Research On The Closed Hydraulic Regeneration System Of The Boom Potential Energy In Hybrid Excavators

With the continuous development of the world economy, oil consumption become faster and faster. As a non-renewable energy sources, oil will eventually run out. Compared to automobile, engineering machinery have some defects, such as needing more power, energy and low energy efficiency etc. Once more using of hy-brid construction machinery, energy recovery can not only dramatically improve the efficiency of resource use, with minimal consumption of resources to maximize eco-nomic and social benefits, but also can protect the social and economic sustainable development, help build a conservation-oriented society. In the era of increasingly tense in the energy, it can also strength our strategic plan to consolidate and enhance international status. Rational using of energy, improving energy efficiency is an im-portant way to alleviate this problem. Therefore, because of the high energy consump-tion for the machinery, the state putted the issue of hybrid energy recovery to "863" project.The research of this article is based on the "863" project potential energy recovery system of the arm in hybrid hydraulic excavator.Chapter 1 Introduction. The paper indicates the research status and development of the hybrid vehicles in domestic and foreign countries and the major work in the entitle article.Chapter 2 The kinematics and dynamics analysis of Hydraulic excavator boom. The kinematics'analysis of excavator working device is done by DH method and transformation matrix is derived which every coordinate on the basis of the first coordinate to achieve a coordinate transformation between the different coordinates. the speed and acceleration of each device gravity is calculated and we calculate the design formulas of the boom's kinetic and potential energy. The dynamic model is deduced by using Lagrange equation and we obtain the size tolerance on cylinders. This chapter lays a theoretical foundation for Simulation studies. Chapter 3 Mathematical model of the energy recovery system in hydraulic excavator. This chapter describes the composition and working principle of the closed hydraulic energy recovery system. The mathematical models are established, such as hydraulic cylinders, piping, accumulator, pump motors and motor components. Then transfer functions are derived of each part and a mathematical simulation model is derived of the entire hydraulic system. In the end, this chapter analyzes the static and dynamic features of DC motor and designs the double closed loop DC system of speed and current.Chapter 4 Study on the motor speed control algorithm of energy recovery. Dc motor speed loop controller is designed using the fuzzy control and fuzzy-pid control algorithm on the basic of DC mathematical model.Chapter 5 Study on the simulation and experimental of hydraulic excavator en-ergy recovery system. In Matlab/simulink environment, the speed and interference performances of motor are simulated by using fuzzy control and fuzzy-pid control. The instantaneous velocity characteristics are simulated in the variable load and variable flow hydraulic cylinder case. Through simulation of the hydraulic system of energy recovery, the effect of energy is compared under the different circumstance of the accumulator volume and inflation pressure. Simulation obtains using two accumulators and the inflation pressure is 15Mpa that the system can achieve maximum energy recovery which is about 25.4%. The result of energy recovery hydraulic system shows that the efficiency is up to 19.4% when the boom declines and also verifies the correctness of the simulation model.Chapter 6 Conclusion and outlook. This chapter describes the main research work and prospects for future research work.