Research On Forward Modeling And Simulation For Hybrid Loader

Hybrid engineering vehicles have flexible configurations and complex control strategies.It is inevitable that a lot of time and material resources will be spent on testing the effectiveness of the control strategy and the performance of the engineering vehicle through prototype.In the research and design process of hybrid engineering vehicles,appropriate modeling and simulation technology can effectively shorten the development time and reduce R&D costs.Compared with the backward simulation,the transmission path of control signal and energy flow are completely the same as the real vehicle.It has obvious advantages in control strategy development and power performance analysis.This thesis develops a forward simulation model architecture which is suitable for developing control strategies and testing loaders performance.The research content of this thesis mainly includes:(1)Forward simulation model architecture is designed and key components modeling is completed.The forward simulation model of hybrid engineering vehicle on MATLAB/Simulink platform is established,which includes driver model,powertrain model,working cycle model and vehicle dynamics model.(2)Typical working cycle model is constructed.Based on the study of characteristics of the loader V-type working cycle,four characteristic parameters are defined.The characteristic parameters calculated by measured data is divided into 5working sections.The neural network algorithm is used to fit the data of each working segment,and the data variation curve with the smallest comprehensive error of each test operation cycle is obtained.According to the extracted duration characteristics of each working segment,the fitted characteristic parameter data of each working section is spliced to obtain a working cycle model.(3)Based on the research of the control strategy of hybrid engineering vehicles,the vehicle control strategy is modularized according to the function,and the control strategy architecture is constructed.The control strategy is composed of three parts,the operation intention identification module,the vehicle model judgment module and the energy management strategy module.According to the different coupling relationship between power sources,three identification methods for required power are developed.According to the characteristics of the load fluctuation of the engineering vehicle anddifferent coupling mechanics of series system and parallel system,two different energy management strategies are designed.(4)With MATLAB/GUI as the development platform,four operation interfaces including startup interface,parameter input interface,working cycle setting interface and simulation result display interface are designed.Using the forward simulation model,the rationality of the control strategy is verified by simulation results analysis of series hybrid electric loader and parallel hydraulic hybrid loader.The three loaders with different configuration are compared and analyzed in terms of maximum speed,maximum traction,acceleration performance,gradeability and fuel consumption of working cycles.The simulation model of this thesis is able to simulate the performance of the loader and test the control strategy,and provides reference for the research of hybrid loader simulation technology.