Process-Threshold-Based Fuzzy Adaptive Prescribed Performance Event-Triggered Tracking Control for a Manipulator System

This paper investigates a process-threshold-based fuzzy adaptive prescribed performance event-triggered tracking control strategy for a manipulator system, which is irrelevant to initial position of the manipulator. A new event-triggering mechanism is proposed based on a newly proposed process threshold method, so that the event-triggering number in the control process is greatly reduced, and the implementing problems of performance constraint control in programmable logic controller (PLC) are solved. Aiming at the situation that the output of the manipulator may be directly perturbed and exceeds the prescribed performance boundary, a new restartable performance constraint function is proposed, and it can also adjust the convergence speed of the performance function more flexibly. Specifically, the design of the function is independent of the initial position of the system. At the same time, the proposed control strategy combines with the design method with a zero initial control input, a fuzzy adaptive prescribed performance event-triggered controller with a startup buffer ability is obtained by adding an input buffer function, which solves both the problem of prescribed performance control for the manipulator with arbitrary initial position and the startup problem with a load. The designed controller can stabilize the manipulator system under lower triggering number, and let the manipulator system track the expected trajectory accurately within a given finite time. The control strategy is easy to apply in real industrial systems.