Event-Triggered Coordination for Formation Tracking Control in Constrained Space With Limited Communication

Abstract

In this paper, the formation tracking control is studied for a multiagent system (MAS) with communication limitations. The objective is to control a group of agents to track a desired trajectory while maintaining a given formation in nonomniscient constrained space. The role switching triggered by the detection of unexpected spatial constraints facilitates efficiency of event-triggered control in communication bandwidth, energy consumption, and processor usage. A coordination mechanism is proposed based on a novel role ``coordinator'' to indirectly spread environmental information among the whole communication network and form a feedback link from followers to the leader to guarantee the formation keeping. A formation scaling factor is introduced to scale up or scale down the given formation size in the case that the region is impassable for MAS with the original formation size. Controllers for the leader and followers are designed and the adaptation law is developed for the formation scaling factor. The conditions for asymptotic stability of MAS are discussed based on the Lyapunov theory. Simulation results are presented to illustrate the performance of proposed approaches.

Fuzzy Adaptive Finite-Time Cooperative Control With Input Saturation for Nonlinear Multiagent Systems and its Application

“…(i) The system output of agent j, ( ), j yt is set to track the output of the leader or other agent with assigned pose to achieve zero cooperative error in finite time by avoiding collision with other agents and possessing smoothness in the steady-state control input. To achieve this objective, the proposed FAFTCCIS (9) and (12) includes the switching surface with the integration of fraction order (8), the time-varying switching gains (17) and (18), and the on-line compensation of the upper bound (13) of the lumped uncertainties. (ii) Besides the proof of the closed-loop's stability, the application to the intelligent chef [41]- [43] based on the three-link planar robot [44] is presented to verify the effectiveness and robustness of the proposed control.…”

“…Here, (17) and (18), as the operating point is near or away from the switching surface, a higher or smaller switching gain is produced, respectively, so that a saturation of control input can be postponed or avoided. Then, the excess robustness of the closed-loop system is achieved [38]- [40].…”

“…Consider the nonlinear dynamic system (4) in the presence of the lumped uncertainties (10) satisfying the upper bound (11), the FAFTCCIS (14)- (15) with the adaptive law (13) and the time-varying switching gains (17) and (18). Then, the operating point of all agents converges to the switching surface of (8) This article has been accepted for publication in a future issue of this journal, but has not been fully edited.…”

“…Based on neuro-adaptive approximation and a non-smooth feedback, the cooperative robust containment control of the multileader MASs subject to unknown nonlinear dynamics and external disturbances is designed [17]. In [18], the formation tracking control for a multi-agent system in constrained space with the communication limitations is designed. In [19], the leader-following consensus problem of MASs using a distributed event-triggered impulsive control method is designed such that the controller of each agent is updated only when some state-dependent errors exceed a tolerable bound.…”

“…Properties of the above papers are summarized as follows: (i) linear MAS [3], [7], [28]; (ii) second order MAS [9], [13], [22]; (iii) robust (sliding-mode) (finite-time) distributed control [2], [9], [15], [20], [30]; (iv) adaptive (finite-time) distributed control [4], [11], [19], [24], [27], [31]; (v) strict feedback form [26], [29]; (vi) fuzzy (neural) approximation of the unknown nonlinear functions [1], [4]- [7], [13], [15], [27], [29], [32]; (vii) switching formation [18], [25]; (viii) time-varying delays [28]; (ix) iterative learning control [25]; (x) input saturation: [6]; (xi) regulation problem or actuator fault [9], [21]- [23]; (xii) industrial complex process [33]; (xiii) the leader is the desired trajectory for the followers to track [1]- [32].…”