Event-Based Fuzzy Stabilization Controller for Uncertain Nonholonomic Systems With Output Constraints: Application to Mobile Robots

摘要

This article introduces a novel event-triggered fuzzy control scheme for chained nonholonomic systems with output constraints and drift uncertain nonlinearities. By utilizing a barrier Lyapunov function (BLF), the constraint requirements for the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$x_{0}$ </tex-math></inline-formula>-subsystem are addressed. On this basis, the state-scaling technique is employed to transform the remaining x-subsystem into an equivalent lower-triangular system, and a systematic event-triggered scheme combining BLF-based backstepping is used to satisfy output constraints and reduce the communication burden. Meanwhile, a fuzzy logic system is applied to approximate the uncertainties. It is demonstrated that the developed stabilization control algorithm ensures the stability of uncertain nonholonomic systems and prevents any violations of output constraints throughout the control process. Besides, the Zeno behavior is successfully avoided. Finally, numerical simulations and experiments conducted on the QBot2e mobile robot are presented to illustrate the effectiveness and applicability of the proposed control algorithm. Note to Practitioners—Nonholonomic systems are prevalent in the engineering field, especially in wheeled mobile robots. The motivation of this article stems from the need to limit the spatial position of an indoor mobile robot, ensuring it operates within a reasonable area while also reducing the communication burden. To meet these requirements, an event-triggered mechanism combined with BLF-based backstepping is developed. This approach not only guarantees specific constraints, but also reduces resource consumption. Furthermore, the scope of the described systems is broadened by employing a fuzzy logic system to approximate the uncertainties of nonholonomic systems. The proposed controller achieves low energy consumption and superior performance, rendering it suitable for practical applications. Two groups of numerical simulations and experimental tests on the QBot2e mobile robot are carried out, verifying the feasibility and applicability of the algorithm. In summary, the event-triggered fuzzy control scheme effectively balances control performance and communication resource usage, addressing the practical control problem of stabilization in uncertain nonholonomic systems.