Simulation Research On Dynamic Characteristics Of The Second Hoisting Of Closed Hydraulic System

With more and more widely used of the closed hydraulic system in the construction crane industry, the key technologies of the closed hydraulic system are also becoming increasingly important. Closed hydraulic system used in the hoisting mechanism is the difficulty of its application, and anti-decline control of the second hoisting is one of the key technologies. The dynamic characteristics of system during the second hoisting is an important indicator to measure system performance, which directly affects the life and performance of the entire machine. At present, most of the international well-known manufacturers have mastered the key technology and have widely used in its products, however the domestic research in this area is not deep enough, and the technology is not mature, the result of application is not ideal. So it is necessary to study the dynamic characteristics of the closed hydraulic system of the hoisting mechanism during the secondary hoisting to provide theoretical support and reference for improving the system control mode, optimizing the system parameters and improving the performance of system dynamics characteristics.Based on the AMESim simulation software, this paper analyzes the effect of the main parameters and pipe-rupture valve to the dynamic characteristics of the system, and analyzes the matching of the corresponding parameters. Then a new closed hydraulic system with a constant power which is the source of the brake is designed and analyzed. The research results can provide guidance for the closed hydraulic system design, commissioning and system optimization.(1) The principle of the closed hydraulic system is designed. Then according to the mathematical model the features of the system and the effect of the parameters to the dynamic characteristics are analyzed.(2) According to the principle and calculation results of the parameters, the AMESim model of the system which includes engine, variable displacement pump, relief valve, charge system, hydraulic motor, hoisting mechanism, and break etc, is established. And the theoretical basis of the simplified model and parameters setting are provided to ensure the accuracy of the model.(3) The effect of the parameters to the dynamic characteristics is analyzed. First this paper optimizes the delay coefficient of the system by batch simulation method. Then based on the optimal system, the main parameters and components, including hydraulic piping system, charge system, pipe-rupture valve, are analyzed. Analysis of the different parameters setting when the system with different load, different micro-mobility and during the lowering process.(4) A new closed hydraulic system which with a constant pilot power to control the brake is designed. Then this paper analyzes the difference in the delay coefficient and the time of brake opening between the two systems by the method of simulation..(5) Finally, according to the results of the simulation research, some suggestions are proposed for the design of closed hydraulic system.