Control of integrated electro-hydraulic servo-drives in a translational parallel manipulator

This paper deals with the kinematics, dynamics and control of an innovative application of a three degrees of freedom (3-DoF) translational parallel manipulator (TPM) with three independently controlled integrated electro-hydraulic servo-drives (IEHSDs) for the handling of heavy forgings during precision machining. With high payload of the TPM moving platform, IEHSD force and position control was analyzed using adaptive controllers. The main contribution of this study is the IEHSD control architecture, which enables highly accurate synchronization of their position confirmed experimentally during TPM trajectory tracking control. For this purpose, a synchronization controller of three IEHSDs utilizing cross-coupled control (CCC) was proposed. The synchronizing controller ensures precise control of the TPM under conditions of variable heavy technological load.