Though it is common in network control systems that the sensor and control signals are transmitted via a common communication network, no result is available in investigating the stabilization problem for uncertain nonlinear systems with both input and state quantization. The issue is solved in this paper, by presenting an adaptive backstepping based control algorithm for the systems with sector bounded input and state quantizers. In addition to overcome the difficulty to proceed recursive design of virtual controls with quantized states, the relation between the input signal and error state need be well established to handle the effects due to quantization. It is shown that all closed-loop signals are ensured uniformly bounded and all states will converge to a compact set. Simulation results are provided to validate the effectiveness of the proposed control scheme.

This article investigates the leaderless consensus problem for uncertain high-order nonlinear multiagent systems with event-triggered communication. Under a directed graph condition, a fully distributed adaptive control strategy is presented. The main contributions are summarized as follows: 1) globally Lipschitz condition, as required in many existing literatures, is not needed in this article; 2) for each agent, only one filtered output signal is required to be broadcast to its neighbors, which can effectively relieve network transmission burden; 3) the distributed adaptive controllers and event-triggered conditions are co-designed based on a single Lyapunov function such that continuous monitoring of neighbors’ states is not needed; and 4) by introducing an exponential convergence term to the designed triggering condition, Zeno behavior is avoided while all the agents’ outputs can reach asymptotically leaderless consensus. Moreover, to easily implement the designed triggering condition and further reduce the triggering frequency when the consensus errors converge to the neighborhood of origin, a switching type of triggering condition is presented and bounded consensus can be guaranteed. Simulation results are given to validate the presented distributed consensus control scheme.

In this article, we investigate the output consensus tracking problem for a class of high-order nonlinear systems with unknown parameters, uncertain external disturbances, and intermittent actuator faults. Under the directed topology condition, a novel distributed adaptive controller is proposed. The common time-varying trajectory is allowed to be totally unknown by part of the subsystems. Therefore, the assumption on the linearly parameterized trajectory signal in most literature is no longer needed. To achieve the relaxation, extra distributed parameter estimators are introduced in all subsystems. Besides, to handle the actuator faults occurring at possibly infinite times, a new adaptive compensation technique is adopted. It is shown that with the proposed scheme, all closed-loop signals are globally uniformly bounded and asymptotically output consensus tracking can be achieved.

So far, distributed adaptive consensus problems for uncertain nonlinear multi-agent systems have not yet been extensively studied. Compared with centralised adaptive control, some new challenges need to be well addressed, for examples, (i) how to reach asymptotically consensus tracking with directed topology condition, by using totally distributed adaptive control strategies; (ii) how to ensure globally uniform boundedness of closed-loop systems while achieving leaderless consensus with semi-positive definite Laplacian matrix; (iii) how to maintain system performance while effectively reducing the communication burden among connected agents. This paper is mainly devoted to report some recent advances in distributed adaptive consensus control. Besides, some interesting research topics which are worthy of further investigation will also be discussed.

This article investigates the distributed adaptive attitude synchronization problem for multiple rigid spacecraft with unknown inertial matrices and event-triggered communication. Under a directed topology condition, two distributed event-based adaptive attitude synchronization schemes are proposed. By introducing a reference system for each spacecraft, a distributed adaptive control algorithm is first developed, based on which a group of rigid spacecraft can be synchronized at a common attitude with zero angular velocity. Then, the case without angular velocity measurements is considered. By redesigning the reference system and resorting to a pseudovelocity filter, an event-based adaptive output feedback attitude synchronization algorithm is presented. It is shown that with the proposed control schemes, all the closed-loop signals are uniformly bounded and the attitude synchronization can be achieved, while Zeno behavior in each spacecraft can be excluded. Simulation results are provided to illustrate the effectiveness of the proposed control schemes.