Simulation And Optimization Of Mini Excavator Positive Flow Electrohydraulic Control System

Compared to conventional negative flow system and hydraulic control positive flow system, full-electric positive flow system will be widely used in the excavator system for its operator comfort and good control features. However, the fuel efficiency and other machine performance often can not achieve the desired standard in action, which is still not able to reflect the superiority of the technology. The analysis found that the low degree of co-ordination and control algorithms imperfect solution is the main disadvantage of all-electric control system. Thus, an all-electric positive flow system of a mini excavator has been analyzed.The outline of this thesis is as follows:In Chapter 1, the principle of the excavator has been introduced and several important systems of pump and load power matching have been described. The object of study and research has been raised. That is pump and load power matching based on mini excavators positive flow system of a company.In Chapter 2, the structures and principles of semi-electric pump regulator and all-electric pump regulator have be described. Then the theoretical models of-the two regulators and swing and bucket circuits have been established,In Chapter 3, an AMESim platform has been built to simulate semi-electric and full-electric pump regulator. The characteristics of the pump have been achieved with different parameters of the regulator and the advantages of the all-electric pump regulator have been concluded. Based on the swing circuit and bucket circuit, the problems of all-electric pump regulators have been simulated.In Chapter 4, single pump and dual pump power matching strategy has been proposed for the optimization and improvement of power matching between pump and load in all-electric-pump positive flow control system. For the single-pump circuit, constant power comparator and PID controller have been proposed to achieve the single pump power match. For the double-pump circuit, a full power demand matching principle has been proposed, combined with the single-pump control algorithm. And then an overall improvement in the power control system matches the all-electric pump and load. Finally, the test and analysis on the excavator have been completed to validate the accuracy of the model and control strategy.In Chapter 5, the research work of this thesis is summarized with further prospects.