Chattering-free nested adaptive terminal sliding mode control for PEMFC air supply system with event-triggered communication

Aiming at the proton exchange membrane fuel cell air supply system subject to time-varying external load, system uncertainty and limited network communication resources, a chattering-free event-triggered nested adaptive terminal sliding mode controller is first developed to achieve the tracking control of oxygen excess ratio. First, an integral terminal sliding mode function with recursive structure is designed to eliminate the reaching phase of sliding mode control and ensure that the high-frequency switching term only appears in the first derivative of control law. Then, to alleviate the communication burden, an event-triggered control strategy is adopted for the controller-to-actuator channel. Furthermore, a nested dual-layer adaptive law is constructed to adaptively update the robust gain without overestimation, so as to counteract the composite disturbance composed of the lumped system uncertainty and event-triggering error, which does not require priori upper bounds of the composite disturbance and its derivative. Besides, it is theoretically proved that the output tracking error can converge to the origin in finite time and the Zeno behavior can be strictly excluded. Finally, the adaptability and superiority of the proposed event-triggered nested adaptive terminal sliding mode controller are fully validated by a series of numerical simulations and comparative analysis.