Independent metering-based leveling system with multi-actuator for energy saving: Modeling, control, and application on large-size forming equipment

A leveling system with multi -actuator, which is crucial for high forming accuracy, becomes a significant energy consumer in the large -size hydraulic press. The challenge lies in reducing pressure losses during leveling while maintaining synchronization accuracy among multiple actuators. To overcome the obstacle, an independent metering valve -based configuration driven by the servo pump control was proposed. The management of these valves' opening and servo motor's speed for energy saving was developed during different forming operations based on energy flow analysis. To ensure the implementation of the management, a control strategy with diagonal error embedded mean value controller during leveling operation, was addressed. To validate the energysaving effects and the effectiveness of the control, a 20 t experimental forming equipment platform with four 4.9 t leveling cylinders, driven by the independent metering configuration, was built. Two working paths with different leveling velocities, i.e., 20 mm/s and 40 mm/s, were implemented. Energy consumption in these two paths was acquired and compared with that in the traditional single -valve configuration. Results showed a reduction in energy consumption by 43.70 % and 30.05 %, with the largest leveling errors being 0.96 mm and 0.76 mm, respectively. Further discussions revealed that the pressure loss can be minimized to 0.91 MPa from 9.32 MPa under working Path I, and to 0.66 MPa from 9.33 MPa under Path II, while the largest errors become 1.10 mm and 0.72 mm with fluctuating partial load, respectively. The results validated the significant pressure reduction for energy saving and the anti -interference ability of the control. The system's promising energy -saving potential, coupled with identical leveling accuracy is of great significance for low -carbon design and operation of large -size forming equipment.