Fault-tolerant formation control of stochastic nonlinear multi-agent systems with time-varying weighted topology

Abstract

In this paper, the fault-tolerant formation control of nonlinear stochastic multi-agent systems in the presence of actuator faults, disturbances, and time-varying weighted topology is considered. While most traditional fault-tolerant control methods in the literature use fixed weights on the topology edges, in this study these weights are considered time-varying using a pre-designed function, which allows formulating the system more realistically. Moreover, in contrast with previous works on fault-tolerant multi-agent systems, in this study, the model of the agents is considered to be stochastic in general. Furthermore, the actuators of the agents are considered to have a time-varying fault of additive and multiplicative types. A passive and an active fault-tolerant controllers are designed based on the back-stepping sliding-mode approach. In the passive method, a constant robust controller is proposed using an upper bound of the faults while, in the active controller, the additive and multiplicative faults are estimated using adaptive laws. The active and passive fault-tolerant controllers guarantee that the formation errors converge to a bounded region near the origin in a mean-square sense and all of the existing signals in the closed-loop system remain bounded in probability. The results of the formation control are extended to consensus control as well. Finally, a stochastic multi-aircraft model and an RLC circuit with stochastic part are used as two case studies to illustrate the effectiveness of the proposed design method.

Distributed attitude consensus tracking control for spacecraft formation flying via adaptive nonsingular fast terminal sliding mode control

“…Remark 4. Equation (16) shows that the proposed controller (15) introduces values estimated by TSMDO ( 6) to (8) to compensate the generalized disturbances if and only if the estimation errors are small, which solves the problem of extra errors generated by the disturbance observer in the initial period. In addition, the proposed control law (15) with the adaptive laws ( 19) and ( 21) has the advantages of simple implementation, fast convergence speed, high accuracy, and no singularity.…”

“…In order to demonstrate the advantage of variable structure (16), the overall control effort metric (OCEM) 3 is used, which is defined as…”

“…4,5 At present, a variety of research studies concerning attitude coordination control methods for SFF can be found in the literature, such as feedback control, [6][7][8] backstepping control, [9][10][11][12] and sliding mode control. [13][14][15][16] Accuracy reduction may happen for SFF concerning actuator failure, limited data transmission rate, and time delay caused by the harsh environment and distance and attitude errors between each spacecraft. Solutions for these problems are given by researchers.…”

“…In addition, when the angular rate sensor fails, the controller may not work with the unavailability of angular velocity. Thus, a distributed adaptive configuration containment control law was designed under directed communication topologies, and estimation of velocity was obtained via a distributed velocity observer in Sun et al 18 Rapid maneuvering capability is always the main concern in designing the control system for the space missions while most of the developed coordinated controllers in the literature are asymptotically stable, [6][7][8][9][10][11][12][13][14][15][16][17][18] which means that the closed-loop system can only converge to the equilibrium point as time goes to infinity. In order to speed up the convergent rate of SFF system, the finite-time control algorithms have been developed, which can guarantee state errors of the closed-loop system to converge to zero in finite time.…”

Fuzzy fault-tolerant containment control for multi-agent systems with unknown nonlinear dynamics

“…In MASs, actuator faults (AFs) typically cause bad performance, or even instability of system (Cetin and Beyhan, 2020; Sakthivel et al, 2018; Siavash et al, 2020; Yin et al, 2020). In recent years, AFs have received considerable attention since they are inevitable in engineering applications.…”