Power Flow Analysis Of Tracked Vehicle Electro-Mechanical Drive System

With the instruction of the concept of all-electric tracked vehicles,the electrification degree of the system is higher and higher.Electro-mechanical transmission system is a kind of electric drive of all-electric powerdrain,which can meet the drivability of the tracked vehicle and satisfy the power demand of the electrical system.So it has become the development direction of tracked vehicle transmission system,and becomes a hot research topic at present.In this paper,the law of power split of the EMT is studied,and the multiobjective power flow optimization control strategy is designed.Based on the steering kinematics,danamics of the tracked vehicle and the unified modeling of the multi-power steering coupling mechanism,the unified formula of the power split of the tracked vehicle in the series EMT system is deduced,and the power flow rule is similar with the relative turning radius.The influence of transmission-mechanism coupling parameters,vehicle structural parameters,road surface conditions and control parameters on the variation of the power split ratio are analyzed.The power distribution law of power-split structure is obtained based on the derivation of the series EMT system,and the power distribution law under the influence of single parameter and multi-parameter is analyzed.The correctness of the theoretical analysis is verified by the low power experimental bench of electro-mechanical transmission.Taking a certain electro-mechanical transmission tracked vehicle for the study,the danamics model is established,the Kalman filter is used to realize the state estimation,and the targets of control strategy are tracked by the LQR state controller.The working characteristics and dynamic power splitting characteristics of each component under different acceleration conditions and different speed control mode are analyzed.The differences between the dynamic and steady-state power splitting are analyzed from the theoretical point of view.Based on the multi-power flow characteristics of the tracked vehicle electro-mechanical transmission system,the drivability,electric power supply performance and fuel economy performance optimization goal are established.The relative membership function is used to gain the relative memberships of the variables to the optimization functions.Using the minimum average weighted deviation algorithm,the corresponding weights of each optimization goal are calculated,so the multi-objective optimization is transformed into the single objective optimization,and the optimal control scheme of the system is obtained.Based on the MATLAB/Simulink platform,the physical model of the electromechanical transmission system is built.The vehicle environment model,the driver model and the fuzzy multi-objective optimization control algorithm based on the minimum average weighted deviation algorithm are constructed.The dynamic simulation of the typical driving conditions is carried out to verify the feasibility of the control strategy.