Research On Energy-Saving Closed Hydraulic System Of Hoisting Mechanism

Hydraulic technology has many advantages,such as convenient control technology,flexible installation,and large power ratio.So it is widely applied in cranes.During the design and the optimization,people pay more attention to the functions and feasibility of the system,but think less about the energy consumption.Especially in lowering case of cranes,the engine still needs to provide energy to prevent the load from falling faster.Usually,the load of crane is large and is moved to a long distance.Therefore,there is more possibility to save energy.The gravitational potential energy recovery and reuse technology for the lifting and lowering cases of the crane hoisting mechanism can dramatically improve the efficiency of its hydraulic system and has great engineering meaning.Consequently,researchers are paying more attention on the energy-saving hydraulic circuit with the accumulator as the energy storage component or the power source component gradually.However,because the oil pressure will change with the entry or release of oil,resulting in interference in the load movement and a greater impact on the crane lifting mechanism with running speed stability command.Therefore,based on the energy utilization characteristics of the hoisting mechanism in the crane and the research progress of the current related technologies,a 5t closed loop hydraulic system of lifting mechanism is studied,and an energy-saving circuit is designed,and the constant rotational speed control strategy of the actuator is proposed according to different working cases.At the end of the paper,the reasonability of the strategy for the hydraulic system is verified by co-simulation technology,and the energy saving and recycling efficiency is calculated.The main work of the paper is as follow:(1)On the basis of learning a few domestic and international research results,the development history of hydraulic technology in practical engineering is summarized,and some accumulator research status and development from various energy in the closed energy-saving hydraulic system are analyzed in the paper.(2)According to the energy-saving hydraulic system diagram,the action method of the system under different load cases are analyzed,the components that have an important influence on the system performance such as accumulator and electromagnetic proportional pressure reducing valve are selected,and the mathematical model of the secondary component circuit driven by the accumulator is derived.(3)Based on the joint action of the main circuit and the energy-saving circuit and the independent action of the energy-saving circuit,the corresponding control strategy is formulated to meet the needs of various loads and actuator speeds in the hoisting mechanism driven by the closed hydraulic system.The strategy realizes constant rotational speed control of the energy-saving loop with the accumulator as the power source.(4)Based on AMESim and Simulink,the physical simulation model and logic control model of the hydraulic system of energy-saving hoisting mechanism are built.The constant rotational speed control strategy reasonability of the hydraulic system of the energy-saving hoisting mechanism is verified by the simulation of the system key parameters under different working conditions.(5)The energy recovery efficiency and energy reuse efficiency including two cases that the main circuit and the energy-saving circuit work together and the energy-saving circuit operates alone are calculated,which are prepared to improve the energy-saving characteristics of the system.