Research On Composite Braking System Of Hydraulic Hybrid Crane

With the development of global economy,the production and inventory of vehicles increases year by year.The car is convenient for people,at the same time,it still has the problems of the brake safety and low energy utilization,so the hybrid vehicle came into being.Using composite braking technology in the hybrid vehicles,not only can recover the braking energy to improve energy efficiency,but also complete the work of complex braking with the traditional brake system,to increase the brake life and to improve the braking reliability.Therefore,composite braking is a key technology of hybrid vehicle research.However,the application of composite braking technology focused on hybrid electric cars,less on the study of hydraulic hybrid engineering vehicles.The truck crane is often in urban roads,which has features such as large quality,frequent starts and stops and low energy utilization.So the introduction of hydraulic hybrid composite braking system to improve its braking reliability and energy efficiency has important significance.Through reading references,present situation is understood preliminarily about the hybrid composite braking technology development at home and abroad.The existing energy recovery braking subsystem in composite braking system is auxiliary braking,recovery of braking energy is limited,and the braking torque distribution is not uniform.In this paper,based on university-enterprise cooperation project "crane hydraulic hybrid system development",using theoretical analysis,simulation and experimental test for further study of hydraulic hybrid crane composite braking system.The research steps of this paper are as follows:With hydraulic hybrid crane as the research platform,based on the structure and working principle of the composite braking system,using mathematical model analyzes the subsystem of gas and liquid in the composite braking system,this paper expounds the control models of secondary components and electric proportional valve;Through the stress analysis of crane braking process,the dynamic model is established.Based on the above mathematical model,the mathematical formula of braking torque transmission is deduced.The department lays the theoretical foundation for control strategy and simulation modeling.To don't change the driver's operating habits and maximize braking energy recovery,constant proportional allocation strategy of braking torque for the front and rear wheel and the optimal distribution strategy of energy recovery for the rear wheel gas and liquid are established;Based on control requirements and influences,the composite braking system is divided into three work modes: emergency braking mode,retarder braking mode and driving braking mode,and the control process of each mode is formulated respectively.Using the AMESim simulation platform,simulation and modeling are formulated for the gas and liquid subsystem of composite braking system,the control strategy and the crane in the process of braking.After the integration,simulation model of hydraulic hybrid crane in the braking process is obtained,the simulation analysis is carried out under the three kinds of brake mode.The correctness of theoretical analysis and the rationality of the control strategy are verified.Transforming hydraulic hybrid crane as experimental prototype,composite braking system experimental scheme is designed.Through to the actual test of experimental prototype,composite braking technique is applied to the hydraulic hybrid crane,which can improve the braking reliability and energy efficiency.The research contents of this paper provide relevant practical basis for the application of composite braking technology in hydraulic hybrid engineering vehicle,which has certain theoretical value and practical significance for the research and development of hydraulic hybrid engineering vehicle products.