Based On The Load Port Independent Technical Excavator Hydraulic System Control Strategy Research

As the representative of the construction machinery, excavator plays a moreand more important role in society’s construction. With the development of theindustrial needs, people require more and more about the capability of excavator,especially in the aspects of its energy efficiency and controllability. Meanwhile,with the development of the electro-hydraulic proportional technology, theresearch on excavator’s electro-hydraulic proportional technology has becomemore and more in-depth study. This paper focuses on the excavator’selectro-hydraulic proportional technologystrategy based on the load portindependent technology. The load port independent technology is one of theemerging hydraulic technologies, and the key of it applied in the excavator’shydraulic system is the use of load port independent valve in the system.Researches on problems needed to be solved on the load port independenttechnology in our country contain: system’s instability when executingsingleactions, choices of control strategy andpressure impact phenomenon when workcondition changes, flow allocation when multi-actuators control together andpump flow is saturated.Firstly, this paper briefly introduces load port independent technologydevelopment of multi-valve technology in China and other countries, and theapplication of electro-hydraulic proportional technology in excavator.Thestructure and working principle of the load port independent technology isanalyzed and the excavator hydraulic system based on the load port independenttechnology is built.It also establishesmain components’ load port independentvalves’mathematical model of excavator hydraulic system, through which themain spool’s response characteristics to the step signal is researched.Then, the paper shows the calculating principle of flow control strategyandpressure control strategy, and chooses way of combining calculating flowcontrolalgorithm and pressure control algorithm to control the hydraulic systemactuators. Takethe boom cylinder for example. The paper builds its simulationmodel through AMESim software and its controller through matlab/simulink software, so that boom cylinder hydraulic system is simulated throughco-simulation technology.The simulation results are analyzed to prove thecorrectness of control strategythis topic puts forward.Furthermore, based on the executive components’ working needs whenexcavator executes compound actions, the paper proposesthe control strategy ofcompound actions.After analyzingthe simulation results, the control strategywhen doing compound actions is proved to be trueby building the hydraulicsystem’s simulation model when bucket cylinder and boom cylinder worksthrough AMESim software and building its controller through matlab/simulinksoftware, so that boom cylinder hydraulic system is simulated throughco-simulation technology.The paper also designs a software programmerto solvethe flow assignment problems when pump flow saturates and discusses threeflow allocation strategies (priority principle, the same amount reductionprinciple, the same proportional reduction principle) which are proved to be truethrough the co-simulation method.At last, in order to judge the load port independent system’ energy savingcondition, this paper compares the hydraulic pump power consumption of theload port independent system and LUDV system at the same load and velocity.