The Research Of Control Strategy For Parallel Hybrid Hydraulic Excavator

This thesis is based on the parallel hybrid hydraulic excavator power systemmodel, analyzing the working condition, according to the existence of parallel hybridhydraulic excavator model, component parameters, working conditions andenvironmental uncertainties, design the fuzzy control strategy which has strongadaptive ability, strong robustness, used to determine the optimum allocation of theengine and motor torque, achieve the control objective of hybrid hydraulic excavator.In this paper,several studies for parallel hybrid powersystem in hydraulic excavatorcarried out：(1) Researching the existing control strategy of the excavator hybrid system,Pointing out the advantage and disadvantage of them. According to its owncharacteristics of fuzzy control, Proposing the design of fuzzy control strategy,Providing a good basis for the formulation of fuzzy control strategy.(2) On the basis of researching of a certain type excavator’s powertrain andcomponents, using steady-state experimental data to establish the enginemathematical model. Utilizing the motor theory to establish its dynamic model.Established their own mathematical model for supercapacitor and battery on thebasis of their performance characteristics, And using the application ofsupercapacitor and battery composite energy storage device instead of a singlesupercapacitor or battery as energy storage devices.(3) Combinating with the parallel hybrid excavator power system, designing thecorresponding fuzzy logic control strategy of multi-energy as the certain typeexcavator. choosing the difference between the engine demand torque and targettorque ΔT,The value SOC of the energy storage device and the motor speednmas the input parameter, and the engine’s torque coefficient K as the outputparameter, taking the minimum engine fuel consumption and the best powerperformance trade-offs as the design norms for fuzzy control strategy, design a fuzzycontroller.(4) Using MATLAB/Simulink simulation software to simulate the hybridhydraulic excavator power system and ordinary excavators engine power system andto make comparative study, validating the fuzzy control strategy has a better fueleconomy and engine power than ordinary excavator.