SOC-based automobile electric power steering system assisting characteristic curve design method

Abstract

The invention discloses an SOC-based automobile electric power steering system assisting characteristic curve design method. Considering the battery SOC condition, the SOC is divided into three kinds,namely, SOC is smaller than 40%, SOC is larger than 40% and smaller than 70%, and SOC is larger than 70%; for the condition that SOC is smaller than 40%, segment treatment is performed correspondingto a curve assisting characteristic curve; for the condition that SOC is larger than 40% and smaller than 70%, secondary exponential smoothing is performed; for the condition that SOC is larger than 70%, primary exponential smoothing is performed. On the basis of considering electric power automobile battery energy management, the assisting characteristic curve is reasonably designed, the power-assisted steering performance can be remarkably improved, the phenomena that power supply of an assisted motor is not continuous due to the fact that torque of the hand changes rapidly or the hand torque operation is large, and then steering is difficult are avoided, it is ensured that a battery can generate stable electric energy output in various electric quantity stages so that steering assistance calculated by the assisting characteristic curve is stable, the assistance performance is improved to the maximum extent while assisting stability and safety are ensured, and energy is saved.

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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