Distributed synchronous control of multiple electrohydraulic actuators with lumped uncertainty and communication delay

This study presents a distributed synchronous control in multiple electrohydraulic actuators (MEHAs), which ensures the motion consensus between the leader and the follower under a directed topology. Since the MEHAs system has many unknown uncertainties and communication delays, a terminal sliding mode observer (TSMO) is used to address hydraulic parametric uncertainties and load disturbance. Furthermore, one synchronized controller is designed by Lyapunov-Krasovskii method with backstepping iteration to ensure the synchronized errors of the MEHAs system converging to a zero neighborhood. Since some follower EHAs cannot directly acquire the position signal from the leader node, a demand estimation law is used to degrade the negative effect of unknown communication delay existed in the network topology. Finally, the effectiveness of the proposed synchronized controller is verified by a MEHAs platform with finite hydraulic nodes under constant and random communication delays.