Moedling and Control Strategy of a Multi-Pump Multi-Actuator Hydraulic System With On/Off Valve Matrix

A single-pump multi-actuator hydraulic system has an amount of coupling loss because the output pressure of the pump adapts the actuator with the highest load and the other actuators with lower loads have to consume the pressure difference in throttling valves. In this paper, a multi-pump multi-actuator system with on/off valve matrix is developed to reduce the coupling throttling loss. The total flow rate of all pumps matches the requirement of all actuators so as to avoid unnecessary increase of installation power. With the help of the on/off valve matrix, on the one hand, the multiple actuators can be decoupled into several single-pump single actuator systems separately in low flow demand. On the other hand, the multiple pumps can interflow to satisfy large flow demand. A two-level control strategy is proposed to achieve energy saving and good precision tracking simultaneously. The first level is to control the on/off switches and actuator modes based on the optimal energy consumption. The second level is to control the pumps and the throttling valves aiming at desired tracking precision. In addition, a compensation strategy is proposed to reduce the flow shock in on/off switches by transiting the control signals smoothly. Finally, the effectiveness of the proposed hydraulic system and control strategy are verified by experimental results