Soc-based Design Method of Power-assist Characteristic Curve of Automobile Electric Power Steering System

Abstract

The invention discloses a method for designing a power assist characteristic curve of an automobile electric power steering system based on SOC. Considering the situation of battery SOC, the SOC is divided into three categories, namely SOC<40% and 40% respectively. <soc<70％及soc>70%; for the case of SOC<40%, the corresponding curve-shaped boost characteristic curve is processed in segments, and for 40% <soc<70％的情况，进行二次指数平滑处理；对soc>In 70% of cases, an exponential smoothing is performed. The present invention reasonably designs the power assist characteristic curve on the basis of considering the battery energy management of the electric power-assisted vehicle, can significantly improve the power steering performance, and avoid the discontinuous power supply of the power assist motor caused by the fast change of the hand torque or the operation of the large hand torque, thereby causing the power steering Difficulties, etc., to ensure that the battery can generate stable power output at various power levels, so that the steering power calculated by the power assist characteristic curve is stable, while ensuring the stability and safety of the power assist, it can maximize the performance of the power assist and save energy.< / soc<70％的情况，进行二次指数平滑处理；对soc>

Description

technical field [0001] The invention belongs to the technical field of automobiles, and relates to an electric power steering system and an energy management system, in particular to a power assist characteristic curve design considering battery SOC. Background technique [0002] The power assist characteristic curve of EPS refers to the relationship between the power assist current of the motor and the steering wheel input torque, vehicle speed, front wheel air pressure, front axle weight and other parameters. Generally, the steering wheel input torque and vehicle speed are considered as the two main parameters. parameters to meet the control requirements. The power assist characteristic curve of EPS is the key technology of EPS software system. The power assist characteristic curve determines the controller (ECU) according to what kind of goal to control the size of the power assist current, to meet the requirements of the power assist torque under different driving condi...

AI Technical Summary

Problems solved by technology

The above design is only based on the curve itself, and does not consider the impact of battery power on vehicle power assistance. When the hand torque changes greatly and the hand torque is large, the battery may not be able to provide the EPS current that meets the requirements, and the EPS system will suddenly power off. , the power steering system will not work instantly, seriously affecting driving safety

[0003] The Chinese patent with the application number 200810202069.7 discloses "Electric Power Steering System with Independently Adjustable Curve Power Steering Characteristics"; its parameter adjustment makes the curve design cycle long, and at the same time, it is impossible to contact the actual situation of the vehicle, so that it can be adjusted according to the vehicle's Adjust the curve according to the actual situation

[0004] The Chinese patent with the application number 201010600546.2 discloses "electric power steering system with double-slope smooth power-assist curve," which cannot guarantee the actual application effect of the power-assist curve in the process of double-slope smoothing with broken lines, that is, whether it can guarantee Continuous supply of battery power, etc.

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