Finally, for verifying the effectiveness of the two control protocols, an application simulation example of multiple satellite systems is displayed. Note to Practitioners—The control of nonlinear MASs with input saturation remains a significant challenge in engineering applications, such as formation of multiple satellite systems, synchronization of robot systems, etc. In practical systems, input saturation can lead to performance degradation if not properly addressed. Meanwhile, considering that actual system states are often unmeasured in these scenarios, further complexity arises. To solve the problem, this paper introduces an adaptive observer-based control protocol with a boundary layer function firstly. However, continuous communication between agents can lead to excessive communication overhead in systems with limited resources. To address this, an observer-based DETC protocol is further developed to reduce the communication load without sacrificing control performance. The proposed control schemes, which account for control inputs constrained by maximum and minimum values, are particularly applicable to scenarios like multiple satellite systems, where utilization rate of communication resources and tracking performance under input saturation are critical. The effectiveness of the control protocols is demonstrated through simulation, showcasing its potential for broader application in similar engineering challenges.