Single-Axle Parallel Hybrid Mode Switching For A Heavy Off-Road Wheeled Vehicle

At present,most of the cars are relying on burning oil to obtain power,Energy depletion and environmental pollution is the two major constraints of human development problems,Thus causing a high degree of human attention.With the world's automobile exhaust emissions regulations are increasing.For the car manufacturers,in order to be able to meet emission regulations,so the new energy vehicles occure in such a background.Hybrid both have motor and engine,witch can learn from each other to make up for their own shortcomings,In the performance improvement at the same time can also achieve the purpose of fuel-efficient.The two control problems of hybrid cars are energy management strategy and dynamic coordination control strategy.At present,most of the research is about the energy management strategy.,and made a lot of results,but There are three main types: firstly,it is based on the rules of the logic threshold control strategy;Secondly,it is intelligent control strategy,which based on fuzzy control;The third is based on the optimization algorithm of energy management strategy.Because the hybrid is a multi-power source system,means the car may be driving in different modes in different conditions.In the mode switching process involves the conversion of the power source,due to the significant difference characteristics between the motor and the engine,must be take dynamic coordination control during the mode switching process,ensure that the total output torque is stability,reduce the longitudinal impact of the vehicle caused by the torque fluctuation and improve comfortable.This article relies on a 8X8 heavy off-road wheeled vehicle hybrid system research project,using a single-axis parallel structure,The motor is Installed on between the clutch and the transmission(belonging to the P2 type),mainly research on dynamic coordination control strategy of hybrid system mode switching.Firstly,analyze the structure of the hybrid system.The biggest feature of the system is that the AMT and the clutch are used as pneumatic actuators.Then Calculation the dynamic parameter of the powertrain,determine the parameter value.of engine,motor,clutch,transmission and other components.According to the relevant parts parameters obtained by the manufacturer or test,Using AVL Cruise and Matlab / Simulink for modeling,the model including sub-models of motor,engine,AMT,clutch,battery and vehicle and so on.According to the characteristics of the pneumatic clutch used,proposed fuzzy control of clutch engaging.Based on the existing energy management strategy of the laboratory,the dynamic coordination control strategy with clutch engagement process and the dynamic coordination control strategy without clutch engagement process are developed,and analyzes the evaluation index of mode switching.Then,have a co-simulation of the mode switching process,which is carried out to verify the feasibility of the dynamic coordination control strategy.Finally,according to the experimental requirements,built a single shaft parallel hybrid platform.Based on Freescale 32-bit high-performance 56 xx series of Microcontrollers,finished the underlying program and application program designed,control software programming and compiling;Based on the original TCU data acquisition system,using Microsoft Visual Basic developed a data acquisition debugging and monitoring system of hybrid.Through the CAN bus can achieve 10 ms precision data acquisition and debugging.Finally,download the compiled control program into the Microcontroller,conduct a experiment.Finally,compared and analyzed the experimental results,came to a conclusion that the control strategy effectively reduces the torque fluctuation of the mode state switching process and improve driving comfort and riding comfort.