Bounded Output Feedback Control of Planar Systems With Unknown Nonlinear Structures and Application to Output Consensus

This letter addresses the problem of output feedback stabilization for a class of uncertain planar systems with unknown nonlinear structures. The underlying philosophy behind the proposed approach is primarily to revamp/advance the classical lead compensator with an arctangent function-based mechanism that assures bounded control magnitudes, leading to a new design methodology not only conquering the obstruction in constructing state observers but also directing the design of a bounded output feedback stabilizer. Inheriting and leveraging the stability-increasing capability offered by lead compensators, the resultant controller is capable of dealing with systems even suffering from unknown nonlinear structures and measurements concurrently. The strategy presented is further expanded to formulate a bounded output feedback output consensus protocol for uncertain planar two-agent systems with unknown nonlinear heterogeneous dynamics.