Adaptive Event-Triggered Exponential Tracking Control of Parallel Robot Manipulators

This article aims to solve a challenging problem in control of parallel robot manipulators—exponential tracking of the angle and angular velocity for any reference signal. The difficulty is how to separate unknown parameters from error dynamics in the presence of uncertainties and avoid calculation explosions in the construction of an adaptive state-feedback controller. Based on an event-triggered (ET) parameter estimation technique and optimization-based approach, we develop an ET adaptive controller by utilizing the certainty-equivalence principle. Being superior to the existing tracking results, the presented strategy is robust against coupled uncertainties due to the efficient estimation of unknown parameters within a finite time instant. Simulation tests and experiments with hardware-in-the-loop are simultaneously conducted on the tracking control of a five-bar manipulator to demonstrate the effectiveness of the proposed approach.