Research On The Flow-Saturated Resistant Control Technology Of Load-Sensing Hydraulic System

Load-sensing (LS) system, usually employing working model of one pump for multi-actuators, is a type of energy-saving hydraulic system that is widely used in construction machinery. When LS system is in flow-saturated status, the flow delivered to actuators will be affected by load and will not be proportionable to opening of the main valve any more, which can cause serious influence on construction machines operation. So, it is necessary to research the flow distribution during multi-actuators high speed operating.In this paper, based on the project of 30t offshore crane developed by Dalian University of Technology and Shanghai Jinyan Machinery Manufacturing Co., Ltd., the flow control in LS system was further studied. The main work in this paper is summarized as follows.(1) The working principle of multi-actuators LS system was analyzed, and the hydraulic system of 30t offshore crane was designed according to its actual working conditions.(2) The simulation models of LS control valve and pressure compensated valve etc were built based on AMESim, with help of whose models the simulation model of overall LS system of offshore crane was made. In addition, the validity of simulation model was verified through experimental test in 30t offshore crane.(3) The flow-saturated status of LS system was represented with simulation method, and the characteristics of system in this status were identified, all of which was intended to show that the flow delivered to actuators was affected by load in flow-saturated status and would not be proportional to the opening of main valve. In addition to that, the reason of flow delivering disproportion was also analyzed.(4) A new flow-saturated resistant control method for LS system based on pressure decrease sensing control strategy was presented. The results of simulation proved that the new method could make effective use of oil source and keep flow-saturated status off LS system, which could make sure of the cooperativeness of multi-actuator's compound control action.In this paper, simulation model of LS hydraulic system for offshore crane was built up successfully and employed to simulate system under several working conditions, based on which a new flow-saturated resistant control method was presented. All research results were significant in improving multi-actuators LS hydraulic system in construction machinery.