Distributed control strategy for large-scale hydraulic synchronous lifting systems

Hydraulic synchronous lifting systems consisting of multiple cylinders are of great importance for lifting heavy loads. To achieve high-precision movement of heavy objects, it is necessary to control and synchronize the movements of multiple lifting points. Centralized control station is not suitable for lifting systems in which the cylinders are deployed at large-scale regions. Thus, in this article, we propose a distributed control strategy for the large-scale lifting system where the cylinders cooperate with their neighbors to achieve synchronization. The cylinder nearest to the work station is regarded as a leading cylinder and connected to the work station, while the others are not able to access the command signal from the station. In this article, all of the cylinders are assumed to be equipped with wireless communication modules and their states are accessible to the cylinders within communication range. Each cylinder has its own distributed controller, in which only the neighboring cylinders' information are employed. Through coupling states when designing the distributed controllers, the movements of all the cylinders are driven to be synchronous. Finally, simulations with AMESim are conducted to verify the feasibility and effectiveness of proposed cooperative control strategy.