| With the development of society, the number of excavators has increased quickly. In the course of construct, all the resource consumed, the pollutant released and the noise made by excavators has made a incalculable load to environment and energy, so many excavator manufactures and institutes at home and abroad have taken much research in energy saving. Energy saving includes two sides: increasing energy usage and energy recovery. The former could be realized by technologies such as electro-hydraulic proportional control, EFI diesel engine control, load-sensing control, intelligent matching between pump and engine, etc. And much of these technologies are mature, so it will be hard to improve further. In the background of development of hybrid technology, the last has been used in cars, and improves energy's secondary application, so it attracts a lot of world's largest companies and institute's interest. If the energy regeneration system is used on excavator, it must be helpful for energy saving.To solve the problems such as heating, inactivation, and wearing caused by energy loss when the arm, the boom, and the bucket fall down, based on hybrid technology, this paper proposes an energy regeneration system made up of fluid cylinder, throttle valve, variable displacement motor and engine. In this paper the author builds the model of the system, analysis the relationship between quantitative parameters, variable parameters and system's response frequency, researches on the variable parameters to the impact of efficiency and velocity of energy regeneration system, and work efficiency of the excavator. According to the simulation result and actual situation, a control method to variable parameters is proposed to reach the best result as far as possible.This paper includes several parts as follows:1 This part introduces the mean of energy saving in excavator, the development of control technology in energy saving such as improving the performance of hydraulic components and power matching between energy and pump, the development and application of hybrid system, the application of present energy regeneration system. As the same time, the topic of the paper is raised. The necessity and feasibility of designing a suitable energy regeneration system for hybrid excavator are showed. The content and the research about the topic are overviewed.2 Coordinate systems for arm, boom and bucket in hybrid excavator are founded by using D-H Method. From these coordinate systems a kinematics model is built, and in the end a dynamical model is deduced by Formula Lagrange.3 According to the characteristics of hybrid excavator, a complete potential energy regeneration system is designed. The models of the hydraulic parts are built, and after integrating the models, the transfer function and hydraulic natural frequency of the energy regeneration system are obtained. Several methods for increasing response speed are proposed through analyzing the influence to the frequency by changing variable and fixed parameters.4 According to the dynamic model that built in chapter 2, the load of fluid cylinder is simulated, and through qualitative analysis to the energy that fluid cylinder gets, the smaller part is ignored. In the course of simulation, the influence to the total efficiency of the system by every parameter is analyzed. From this analysis some control methods to the parameters are pulled out to reach the best result as far as possible.5 All the research and results are included, and the direction of the research next is showed. |
PDF Full Text Request