Vehicle Control Strategy Of Pure Electric Tractor And Its V-mode Development

The automobile industry has made great contributions to the development of human society since its establishment,but at the same time it has brought about increasingly serious global problems such as environmental pollution and resource depletion.With the ban on the sale of fuel vehicles in many countries,pure electric vehicles have gradually become the focus of development due to their energy saving and environmental protection,and fast torque response.The technology consisting of electric control,electric motor and battery is the key of pure electric vehicles.The electric control technology refers to the vehicle control strategy responsible for the real-time behavior of the vehicle and its implementation,which is the key to the vehicle’s control function.Based on the actual engineering project,this paper proposes the control system scheme for the functional requirements of the target pure electric semi-trailer tractor.This article adopts the V-mode design method,based on the automotive-grade processor MC9S12XEP100 to develop the designed vehicle control strategy into an embedded vehicle control unit that meets the actual requirement.The main work of the full text is as follows:Firstly,the control system structure and powertrain characteristics of battery electric vehicles,especially tractors and buses,were analyzed.Based on this,the control system scheme and the vehicle controller schematic diagram were designed.Then the vehicle’s dynamic performance was calculated and verified,which providing a theoretical basis for subsequent design and testing.Secondly,vehicle control strategies such as high voltage power-on and power-off,driving mode conversion,and CAN network-based fault handling are formulated to define the actual vehicle behavior.The behavior of the vehicle from start to stop includes: initialization of the vehicle controller,filtering and fault-tolerant processing of the pedal signal,starting the vehicle after power on,constant speed creep control,torque calculation and arbitration during acceleration,and braking and stopping.Thirdly,according to the control strategy and considering the characteristics of actual engineering application,a control system model was built in Simulink environment.After the logic function is verified by the model and software in the loop test,Embedded Coder is used to generate the embedded code,which is integrated with the underlying code in Code Warrior environment to form the complete vehicle controller software.Finally,a processor-in-the-loop test platform was built and tested based on the developed hardware board.Based on the NI Veristand and PXIe-8840 RT processors,a hardware-in-theloop test platform was set up and completed the test.At the end of the article,a real vehicle test was performed on the assembled pure electric tractor.All the test results show that the vehicle control unit designed in this paper responds correctly and quickly,meeting the expected control requirements.