Observer-Based Fuzzy Adaptive Formation Control for Saturated MIMO Nonlinear Multiagent Systems Under Switched Topologies

This article addresses the fuzzy adaptive output feedback formation control problem for multiple input and multiple output nonlinear multiagent systems with output saturations and switched topologies. Fuzzy logic systems are employed to model unknown agents, and a state observer is designed to obtain the state information of system. A smooth model is designed to approximate the nonsmooth saturated function by using the continuity of hyperbolic tangent function such that the system outputs can be used for backstepping design. To deal with the nondifferentiable problem of virtual controllers caused by switched topologies, a novel high-order distributed filter is proposed to estimate the local reference signals; then, the continuous local tracking errors instead of the noncontinuous local formation errors are utilized to design the virtual controllers. By utilizing backstepping recursive design, an output feedback formation control scheme is developed. It is proved that the closed-loop signals are all bounded, the leader-follower formation is achieved, and the system outputs are constrained in their saturated bounds. Finally, to show the effectiveness of the developed control method, we apply the developed control method to multiple unmanned surface vehicles).