Research On Energy Recovery System Design And Control Strategy Of Oil-hydraulic Hybrid Excavator

The traditional energy-saving technology research of excavator has been relatively mature at present,while the emerging oil-electric hybrid excavator has not caused enough recognition in market due to technical development difficulty and cost.Combining with the national science and technology support plan " research and application on hydraulic hybrid energy saving technology based on excavators energy recovery(project number:2015BAF07B06)",this paper set a 21 ton hydraulic excavator as research object,based on the energy recovery technology,proposed a oil-hydraulic hybrid system in which gravitational potential energy of boom falling and kinetic energy of swing braking are recycled through accumulator,then completed the components selection and the development of the prototype.Build the simulation model in AMESim and Simulink by establishing the mathematical model of key elements of oil-hydraulic hybrid system.Put forward four control strategies,compare the oil-saving effect of each one by simulation,and finally verify the handling characteristics and oil-saving effect of the system through real vehicle test.The results show that the oil-saving rate of oil-hydraulic hybrid excavator with energy recovery could arrived at 14.7%,and has no bad effect on the handling characteristics,application prospect is good.The research of this paper provides reference for the design of hybrid excavator with energy recovery system.The research content of this paper is divided into several parts as follows.In chapter 1,introduce the background and significance of this article.Describe the principle,classification and research status traditional energy saving technology and hybrid energy saving technology of hydraulic excavator.Put forward the deficiency of the existing research and the main research content of this article.In chapter 2,according to the ordinary excavator's working principle and working condition,analyze the sources of energy recovery and effective volume that can be recycled.Design a oil-hydraulic hybrid system which set accumulator and auxiliary motor as main components.Then the working principle of the system is analyzed and the hybrid system's influence on the excavator handling characteristics is introduced.In chapter 3,make the oil-hydraulic hybrid system key components selection and parameter matching.According to the working principle of each component,establish the mathematical model of the oil-hydraulic hybrid system based on which the simulation model in AMESim and Simulink was established.In chapter 4,introduce the principle of oil saving control strategy of hybrid control system.Design control strategy of fixed displacement release and variable displacement release and compare the effect by simulation.In chapter 5,build hybrid excavator prototype and introduce the installation of the main components.Complete the control program of oil hybrid system based on Codesys and EPEC 2023 controller and design of data acquisition program based on Lab VIEW.The handling characteristics test and oil-saving effect test has been done on the prototype.The results show that the handling characteristics of oil-hydraulic hybrid system which designed in this article meets the requirements of use,and oil-saving effect is good.In chapter 6,the main research contents and achievements of this thesis are summarized,and put forward some suggestions on the future further research.